Synthesis, cytotoxicity, and DNA-topoisomerase inhibitory activity of new asymmetric ureas and thioureas Original Research Article

A new series of N-3,3-diphenylpropyl-N-(p-X-benzyl)-N′-phenylureas (5a–g) and thioureas (6a–g) were synthesized by the reaction of secondary amines and phenyl isocyanate or isothiocyanate. The cytotoxic effects of the urea and thiourea derivatives were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against Ehrlich carcinoma and K562 human leukemia cells. Moreover, the activity of compounds in the inhibition of DNA topoisomerases I and II-α was tested. The results indicated that the compounds presented important and promising antiproliferative action.