Protective effects of triterpenoids from Ganoderma resinaceum on H2O2-induced toxicity in HepG2 cells

Ganoderma resinaceum Boud. (Polyporeseae) has long been used for antioxidant, immunoregulation and liver protection. From the fruiting bodies of G. resinaceum, eight new lanostanoids, lucidones D–G (1–4), 7-oxo-ganoderic acid Z2 (5), 7-oxo-ganoderic acid Z3 (6), ganoderesin A (7), and ganoderesin B (8), together with six known lanostanoids (9–14) were isolated. The structures of new compounds were elucidated through extensive spectroscopic analysis. In an in vitro model, ganoderesin B (8), ganoderol B (10) and lucidone A (11) showed inhibitory effects against the increase of ALT and AST levels in HepG2 cells induced by H2O2 compared to a control group in the range of their maximum non-toxic concentration (MNTC). However, compounds 8, 10 and 11 displayed no anti-oxidant activities by DPPH assay. Meanwhile, activation for PXR (Pregnane X Receptor) of ganoderesin B (8), ganoderol B (10) and lucidone A (11) was evaluated; ganoderol (10) exhibited a vital activation for PXR-induced CYP3A4 expression. These results suggested that GTs (Ganoderma triterpenoids) exhibited hepatoprotective activities by lowering ALT and AST levels.