Identification of triterpenoids and hepatoprotective property of Fructus Rosa roxburghii against alcohol-induced liver injury by regulating keap1- Nrf2 signaling

Background Fructus Rose roxburghii is a popular edible fruit with high nutritional and medicinal value, which was effective on anti-alcohol and liver-protection in southwest China. Purpose The aim of this study was to determine main chemical composition of the extract enriched in triterpenoids from Fructus R. roxburghii (TFRr) using UPLC-MS/MS and to investigate the hepatoprotective effects and molecular mechanisms of TFRr in mice with alcohol-induced liver injury. Methods TFRr were isolated from 75% ethanol extract of Fructus R. roxburghii and chemical constituents of TFRr were analyzed using UPLC-MS/MS. Male Kun-Ming mice were randomly divided into two experimental groups (TFRr groups (50 mg/kg) and TFRr groups (100 mg/kg)) and two control groups (normal control group and 53% ethanol group). Liver injury in mice was induced by oral administration with Lieber-DeCarli liquid diet mixing with 53% ethanol. After 10 days of treatment, the mice were weighed and treated with inhaling diethyl ether to anesthetize, then, the blood and liver tissue samples were gathered for molecular analysis and histological examination. The alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in mice serum and the superoxide dismutase (SOD) activity, glutathione peroxidase (GSH) activity and malondialdehyde (MDA) levels in mice liver were detected by Elisa kits. Western blot analysis was carried out to detect the protein expression levels of nuclear factor-erythroid-related factor-2 (Nrf2), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase regulatory subunit (GCLM), SOD1, glutathione S-transferase (GST) and Keap1 in liver tissues. Results Five triterpenoids (kaji-ichigoside F1, rosamultin, tormentic acid, roxburic acid, and pomonic acid) from TFRr extract were identified. TFRr treatment diminished the effects of LPS on the serum levels of AST and ALT in mice as well as MDA, SOD and GSH in liver. In addition, the protein expression levels of Nrf2 target genes, consisting of HO-1, SOD1, GST, GCLM, and GCLC were significantly upregulated by TFRr suggesting TFRr significantly attenuates the alcohol-induced liver injury by Keap1-Nrf2 signaling pathway. Conclusions These results show TFRr has the profoundly protective roles against ethanol-induced liver injury in mice models via Nrf2-Keap1 signaling pathway. Our results suggested that it is rationale to explore the application of extract enriched with active triterpenoids from Fructus Rosa roxburghii in the development of liver protectants.