Effect of GAE on melanogenesis-related proteins and
gene expression
To test whether GAE does regulate the expression of
melanogenesis-related proteins, HEMa-DP cells were
treated with GAE (10 and 20 μg/mL) for 5 days. TYR,
TRP-1, DCT, and MITF levels were assayed by Western
blot (Fig. 4a). Compared with untreated control cells,
GAE treatment at 20 μg/mL significantly reduced TYR,
TRP-1, DCT, and MITF level in a dose-dependent manner
(Fig. 4b-e). Additionally, the effects of GAE on expression
of melanogenic genes were tested using real-time PCR.
mRNA levels of MITF and its downstream genes, TYR,
TRP-1 and DCT, were reduced by GAE (Fig. 4f ). GAE
may contribute to the inhibition of melanogenesis by
regulating the expression of tyrosinase-related genes as
wells as MITF.