Alleviative effect of Ruellia tuberosa L. on NAFLD and hepatic lipid accumulation via modulating hepatic de novo lipogenesis in high-fat diet plus streptozotocin-induced diabetic rats

Ruellia tuberosa L. (RTL) exhibits phytochemical activities and has been used as a folk medicine for curing diabetes mellitus in East Asia for decades. This study investigated the effect of RTL aqueous and ethanolic extracts on nonalcoholic fatty liver disease (NAFLD) and hepatic lipid accumulation in high-fat diet (HFD) and streptozotocin (STZ)-induced type 2 diabetes mellitus (T2DM) rats. Administration of RTL aqueous extract (RTLW) or ethanolic extract (RTLE) at dosage of 100 or 400 mg/kg body weight for 4 weeks was carried out in HFD/STZ-induced T2DM rats. Liver weight, adipose (epididymal and perirenal adipose tissues) weight, hepatic triglyceride level, and de novo lipogenesis (DNL)-associated protein expression were monitored after scarification. The results revealed that RTLW and RTLE reduced relative liver weight and relative fat weights in HFD/STZ-induced T2DM rats. RTLW and RTLE also ameliorated NAFLD and hepatic triglyceride (TG) accumulation in diabetic rats. Moreover, hepatic DNL-regulated enzymes such as sterol regulatory element-binding protein-1 (SREBP1) and fatty acid synthase (FAS) expression were significantly suppressed by RTLE (100 and 400 mg/kg body weight) in diabetic rats. The evidences of this study suggest that RTL possesses potential on alleviating NAFLD and lipid accumulation via regulating DNL in the liver of HFD/STZ-induced T2DM rats.