Harnessing the Antioxidant, Antibacterial, Anticoagulant, and Anticancer Activities of Padina pavonica with High Safety Profile for Drug Development

Abstract: The brown macroalga Padina pavonica has gained attention for its bioactive compounds with potential health benefits. This study investigates the chemical composition, antioxidant, antimicrobial, anticoagulant, and anticancer properties of P. pavonica ethanolic extract. Quantitative analysis revealed high levels of phenolics (31.79 ± 2.59 mg GAE/g), phlorotannins (2.57 ± 0.16 mg PGE/g), carotenoids (38.95 ± 2.30 μg βCE/g), and proteins (4.60 ± 0.17 mg BSAE100/g). The extract demonstrated interesting antioxidant activity (DPPH-IC50 = 213.25 ± 14.25 μg/mL) and antimicrobial activity toward Escherichia coli, Staphylococcus aureus, and a methicillin-resistant Staphylococcus aureus (MRSA) (MICs of 182.16 ± 48.89, 234 ± 78.12 and 182.16 ± 48.89 μg/mL, respectively). Anticoagulant activity was observed with prolonged APTT and PT values, suggesting inhibition of coagulation pathways. Cytotoxicity assays demonstrated significant anticancer activity against U2OS osteosarcoma cells, showing IC50 values of 41.8 ± 5.6 μg/mL (24 h) and 13.0 ± 1.7 μg/mL (48 h), with minimal toxicity to non-tumorigenic HaCaT cells and erythrocytes at concentrations below 5000 µg/mL. These findings highlight P. pavonica as a promising supply of biologically active compounds with potential applications in nutraceuticals, pharmaceuticals, and functional foods.