Antioxidant activities, a-glucosidase inhibitory effect in vitro and antihyperglycemic of Trapa acornis shell in alloxan-induced diabetic rats

Abstract

Activity of Trapa acornis shell (TAS), including antioxidant and α-glucosidase inhibitory activity, was assayed in vitro. Extracts of ethyl acetate (EtOAC) (TASEA) and n-butanol (n-BuOH) (TASBU) were studied on protective effects of alloxan-induced diabetic rats in vivo. The antioxidant activity was determined by the method of 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzo-thiazoline-6-sulfonicacid) (ABTS) and ferric reducing antioxidant power (FRAP) assay. α-Glucosidase inhibitory activity was screened by 96-microplate-based method. The results showed that TASEA had the highest antioxidant activity (DPPH: IC50=1.88±0.04 μg/ml, ABTS: IC50=1.02±0.04 μg/ml and FRAP=8578.25±59.15 μmol TE/g). TASEA had the highest α-glucosidase inhibitory activity (IC50 =0.42±0.02 μg/ml). Compared with diabetic control mice, administration of TASEA (1200 and 400 mg/kg) and TASBU (1000 and 300 mg/kg) significantly decreased the level of fasting blood glucose (FSG), postprandial blood glucose (PBG) and malondialdehyde (MDA). Oral administration of TASEA and TASBU could decrease the level of triglyceride (TG) without statistical significance. TASEA (1200 mg/kg) could significantly increase liver glycogen content and decreased the level of total cholesterol (TC) and TASBU (1000 mg/kg) could significantly increase the level of superoxide dismutase (SOD) in serum. The results indicate that TASEA and TASBU had signii¬cant antihyperglycemic effects in alloxan-induced diabetic rats. Key words: Trapa acornis shell, antioxidant activity, α-glucosidase inhibitory activity, antihyperglycemic, diabetes.