ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF EXTRACTS FROM SELECTED ALGAL SPECIES

Antioxidant and antimicrobial potential of oil extracts of four different algal species were evaluated. Microwave assisted extraction method was used for oil extraction and DPPH scavenging assay was used to determine the antioxidant activity. Higher antioxidant activities were observed in methanolic extract in the order Oedogonium sp. > Stigeoclonium sp. > Ulothrix sp. > Nitzschia sp. The IC50 values of Oedogonium sp., Stigeoclonium sp. and Ulothrix sp. were 19.47, 20.88 and 22.92 mu g/ml, respectively. However for the Nitzschia sp. it was observed that ethanolic extracts had higher antioxidant potential as compared to methanolic extract. Antibacterial activity of all the ethanolic extracts was more against Gram-negative bacteria as compared to methanolic extracts on the concentrations used in the present study. Of the all species tested for antimicrobial activities, the maximum zone of inhibition was shown by ethanolic extract of Ulothrix sp. against Staphylococcus aureus at the concentration of 50 mu g/ml.