The aim of the present study was to investigate the effect of black sesame seeds ethanol extract (BSSEE) against nonalcoholic fatty liver disease (NAFLD) in fructose-fed mice. Mice were fed a standard diet without or with 30% fructose in drinking water for 8 consecutive weeks, while mice in three BSSEE tested groups received different doses of BSSEE (0.5, 1, and 2 mL/kg) once a day from the fifth week to the eighth week. Administration of BSSEE dose-dependently exerted antiobesity and protective effect against metabolism disorder in fructose-fed mice. Histological examinations indicated that administration of BSSEE obviously reduced hepatic lipid accumulation. Insulin tolerance test (ITT) and glucose tolerance test (GTT) along with decreases of serum insulin and glucose levels by BSSEE treatment suggested the improvement of body insulin resistance, and administration of 1 and 2 mL/kg BSSEE mitigated liver insulin resistance as the evidence of downregulated expression of phospho-JNK1/2/3, phospho-NF-κB p65, phospho-IRS1, and phospho-IKK alpha/beta, up-regulated XBP1 expression, and reductions of TNF-α and IL-6 levels. In addition, BSSEE treatment ameliorated hepatic oxidative stress through increasing GSH, vitamin C, and Nrf2 levels, decreasing MDA and NO levels, and enhancing SOD, CAT, and GSH-Px activities. These results demonstrated that BSSEE showed protective effects against NAFLD-related metabolic diseases in fructose-fed mice. Therefore, BSSEE may be a potent dietary supplement to ameliorate the diseases.
Keywords: black sesame seeds; fructose; hepatic oxidative stress; insulin tolerance; nonalcoholic fatty liver disease.