Antimicrobial activity of some marine algae of southwest coast of India

Acetone and ethanol extracts of five marine algae namely Caulerpa taxifolia, Chaetomorpha antennina, Cladophora fascicularis, Ulva lactuca and Gracilaria corticata collected from two locations in three seasons were tested for the growth inhibition of five bacteria and three fungi. Caulerpa taxifolia, Chaetomorpha antennina and Gracilaria corticata exhibited considerable inhibition against bacterium Bacillus subtilis and yeast Candida albicans. Distal parts of algae of summer season showed good inhibitory activity. None of the algal extracts inhibited bacterium Pseudomonas aeruginosa, fungi Aspergillus flavus and Fusarium oxysporum. A significant difference (p<0.01, ANOVA) in antibacterial activity of the extracts of Chaetomorpha antennina was found in different seasons. Significant difference (p<0.001, ANOVA) was also found in the inhibitory activities of acetone extracts of distal and proximal parts of Chaetomorpha antennina of summer. No relation was found between microbial growth inhibition and phenolic content of algae.