THEORETICAL INVESTIGATION OF CERTAIN TEA COMPOUNDS IN AQUEOUS AND BLOOD PHASES
Öz
In this study, certain theoretical properties of tea compounds, such as acidity constant, stability, reactivity, geometry and energy have been calculated prior to laboratory studies to understand the basic principles concerning their behaviors within the human body by MOPAC2009 with the PM6 method. The order of proton dissociation, dipole moment and nucleophilicity for the studied molecules in aqueous and blood phases were investigated. The order of stabilities of the molecules was determined in relation to the Gibbs free energy. It is observed that any molecule having more of the -OH group has more stability and is less reactive. The stabilities of all the molecules are higher in the aqueous phase than those in the blood phase. Their calculated acidity constants were compared with those of experimental values. Positive meaningful correlations (R2> 0.9999) were observed between thermokinetic pKa values for 1c, 2ec, 3cg, 4ecg, 5egc, 6egcg and 7ga in both aqueous and blood phases.
Anahtar Kelimeler
Catechins, Polyphenol, Tea, Theoretical calculation, PM6, Marvinbeans, Sparc
Kaynakça
- AnaMarı´a,M.W.andDaniel,G.M.(2006).Theoreticalstudyofthemolecularproperties and chemical reactivity of (+)-catechin and -)-epicatechin related to their antioxidant ability. Journal of Mo- lecular Structure (Theochem) 761, 97-106.
- Anh,Y.J.,Kawamura,T.,Kim,M.,Yamamoto,T. and Mitsuoka, D. (1991). Tea Polyphenols: Selective Growth Inhibitors of Clostridium spp. Agricultural and Biological Chemistry 55, 14251426.
- Adams, M.L., O’Sullivan, B., Downard, A. and Powell, K.J. (2002). Stability Constants for Aluminum(III)Complexes with the 1,2-Dihydroxyaryl Ligands Caffeic Acid, Chlorogenic Acid, DHB, and DASA in Aqueous Solution. Journal of Chemical Engineering Data 47, 289-296.
- Hatano, T., Yoshida, T. and Hemingway, R.W. (1999). In: Gross, et al. (eds.) Plant Polyphenols 2: Chemistry, Biology, Pharmacology, Ecology; Kluwer, New York.
- Herrero-Martínez, J.M., Sanmartin, M., Rosés, M., Bosch, E. and Ràfols, C. (2005). Determination of dissociation constants of flavonoids by capillary electrophoresis. Electrophoresis 26, 1886- 1895.
- Inoue, M.B., Inoue, M., Fernando, Q., Valcic, S. and Timmermann, B.N. (2002). Potentiometric and 1H NMR studies of complexation of Al3+ with (-)-epigallocatechin gallate, a major active constituent of green tea. Journal of Inorganic Biochemistry 88, 7-13.
- Jankun, J., Selman, S.H., Swiercz, R. and Skrzypczak-Jankun, E. (1997). Why drinking green tea could prevent cancer. Nature 387, 561.
- Ji, H.F., Zhang, H.Y. Shen, L. (2006). Proton dissociation is important to understanding structure– activity relationships of gallic acid antioxidants. Bioorganic & Medicinal Chemistry Letters 16, 4095-4098.
- Kondo, K., Kurihara, M., Miyata, N., Suzuki, T. and Toyoda, M. (1999). Mechanistic Studies of Catechins as Antioxidants against Radical Oxidation. Archives of Biochemistry and Biophysics 362, 79-86.
- Kris-Etherton, P.M. and Keen, C.L. (2002). Evidence that the antioxidant flavonoids in tea and cocoa are beneficial for cardiovascular health. Current Opinion in Lipidology 13, 41-49.