Disclosed is use of a compound of the formula (I) to increase the amount of melanin in melanocytes, where: R1 is formula (AA) in which, X is H, CH3, (CH2)n—CH3 or a substituted alkyl group, Y is H, CH3, (CH2)n—CH3 or a substituted alkyl group and Z is H or OH; and R2 is H, OH, NH2 or —O—(OH2)nβ where, n=1 to 3 and β is phenyl, naphthyl or alkyl group further optionally substituted with halogen, aryl or NH2 group, where compound of formula 1 is not a compound in which X is H, Y is CH3 and Z is OH.