IN VITRO ANTITRYPANOSOMAL EVALUATION OF PICRORHIZA KURROA RHIZOMES

Abstract

In this study, Picrorrhiza kurroa rihzomes were cold extracted with methanolic solvent at concentrations (250-1000 $\mu$g ml-1). The methanolic plant extract (MPE) obtained was tested against Trypanosoma evansi for antitrypanosomal activity. This was carried out on Vero cells grown in Dulbecco's Modified Eagle Medium (DMEM) and supplemented with foetal calf serum (FCS) 20-40% at appropriate conditions. In vitro cytotoxicity test of P. kurroa rhizomes extract at concentrations (1.56-100 $\mu$g ml-1) was done on Vero cells but without FCS. In vivo infectivity test was done in mice. Results of in vitro antitrypanosomal activity varied from immobilization, reduction and to the killing of trypanosomes in corresponding ELISA plate wells. At 750 $\mu$g ml-1of MPE, there was marked reduction of average mean trypanosomes count in the corresponding ELISA plate wells as observed (39.00±0.0to 19.00±0.0). But at 1000$\mu$g ml-1 of the test extract of P. kurroa, there was complete killing of trypanosomes at 8 h of incubation, which was comparable to diminazine aceturate (50 $\mu$g ml-1) at 4

h. Trypanosomes counts decreased in concentration and time –dependent manner with significant difference (P<0.05). MPE of P. kurroa and diminazine aceturate, standard drug, were cytotoxic to Vero cells except at concentrations of 1.56-6. 25 $\mu$g ml-1. Both MPE and diminazine aceturate had the same cytotoxic levels. Group of mice inoculated with contents of ELISA plate wells with apparently killed trypanosomes survived for more than 30 days. While, the other group of mice inoculated with contents of ELISA plate wells with reduced trypanosomes died of parasitaemia. Moderate antitrypanosmal activity of MPE of P. kurroa was observed