Kim Ik-Soo, Yoon Sung-Jin, Park Young-Jun, Lee Hee-Bong
Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea.
Cell Therapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea.
Biochim Biophys Acta. 2015 Jul;1850(7):1389-96. doi: 10.1016/j.bbagen.2015.04.001. Epub 2015 Apr 7.
Melanogenesis, a process producing the pigment melanin in human skin, eyes and hair, is a major physiological response against various environmental stresses, in particular exposure to ultraviolet radiation, and its pathway is regulated by a key enzyme, tyrosinase. In this study, we evaluated the effects of ephedrannins A and B, which are polyphenols from the roots of Ephedra sinica, commonly used in herbalism in oriental countries, on mushroom tyrosinase and melanogenesis in B16F10 melanoma cells.
Their effects on mushroom tyrosinase were determined via kinetic studies using a spectrophotometric analysis and those on melanin and tyrosinase production in melanoma cells treated with α-MSH (melanin stimulating hormone) were examined using PCR and ELISA.
Both ephedrannins A and B exhibited concentration-dependent inhibitory effects on L-tyrosine oxidation by mushroom tyrosinase, and the inhibition mechanism was competitive and reversible with L-tyrosine as the substrate. In addition, melanin production in melanoma cells was also suppressed in a concentration-dependent manner by ephedrannins A and B without significant effects on cell proliferation at the concentrations tested. Both compounds showed inhibitory effects on melanin production by suppressing the transcription of tyrosinase in the cells.
Both compounds exhibited significant inhibitory effects, but the inhibition by ephedrannin B was much more effective than that by ephedrannin A. Both ephedrannins A and B may be good candidates for a whitening agent for skin.
This is the first report that describes effective inhibition of melanin production by ephedrannins A and B isolated from Ephedra roots.
黑色素生成是在人类皮肤、眼睛和毛发中产生色素黑色素的过程，是针对各种环境应激的主要生理反应，尤其是暴露于紫外线辐射时，其途径由关键酶酪氨酸酶调节。在本研究中，我们评估了麻黄宁A和B（它们是来自麻黄根的多酚，在东方国家常用于草药）对蘑菇酪氨酸酶以及B16F10黑色素瘤细胞中黑色素生成的影响。
通过使用分光光度分析的动力学研究确定它们对蘑菇酪氨酸酶的影响，并使用PCR和ELISA检测它们对用α - 黑素细胞刺激激素（MSH）处理的黑色素瘤细胞中黑色素和酪氨酸酶产生的影响。
麻黄宁A和B对蘑菇酪氨酸酶催化的L - 酪氨酸氧化均表现出浓度依赖性抑制作用，并且以L - 酪氨酸为底物时，抑制机制是竞争性且可逆的。此外，麻黄宁A和B还以浓度依赖性方式抑制黑色素瘤细胞中的黑色素生成，在所测试的浓度下对细胞增殖无显著影响。两种化合物均通过抑制细胞中酪氨酸酶的转录而对黑色素生成表现出抑制作用。
两种化合物均表现出显著的抑制作用，但麻黄宁B的抑制作用比麻黄宁A更有效。麻黄宁A和B都可能是皮肤美白剂的良好候选物。
这是首次报道从麻黄根中分离出的麻黄宁A和B有效抑制黑色素生成。
