Objective This study aimed to evaluate the antimalarial activity of the extracts and isolated compounds from the stem of Phragmanthera capitata . Methods Aqueous and methanol extracts were prepared from the stem of the plant. The methanol extract was purified via column chromatography to yield friedelin, friedelinol, β-sitosterol and daucosterol. The in vitro anti-plasmodial activity of the extracts and isolated compounds was evaluated against chloroquine-sensitive (3D7) and resistant (Dd2) strains of P. falciparum using the SYBR Green assay and, in vivo antimalarial activity via the Peters’ and Rane’s tests. Results The methanol extract demonstrated superior activity over the aqueous extract, with IC 50 values of 0.84 (3D7) and 1.92 µg/mL (Dd2) in the in vitro antiplasmodial assay. Similarly, daucosterol was the most active compound among the isolated compounds with IC 50 values of 0.84 (3D7) and 2.05 μg/mL (Dd2). The aqueous and the methanol extracts showed comparable suppressive activities in the Peters’ assay with 88% and 89% parasitaemia suppression, respectively. The aqueous extract was more active in the Rane’s curative assay, with 89 % parasitaemia suppression. Friedelin and β-sitosterol displayed similar and remarkable curative potential in the Rane’s assay with % parasitaemia suppression of 85.66 and 86.49, respectively. Conclusion This study validates the Phragmanthera capitata extracts and isolated compounds as antimalarial agents, rationalising the traditional use of the plant to treat malaria. Future work could consider development into antimalarial products, which would contribute to SDG 3 and the Universal Health coverage.
Nketia et al. (2026) studied this question.