Eupofalin, a skin whitening flavonoid isolated from Phyla nodiflora, downregulated melanogenesis: role of MAPK and Akt pathways - Ko, H H; Chiang, Y C; Tsai, M H; Liang, C J; Hsu, L F; Li, S Y; Wang, M C; Yen, F L; Lee, C W (J Ethnopharmacol, 2014)