Bioactivity of Marine-Derived Peptides and Proteins: A Review

The marine environment, covering over 70% of the Earth's surface, serves as a reservoir of bioactive molecules, including peptides and proteins. Due to the unique and often extreme marine conditions, these molecules exhibit distinctive structural features and diverse functional properties, making them promising candidates for therapeutic applications. Marine-derived bioactive peptides, typically consisting of 3 to 40 amino acid residues-though most commonly, 2 to 20-are obtained from parent proteins through chemical or enzymatic hydrolysis, microbial fermentation, or gastrointestinal digestion. Like peptides, protein hydrolysates from collagen, a dominant protein of such materials, play an important role. Peptide bioactivities include antioxidant, antihypertensive, antidiabetic, antimicrobial, anti-inflammatory, anticoagulant, and anti-cancer effects as well as immunoregulatory and wound-healing activities. These peptides exert their effects through mechanisms such as enzyme inhibition, receptor modulation, and free radical scavenging, among others. Fish, algae, mollusks, crustaceans, microbes, invertebrates, and marine by-products such as skin, bones, and viscera are some of the key marine sources of bioactive proteins and peptides. The advancements in the extraction and purification processes, e.g., enzymatic hydrolysis, ultrafiltration, ion-exchange chromatography, high-performance liquid chromatography (HPLC), and molecular docking, facilitate easy identification and purification of such bioactive peptides in greater purity and activity. Despite their colossal potential, their production, scale-up, stability, and bioavailability are yet to be enhanced for industrial applications. Additional work needs to be carried out for optimal extraction processes, to unravel the mechanisms of action, and to discover novel marine sources. This review emphasizes the enormous scope of marine-derived peptides and proteins in the pharmaceutical, nutraceutical, cosmeceutical, and functional food industries, emphasizing their role in health promotion and risk reduction of chronic diseases.