Ganocochlearic acid A (1), a rearranged hexanorlanostane triterpenoid featuring a γ-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 μM. Compound 4 exhibited relatively potent cytotoxic activity against MCF-7 cells (IC50: 9.15 μM), compared to the positive control (cisplatin, IC50: 12.7 μM).
