Lin Bin, Daniels Benjamin J, Middleditch Martin J, Furkert Daniel P, Brimble Margaret A, Bong Jessie, Stephens Jonathan M, Loomes Kerry M
School of Biological Sciences and Institute for Innovation in Biotechnology, The University of Auckland, Auckland PB92019, New Zealand.
School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand.
ACS Omega. 2020 Apr 8;5(15):8858-8866. doi: 10.1021/acsomega.0c00486. eCollection 2020 Apr 21.
Manuka honey is a premium food product with unique antimicrobial bioactivity. Concerns with mislabeled manuka honey require robust assays to determine authenticity. Lepteridine is a -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 manuka honey to determine "manuka honey" authenticity on a set of commercial samples. Both methods effectively distinguished manuka honey from non-manuka 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 manuka honey, likely to achieve an outcome similar to the regulatory definition.
麦卢卡蜂蜜是一种具有独特抗菌生物活性的优质食品。对麦卢卡蜂蜜标签错误的担忧需要可靠的检测方法来确定其真伪。勒普蝶啶是一种特异性荧光分子，有潜力作为真伪标记物。我们描述了一种基于质谱的检测方法，用于基于同位素标记的勒普蝶啶标准品来测量勒普蝶啶。使用该检测方法，麦卢卡蜂蜜样品中的勒普蝶啶浓度与通过高效液相色谱 - 紫外（HPLC - UV）或荧光法定量的浓度密切相关。将推导得出的最低勒普蝶啶阈值浓度与新西兰对麦卢卡蜂蜜的监管定义进行比较，以确定一组商业样品中“麦卢卡蜂蜜”的真伪。两种方法都能有效区分麦卢卡蜂蜜和非麦卢卡蜂蜜。监管定义不包括勒普蝶啶，但除此之外还包括多种花卉标记物的定量分析以及花粉分析。我们的研究结果表明，单独定量勒普蝶啶或与异槲皮苷联合使用，可以作为一种有效的筛选方法来鉴定麦卢卡蜂蜜，可能会得到与监管定义类似的结果。
