Trends Sci. 2025; 22(5): 9513

Bioactive Peptides from Sea Cucumbers and Sea Urchins: Therapeutic Roles and Mechanistic Insights

Tri Rini Nuringtyas^1,2,*, Lisna Hidayati¹, Zuliyati Rohmah¹,

Dewi Kartikawati Paramita⁴, Ahmad Suparmin^5,6, Helmi Hana Prinanda¹,

Qatrun Nada Febryzalita³, Santika Lusia Utami¹, Laili Fitria Zulfa¹,

Budi Khoiri Ardiansyah¹, Siska Noviana Dewi¹ and Yekti Asih Purwestri^1,2

¹Faculty of Biology, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia

²Research Center for Biotechnology, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia

³Postgraduate of Biotechnology, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia

⁴Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia

⁵Department Microbiology, Faculty of Agriculture, Universitas Gadjah Mada,Yogyakarta55281, Indonesia

⁶Biotechnology Study Program, Postgraduate School, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia

(^*Corresponding author’s e-mail: [email protected])

Received: 13 December 2024, Revised: 3 February 2025, Accepted: 10 February 2025, Published: 20 March 2025

Abstract

Marine organisms, especially those in the Echinozoa class like sea urchins and sea cucumbers, have received significant attention for their bioactive peptides that exhibit a wide range of therapeutic potential. This review presents recent research findings related to the extraction, identification, and bioactivity of such peptides. Antioxidant peptides from Echinozoa could protect against oxidative damage by reducing the levels of ROS and increasing the generation of antioxidant enzymes. This might be helpful for developing new therapeutic drugs to cure neuropathic pain. Peptides with anticancer properties isolated from species such as sea urchins have been observed to trigger apoptosis and suppress cancer cell growth through the PI3K/AKT signaling pathway. Peptides that combat fatigue boost endurance by stimulating the NRF2 and AMPK pathways, enhancing energy metabolism and lowering fatigue indicators in animal studies. Antidiabetic peptides from sea cucumber regulate blood glucose through their influence on the IRS/Akt and AMPK pathways, enhancement of insulin responsiveness, and acceleration of wound healing in diabetic models. ACE-inhibitory peptides from sea cucumbers and sea urchins have also exhibited an antihypertensive activity by inhibiting the conversion of angiotensin I to angiotensin II. Due to their membranolytic mode of action, sea urchin-derived antimicrobial peptides-strongylocins and centrocins-express a wide range of activities against Gram-positive and Gram-negative bacteria. Other sea cucumber peptides that improve memory can become an experimental therapy for the improvement of cognitive ability. Although these discoveries sound promising, the main barriers toward clinical use are problems of peptide stability, their bioavailability, and lack of efficient delivery. Addressing these difficulties is critical for increasing the therapeutic effectiveness of Echinozoa-derived peptides in both nutraceutical and pharmaceutical applications.

Keywords: Bioactive peptides, Echinozoa, Sea urchins, Sea cucumbers, Antioxidant, Anticancer, Antidiabetic, Antimicrobial, ACE inhibitory, Memory-enhancing

Introduction

Marine ecosystems are unique resources for pharmaceuticals since marine organisms possess bioactive qualities with substantial promise in biomedical and pharmaceutical disciplines [1]. The extreme conditions of marine ecosystems, including high pressure, salinity, and temperature variations, have compelled marine organisms to develop specialized metabolic pathways. This results in the production of diverse chemical structures with potent biological activities [2]. Among these bioactive compounds, marine-derived peptides have attracted considerable attention because of their distinctive structural properties and potential applications in health-promoting activities [3,4].

Bioactive peptides, typically comprise fewer than 20 amino acids or with molecular weights below 10 kDa [5,6]. These compounds confer a range of health benefits, including reduction of blood pressure [4], cholesterol levels [7], and inflammation [8], as well as inhibition of cancer progression [9], modulation of the immune system [10], and exhibition of antibacterial properties [11]. Antioxidant properties include free radical scavenger and metal ion chelation activity, which also confer additional health benefits [12]. The main advantages of peptides are that they are naturally occurring, biocompatible with the human body, and thus are generally toxicologically safe, mostly with fewer side effects than other drugs [13]. In addition, bioactive peptides act selectively in target tissues to minimize toxicity, besides being effective at low dosages or low concentration. On the other hand, most of the synthetic chemical compounds used in pharmaceuticals have a tendency to accumulate in the body, which may give rise to various problems and adverse effects [14,15].

In addition to their health-promoting characteristics, these peptides’ distinct structural features, structural diversity, and broad range of biological activities make them ideal for pharmacological, nutraceutical, and cosmeceutical applications [16-18]. These peptides are used in pharmaceutical formulations as well as health-promoting dietary mixtures. In cosmetics, polypeptides provide antioxidant, anti-inflammatory, anti-wrinkle, skin-lightening, and wound-healing benefits [19,20]. In the food sector, peptides function as sweeteners, colorants, thickeners, anti-caking agents, emulsifiers, flavor enhancers, and acidity regulators [21]. The distinctive biological properties of marine-derived peptides have generated significant interest in product development within the pharmaceutical, cosmetic, and nutraceutical industries [22,23].

Bioactivity of the peptides is influenced by various structural and compositional elements. The structure of a peptide, therefore, is an important determinant for its bioactivity. Molecular dimensions, charge distribution, amino acid sequence, and hydrophobic or hydrophilic nature are some of the factors which have a direct impact on functional and bioactive properties of peptides [10,24]. In general, the overall conformation of the molecule may be affected by processes like epimerization and may thus alter the bioactivity of the peptide itself. Notably, amino acid composition of peptides affects their resistance to digestive enzymes and intestinal peptidases, hence their bioavailability and bioactivity. High concentrations of acidic and hydrophobic amino acids in peptides have demonstrated increased bioavailability and retained antioxidant activity [25]. Furthermore, the position of certain amino acids in a peptide sequence is important for binding with receptors and inducing functional responses [26]. How these factors influenced the activity of peptides can be observed in Table 1 which summarized the identified peptide sequences derived from sea cucumbers and sea urchins.

Figure 1 Types of peptides comprises from natural peptides and hydrolysate.

Table 1 Summary of data Echinozoa peptides from various species.

Echinozoa	Species	Peptide sequens	Biological activity	References
Sea Cucumber	Acaudina molpadioides	MEGAQEAQGD	ACE-inhibitor	[52]
	Acaudina molpadioides	FLAP	Antioxidant	[52]
	Actinopyga lecanor	GVSGLH	Antioxidant	[52]
	Cucumaria frondose	GPPGPQWPLDF	Antioxidant	[58]
	Cucumaria frondose	GPGMMGP	Antioxidant	[58]
	Cucumaria frondose	APDMAFPR	Antioxidant	[58]
	Acaudina leucoprocta	QIKNITRSRGDGEYQCKEHRM	Antifatigue	[57]
	Acaudina leucoprocta	EACPERASQGQI	Antifatigue	[57]
	Acaudina leucoprocta	NIDQNMQQGIQ	Antifatigue	[57]
	Acaudina leucoprocta	MTMSFYYVSLGNFMKILGF[95]	Antifatigue	[57]
	Apostichopus japonicus	TYPE	Antioxidant & Anti-aging	[94]
	Apostichopus japonicus	FHLPI	Antioxidant & Anti-aging	[94]
	Apostichopus japonicus	PIWL	Antioxidant & Anti-aging	[94]
	Stichopus japonicus	GPEPTGPTGAPQWLR	Antioxidant	[46]
	Holothuria scabra	FNDLGAW	Antioxidant UV-B Protective	[95]
	Holothuria scabra	KFGEGK	Antioxidant UV-B Protective	[95]
	Holothuria tubulosa	ASHLGHHALDHLLK	Antimicrobial	[142]
Sea Urchin	Echinus esculentus	XNPFKKIAHRXCYPKNE	Antimicrobial	[146]
	Echinus esculentus	RXACTVUAQ	Antimicrobial	[146]
	Strongylocentrotus droebachiensis	SGIHAGQRGCSAL	Antimicrobial	[145]

The bioactive peptides from marine species can be obtained either by direct isolation or enzymatic hydrolysis. Bioactive peptides are naturally present in various marine organisms such as algae, sponges, cnidarians, and mollusks. Due to the aquatic environment, these peptides have acquired some unique characteristics, making them strong bioactive compounds [27]. Peptides become physiologically active when they get digested by proteolytic enzymes such pepsin and trypsin, which occur during digestion or microbial fermentation [28,30]. This method may be used on many different kinds of marine sources with high protein content, including macroalgae and microalgae [29] (Figure 1). The intestinal digesting process not only changes peptide profiles, but it may also improve certain bioactivities as antioxidant activity and bile acid-binding capacity [31], ACE inhibitory and antihypertensive characteristics [32,33], and anti-fatigue benefits [34]. Hydrolysate protein is widely used in the food industry because of its high nutritional content, bioactivity, and beneficial properties, which help to generate health-promoting products with antioxidant, antibacterial, anticancer, and antihypertensive effects [35,36]. Despite the promising therapeutic potential of marine-derived peptides, their transition from laboratory research to commercial markets has been limited. Though some peptides and their derivatives have entered pharmaceutical and nutraceutical fields, most of them are still in various stages of clinical and preclinical trials. However, given their remarkable bioactivities, more drugs derived from marine peptides are foreseen to enter the market in the coming years to address various health challenges [20].

Echinozoa, notably sea cucumbers and sea urchins, are excellent sources of bioactive peptides due to their high protein content and ability to survive in many different kinds of marine habitats. Despite ongoing study in this area, researchers still have a limited understanding of the bioactive peptides formed from these species, as well as their modes of action and prospective uses. Bridging this knowledge gap might open up opportunities for using these marine resources in therapeutic and industrial applications.

The main objective of this review is to investigate the potential of sea urchins and sea cucumbers as sustainable sources of bioactive peptides. This study covers the current state of knowledge on bioactive peptides produced from these species, as well as their structural and functional attributes in relation to health benefits. It also discusses various alternative manufacturing processes, including natural extraction and enzymatic hydrolysis, and brings into focus industrial uses and also the hurdles in commercialization. Such critical issues, when covered by this review, would help close the information gap and create a platform for further research and development of Echinozoa-derived bioactive peptides for medicinal and commercial applications.

Peptides of echinozoa

Sea cucumbers and sea urchins, both members of Echinozoa, are rich sources of bioactive molecules because of their unique nutritional profiles and diverse biochemical compounds. These marine invertebrates contain a variety of bioactive substances, including peptides, triterpene glycosides, polysaccharides, phenols, and lipids [37]. Their high content of proteins combined with a low content of fat makes these organisms ideal substrates for the production of bioactive peptides besides providing valued nutritional and health benefits. Indeed, peptides produced by these organisms have been reported showing a wide panorama of biological activities including antioxidant, anti-diabetic, ACE inhibitory, immunomodulatory anti-cancer properties, and neuroprotective among others [38,39] (Figure 2).

Sea cucumber and sea urchin bioactive peptides have been identified and isolated from gonads, body wall, internal organs, and aquaparyngeal bulb of echinoderms [40]. The body wall dermis is composed of collagenous connective tissue, hence it provides a rich supply of physiologically active peptides in sea cucumbers [41]. Sea urchins are known to contain high PUFA content and, thus, have been reported to possess comparable potential to sea cucumbers [42]. Both echinoderms, sea cucumbers and sea urchins, are a rich source of various bioactive peptides with cumulative therapeutic potential. In fact, bioactive peptides demonstrate diverse biological activities owing to their contribution to the health benefits of marine invertebrates. Cumulative reports have shown that sea cucumbers and sea urchins have strong antioxidant [43], antidiabetic [44], anticancer [45], immunomodulatory [46], angiotensin-converting enzyme (ACE) inhibitor [47], anti-fatigue [48], anti-aging [49], neuroprotective [12], antithrombotic [50], wound healing [51] and micromineral chelating [52] properties.

Figure 2 The benefit of Echinonozoa peptides for human health.

Both naturally obtained from Echinozoa isolation and peptides derived from hydrolysis will be interacting in the body through their target proteins to provide the activity [30]. That peptides modulate several physiological responses in the body is brought about by the binding with particular receptors. Interactions here play crucial roles in cell signaling, immune function, and neurological processes. Thus, the peptides targeting the receptors for pro-angiogenic growth factors like FGF, PDGF, and VEGF may favorably influence the process of angiogenesis implicated in several pathologies. Other peptides, on the other hand, can also bind to their receptors in some unexpected ways with novel physiological results [53]. For example, the identification of peptides that could selectively interact with specific receptors, such as EphA4-binding receptors in the nervous system, may open new directions for targeted therapy and diagnostic applications.

More detailed information concerning the specific bioactivities of peptides derived from sea cucumbers and sea urchins, including their action mechanisms and pharmaceutical/nutraceutical applications, will be further elaborated in the following sections in an attempt to profoundly understand their biological potential.

Isolation of peptides from echinozoa

Representative species in the subgroup Echinozoa, such as sea cucumbers and sea urchins, can be optimally developed for extraction and hydrolysis techniques to isolate bioactive peptides with considerable health benefits and functional properties. Generally, the steps involved are pretreatment, enzymatic hydrolysis, purification, and drying. According to Mildenberger et al. [54], each of these steps requires optimization for maximum yield, preserving bioactivity, and ensuring safety.

Preparation entails washing, removal of internal organs, and dry wringing of the bodies of the specimens as an initial process in extracting sea cucumbers. This eliminated impurities, making the raw material suitable for extraction. The dried sea cucumber tissue was ground into a fine powder (200 - 300 mesh) to increase its surface area and improve enzyme accessibility during hydrolysis. During the enzymatic hydrolysis phase, proteolytic enzymes, generally at a concentration of 10 - 20 g per 1,000 g of powder, are introduced to degrade proteins into smaller bioactive peptides. This reaction typically occurs for 30 - 60 min before it is stopped to avoid excessive degradation. After hydrolysis, ultrafiltration was employed to isolate the target low-molecular-weight peptides from the larger molecules and contaminants. The purified peptide solution was spray-dried at room temperature, resulting in a stable and concentrated powdered form of the bioactive peptides. A final vacuum drying treatment at 70 - 80 °C was applied to enhance purity and stability [55].

Although no specific protocols of extraction have been comprehensively reviewed for sea urchins, protocols used for sea cucumbers can be adapted. A pH-shift method can be applied for the isolation of proteins in sea urchins, where proteins are solubilized at different pH and then precipitated. This method has successfully extracted proteins from several tissues in sea urchins. After isolation, hydrolysis was done using some food-grade commercial enzymes such as alcalase and flavourzyme. These enzymes hydrolyze proteins into smaller peptides, which are further assayed for functional properties. In the case of sea cucumbers also, further ultra-filtration and drying is done in order to have the bioactive peptides in stable form [56].

The source of proteins, enzymatic treatment, and processing conditions would be the key factors that would affect the bioactivity of peptides from Echinozoa. The different amino acid compositions and sequences, and thus their bioactivities, may be due to different types of marine tissue. The collagen-rich body walls of sea cucumbers and PUFA-rich tissues of sea urchins are the most appropriate substrates to produce bioactive peptides with better functional properties [57]. Selection and optimization of enzymatic treatments are of equal importance. The types of enzymes used, their concentration, and the order of the reactions determine the type of peptides that are produced. Different enzymes produce peptides with certain bioactivities such as antiproliferative, antimicrobial, antihypertensive, antiglycemic, antitumor, and antioxidative activities . The use of appropriate combinations of enzymes, concentrations, and hydrolysis conditions is very important to optimize the production of peptides responsible for particular health benefits [58]. Extraction conditions should be strictly controlled to preserve the integrity and bioactivity of peptides. The main factors affecting the quality of the final product are temperature, pH, and time of reaction. Too much heat and/or prolonged processing can destroy these sensitive bioactive compounds, reducing their therapeutic potential. Some of the purification techniques whose optimization is of utmost importance in the effective separation and recovery of bioactive peptides while retaining functional properties include ultrafiltration and chromatography [59].

Roles of echinozoa peptides and its mechanism

Sea cucumbers and sea urchins are of wide bioactive properties, hence adding to their potential in the therapeutic field of several disease treatments. Sea urchins have shown remarkable anti virus [42], antifungal [60], antiparasitic [61,62], anti inflammatory [63,64], anti lipidemic [42], antidiabetic [65,66], anticardiotoxic [67] and hepatoprotective [42] as well as gastroprotective activities, which, to date, have been attributed to compounds such as naphthoquinones, PUFAs, and pigments like echinochrome A. Similarly, antioxidant [67-69] anticancer [54,69], antidiabetic [67,70,71], antimicrobial [67,70,72], anti obesity [70], anti thrombotic [73,74] and anti-inflammatory [67,75] activities are well documented in sea cucumbers due to their high composition of triterpene glycosides, polysaccharides, saponins, and lipids. However, while these studies demonstrate the pharmacological potential of Echinozoa, most of the available studies have focused on the broader chemical compounds and extracts rather than the isolation and characterization of specific peptides. Most research on their bioactivities has been limited to organic extracts or enzymatic hydrolysates, without any in-depth exploration into peptide sequences or mode of action. Such is a serious gap in literature, while peptides from these marine species would likely be responsible for much of the health benefits seen and remain unexploited. This gap is foreseen to be filled by further research that should focus on the isolation, identification, and functional analysis of bioactive peptides opening new perspectives for therapeutic applications (Table 2).

Table 2 Summary of bioactive compounds and therapeutic activities of sea cucumbers and sea urchins, with emphasis on non-peptide components.

Echinozoa	Biological activity	Extract/compound	Spesies	References
Sea urchin	Antifungal	Whole body dichloromethate extract.	Diadema antillarum	[60]
	Antiparasitic	Extracts obtained with PBS from the spine and test.	Echinometra mathaei	[61]
		Crude extract and fractionated naphtoquinones pigments from spines and test.	Evechinus chloroticus	[62]
	Antiinflammatory	Diterpenoid isolated from the gonads.	Stomopneustes variolaris	[63]
		Lyophilized gonads.	Mesocentrotus nudus	[64]
	Antilipidemic	Echinochrome-A isolated from test and spines.	Paracentrotus lividus	[42]
		Methanolic extracts obtained from the soft tissues (gonad, mouth and intestine) Echinochrome-A isolated from test and spines.	Echinometra mathaei	[61]
	Antidiabetic	Aqueous extracts from viscera and spines.	Scaphechinus mirabilis	[65]
		Echinochrome-A	Scaphechinus mirabilis	[66]
	Anticardiotoxic	Thermostable fractions of coelomic fluid.	Tripneustes depressus	[66]
	Antivirus	Echinochrome-A isolated from test and spines.	Paracentrotus lividus	[42]
	Hepatoprotective	Echinochromes	Paracentrotus lividus	[42]
	Gastroprotective	Organic/ aqueous extracts, enzymatic hydrolysates, and polysaccharides.	Apostichopus japonicas, Actinopyga lecanora,	[67]
Sea cucumber	Antioxidant	Organic extract, and extracts triterpene glycosides.	Holothuria parva, Apostichopus japonicus, Neothyonidium magnum	[68] [69] [67]
	Anticancer	Organic extract fucoidan fucosylated chondroitin sulphate enzymatic hydrolysates	Stichopus japonicus, Isostichopus badionotus, Cusumaria frondose, Holothuria forskali, Parastichopus tremulus.	[69] [67] [54]
	Antiinflammatory	Fucosylated polysaccharide sulfate.	Holothuria mexicana, Isostichopus badionotus, Pearsonothuria graeffei, Holothuria polii.	[75] [67]
	Antithrombotic	Organic extract	Holothuria parva, Stichopus variegatus.	[73] [74]
	Antimicrobial	Peptide , saponin, and fatty acids	Acaudina molpadioides, Holothuria thomasi Stichopus japonicas	[70] [67] [72]
	Antidiabetic	Phospholipid, cerebrosides, fucosylated chondroitin sulfate, and vanadium	Cucumaria frondose, Acaudina molpadioides, Apostichopus japonicas.	[67] [70] [71]
	Antiobesity	Cerebrosides, and phosphatidylcholine.	Acaudina molpadioides.	[70]

Antioxidant and antiaging

Oxidative stress arises due to an imbalance in the generation and neutralization capacity of ROS that leads to cell damage and degeneration. In oxidative stress, the free radicals have a reaction with proteins, lipids, and DNA by causing cellular dysfunctions, which may lead to the induction of apoptotic cell death and a variety of chronic diseases. This could be countered through neutralizing free radicals, chelation of pro-oxidant metal ions, inhibition of lipid peroxidation, and modulation of the activity of oxidative enzymes through the action of antioxidants such as bioactive peptides and protein hydrolysates [76,77].

The mechanisms of action in antioxidant peptides are scavenging of free radicals by the neutralization of the reactive oxygen/nitrogen species by donation of hydrogen atoms or electrons through processes termed hydrogen atom transfer, HAT, and single electron transfer, SET [78]. Besides, peptides may chelate transition metal ions, reduce the metal-catalyzed oxidative damage, and inhibit lipid peroxidation by stabilizing the lipid membranes. The most interesting thing is that some peptides can even activate endogenous antioxidant enzymes like superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), thus increasing the body’s self-defense against oxidative stress [79] (Figure 3).

The structure–activity relationship (SAR) of antioxidant peptides is quite complicated, and many factors need to be considered: molecular weight, amino acid content, sequence, and the positioning of certain residues of peptides. Peptides with molecular weights below 1,400 Da showed stronger activity as antioxidants because they can interact more with free radicals [80]. Aromatic and positively charged amino acids like cysteine, tryptophan, histidine, and tyrosine increase radical scavenging properties through electron donation [81]. Hydrophobic amino acids, especially proline, could show higher interaction of peptides with the lipid-based radicals and thus improve the antioxidant activity [82]. Moreover, the position and sequence of certain amino acids within a peptide also determine the extent of antioxidant activity. For example, the substitution of leucine with isoleucine internally, but not at the N- or C-terminal, enhances antioxidant activity [83]. The electronic, hydrogen-bonding, and steric effects of amino acid residues, especially in tripeptide sequences, also impact antioxidant activity. The peptide chain’s steric structure and chemical interactions at both termini might help or hamper reactive oxygen species neutralization [81].

Figure 3 Antioxidant mechanism of peptides derived from sea urchins and sea cucumbers.

The antioxidant activity of peptides is influenced by their structural characteristics such as amino acid composition, sequence, and size [84]. Certain amino acids, particularly tryptophan, tyrosine, cysteine, and homocysteine, have shown antioxidant abilities at physiological concentrations [85]. The antioxidant capacity of peptides is closely related to their molecular mass, hydrophobic amino acid residues, acidic amino acids, and specific antioxidant amino acids. Interestingly, the interaction of peptides with phenolic compounds can affect their antioxidant capacity profile, potentially increasing the cellular antioxidant activity [86]. This suggests that the presence of specific amino acids may be the key to enhancing antioxidant activity [87]. These structural traits demonstrate the difficulty of creating and discovering antioxidant peptides with optimal functions

Several studies have demonstrated potent antioxidant activity of peptides derived from sea cucumbers. Peptide hydrolysates from Apostichopus japonicus (AjPH) have been shown to significantly reduce ROS levels and enhance antioxidant defense mechanisms in Caenorhabditis elegans, highlighting their potential in combating aging and cancer-related oxidative stress [88]. Peptides of Acaudina leucoprocta have been reported to increase longevity in C. elegans. It enhanced the lifespan of C. elegans by up to 31.46 %, mainly due to increased resistance to oxidative stress, reduced accumulation of age-related pigments, and activation of the DAF-16/DAF-2/SOD-3/OLD-1/PEPT-1 signaling pathway that regulates antioxidant defenses and longevity [89]. In another study, peptides from Holothuria leucospilota, prepared by enzymatic hydrolysis using alcalase and flavourzyme, showed potent antioxidant activities by scavenging superoxide radicals and reducing mitochondrial oxidative damage [90]. These peptides prevent also glutathione depletion and mitophagy of neuroblastoma cells, which further illustrate their neuroprotective actions. Other works have pointed out that peptides from sea cucumber can enhance cell viability after UV-B treatment. This work also has shown that hydrolysates can increase the survival rate of HaCaT cells (keratinocyte cell lines) [91]. Interestingly, peptides digested with trypsin show strong antioxidant activities compared to peptides digested with other enzymes [41]. Bioactive peptides from sea urchins also possess excellent antioxidant activity. Two peptides, SnP7 (AAVPSGASTGIYEALELR) and SnP10 (NPLLEAFGNAK), with molecular weights of approximately 1,173.34 and 1,805.03 Da, respectively, isolated from the purple sea urchin (Strongylocentrotus nudus), reduce ROS levels and upregulate the expression of antioxidant enzymes superoxide dismutase-3 (SOD-3) and heat shock protein-16.2 (HSP-16.2) in oxidation-stressed nematodes [86]. These peptides also induced nuclear translocation of DAF-16 and expression of stress-related genes, further enhancing their antioxidant potential (Table 3).

It was demonstrated in the in silico experiment that tryptophan-rich peptides of sea urchin origin have remarkable antioxidant abilities, simply because of this amino acid’s peculiar chemical nature that assists the peptides in giving a more active neutralization response toward ROS [86]. The hydrolysates of protein from Holothuria leucospilota reduce ROS production and mitochondrial superoxide level, hence supporting mitochondrial health and preventing oxidative stress-related damages [92]. Other than anti-oxidative activities, peptides from Apostichopus japonicus showed anti-aging activity: Gradual decrease of pigmentation was identified along with the potential for life span extension. These effects are likely closely related to their unique physicochemical properties, as was confirmed by the in silico analysis [93].

Table 3 Peptides derived from sea cucumbers and sea urchins exhibit antioxidant activity.

Species	Peptides	Outcomes	Activities	References
Acaudina leucoprocta	CFH	Improve learning memory and cognitive impairment	Antioxidant	[90]
Stichopus variegates	SVH-PF, SVH-CAH-PF	Up-regulate Klotho expression, activating SOD and GSH-Px; inhibit lipid peroxidation and protein oxidation	Antioxidation, antiaging	[85]
Apostichopus japonicus	AjPH(GF2, GF3)	Increase the survival rate; reduce ROS level; delay physiological aging	Antioxidant, antiaging	[88]
Apostichopus japonicus	TP-WW-620, TP-WW-621, TP-WW-623	Protect cells against hydrogen peroxide; reduce the oxidative stress induced through the depletion of cellular glutathione; decrease mitochondrial superoxide levels; alleviate mitophagy in human neuroblastoma cells	Antioxidant	[88]
Sea cucumber	SCP-1, SCP-2	Improve exercise performance in mice; reduce metabolism accumulation and muscle injury and enhanced glycogen storage in mice; inhibit oxidative stress and enhance energy metabolism in mice; modulate oxidative stress and mitochondria function-related protein expression in the skeletal muscles	Antifatigue, oxidative stress, mitochondrial	[106]
Strongylocentrotus nudus	SnP7, SnP10	Reduce reactive oxygen species (ROS) level and the expression of superoxide dismutase-3 (SOD-3) and heat shock protein-16.2 (HSP-16.2) in oxidation-damaged nematodes; induce DAF-16 nuclear translocation and the expression of stress-related genes, such as sod-3	Antioxidant	[86]

Sea cucumbers and sea urchins have demonstrated promising anti-aging properties because of their peptides and other bioactive compounds. These marine invertebrates possess potent antioxidant and anti-inflammatory activities, both of which are crucial for slowing down the aging process and protecting against age-related diseases [90]. Research has explored the relationship between oxidative stress and aging in various sea urchin species of different lifespans. Studies on short-lived Lytechinus variegatus, long-lived Strongylocentrotus franciscanus, and intermediate-lived Strongylocentrotus purpuratus revealed that negligible senescence in longer-lived species is linked to sustained antioxidant capacity and stable proteasome enzyme activity, which together reduce the accumulation of oxidative damage over time [46]. The insulin/IGF-1 signaling (IIS) pathway is a key pathway associated with aging. Inhibiting the IIS signaling pathway can extend lifespan and delay age-related diseases in animal models. The key molecules in the IIS pathway include DAF-2, AGE-1, and DAF-16. Autophagy gene cascade signaling, acting downstream of the IIS, can modulate autophagy, affect aging, and regulate anti-aging activity [94]. Moreover, peptides of Acaudina leucoprocta have been reported increase heat resistance and mobility in nematodes, which further justifies their use in healthy aging. More interestingly, antioxidant peptides prepared from oyster Pinctada fucata have been reported to prevent photoaging of the skin. Such peptides retard wrinkle formation, maintain skin elasticity, and regulate lipid peroxidation by preserving the activities of antioxidant enzymes like SOD, GSH-Px, and CAT [90]. Though not on sea cucumbers and sea urchins, this current research indicates the promising avenue of anti-aging in a marine-derived peptide.

Anticancer properties

Bioactive peptides have received great attention as promising candidates for anticancer therapies due to their excellent specificity, good cellular permeability, robust target engagement, and acceptable safety profile. Their multifaceted modes of action can allow them to target cancer cells with a minimal deleterious effect on healthy organs. Such peptides can kill cancer cells through membrane disruption, inhibition of intracellular signaling pathways, or interference with the cell cycle [76]. Besides, the anticancer peptides (ACPs) can be designed to preferably interact with cancer-specific receptors or proteins by acting as agonists or antagonists. They can also be used for diagnostic imaging agents or even theranostic agents with combined therapeutic and diagnostic functions [95].

Numerous studies have documented the anti-cancer properties of bioactive peptides derived from sea cucumbers. Sea cucumber-derived compounds, including peptides, have been reported to possess anticancer activity [96]. The cytotoxic activity of peptides derived from sea cucumber has been reported for Isostichopus badionotus hydrolysates, and ultrafiltered fractions showed cytotoxic activity against colorectal HT-29 cells, marking the first such report for sea cucumber peptides [97]. Likewise, organic extracts of Stichopus horrens exhibited cytotoxic activities against A549 lung cancer and TE1 esophageal cancer cells with IC₅₀ values of 15.5 and 4.0 μg/mL, respectively [98]. In addition, sphingoid bases from sea cucumber cerebrosides induce apoptosis in DLD-1, WiDr, and Caco-2 colon cancer cells, suggesting that these compounds could be a good bioactive dietary food component to suppress colon cancer [99]. In this direction, other cyclic peptides, geodiamolides A, B, H and I, extracted from the sponge Geodia corticostylifera expressed their anti-proliferative activities against the 2 human breast carcinoma cell lines T47D and MCF7 by inducing disorganization in actin filaments. In another study, MCF-7 tumor cells were treated with sea cucumber peptides. The results showed that sea cucumber peptides could activate the apoptotic pathway via PI3K/AKT signalling [44]. Peptides from H. leucospilota may block several proteins that regulate the cell cycle in multiple cell lines including NIH-3T3, HaCaT, and 16HBE. These peptides may also activate the apoptotic pathway and induce apoptosis in these 3 cell lines. Moreover, such peptides could inhibit the migration of cancerous cells and may have applications in the design of anticancer compounds [100]. Showing more evidences of anticancer activities, ESC-AQ fraction, the aqueous fraction from edible sea cucumber Holothuria edulis, exerted a robust cytotoxic action on human leukemia cells HL-60. In fact, by using flow cytometric analysis, the ESC-AQ was confirmed to induce the apoptotic body formation of HL-60 cells [101]. This is an upregulation mechanism for the pro-apoptotic proteins Bax and caspase-3, while the anti-apoptotic protein Bcl-xL is downregulated. The mechanistic studies have also pointed out that peptides from sea cucumbers could activate the PI3K/AKT signaling pathway, which is in charge of cellular growth, death, and metabolism. This system, once being activated by peptides from sea cucumbers, suppresses PTEN, leading to a change in glucose metabolism and energy generation which promotes the death of tumor cells. This route is blocked by these peptides, reducing the ability of tumor cells to wildly proliferate and survive [39].

Although less studied, peptides derived from sea urchin have also shown potential anticancer activities. In silico analysis of peptides from the species Arbacia lixula indicated that these peptides may inhibit proteins involved in NSCLC, including EGFR, PI3K, BRAF V600E, and JAK3 [102]. This suggests their potential to target multiple signaling pathways critical for the survival and proliferation of cancer cells. Indeed, peptides obtained from S. nudus SnP7: AAVPSGASTGIYEALELR; SnP10: NPLLEAFGNAK have shown in vitro induction of apoptosis and retardation in the development of cancer. Peptides down-regulated ROS levels by up-regulation of stress-responding gene expression such as SOD-3 and HSP-16.2, thereby showing dual potential in alleviation of oxidative stress and induction of death of cancerous cells [86].

Based on the cumulative research conducted to date, bioactive peptides from sea cucumbers and sea urchins have been found to exhibit anticancer properties through several interrelated mechanisms. One of the major pathways involves the induction of apoptosis, where peptides upregulate pro-apoptotic proteins such as Bax and caspase-3, while downregulating anti-apoptotic proteins such as Bcl-xL, leading to programmed cell death in cancer cells [101]. These peptides further disrupt important cancer signaling pathways, including PI3K/AKT and STAT3, critical for cancer cell survival, proliferation, and metabolic pathways. Suppression of such pathways interferes with glucose metabolism and triggers programmed cell death to affect cancer growth [103]. Indeed, some peptides also prevent the migration and invasion capability of cancer cells by disrupting the structures, thereby reducing metastatic occurrences, which is evident in in vitro experiments carried out with peptides obtained from Holothuria leucospilota [104]. Another important process is the modulation of oxidative stress. By decreasing the levels of ROS in cancerous cells, these peptides induce oxidative stress in malignant cells while normal cells are protected, thereby making the environment unfavorable for tumor survival and thus leading to the death of cancerous cells [86]. Collectively, these processes demonstrate the great therapeutic potential of Echinozoa-derived peptides in cancer prevention and treatment (Figure 4).

Figure 4 Anticancer mechanism of peptides derived from sea urchins and sea cucumbers.

Antifatigue

Bioactive peptides derived from sea cucumbers have shown promising anti-fatigue effects, primarily by improving energy metabolism, enhancing antioxidant capacity, and regulating key signaling pathways. In animal studies, sea cucumber peptides have demonstrated the ability to significantly improve exercise performance and alleviate fatigue symptoms. Research indicates that peptides can prolong exhaustion time during swimming tests and increase forelimb grip strength in mice. Hence, 2 peptides with different degrees of hydrolysis from A. leucoprocta were tested in mice, and both peptides significantly enhanced endurance and reduced fatigue [105]. Notably, the peptide with a higher degree of hydrolysis produced stronger antifatigue effects, as evidenced by prolonged exhaustive swimming time, increased forelimb grip strength, reduced metabolite accumulation (such as blood urea nitrogen (BUN) and lactate acid), and elevated muscle glycogen and energy metabolism levels.

These antifatigue effects are closely associated with the activation of the nuclear factor erythroid 2-related factor 2 (NRF2) and AMP-activated protein kinase (AMPK) signaling pathways. AMPK pathway activation potently improves energy production by enhancing peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), a principal regulator of mitochondrial biogenesis. Subsequently, NRF1 and TFAM are activated, further enhancing mitochondrial function and energy metabolism. Thus, this increased mitochondrial activity enhances energy metabolism, reducing fatigue. Further, sea cucumber peptides may stimulate mRNA and protein expressions involved in genes of lipid catabolism, mitochondrial biogenesis, and gluconeogenesis, further contributing to enhanced energy use during exercise. With the heightened quantity and activity, there is higher efficiency in the production of ATP, enhanced oxidative phosphorylation, both events summing up to alleviate fatigue. Moreover, the NRF2-Keap1 pathway plays an important role in decreasing oxidative stress through the activation of antioxidant defenses and further supports antifatigue properties of peptides described above [106].

Recent research has also put forward the role of bioactive peptides in modulating metabolic factors related to physical endurance [107]. For instance, peptides from sea cucumbers have been reported to modulate enzymes involved in glycogen storage and fatty acid oxidation, thus supplying energy during prolonged exercises. Such peptides improve physical performance and delay the onset of fatigue by enhancing mitochondrial function and reducing oxidative damage. Considering antioxidant properties and metabolic regulation, the fact that studies related to peptides from sea urchins are few is highly promising. Further research will be required in order to fully investigate the antifatigue properties of peptides from sea cucumbers and sea urchins and their applications relating to sports nutrition and functional food products.

Antidiabetic

Bioactive peptides have emerged as highly promising antidiabetic agents, as they demonstrate the capacity to modulate key enzymes and pathways involved in glucose metabolism and insulin signaling. The antidiabetic properties of these peptides are manifested through multiple mechanisms, including the inhibition of carbohydrate-digesting enzymes, modulation of the insulin pathway, and regulation of oxidative stress and inflammatory processes (Figure 5).

Figure 5 Antidiabetic mechanism of peptides derived from sea urchins and sea cucumbers.

These peptides act to regulate the level of blood sugar by inhibiting the action of enzymes α-amylase and α-glucosidase, which breaks down carbohydrate foods into glucose. Inhibition of these enzymes reduces the gut absorption rate, hence preventing sharp blood glucose elevation, the same as pharmacological anti-diabetic agents, acarbose [108]. Apart from that, these peptides may influence GLP-1 activity by inhibiting DPP-IV and, therefore, play an important role in enhancing insulin secretion and promoting blood glucose homeostasis [108,109]. Some bioactive peptides have been reported to exhibit improved insulin sensitivity and the promotion of insulin production, just like conventional drugs prescribed for this purpose, such as metformin [110].

Sea cucumbers contain a variety of bioactive substances, including peptides, polysaccharides, and lipids, all of which contribute to their strong anti-diabetic capabilities [50,53]. For example, gonadal protein hydrolysates from Cucumaria frondosa have been demonstrated to reduce blood glucose and glycated hemoglobin (HbA1c) levels in diabetic rats. Treated mice also consumed less water, a common sign of diabetes, indicating successful glucose management. Histological analysis revealed that these peptides protected liver tissue, most likely by modulating glucose metabolism via the activation of the IRS/Akt signaling pathway and the AMP-activated protein kinase (AMPK) pathway, both of which regulate lipid metabolism [105]. Further, peptides derived from sea cucumbers demonstrated positive effects in wound healing on a diabetic model by reducing the pro-inflammatory cytokines like IL-6, IL-8, and TNF-α, reactive oxygen species, while increasing the albumin, prealbumin, nitric oxide, and vascular endothelial growth factor, thus aiding the tissue and vascular repair mechanisms [110]. These findings shed light that peptides of sea cucumber play a dual role not only in the control of blood glucose but also in wound healing, an important part of treating diabetes.

On the molecular level, bioactive peptides from Echinozoa may increase insulin receptor sensitivity, thus enhancing the efficiency of insulin signaling. The IR undergoes autophosphorylation upon binding of insulin, leading to the activation of IRS. This will initiate a variety of downstream pathways such as PI3K/Akt and MAPK pathways that are necessary for glucose uptake and metabolic regulation [111]. The activated PI3K pathway initiates a phosphorylation cascade via PDK1, which activates the Akt/PKB proteins. Akt enhances the translocation of glucose transporters GLUT4 to the cell membrane, thereby increasing the rate of glucose uptake in both muscle and fat cells. Meanwhile, activation of the MAPK pathway occurs via the GRB2/SOS/Ras/MAPK cascade, phosphorylating ERK1/2; these events support the promotion of cell proliferation and differentiation to further support metabolic health. The AMPK pathway further interacts with NRF2 to regulate energy metabolism and oxidative stress. Phosphorylated AMPK enhances the expression of PGC-1α, facilitating mitochondrial biogenesis and enhancing the oxidation of lipids. This enhances energy balance and glucose utilization. Activation of the NRF2-Keap1 complex further diminishes oxidative stress, which is one of the major factors contributing to insulin resistance [107]. Peptides from Echinozoa have also demonstrated enzyme inhibition, regulation of insulin pathways, and reduction in oxidative stress-all of which enhance their potential as a natural antidiabetic drug. The ability to target multiple pathways gives some advantage over single-target conventional medications; hence, they are an exciting candidate for incorporation into functional foods and nutraceutical products in the prevention and control of diabetes [109,112]. However, further study is required to completely understand their mechanisms of action, enhance bioavailability, and assess effectiveness and safety in clinical settings.

ACE-inhibitor

Bioactive peptides from sea cucumbers and sea urchins have shown considerable potential as natural ACE inhibitors with possible applications in hypertension treatment. ACE regulates blood pressure by converting angiotensin I to angiotensin II, which is a potent vasoconstrictor, and also degrading bradykinin, which is a vasodilator [113,114]. ACE inhibition prevents the synthesis of angiotensin II while bradykinin levels are maintained, causing vasodilation, a reduction in blood volume and, finally, a reduction in blood pressure [115]. This inhibition is often competitive, such as for some dipeptides generated from milk proteins, but the inhibitory mechanisms of marine-derived peptides include non-competitive and mixed inhibition [116].

Numerous investigations have revealed strong ACE-inhibitory peptides derived from sea cucumbers. The peptide NAPHMR, obtained from the gonad hydrolysate of Stichopus japonicus, had the most significant ACE-inhibitory action, with an IC₅₀ of 260.22 ± 3.71 μM [117]. Three non-competitive inhibitory peptides—DDQIHIF, HDWWKER, and THDWWKER - extracted from the gonads of Apostichopus japonicus shown ACE-inhibitory activity with IC₅₀ values of 333.5, 583.6 and 1291.8 μmol/L, respectively [118]. The ACE-inhibitory action of these peptides is affected by the type of sea cucumber and the particular circumstances of enzymatic hydrolysis employed. Hydrolysates from Holothuria atra generated with alcalase exhibited the highest ACE inhibition, with an IC₅₀ value of 0.32 mg/mL [119]. Collagen hydrolysates from sea cucumbers have been shown to reduce ACE activity and improve vascular function, contributing to their antihypertensive properties [120]. Bioactive peptides from Stichopus vastus also exhibited significant ACE-inhibitory activity and could be potentially used in functional foods and nutraceuticals for the management of hypertension [121].

Studies on revealing the mechanism of ACE-inhibitory peptides from sea cucumbers exhibits that the peptides bind to the active site of the ACE enzyme, block the conversion of angiotensin I to angiotensin II and inhibit bradykinin breakdown. The binding contact comprises hydrogen bonds, hydrophobic interactions, and coordination with the enzyme’s Zn⁺-binding motif, which is important for ACE function. In silico molecular docking studies indicate that the NAPHMR peptide blocks substrate access by interacting with ACE’s S2 pocket and Zn²⁺-binding site via hydrogen and π-bond interactions [117]. Similarly, the peptides DDQIHIF, HDWWKER, and THDWWKER from A. japonicus were discovered to stabilize within the ACE protein cavity, boosting their inhibitory impact via strong contacts with the enzyme’s active region [118]. Interestingly, these peptides show non-competitive inhibition, attaching to places other than the active site, changing the enzyme’s structure and decreasing its activity. In contrast, peptides from Holothuria atra hydrolysates demonstrated a mixed inhibitory pattern, indicating that marine-derived peptides can affect ACE activity via a variety of ways [119].

Aside from direct ACE inhibition, certain peptides may alter larger signaling cascades important to vascular health. ACE inhibitors have been demonstrated to stimulate casein kinase 2 (CK2), which phosphorylates the ACE serine residue, activating the MKK7/JNK pathway. This, in turn, phosphorylates c-Jun, boosting the activity of activator protein 1 (AP-1) and encouraging the production of cyclooxygenase-2 (COX-2), a critical enzyme in regulating vascular inflammation [106]. Additionally, ACE inhibitors can cause MYH9 phosphorylation, which stabilizes ACE in the plasma membrane and influences blood vessel tension [122].

The ACE-inhibitory peptides found in sea cucumbers and sea urchins not only contribute to maintaining blood pressure but also provide other cardiovascular advantages by controlling oxidative stress, inflammation, and vascular remodeling. Their multifaceted approach, along with their natural nature, makes them promising candidates for the creation of antihypertensive functional foods and nutraceutical products. Furthermore, peptides such as Muracein A from Nocardia orientalis are highly selective for ACE while having little impact on other zinc-dependent enzymes, indicating the possibility for designing focused medicines with low side effects [123]. Further structure-activity relationship studies, improvement in bioavailability, and determination of their long-term safety and efficacy in clinical trials would be required. Investigating additive effects with existing anti-hypertensive drugs may provide novel opportunities for combination therapy.

Antimicrobial

In this regard, bioactive peptides obtained from sea cucumbers and sea urchins showed very important antibacterial activity and hence are interesting candidates for the development of new therapies against microbial diseases. Antimicrobial peptides (AMPs) represent key components of innate immunity in marine invertebrates and usually show broad-spectrum activity against Gram-positive and Gram-negative bacteria and fungus [124]. Being of natural origin, their multi-targeting modes make them very effective options for conventional antibiotics in view of the development of resistance.

Several novel AMPs have been discovered in sea urchins. Notably, strongylocins 1 and 2 isolated from the green sea urchin (Strongylocentrotus droebachiensis) have substantial antibacterial action against a variety of bacterial infections [125]. These defensin-like peptides are cationic and disrupt bacteria membranes. In another study, peptide fractions with high antibacterial activity were isolated from the brown sea urchin S. nudus [126]. Further investigation of the red sea urchin Pseudocentrotus depressus led to the identification of amino acids like arginine, glutamine, phenylalanine, and threonine that assist in the antimicrobial defense of the organism [127]. Centrocins 1 and 2 are isolated from S. droebachiensis and Echinus esculentus, respectively, 2 other potent antimicrobial peptides found in sea urchin. Centrocins contain a heavy and light chain, and their antibacterial activities appear to reside primarily in the heavy chains. Their antibacterial activity is connected to the C-terminal amino acids (Gly and Arg), which play an important role in breaking bacterial membranes [128,129]. Centrocin 1, which is stored in phagocyte vesicles, is activated to generate phagolysosomes upon bacterial infection, showing its critical involvement in the sea urchin immune system even during the larval pluteus stage [130].

Sea cucumbers have been demonstrated as well to have high levels of AMPs. The methanolic extract of Holothuria parva’s intestinal tract demonstrated significant antifungal and antibacterial activity, with minimum inhibitory concentrations (MICs) of 0.09 mg/mL against Saccharomyces cerevisiae and 0.04 mg/mL against Staphylococcus epidermidis [130]. This extract showed less efficacy against more resistant bacterial strains, including Candida albicans, Pseudomonas aeruginosa, and Klebsiella pneumoniae, thus displaying selective activity against microbes. Lysozymes from sea cucumbers have been reported with high antibacterial activities against Gram-positive and Gram-negative bacteria. Notably, the C-terminal peptide (SjLys-C) from the species Stichopus japonicus was identified and appeared to enhance the activity after heating treatment [131]. Antimicrobial peptides - The coelomic fluid of Cucumaria frondosa possesses antimicrobial peptides. This peptide showed an approximate molecular weight of 6,000 Da and proved to be efficient at pH 5. [132]. Furthermore, peptides derived from sea cucumber hemolytic lectins have been transformed into new AMPs, CGS19 and CGS20, which exhibit significant anti-MRSA efficacy via 2 mechanisms: compromising membrane integrity and blocking the folate biosynthesis pathway [119]. Furthermore, peptides derived from Holothuria tubulosa have shown inhibitory efficacy against Listeria monocytogenes, a common foodborne pathogen. These peptides exert inhibitory action on bacterial growth and limit biofilm formation, a key event in persistent infections and antibiotic resistance [133]. The molecular dynamics simulations highlighted that the tertiary structure and its amphipathic characteristics confer on these peptides the capability of interacting effectively with bacterial membranes, thus compromising their integrity.

The mechanism of antimicrobial actions of AMPs from sea cucumbers and sea urchins primarily exert their antimicrobial effects by targeting the bacterial membrane, leading to cell death [134]. These peptides are typically cationic, allowing them to bind strongly to the negatively charged bacterial membranes. Once attached, they disrupt membrane integrity through mechanisms such as the barrel-stave, toroidal, and carpet models, resulting in pore formation or membrane disintegration [135,136]. In addition to disrupting membranes, certain AMPs enter microbial cells and interfere with intracellular activities such as DNA replication, protein synthesis, and enzyme function. This dual action, which combines membrane disruption and intracellular targeting, not only improves antimicrobial activity but also lowers the risk of bacteria acquiring resistance [137]. In silico studies have revealed the molecular connections between these peptides and bacterial targets. Molecular docking simulations indicated that sea cucumber peptides may establish hydrogen bonds and hydrophobic interactions with bacterial membrane components, increasing their antibacterial activity [138]. These computational methods have also been utilized to create tailored peptides with greater stability and selectivity (Figure 6).

In addition to these mechanisms, antibiotic-resistant biofilms also pose a huge problem in the treatment of bacterial diseases. Antibiofilm activities have been reported for sea cucumber and sea urchin peptides, which might become potential drugs for chronic infections. For example, coelomocyte lysates from the sea urchin Paracentrotus lividus and sea cucumber Holothuria tubulosa contain AMPs that inhibit biofilm formation in Staphylococcus epidermidis and Staphylococcus aureus at sub-MIC levels [125]. e, Holothuroidin 2 (H2) and its derivative H2d, isolated from H. tubulosa, have shown strong antibiofilm action against Listeria monocytogenes [134]. This feature is particularly useful in food safety and medical device coatings, where biofilm avoidance is vital.

Figure 6 Antimicrobial mechanism of peptides derived from sea urchins and sea cucumbers.

Memory enhancement

Bioactive peptides produced from sea cucumbers can also enhance memory function and modify the hippocampus in an animal model of memory impairment. If left untreated, this memory disorder may develop into Alzheimer disease (AD). Based on this work, mice fed peptides derived from sea cucumbers exhibited modest memory improvement. This memory improvement was demonstrated by analyzing the behavior of the mice, such as by placing the mice in a labyrinth. The brain damage in mice treated with sea cucumber peptides improves; this behavioral trial shows that these peptides have the power to increase and minimize damage to the brain and memory. Measuring acetylcholine levels in the hippocampus, besides other capabilities, these peptides can also increase acetylcholine levels in the hippocampus. Because acetylcholine is not degraded by acetylcholinesterase, high content means that information may be transmitted, thus improving mouse memory [139,140]. It assessed the neuroprotective function of sea cucumber ovum peptide-derived NDEELNK and found its neuroprotective effect by improving acetylcholine levels and reducing AChE activity in PC12 cells. This enhances superoxide dismutase, reduces reactive oxygen species, improves energy metabolism in scopolamine-exerted PC12 cells, and downregulates various signaling proteins. The confirmation study by in silico showed the interaction of AChE involves hydrophobic and hydrogen bonds, bioactive peptides crucial for their activity. The interactions observed through molecular docking confirmed that the binding cavity wall amino acid residues interacted with the active site of NDEELNK peptide from sea cucumber ovum enhance the AChE inhibition effect.

Current challenges and future prospective

Current challenges for bioactive peptides

The main problem with bioactive peptides for drug development is related to stability, delivery, and bioavailability. Oral administration is poor due to the gastrointestinal tract because peptides are easily digested by enzymes and have low permeability across the intestinal epithelium [141,142] (Figure 7). Thus, their oral bioavailability is usually low, which calls for other modes of delivery or strategies to protect them. Bioactive peptides can be absorbed and may exert multi-bioactive functions. Depending on the amino acid sequence, their function can be identified by protein selection, enzymatic hydrolysis, the isolation, and the purification of these amino acids. The final listing was for the biological activities, the peptide sequences, and the functional properties [143]. Microencapsulation is one of the effective techniques to enhance biopeptides’ stability and bioavailability due to environmental factors. Sensitive compounds were enclosed in small capsules in order to minimize the risks and increase their efficiency [144,145]. Microencapsulation can protect the peptides from digestion enzymes, improve the solubility, and increase the dissolution rate of the bioactive compounds. In one study, lutein microparticles with smaller particle sizes showed higher apparent solubility and dissolution rates compared to bigger particles and their physical mixtures [48].

Figure 7 Challenge in the development of bioactive peptides for drug discovery.

The challenge with in vitro-based bioactive peptides is that bioactive peptides tested in vitro are not always active in vivo. This may be due to the digestion or non-absorption of bioactive peptides. This protein is susceptible to extensive hydrolysis in the gastrointestinal tract by stomach, intestine, and brush border peptidases. Consequently, many of the peptides produced do not reach the reabsorption stage in the duodenum and jejunum [146,147]. This suggests that various gastrointestinal proteases, such as pepsin, trypsin chymotrypsin, brush border, and serum peptidases, can affect peptide bonds through endogenous cleavage, resulting in conformational changes and loss of biological function. Most of the blood pressure entering the duodenum and jejunum is not absorbed into the bloodstream. Digestion resistance and absorption resistance, 2 major aspects of bioactive peptide function, should be evaluated prior to further characterization of bioactive peptides in the blood [148].

The challenges in the separation and characterization of bioactive peptides are commonly solved using various chromatographic techniques. However, the isolation and characterization of bioactive peptides is highly problematic and constrained. Bioactive peptides frequently contain short sequences (2 - 6 amino acids). This is a significant obstacle to the current proteomics technology [149]. Small peptides may not be ideal for MS detection because they are frequently simply loaded and it is challenging to acquire adequate fragments [150]. Peptides of less than 6 amino acids are generally not recognized by high-fidelity bioinformatics tools, and peptides are typically recognized by distinct protein sequences, rendering the MS/MS database search methods obsolete. This is caused by AChE inhibitory peptides, which are typically short peptides.

However, small peptides require specialized separation techniques. Traditional RP-HPLC and SEC methods for separating bioactive peptides are unsuitable for small peptides [151]. Another issue in peptide purification and fractionation is related to scale. Peptide properties such as molecular weight, net charge, and hydrophobicity are important parameters to be considered in separation processes for industrial applications [152]. Solid-phase methods and techniques like RP-HPLC are the most commonly used methods in research (laboratory scale), but the problem is that they are expensive.

While generally said to be nontoxic, the studies that are emerging indicate some peptides may cause allergic reactions or are toxic [153]. This therefore means that development must predominantly consider safety assessment. Besides, therapeutic peptides production has its challenges in ensuring consistent quality between batches-an issue that influences their efficacy and safety profiles [147]. Various strategies, including chemical modification, nanocarrier encapsulation, and cell-penetrating peptides, are being developed to enhance stability and bioavailability [154]. The integration of computational tools and artificial intelligence in peptide research offers promising avenues for addressing these challenges, with the potential to accelerate the development of effective peptide-based therapeutics.

Conclusions

Bioactive peptides obtained from Echinozoa, particularly sea cucumbers and sea urchins, have enormous therapeutic potential due to their various biological activity. These peptides have antioxidant, anticancer, antidiabetic, antifatigue, ACE inhibitor, antibacterial, and memory-enhancing effects. Their mechanisms of action include scavenging free radicals, altering critical metabolic pathways, causing apoptosis in cancer cells, controlling blood glucose levels, and decreasing angiotensin-converting enzyme (ACE) activity to control hypertension. Notably, sea cucumber peptides have been shown to increase insulin sensitivity, mitochondrial function, and activate crucial signaling pathways such as NRF2 and AMPK, all of which contribute to their antifatigue and antidiabetic benefits. Similarly, sea urchin peptides have showed potential in inhibiting cancer growth and fighting microbial infections by disrupting membranes and targeting intracellular pathways. Despite these potential bioactivities, there are significant challenges in extracting, purifying, and characterizing these peptides. Peptide breakdown during digestion, limited bioavailability, and challenges in detecting small peptide sequences all limit their medicinal utility. To ensure efficacy and safety, these problems must be addressed through the development of enhanced extraction procedures, new delivery systems, and rigorous in vivo validation.

Future study should focus on overcoming these limitations by refining manufacturing procedures, investigating synergistic effects with current medicines, and performing clinical trials to fully fulfill Echinozoa-derived peptides’ medicinal potential. Their inclusion into functional foods, nutraceuticals, and pharmaceutical items might provide new approaches to controlling chronic illnesses and increasing overall human health. These marine-derived peptides show enormous potential as natural, effective medicines in modern medicine, since they bridge the gap between research and application.

Acknowledgements

This study is part of the research on the exploration of active peptides from Echinozoa in Yogyakarta, Indonesia funded by PDUPT project grant number 193/E5/PG.02.00.PT/2022 and Flagship Research Grant 2024 Universitas Gadjah Mada number 4175/UN1/DITLIT/PT.01.03/2024.

References

[1] A Sibiya, J Jeyavani, J Sivakamavalli, C Ravi, M Divya and B Vaseehara. Bioactive compounds from various types of sea urchin and their therapeutic effects - a review. Regional Studies in Marine Science 2021; 44, 101760.

[2] S Kamat, S Kumar, S Philip and M Kumari. Secondary metabolites from marine fungi: Current status and application. In: A Kumar, LFR Ferreira, M Bilal and M Kumari (Eds.). Microbial biomolecules. Academic Press, Massachusetts, 2023, p. 181-209.

[3] K Anjum, SQ Abbas, N Akhter, BI Shagufta, SAA Shah and SSU Hassan. Emerging biopharmaceuticals from bioactive peptides derived from marine organisms. Chemical Biology & Drug Design 2017; 90(1), 12-30.

[4] SU Kadam, BK Tiwari, C Álvarez and CP O’Donnell. Ultrasound applications for the extraction, identification and delivery of food proteins and bioactive peptides. Trends in Food Science & Technology 2015; 46(1), 60-67.

[5] AA Zaky, J Simal-Gandara, JB Eun, JH Shim and AM Abd El-Aty. Bioactivities, applications, safety, and health benefits of bioactive peptides from food and by-products: A review. Frontiers in Nutrition 2022; 8, 815640.

[6] Z Lu, N Sun, L Dong, Y Gao and S Lin. Production of bioactive peptides from sea cucumber and its potential health benefits: A comprehensive review. Journal of Agricultural and Food Chemistry, 2022; 70(25), 7607-7625.

[7] OA Tokede, JM Gaziano, A Yansane, L Djoussé and TA Onabanjo. Soya products and serum lipids: A meta-analysis of randomised controlled trials. British Journal of Nutrition 2015; 14(6), 831-843.

[8] CH Lee, N Hamdan, BB Nyakuma, SL Wong, KY Wong, H Tan, H Jamaluddin and TH Lee. Purification, identification and molecular docking studies of antioxidant and anti-inflammatory peptides from Edible Bird’s Nest. Food Chemistry 2024; 454, 139797.

[9] EE Montuori, DD Pascale and C Lauritano. Recent discoveries on marine organism immunomodulatory activities. Marine Drugs 2022; 20(7), 422.

[10] JM Pang, YC Huang, SP Sun, YR Pan, CY Shen, MC Kao, RH Wang, LH Wang and KT Lin. Effects of synthetic glucocorticoids on breast cancer progression. Steroids 2020; 164, 108738.

[11] J Cai, X Li, H Du, C Jiang, S Xu and Y Cao. Immunomodulatory significance of natural peptides in mammalians: Promising agents for medical application. Immunobiology 2020; 225(3), 151936.

[12] MJ García-Nebot, I Recio and B Hernández-Ledesma. Antioxidant activity and protective effects of peptide lunasin against oxidative stress in intestinal Caco-2 cells. Food and Chemical Toxicology 2013; 65, 155-161.

[13] X Duan, Y Dong, M Zhang, Z Li, G Bu and F Chen. Identification and molecular interactions of novel ACE inhibitory peptides from rapeseed protein. Food Chemistry 2023; 422, 136085.

[14] M Akbarian, A Khani, S Eghbalpour and VN Uversky. Bioactive peptides: Synthesis, sources, applications, and proposed mechanisms of action. International Journal of Molecular Sciences 2022; 23(3), 1445.

[15] YP Huang, FFG Dias, JMLND Moura and D Barile. A complete workflow for discovering small bioactive peptides in foods by LC-MS/MS: A case study on almonds. Food Chemistry 2021; 369, 130834.

[16] G Nayak, RS Bhuyan and A Sahu. Review on biomedical applications of marine algae-derived biomaterials. Universal Journal of Public Health 2022; 10(1), 15-24.

[17] R Dahiya, S Dahiya, NK Fuloria, S Kumar, R Mourya, SV Chennupati, S Jankie, H Gautam, S Singh, SK Karan, S Maharaj, S Fuloria, J Shrivastava, A Agarwal, S Singh, A Kishor, G Jadon and A Sharma. Natural bioactive thiazole-based peptides from marine resources: Structural and pharmacological aspects. Marine Drugs 2020; 18(6), 329.

[18] D Xu, B Liu, J Wang and Z Zhang. Bibliometric analysis of artificial intelligence for biotechnology and applied microbiology: Exploring research hotspots and frontiers. Frontiers in Bioengineering and Biotechnology 2022; 10, 998298.

[19] RCF Cheung, TB Ng and JH Wong. Marine peptides: Bioactivities and applications. Marine Drugs 2015; 13(7), 4006-4043.

[20] R Sable, P Parajuli and S Jois. Peptides, peptidomimetics, and polypeptides from marine sources: A wealth of natural sources for pharmaceutical applications. Marine Drugs 2017; 15(4), 124.

[21] M Faustino, M Veiga, P Sousa, EM Costa, S Silva and M Pintado. Agro-food byproducts as a new source of natural food additives. Molecules 2019; 24(6), 1056.

[22] TV Ovchinnikova. Structure, function, and therapeutic potential of marine bioactive peptides. Marine Drugs 2019; 17(9), 505.

[23] JM Al-Khayri, W Asghar, S Khan, A Akhtar, H Ayub, N Khalid, FM Alessa and MQ Al-Mssallem. Therapeutic potential of marine bioactive peptides against human immunodeficiency virus: Recent evidence, challenges, and future trends. Marine Drugs 2022; 2(8), 477.

[24] HX Jin, HP Xu, Y Li, QW Zhang and H Xie. Preparation and evaluation of peptides with potential antioxidant activity by microwave assisted enzymatic hydrolysis of collagen from sea cucumber Acaudina molpadioides obtained from Zhejiang Province in China. Marine Drugs 2019; 17(3), 169.

[25] C Wang, B Wang and B Li. Bioavailability of peptides from casein hydrolysate in vitro: Amino acid compositions of peptides affect the antioxidant efficacy and resistance to intestinal peptidases. Food Research International 2015; 81, 188-196.

[26] JJ Holst. Glucagon-like peptide-1: Are its roles as endogenous hormone and therapeutic wizard congruent? Journal of Internal Medicine 2022; 291(5), 557-573.

[27] A Rauf, AA Khalil, M Khan, S Anwar, A Alamri, AM Alqarni, A Alghamdi, F Alshammari, KRR Rengasamy and AM Alqarnie. Can be marine bioactive peptides (MBAs) lead the future of foodomics for human health? Critical Reviews in Food Science and Nutrition 2021; 62(25), 7072-7116.

[28] Y He, T Takei, L Moroder and H Hojo. Unexpected diselenide metathesis in selenocysteine-substituted biologically active peptides. Organic & Biomolecular Chemistry 2024; 22(30), 6108-6114.

[29] YK Leong and JS Chang. Proteins and bioactive peptides from algae: Insights into antioxidant, anti-hypertensive, anti-diabetic and anti-cancer activities. Trends in Food Science & Technology 2024; 145, 104352.

[30] NB Janakiram, A Mohammed and CV Rao. Sea cucumbers metabolites as potent anti-cancer agents. Marine Drugs 2015; 13(5), 2909-2923.

[31] W Zhang, M Al-Wraikata, L Li and Y Liu. Physicochemical properties, antioxidant and antidiabetic activities of different hydrolysates of goat milk protein. Journal of Dairy Science 2024; 107(12), 10174-10189.

[32] I Barkia, L Al‐Haj, A Abdul Hamid, M Zakaria, N Saari and F Zadjali. Indigenous marine diatoms as novel sources of bioactive peptides with antihypertensive and antioxidant properties. International Journal of Food Science & Technology 2018; 54(5), 1514-1522.

[33] SY Lee and SJ Hur. Antihypertensive peptides from animal products, marine organisms, and plants. Food Chemistry 2017; 228, 506-517.

[34] M Lu, A Mishra, C Boschetti, J Lin, Y Liu, H Huang, CF Kaminski, Z Huang, A Tunnacliffe and GSK Schierle. Sea cucumber-derived peptides alleviate oxidative stress in neuroblastoma cells and improve survival in C. elegans exposed to neurotoxic paraquat. Oxidative Medicine and Cellular Longevity 2021; 2021(1), 8842926.

[35] TF Moya Moreira, OH Gonçalves, FV Leimann and RP Ribeiro. Fish protein hydrolysates: Bioactive properties, encapsulation and new technologies for enhancing peptides bioavailability. Current Pharmaceutical Design 2023; 29(11), 824-836.

[36] F Rivero-Pino. Bioactive food-derived peptides for functional nutrition: Effect of fortification, processing and storage on peptide stability and bioactivity within food matrices. Food Chemistry 2022; 406, 135046.

[37] C Xu, R Zhang and Z Wen. Bioactive compounds and biological functions of sea cucumbers as potential functional foods. Journal of Functional Foods 2018; 49, 73-84.

[38] Z Lu, N Sun, L Dong, Y Gao and S Lin. Production of bioactive peptides from sea cucumber and its potential health benerfits: A comprehensive review. Journal of Agricultural and Food Chemistry 2022; 70(25), 7607-7625.

[39] W Wei, XM Fan, SH Jia, XP Zhang, Z Zhang, XJ Zhang, JX Zhang, JX Zhang, YW Zhang and YW Zhang. Sea cucumber intestinal peptide induces the apoptosis of MCF-7 cells by inhibiting PI3K/AKT pathway. Frontiers in Nutrition 2021; 8, 763692.

[40] TRL Senadheera, A Hossain, D Dave and F Shahidi. Antioxidant and ACE-inhibitory activity of protein hydrolysates produced from atlantic sea cucumber (Cucumaria frondosa). Molecules 2023; 28(13), 5263.

[41] X Zhou, C Wang and A Jiang. Antioxidant peptides isolated from sea cucumber Stichopus japonicus. European Food Research and Technology 2012; 234(3), 441-447.

[42] N Kabeya, A Sanz-Jorquera, S Carboni, A Davie, A Oboh and O Monroig. Biosynthesis of polyunsaturated fatty acids in sea urchins: Molecular and functional characterisation of 3 fatty acyl desaturases from Paracentrotus lividus (Lamark 1816). PLos One 2017; 12(1), e0169374.

[43] B Zhu, X Dong, D Zhou, Y Gao, J Yang, D Li, X Zhao, T Ren, W Ye, H Tan, H Wu and C Yu. Physicochemical properties and radical scavenging capacities of pepsin-solubilized collagen from sea cucumber Stichopus japonicus. Food Hydrocolloids 2012; 28(1), 182-188.

[44] PX Gong, BK Wang, YC Wu, QY Li, BW Qin and HJ Li. Release of antidiabetic peptides from Stichopus japonicas by simulated gastrointestinal digestion. Food Chemistry 2020; 315, 126273.

[45] TL Wargasetia, H Ratnawati, N Widodo and MH Widyananda. Bioinformatics study of sea cucumber peptides as antibreast cancer through inhibiting the activity of overexpressed protein (EGFR, PI3K, AKT1, and CDK4). Cancer Informatics 2021; 20, 11769351211031864.

[46] X Du, F Lian, Y Li, D Li, D Wu, Q Feng, Z Feng, Y Li, G Bu, F Meng, X Cao, Z Chen and X Zeng. Peptides from Colochirus robustus enhance immune function via activating CD3ζ-and ZAP-70-mediated signaling in C57BL/6 mice. International Journal of Molecular Sciences 2017; 18(10), 2110.

[47] MS Vishkaei, A Ebrahimpour, A Abdul-Hamid, A Ismail and N Saari. Angiotensin-I converting enzyme (ACE) inhibitory and antihypertensive effect of protein hydrolysate from Actinopyga lecanora (Sea cucumber) in rats. Marine Drugs 2016; 14(10), 176.

[48] P Wang, D Wang, J Hu, BK Tan, Y Zhang and S Lin. Natural bioactive peptides to beat exercise-induced fatigue: a review. Food Bioscience 2021; 43, 101298.

[49] WK Amakye, C Hou, L Xie, X Lin, N Gou, E Yuan and J Ren. 2021. Bioactive anti-aging agents and the identification of new antioxidant soybean peptides. Food Bioscience 2021; 42, 101194.

[50] R Pangestuti and Z Arifin. Medicinal and health benefit effects of functional sea cucumbers. Journal of Traditional and Complementary Medicine 2017; 8(3), 341-351.

[51] D Li, L Li, T Xu, T Wang, J Ren, X Liu and Y Li. Effect of low molecular weight oligopeptides isolated from sea cucumber on diabetic wound healing in db/db mice. Marine Drugs 2018; 16(1), 16-22.

[52] C Cui, P Wang, N Cui, S Song, H Liang and A Ji. Sulfated polysaccharide isolated from the sea cucumber stichopus jaonicas promotes the SDF-1α/CXCR4 axis-induced NSC migration via the PI3K/Akt/FOXO3a, ERK/MAPK, and NF-κB signaling pathways. Neuroscience Letters 2016; 616, 57-64.

[53] S Wen, K Zhang, Y Li, J Fan, C Ziming, J Zhang, H Wang and L Wang. A self-assembling peptide targeting VEGF receptors to inhibit angiogenesis. Chinese Chemical Letters 2020; 31(12), 3153-3157.

[54] J Mildenberger, M Remm and M Atanassova. Self-assembly potential of bioactive peptides from Norwegian sea cucumber Parastichopus tremulus for development of functional hydrogels. LWT 2021; 148, 111678.

[55] Z Lu, N Sun, L Dong, Y Gao and S Lin. Production of bioactive peptides from sea cucumber and its potential health benefits: A comprehensive review. Journal of Agricultural and Food Chemistry 2022; 70(25), 7607-7625.

[56] MWFS Macedo, NB Cunha, JA Carneiro, RA Costa, SA Alencar, MH Cardoso, OL Franco and SC Dias. Marine organisms as a rich source of biologically active peptides. Frontiers in Marine Science 2021; 8, 667764.

[57] S Heffernan, L Giblin and N O’Brien. Assessment of the biological activity of fish muscle protein hydrolysates using in vitro model systems. Food Chemistry 2021; 359, 129852.

[58] S El Hajj, R Irankunda, JAC Echavarría, P Arnoux, C Paris, L Stefan, C Gaucher, S Boschi-Muller and L Canabady-Rochelle. Metal-chelating activity of soy and pea protein hydrolysates obtained after different enzymatic treatments from protein isolates. Food Chemistry 2022; 405, 134788.

[59] S Aggarwal, AM Mohite and N Sharma. The maturity and ripeness phenomenon with regard to the physiology of fruits and vegetables: A review. Bulletin of the Transilvania University of Brasov 2018; 11(60), 77-88.

[60] MB Mansour, R Balti, V Ollivier, HB Jannet, F Chaubet and RM Maaroufi. Characterization and anticoagulant activity of a fucosylated chondroitin sulfate with unusually procoagulant effect from sea cucumber. Carbohydrate Polymers 2017; 174, 760-771.

[61] A Navvabi, A Homaei, S Khademvatan, MHK Ansari and M Keshavarz. Combination of TiO₂ nanoparticles and Echinometra mathaeis gonad extracts: In vitro and in vivo scolicidal activity against hydatid cysts. Biocatalysis and Agricultural Biotechnology 2019; 22, 101432.

[62] Y Hou, A Carne, M McConnell, AA Bekhit, S Mros, K Amagase and AEDA Bekhit. In vitro antioxidant and antimicrobial activities, and in vivo anti-inflammatory activity of crude and fractionated PHNQs from sea urchin (Evechinus chloroticus). Food Chemistry 2020; 316, 126339.

[63] P Francis and K Chakraborty. Antioxidant and anti-inflammatory cembrane-type diterpenoid from Echinoidea sea urchin Stomopneustes variolaris attenuates pro-inflammatory 5-lipoxygenase. Medicinal Chemistry Research 2020; 29, 656-664.

[64] R Yamamoto, H Minami, H Matsusaki, M Sakashita, N Morita, O Nishimiya and N Tsutsumi. Consumption of the edible sea urchin Mesocentrotus nudus attenuates body weight gain and hepatic lipid accumulation in mice. Journal of Functional Foods 2018; 47, 40-47.

[65] NV Ageenko, KV Kiselev and NA Odintsova. Quinoid pigments of sea urchins Scaphechinus mirabilis and Strongylocentrotus intermedius: Biological activity and potential applications. Marine Drugs 2022; 20(10), 611.

[66] AM Soliman, AS Mohamed and MAS Marie. Echinochrome pigment attenuates diabetic nephropathy in the models of type 1 and type 2 diabetes. Diabetes Mellitus 2016; 19, 464-470.

[67] DM Moreno-García, M Salas-Rojas, E Fernández-Martínez, MDR López-Cuellar, CG Sosa-Gutierrez1, A Peláez-Acero1, N Rivero-Perez1, A Zaragoza-Bastida1 and D Ojeda-Ramírez​​1. Sea urchins: An update on their pharmacological properties. PeerJ 2022; 10, e13606.

[68] A Salimi, A Motallebi, M Ayatollahi, E Seydi, AR Mohseni, M Nazemi and J Pourahmad. Selective toxicity of persian gulf sea cucumber holothuria parva on human chronic lymphocytic leukemia b lymphocytes by direct mitochondrial targeting. Environmental Toxicology 2017; 32, 1158-1169.

[69] NY Kim, WY Choi, SJ Heo, DH Kang and HY Lee. Anti-skin cancer activities of Apostichopus japonicus extracts from low-temperature ultrasonification process. Journal of Healthcare Engineering 2017; 2017(1), 6504890.

[70] X Liu, J Xu, Y Xue, Z Gao, Z Li, K Leng, J Wang, C Xue and Y Wang. Sea cucumber cerebrosides and long-chain bases from Acaudina molpadioides protect against high fat diet-induced metabolic disorders in mice. Food & Function 2015; 6, 3428-3436.

[71] AR El Barky, SA Hussein, AA Alm-Eldeen, YA Hafez and TM Mohamed. Antidiabetic activity of holothuria thomasi saponin. Biomedicine & Pharmacotherapy 2016; 84, 1472-1487.

[72] TH Nguyen and SM Kim. α-Glucosidase inhibitory activities of fatty acids purified from the internal organ of sea cucumber Stichopus japonicas. Journal of Food Science 2015; 80, 841-847.

[73] H Che, L Du, P Cong, S Tao, N Ding, F Wu, C Xue, J Xu and Y Wang. Cerebrosides from sea cucumber protect against oxidative stress in SAMP8 mice and PC12 cells. Journal of Medical Food 2017; 20, 392-402.

[74] A Shakouri, MR Shoushizadeh and F Nematpour. Antimicrobial activity of sea cucumber (Stichopus variegatus) body wall extract in Chabahar Bay, Oman Sea. Jundishapur Journal of Natural Pharmaceutical Products 2017; 12(1), e32422.

[75] J Mou, C Wang, W Li and J Yang. Purification, structural characterization and anticoagulant properties of fucosylated chondroitin sulfate isolated from Holothuria mexicana. International Journal of Biological Macromolecules 2017; 98, 208-215.

[76] J Zhang, M Li, G Zhang, YU Tian, F Kong, S Xiong, S Zhao, D Jia, A Manyande and H Du. Identification of novel antioxidant peptides from snakehead (Channa argus) soup generated during gastrointestinal digestion and insights into the anti-oxidation mechanisms. Food Chemistry 2021; 337, 127921.

[77] B Xu, Q Dong, C Yu, H Chen, Y Zhao, B Zhang, P Yu and M Chen. Advances in research on the activity evaluation, mechanism and structure-activity relationships of natural antioxidant peptides. Antioxidants 2024; 13(4), 479.

[78] Y Zhu, F Lao, X Pan and J Wu. Food protein-derived antioxidant peptides: Molecular mechanism, stability and bioavailability. Biomolecules 2022; 12(11), 1622.

[79] CW Gruber. Plant-derived peptides: (Neglected) natural products for drug discovery. Planta Medica 2024; 90(7-8), 627-630.

[80] A Moayedi, L Mora, MC Aristoy, M Hashemi, M Safari and F Toldrá. ACE-inhibitory and antioxidant activities of peptide fragments obtained from tomato processing by-products fermented using Bacillus subtilis: Effect of amino acid composition and peptides molecular mass distribution. Applied Biochemistry and Biotechnology 2016; 181(1), 48-64.

[81] M Tian, B Fang, L Jiang, H Guo, JY Cui and F Ren. Structure-activity relationship of a series of antioxidant tripeptides derived from β-Lactoglobulin using QSAR modeling. Dairy Science & Technology 2015; 95(4), 451-463.

[82] V D’Opazo, J Calpe, L Escrivá, TM Nazareth, G Meca and C Luz. Identification and evaluation of antioxidant activity of bioactive casein-derived peptides during in vitro digestion and transepithelial transport in Caco-2 cells. Food Bioscience 2023; 53, 102763.

[83] Y Ma, Y Wu and L Li. Relationship between primary structure or spatial conformation and functional activity of antioxidant peptides from Pinctada fucata. Food Chemistry 2018; 264, 108-117.

[84] TB Zou, TP He, HB Li, HW Tang and EQ Xia. The structure-activity relationship of the antioxidant peptides from natural proteins. Molecules 2016; 21, 72.

[85] L Lin, K Yang, L Zheng, M Zhao, W Sun, Q Zhu and S Liu. Anti-aging effect of sea cucumber (Cucumaria frondosa) hydrolysate on fruit flies and d-galactose-induced aging mice. Journal of Functional Foods 2018; 47, 11-18.

[86] A Hernández-Jabalera, I Cortés-Giraldo, G Dávila-Ortíz, J Vioque, M Alaiz, J Girón-Calle, C Megías and C Jiménez-Martínez. Influence of peptides - phenolics interaction on the antioxidant profile of protein hydrolysates from Brassica napus. Food Chemistry 2014; 178, 346-357.

[87] S Zhao, Q Cheng, Q Peng, X Yu, X Yin, M Liang, CW Ma, Z Huang and W Jia. Antioxidant peptides derived from the hydrolyzate of purple sea urchin (Strongylocentrotus nudus) gonad alleviate oxidative stress in Caenorhabditis elegans. Journal of Functional Foods 2018; 48, 594-604.

[88] Q Wang, Y Huang, C Qin, M Liang, X Mao, S Li, Y Zou, W Jia, H Li, CW Ma and Z Huang. Bioactive peptides from Angelica sinensis protein hydrolysate delay senescence in Caenorhabditis elegans through antioxidant activity. Oxidative Medicine and Cellular Longevity 2016; 1, 8956981.

[89] Y Wu, J Yang, C Xu, Q Li, Y Ma, S Zhao, J Zhuang, F Shen, Q Wang, F Feng and X Zhang. Sea cucumber (Acaudina leucoprocta) peptides extended the lifespan and enhanced antioxidant capacity via DAF-16/DAF-2/SOD-3/OLD-1/PEPT-1 in Caenorhabditis elegans. Frontiers in Nutrition 2022; 9, 1065145.

[90] WH Shang, Y Tang, SY Su, JR Han, JN Yan, HT Wu and BW Zhu. In silico assessment and structural characterization of antioxidant peptides from major yolk protein of sea urchin Strongylocentrotus nudus. Food & Function 2018; 9(12), 6435-6443.

[91] C Doungapai, T Siriwoharn, Y Malila, N Autsavapromporn, S Makkhun, S Yarnpakdee and S Wangtueai. UV-B protective and antioxidant activities of protein hydrolysate from sea cucumber (Holothuria scabra) using enzymatic hydrolysis. Frontiers in Marine Science 2022; 9, 892255.

[92] R Safari and Z Yaghoubzadeh. Antioxidant activity of bioactive peptides extracted from sea cucumber (Holothuria leucospilata). International Journal of Peptide Research and Therapeutics 2020; 26(4), 2393-2398.

[93] K Guo, L Su, Y Wang, H Liu, J Lin, P Cheng, X Yin, M Liang, Q Wang and Z Huang. Antioxidant and anti-aging effects of a sea cucumber protein hydrolyzate and bioinformatic characterization of its composing peptides. Food & Function 2020; 11(6), 5004-5016.

[94] H Yang, Q Zhang, B Zhang, Y Zhao and N Wang. Potential active marine peptides as anti-aging drugs or drug candidates. Marine Drugs 2023; 21(3), 144.

[95] H Yang, Q Zhang, B Zhang, Y Zhao and N Wang. Antimicrobial peptides with anticancer activity: Today status, trends and their computational design. Archives of Biochemistry and Biophysics 2022; 733, 109484.

[96] Q Liang, F Ahmed, M Zhang, N Sperou, CMM Franco, Q Feng and W Zhang. In vivo and clinical studies of sea cucumber-derived bioactives for human health and nutrition from 2012-2021. Frontiers in Marine Science 2022; 9, 917857.

[97] JA Pérez-Vega, L Olivera-Castillo, JA Gómez-Ruiz and B Hernández-Ledesma. Release of multifunctional peptides by gastrointestinal digestion of sea cucumber (Isostichopus badionotus). Journal of Functional Foods 2013; 5(2), 869-877.

[98] OY Althunibat, BH Ridzwan, M Taher, JM Daud, SJA Ichwan and H Qaralleh. Antioxidant and cytotoxic properties of 2 sea cucumbers, Holothuria edulis Lesson and Stichopus horrens Selenka. Acta Biologica Hungarica 2013; 64(1), 10-20.

[99] T Sugawara, N Zaima, A Yamamoto, S Sakai, R Noguchi and T Hirata. Isolation of sphingoid bases of sea cucumber cerebrosides and their cytotoxicity against human colon cancer cells. Bioscience, Biotechnology, and Biochemistry 2006; 70(12), 2906-2912.

[100] R Ru, Y Guo, J Mao, Z Yu, W Huang, X Cao, H Hu, M Meng and L Yuan. Cancer cell inhibiting sea cucumber (Holothuria leucospilota) protein as a novel anti-cancer drug. Nutrients 2022; 14(4), 786.

[101] W Wijesinghe, YJ Jeon, P Ramasamy, MEA Wahid and CS Vairappan. Anticancer activity and mediation of apoptosis in human HL-60 leukaemia cells by edible sea cucumber (Holothuria edulis) extract. Food Chemistry 2013; 139(1-4), 326-331.

[102] MH Widyananda, SK Pratama, RS Samoedra, FN Sari, VD Kharisma, ANM Ansori and Y Atonius. Molecular docking study of sea urchin (Arbacia lixula) peptides as multi-target inhibitor for non-small cell lung cancer (NSCLC) associated proteins. Journal of Pharmacy & Pharmacognosy Research 2021; 9(4), 484-496.

[103] H Cui, W Han, J Zhang, Z Zhang and X Su. Advances in the regulatory effects of bioactive peptides on metabolic signaling pathways in tumor cells. Journal of Cancer 2019; 10(11), 2425.

[104] X Lu, M Wang, H Yue, X Feng, Y Tian, C Xue, T Zhang and Y Wang. Novel peptides from sea cucumber intestines hydrolyzed by neutral protease alleviate exercise-induced fatigue via upregulating the glutaminemediated Ca²⁺ /Calcineurin signaling pathway in mice. Journal of Food Science 2024; 89(3), 1727-1738.

[105] Q Wang, J Shi, H Zhong, J Zhuang, J Zhang, J Wang, X Zhang and F Feng. High-degree hydrolysis sea cucumber peptides improve exercise performance and exert antifatigue effect via activating the NRF2 and AMPK signaling pathways in mice. Journal of Functional Foods 2021; 86, 104677.

[106] X Wang, Z Ding, Y Zhao, S Prakash, W Liu, J Han and Z Wang. Effects of lutein particle size in embedding emulsions on encapsulation efficiency, storage stability, and dissolution rate of microencapsules through spray drying. LWT 2021; 146, 111430.

[107] L Jia, L Wang, C Liu, Y Liang and Q Lin. Bioactive peptides from foods: Production, function, and application. Food & Function 2021; 12(16), 7108-7125.

[108] J Yan, J Zhao, R Yang and W Zhao. Bioactive peptides with antidiabetic properties: A review. International Journal of Food Science & Technology 2019; 54(6), 1909-1919.

[109] C Gonzalez-Lopez and BS Wojeck. Role of metformin in the management of type 2 diabetes: Recent advances. Polish Archives of Internal Medicine 2023; 133(6), 16511-16511.

[110] RG Solstad, C Li, J Isaksson, J Johansen, J Svenson, K Stensvåg and T Haug. Novel antimicrobial peptides EeCentrocins 1, 2 and EeStrongylocin 2 from the edible sea urchin Echinus esculentus have 6-Br-Trp post-translational modifications. PLos One 2016; 11(3), e0151820.

[111] F Jahandideh and J Wu. A review on mechanisms of action of bioactive peptides against glucose intolerance and insulin resistance. Food Science and Human Wellness 2022; 11(6), 1441-1454.

[112] P Antony and R Vijayan. Bioactive peptides as potential nutraceuticals for diabetes therapy: A comprehensive review. International Journal of Molecular Sciences 2021; 22(16), 9059.

[113] H Admassu, MAA Gasmalla, R Yang and W Zhao. Bioactive peptides derived from seaweed protein and their health benefits: Antihypertensive, antioxidant, and antidiabetic properties. Journal of Food Science 2018; 83(1), 6-16.

[114] ECY Li-Chan. Bioactive peptides and protein hydrolysates: Research trends and challenges for application as nutraceuticals and functional food ingredients. Current Opinion in Food Science 2015; 1, 28-37.

[115] W Zheng, E Tian, Z Liu, C Zhou, P Yang and E Tian. Small molecule angiotensin converting enzyme inhibitors: A medicinal chemistry perspective. Frontiers in Pharmacology 2022; 13, 968104.

[116] M Memarpoor-Yazdi, H Zare-Zardini, N Mogharrab and L Navapour. Purification, characterization and mechanistic evaluation of angiotensin converting enzyme inhibitory peptides derived from Zizyphus jujuba fruit. Scientific Reports 2020; 10(1), 3976.

[117] C Zhong, LC Sun, LJ Yan, YC Lin, GM Li and MJ Cao. Production, optimisation and characterisation of angiotensin converting enzyme inhibitory peptides from sea cucumber (Stichopus japonicus) gonad. Food & Function 2018; 9(1), 594-603.

[118] Y Wang, S Chen, W Shi, S Liu, X Chen, N Pan, X Wang, Y Su and Z Liu. Targeted affinity purification and mechanism of action of Angiotensin-Converting Enzyme (ACE) inhibitory peptides from sea cucumber gonads. Marine Drugs 2024; 22(2), 90.

[119] AS Dewi, G Patantis, YN Fawzya, HE Irianto and S Sa’diah. Angiotensin-converting enzyme (ace) inhibitory activities of protein hydrolysates from Indonesian sea cucumbers. International Journal of Peptide Research and Therapeutics 2020; 26(4), 2485-2493.

[120] ZY Liu, D Chen, YC Su and MY Zeng. Optimization of hydrolysis conditions for the production of the angiotensin-I converting enzyme inhibitory peptides from sea cucumber collagen hydrolysates. Journal of Aquatic Food Product Technology 2011; 20(2), 222-232.

[121] MZ Abedin, AA Karim, CY Gan, FC Ghazali, Z Barzideh, W Zzaman and ISM Zaidul. Identification of angiotensin I converting enzyme inhibitory and radical scavenging bioactive peptides from sea cucumber (Stichopus vastus) collagen hydrolysates through optimization. International Food Research Journal 2015; 22(3), 1074.

[122] EC Alvarenga, MC Fonseca, CC Carvalho, RM Florentino, A França, E Matias, PB Guimarães, C Batista,V Freire, AK Carmona, JB Pesquero, AMD Paula, G Foureaux and MD Fatima Leite. Angiotensin converting enzyme regulates cell proliferation and migration. PLos One 2019; 11(12), e0165371.

[123] K Bush, PR Henry and DS Slusarchyk. Muraceins - muramyl peptides produced by Nocardia orientalis as angiotensin-converting enzyme inhibitors. I. Taxonomy, fermentation and biological properties. The Journal of Antibiotics 1984; 37(4), 330-335.

[124] M Mahlapuu, J Håkansson, L Ringstad and C Björn. Antimicrobial peptides: An emerging category of therapeutic agents. Frontiers in Cellular and Infection Microbiology 2016; 6(S3), 235805.

[125] C Li, T Haug, OB Styrvold, TØ Jørgensen and K Stensvåg. Strongylocins, novel antimicrobial peptides from the green sea urchin, Strongylocentrotus droebachiensis. Developmental & Comparative Immunology 2008; 32(12), 1430-1440.

[126] XH Shang, XY Liu, JP Zhang, Y Gao, BH Jiao and H Zheng. Traditional Chinese medicine - sea urchin. Mini-Reviews in Medicinal Chemistry 2014; 14(6), 537-542.

[127] JM Sciani, AK Emerenciano, JRMC Silva and DC Pimenta. Initial peptidomic profiling of Brazilian sea urchins: Arbacia lixula, Lytechinus variegatus and Echinometra lucunter. Journal of Venomous Animals and Toxins Including Tropical Diseases 2916; 22(1), 17.

[128] RG Solstad and P James. Observations from the hydrolysis of the green sea urchins (Strongylocentrotrus droebachiensis). Global Challenges 2023; 7(5), 2200078.

[129] RG Solstad, C Johansen, K Stensvåg, MB Strøm and T Haug. Structure-activity relationship studies of shortened analogues of the antimicrobial peptide eecentrocin 1 from the sea urchin Echinus esculentus. Journal of Peptide Science 2020; 26(2), e3233.

[130] S Mashjoor and M Yousefzadi. Holothurians antifungal and antibacterial activity to human pathogens in the Persian Gulf. Journal de Mycologie Médicale 2016; 27(1), 46-56.

[131] L Cong, W Liang, Y Wu, C Li, Y Chang, L Dong, W Song and J Ma. High-level soluble expression of the functional peptide derived from the C-terminal domain of the sea cucumber lysozyme and analysis of its antimicrobial activity. Electronic Journal of Biotechnology 2014; 17(6), 2802-2886.

[132] KA Beauregard, NT Truong, H Zhang, W Lin and G Beck. The detection and isolation of a novel antimicrobial peptide from the echinoderm Cucumaria frondosa. In: G Beck, M Sugumaran and EL Cooper (Eds.). Phylogenetic perspectives on the vertebrate immune system, Springer, Boston, p. 55-62.

[133] MG Cusimano, A Spinello, G Barone, D Schillaci, S Cascioferro, A Magistrato, B Parrino and M Vitale. A synthetic derivative of antimicrobial peptide holothuroidin 2 from mediterranean sea cucumber (Holothuria tubulosa) in the control of Listeria monocytogenes. Marine Drugs 2019; 17(3), 159.

[134] QY Zhang, ZB Yan, YM Meng, XY Hong, G Shao, JJ Ma, XR Cheng, J Liu, J Kang and CY Fu. Antimicrobial peptides: Mechanism of action, activity and clinical potential. Military Medical Research 2021; 8(1), 1-25.

[135] GS Dijksteel, MMW Ulrich, E Middelkoop and BKHL Boekema. Review: Lessons learned from clinical trials using antimicrobial peptides (AMPs). Frontiers in Microbiology 2021; 12(837), 616979.

[136] JAF Corrêa, AG Evangelista, TDM Nazareth and FB Luciano. Fundamentals on the molecular mechanism of action of antimicrobial peptides. Materialia 2019; 8, 100494.

[137] M Drayton, JP Deisinger, KC Ludwig, N Raheem, A Müller, T Schneider and SK Straus. Host defense peptides: Dual antimicrobial and immunomodulatory action. International Journal of Molecular Sciences 2021; 22(20), 11172.

[138] M Ouassaf, L Bourougaa, SH Al-Mijalli, EM Abdallah, AR Bhat and SMA Kawsar. Marine-derived compounds as potential inhibitors of Hsp90 for anticancer and antimicrobial drug development: A Comprehensive in silico study. Molecules 2023; 28(24), 8074.

[139] X Xu, R Liang, D Li, C Jiang and S Lin. Evaluation of sea cucumber peptides-assisted memory activity and acetylation modification in hippocampus of test mice based on scopolamine-induced experimental animal model of memory disorder. Journal of Functional Foods 2020; 68, 103909.

[140] Y Zhao, Y Dong, Q Ge, P Cui, N Sun and S Lin. Neuroprotective effects of NDEELNK from sea cucumber ovum against scopolamine-induced PC12 cell damage through enhancing energy metabolism and upregulation of the PKA/BDNF/NGF signaling pathway. Food & Function 2021; 12(17), 7676-7687.

[141] J Pei, X Gao, D Pan, Y Hua, J He, Z Liu and Y Dang. Advances in the stability challenges of bioactive peptides and improvement strategies. Current Research in Food Science 2022; 5, 2162-2170.

[142] Y Yang, R Zhou, Y Wang, Y Zhang, J Yu and Z Gu. Recent advances in oral and transdermal protein delivery systems. Angewandte Chemie 2023; 135(10), e202214795.

[143] M Barati, F Javanmardi, SMH Mousavi Jazayeri, M Jabbari, J Rahmani, F Barati, H Nickho, SH Davoodi, N Roshanravan and AM Khaneghah. Techniques, perspectives, and challenges of bioactive peptide generation: A comprehensive systematic review. Comprehensive Reviews in Food Science and Food Safety 2018; 19(4), 1488-1250.

[144] K Huang, Y Yuan and X Baojun. A critical review on the microencapsulation of bioactive compounds and their application. Food Reviews International 2023; 39(5), 2594-2634.

[145] C Yan and SR Kim. Microencapsulation for pharmaceutical applications: A review. ACS Applied Bio Materials 2024; 7(2), 692-710.

[146] P Chanphai and HA Tajmir-Riahi. Trypsin and trypsin inhibitor bind milk beta-lactoglobulin: Protein-protein interactions and morphology. International Journal of Biological Macromolecules 2017; 96, 754-758.

[147] M Foltz, PCVD Pijl and GS Duchateau. Current in vitro testing of bioactive peptides is not valuable. Journal of Nutrition 2010; 140(1), 117-118.

[148] J Chen, Y Liu, G Wang, S Sun, R Liu, B Hong, R Gao and K Bai. Processing optimization and characterization of angiotensin-i-converting enzyme inhibitory peptides from lizardfish (Synodus macrops) scale gelatin. Marine Drugs 2018; 16(7), 228.

[149] S Piovesana, AL Capriotti, C Cavaliere, GL Barbera, CM Montone, R Zenezini Chiozzi and A Laganà. Recent trends and analytical challenges in plant bioactive peptide separation, identification and validation. Analytical and Bioanalytical Chemistry 2018; 410(15), 3425- 3444.

[150] AB Nongonierma and RJ FitzGerald. Strategies for the discovery and identification of food protein-derived biologically active peptides. Trends in Food Science & Technology 2017; 69, 289-305.

[151] EC Li-Chan. Bioactive peptides and protein hydrolysates: Research trends and challenges for application as nutraceuticals and functional food ingredients. Current Opinion in Food Science 2017; 1, 28-37.

[152] CG Rizzello, D Tagliazucchi, E Babini, GS Rutella, DLT Saa and A Gianotti. Bioactive peptides from vegetable food matrices: Research trends and novel biotechnologies for synthesis and recovery. Journal of Functional Foods 2016; 27, 549-569.