Antibacterial honey linked to mānuka trees
24 Apr, 2009
Source: Manuka Health NZ
Scientists have discovered a compound in New Zealand mānuka tree nectar that converts to the honey’s antibacterial constituent.
It has been known for some time that the unique antibacterial activity of mānuka honey is associated with methylglyoxal, but the origin of the compound was unclear, Waikato University Associate Professor Merilyn Manley-Harris says.
Researchers in the University of Waikato’s Chemistry Department found dihydroxyacetone (DHA) is present in mānuka honey shortly after bees deposit it in the comb. As the honey ripens, the DHA converts to methylglyoxal.
During the study, young mānuka honey was stored for 120 days and showed a strong correlation in the drop-off of DHA and the increase in methylglyoxal over that time.
Because DHA is not antibacterial like methylglyoxal, the antibacterial activity increases as the honey matures, the scientists explain.
Dr Manley-Harris says once researchers realised the DHA was the precursor to methylglyoxal, they set about finding out where the DHA came from. They discovered it when they tested the nectar in mānuka flowers from various trees around Hamilton and the Waikato.
By testing the nectar of the mānuka flowers, it was possible to identify which trees would produce highly active mānuka honey when harvested by bees. Those trees could then be bred and planted as a high value crop on marginal land.
Mānuka ( Leptospermum scoparium) is fast-growing and is tolerant of poor soils, exposure and waterlogged sites. It is commonly called tea tree because early settlers reputedly used the leaves as a substitute for tea from China.
