摘要: 为探究甜茶（Rubus suavissimus）中具有α-葡萄糖苷酶抑制活性的次级代谢产物，该 文利用多种现代色谱分离技术对其干燥叶进行提取分离纯化，综合运用质谱、核磁共振波谱 分析方法确定了单体化合物的结构，同时，对分离得到的化合物进行了α-葡萄糖苷酶抑制 活性的测试。结果表明：（1）从甜茶的干燥叶中分离鉴定出 10 个化合物，分别为甜茶苷（1）、 山奈酚-3-O-洋槐糖苷（2）、没食子酸（3）、二聚松柏醇（4）、5-甲氧基二聚松柏醇（5）、云 实酸（6）、斯替维单糖苷（7）、斯替维醇（8）、16α,17-二羟基对映贝壳杉烷（9）、槲皮素 -3-O-β-D-吡喃半乳糖苷（10），其中化合物 2、4、5、9 为首次从甜茶中分离得到；（2） α-葡萄糖苷酶抑制活性测试结果显示，化合物 2、3、5、6、10 具有较强的α-葡萄糖苷酶 抑制活性。该研究丰富了甜茶中具有α-葡萄糖苷酶抑制活性的化合物，为降血糖相关产品 的开发提供了理论依据。
Abstract: Rubus suavissimus is mainly distributed in Guilin, Liuzhou, Wuzhou and other regions in Guangxi Zhuang Autonomous Region, so it is called as “Guangxi tiancha” in Chinese. R. suavissimus, together with Siraitia grosvenorii and Stevia rebaudianastevia are praised as three famous sweet plants in Guangxi Zhuang Autonomous Region. Zhuang and Yao people use the leaves of R. suavissimus as a tea to treat diabetes, and it is known as the “divine tea” of Yao medicine. Therefore, R. suavissimus is a combination of sugar, tea and medicine, which has great potential for the development of food and medicine. In order to investigate the secondary metabolites with α-glucosidase inhibitory activity from R. suavissimus, herein, the extraction, separation and purification of secondary metabolites were performed on the leaves of R. suavissimus. The structures of purified compounds were determined based on the data of mass spectrometry (HR-ESI-MS) and nuclear magnetic resonance (1H NMR and 13C NMR). In addition, the α-glucosidase inhibitory activity of the purified compounds were evaluated by pharmacological methods simultaneously. The results were as follows: (1) Ten compounds were purified and their structures were elucidated as rubusoside (1), kaempferol 3-O-robinobioside (2), gallic acid (3), dehydroconiferyl alcohol (4), 5-methoxydehydroconiferyl alcohol (5), brevifolincarboxylic acid (6), steviolmonoside (7), steviol (8), 16α, 17-dihydroxykaurane (9), and quercetin 3-O-β-D-galactopyranoside (10). (2) Among them, compounds 2, 4, 5 and 9 were isolated from R. suavissimus for the first time. Compounds 2, 3, 5, 6 and 10 showed strong inhibitory activity on α-glucosidase. The IC50 values of compounds 2, 3, 5, 6 and 10 were (0.14 ± 0.03) mg • mL-1, (0.36 ± 0.02) mg • mL-1, (0.44 ± 0.01) mg • mL-1, (0.53 ± 0.04) mg • mL-1 and (0.14 ± 0.03) mg • mL-1 respectively, which were stronger than the positive control acarbose with the IC50 values as (0.69 ± 0.02) mg • mL-1. Thus, compounds 2, 3, 5, 6 and 10, which were isolated from the leaves of R. suavissimus, could be a potential α-glucosidase inhibitors base on their bioactivity results. Compounds with α-glucosidase inhibitory activity from R. suavissimus will provide the basis for development of hypoglycemic related products.
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