DOI: 10.36347/sjams.2018.v06i09.060

Pages: 3545-3549

The aim of the study was to investigate the anti-pathogenic activities of selected cyanobacteria isolated from freshwater bodies of Sri Lanka. Ethanolic extract of six uni algal cultures i.e.,Oscillatoria sp., Synechococcus sp., Dermocarpa sp., Chroococcussp., Nostoc sp. and Microcystissp. were tested against five plant pathogens and seven human pathogens using agar disk diffusion method. Human pathogens include Escherichia coli ATCC 35218, E. coli ATCC 25922, Staphylococcus aureusATCC 25923, Pseudomonas aeruginosaATCC 27853, EntarococcusfaecalisATCC 29212, Klebsiellapneumoniaeand Candida albicans. Plant pathogens include Colletotricummusae, Colletotricumcoccodes, Pomopsissp., Tricodermasp., and Cladosporiumcladoplorioides. The cyanobacterial extract at the rate of 0.01 g/ml and 0.025 g/ml did not show any zone of inhibition on pathogenic fungi and bacteria. In the present study, at the rate of 0.05 g/ml extract concentration, Synechococcus sp. showed the zone of inhibition against highest 7 pathogens such as E. coli ATCC 35218, E. coli ATCC 25922, P. aeruginosaATCC 27853, K. pneumonae, E. faecalis ATCC 29212, C. musae, and C. coccodes. Cyanobacteria Oscillatoriasp. showed the zone of inhibition against six pathogens i.e., E. coli ATCC 35218, E coli ATCC 25922, S. aureusATCC25923, K. pneumonia, C. musaeand C. coccodes. However,Nostoc sp. showed zone of inhibition against 5 pathogens i.e., E. coli ATCC 35218, E. coli ATCC 25922, S. aureusATCC 25923, K. pneumonaeand E. faecalisATCC 29212. At the same time cyanobacteria Chrococcussp. and Microcystis sp. showed zone of inhibition against three pathogens each i.e.,E. coli ATCC 35218, E. coli ATCC 25922 and K. pneumonae. After increasing the cyanobacteria extract concentration to 0.1 g/ml, the zone of inhibition also increased. However, Dermocarpasp. did not show any inhibition at any concentration. The present study revealed that cyanobacterial extract can be an effective source in pharmaceutical use against human and pl