Utility of the Leptospermum scoparium Compound Lepteridine as a Chemical Marker for Mānuka Honey Authenticity

Utility of the Leptospermum scoparium Compound Lepteridine as a Chemical Marker for Mānuka Honey Authenticity

Abstract:

Mānuka honey is a premium food product with unique antimicrobial bioactivity. Concerns with mislabeled mānuka honey require robust assays to determine authenticity. Lepteridine is a Leptospermum-specific fluorescent molecule with potential as an authenticity marker. We describe a mass spectrometry-based assay to measure lepteridine based on an isotopically labeled lepteridine standard. Using this assay, lepteridine concentrations in manuka honey samples strongly correlated with concentrations quantitated by either high-performance liquid chromatography-ultraviolet (HPLC-UV) or fluorescence. A derived minimum lepteridine threshold concentration was compared with the New Zealand regulatory definition for mānuka honey to determine “manuka honey” authenticity on a set of commercial samples. Both methods effectively distinguished mānuka honey from non-mānuka honeys. The regulatory definition excludes lepteridine but otherwise includes the quantification of multiple floral markers together with pollen analysis. Our findings suggest that the quantification of lepteridine alone or in combination with leptosperin could be implemented as an effective screening method to identify mānuka honey, likely to achieve an outcome similar to the regulatory definition.

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