Use of kinetic data to model potential antioxidant activity: Radical scavenging capacity of Australian Eucalyptus honeys

Abstract

Antioxidant activity of honeys may be beneficial in wound healing processes by protecting cells against lipid oxidation. The DPPH assay assesses the efficacy of antioxidant molecules to reduce DPPH• to DPPHH. Studies determining EC50 are limited by single time-point determinations of antioxidant effect and can miss vital information about the rate of antioxidant response. Acquisition of kinetic data allows determination of the radical scavenging capacity (RSC) of honeys. The purpose of this study was to determine the RSC of 53 honeys from 16 species of Australian Eucalyptus trees and four samples of New Zealand manuka (Leptospermum scoparium) honey. Whereas honeys could not be differentiated based on EC50 values, significant differences were observed for RSC, supporting collection of kinetic data for honey analysis. The greatest RSC was observed for New Zealand manuka (4.6 ± 0.3 × 10−5 mg.mL−1.min−1), grey ironbark (E. paniculate; 3.4 ± 0.2 × 10−5 mg.mL−1.min−1) and river red gum honeys (E. camaldulensis; 3.2 ± 0.2 × 10−5 mg.mL−1.min−1).