Protective Effects of Olea europaea Fruit Extracts on Metabolic Disorders Associated With Sucrose-Induced Metabolic Syndrome in Rats

Metabolic syndrome (MetS) increases the risk of diabetes. Olea europaea fruit exerts protective effects on metabolic disorders. Therefore, the aim of the present study was to investigate the effect of O. europaea fruit extracts on sucrose-induced MetS in rats. Male adult Wistar rats (200 ± 50 g, n = 32) were randomly divided into four groups (n = 8) consisting of control group, untreated sucrose group (sucrose 50% in drinking water for 10 weeks), sucrose plus aqueous extract of O. europaea fruit treated group (200 mg/kg) and sucrose plus hydroalcoholic extract of O. europaea fruit treated group (200 mg/kg) by gavage for 2 weeks. Body weight, serum glucose, insulin, leptin, lipid profile, homeostatic model assessment of insulin resistance (HOMA-IR) and hepatic enzymes were measured. Data were analyzed by one-way analysis of variance (ANOVA, SPSS, 16.0). P < 0.05 was regarded as significance level. The aqueous extract exhibited higher protective effects on serum glucose, insulin and HOMA-IR than hydroalcoholic extract (P < 0.05). Body weight, serum glucose, leptin (P < 0.01), insulin, triglyceride, very-low-density lipoprotein cholesterol (VLDL-C), HOMA-IR, alkaline phosphatase (ALP), (P < 0.001) and aspartate aminotransferase (AST) (P < 0.05) significantly elevated but high-density lipoprotein cholesterol (HDL-C) (P < 0.05) decreased in the sucrose group. Aqueous extract of O. europaea fruit significantly improved blood glucose, triglyceride, VLDL-C (P < 0.01), insulin, HOMA-IR, ALP (P < 0.001), body weight, AST and leptin (P < 0.05) levels. Hydroalcoholic extract of O. europaea fruit significantly restored insulin, HOMA-IR (P < 0.01), ALP (P < 0.001), body weight, leptin, VLDL-C, triglyceride, blood glucose and AST (P < 0.05). Our results indicated O. europaea fruit extracts could improve metabolic disorders induced by MetS in the rats.