Purification and Antioxidant Property of Antioxidative Oligopeptide from Short-Necked Clam (Ruditapes philippinarum) Hydrolysate In Vitro

Clam peptides: Preparation, flavor properties, health benefits, and safety risks

Bioactive peptides derived from food proteins have attracted attention for their potential roles in functional foods and pharmaceuticals. Clams, renowned for their protein content and essential amino acids critical to human health, represent a promising source for bioactive peptide production. Recent studies have extensively explored the preparation methods, flavor profiles, and health benefits of clam peptides (CPs). However, there is still a lack of a comprehensive review on the current status of CPs development. This review revealed that enzymatic hydrolysis is the predominant methods for CPs production, which is a potential resource for discovering umami peptides. CPs exhibit diverse bioactivities, including antioxidative, antibacterial, ACE inhibitory, immunomodulatory, and anticancer activities. However, the potential presence of heavy metals, pathogenic bacteria, and allergens in raw materials underscores the need for stringent safety evaluations. In the future, production technology, in vivo fate, health efficacy mechanisms and safety will be interesting directions for CPs research.

Phalloidin fluorescence and confocal microscopy reveal the musculature development of clam Ruditapes philippinarum

Knowledge of early development in bivalves is of great importance to understand the function of animal organ systems and the evolution of phenotypic diversity. Manila clam (Ruditapes philippinarum) is an economically important bivalve living in marine intertidal zones. To determine the pattern of muscle development in the clams, we investigate the characteristics of musculature development utilizing phalloidin staining and confocal microscopy. Myofilaments first appear at the early trochophore stage, and gradually become orderly arranged during the transition from trochophore to veliger. For veliger, larval muscle system is mainly composed of dorsal velum retractors, medio-dorsal velum retractors, ventral velum retractors, ventral larval retractors and anterior and posterior adductor muscles. After metamorphosis, the muscle system of late veliger has been reconstructed, showing the irreversible shrink of velum retractor muscles, the rapid growth of wedge-shaped foot and mantle margins. One of the most striking changes in settled spats is the development of sophisticated architecture of foot musculature, which consists of transverse pedal muscles, anterior foot retractor and posterior foot retractor. These findings will not only provide the basis to understand the dynamic pattern of myogenesis in the burrowing bivalves, but also provide valuable information for comparative analysis of muscle development among bivalves.

Barrel Jellyfish (Rhizostoma pulmo) as Source of Antioxidant Peptides

The jellyfish Rhizostoma pulmo, Macrì 1778 (Cnidaria, Rhizostomae) undergoes recurrent outbreaks in the Mediterranean coastal waters, with large biomass populations representing a nuisance or damage for marine and maritime activities. A preliminary overview of the antioxidant activity (AA) of R. pulmo proteinaceous compounds is provided here based on the extraction and characterization of both soluble and insoluble membrane-fractioned proteins, the latter digested by sequential enzymatic hydrolyses with pepsin and collagenases. All jellyfish proteins showed significant AA, with low molecular weight (MW) proteins correlated with greater antioxidant activity. In particular, collagenase-hydrolysed collagen resulted in peptides with MW lower than 3 kDa, ranging 3⁻10 kDa or 10⁻30 kDa, with AA inversely proportional to MW. No cytotoxic effect was detected on cultured human keratinocytes (HEKa) in a range of protein concentration 0.05⁻20 μg/mL for all tested protein fractions except for soluble proteins higher than 30 kDa, likely containing the jellyfish venom compounds. Furthermore, hydrolyzed jellyfish collagen peptides showed a significantly higher AA and provided a greater protective effect against oxidative stress in HEKa than the hydrolyzed collagen peptides from vertebrates. Due to a high reproductive potential, jellyfish may represent a potential socioeconomic opportunity as a source of natural bioactive compounds, with far-reaching beneficial implications. Eventually, improvements in processing technology will promote the use of untapped marine biomasses in nutraceutical, cosmeceutical, and pharmaceutical fields, turning marine management problems into a more positive perspective.

Identification and characterization of antioxidant peptides from hydrolysate of blue-spotted stingray and their stability against thermal, pH and simulated gastrointestinal digestion treatments

This study was conducted to identify and characterize antioxidant peptides from the alcalase hydrolysate of the blue-spotted stingray. Purification steps guided by ABTS cation radical (ABTS+) scavenging assay and de novo peptide sequencing produced two peptides, WAFAPA (661.3224 Da) and MYPGLA (650.3098 Da). WAFAPA (EC50 = 12.6 µM) had stronger antioxidant activity than glutathione (EC50 = 13.7 µM) and MYPGLA (EC50 = 19.8 µM). Synergism between WAFAPA and MYPGLA was detected. WAFAPA and MYPGLA surpassed carnosine in their ability to suppress H2O2-induced lipid oxidation. The peptides protected plasmid DNA and proteins from Fenton's reagent-induced oxidative damage. Thermal (25-100 °C) and pH 3-11 treatments did not alter antioxidant activity of the peptides. MYPGLA maintained its antioxidant activity after simulated gastrointestinal digestion, whereas WAFAPA showed a partial loss. The two peptides may have potential applications as functional food ingredients or nutraceuticals, whether used singly or in combination.

Enzyme-Assisted Discovery of Antioxidant Peptides from Edible Marine Invertebrates: A Review

Marine invertebrates, such as oysters, mussels, clams, scallop, jellyfishes, squids, prawns, sea cucumbers and sea squirts, are consumed as foods. These edible marine invertebrates are sources of potent bioactive peptides. The last two decades have seen a surge of interest in the discovery of antioxidant peptides from edible marine invertebrates. Enzymatic hydrolysis is an efficient strategy commonly used for releasing antioxidant peptides from food proteins. A growing number of antioxidant peptide sequences have been identified from the enzymatic hydrolysates of edible marine invertebrates. Antioxidant peptides have potential applications in food, pharmaceuticals and cosmetics. In this review, we first give a brief overview of the current state of progress of antioxidant peptide research, with special attention to marine antioxidant peptides. We then focus on 22 investigations which identified 32 antioxidant peptides from enzymatic hydrolysates of edible marine invertebrates. Strategies adopted by various research groups in the purification and identification of the antioxidant peptides will be summarized. Structural characteristic of the peptide sequences in relation to their antioxidant activities will be reviewed. Potential applications of the peptide sequences and future research prospects will also be discussed.