Tuesday, July 07, 2015

Not All Species of Leptospermum Produce Active Honey

The Quantitation of Dihydroxyacetone in Australian Nectar via High Performance Liquid Chromatography

J Agric Food Chem. 2015 Jul 3

The non-peroxide antibacterial activity of New Zealand mānuka honey originates from dihydroxyacetone (DHA) within Leptospermum scoparium nectar.

This study determined if DHA was present within the nectar of four Australian Leptospermum species: L. laevigatum, L. polygalifolium, L. trinervium and L. whitei. A rapid and convenient new method was developed, which quantitated DHA:sugar ratios (ppm). The DHA and sugars were derivatised with o-(2, 3, 4, 5, 6-pentafluorobenzyl) hydroxylamine hydrochloride and analyzed via RP-HPLC with diode array detection at two wavelengths (200 nm and 243 nm). DHA was detected in all L. whitei and L. polygalifolium samples, where DHA:sugar ratios ranged from 10169-24199 ppm and 9321-20174 ppm, respectively. DHA was undetected in any of the L. laevigatum and L. trinervium samples, and nectar activity was less than 100 ppm.

The results of this study have implications for the Australian beekeeping industry, as the findings indicated that not all species of Leptospermum will produce active honey.

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