Critical review on bioactive substances from sea food and their health promoting effects

• Marine bioactive compounds show strong antimicrobial, anticancer effects etc. • Peptides from seafoods offer potent therapeutic benefits. • Polyketides and alkaloids of seafoods show strong anticancer potential. • Chitosan and omega-3s are key marine compounds with health benefits. • Marine biodiversity is vital for new drug discoveries. Seafood is a valuable source of bioactive compounds with significant therapeutic potential, contributing to human health through diverse biological activities. These compounds, derived from marine organisms such as fish, crustaceans, mollusks, and algae, exhibit antimicrobial, anti-inflammatory, anticancer, antioxidant, neuroprotective, and immunomodulatory properties. The structural diversity of seafood-derived bioactive compounds, shaped by the unique marine environment, often provides novel pharmacological applications. This review explores key classes of bioactive substances, including peptides, polysaccharides, lipids, alkaloids, polyketides, and terpenoids. Marine-derived peptides, such as antimicrobial peptides from crustaceans, have demonstrated broad-spectrum efficacy against bacterial and viral pathogens. Additionally, bioactive peptides exhibit antihypertensive effects by inhibiting angiotensin-converting enzyme (ACE), contributing to cardiovascular health. Polysaccharides such as chitosan, extracted from crustacean shells, and sulfated glycans, derived from marine algae and invertebrates, have shown significant anticancer activity by inducing apoptosis, modulating immune responses, and inhibiting tumor growth. Marine lipids, particularly omega-3 polyunsaturated fatty acids (PUFAs) like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play crucial roles in cardiovascular protection, cognitive function, and inflammation regulation. Furthermore, marine alkaloids, polyketides, and terpenoids exhibit potent anticancer, anti-inflammatory, and neuroprotective properties, with some compounds advancing into clinical trials. The increasing recognition of seafood-derived bioactive compounds highlights their potential in nutraceutical and pharmaceutical applications. However, sustainable harvesting practices, innovative extraction techniques, and further clinical studies are essential for fully unlocking their therapeutic benefits. This review emphasizes the importance of marine biodiversity in drug discovery and the need for continued research to develop functional foods and novel therapeutics addressing global health challenges.