Phytochemical Screening and In Vitro Antitrypanosomal Activity of Aqueous and Methanol Leaf Extract of Verbascum sinaiticum (Scrophulariaceae) against Trypanosoma congolense Field Isolate

Abstract

Background and Objectives: There is urgent need of search for alternative compounds for chemotherapy of African trypanosomiasis, a disease of major economic and public health importance. The current study investigated the phytochemical composition and in vitro antitrypanosomal activity of aqueous and methanolic leaf extracts of Clutia abyssinica (C. abyssinica) against Trypanosoma congolense (T. congolense) isolated from natural infection of cattle. Materials and Methods: The aqueous and methanol extracts were screened for various secondary metabolites using standard methods. The in vitro antitrypanosomal assay was carried out by monitoring the extract concentrations of 4, 2, 1, 0.4 and 0.2 mg mL-1 for cessation or reduction in motility of trypanosomes followed by inoculation of incubation mixtures to healthy mice and monitoring development of infection for 21 days. Results: Phytochemical screening revealed presence of alkaloids, anthraquinones, flavonoids, glycosides, phenolic compounds, saponins, steroids, terpenes and tannins. An appreciable in vitro activity was attained by the methanol extract of C. abyssinica at 4 mg mL-1 concentration which ceased motility of trypanosomes within 30 min and caused loss of infectivity of trypanosomes to mice which remained aparasitaemic for 21 days after the inoculation of the in vitro mixtures. Conclusion: The results obtained suggest ethno-pharmacological usefulness of the plant and necessitate further in vivo studies to be carried on isolated active substances from these plants.