The inhibitory effect of black soybean on hepatic cholesterol accumulation in high cholesterol and high fat diet-induced non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is defined as excess of fat in the liver. We investigated the effects of black soybean on the cholesterol metabolism and insulin resistance of mice fed high cholesterol/fat diets. Mice were randomly allocated into four groups that were fed different diets: the normal cholesterol/fat diet; high cholesterol/fat diets (HCD); and HCD with 1%, and 4% black soybean powder (1B-HCD, and 4B-HCD). Liver total cholesterol and triglyceride concentrations were significantly lower in the black soybean-supplemented groups than that in the HCD group. PCR revealed significantly lower hepatic SREBP2 and HMG-CoA reductase mRNA levels of black soybean-supplemented mice. Real-time PCR revealed significantly higher hepatic ABCA1 mRNA level of black soybean-supplemented mice, which may increase cholesterol efflux. Liver bile acids concentration was significantly high in the 4B-HCD group. Black soybean stimulated secretion of adiponectin, activation of pAMPK, and eliminated free fatty acids in the liver. Black soybean supplementation decreased MDA and nitrate level. The activities of SOD, catalase, and GPx were restored by black soybean supplementation. Our data strongly indicate that black soybean influences the balance between oxidative and antioxidative stress. We suggest that black soybean improves cholesterol metabolism, insulin resistance, and alleviates oxidative damage in NAFLD.