Tyrosinase inhibitory effect and inhibitory mechanism of tiliroside from raspberry

Tiliroside was found to inhibit both monophenolase and diphenolase activity of mushroom tyrosinase. The lag time of tyrosine oxidation catalyzed by mushroom tyrosinase was obviously lengthened; 0.337 mM of tiliroside resulted in the lag time extension from 46.7 s to 435.1 s. A kinetic analysis shown that tiliroside was a competitive inhibitor for monophenolase and diphenolase with K(i) values of 0.052 mM and 0.26 mM, respectively. Furthermore, tiliroside showed 34.5% (p < 0.05) inhibition of intracellular tyrosinase activity and 54.1% (p < 0.05) inhibition of melanin production with low cytotoxicity on B16 mouse melanoma cells at 0.168 mM. In contrast, arbutin displayed 9.1% inhibition of cellular tyrosinase activity and 29.5% inhibition of melanin production at the same concentration. These results suggested that tiliroside was a potent tyrosinase inhibitor and might be used as a skin-whitening agent and pigmentation medicine.