Identification and Characterization of the Tyrosinase Inhibitory Activity of Caffeine from Camellia Pollen.
Identification and Characterization of the Tyrosinase Inhibitory Activity of Caffeine from Camellia Pollen.
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DOI：
10.1021/acs.jafc.9b04929
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发表时间：
2019-10
影响因子：
6.1
通讯作者：
Yuanfan Yang;Xu Sun;H. Ni;X. Du;Feng Chen;Zedong Jiang;Qingbiao Li
中科院分区：
文献类型：
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作者：
Yuanfan Yang;Xu Sun;H. Ni;X. Du;Feng Chen;Zedong Jiang;Qingbiao Li
酪氨酸酶抑制剂由于能够调节黑色素的产生，因此在化妆品、医疗和食品工业中非常重要。使用高速逆流色谱和制备型高效液相色谱法从山茶花粉中纯化出酪氨酸酶抑制剂，并通过核磁共振和质谱鉴定为咖啡因。在非竞争性模型中，它表现出很强的蘑菇酪氨酸酶抑制活性，IC50 为 18.5 ± 2.31μg/mL。咖啡因不与酶活性中心的铜离子相互作用，但可以猝灭荧光强度并改变该酪氨酸酶的二级构象。分子动力学模拟表明，咖啡因通过Lys379、Lys 376、Asp357、Glu356、Thr308、Gln307、Asp312和Trp358结合该酪氨酸酶，从而改变L-酪氨酸的结合位点和邻近活性中心的环构象。体外细胞模型分析表明，咖啡因对B16-F10黑色素瘤细胞的细胞内酪氨酸酶活性和黑色素生成均表现出显着的抑制作用，且呈浓度依赖性。这些综合结果表明咖啡因是一种强酪氨酸酶抑制剂，有潜力被开发为化妆品和制药行业的皮肤美白剂或食品工业的抗褐变剂。
Tyrosinase inhibitors are important in cosmetic, medical and food industries due to their regulation of melanin production. A tyrosinase inhibitor was purified from Camellia pollen using high-speed countercurrent chromatography and preparative HPLC and was identified as caffeine by nuclear magnetic resonance and mass spectrometry. It showed strong mushroom tyrosinase inhibitory activity with an IC50 of 18.5 ± 2.31μg/mL in a noncompetitive model. The caffeine did not interact with copper ions in the active center of the enzyme but could quench fluorescence intensity and change the secondary conformation of this tyrosinase. A molecular dynamics simulation showed that caffeine bound this tyrosinase via Lys379, Lys 376, Asp357, Glu356, Thr308, Gln307, Asp312 and Trp358, thus changing the binding sites of L-tyrosine and the loop conformation adjacent to the active center. In vitro cell model analysis revealed that caffeine exhibited significant inhibitory effects on both intracellular tyrosinase activity and melanin production of B16-F10 melanoma cells in a concentration-dependent manner. These comprehensive results suggest that caffeine is a strong tyrosinase inhibitor that has the potentials to be developed as skin-whitening agents in the cosmetics and pharmaceutical industries or as anti-browning agents in food industry.