1. Academic Validation
  2. Experimental and theoretical elucidation of structural and antioxidant properties of vanillylmandelic acid and its carboxylate anion

Experimental and theoretical elucidation of structural and antioxidant properties of vanillylmandelic acid and its carboxylate anion

  • Spectrochim Acta A Mol Biomol Spectrosc. 2018 Jun 5;198:61-70. doi: 10.1016/j.saa.2018.02.063.
Dušan Dimić 1 Dejan Milenković 2 Jelica Ilić 1 Biljana Šmit 3 Ana Amić 4 Zoran Marković 5 Jasmina Dimitrić Marković 6
Affiliations

Affiliations

  • 1 Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia.
  • 2 Bioengineering Research and Development Center, Prvoslava Stojanovića 6, 34000 Kragujevac, Serbia.
  • 3 Faculty of Science, University of Kragujevac, Radoja Domanovića 12, 34000 Kragujevac, Serbia.
  • 4 Department of Chemistry, Josip Juraj Strossmayer University of Osijek, Cara Hadrijana 8a, 31000 Osijek, Croatia.
  • 5 Department for Chemical-Technological Sciences, State University of Novi Pazar, Vuka Karadžića bb, 3600 Novi Pazar, Serbia.
  • 6 Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia. Electronic address: markovich@ffh.bg.ac.rs.
Abstract

Vanillylmandelic acid (VMA), an important metabolite of catecholamines that is routinely screened as tumor marker, was investigated by the various spectroscopic techniques (IR, Raman, UV-Vis, antioxidant decolorization assay and NMR). Structures optimized by the employment of five common functionals (M05-2X, M06-2X, B3LYP, CAM-B3LYP, B3LYP-D3) were compared with the crystallographic data. The M05-2X functional reproduced the most reliable experimental bond lengths and angles (correlation coefficient >0.999). The importance of intramolecular hydrogen bonds for structural stability was discussed and quantified by the NBO analysis. The most prominent bands in vibrational spectrum were analyzed and compared to the experimental data. The positions of the carbon and hydrogen atoms in NMR spectra were well reproduced. The differences in UV-Vis spectrum were investigated by adding the explicit solvent and by performing NBO and QTAIM analyses. The discrepancy in the two spectra of about 50nm could be explained by the solvent effect on carboxyl group. The most probable antioxidant activity mechanism was discussed for VMA and its carboxylate anion. The Molecular Docking study with the C - reactive protein additionally proved that variety of functional groups present in VMA and its anion allowed strong hydrogen and hydrophobic interactions.

Keywords

Antioxidant activity; DFT; NBO; QTAIM; Vanillylmandelic acid.

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