| Summary: | 碩士 === 東海大學 === 食品科學系 === 101 === Diabetes is associated with deficiencies in insulin secretion or action. Excess reactive oxygen species are built up with chronic hyperglycemia, and are subsequently contributing to oxidative stress and related complications. Antioxidants have important roles in disorders involving oxidative stress. Glycosidases are not only involved in human digestion, but also affect the generation of many metabolic diseases such as diabetes, the most important glycosidases are α-amylase and α-glucosidase. Vitis thunbergii, has long been used in traditional Chinese medicine. Previous studies have demonstrated that V. thunbergii have antioxidant, cholesterol-lowering, antibacterial activity. However, possible roles of V. thunbergii stems on hypoglycemic regulation have not yet been explored. In the present study, antioxidative and glycosidase inhibitory components of V. thunbergii stems were identified, and their hypoglycemic activities were also investigated. V. thunbergii stems were extracted with methanol, and the methanol extract was extracted by water with n-hexane, ethyl acetate and n-butanol successively. These extracts were analysed for potential health promoting properties including their inhibitory effects on starch digestive enzymes and antioxidant activities. The n-butanol extract of V. thunbergii stems showed strong antioxidant and inhibitory properties against both α-amylase and α-glucosidase. The extract was further separated successively by Amberlite XAD-7, Comosil 75C18-OPN and reversed HPLC chromatographies to obtain four components. The isolated components were presumed to be uridine、isorhamnetin 7-O-glucoside、kaempferol 7-O-glucoside and quercetin 7-O-glucosid by MS, UV and 1H, 13C-NMR analyses.
|
|---|
