Effect of Lanostane Triterpenes from the Fruiting Bodies of Ganoderma lucidum on Adipocyte Differentiation in 3T3-L1 Cells

Two new lanostane triterpenes, methyl lucidenate N (1) and t-butyl lucidenate B (2), were isolated from the fruiting bodies of Ganoderma lucidum together with five known compounds (3-7). The structures of the two new triterpenes were established as methyl 3 beta, 7 beta-dihydroxy-4,4,14 alpha-trimethyl- 11,15-dioxo-5 alpha-chol-8-en-24-oate (1) and t-butyl 7 beta, 12 beta-dihydroxy-4,4,14 alpha-trimethyl-3,11,15-trioxo-5 alpha-chol-8-en-24-oate (2) by extensive spectroscopic studies and chemical evidence. The effect of the isolated compounds (17) on triglyceride (TG) accumulation, an indicator of adipocyte differentiation, during the differentiation of 3T3-L1 preadipocytes was examined. t-Butyl lucidenate B (2) reduced the TG accumulation significantly by 72% at 80 mu M compared to the untreated group. Furthermore, compound 2 effectively suppressed the GPDH activity in the cells. Consistent with the decrease in TG accumulation and GPDH activity, compound 2 suppressed the gene expressions of PPAR gamma, C/EBP alpha, and SREBP-1c in a dose-dependent manner during differentiation. Our findings demonstrate that the lanostane triterpenes isolated in this study contribute to the inhibitory effect of the fruiting bodies of G. lucidum on adipocyte differentiation in 3T3-L1 cells.