In vitro and In vivo Antitrypanosomal Effects of Mitracarpus villosus Leaves

Abstract

The in vitro antitrypanosomal activity of the aqueous, ethanolic, methanolic and chloroform extracts of the leaves of Mitracarpus villosus  was evaluated on Trypanosoma b. brucei by means of a blood incubation infectivity test (BIIT) using Diminal® (diminazene aceturate) as  positive reference.. The aqueous extract was fractionated to yield eight fractions by means of a column chromatography, each of the  eight fractions were tested in vitro by means of BIIT. The therapeutic potentials of fractions II, III, IV and the crude aqueous extract were  investigated in mice infected with T. brucei; the animals were treated orally at doses of 100 and 200 mg/kg body weight daily until their  death. Phytochemical screening of the aqueous extract showed the presence of flavonoids, tannins, alkaloids, anthraquinones, saponins,  and glycosides. Fractions II, III and IV emerged as the only fractions with appreciable trypanocidal activity. Although, all the fractions and  the crude aqueous extract showed some degree of activity at both doses, fraction IV conferred the best antitrypanosomal effect as it extended the life span of the animals by 4 days, when compared to the negative control, and its ability to decrease the parasites 8 days  post treatment. Gas chromatography-mass spectrometry of fraction IV, revealed 13 peaks, two of which were 9, 10-Anthracenedione-α  anthraquinone and (4-Phenyl-tetrahydro-pyran-4-ny)-piperidin-1-yl-methanone, derivatives of anthraquinones and alkaloids. The result  revealed that the aqueous extract and fraction IV possessed trypanocidal activity which may be attributed to the presence of the  anthraquinone and alkaloidal derivatives.