The aqueous extract of Phragmites rhizome improves hepatic steatosis in obese mice via the AMPK-mediated inhibition of ER stress

Phragmites rhizome has been documented to have antioxidative stress and anti-inflammation properties in several pathogenic models. We aimed to investigate the therapeutic effects and molecular mechanism of the aqueous extract of Phragmites rhizome (AP) in in vitro and in vivo hepatic steatosis models. We found that treatment with AP dose-dependently reduced lipid accumulation and endoplasmic reticulum (ER) stress in palmitate-treated human primary hepatocytes and attenuated hepatic steatosis and ER stress in high-fat diet (HFD)-fed mice. AMPK phosphorylation and autophagy markers in hepatocytes were augmented by AP. siRNA targeting AMPK or 3-methyladenine (3-MA) abolished the impacts of AP on palmitate-treated hepatocytes. These results suggest that AP treatment suppresses hepatic ER stress through AMPK/autophagy signaling, leading to attenuation of hepatic steatosis. The present study may provide a novel therapeutic approach for treating nonalcoholic fatty liver disease (NAFLD) and ER stress-mediated metabolic diseases using natural substances.