Planta Med 2007; 73 - P_200
DOI: 10.1055/s-2007-986981

In vitro trypanocidal activity of methanolic extract of Picrorrhiza kurroa rhizomes against Trypanosoma evansi

P Shaba 1, NN Pandey 1, OP Sharma 2, JR Rao 3, RK Singh 4
  • 1Division of Medicine, Indian Veterinary Research Institute, Izatnagar -243122, India
  • 2Regional Station, Indian Veterinary Research Institute, Palampur 176061
  • 3Division of Parasitology, Indian Veterinary Research Institute, Izatnagar -243122, India
  • 4Regional Station, Indian Veterinary Research Institute, Palampur 176061, India

In the course of screening of medicinal plants for possible antitrypanosomal drug against important flagellate blood protozoan parasite of the genus Trypanosoma, Picrorrhiza kurroa rhizomes were screened for their antitrypanosomal activity and cytotoxicity. Reports of the resistance to currently used trypanocides are on the increase in different parts of the world. No new drug has been introduced in the market for more than half a century and prospect for a vaccine remains elusive due to high genetic variability of trypanosomes. Vero cell line maintained in Dubecco's Modified Eagle Medium (DMEM) in ELISA plates was incubated with Trypanosoma evansi for more than 12h. Methanolic plant extract (MPE) of Picrorrhiza kurroa was solubilized in 1% dimethylsulphoxide. MPE was added to the Vero cell culture medium at different concentrations (250–1000µg/ml) and incubated at appropriate conditions. Cytotoxicity test of MPE was carried out on Vero cell line at different concentrations (1.56–100µg/ml) dissolved in the same medium and incubated at same conditions for 72h. For acute toxicity testing MPE at concentration of 2000mg/kg body weight was administered to mice which were observed for more than two weeks. In vitro, Picrorrhiza kurroa induced immobilization and killing of the parasites in concentration-time dependent manner. At 250µg/ml of the test MPE, concentration of trypanosomes was reduced from 40.00±.00 to 4.667±0.67. But at 500µg/ml, trypanosomes were completely killed at 4h of incubation which was same as diminazine aceturate (50µg/ml), standard reference drug with significant difference (P ≤0.01).

Both immobilized (clumped trypanosomes) and apparently killed trypanosomes were injected into two groups of mice which were observed for a period of 30 days. Mice injected with immobilized trypanosomes developed parasitemia while, the other group did not. MPE of Picrorrhiza kurroa and diminazine aceturate appeared to be toxic to mammalian cell line at same concentration (6.25µg/ml). No mortality was recorded during acute toxicity test