杨梅黄素及蛇葡萄素对酪氨酸酶的抑制作用

杨梅黄素及蛇葡萄素对酪氨酸酶有显著的抑制作用；在２ｍｍｏｌ／Ｌ的Ｌ－多巴浓度下，５０％抑制的药物浓度分别为０．０８２ｍｍｏｌ／Ｌ及０．２０８ｍｍｏｌ／Ｌ，用Ｌ－多巴作底物，蛇葡萄素对酪氨酸酶是竞争性抑制，其Ｋ＿ｉ是０．０８５ｍｍｏｌ／Ｌ；而杨梅黄素对酪氨酸酶则是混合性抑制，其Ｋ＿ｉ与Ｋ′＿ｉ分别是０．０２６ｍｍｏｌ／Ｌ与０．０７２ｍｍｏｌ／Ｌ。

Inhibitory Effects of Myricetin and Ampelopsin on Tyrosinase

Tyrosinase was markedly inhibited by myricetin and ampelopsin. The 50% inhibition concentrations of these two inbibitors were 0. 082 mmol/L and 0. 208 mmolL at a L-dopa concentration of 2 mmol/L respectively. The inhibition of ampelopsin on tyrosinase was competitive with K_i value of 0. 085 mmol/L, but the effect of myricetin on tyrosinase was the mixed type of inhibition with K_i and K'_i value of 0. 026 mmol/L and 0. 072 mmol/L,respectively.