Hepatoprotective effect of ganoderma triterpenoids against oxidative damage induced by tert-butyl hydroperoxide in human hepatic HepG2 cells

Context: Ganoderma triterpenoids (GTs) have been recognised as an important bioactive ingredient in Ganoderma Lucidum (Leyss. ex Fr.) Karst. (Polyporaceae), widely used for treating and preventing chronic hepatopathy of various etiologies.

Objective: The objective of this study is to better understand the hepatoprotective effect of GTs and to enhance their use in food supplement pharmaceutical and medical industries.

Materials and methods: HepG2 cells were pretreated in the presence or absence of GTs (50, 100 and 200 μg/ml) for 4 h, then exposed with 60 μmol/L of t-BHP for an additional 4 h. The cell viability was evaluated by MTT method. ALT, AST and LDH production in culture medium and intracellular MDA, GSH and SOD levels were determined. Moreover, the total triterpenoid content and chemical constituents in GTs were detected by ultraviolet spectrophotometry and HPLC/Q-TOF-MS, respectively.

Results: GTs (50, 100 and 200 μg/ml) significantly increased the relative cell viability by 4.66, 7.78 and 13.46%, respectively, and reduced the level of ALT by 11.44%, 33.41% and 51.24%, AST by 10.05%, 15.63% and 33.64%, and LDH by 16.03%, 23.4% and 24.07% in culture medium, respectively. GTs could also remarkably decrease the level of MDA and increase the content of GSH and SOD in HepG2 cells. Furthermore, the total triterpenoid content in GTs was 438 mg GAAEs/g GTs. And 16 triterpenoids in GTs were identified or tentatively characterised.

Discussion and conclusion: Our results showed that GTs had potent cytoprotective effect against oxidative damage induced by t-BHP in HepG2 cells, thus suggesting their potential use as liver protectant.