Antioxidant and amine oxidase inhibitory activities of hydroxyurea.

Hydroxyurea (HU, NH(2)CONHOH), or hydroxycarbamide, is a hydroxamic acid derivative used as a drug for anti-neoplasm and sickle-cell disease. In this study, HU was found to have antioxidant activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals and dose-dependent inhibitory activities against monoamine oxidase (MAO)-A, MAO-B, and semicarbazide-sensitive amine oxidase (SSAO) as compared to controls of clorgyline, deprenyl, and semicarbazide respectively. HU showed mixed-type, competitive-type, and competitive-type inhibition, respectively, with respect to substrates of MAO-A, MAO-B, and SSAO with apparent inhibition constants (Ki) of 19.46, 5.38, and 1.84 microM.