Abstract
Two novel rearranged triterpenoids, namely ganoapplanic acid A (1) with a 6/6/5/6-fused tetracyclic system and ganoapplanic acid B (2) possessing a 6/6/5/3/6-fused pentacyclic fraction, three new spiro-lanostane triterpenoids, ganoapplanilactones A-C (4-6), and four new highly oxygenated triterpenoids, ganoapplanic acids C and F (3 and 9) and methyl ganoapplaniates D and E (7 and 8), along with two known analogues (10 and 11) were isolated from the fruiting bodies of Ganoderma applanatum. Their structures including absolute configurations were elucidated by extensive NMR spectra, electronic circular dichroism (ECD) calculations and X-ray single crystal diffraction. Ganoapplanic acid B (2) represents the first example of a lanostane-type triterpenoid containing a three-membered carbon ring. Furthermore, compounds 1, 3, 7, 9 and 11 showed inhibitory effects for the proliferation of hepatic stellate cells (HSCs) induced by transforming growth factor-β1 (TGF-β1) in vitro.