Trypanocidal efficacy of three medicinal plants (Erythrina abyssinica,Tinospora bakis and Polygala erioptera) againstTrypanosoma evansiin rats

Abstract

This study was designed to test the trypanocidal efficacy of three medicinal plants (Erythrina abyssinica, Tinospora bakis and Polygala erioptera) againstTrypanosoma evansiin experimentally infected rats. Two hundred and ninety outbred albino rats were used. The animals were divided into twenty nine groups; each group consisted of ten rats. All rats were inoculated with parasites mounting to 3 – 4 parasites per field intraperitoneally except the negative control group. The plants extracts (water, methanolic and chloroformic) were injected intraperitoneally for treated groups after appearance of parasitaemia. All infected untreated rats died bythe end of the second week after infection, with decrease in RBCs counts, Hb concentration, PCV, and increase in Bil, ALT and AST activity. In rats treated with water extract ofErythrina abyssinicathe parasitaemia disappeared for short period and reappeared again. Rats receiving 100 mg and 50 mg of either methanolic or chloroformic total extracts were cured of infection but the doses appeared to be toxic. The 10 mg total extract dose was more effective in clearing infection. In rats treated with water extract ofTinospora bakisparasitaemia disappeared temporarily and relapse occurred. The 100 mg dose of the methanolic extract cured the infection but was toxic. The 10 mg dose could clear the infection without relapse. Noantitrypanosomal effect was observed with chloroformic extract of Tinospora bakis. Polygala erioptera extracts gave the best results. The 100 mg of water extract was successful in eliminating infection, but the 50 mg and 10 mg water extract could not eliminate the parasite. The 100 mg and 50 mg of either methanolic or chloroformic extracts cleared the parasite but were 17 toxic. The 10 mg of either extracts eliminated the infection and all animals survived throughout the experiment period. In all treated groups there was variable decrease in haematological parameters and increase in serum enzymes. Further studies are recommended using Polygala erioptera extracts as antitrypanosomal treatment.