In the present study, the natural flavonoid luteolin 5-O-β-d-glucopyranoside isolated from the Korean thistle, Cirsium japonicum var. maackii (Maxim.) Matsum., for the first time, found to be a strong competitive inhibitor against mushroom tyrosinase (IC₅₀ = 2.95 ± 0.11 μM, K_i = 3.02 μM for l-tyrosine; IC₅₀ = 8.22 ± 0.18 μM, K_i = 11.56 μM for l-3,4-dihydroxyphenyl-alanine), which outperformed luteolin and 5-deoxy luteolin (3′,4′,7-trihydroxyflavone), showing noncompetitive and competitive inhibition only in l-tyrosine, respectively, emphasizing the importance of glycosylation at 5-OH position of luteolin. Furthermore, molecular modeling of luteolin 5-O-β-d-glucopyranoside showed strong H-bond interaction with Arg268 and peroxide ion (Per402) present between the copper ions. Additionally, the luteolin 5-O-β-d-glucopyranoside–tyrosinase complex was stabilized by electrostatic and hydrophobic interactions formed with key catalytic residues; however, in luteolin, these were lacking. Therefore, Cirsium maackii may act as an important anti-tyrosinase remedy because of the amount and potency of the active compounds luteolin 5-O-β-d-glucopyranoside and luteolin.

中文翻译：

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发现一种强效酪氨酸酶抑制剂，木犀草素5 - O -β-d-葡糖苷，从日本皮草分离。maackii（Maxim。）Matsum。，朝鲜蓟：动力学和计算分子对接模拟

在本研究中，从朝鲜蓟Cirsium japonicum var中分离出天然黄酮类木犀草素5- O- β- d-吡喃葡萄糖苷。maackii（Maxim。）Matsum。首次发现是抗蘑菇酪氨酸酶的强竞争性抑制剂（IC ₅₀ = 2.95±0.11μM，l-酪氨酸的K _i = 3.02μM； IC ₅₀ = 8.22±0.18μM，l -3,4-二羟基苯基丙氨酸的K _i = 11.56μM ，其优于木犀草素和5-脱氧木犀草素（3'，4'，7-三羟基黄酮），仅在l中显示出非竞争性和竞争性抑制作用-酪氨酸分别强调木犀草素在5-OH位置糖基化的重要性。此外，木犀草素5- O- β- d-吡喃葡萄糖苷的分子模型显示出与Arg268和铜离子之间存在的过氧化物离子（Per402）的强H键相互作用。此外，木犀草素5 - O - β - d-吡喃葡萄糖苷-酪氨酸酶复合物可通过与关键催化残基形成的静电和疏水相互作用来稳定。然而，在木犀草素中，这些缺乏。因此，由于活性化合物木犀草素5- O- β- d-吡喃吡喃糖苷和木犀草素的量和效力，大果枸杞（Cirsium maackii）可以作为重要的抗酪氨酸酶药物。