In vitro antiplasmodial activity of Clathria vulpina sponge associated bacteria against Plasmodium falciparum

ObjectiveTo identify the possible antiplasmodial drugs from bacteria associated with marine sponge Clathria vulpina (C. vulpina).MethodsThe C. vulpina samples were collected from Thondi coast and subjected to enumeration and isolation of associated bacteria. Filtered and sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μg/mL) from isolated bacterial strains were screened for antiplasmodial activity against Plasmodium falciparum. Potential extracts were also screened for biochemical constituents.ResultsThirty one bacterial strains were isolated from twelve sponge samples collected from Thondi coast and screened for antiplasmodial assay. The count of bacterial strains were maximum in November 2007 (19×10⁴ CFU/g) and the average count was maximum during the monsoon season (110×10³ CFU/g). The antiplasmodial activity of strain THB15 was highly comparable (IC₅₀ = 20.73 μg/mL) with the positive control chloroquine (IC₅₀ = 19.59 μg/mL) and 21 bacterial strains showed IC₅₀ value of more than 100 μg/mL. Statistical analysis reveals that, significant in vitro antiplasmodial activity (P<0.05) was observed between the concentrations and time of exposure. The chemical injury to erythrocytes showed no morphological changes in erythrocytes by the ethyl acetate extract of bacterial strains after 48 h of incubation. The in vitro antiplasmodial activity might be due to the presence of sugars and alkaloids in the ethyl acetate extracts of bacterial strains.ConclusionThe ethyl acetate extract of THB15 possesses lead compounds for the development of antiplasmodial drugs.