Lucidone, a novel melanin inhibitor from the fruit of Lindera erythrocarpa Makino.

The effects of lucidone on tyrosinase and antimelanogenic activity were investigated. Initially, we found that lucidone strongly inhibits the activity of mushroom tyrosinase. The effects of lucidone on tyrosinase were further examined in alpha-MSH-induced B16 melanoma cells. Lucidone significantly inhibits tyrosinase activity and leads to decreased melanin content in cultured B16 melanoma cells. Lucidone also attenuates the expression of tyrosinase and MITF (Microphthalmia-associated Transcription Factor) protein in a concentration-dependent manner, as shown by western blot. Quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR) confirmed that lucidone inhibits the expression of tyrosinase mRNA. Accordingly, the effects of lucidone on the ERK signaling pathway were also investigated, but lucidone was not found to play major role in the induction of ERK activation. Our data indicate that the antimelanogenic activity of lucidone is probably due to its inhibition of tyrosinase activity and the suppression of tyrosinase and MITF expression.