Selecting phenolics by means of thermodynamics for scavenging free radicals in camellia oil induced by heating

Phenolics have been employing as promising scavengers for free radicals, theoretical calculation is a convenient method for selecting excellent phenolics. In this study, the efficiencies of 33 phenolics scavenging free radicals were confirmed by means of Bond Dissociation Enthalpy (BDE) of active group and Gibbs Free Energy Change (ΔG) of scavenging reaction computed by Quantum Chemical Calculations. Ultimately, the preferable phenolics were picked out for scavenging free radicals in camellia oil induced by heating. These phenolics scavenged free radicals via Hydrogen Atom Transfer (HAT) mechanism. Specifically, (−)-epigallocatechin gallate (EGCG), myricetin and piceatannol performed the top-ranking efficiencies in camellia oil under 120°C for 50 min, with the inhibition ratios of 75.7 ± 4.1%, 72.9 ± 5.4% and 69.4 ± 11.0%, respectively. The results indicated that the efficiencies of phenolics were predominantly affected by the amount of hydroxyl groups attached to aromatic ring and the BDE of O−H bond. In phenolic acids, the hydroxyl group in ortho-position of the active site was in favor of reinforcing the efficiency. In flavonoids, the hydroxyl group in B-ring and the functional groups of C2=C3 and 4-carbonyl in C-ring were prone to elevating the efficiency.