Abstract Cashew nut shell liquid (CNSL), extracted from cashew nut shell, is an abundant natural resource. Cardanols were the major phenolic components isolated from CNSL. In this research, we reported on the inhibitory mechanism of cardanols on tyrosinase for the first time. We studied the functions of cardanols and revealed the underlying mechanism of cardanols as tyrosinase inhibitors. Cardanol triene, cardanol diene and cardanol monoene could decrease the steady-state rate of the tyrosinase diphenolase activity efficiently. The IC50 values of three cardanol compounds were determined to be 40.5 ± 3.7, 52.5 ± 3.2 and 56.0 ± 3.6 μM (n = 3), respectively. Meanwhile, the kinetic analysis and the intrinsic/ANS-binding fluoresecence-quenching showed that one cardanol might enter into one tyrosinase. The characteristic values further revealed that cardanols could interact with tyrosinase. Besides, computational study with molecular docking implied that cardanols might affect the amino acid residues of the tyrosinase active site. Collectively, cardanols could moderate inhibitory activities on tyrosinase effectively.

中文翻译：

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腰果酚对酪氨酸酶的抑制机制

摘要 从腰果壳中提取的腰果壳油（CNSL）是一种丰富的自然资源。腰果酚是从 CNSL 中分离出来的主要酚类成分。本研究首次报道了腰果酚对酪氨酸酶的抑制机制。我们研究了腰果酚的功能，并揭示了腰果酚作为酪氨酸酶抑制剂的潜在机制。腰果酚三烯、腰果酚二烯和腰果酚单烯能有效降低酪氨酸酶双酚酶活性的稳态速率。三种腰果酚化合物的 IC50 值分别测定为 40.5 ± 3.7、52.5 ± 3.2 和 56.0 ± 3.6 μM (n = 3)。同时，动力学分析和内在/ANS结合荧光猝灭表明一种腰果酚可能进入一种酪氨酸酶。特征值进一步表明腰果酚可以与酪氨酸酶相互作用。此外，分子对接的计算研究表明腰果酚可能会影响酪氨酸酶活性位点的氨基酸残基。总的来说，腰果酚可以有效地调节对酪氨酸酶的抑制活性。