Structural effects on the hesperidin properties obtained by chelation to magnesium complexes

Author(s)

Oliveira, Regina M. M. ^[1] ; de Souza Daniel, Juliana F. ^[2] ; de Aguiar, Inara ^[1] ; das Gracas Fernandes da Silva, Maria Fatima ^[1] ; Fernandes, Joao Batista ^[1] ; Carlos, Rose M. ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Tecnol Fed Parana, BR-86036370 Londrina, PR - Brazil

• Document type: Journal article
• Source: Journal of Inorganic Biochemistry; v. 129, p. 35-42, DEC 2013.
• Web of Science Citations: 12

Abstract

The magnesium complex {[}Mg( hesp)(2)(phen)] (1), where hesp = hesperidin and phen = 1,10'-phenanthroline, was synthesized and characterized by Elemental Analysis (C,H,N), atomic absorption and spectroscopic (FTIR, UV-visible, H-1 NMR) techniques. The congested structure facilitates the tilting and contact of the two hesperidin ligands by hydrogen bonding interactions having a stabilizer effect on the hesperidin. The hydrogen bonds are strongly affected by the solvent used which can lead to changes in the physical-chemical, luminescence and biologic properties of complex 1. Complex 1 is more hydrosoluble (S = 472 +/- 3.05 mu g mL(-1)) and liposoluble (log P = -0.15 +/- 0.01) than free hesperidin (S = 5.92 +/- 0.49 mu g mL(-1), log P = 0.30). Oxidation of the complex in an aqueous solution and room temperature investigated by cyclic voltammetry resulted in a very stable two-electron cyclic process to form the phenoxonium neutral, cation and dication radicals. The stability of the voltammetric process indicates that the species produced are never exhausted and does not lead to changes in the coordination sphere composition. The complex was found to be a better radical scavenger for superoxide radical (IC50 = 68.3 mu M at pH 7.8) than free hesperidin (IC50 = 116.68 mu mol L-1) and vitamin C (IC50 = 852 mu mol L-1). The strong blue fluorescence of complex 1 switches through loss of luminescence in pure water/protic organic solvents or when protected from water (in octanol for example as a model of phospholipid membranes). These features provide an opportunity to map the reactivity of hesperidin in the physiologic medium. In this context, a high uptake of complex into HeLa cells was detected by fluorescence microscopy. The blue fluorescence was uniformly distributed mainly in per nucleic region. (C) 2013 Elsevier Inc All rights reserved. (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 Opportunities: Regular Research Grants
• FAPESP's process: 08/57859-5 - Biorrational control of insect pests
• Grantee: Maria Fátima das Graças Fernandes da Silva
• Support Opportunities: Research Projects - Thematic Grants