绞股蓝皂苷-硒配合物对酪氨酸酶的活性影响及动力学分析

为考察绞股蓝皂苷及其硒配合物对酪氨酸酶的动力学参数和作用机理。本研究采用体外酶促反应,以L-酪氨酸和L-DOPA为底物,模拟了酪氨酸酶单酚和二酚酶的体外催化氧化过程。绞股蓝总皂苷在50%、70%乙醇洗脱段和50%、70%乙醇洗脱绞股蓝皂苷-硒配合物在酪氨酸酶上的Ki值分别为1. 533、1. 767、1. 312和1. 210 mmol/L。Ki值越低,对酪氨酸酶的抑制作用越强,单酚酶的氧化阶段越快,表明硒元素显著提高了绞股蓝皂苷对酪氨酸酶的抑制作用。酶反应动力学分析表明,四种绞股蓝皂苷及其硒配合物对酪氨酸的抑制作用均为混合竞争抑制。其独特的药理化学特性为绞股蓝及硒系美白化妆品的进一步研究开发提供了理论依据和参考。

Kinetics and effect of Gypenoside-selenium complex on tyrosinase activity

By in vitro enzymatic reaction,the kinetic parameters and mechanism of Gypenosides on tyrosinase were compared with their selenium-complexes.L-tyrosine and L-DOPA were used as substrates to simulate the catalytic oxidation process of tyrosinase monophenol and diphenol enzyme in vitro.The Ki valures of gypenoside on 50%,70% ethanol elution segments and gypenoside-selenium complexes on 50%,70% ethanol eluting gypenoside on tyrosinase were 1.533,1.767,1.312,and 1.210 mmol/L respectively.The lower Ki value indicated that higher concentrations of Selenium could enhance higher inhibitory effect of Gynostemma pentaphyllum on tyrosinase,otherwise,the oxidation stage of monophenolase was a quick step.The kinetic analysis of enzyme reaction showed that the inhibitory effects of four gypenosides and its selenium-complexes on tyrosine were all mixed-competitive inhibition.The specific pharmacological and chemical characteristics provided a theoretical basis and reference for further research and development of Gynostemma pentaphyllum and selenium related whitening cosmetics.