Chemistry, Physics and Technology of Surface, 2016, 7 (4), 463-467.

A quantum-chemical study on the antioxidant properties of natural phenolic compounds



DOI: https://doi.org/10.15407/hftp07.04.463

O. O. Kazakova

Abstract


The influence of the structure of flavonolignans (silybin, silychristin), flavonoids (quercetin and taxifolin) on the antioxidant properties of silymarin - a standardized herbal extract obtained from the milk thistle seeds (lat. Silybum marianum), which contains a mixture of these compounds has been studied. Molecular structure was optimized at HF/6-31G(d,p) level of theory by means of the GAMESS program package. The O–H bond dissociation enthalpies for all OH groups and ionization potentials of molecules were calculated using density functional theory approach with B3P86 functional and 6-31G(d,p) basis set to analyze the redox properties. The solvation model IEF PCM was used to account for the solvent effects. It has been shown that the OH groups of the side phenolic ring give the maximum contribution to the hydrogen atom transfer mechanism (HAT). СН2ОН groups and OH groups of flavonoids moieties of silybin and silycristin weakly participate in the HAT (high dissociation enthalpies). The presence of 2,3-double bond in the flavonoid moiety affects the redistribution of charge and increases the contribution of the 3-OH group to a HAT mechanism for the quercetin molecule compared to taxifolin. The contribution of the electron transfer mechanism to the antioxidant activity is reduced in a series of quercetin > silychristin > taxifolin > silybin.

Keywords


flavonolignans; flavonoids; antioxidant activity

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References


1. Nunomura A., Castellani R.J., Zhu X., Moreira P.I., Perry G., Smith M.A. Involvement of oxidative stress in Alzheimer disease. J. Neuropathol Exp. Neurol. 2006. 65 (7): 631. https://doi.org/10.1097/01.jnen.0000228136.58062.bf 

2. Wood-Kaczmar A., Gandhi S., Wood N.W. Understanding the molecular causes of Parkinson's disease. Trends Mol. Med. 2006. 12(11): 521. https://doi.org/10.1016/j.molmed.2006.09.007 

3. Davì G., Falco A., Patrono C. Lipid peroxidation in diabetes mellitus. Antioxid Redox Signal. 2005. 7(1–2): 256. https://doi.org/10.1089/ars.2005.7.256 

4. Khan M.A., Tania M., Zhang D., Chen H. Antioxidant enzymes and cancer. Chin. J. Cancer Res. 2010. 22(2): 87. https://doi.org/10.1007/s11670-010-0087-7 

5. Asghar Z., Masood Z. Evaluation of antioxidant properties of silymarin and its potential to inhibit peroxyl radicals in vitro. Pak. J. Pharm. Sci. 2008. 21(3): 249.

6. Koksal E., Gulcin I., Beyza S., Sarikaya O., Bursal E. In vitro antioxidant activity of silymarin. J. Enzyme Inhib. Med. Chem. 2009. 24(2): 395. https://doi.org/10.1080/14756360802188081 

7. Surai P.F. Silymarin as a Natural antioxidant: an overview of the current evidence and perspectives. Antioxidants. 2015. 4: 204. https://doi.org/10.3390/antiox4010204 

8. Abenavoli L., Capasso R., Milic N., Capasso F. Milk thistle in liver diseases: past, present, future. Phytother. Res. 2010. 24(10): 1423. https://doi.org/10.1002/ptr.3207 

9. Schmidt M.W., Baldridge K.K., Boatz J.A., Elbert S.T., Gordon M.S., Jensen J.H., Koseki Sh., Matsunaga N., Nguyen K.A., Su Sh., Windus Th.L., Dupuis M., Montgomery J.A. The general atomic and molecular electronic structure system. J. Comput. Chem. 1993. 14(11): 1347. https://doi.org/10.1002/jcc.540141112 

10. Trouillas P., Marsal P., Siri D., Lazzaroni R., Duroux J.L. A DFT study of the reactivity of OH groups in quercetin and taxifolin antioxidants: the specificity of the 3-OH site. Food Chem. 2006. 97(4): 679. https://doi.org/10.1016/j.foodchem.2005.05.042 

11. Cances M. T., Mennucci B., Tomasi J. A new integral equation formalism for the polarizable continuum model: Theoretical background and applications to isotropic and anisotropic dielectrics. J. Chem. Phys. 1997. 107(8): 3032. https://doi.org/10.1063/1.474659 

12. Parr R.G., Donnelly R.A., Levy M., Palke W.E. Electronegativity: The density functional viewpoint. J. Chem. Phys. 1978. 68: 3801. https://doi.org/10.1063/1.436185 

13. Kazakova O.A. Interaction of bioactive molecules with highly dispersed silica surface in aqueous medium: quantum chemical investigation. Surface. 2011. 3(18): 13. [in Russian]




DOI: https://doi.org/10.15407/hftp07.04.463

Copyright (©) 2016 O. O. Kazakova

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