Tectoridin, an isoflavone glycoside from the flower of Pueraria lobata, prevents acute ethanol-induced liver steatosis in mice

In traditional Chinese medicine, the flower of Pueraria lobata (Puerariae Flos) has been used in therapy to counteract the problems associated with alcohol drinking and liver injury. In this study, we investigated the hepatoprotective effects and its mechanisms of tectoridin, an isoflavone glycoside from the flower of P. lobata (Willd.) Ohwi. Ethanol (5 g/kg) was given orally every 12 h for a total of three doses. 1 h after the last dose of ethanol, tectoridin (25, 50 and 100 mg/kg) was given intragastrically five times in three consecutive days. The mice were sacrificed at 4 h after tectoridin treatment. Peroxisome proliferators-activated receptor α (PPARα), sterol regulatory element-binding protein (SREBP)-1c and their target genes were evaluated by biochemical analysis and quantitative real-time polymerase chain reaction (qPCR). Mitochondria were isolated for the mitochondrial permeability transition (MPT) and membrane potential (ΔΨm) assay. Acute ethanol exposure resulted in the significant increase of the alanine aminotransferase (ALT), aspartate aminotransferase (AST) and triglyceride (TG) levels and hepatic mitochondria dysfunction shown as the increase of MPT and the decrease of ΔΨm. However, tectoridin treatment dramatically attenuated these effects. In addition, tectoridin remarkably alleviated the over-production of thiobarbituric acid-reactive substance. Furthermore, tectoridin inhibited the decrease of PPARα expression and its target genes, including medium-chain acyl-CoA dehydrogenase (MCAD), acyl-CoA oxidase (ACO) and cytochrome P450 4A (CYP 4A) at mRNA and enzyme activity levels. These data showed that tectoridin protected against ethanol-induced liver steatosis mainly through modulating the disturbance of PPARα pathway and ameliorating mitochondrial function.