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

Manuka honey, made from the nectar of Leptospermum scoparium, has garnered scientific and economical interest due to its nonperoxide antibacterial activity. Biomarkers for genuine manuka honey are increasingly in demand due to the presence of counterfeit manuka honey. This work reports the identification of a compound previously unreported in manuka 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 manuka honeys and could potentially serve as a biomarker for genuine manuka honey.