糖尿病(diabetes mellitus)與胰島素分泌不足或作用缺失相關。高血 糖使體內產生過多活性氧，造成氧化壓力上升及相關併發症發生，抗氧化物質對於活性氧所引發疾病之調控中扮演重要角色。而醣解酵素不但參與人體消化作用，也影響許多代謝疾病如糖尿病的產生，醣解酵素中以α-澱粉?(α-amylase)及α-葡萄醣??(α-glucosidase)最為重要。中藥材小葉山葡萄科(Vitis thunbergii)，文獻證實具有抗氧化、降血脂、抑菌性等生理功能，但對於血糖調控之研究卻相當少，因此本研究探討小葉山葡萄莖之抗氧化性並評估其對醣解酵素之抑制作用，期望小葉山葡萄莖具醣解酵素抑制作用進而對糖尿病顯現改善功效。新鮮中藥材小葉山葡萄莖先以甲醇萃取，再依序利用水、正己烷、乙酸乙酯及正丁醇等溶劑進行液液萃取，並以抗氧化及醣解酵素抑制活性為篩選平台，進行活性成分之分離、純化及結構鑑定。結果得知小葉山葡萄莖正丁醇萃取物的抗氧化及醣解酵素抑制作用較佳，此萃取物接續利用層析膠體(Amberlite XAD-7及Cosmosil 75 C18-OPN)進行區分，再以HPLC純化出4種具抗氧化及醣解酵素抑制活性之純化物質，並利用MS、UV及1H、13C-NMR推測其結構為uridine、isorhamnetin 7-O-glucoside、kaempferol 7-O-glucoside及quercetin 7-O-glucoside。 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.
