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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Synthesis, spectroscopic characterization, photochemical and photophysical properties and biological activities of ruthenium complexes with mono- and bi-dentate histamine ligand

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Cardoso, Carolina R. [1] ; de Aguiar, Inara [1] ; Camilo, Mariana R. [1] ; Lima, Marcia V. S. [1] ; Ito, Amando S. [2] ; Baptista, Mauricio S. [3] ; Pavani, Christiane [3] ; Venancio, Tiago [1] ; Carlos, Rose M. [1]
Total Authors: 9
[1] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil
[2] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, BR-05508 Sao Paulo - Brazil
[3] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-01498 Sao Paulo - Brazil
Total Affiliations: 3
Document type: Journal article
Source: DALTON TRANSACTIONS; v. 41, n. 22, p. 6726-6734, 2012.
Web of Science Citations: 7

The monodentate cis-{[}Ru(phen)(2)(hist)(2)](2+) 1R and the bidentate cis-{[}Ru(phen)(2)(hist)](2+) 2A complexes were prepared and characterized using spectroscopic (H-1, (H-1-H-1) COSY and (H-1-C-13) HSQC NMR, UV-vis, luminescence) techniques. The complexes presented absorption and emission in the visible region, as well as a tri-exponential emission decay. The complexes are soluble in aqueous and non-aqueous solution with solubility in a buffer solution of pH 7.4 of 1.14 x 10(-3) mol L-1 for (1R + 2A) and 6.43 x 10(-4) mol L-1 for 2A and lipophilicity measured in an aqueous-octanol solution of -1.14 and -0.96, respectively. Photolysis in the visible region in CH3CN converted the starting complexes into cis-{[}Ru(phen)(2)(CH3CN)(2)](2+). Histamine photorelease was also observed in pure water and in the presence of BSA (1.0 x 10(-6) mol L-1). The bidentate coordination of the histamine to the ruthenium center in relation to the monodentate coordination increased the photosubstitution quantum yield by a factor of 3. Pharmacological studies showed that the complexes present a moderate inhibition of AChE with an IC50 of 21 mu mol L-1 (referred to risvagtini, IC50 181 mu mol L-1 and galantamine IC50 0.006 mu mol L-1) with no appreciable cytotoxicity toward to the HeLa cells (50% cell viability at 925 mu mol L-1). Cell uptake of the complexes into HeLa cells was detected by fluorescence confocal microscopy. Overall, the observation of a luminescent complex that penetrates the cell wall and has low cytotoxicity, but is reactive photochemically, releasing histamine when irradiated with visible light, are interesting features for application of these complexes as phototherapeutic agents. (AU)

FAPESP's process: 09/08218-0 - New Mn(I)-photosentizer complexes: mimicking the electron donor side of photosystem II in artificial photosynthesis
Grantee:Rose Maria Carlos
Support type: Regular Research Grants