Phytoconstituents from Turraea obtusifolia and their antiplasmodial activity

Three new steroids, turranin M, N and O (1-3), together with four known limonoids, nymania 1 (4), rubralin B (5), aphapolynin C (6) and Trichillia substance Tr B (7), were isolated from the leaves of Turraea obtusifolia. Their chemical structures were elucidated using NMR and MS. Rubralin B (5) displayed good activity against the asexual parasites from the drug sensitive Plasmodium falciparum NF54 strain with an IC50 value of 3.47 mu g/mL (4.57 mu M), nymania 1 (4) showed a weak activity (IC50 13.36 mu g/mL (19.40 mu M)) and the rest of compounds had IC50 > 20 mu g/mL. [GRAPHICS] .