Abstract:
Objective: To evaluate the antimalarial and antioxidant properties of stem bark extracts
of Haematostaphis barteri (H. barteri).
Methods: The prophylactic activity of the plant was performed by dosing mice with
sulfadoxine-pyrimethamine (1.2 mg/kg), aqueous extract (30, 100, 300 mg/kg) and
dichloromethane/methanol (D/M) (30, 100, 300 mg/kg) extracts of H. barteri for 3 days. On
the 4th day, the mice were inoculated with Plasmodium berghei. The parasite density was
estimated for each mouse 72 h post-parasite inoculation. The curative activity of the plant
was also performed by inoculating mice with Plasmodium berghei. Three days later, they
were treated with artemether-lumefantrine (4 mg/kg), aqueous and D/M extracts of H. barteri
stem bark for 5 days. The in vitro antioxidant property of the aqueous extract was determined
by using the reducing power, nitric oxide and total antioxidant capacity assays.
Results: The aqueous extract exerted significant (P < 0.05) curative and prophylactic
antimalarial activities. The D/M extract exhibited significant curative (P < 0.05) but not
prophylactic antiplasmodial effect. The aqueous extract exhibited in vitro antioxidant
property with IC50's of (0.930 ± 0.021) mg/mL, (0.800 ± 0.001) mg/mL and (0.22 ± 0.05)
mg/mL in the total antioxidant capacity, reducing power and nitric oxide assays. Histo-
logical assessment of the liver of aqueous and D/M treated animals did not reveal any
sign of toxicity.
Conclusions: H. barteri is not toxic which exerted significant curative antiplasmodial
effects but the prophylactic property was however fraction dependent. The mechanism of
the antiplasmodial activity of H. barteri may partly be mediated by its antioxidant
property.
