Phenolic acid and flavonoid-rich fraction of Sasa quelpaertensis Nakai leaves prevent alcohol induced fatty liver through AMPK activation

Abstract

Ethnopharmacological relevance: Sasa quelpaertensis Nakai is an edible dwarf bamboo cultivated mainly in Jeju Island, South Korea and its leaf displays various health-promoting properties including antioxidant scavenging.

Aim of the study: In this study, we aimed at elucidating its hepatoprotective effect against alcohol-induced fatty liver.

Methods: In in vitro study, we evaluated the cytotoxicity and hepatoprotective effect of different solvent fractions (aqua, butanol, chloroform, ethyl acetate and hexane) of 80% EtOH extract of S. quelpaertensis Nakai leaf. In vivo experiment performed using binge alcohol consumption model.

Results: Although all five fractions (0-1000 µg/mL) were non-cytotoxic to HepG2 cells, only ethyl acetate fraction (SQEA), rich in phenolic acids such as p-coumaric acid and flavonoids particularly myristin, showed hepatoprotective effect against EtOH (400 mM) in HepG2 cells. Furthermore, SQEA significantly decreased the ethanol induced cell death and enhanced the cell proliferation. In in vivo experiment using binge consumption model (5 g of EtOH/kg body weight in every 12 h for 3 times), SQEA treatment (10, 50 and 100 mg/kg) markedly reduced the alcohol induced histopathological changes and serum EtOH content, and reversed the reduction of glutathione level in ethanol challenged livers. Further, it suppressed the expression of cytochrome P450 2E1 (CYP2E1). In particular, SQEA activated AMP activated protein kinase (AMPK) pathway, and decreased the expression of tumor necrosis factor receptor-1 (TNFR1), which attenuated lipogenesis via decreased expression of fatty acid synthase (FAS). Inhibited lipogenesis due to SQEA treatment directed towards decreased perilipin-2 expression. These results indicate that SQEA has hypolipidemic effect which is mediated by decreased oxidative stress, increased fatty acid oxidation response and decreased lipogenesis.

Conclusion: Our results suggest the possibility of developing SQEA as a natural hepatoprotective agent potent in attenuating alcohol-induced fatty liver.

Keywords: Alcohol; Fatty acid; Fatty liver; HepG2 cells; Hepatotoxic.