Ganoboninketals A–C, Antiplasmodial 3,4-seco-27-Norlanostane Triterpenes from Ganoderma boninense Pat

Three new nortriterpenes, ganoboninketals A–C (1–3), featuring rearranged 3,4-seco-27-norlanostane skeletons and highly complex polycyclic systems were isolated from the medicinal mushroom Ganoderma boninense. The structures of the new metabolites were established by spectroscopic methods. The absolute configurations in 1–3 were assigned by electronic circular dichroism (ECD) calculations. Compounds 1–3 showed antiplasmodial activity against Plasmodium falciparum with IC50 values of 4.0, 7.9, and 1.7 μM, respectively. Compounds 1 and 3 also displayed weak cytotoxicity against A549 cell line with IC50 values of 47.6 and 35.8 μM, respectively. Compound 2 showed weak cytotoxicity toward HeLa cell line with an IC50 value of 65.5 μM. Compounds 1–3 also presented NO inhibitory activity in the LPS-induced macrophages with IC50 values of 98.3, 24.3, and 60.9 μM, respectively.