Anti-trypanosomal Activity of Picrorrhiza kurroa rhizomes against Trypanosoma evansi

Abstract

In our quest for more effective and efficient means of obtaining trypanocidal extracts/compounds from medicinal plants, for leads in developing new trypanocide against trypanosomes, Picrorrhiza. kurroa rhizomes were extracted with  solvent, methanol, at different concentrations  ((250-1000 µg ml-1) and tested against Trypanosoma evansi on Alsever’s medium. Trypanosomes were suspended in Alsever’s solution with inactivated bovine serum at 58oC for 1 h at appropriate conditions for antitrypanosomal activity.  Trypanosomes concentration was 1x10⁶ parasites/ml.  In vitro cytotoxicity test of methanolic plant extract (MPE) of P.  kurroa at concentrations (1.56-100 µg ml-1) was done on Vero cells grown in Dulbecco's Modified Eagle Medium (DMEM) . At 250 µg ml-1 of MPE of P.  kurroa, there was significant ant- trypanosomal activity with  drastic reduction of trypanosomes count (40.00±0.0   to  4.667±0.67 )  was observed  after 5 h of incubation. But at 500 µg ml-1 of MPE of P.  kurroa, trypanosomes were completely killed in corresponding ELISA plate wells (40.00±0.0   to 0.0±0.0)  after 5 h of incubation, which was statistically equivalent to diminazine aceturate (50µg/ml) standard drug at 4 h. Both MPE of P. kurroa rhizomes and diminazine aceturate were cytotoxic to Vero cells in all concentrations except at 1.56-6. 25 µg ml-1.  MPE of P.  kurroa demonstrated  marked anti-trypanosomal activity with significant difference ((P ≤ 0.05 to 0. 01).). MPE of P. kurroa rhizomes and diminazine aceturate had the same level of in vitro cytotoxic effects on Vero cells. In this current report, Alsever’s medium supported trypanosomes with observed anti-trypanosomal activity. The outcome of this research could be further strengthened by (e.g. bioassay-guided purification) of P. kurroa for isolation of trypanocidal compound(s) that may lead to development of new trypanocide.