Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology , Tianjin University , Tianjin 300072 , P. R. China.
Department of Pharmaceutical and Pharmacological Sciences , University of Padua , Via Marzolo , 535131 Padua , Italy.
J Agric Food Chem. 2019 Jun 26;67(25):7025-7039. doi: 10.1021/acs.jafc.9b02293. Epub 2019 Jun 18.
As a functional food, the unripe fruits of Rubus chingii Hu have been widely used in China for thousands of years. Twenty-five major ellagitannins (ETs) were identified from the unripe fruits, and a novel ellagitannin, chingiitannin A (1), together with four other known ETs (2-5) were isolated and identified by HPLC-QTOF-MS/MS and 2D-NMR. Chingiitannin A showed the highest α-glucosidase and α-amylase inhibitory activities (IC 2.89 and 4.52 μM, respectively), which occurred in a reversible and noncompetitive manner. Static quenching was indicated in a fluorescence quenching assay. Molecular docking results revealed that chingiitannin A interacted with the enzymes mainly by hydrogen bonding and was bound in the allosteric site. Chingiitannin A was nontoxic, and it increased the glucose uptake in L6 myotubes. The results suggested that the unripe fruits of Rubus chingii Hu are rich sources of ETs, and chingiitannin A might be a good candidate for functional foods or antidiabetic drugs.
作为一种功能性食品，未成熟的悬钩子果实在中国已经被广泛使用了数千年。从未成熟的果实中鉴定出 25 种主要的鞣花单宁（ETs），并通过 HPLC-QTOF-MS/MS 和 2D-NMR 分离和鉴定了一种新型鞣花单宁，即 chingiitannin A（1），以及另外四种已知的 ETs（2-5）。Chingiitannin A 对α-葡萄糖苷酶和α-淀粉酶表现出最高的抑制活性（IC 2.89 和 4.52 μM），呈可逆和非竞争性抑制方式。荧光猝灭实验表明存在静态猝灭。分子对接结果表明，chingiitannin A 主要通过氢键与酶相互作用，并结合在别构部位。Chingiitannin A 无毒性，并且可以增加 L6 肌管中的葡萄糖摄取。结果表明，悬钩子未成熟的果实是 ETs 的丰富来源，并且 chingiitannin A 可能是功能性食品或抗糖尿病药物的良好候选物。
