Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA.
J Agric Food Chem. 2012 Sep 12;60(36):8924-9. doi: 10.1021/jf301147n. Epub 2012 Jun 29.
This study evaluated the inhibitory effects of plant-based extracts (grape seed, green tea, and white tea) and their constituent flavan-3-ol monomers (catechins) on α-amylase and α-glucosidase activity, two key glucosidases required for starch digestion in humans. To evaluate the relative potency of extracts and catechins, their concentrations required for 50 and 90% inhibition of enzyme activity were determined and compared to the widely used pharmacological glucosidase inhibitor, acarbose. Maximum enzyme inhibition was used to assess relative inhibitory efficacy. Results showed that grape seed extract strongly inhibited both α-amylase and α-glucosidase activity, with equal and much higher potency, respectively, than acarbose. Whereas tea extracts and catechin 3-gallates were less effective inhibitors of α-amylase, they were potent inhibitors of α-glucosidase. Nongallated catechins were ineffective. The data show that plant extracts containing catechin 3-gallates, in particular epigallocatechin gallate, are potent inhibitors of α-glucosidase activity and suggest that procyanidins in grape seed extract strongly inhibit α-amylase activity.
本研究评估了植物提取物（葡萄籽、绿茶和白茶）及其组成的黄烷-3-醇单体（儿茶素）对α-淀粉酶和α-葡萄糖苷酶活性的抑制作用，这两种酶是人类淀粉消化所必需的关键糖苷酶。为了评估提取物和儿茶素的相对效力，测定了它们抑制酶活性 50%和 90%所需的浓度，并与广泛使用的药理学葡萄糖苷酶抑制剂阿卡波糖进行了比较。最大酶抑制作用用于评估相对抑制效果。结果表明，葡萄籽提取物强烈抑制α-淀粉酶和α-葡萄糖苷酶的活性，其抑制活性分别与阿卡波糖相当，甚至更高。而茶提取物和儿茶素 3-没食子酸酯对α-淀粉酶的抑制作用较弱，但对α-葡萄糖苷酶的抑制作用较强。非没食子酸儿茶素无效。数据表明，含有儿茶素 3-没食子酸酯的植物提取物，特别是表没食子儿茶素没食子酸酯，是α-葡萄糖苷酶活性的有效抑制剂，并表明葡萄籽提取物中的原花青素强烈抑制α-淀粉酶活性。
