Hepatoprotective activity of water extracts from chaga medicinal mushroom, inonotus obliquus (Higher basidiomycetes) against tert-butyl hydroperoxide–induced oxidative liver injury in primary cultured rat hepatocytes

We examined the hepatoprotective activity of Inonotus obliquus water extract (IO-W) against tertbutyl hydroperoxide (t-BHP)–induced oxidative liver injury in the primary cultured rat hepatocyte. The 50% radical scavenging concentrations (SC₅₀s) of IO-W for radical-scavenging activity against 2,2′-azino-bis-(3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) were 5.19 mg/mL and 0.39 mg/mL, respectively. IO-W pretreatment to the primary cultured hepatocytes significantly (p<0.05) protected the cells from t-BHP–induced cytotoxic injury even at a low concentration of IO-W (10 μg/mL). The cellular leakage of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH), as well as malondialdehyde (MDA) formation caused by t-BHP were significantly (p<0.05) suppressed by IO-W pretreatment (>100 μg/ mL). In conclusion, this study demonstrates that IO-W exhibited hepatoprotective activity against t-BHP–induced oxidative liver injury in the primary cultured hepatocyte probably via its abilities of quenching free radicals, inhibiting the leakage of ALT, AST, and LDH, and decreasing MDA formation.