Inhibitory effect of novel tetrahydropyrimidine-2(1H)-thiones on melanogenesis

The series of imidazoldine-2-thiones 2 and tetrahydropyrimidine-2-thiones 3 were discovered as inhibitor of alpha-MSH-induced melanin production in melanoma B16 cells. The primary bioassay showed that 1-(4-ethylbenzyl)-tetrahydropyrimidine-2(1H)-thione 3e (> 100% inhibition at 10 mu M, IC50 = 1.2 mu M) and 1-(4-tert-butylbenzyl)-tetrahydropyrimidine-2(1H)-thione 3f (> 100% inhibition at 10 mu M, IC50 = 0.76 mu M) exhibited potent inhibitory effect against alpha-MSH-induced melanin production. Compounds 3 inhibit the biosynthesis of tyrosinase without affecting its catalytic activity in melanogenesis. (C) 2010 Elsevier Ltd. All rights reserved.