Inhibitory Efficacy of Dioscoreae Rhizoma on MITF, TRP-1, TRP-2, Tyrosinase, PKA and ERK Expression in Melanoma Cells (B16F10)

Abstract

Objectives : The purpose of this study was to research the whitening effects and developing by cosmetics of the extract from Dioscoreae Rhizoma, which is one of the most popular health-promoting herb in herbal medications. Methods : We performed tyrosinase inhibition assay, reverse transcription-polymerase chain reaction (RT-PCR) and western blot for whitening effects. Also we measured MTT assay for cell viability. Results : The results were obtained as follows : For whitening effect, tyrosinase inhibition rate of extract from Dioscoreae Rhizoma showed more than 42.28% at 1,000 ㎍/㎖ concentration. Cell toxicity effect on melanoma cells (B16F10) of extract from Dioscoreae Rhizoma showed 81.97% with toxicity at 50 ㎍/㎖ concentration. So we were measured at a concentrations of 5, 10 and 50 ㎍/㎖ in all experiments involving cell. In addition, whitening related mRNAs including microphthalmia associated transcription factor (MITF), tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2), tyrosinase were reduced by Dioscoreae Rhizoma. We also found Dioscoreae Rhizoma transiently decreased protein kinase A (PKA) which is known to be upstream to the down regulation of MITF and tyrosinase. But phosphorylation of extracellular signal related kinase (pERK) were increased by Dioscoreae Rhizoma. These results imply that Dioscoreae Rhizoma decrease melanogenesis via ERK activation and subsequent down regulation of MITF and tyrosinase. Conclusions : Therefore, all these findings suggested the potent usage of Dioscoreae Rhizoma as materials of functional cosmetics by confirming whitening activity related with melanin content.