Chai Wei-Ming, Huang Qian, Lin Mei-Zhen, Ou-Yang Chong, Huang Wen-Yang, Wang Ying-Xia, Xu Kai-Li, Feng Hui-Ling
College of Life Science and Key Laboratory of Small Functional Organic Molecule, Ministry of Education, Jiangxi Normal University , Nanchang, Jiangxi 330022, People's Republic of China.
Zigong Innovation Center of Zhejiang University , Zigong, Sichuan 643000, China.
J Agric Food Chem. 2018 Jan 31;66(4):908-917. doi: 10.1021/acs.jafc.7b05481. Epub 2018 Jan 22.
In this study, the content, structure, antityrosinase activity, and mechanism of longan bark condensed tannins were evaluated. The findings obtained from mass spectrometry demonstrated that longan bark condensed tannins were mixtures of procyanidins, propelargonidins, prodelphinidins, and their acyl derivatives (galloyl and p-hydroxybenzoate). The enzyme analysis indicated that these mixtures were efficient, reversible, and mixed (competitive is dominant) inhibitor of tyrosinase. What's more, the mixtures showed good inhibitions on proliferation, intracellular enzyme activity and melanogenesis of mouse melanoma cells (B). From molecular docking, the results showed the interactions between inhibitors and tyrosinase were driven by hydrogen bond, electrostatic, and hydrophobic interactions. In addition, high levels of total phenolic and extractable condensed tannins suggested that longan bark might be a good source of tyrosinase inhibitor. This study would offer theoretical basis for the development of longan bark condensed tannins as novel food preservatives and medicines of skin diseases.
本研究对龙眼树皮缩合单宁的含量、结构、抗酪氨酸酶活性及作用机制进行了评估。质谱分析结果表明，龙眼树皮缩合单宁是原花青素、原花翠素、原花青定及其酰基衍生物（没食子酰基和对羟基苯甲酸酯）的混合物。酶分析表明，这些混合物是酪氨酸酶的高效、可逆且混合型（以竞争性为主）抑制剂。此外，该混合物对小鼠黑色素瘤细胞（B16）的增殖、细胞内酶活性及黑色素生成均有良好的抑制作用。分子对接结果显示，抑制剂与酪氨酸酶之间的相互作用是由氢键、静电和疏水相互作用驱动的。此外，较高水平的总酚和可提取缩合单宁表明，龙眼树皮可能是酪氨酸酶抑制剂的良好来源。本研究将为龙眼树皮缩合单宁开发新型食品防腐剂和皮肤病药物提供理论依据。
