In vivo antiplasmodial activity of the methanol leaf extract of Piliostigma reticulatum (Dc.) Hochst (Fabaceae)

Abstract

Abstract Background Piliostigma reticulatum is a plant traditionally used to treat malaria, smallpox, neuralgia, dysentery, diarrhea, and rheumatism in Northern Nigeria. There is no scientific evidence to support the antimalarial activity of this plant. This work aims to investigate the in vivo antiplasmodial activity of the methanol leaf extract of Piliostigma reticulatum (MPR) in mice, infected with NK65 chloroquine-sensitive Plasmodium berghei. The oral lethal doses and preliminary phytochemical screening of the extract were performed. The therapeutic, suppressive, and prophylactic models were used for the antiplasmodial activity at the doses of 250, 500, and 1000 mg/kg of the MPR extract. Chloroquine and artesunate were used as the positive control drugs, while distilled water was used for the negative control group. The antiplasmodial activity was determined by comparing the mean parasite clearance in the treated groups, to the negative control group. Also the effect of the extract on the blood packed-cell volume of mice (PCV) was determined. Results The LD50 of MPR was found to be > 5000 mg/kg. Glycosides, saponins, tannins, flavonoids, triterpenes and alkaloids were the phytochemicals identified in the extract. The extract of MPR produced a significant reduction in the mean parasitemia level compared to the negative control in the curative test: MPR 250 (68.31%, P < 0.001), MPR 500 (76.53%, P < 0.001), and MPR1000 (83.65%, P < 0.001). The extract prolonged the survival of infected mice (18.8 days), compared to the negative control (5.2 days). The extract produced significant chemosuppression compared to the negative control; MPR 250 (73.79%, P < 0.001), MPR 500 (81.33%, P < 0.001), and MPR 1000 (78.37%, P < 0.001). The extract produced significant chemoprophylaxis compared to the negative control; MPR 250 (68.5%, P < 0.001), MPR 500 (58.7%, P < 0.001), and MPR 1000 (84.77%, P < 0.001). The extract was found to have no significant effect on the blood PCV of the treated groups compared to the negative control. Conclusions The study showed that the MPR extract has significant antiplasmodial activity in mice at the doses tested, and could justify the traditional use of the plant in the treatment of malaria in Northern Nigeria.