To study the inhibitory effect of floridoside in red algae on the generation of melanin, the B16-F0 melanoma cells were used to evaluate the ability of floridoside on the biosynthesis of melanin. The effect of floridoside on the activity of tyrosinase was also detec-ted for investigating the mechanism. Results indicated that floridoside showed no obvious toxicity to B16-F0 melanoma cells, but sup-pressed melanogenesis with the concentration dependence manner. Floridoside was discovered to inhibit both the monophenolase and the o-diphenolase activities. It influenced the steady state of monophenolase activity and IC50 was 89 mmol/L. The inhibition on o-di-phenolase activity was in a concentration dependent manner, and 40 mmol/L floridoside reduced the steady state activity for 33. 08%. The inhibition kinetics analyzed by Lineweaver-Burk plots showed that floridoside was a reversible competitive inhibitor, and the inhibi-tion constant was determined to be 16. 44 mmol/L for the free enzyme. In general, floridoside was potential to suppress the generation of melanin, and the mechanism was to inhibit the activity of tyrosinase, especially the activity of o-diphenolase.%探索红藻糖苷对生物体黑色素产生的抑制作用.利用黑素瘤细胞B16-F0评价红藻糖苷对细胞合成黑色素的影响;从抑制酪氨酸酶酶活角度研究其抑制机理.研究显示,红藻糖苷对黑素瘤细胞无明显细胞毒性,但呈浓度依赖性抑制细胞黑色素产生.红藻糖苷对酪氨酸酶的单酚酶和二酚酶活性都有抑制作用,单酚酶的IC50为89 mmol/L;对二酚酶的抑制为可逆竞争性抑制,Ki为16.44 mmol/L.可见,红藻糖苷具有抑制细胞生成黑色素的能力,其机理与抑制酪氨酸酶活性有关.
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