Beneath the waves: Unveiling the potent cytotoxic power of S. marginatum

• Seaweed is recognized for its rich source of novel and promising lead biomolecules, particularly in brown seaweeds. • Secondary metabolites from seaweed have gained prominence over conventional synthetic active ingredients in drug discovery and pharmacotherapeutics. • Seaweed polysaccharides exhibit diverse biological activities, including anticancer, antioxidant, antiviral, antidiabetic, and antibacterial effects. • Polysaccharides from seaweeds like alginic acid, fucoidans, laminarians, and carrageenans are widely used in formulating pharmaceutical dosage forms. • Ethanolic extracts of S. marginatum exhibit cytotoxic activity, with promising results against cancer cell lines, including choriocarcinoma. • S. marginatum emerges as a promising source of biomedical secondary metabolites for future research, particularly in developing novel therapies for oral squamous cell carcinoma.