da Silva, Monize M.de Camargo, Mariana S.Castelli, Silviade Grandis, Rone A. [UNESP]Castellano, Eduardo E.Deflon, Victor M.Cominetti, Marcia R.Desideri, AlessandroBatista, Alzir A.2020-12-122020-12-122020-03-01Journal of the Brazilian Chemical Society, v. 31, n. 3, p. 536-549, 2020.1678-47900103-5053http://hdl.handle.net/11449/200311Herein we present four new ruthenium(II) complexes: [Ru(mtz)2(dppb)] (1), [Ru(mmi)2(dppb)] (2), [Ru(dmp)2(dppb)] (3), and [Ru(mpca)2(dppb)] (4), where mtz = 2-mercaptothiazoline; mmi = 2-mercapto-1-methyl-imidazole; dmp = 4,6-diamino-2 - m e r c a p t o p y r i m i d i n e; m p c a = 6 - m e r c a p t o p y r i d i n e - 3 - c a r b o x y l i c a c i d; dppb = 1,4-bis(diphenylphosphino)butane. In vitro cell culture experiments revealed cytotoxic activity for complexes 2, 3 and 4 against MCF-7 (breast, non-invasive), MDA-MB-231 (breast, invasive), A549 (lung), DU-145 (prostate) and HepG2 (liver) tumor cells, in some cases lower than the half maximal inhibitory concentration (IC50) for the reference drug (cisplatin). The deoxyribonucleic acid (DNA) interactions studied by viscosity measurements, gel electrophoresis and square-wave voltammetry indicated that the DNA binding affinity primarily occurs through non-covalent interactions. Only complex 2 was able to fully inhibit the DNA supercoiled relaxation mediated by human topoisomerase IB (Top IB). The analysis indicates that complex 2 inhibits the cleavage and the reconnection steps of the catalytic cycle, being both a poison and a catalytic inhibitor.536-549engCytotoxicityMercapto ligandsRuthenium(II) complexesTopoisomerase IBArtigo10.21577/0103-5053.20190214S0103-50532020000300536Acesso aberto2-s2.0-85083674896S0103-50532020000300536.pdf