GC-MS ANALYSIS, ANTIOXIDANT AND ANTIBACTERIAL ACTIVITY OF THE BROWN ALGAE, PADINA TETRASTROMATICA

Marine algae are one of the largest sources for biogenic compounds. They produce a wide variety of chemically active metabolites. They are found to possess significant antioxidant, and phytochemical activities. Macroalgae provides a great variety of metabolites and natural bioactive compounds with antimicrobial activity, such as polysaccharides, polyunsaturated fatty acids, phlorotannins and other phenolic compounds, and carotenoids. Several species of brown algae have been investigated for their bioactive natural products. The aim of the present study was to investigate the antioxidant, antibacterial activity and GC-MS analysis of active compounds present in the methanol extract of the brown algae, Padina tetrastromatica. For antioxidant activity, DPPH radical assay, ABTS radical cation scavenging assay, phosphomolybdenum reduction assay and Fe³⁺ reducing power assay were carried out. The maximum DPPH radical scavenging activity was 54.78%. The extract also exhibited significant antibacterial activity against the clinical pathogens, Vibrio cholera, Shigella flexneri and Pseudomonas aeruginosa. The phytochemical analysis showed the presence of alkaloids, terpenoids, steroids, flavonoids and phenolic compounds. GC-MS analysis revealed the presence of fatty acids and a flavone compound (2-Phenyl-4H-1-benzopyran-4-one), which is a potent antioxidant compound.