title: Coumarin-Chalcone Hybrids as Peroxyl Radical Scavengers: Kinetics and Mechanisms.
abstract: The primary antioxidant activity of coumarin-chalcone hybrids has been investigated using the density functional and the conventional transition state theories. Their peroxyl radical scavenging ability was studied in solvents of different polarity and taking into account different reaction mechanisms. It was found that the activity of the hybrids increases with the polarity of the environment and the number of phenolic sites. In addition, their peroxyl radical scavenging activity is larger than those of the corresponding nonhybrid coumarin and chalcone molecules. This finding is in line with previous experimental evidence. All the investigated molecules were found to react faster than Trolox with (•)OOH, regardless of the polarity of the environment. The role of deprotonation on the overall activity of the studied compounds was assessed. The rate constants and branching ratios for the reactions of all the studied compounds with (•)OOH are reported for the first time.
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria , I-87036 Arcavacata di Rende, Italy.
authors.forename: Gloria
authors.initials: G
authors.lastname: Mazzone
authors.affiliation: Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa , San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, C. P. 09340 México, D. F. México.
authors.forename: Annia
authors.initials: A
authors.lastname: Galano
authors.affiliation: Departamento de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México , México DF 04510, México.
authors.forename: Juan R
authors.initials: JR
authors.lastname: Alvarez-Idaboy
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria , I-87036 Arcavacata di Rende, Italy.
authors.forename: Nino
authors.initials: N
authors.lastname: Russo
mesh_terms: D002599:Chalcone / Q000737:chemistry*; D003374:Coumarins / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D010545:Peroxides / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D003374:Coumarins; D016166:Free Radical Scavengers; D010545:Peroxides; D012997:Solvents; D014867:Water; C049375:perhydroxyl radical; D002599:Chalcone; C030123:coumarin