In vitro Anti-trypanosomal Activity of Ethanolic and n-Hexane Extracts of Hymenocardia acida Stem Bark against Trypanosoma bruceibrucei and Trypanosoma congolense

Abstract

The development of resistance by trypanosomes to existing trypanocidal drugs necessitates the need to search for safer and more effective alternative drugs with a broad spectrum of activity. Hence, this study was carried out to evaluate the in vitro anti-trypanosomal activity of ethanolic and n-hexane extracts of Hymenocardia acida stem bark against Trypanosoma congolense and Trypanosoma brucei brucei. The stem bark of H. acida was collected, identified, dried and then ground into fine powder. The powdered H. acida stem bark was extracted successively using n-hexane and ethanol to obtain n-hexane and ethanolic extracts, respectively. Phytochemical screening of the extracts was carried out using standard procedure. In vitro, anti-trypanosomal activity of different concentrations of the stem bark extracts (2.5 mg/mL to 40.0 mg/mL) were determined using motility assay with diminazene aceturate (100 µg/mL) and phosphate buffered saline used as positive and negative controls, respectively. Results of the phytochemical screening revealed that flavonoids, alkaloids, saponins, and tannins were present in the ethanolic and n-hexane extracts. In vitro, the anti-trypanosomal activity of ethanolic and n-hexane extracts was observed against T. brucei brucei and T. congolense. Cessation of trypanosome motility was observed after 30 and 50 minutes of exposure to 2.5 mg/mL of ethanolic extract and n-hexane extract, respectively, for both T. brucei brucei and T. congolense. In conclusion, ethanolic and n-hexane extracts of H. acida exhibited anti-trypanosomal activity against Trypanosoma brucei brucei and Trypanosoma congolense. Hence, the plant could serve as a source of new trypanocidal drugs.