In vitro antiplasmodial activity of marine sponge Stylissa carteri associated bacteria against Plasmodium falciparum

Objective: To identify the possible antiplasmodial drugs from bacteria associated with marine\udsponge Stylissa carteri (S. carteri). Methods: The S. carteri samples were collected from Thondi\udcoast and subjected for enumeration and isolation of associated bacteria. Filter sterilized\udextracts (100, 50, 25, 12.5, 6.25 and 3.125 毺 g/mL) from isolated bacterial isolates were screened for\udantiplasmodial activity against Plasmodium falciparum (P. falciparum) and potential extracts were\udalso screened for biochemical constituents. Results: Twelve samples of S. carteri were collected\udand subjected for enumeration and isolation of associated bacteria. The count of bacterial isolates\udwere maximum in November 2007 (34暳 104 CFU/g) and the average count was maximum during\udthe monsoon season (203暳 103 CFU/g). Thirty two morphologically different bacterial isolates were\udisolated from S. carteri and the ethyl acetate bacterial extracts were screened for antiplasmodial\udactivity against P. falciparum. The antiplasmodial activity of a isolate THB17 (IC 50 20.56 毺 g/\udmL) extract is highly comparable with the positive control chloroquine (IC50 19.59 毺 g/mL) and 13\udbacterial extracts which showed IC\ud50 value of more than 100 毺 g/mL. Statistical analysis reveals\udthat, significant in vitro antiplasmodial activity (P<0.05) was observed between the concentrations\udand time of exposure. The chemical injury to erythrocytes showed no morphological changes in\uderythrocytes by the ethyl acetate extract of bacterial isolates after 48 h of incubation. The in vitro\udantiplasmodial activity might be due to the presence of reducing sugars and alkaloids in the ethyl\udacetate extracts of bacterial isolates. Conclusions: The ethyl acetate extract of THB17 possesses\udlead compounds for the development of antiplasmodial drugs