Aphagrandinoids A-D, cycloartane triterpenoids with antibacterial activities from Aphanamixis grandifolia.

Three new cycloartane triterpenoids, aphagrandinoids A-C (1-3), and a new natural product, aphagrandinoid D (4), together with a known compound, were isolated from the leaves and twigs of Aphanamixis grandifolia. Their structures were elucidated by extensive NMR and MS techniques. Aphagrandinoid A (1), a 29-nor-cycloart triterpenoid, features with a sprio ring system at the side chain, while aphagrandinoid C (3) is a pentnortriterpenoid. Antibacterial activities of these five compounds were also evaluated. Compounds 1 and 5 showed weak antibacterial activities (MIC values: 1.57-3.13μg/mL) against Staphylococcus aureus, MRSA 92(#), and MRSA 98(#).