Objective: To observe the effect of genistein on A375 cells melanogenesis

and to investigate its correlation with mitogen-activated protein kinase (MAPK) signal pathways. Method: A375 was treated by the different concentrations of genistein for 48 h and the blank group was assigned. The cell activity was assayed by using MTT test. The amount of melanin was detected by using NaOH schizolysis method. The activity of tyrosinase (TYR) was detected by using L-dopa oxidation method. The mRNA expressions of tyrosinase (TYR)

tyrosinase related proteins-1 (TRP-1)

TRP-2

extracellular signal-reg-ulated kinase 1 (ERK1)

ERK2 and c-Jun N terminal kinase 2 (JNK2) RT-PCR were measured by using RT-PCR. Result: Compared with control group

genistein at the safe dose (10-1

10-2

10-3 μmol·L-1) could significantly suppress the melanin formation and activity of TYR of A375 cells. genistein at 1 μmol·L-1 could significantly inhibit the mRNA expressions of TYR

TRP-1

TRP-2

ERK1

ERK2 and JNK2 (P <0.05

P <0.01). Conclusion: It is assumed that genistein could significantly suppress melanogenesis of A375 cells by inhibiting the activity of TYR and down-regulating the expressions of TYR

TRP-1 and TRP-2

the effect may be associated with the expression inhibition of ERK1

ERK2 and JNK2.