Analogues of N-hydroxy-N'-phenylthiourea and N-hydroxy-N'-phenylurea as inhibitors of tyrosinase and melanin formation.

A series of N-hydroxy-N'-phenylthiourea and N-hydroxy-N'-phenylurea analogues were prepared and evaluated as inhibitors of tyrosinase and melanin formation. The most active analogue 1 inhibited mushroom tyrosinase with an IC(50) of around 0.29 microM and also retained a substantial potency in cell culture by reducing pigment synthesis by 78%. Therefore, compound 1 could be considered as a promising candidate for preclinical drug development for skin hyperpigmentation application.