Thermodynamic and kinetic studies of the antiradical activity of 5-hydroxymethylfurfural: computational insights.

5-Hydroxymethylfurfural (HMF) is a natural product derived from the degradation of sugars in e.g. milk, honey and raisins. Recent studies have shown that this compound has several beneficial physiological effects including antioxidant activity. In the present paper, the antiradical properties of 5-HMF were systematically investigated by using the M06-2X/6-311++G(d,p) model chemistry in the gas phase, in water solution and, for a lipid-mimetic environment, in pentyl ethanoate solvent. The thermodynamic and kinetic modelling of the reactions of 5-HMF with a range of reactive oxidative species revealed that 5-HMF scavenges HO˙ and HOO˙ radicals. The overall rate constants for the HO˙ radical scavenging in the gas phase and water and pentyl ethanoate solvents are 2.39 × 10¹², 5.92 × 10⁹ and 5.28 × 10⁹ M⁻¹ s⁻¹, respectively, whereas those for the HOO˙ radical scavenging in these environments are low with k = 1.27 × 10², 12.1 and 5.48 M⁻¹ s⁻¹, respectively. The radical adduct formation mechanism plays an important role in the reactions of 5-HMF with HO˙ radicals in all of the studied media. [ABSTRACT FROM AUTHOR]