Aglycone of Rh4 inhibits melanin synthesis in B16 melanoma cells: possible involvement of the protein kinase A pathway.

To our knowledge, there is no report that directly shows an inhibitory effect of ginsenoside on melanin synthesis in B16 melanoma cells. Hence, we investigated whether the aglycone of Rh(4) (A-Rh4) inhibits melanin synthesis in B16 melanoma cells, and determined the mechanism of melanin inhibition. We isolated 12 ginsenoside compounds from leaves of Panax ginseng and tested them in B16 melanoma cells.