In vitro antibacterial and antioxidant activities of brown seaweeds

Marine environment is an excellent source of reservoir for biologically active natural products, and exhibits structural features that have not been found in terrestrial natural products. Hence, we made an attempt to study antibacterial and antioxidant activities of methanolic-brown seaweed extracts of Stoechospermum marginatum (SMME) and Sargassum wightii (SWME). The phytochemical analysis of SMME and SWME has confirmed the presence of various fixed oil, tannin, flavonoids, phenol compounds, saponin etc. The SWME showed maximum activity against S. aureus and minimum activity against E. coli. The SWME has showed the highest radical scavenging property in all the tested assay. The bioactive metabolites of the extracts were chemically characterized by FTIR and GCMS analyses. GC-MS analysis of SWME revealed the presence of a major chemical compound, hexadecanoic acid, methyl ester (13.35%) which might be the responsible for the recorded activity. The FTIR spectrum analyses of crude extracts revealed the presence of alkyl halides, alkanes, amides, aromatics and carboxylic acids. Hence, the present study could form a base line for the biomedical utilization of the seaweed S. wightii.