College of Life Science and Key Laboratory of Functional Small Organic Molecule, Ministry of Education, Jiangxi Normal University, Nanchang, Jiangxi 330022, People's Republic of China.
Food Funct. 2019 Jan 22;10(1):99-111. doi: 10.1039/c8fo01979g.
Condensed tannins contained in food are known to have many beneficial impacts on human health. In this study, we attempt to evaluate the structural features, antityrosinase effects, anti-melanogenesis properties, antioxidant activity and DNA damage protection activity of condensed tannins purified from the seeds of Vigna angularis (Willd.) Ohwi et Ohashi. MALDI-TOF MS, ESI-Full-MS, and HPLC-ESI-MS demonstrated that condensed tannins are composed of procyanidins, prodelphinidins and their gallates, among which procyanidins are the dominant components. As reversible and mixed-type inhibitors of tyrosinase, condensed tannins from V. angularis strongly inhibited the monophenolase and odiphenolase activities with IC50 values of 130.0 ± 0.5 and 35.1 ± 2.0 μg mL-1, respectively. What's more, condensed tannins had a good inhibitory effect on cell proliferation, cellular tyrosinase activity, and melanogenesis of B16 mouse melanoma cells. Based on fluorescence quenching analyses, these compounds were determined to be effective quenchers of the enzyme and its substrates. According to molecular docking, the strong interaction between condensed tannins and tyrosinase was mainly driven by hydrogen bonding and hydrophobic force. In addition, condensed tannins showed a powerful antioxidant capacity and DNA damage protection activity. Therefore, condensed tannins from V. angularis have feasible applications in food, medicine, and the cosmetics industry.
食物中的缩合单宁已知对人类健康有许多有益的影响。在这项研究中，我们试图评估从 Vigna angularis (Willd.) Ohwi et Ohashi 种子中纯化的缩合单宁的结构特征、酪氨酸酶抑制作用、抗黑色素生成特性、抗氧化活性和 DNA 损伤保护活性。MALDI-TOF MS、ESI-Full-MS 和 HPLC-ESI-MS 表明，缩合单宁由原花青素、原花青素及其没食子酸酯组成，其中原花青素是主要成分。作为酪氨酸酶的可逆和混合型抑制剂，来自 V. angularis 的缩合单宁强烈抑制单酚酶和邻二酚酶活性，IC50 值分别为 130.0 ± 0.5 和 35.1 ± 2.0 μg mL-1。此外，缩合单宁对 B16 小鼠黑色素瘤细胞的增殖、细胞酪氨酸酶活性和黑色素生成有很好的抑制作用。基于荧光猝灭分析，这些化合物被确定为酶及其底物的有效猝灭剂。根据分子对接，缩合单宁与酪氨酸酶之间的强相互作用主要由氢键和疏水作用力驱动。此外，缩合单宁表现出强大的抗氧化能力和 DNA 损伤保护活性。因此，来自 V. angularis 的缩合单宁在食品、医药和化妆品行业具有可行的应用前景。
