By Alan Harman, Catch the Buzz
New Zealand’s manuka honey has a new competitor with UK research finding that Scottish heather honey is even more effective as a medicinal treatment.
Keen beekeeper Patrick Pollock, an equine surgeon at the University of Glasgow’s School of Veterinary Medicine, was interested to know if honeys other than manuka might make effective anti-bacterial wound dressings.
Pollock says although manuka has been the most studied honey source to date, he figured other honey sources may have valuable antimicrobial properties as well.
It was a project that fitted in with his work at the university.
“Honey is useful in wound healing, particularly on wounds to the equine limbs,” he says. “There is not much tissue on the lower half of horses’ legs, and wounds can take a long time to heal, or even never fully heal at all.
“Honey helps to promote healing, cleaning the wound and keeping it infection free. If vets were able to use locally-sourced, cheaper honey as a wound dressing, it would be very beneficial particularly in poorer countries.”
Pollock and his team report in The Veterinary Journal they took 29 honey products, including gamma-irradiated and non-irradiated commercial medical grade honeys, supermarket honeys and honeys from local beekeepers.
To exclude contaminated honeys from the project, all honeys were cultured aerobically for evidence of bacterial contamination. Aerobic bacteria or fungi were recovered from 18 products. The antimicrobial activity of the remaining 11 products was assessed against 10 wound bacteria, recovered from the wounds of horses, including methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa.
Eight products were effective against all 10 bacterial isolates at concentrations varying from less than 2% to 16%.
Overall, the Scottish heather honey from the Inverness area was the best performing product and inhibited the growth of all 10 bacterial isolates at concentrations ranging from less than 2% to 6%. It killed MRSA microbes and three other types of bacteria at concentrations of 2%.
“Honeys derived from one type of flower were shown to be the most effective, and while manuka is currently the only medical grade honey, the study reveals that other honeys may be just as suitable for such purposes,” Pollock says.
Consequently, he says, it may prove unnecessary to transport manuka honey from New Zealand when more local sources may be as, or even more, effective.
“In many regions of the world access to expensive antimicrobial drugs is limited, therefore locally sourced honey may provide an inexpensive alternative,” Pollock says.
It may also be possible to identify honeys with activity against specific bacteria.
“This would allow the clinician to select the most appropriate honey type for the infecting organism,” Pollock says.
Honeys largely get their antimicrobial properties from the hydrogen peroxide they contain, but manuka is thought to benefit from other factors, including an as yet poorly understood phytochemical
Honeys largely get their antimicrobial properties from the hydrogen peroxide they contain, but manuka is thought to benefit from other factors, including an as yet poorly understood phytochemical property and, or, the presence of methylglyoxal.
“Some vets use inexpensive honeys intended for human consumption while others use medical grade, gamma-irradiated manuka honey which is sometime incorporated into a wound care product or dressing,” Pollock says. “However, our study suggests that the use of certain non-medical grade honeys, derived from mixed floral sources, may not be appropriate for wound care due to the presence of contaminating aerobic bacteria.”
Pollock tells reporters his findings are exciting for a number of reasons. “Manuka honey is a finite resource and is only available in certain parts of the world, and it’s currently very expensive,” he says. “Here in Glasgow we do a lot of work with working horses, donkeys, and mules in the developing world, and I am particularly hopeful that this research means that we could source local honey types across the globe for use in these hard-working animals which are commonly afflicted with wounds.”