Objective: To identify the possible antiplasmodial drugs from bacteria associated with marine sponge Clathria indica. Methods: Clathria indica samples were collected from Thondi coast and subjected for enumeration and isolation of associated bacteria. Filter sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μg.mL-1) from isolated bacterial isolates were screened for antiplasmodial activity against Palsmodium falciparum and potential extracts were also screened for biochemical constituents. Results: The count of bacterial strains were maximum in November 2007 (19×104 CFU.g-1) and the average count was maximum during the monsoon season (107×10 3 CFU.g-1). Thirty one morphologically different bacterial isolates were isolated from Clathria indica and the ethyl acetate bacterial extracts were screened for antiplasmodial activity against Palsmodiumfalciparum. The antiplasmodial activity of a isolate THB23 (IC 50 28.80 μg.mL-1) extract is highly comparable with the positive control chloroquine (IC50 19.59 μg.mL-1) and 17 bacterial extracts which showed IC50 value of more than 100 μg.mL-1. 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 carbohydrates and alkaloids in the ethyl acetate extracts of bacterial isolates. Conclusions: The ethyl acetate extracts of THB23 possesses novel compounds for the development of antiplasmodial drugs.

Objective: To identify the antiplasmodial drugs from the marine sponge Hyattella intestinalis (H. intestinalis) associated bacteria. Methods: The H. intestinalis samples were collected from Thondi coast and subjected for enumeration and isolation of associated bacteria. Filter sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125μg/mL) from bacterial isolates were screened for antiplasmodial activity against P. falciparum and potential extracts were also screened for biochemical constituents. Results: The count of THB isolates were maximum in November 2007 (20×10 4 CFU/g) and the average count was maximum during the monsoon season (77×103 CFU/g). A total of 29 bacteria were isolated based on the morphological characteristics and screened for antiplasmodial activity. The antiplasmodial activity of THB20 extract (IC50 41.88 μg/mL) showed at two fold concentration of IC50 value of the positive control chloroquine (IC50 19.59 μg/mL) and 14 bacterial isolates 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 THB isolates after 48 h of incubation. The antiplasmodial activity of potential bacterial isolates might be due to the presence of sugars and alkaloids in the ethyl acetate extracts. Conclusions: It is concluded from the present study that, the ethyl acetate extracts of THB20 posses novel metabolites for the development of newer antiplasmodial drugs.

Objective: To identify the possible antiplasmodial compounds from Achyranthes aspera (A. aspera), Acalypha indica (A. indica), Jatropha glandulifera (J. glandulifera) and Phyllanthusamarus (P. amarus). Methods: The A. aspera, A. indica, J. glandulifera and P. amarus were collected along Palk Strait and the extraction was carried out in ethanol. The filter sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μg/mL) of leaf, stem, root and flower extracts of A. aspera, A. indica, J. glandulifera and P. amarus were tested for antiplasmodial activity against Plasmodiumfalciparum. The potential extracts were also tested for their phytochemical constituents. Results:Of the selected plants species parts, the stem extract of A. indica showed excellent antiplasmodial activity (IC50= 43.81μg/mL) followed by stem extract of J. glandulifera (IC50= 49.14μg/mL). The stem extract of A. aspera, leaf and root extracts of A. indica, leaf, root and seed extracts of J.glandulifera and leaf and stem extracts of P. amarus showed IC 50 values between 50 and 100 μg/mL. Statistical analysis revealed that, significant antiplasmodial activity (P<0.01) was observed between the concentrations and time of exposure. The chemical injury to erythrocytes was also carried out and it showed that there were no morphological changes in erythrocytes by the ethanolic extract of all the tested plant extracts. The in vitro antiplasmodial activity might be due to the presence of alkaloids, glycosides, flavonoids, phenols, saponins, triterpenoids, proteins, and tannins in the ethanolic extracts of tested plants. Conclusions: The ethanolic stem extracts of P. amarus and J. glandulifera possess lead compounds for the development of antiplasmodial drugs.