Antiplasmodial activity of medicinal plants from Chhotanagpur plateau, Jharkhand, India.
Background: The alarmingly increasing problem of drug resistance in treatment of malaria has led to an urgent need for identifying new anti-malarial drugs for both prophylaxis and chemotherapy. Aim of the study The present study presents a systematic exploration of the ex vivo blood stage antiplasmodial potential of medicinal plants to corroborate their traditional usage against malaria in Jharkhand, India. Methods: An ethnobotanical survey in and around Ranchi was done to grasp the traditional knowledge of medicinal plants used by local healers for malaria, other fevers and for other medicinal purposes like, antiamoebic, antihelmenthic, antidote to poisons, etc. Following the survey, the selected 22 plant samples were extracted in ethanol for studying ex vivo SYBR Green I fluorescence assay based anti-plasmodial activity against both chloroquine-sensitive Pf3D7 and chloroquine resistant PfINDO strains of Plasmodium falciparum grown in human red blood cell cultures. Cytotoxicity was determined against HeLa and L929 cells using MTT assay. Further the most potent extract was chromatographed on reverse phase HPLC towards antiplasmodial activity guided purification of metabolites. Results: Of the 22 plant species assayed, the highest antiplasmodial activity (Pf3D7IC50≤5 µg/ml) was seen in leaf ethanol extracts of Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson, Calotropis procera (Aiton) Dryand. and Annona squamosa L. and bark ethanol extract of Holarrhena pubescens Wall. ex G.Don. Leaf ethanol extract of H. pubescens, bark ethanol extract of Pongamia pinnata (L.) Pierre and whole plant ethanol extract of Partheniumhysterophorus L. showed promising activity (IC50 6-10 µg/ml). Good antiplasmodial activity (IC50: 11-20 µg/ml) was observed in leaf ethanol extract of Bryophyllum pinnatum (Lam.) Oken and whole plant ethanol extract of Catharanthus roseus (L.) G.Don. The extracts of plants showing highest to good antiplasmodial activity exhibited HeLa/Pf3D7 selectivity indices of the order of 20-45. Bioassay guided fractionation of P. hysterophorus led to fivefold enrichment of antiplasmodial activities (IC50 ∼450 ng/ml) in some fractions. Conclusion: These results provide confirmation to the traditional usage of some medicinal plants against malaria in areas around Ranchi, Jharkhand.