| Abstract: | 糖尿病 ( diabetes mellitus ) 與胰島素之分泌及作用缺失有相關。高血糖使人體內產生過多活性氧與自由基，造成氧化壓力上升，使相關併發症發生。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。而醣解酵素能參與人體醣類消化作用，並與血糖調節相關，進而影響現代疾病如糖尿病的發生。其中以 α-amylase 及 α-glucosidase 最為重要。中藥材玄參 ( Scrophularia ningpoensis roots ) ，文獻證實具有抗發炎、抗菌、降氧化等生理功能，但對於血糖調控之研究卻相當少，因此本研究擬探討玄參之抗氧化性並評估其對醣解酵素之抑制作用，期望玄參具醣解酵素抑制作用進而對糖尿病顯著改善功效。磨碎的玄參先以甲醇萃取後依序利用正己烷、乙酸乙酯及正丁醇等溶劑與二次去離子水等體積混合後進行液液萃取，並以抗氧化及醣解酵素抑制活性作為篩選依據，進行活性成分之分離、純化及結構鑑定。結果得知玄參正己烷區分物具有較佳醣解酵素抑制活性，但其成分 1H-NMR 光譜鑑定後，大多為不飽和脂肪酸，因此將玄參進行正己烷粗脂肪萃取及 GC 分析，探討其脂肪含量及脂肪酸的種類，並以含相關脂肪酸之油脂和玄參正己烷區分物進行 α-glucosidase 抑制活性比較。結果得知其脂肪酸主要組成為亞麻油酸、油酸、棕櫚酸、硬脂酸及少量的次亞麻油酸 ，另外分析正己烷區分物 α-生育醇含量為16.9 mg/100g，同時多數油脂到達一定含量的體積比例後，皆會對 α-glucosidase 的活性造成顯著性抑制；而玄參乙酸乙酯及正丁醇區分物具有較佳的抗氧化性，經液相管柱層析及 HPLC 分離純化，再經 UV 及 1H-NMR 光譜鑑定後，得知一純化物質，其結構推測為 apigenin 5-O-glucoside；因此推測玄參的抗氧化性或醣解酵素抑制活性為眾多含量甚微的類黃酮或其他活性物質因相乘作用發揮出的活性顯現。
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 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. Roots of Scrophularia ningpoensis family has been used in traditional Chinese medicine for a long time. Previous studies have demonstrated that Scrophularia ningpoensis roots have anti-inflammatory, antibacterial and antioxidant activities. However, possible roles of Scrophularia ningpoensi in hypoglycemic regulation have not been explored yet. In the present study, antioxidative and glycosidase inhibitory components of Scrophularia ningpoensis were identified, and their hypoglycemic activities were then investigated. Scrophularia ningpoensis was extracted with methanol, and the methanol extracts were added distilled deionized water, and then extracted with the proportional n-hexane, ethyl acetate and n-butanol successively. The result showed the n-hexane fraction of Scrophularia ningpoensis.have better glycosidase inhibitory activity. Using 1H-NMR to identified the compositions of Scrophularia ningpoens, and it suggested the n-hexane fraction of Scrophularia ningpoens rich in unsaturated fatty acids. In order to investigate the contents and types of lipids from n-hexane fraction of Scrophularia ningpoens, it was further analysis by crude fat extractiontion and gas chromatography ( GC ). It was found fatty acid compositions are linoleic acid, oleic acid, palmitic acid, stearic acid and a small amount of linolenic acid. In addition,the contents of α-tocopherol were 16.9 mg /100g, and most of the sample oil would significantly inhibit α-glucosidase activity in the same volume. The EtOAc and n-butanol fraction of Scrophularia ningpoensis had better resistance to oxidation, after the separation of the liquid column chromatography and HPLC purified effective active ingredients. Finally, the chemical structures were identified by UV and 1H-NMR, that showed the isolated component was apigenin 5-O-glucoside. According to the data obtained, the compositions in Scrophularia ningpoensis with antioxidant activity and glycosidase inhibitory activity were mainly flavonoids or another active substances . |
