School of Chinese Materia Medica, Tianjin University of Traditional Chinese Medicine, 10 Poyanghu Road, West Area, Tuanbo New Town, Jinghai District, Tianjin, 301617, P. R. China.
State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyanghu Road, West Area, Tuanbo New Town, Jinghai District, Tianjin, 301617, P. R. China.
Chem Biodivers. 2022 Jan;19(1):e202100740. doi: 10.1002/cbdv.202100740. Epub 2021 Dec 6.
Many stilbene glycosides can alleviate skin hyperpigmentation due to their inhibitory effect on tyrosinase. Mulberrosides in Morus alba L. are stilbene glycosides. In the present study, the inhibition of tyrosinase by five mulberrosides (S1-5), isolated from Morus alba L. was investigated and compared, and the inhibitory mechanism was explored. These five mulberrosides exhibited obvious inhibitory effects on tyrosinase only in a concentration-dependent manner, without time-dependence, indicating that they are reversible inhibitors of tyrosinase. S2, S1 and S5 inhibited tyrosinase activity with IC values of 28.93, 75.94 and 151.72 μM, respectively, and were more active than kojic acid (IC =169.13 μM). Kinetic studies revealed that S1, S2 and S4 were competitive inhibitors, while S3 and S5 were mixed inhibitors. Analysis of the fluorescent spectra showed that mulberrosides S1, S2 and S4 quenched the intrinsic fluorescence intensity of tyrosinase. A molecular docking study indicated that the interaction of tyrosinase with mulberrosides was reflected by compound scores as follows: S2>S5>S1>S3/S4>kojic acid, and hydroxy groups in the side chain of mulberrosides may play a crucial role in the binding of the enzyme. Our results suggest that mulberrosides in Morus alba L. could be further developed as whitening agents for enhanced performance against hyperpigmentation.
许多芪类糖苷由于对酪氨酸酶的抑制作用，可以减轻皮肤色素沉着。桑白皮中的桑多昔是芪类糖苷。本研究对从桑白皮中分离得到的 5 种桑多昔（S1-5）对酪氨酸酶的抑制作用进行了研究和比较，并探讨了其抑制机制。这 5 种桑多昔仅在浓度依赖性方式下对酪氨酸酶表现出明显的抑制作用，没有时间依赖性，表明它们是酪氨酸酶的可逆抑制剂。S2、S1 和 S5 对酪氨酸酶活性的抑制 IC 值分别为 28.93、75.94 和 151.72 μM，比曲酸（IC = 169.13 μM）更具活性。动力学研究表明，S1、S2 和 S4 是竞争性抑制剂，而 S3 和 S5 是混合抑制剂。荧光光谱分析表明，桑多昔 S1、S2 和 S4 猝灭了酪氨酸酶的内源荧光强度。分子对接研究表明，桑多昔与酪氨酸酶的相互作用反映在化合物得分中，结果如下：S2>S5>S1>S3/S4>曲酸，并且桑多昔侧链上的羟基可能在酶的结合中起关键作用。我们的结果表明，桑白皮中的桑多昔可以进一步开发为增白剂，以增强对色素沉着的治疗效果。
