Abstract:
Background: African Trypanosomiasis is a neglected tropical disease with a large impact on the livelihood of
the rural poor in Sub-Saharan Africa. The available drugs for managing this disease are old, expensive and are
facing the problem of drug resistance. Thus, the aim of this study was to evaluate in vivo antitrypanosomal
efficacy of aqueous and absolute methanol leaf extracts of Verbascum sinaiticum Benth. against Trypanosoma
congolense field isolate.
Methods: Verbascum sinaiticum (Local name ‘qetetina’) is a biennial plant, and 60–150 cm tall. It is traditionally
used to treat wound, stomachache, viral infection, cancer, sunstroke, fever, abdominal colic, diarrhea,
hemorrhage, anthrax, and hepatitis. The efficacy of aqueous and absolute methanol leaf extracts of V. sinaiticum
was evaluated in a randomized experiment with Swiss albino mice infected with T. congolense field isolate. The
extracts were administered at doses of 100, 200 and 400 mg/kg by intraperitoneal injection for seven days at 12
Days Post-Infection (DPI) when the peak parasitaemia level was approximately 108 trypanosomes/ml.
Parasitaemia, Packed Cell Volume (PCV), mean survival time and change in body weight were used as indices for
monitoring the efficacy of the extracts. Diminazene (28 mg/kg) was used as a positive control while 2 % Tween
was used as the negative control. Phytochemicals screening were conducted following standard methods.
Results: The extracts showed no toxicity effect in Swiss albino mice and had LD50 above 2000 mg/kg. The
phytochemicals screened in V. sinaiticum were alkaloids, flavonoids, glycoside, saponins, steroids, phenolic
compounds, and tannins. The mice treated with absolute methanol leaf extract of V. sinaiticum at 400 mg/kg
dose had significantly lower mean parasitaemia (7.20 ± 0.16) (p < 0.001) as compared to the negative control
group (8.82 ± 0.12) on day 14 of treatment. Animals treated with the same dose had significant (p < 0.001) higher
PCV value and body weight and as well as the highest mean survival time of 40.20 ± 0.31 days as compared to
the negative control at the end of the observation period.
Conclusion: This study established that Verbascum sinaiticum had trypanocidal activity. The crude extracts have
partially eliminated trypanosomes in a dose-dependent manner. The study can be a basis for future in-depth
analysis of the biologically active chemicals.
