Lu Yuqin, Zhou Wenyu, Feng Yue, Li Yao, Liu Ke, Liu Lizhong, Lin Dongxu, He Zhendan, Wu Xuli
1 School of Medicine, Shenzhen University , Shenzhen, P.R. China .
2 The First Affiliated Hospital of Shenzhen University (The Second People's Hospital of Shenzhen) , Shenzhen, P.R. China .
J Med Food. 2017 Jun;20(6):577-585. doi: 10.1089/jmf.2016.3910. Epub 2017 May 9.
Acteoside, the predominant polyphenol of small-leaved kudingcha, the Chinese tea, has various biological activities. In this study, we examined the acyl migration of acteoside to isoacteoside with high-temperature treatment of acteoside. The inhibitory effects of acyl-migrated acteoside and acteoside on α-amylase were investigated, as were their binding interaction with α-amylase. The binding of acteoside and isoacteoside to α-amylase was investigated by using the fluorescence spectra assay, circular dichroism, and protein-ligand docking studies. Acteoside was more effective than preheated acteoside and isoacteoside in inhibiting α-amylase activity. Acteoside and isoacteoside binding to α-amylase may induce conformational changes to α-amylase, and the binding site of acteoside and isoacteoside being near the active site pocket of α-amylase may explain the decreased activity of α-amylase. The different affinities and binding sites of acteoside and isoacteoside for α-amylase resulted in different inhibition rates, which may be due to structural differences between acteoside and isoacteoside.
紫丁香苷是中国茶叶小叶苦丁茶中的主要多酚类物质，具有多种生物活性。在本研究中，我们通过对紫丁香苷进行高温处理，研究了其向异紫丁香苷的酰基迁移情况。研究了酰基迁移后的紫丁香苷和紫丁香苷对α-淀粉酶的抑制作用，以及它们与α-淀粉酶的结合相互作用。采用荧光光谱法、圆二色光谱法和蛋白质-配体对接研究等方法，研究了紫丁香苷和异紫丁香苷与α-淀粉酶的结合情况。紫丁香苷在抑制α-淀粉酶活性方面比预热后的紫丁香苷和异紫丁香苷更有效。紫丁香苷和异紫丁香苷与α-淀粉酶的结合可能会引起α-淀粉酶的构象变化，而紫丁香苷和异紫丁香苷的结合位点靠近α-淀粉酶的活性位点口袋，这可能解释了α-淀粉酶活性降低的原因。紫丁香苷和异紫丁香苷对α-淀粉酶的不同亲和力和结合位点导致了不同的抑制率，这可能是由于紫丁香苷和异紫丁香苷之间的结构差异所致。
