N-(3,5-Dihydroxybenzoyl)-6-hydroxytryptamine as a Novel Human Tyrosinase Inhibitor That Inactivates the Enzyme in Cooperation with L-3,4-Dihydroxyphenylalanine
作者:Yoshimitsu Yamazaki、Yasuhiro Kawano
DOI:10.1248/cpb.58.1536
日期:——
N-(3,5-Dihydroxybenzoyl)-6-hydroxytryptamine (2) was a novel inhibitor of L-3,4-dihydroxyphenylalanine (DOPA) oxidase activity of human HMV-II melanoma tyrosinase. The IC50 values for 2 and three reference compounds, N-(3,5-dihydroxybenzoyl)serotonin, 6-hydroxyindole, and kojic acid, were 9.1, 842, 22, and 310 μM, respectively, indicating that the 6-hydroxyindole moiety was more effective than 5-hydroxyindole as the pharmacophore of polyphenolic tyrosinase inhibitors and that the inhibitory activity of 6-hydroxyindole was strengthened by the link with a resorcinol group. Furthermore, compound 2 exhibited a unique property of inactivating the human tyrosinase in the presence of low concentrations of DOPA. This inactivation was attenuated by high concentrations of DOPA and for the most part was irreversible as confirmed by activity stain in native polyacrylamide gel electrophoresis and by removal of 2 and DOPA using gel permeation chromatography. Tyrosinase is the enzyme that oxidizes tyrosine to DOPA and further oxidizes DOPA to the melanin precursor dopaquinone. A compound such as 2 that inactivates the enzyme in the presence of a small amount of DOPA is therefore attractive as a new type of tyrosinase inhibitor. Unfortunately, 2 hardly suppressed the melanogenesis in melanoma cell culture. However, the above strong inhibitory activity and the unique property in the combination with DOPA suggest that this compound is a useful lead in designing new antimelanogenic agents.
N-(3,5-二羟基苯甲酰基)-6-羟基色胺 (2) 是人 HMV-II 黑色素瘤酪氨酸酶的 L-3,4-二羟基苯丙氨酸 (DOPA) 氧化酶活性的新型抑制剂。 2 种和 3 种参考化合物 N-(3,5-二羟基苯甲酰基)5-羟色胺、6-羟基吲哚和曲酸的 IC50 值分别为 9.1、842、22 和 310 μM,这表明6-羟基吲哚部分作为多酚酪氨酸酶抑制剂的药效团比5-羟基吲哚更有效,并且6-羟基吲哚的抑制活性通过与间苯二酚基团的连接而得到加强。此外,化合物 2 表现出在低浓度多巴存在下使人酪氨酸酶失活的独特特性。这种失活被高浓度的 DOPA 减弱,并且大部分是不可逆的,这通过天然聚丙烯酰胺凝胶电泳中的活性染色以及使用凝胶渗透色谱法去除 2 和 DOPA 证实。酪氨酸酶是将酪氨酸氧化为多巴并进一步将多巴氧化为黑色素前体多巴醌的酶。因此,在少量多巴存在下使酶失活的诸如2之类的化合物作为新型酪氨酸酶抑制剂是有吸引力的。不幸的是,2几乎不能抑制黑色素瘤细胞培养物中的黑色素生成。然而,上述强抑制活性和与多巴结合的独特性质表明该化合物是设计新的抗黑色素生成剂的有用先导。