Glycyrrhiza flavonoids and its major component, licochalcone A, inhibit melanogenesis through MAPK/ERK pathway by activating ERK phosphorylation

Melanin is synthesized mainly by melanocytes that are located in the basal layer of the epidermis and its formation is associated with tyrosinase and dopachrome tautomerase activities [1]. And tyrosinase plays an important role in melanogenesis which can catalyze the hydroxylation of tyrosine to 3, 4-L-dihydroxyphenylalanine (DOPA) and further oxidation of DOPA to dopaquinone [2]. Microphthalmia-associated transcription factor (MITF) is a basic helix-loop-helix leucine zipper transcription factor, which can control the expression of various genes for normal melanin synthesis in melanocytes [3].