Antibacterial and free radical scavenging potential of some cyanobacterial strains and their growth characteristics

Shazia Suhail, Deboshree Biswa

Abstract

The present study deals with the growth characteristics of several cyanobacterial strains (Anabaena variabilis, Oscillatoria sp., Chroococcus sp. Nostoc sp., Plectonema boryanum and Scytonema sp.), evaluation of their antibacterial activity and free radical scavenging ability. The maximum specific growth rate was noticed in Nostoc sp. and Scytonema sp. followed by Plectonema boryanum, Chroococcus sp. and Oscillatoria sp. whereas, Anabaena variabilis exhibited minimum growth rate. Antibacterial activity of hexane and methanol extracts of cyanobacteria was assayed by disc diffusion method against Staphylococcus epidermidis bacterium. The tested bacterium responded differently to the types of extracts and cyanobacterial strains used. Hexane extracts exhibited more antibacterial potential as compared to methanol. Free radical scavenging activity by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) indicate the maximum antioxidant potential of P. boryanum followed by Scytonema sp. whereas, Nostoc sp. showed least activity. Though this kind of investigation creates quite a general view of cyanobacterial possibility to produce biologically active compounds still it points out the necessity of exploring cyanobacterial strains as potentially excellent sources of these substances and reveals the most prospective strains for further investigations