Bioactivity of selected seaweeds from gulf of Mannar, South-east cost of India

Abstract

Objective: To evaluate antimicrobial and antimycobacterial activity of three seaweeds [Gelidiella acerosa (G. acerosa), Turbinaria conoides (T. conoides) and Sargassum wightii (S. wightii)] from Gulf of Manner. Methods: Three seaweeds G. acerosa, T. conoides and S. wightii were collected from Gulf of Mannar, South-East Coast of India. Solvent extraction of the selected seaweeds was done using hexane and ethanol. These extracts were tested for antibacterial activity against four bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus) by disc diffusion method. The active extracts of T. conoides were tested for antimycobacterial activity by luciferase reporter phage assay at two different concentrations (100 µg/mL and 500 µg/mL). Results: Among the tested seaweeds, ethanol extract of T. conoides showed maximum antibacterial activity against Bacillus subtilis and Staphylococcus aureus followed by hexane extract at concentration of 1 mg/disc. The remaining two seaweeds (G. acerosa and S. wightii) did not show any activity. The ethanol extract of T. conoides exhibited maximum antimycobacterial activity (87.33%) followed by hexane extract (74.68%) against Mycobacterium tuberculosis H37Rv at 500 µg/mL. Conclusions: Ethanol extract of T. conoids showed both antibacterial and antimycobacterial activity. Further photochemical studies are needed to identify the active antimycobacterial agents.