New Zealand manuka honey is well-known for its unique antibacterial activity. Due to its high price and limited availability, this honey is often subject to honey fraud. Two pteridine derivatives, 3,6,7-trimethyl-2,4(1H,3H)-pteridinedione and 6,7-dimethyl- 2,4(1H,3H)-pteridinedione, have now been identified in New Zealand manuka honey.
Their structures were elucidated by LC-QTOF-HRMS, NMR, and single-crystal X-ray diffraction after isolation via semi-preparative HPLC. Their marker potential for authentic manuka honey was proved as both substances were neither detectable in the pollen-identical kanuka honey nor in the nine other kinds of monofloral New Zealand honey analyzed (clover, forest, kamahi, pohutukawa, rata, rewarewa, tawari, thyme, and vipers bugloss). The fluorescence property of the pteridine derivatives can be used as an easy and fast TLC screening method for the authentication of genuine manuka honey. 6,7-dimethyl-2,4(1H,3H)-pteridinedione has been describedfor the first time.
This article was published by the Journal of Agriculture and Food Chemistry November 3, 2016.Download Full Article