<i>In vitro</i> anti-trypanosomal activity of <i>Bitis arietans</i> crude venom against <i>Trypanosoma brucei brucei</i>

Abstract

African Animal trypanosomosis (AAT) otherwise known as Nagana is a resurgent disease in Africa. It is caused by Trypanosoma brucei brucei, Trypanosoma congolense, Trypanosoma vivax, Trypanosoma evansi among others. It is transmitted cyclically by tsetse flies (Diptera: Glossinidae) or mechanichally by other biting flies. In the absence of efficient vaccines, chemotherapy, together with vector control, remains the most important measure to control the disease. The parasites have developed resistance against the disease due to improper exposure to chemotherapeutic agents. These present challenges necessitate the development of alternative therapeutic agents against the disease. Therefore, the aim of this study was to test for the in vitro anti-trypanosomal activity of Bitis arietans (Puff adder) venom against Trypanosoma brucei brucei species. Protein profiles of the crude snake venoms were determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS- PAGE), and the results revealed the venoms contain 10 different proteins. The IC₅₀ of the venom was also determined by 3(4,5-dimethylthiozol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay and was found to be 0.3085μg/ml. The in vitro anti-trypanosomal activity of the graded dose of the venom was evaluated over a period of 5 hours in comparison with two standard drugs; Diminaveto and Babezene (12mg/15ml) as positive control and phosphate buffered saline glucose (PBSG) pH 7.4 as negative controls. The venom lysed the parasites across all the different concentration within 30 minutes of incubation. It was also found to have mild or no lytic effects on the erythrocytes for the period of the incubation. The results show that Bitis arietans has anti-trypanosomal activity and can be a potential drug target against the disease.

Keywords: Bitis arietans venom, anti-trypanosomal activity, in vitro, Trypanosoma brucei brucei