Isolation, Structural Elucidation, and Synthesis of Lepteridine From Ma̅nuka (Leptospermum scoparium) Honey

Ma̅nuka honey, made from the nectar of Leptospermum scoparium, has garnered scientific and economical interest due to its nonperoxide antibacterial activity. Biomarkers for genuine ma̅nuka honey are increasingly in demand due to the presence of counterfeit ma̅nuka honey. This work reports the identification of a compound previously unreported in ma̅nuka honey by HPLC, and determination of the structure of the as 3,6,7-trimethyllumazine using NMR, MS, IR, and UV/vis spectroscopy. This assignment was confirmed by total synthesis. The natural product, renamed lepteridine, was only observed in ma̅nuka honeys and could potentially serve as a biomarker for genuine ma̅nuka honey.