State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, PR China.
Food Funct. 2021 Nov 29;12(23):11862-11871. doi: 10.1039/d1fo02173g.
In this study, the mechanisms of the delay of starch digestion by luteolin were revealed by studying the luteolin-PPA (porcine pancreatic α-amylase) interaction and luteolin-starch interaction. The luteolin-PPA interaction was investigated by inhibitory kinetics analysis, fluorescence quenching, circular dichroism (CD), Fourier transform infrared (FT-IR) spectroscopy and molecular docking. The results of the inhibitory kinetics revealed that luteolin was a mixed-type inhibitor of PPA and that the inhibitory action was reversible. Fluorescence spectroscopy (including fluorescence quenching and thermodynamics) and molecular docking analyses indicated that hydrogen bonds and hydrophobic forces were the main forces between PPA and luteolin. CD and FT-IR spectroscopy analyses showed that the interaction between luteolin and PPA changed the secondary structure of PPA and induced a decline in its activity. In addition, the luteolin-starch interaction was also studied using UV-visible absorption and X-ray diffraction analyses. These indicated that luteolin could bind with PPA, and that hydrogen bonds and van der Waals forces may be present. Overall, luteolin delayed starch digestion not only by binding with PPA but also by binding with starch. Thus, luteolin has the potential to prevent and control diabetes by being added into starch-based food to delay starch digestion.
在这项研究中，通过研究木樨草素与 PPA（猪胰α-淀粉酶）的相互作用和木樨草素与淀粉的相互作用，揭示了木樨草素延缓淀粉消化的机制。通过抑制动力学分析、荧光猝灭、圆二色性（CD）、傅里叶变换红外（FT-IR）光谱和分子对接研究了木樨草素与 PPA 的相互作用。抑制动力学研究结果表明，木樨草素是 PPA 的混合抑制剂，抑制作用是可逆的。荧光光谱（包括荧光猝灭和热力学）和分子对接分析表明，氢键和疏水作用力是 PPA 与木樨草素之间的主要作用力。CD 和 FT-IR 光谱分析表明，木樨草素与 PPA 的相互作用改变了 PPA 的二级结构并导致其活性下降。此外，还通过紫外-可见吸收和 X 射线衍射分析研究了木樨草素与淀粉的相互作用。这些表明木樨草素可以与 PPA 结合，氢键和范德华力可能存在。总的来说，木樨草素通过与 PPA 结合以及与淀粉结合来延缓淀粉消化，从而有可能通过添加到淀粉类食物中来预防和控制糖尿病。
