In Vitro Assessment of Antimicrobial Activities of Ether and Hexane Extracts of microalgae Chlorella vulgaris against Aeromonas hydrophila and Micrococcus luteus bacteria

Increase in emergence of drug-resistant strains of microorganisms have necessitated finding natural compounds with antimicrobial properties and negligible side effects. Microalgae rich in active metabolites could be used in this branch of pharmaceutical industries. Chlorella vulgaris a microalgae was collected from the International Sturgeon Institute- Rasht- Iran. Antibacterial activities of hexane and ether extracts of C. vulgaris against gram-positive Micrococcus luteus and Gram-negative Aeromonas hydrophila bacteria were evaluated. When the required volume and cell concentration of algae under pure culture condition reached the hexane and ether extracts of the cells were obtained according to Cannell et al. (1988) antibacteria activities were examined using well diffusion methods (1). Hxane and ether extracts of C. vulgaris inhibited A. hydrophila and M. luteus bacteria. The diameter of inhibition zone of hexane extract against M. luteus and A. hydrophila, varied between 9.3-11.6 and 9.6- 11 mm while these diameters for ether extract varied between range 20.3-25 and 7.6-16 mm respectively. Gas chromatography mass spectrophotometry was used to identify different substances in diethyl ether and hexane extracts. The main substances in ether extract were ketone compounds, esters, hydrocarbons, siloxane, Saylyl, terpenes and Hydrvsaylyl polyesters. In hexane extract the main substances were hydrocarbons, siloxane, Saylyl and Hydrvsaylyl are polyester. The inhibitory effect of ether extract was higher than the hexane extract thus it could be used as a solvent for extraction of antimicrobial compounds.