Figure 6

Galloyl-RGD effectively inhibits tyrosinase, thus retarding the appearance of intermediates of melanin synthesis. (a) Tyrosine conversion to L-DOPA. After 48 h in the presence of 1000 ppm galloyl-RGD, DOPA appearance in the treated group was inhibited to 43.8%. (b) DOPA conversion to dopaquinone (an oxidized form of L-DOPA and a melanin precursor). After 48 h in the presence of 1000 ppm galloyl-RGD, L-DOPA oxidation in the treated group was decreased to 54.4%. * p < 0.01 vs. 0 ppm group; # p < 0.01 vs. 0 ppm group to 50 ppm group; $ p < 0.01 vs. all groups.