THERMODYNAMICALLY INVESTIGATIONS OF FREE RADICAL SCAVENGER POTENCY OF 1,2,4-TRIHYDROXYTHIOXANTHONE

1st International Conference on Chemo and BioInformatics, ICCBIKG  2021, (414-417)

AUTHOR(S) / АУТОР(И): Svetlana R. Jeremić, Jelena R. Đorović Jovanović, Marijana S. Stanojević Pirković, Zoran S. Marković

E-ADRESS / Е-АДРЕСА: sjeremic@np.ac.rs, jelena.djorovic@uni.kg.ac.rs, zmarkovic@uni.kg.ac.rs, marijanas14@gmail.com

Download Full Pdf   

DOI: 10.46793/ICCBI21.414J

ABSTRACT / САЖЕТАК:

The operative mechanism of the antioxidative action of 1,2,4-trihydroxythioxanthone (TX) is investigated in this contribution. Conclusions are made based on enthalpy values, as thermodynamical parameters. All calculations are done using the M06-2X/6-311++G(d,p) level of theory. To imitate polar and non-polar environments, calculations are done in water and benzene as the medium. It is found that, among three possible radicals that TX can generate, the most stable is the one obtained by homolytic cleavage of the O-H group in position 4. It was found that HAT (Hydrogen Atom Transfer) is the most plausible mechanism for that purpose in benzene. On the other hand, the most favorable mechanism in water is SPLET (Sequential Proton Loss Electron Transfer). Here is estimated the capacity of TX to deactivate hydroxyl (HO●), hydroperoxyl (HOO●) and methylperoxyl radical (CH3OO●). It is found that TX can deactivate all three free radicals following HAT and SPLET reaction mechanisms competitively, in the polar and non-polar environment. SET-PT (Single-Electron Transfer followed by Proton Transfer) is the inoperative mechanism for radicals scavenging, in the polar and non-polar environment.

KEY WORDS / КЉУЧНЕ РЕЧИ:

1,2,4-trihydroxythioxanthone, scavenger capacity, free radicals, enthalpy, DFT

REFERENCES / ЛИТЕРАТУРА:

  • Z. Marković, Study of the mechanisms of antioxidative action of different antioxidants, J. Serb. Soc. Comput. Mech., 10 (2016) 135-150.
  • A. Galano, G. Mazzone, R. Alvarez-Diduk, T. Marino, R. Alvarez-Idaboy, N. Russo, Food antioxidants: Chemical insights at the molecular level, Annu. Rev. Food Sci. Technol., 7 (2016) 335-352.
  • C. L. Chen, T.C. Chen, C.C. Lee, L.C. Shih, C.Y. Lin, Y.Y. Hsieh, A.A.A. Alic, H.S. Huang, Synthesis and evaluation of new 3-substituted-4-chloro-thioxanthone derivatives as potent anti-breast cancer agents, Arab. J. Chem., 12 (2019) 3503-3516.
  • M. J. Frisch, et al. (2009) Gaussian 09, Revision A.02. Gaussian, Inc., Wallingford.
  • Y. Takano, K.N. Houk, Benchmarking the Conductor-like Polarizable Continuum Model (CPCM) for aqueous solvation free energies of neutral and ionic organic molecules, J. Chem. Theory Comput., 1 (2005) 70-77.
  • M. Tošović, S. Marković, D. Milenković, Z. Marković, Solvation enthalpies and Gibbs energies of the proton and electron – influence of solvation models, J. Serb. Soc. Comput. Mech., 10 (2016) 66-76.