Ganocochlearic acid A, a rearranged hexanorlanostane triterpenoid, and cytotoxic triterpenoids from the fruiting bodies of Ganoderma cochlear

Ganocochlearic acid A (1), a rearranged hexanorlanostane triterpenoid featuring a g-lactone ring and a five-membered carbon ring, and eleven new lanostane triterpenoids (2-12), along with six known analogues (13-18) were isolated from the fruiting bodies of Ganoderma cochlear. Their structures, including absolute configurations, were established on the basis of the MS, NMR, X-ray crystallographic, and ECD analysis. A plausible biosynthetic pathway for 1 was proposed. Compounds 7-9, 11-13 showed moderate cytotoxic activities against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480) with IC50 values ranging from 8 to 30 mM. Compound 4 exhibited relatively potent cytotoxic activity against MCF-7 cells (IC50: 9.15 mu M), compared to the positive control (cisplatin, IC50: 12.7 mu M).