engleski

Radical scavenging potency of 4- hydroxyphenylpropionic acid: a theoretical approach

Health benefits of polyphenol-rich diet are related to intestinal metabolites, rather than to polyphenolic compounds originally present in food [1, 2], which usually possess very low bioavailability and low systemic concentration [3, 4]. Particular intestinal metabolites are produced in high M concentrations and may promote health via several possible in vivo mechanisms [5]. 4-hydroxyphenylpropionic acid (4-HPPA) is among the most abundant products of polyphenols degradation in large intestine [5]. Its concentration in colon may reach value of 200 M [5], which could be sufficient to exert biological activity and effective direct radical inactivation. Radical scavenging mechanisms of 4-HPPA, in water and pentyl ethanoate as a solvent, were studied by DFT method using Gaussian 09 package [6]. Geometry optimizations and frequency calculations were carried out using the M06– 2X/6-311++G(d, p) level of theory, in conjunction with the SMD continuum solvation model. Hydrogen atom transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms were found to be thermodynamically probable and competitive processes in both media. The Gibbs free energy change for reaction of inactivation of radicals indicates 4-HPPA as a potent scavenger. 4-HPPA possesses potential for inactivating radicals of different characteristics by direct scavenging via HAT and SPLET mechanisms. Because 4-HPPA is produced in high M concentrations and is usually better absorbed than its precursor molecules, it may contribute to health benefits associated with regular intake of polyphenol- rich diet. References [1] Y.S. Chiou, J.C. Wu, Q. Huang, F. Shahidi, Y.J. Wang, C.T. Ho and M.H. Pan, J. Funct. Foods 7 (2014) 3-25. [2] A. Duda-Chodak, T. Tarko, P. Satora and P. Sroka, Eur. J. Nutr. 54 (2015) 325-341. [3] D. Del Rio, A. Rodriguez-Mateos, J.P.E. Spencer, M. Tognolini, G. Borges and A. Crozier, Antioxid. Redox Signal. 18 (2013) 1818-1892. [4] P.C.H. Hollman, Arch. Biochem. Biophys. 559 (2014) 100-105. [5] B. Halliwell, J. Rafter and A. Jenner, Am. J. Clin. Nutr. 81 (2005) 268S−276S. [6] M.J. Frisch, G.W. Trucks, H.B. Schlegel et al., GAUSSIAN 09, Wallingford, CT, 2009. Acknowledgments We gratefully acknowledge the financial support to this work from The Foundation of the Croatian Academy of Sciences and Arts, under the project No. 10-102/244-1- 2016. – "Investigations of the antioxidant mechanisms of polyphenols and their metabolites"

radical scavenging ; 4-hydroxyphenoylpropionic acid ; DFT ; HAT ; ET-PT ; SPLET

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