Ecology, Environment and Conservation Paper

IN VITRO ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES OF CYANOBACTERIA ISOLATED FROM COCHIN ESTUARY, INDIA

S. Lekshmi and A.V. Saramma

Abstract

The antibacterial and antioxidant activities of two cyanobacteria, Gloeocapsa sp. Kützing and Synechocystis aquatilis Sauvageau isolated from Cochin estuary were analyzed. Antibacterial activity was tested against ten bacterial pathogens. The diethyl ether extract of Gloeocapsa sp. could effectively inhibit four tested bacteria (Escherichia coli, Bacillus sp., Vibrio harveyi, Vibrio mimicus). Staphylococcus aureus was sensitive to the ethanol extract of S. aquatilis. The aqueous extract of both strains were ineffective. The antioxidant activity of S. aquatilis was higher than Gloeocapsa sp. S. aquatilis had 12.53±0.207 µg GAE/mg phenolic content, 60.9±1.49 µg AE/mg antioxidant activity and 46.78% 2, 2 diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Gloeocapsa sp. showed 11.22±0.067 µg GAE/mg phenolic content, 26.93±0.057 µg AE/mg antioxidant activity and 37.22% DPPH radical scavenging activity. The ferric reducing antioxidant power assay and DPPH radical scavenging activity were dose dependent. The methanol and dimethyl sulphoxide extracts of the strains showed maximum activity. The study indicates that these strains could be exploited as source of antibacterial and antioxidant compounds.