Free radical production and quenching in honeys with wound healing potential

Objectives: Honey-impregnated wound dressings are now available on drug tariff in the UK, though the modes of action of honeys with antibacterial and wound healing properties are not entirely clear. The action of some but not all of these honeys is linked to the production of hydrogen peroxide on dilution of the honey with wound exudate. The present study investigates both free radical production and the antioxidant potential of some honeys, properties which may have a role to play in wound healing. Methods: Free radical production and quenching of three honey types (manuka, antibacterial but non-peroxide-producing; pasture, antibacterial peroxide-producing; commercial heat processed, non-antibacterial) was investigated by electron paramagnetic resonance (EPR) spectroscopy; quenching was also examined using a superoxide quenching assay. Results: All honeys tested had antioxidant potential, with manuka able to completely quench added radicals within 5 min of spiking. Only the peroxide-producing honey (pasture PS9) was found to form radicals on dilution. Conclusions: The ability to modulate production and quenching of free radicals may contribute to the demonstrated ability of some honeys to help in resolving the state of inflammation typifying chronic wounds.