Department of Food and Life Science, Pukyong National University, Busan 48513, Republic of Korea.
Department of Food Science and Human Nutrition, Chonbuk National University, Jeonju 54896, Republic of Korea.
Food Chem. 2019 Mar 15;276:383-389. doi: 10.1016/j.foodchem.2018.10.008. Epub 2018 Oct 9.
Traditionally, the root of Pueraria lobata are widely used as a functional food. It was observed that a 70% ethanol extract showed a dose-dependent inhibition towards mushroom tyrosinase. Among the different isolated compounds, calycosin demonstrated potent inhibitory activity against substrates l-tyrosine and l-DOPA, with IC of 1.45 ± 0.03 and 7.02 ± 0.46 µM, respectively. Conversely, formononetin and daidzein exhibit weak inhibition. Moreover, kinetic studies revealed calycosin to be a competitive inhibitor for both substrates. Additionally, molecular docking simulation showed that the hydroxyl groups at C-3' and C-7 positions interacted with the catalytic site and peripheral residues, demonstrating a higher affinity toward mushroom tyrosinase. Accordingly, our results suggest that, rather than a mono-substituted hydroxyl or methoxyl group, the presence of a hydroxyl group at C-3' and a methoxyl group at C-4' position of the isoflavone skeleton plays an essential role in the manifestation of anti-browning activity in food products.
传统上，野葛的根部被广泛用作功能性食品。研究发现，70%的乙醇提取物对蘑菇酪氨酸酶表现出剂量依赖性抑制作用。在不同分离得到的化合物中，芒柄花素对底物 l-酪氨酸和 l-DOPA 表现出很强的抑制活性，IC 分别为 1.45±0.03 和 7.02±0.46µM。相反，芒柄花苷和大豆苷表现出较弱的抑制作用。此外，动力学研究表明芒柄花素对两种底物均为竞争性抑制剂。此外，分子对接模拟表明，C-3'和 C-7 位的羟基与催化位点和外围残基相互作用，表现出对蘑菇酪氨酸酶更高的亲和力。因此，我们的结果表明，在食品的抗褐变活性中，异黄酮骨架上 C-3'位的羟基和 C-4'位的甲氧基的存在，而不是单取代的羟基或甲氧基，起着至关重要的作用。
