Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore.
J Agric Food Chem. 2010 Jan 13;58(1):148-54. doi: 10.1021/jf903011g.
Current work investigated the ability of different tea (green, oolong and black teas) in inhibiting human salivary alpha-amylase (HSA) and mammalian alpha-glucosidase (AGH). The inhibitory profiles were correlated to their major polyphenol content (theaflavins and catechins). The fully fermented black tea was demonstrated to be most potent in inhibiting HSA and AGH (IC50 of 0.42 to 0.67 and 0.56 to 0.58 mg of tea leaves/mL respectively). Its capability in retarding the digestion of a real food system (rice noodle) was further elucidated with an in vitro digestion study. Results indicated that black tea was able to retard starch digestion moderately, thereby allowing a gradual reduction of sugar liberation. Polyphenolic profile analysis suggested that the oxidized catechins, theaflavins, may be responsible for its activity. We have found that refractive index (RI) measurement is a rapid, direct, and highly convenient method for quantifying the degree of enzymatic starch digestion and kinetics. The RI method has good linearity range, limit of detection (0.1596 mg/mL, maltose equivalent) and limit of quantitation (0.6312 mg/mL) and was successfully applied in our study.
目前的工作研究了不同茶（绿茶、乌龙茶和红茶）抑制人唾液α-淀粉酶（HSA）和哺乳动物α-葡萄糖苷酶（AGH）的能力。抑制谱与它们的主要多酚含量（茶黄素和儿茶素）相关。结果表明，全发酵的红茶在抑制 HSA 和 AGH 方面最为有效（IC50 分别为 0.42 至 0.67 和 0.56 至 0.58mg 茶叶/mL）。通过体外消化研究进一步阐明了其在延缓真实食物系统（米粉）消化方面的能力。结果表明，红茶能够适度延缓淀粉消化，从而逐渐减少糖的释放。多酚谱分析表明，氧化的儿茶素、茶黄素可能是其活性的原因。我们发现折射率（RI）测量是一种快速、直接和非常方便的方法，可用于定量测定酶解淀粉的程度和动力学。RI 法具有良好的线性范围、检测限（0.1596mg/mL，麦芽糖当量）和定量限（0.6312mg/mL），并已成功应用于我们的研究。
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