Main content area

Antiplasmodial and Cytotoxic Triterpenoids from the Bark of the Cameroonian Medicinal Plant Entandrophragma congoënse

Happi, Gervais Mouthé, Kouam, Simeon Fogue, Talontsi, Ferdinand Mouafo, Lamshöft, Marc, Zühlke, Sebastian, Bauer, Jonathan O., Strohmann, Carsten, Spiteller, Michael
Journal of natural products 2015 v.78 no.4 pp. 604-614
Entandrophragma, Plasmodium falciparum, X-ray diffraction, antimalarials, antiparasitic properties, bark, cytotoxicity, inhibitory concentration 50, medicinal plants, nuclear magnetic resonance spectroscopy, rats, triterpenoids, Cameroon
Eight new triterpenoids, prototiamins A–G (1–6, 9) and seco-tiaminic acid A (10), were isolated along with four known compounds from the bark of Entandrophragma congoënse. Their structures were elucidated by means of HRMS and different NMR techniques and chemical transformations. Assignments of relative and absolute configurations for the new compounds were achieved using NOESY experiments and by chemical modification including the advanced Mosher’s method. Additionally, the structure and relative configuration of compound 3 were confirmed by single-crystal X-ray diffraction analysis. Compounds 1, 3, and 5 displayed significant in vitro antiplasmodial activity against the erythrocytic stages of chloroquine-sensitive Plasmodium falciparum strain NF54. Prototiamin C (3) was the most potent of the compounds isolated, with an IC₅₀ value of 0.44 μM. All compounds tested showed low cytotoxicity for the L6 rat skeletal myoblast cell line.