Abstract
In our research program for discovering novel skin-whitening materials, screening of extracts from flowers of some Prunus species was performed using an anti-tyrosinase assay. Among the tested plants, the flowers of P. persica showed the most potent inhibitory activity. In addition, P. persica also showed suppression of melanogenesis in B16 rat melanoma cells. The active principles of tyrosinase inhibition and suppression of melanogenesis were revealed to be an afzelin (3-O-α-L-rhamnosylkaempferol) and a flavanone, naringenin. The mechanism of the anti-melanogenesis effect of these two compounds was disclosed, for the first time, as the suppression of the expression of tyrosinase protein, which was controlled by the inhibition of phosphorylation of p38 MAPK. These findings show that these compounds could be candidates for the novel molecular target for a skin-whitening agent.