EXTRACTION AND CHARACTERIZATION OF ANTIMICROBIAL ACTIVE SUBSTANCE FROM CYANOBACTERIA NOSTOC CARNEUM AND ANABAENA CIRCINALIS

摘要

Cyanobacteria are rich sources of biologically active compounds have recently found enormous application in human and animal medicine. In this study, the organic extracts of cyanobacteria Nostoc carneum and Anabaena circinalis exhibited antagonistic activity against some pathogenic Grampositive bacteria (Staphylococcus aureus, Staphylococcus aureus (MRSA), Enterococcus faecalis and Streptococcus pyogenes), Gram-negative bacteria (Pseudomonas aemginosa and Shigella flexneri) and fungi (Candida glabrata, Candida tropicalis, Candida albicans and Fusarium oxysporum). The results indicated that the highest antimicrobial activity obtained from ethanol and ethyl acetate extracts of N. carneum against Pseudomonas aeruginosa and Fusarium oxysporium, respectively, and methanol extracts of A. variabilis against Enterococcus faecalis and Candida tropicalis. The antagonistic material for ethanol extract of N. carneum was characterized by GC-MS which identified the presence of main compounds as hexadecanoic acid, Phytol, acetate, Octadecadienoic acid and Octade- catrienoic acid, etc. FTIR spectra of algal extracts which indicated the presence of aliphatic compounds and have different active groups (OH, NH, CH_2, NO and C=O). Finally, the results of this study proved that the tested cyanobacteria might be a good source for the production of promising antimicrobial agents and therefore it can be used as an alternative nature antibiotic against synthetic conventional antibiotics.