Antibacterial activity of selected marine macro algae against vancomycin resistant Enterococcus faecalis

Objective:To evaluate the antibacterial activity of different extracts of Caulerpa chemnitzia(Epser)J.V.Lamououx,Caulerpa racemosa(Frosk.)Weber-van-Bosse(C.racemosa),Caulerpa scalpelliformis(R.Br.)Weber-van-Bosse,Ulva lactuca Lin,Ulva fasciata Dellie,Ulva reticulata Forsk,Stoechospermum marginatum(Ag.)Kutz(S.marginatum),Sargassum wightii Grev,Gracilaria verrucosa(Huds.)Papenfuss and Gracilaria edulis(S.G.Gemelin)P.C.Silva against Enterococcus faecalis(MTCC 439)(E.faecalis)and one clinical isolate of vancomycin resistant E.faecalis.Methods:The selected marine macro algae were extracted with different solvents viz.,hexane,chloroform,ethyl acetate,acetone and methanol.Antibacterial assay was carried out by using disc diffusion method,determination of minimum inhibitory concentration and minimum bactericidal concentration.Results:The maximum antibacterial activity was recorded in the ethyl acetate extracts of S.marginatum and C.racemosa than the other extracts.The mean zone of inhibition produced by the extracts in agar diffusion assays against the tested bacterial strains ranged from 7.1 to 14.5 mm.The minimum inhibitory concentration was between 250 and 500μg/mL,while the minimum bactericidal concentration was from 500 to 1000μg/mL.The ethyl acetate extracts of the seaweeds showed the presence of strong terpenoids,tannins and phenolic compounds compared with the other solvent extracts.Conclusions:These findings suggest that ethyl acetate extracts of S.marginatum and C.racemosa can be used as an antibacterial substance for the treatment of infection caused by E.faecalis.