XII Iberian Meeting of Electrochemistry XVI Meeting of the ...

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XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PB 10 Cytotoxicity Studies and DN A Interaction of New Ruthenium (II) Cyclopentadienyl Complexes with Nitrogen Coordinated Ligands Tânia S. Morais 1 , M.H. Garcia 1 , M.P. Robalo 2 , A.Valente 1 , V. Moreno 3 , M. Font-Bardia 4 , T. Calvet 4 , J. Lorenzo 5 , F. X. Avilés 5 1 CCMM, FCUL, Campo Grande, 1749-016 Lisboa, Portugal; 2 ADEQ/ISEL, R. Cons. Emídio Navarro, 1, 1959-007 Lisboa; 3 DQI, Univ Barcelona, Martí y Franquès 1-11, 08028, Barcelona, Spain; 4 CMDM, Univ. Barcelona, Martí y Franquès s/n, 08028, Barcelona, Spain; 5 IBB, Univ. Aut. Barcelona, 08193, Bellaterra, Barcelona, Spain tsmorais@fc.ul.pt Ruthenium complexes have been the most widely studied non-Platinum anti-cancer candidates. The search in this field both in coordination and organometallic chemistry has been certainly stimulated by the successful results already obtained with some ruthenium coordination compounds [1,2]. We recently report significant effect of toxicity in LoVo and MiaPaca cells of new -heteroaromatic sigma coordinated ligands [3]. This presentation reports our studies in some new organometallic derivatives belonging to the family of piano stool ruthenium cationic compounds, of general formula [Ru( 5 -C 5 H 5 )(PP)L] + , with PP=phosphanes and L=N-heteroaromatic ligand. An attempt of correlation of the redox potentials of Ru (II) /Ru (III) with cytoxicity of these compounds will be done. Also some results will be presented showing our preliminary studies by cyclic voltammetric of solutions of the new compounds incubated with DNA. The stability of Ru II /Ru III showed by the electrochemical studies suggests the possible existence of Ru(III) analogues of this compounds which potential interest might be their use as bioreductive prodrugs. Figure 1. Cyclic voltammogram of compound [RuCp(PPh 3 -bipy)] [CF 3 SO 3 ] in dichloromethane at sweep rate of 200 mV/s. Acknowledgments: The authors thank to F CT (Project PTDC/QUI/66148/2006) for finantial support; Tânia S. Morais thanks F CT for his Ph.D Grant (SFRH/BD/45871/2008). References [1] Dyson, P.J.; Sava, G.; Dalton Trans., 2006, 1929. [2] Galanski, M.; Arion, V.B; Jakupec, M.A.; Keppler, B.K.; Curr. Pharm. Des., 2003, 9, 2078. [3] Garcia, M.H.; Morais, T.S.; Florindo, P.; Piedade, M.F.M.; Moreno, V.; Ciudad, C; Noe, V.; J. Inorg. Biochem., 2009, 103, 354. September, 811, 2010. ISEL - Lisbon 76
XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PB 11 Acid dissociation constants for several potential anti-tubercular drugs: isoniazid and thiobenzanilide derivatives M. C ristina Ventura, 1,2 A. Catarina Bastos, 1 M. João Sarmento, 1 João Manso, 1 Susana Borges, 1 Vanessa Miranda, 1 Susana Santos, 1 Filomena Martins 1 1 Faculdade de Ciências de Lisboa, Departamento de Química e Bioquímica, Centro de Química e Bioquímica (CQB), Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal 2 Instituto Superior de Educação e Ciências, Alameda das Linhas de Torres, 179, 1750 Lisboa, Portugal mcventura@fc.ul.pt According to the most recent WHO data [1], tuberculosis (TB) kills 1.8 million people every year and one-third of the world's population is currently infected with the Mycobacterium tuberculosis (M.tb) bacillus. Moreover, 9.4 million new TB cases were reported in 2008 from which 1.4 million refer to people co-infected with HIV. Isoniazid (INH) is one of the most powerful first-line drugs in multi-therapeutic regimens but an increasing number of M.tb INH-resistant strains have been reported [2]. The identification of INH derivatives, or derivatives of other families, with antitubercular activity comparable to that of INH but which retain their activity against a panel of INH-resistant strains, would obviously be of invaluable importance [3]. In the process of screening and pre-formulation of potential new drugs, it is essential the knowledge of several physicochemical properties, namely their acid dissociation constants (pKa) which affect the passive transport across biological membranes and therefore the activity in the living organism. However, many of these compounds are scarcely soluble in water, making it necessary to determine their pKa values either in organic solvents or in aqueous mixtures and then extrapolate to water. The rationale of the effect of pK can provide useful information regarding the feasibility of these compounds as drug-like candidates. In this work we performed solubility and stability tests by UV-Vis spectrometry, at 25.0 ºC, for several isoniazid and thiobenzanilide derivatives, some of which designed and synthesized on the basis of QSAR studies. For each compound, pKa values were determined by potentiometry in 4/5 methanol/water mixtures, also at 25.0 ºC. From these values aqueous pKa values were computed by extrapolation using the Yasuda Shedlovsky method. Bioavailability was assessed on the basis of estimated ionization degrees at physiological pH. Acknowledgments: This work was funded under project PTDC/QUI/67933/2006. ACB gratefully acknowledges a BII grant from F CT/F CUL and MJS a grant from UL/Fundação Amadeu Dias, both in 2008/2009. References [1] WHO Report 2009; Global Tuberculosis Control, Epidemiology, Strategy, Financing, Geneve, 2009. [2] Suarez, J.; Ranguelova, K.; Schelvis, J.P.M.; Magliozzo, R.S. J. Biol. Chem., 2009, 284, 16146. [3] Ventura, C.; Martins, F. J. Med. Chem., 2008, 51, 612. September, 811, 2010. ISEL - Lisbon 77
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