Cassiae Semen improves non-alcoholic fatty liver disease through autophagy-related pathway

Objective: Cassiae Semen(CS, Juemingzi in Chinese) has been used for thousands of years in ancient Chinese history for relieving constipation, improving liver function as well as preventing myopia. Here we aimed to elucidate the anti-steatosis effect and underlying mechanism of CS against non-alcoholic fatty liver disease(NAFLD).Methods: High-performance liquid chromatography(HPLC) was used to identify the major components of CS water extract. Mice were fed with a high-fat and sugar-water(HFSW) diet to induce hepatic steatosis and then treated with CS. The anti-NAFLD effect was determined by measuring serum biomarkers and histopathology staining. Additionally, the effects of CS on cell viability and lipid metabolism in oleic acid and palmitic acid(OAPA)-treated HepG2 cells were measured. The expression of essential genes and proteins involved in lipid metabolism and autophagy signalings were measured to uncover the underlying mechanism.Results: Five compounds, including aurantio-obtusin, rubrofusarin gentiobioside, cassiaside C, emodin and rhein were simultaneously identified in CS extract. CS not only improved the diet-induced hepatic steatosis in vivo, as indicated by decreased number and size of lipid droplets, hepatic and serum triglycerides(TG) levels, but also markedly attenuated the OAPA-induced lipid accumulation in hepatocytes.These lipid-lowering effects induced by CS were largely dependent on the inhibition of fatty acid synthase(FASN) and the activation of autophagy-related signaling, including AMP-activated protein kinase(AMPK), light chain 3-II(LC3-II)/LC3-1 and autophagy-related gene5(ATG5).Conclusion: Our study suggested that CS effectively protected liver steatosis via decreasing FASN-related fatty acid synthesis and activating AMPK-mediated autophagy, which might become a promising therapeutic strategy for relieving NAFLD.