Cytotoxic and Genotoxic Effects of cis-Tetraammine (oxalato)Ruthenium(III) Dithionate on the Root Meristem Cells of Allium cepa Flávia de Castro Pereira & Cesar Augusto Sam Tiago Vilanova-Costa & Aliny Pereira de Lima & Alessandra de Santana Braga Barbosa Ribeiro & Hugo Delleon da Silva & Luiz Alfredo Pavanin & Elisângela de Paula Silveira-Lacerda Received: 28 August 2008 / Accepted: 29 October 2008 / Published online: 20 November 2008 # Humana Press Inc. 2008 Abstract Ruthenium complexes have attracted much attention as possible building blocks for new transition-metal-based antitumor agents. The present study examines the mitotoxic and clastogenic effects induced in the root tips of Allium cepa by cis-tetraammine(oxalato) ruthenium(III) dithionate {cis-[Ru(C 2 O 2 )(NH 3 ) 4 ] 2 (S 2 O 6 )} at different exposure durations and concentrations. Correlation tests were performed to determine the effects of the time of exposure and concentration of ruthenium complex on mitotic index (MI) and mitotic aberration index. A comparison of MI results of cis-[Ru(C 2 O 2 )(NH 3 ) 4 ] 2 (S 2 O 6 ) to those of lead nitrate reveals that the ruthenium complex demonstrates an average mitotic inhibition Biol Trace Elem Res (2009) 128:258–268 DOI 10.1007/s12011-008-8272-y F. C. Pereira : C. A. S. T. Vilanova-Costa (*) : A. P. Lima : A. S. B. B. Ribeiro : H. D. Silva : E. P. Silveira-Lacerda Laboratório de Genética Molecular e Citogenética, Instituto de Ciências Biológicas–ICB I–Sala 200, Universidade Federal de Goiás, Campus Samambaia (Campus II), Cx. Postal: 2425-0, Goiânia, GO 74690-970, Brazil e-mail: vilanovacosta@gmail.com F. C. Pereira e-mail: pereirafc@gmail.com A. P. Lima e-mail: alinypereiralima@gmail.com A. S. B. B. Ribeiro e-mail: agarbio@gmail.com H. D. Silva e-mail: hugo_bioufg@yahoo.com.br E. P. Silveira-Lacerda e-mail: elacerda@icb.ufg.br L. A. Pavanin Instituto de Química, Universidade Federal de Uberlândia–UFU, Uberlândia, Minas Gerais, Brazil e-mail: pavanin@gmail.com