Evaluation of the antimalarial activity of the aqueous leaf extract of Gossypium barbadense (Malvaeceae) in mice

Some medicinal plants have been shown to have antimalarial activity when used as combination therapy. Gossypium barbadense has been used by herbal medicine practitioners in combination with other herbs, and as a monotherapy in the treatment of malarial infection. The study was, therefore, aimed at evaluating the antimalarial effect of the aqueous leaf extract of G. barbadense using mice infected with P. berghei. The suppressive effect was evaluated by administering 25 mice divided into five groups with 250, 500, and 1,000 mg/kg of aqueous leaf extract of G. barbadense, 5 mg/kg of chloroquine, and 10 mL/kg of distilled water, respectively, starting from the day of inoculation with P. berghei for four days. The curative effect was evaluated by administering 25 mice divided into five groups as above with treatment starting 72 h post inoculation with P. berghei. The results indicate that the aqueous leaf extract of G. barbadense, when used alone as monotherapy, has a non-significant (P ≥ 0.05) but slight suppressive antimalarial activity (23%) when compared with that of chloroquine (100%). The curative model also revealed that aqueous leaf extract of G. barbadense showed no significant antimalarial activity. It can be concluded that the use of aqueous leaf extract of G. barbadense as monotherapy for malaria has no significant therapeutic effect. Therefore, it is not recommended to be used alone to manage malaria infection as practiced by some herbal medicine practitioners.