Methylglyoxal May Affect Hydrogen Peroxide Accumulation in Manuka Honey Through the Inhibition of Glucose Oxidase

Abstract Although hydrogen peroxide (H2O2) is one of the major antibacterial factors in most honeys, it does not accumulate in medical-grade manuka honey. The goal of this study was to investigate the effect of artificially added methylglyoxal (MGO) on H2O2 accumulation in natural non-manuka honeys. H2O2 concentrations in the honey solutions were determined using a fluorimetric assay. Two, the most potent H2O2 producers honeydew honeys were mixed with MGO at final concentrations of 250, 500, and 1000 mg/kg, and incubated for 4 days at 37°C. Subsequently, H2O2 concentrations were determined in 50% (wt/vol) MGO supplemented honey solutions. In vitro crosslinking of the enzyme glucose oxidase (GOX) after incubation with MGO was determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Tested honeys at a concentration of 50% (wt/vol) accumulated up to 495.8±9.1 μM H2O2 in 24 h. The most potent producers were the two honeydew honeys, whose 50% solutions accumulated 306.9±6.8 and 495.8±9.1 μM H2O...