School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia.
School of Chemistry, University of Sydney, Sydney, New South Wales, Australia.
PLoS One. 2024 May 22;19(5):e0303095. doi: 10.1371/journal.pone.0303095. eCollection 2024.
The growing burden of expired medicines contributes to environmental contamination and landfill waste accumulation. Medicinal honey, with its non-toxic nature and potentially long shelf-life, represents a promising and underutilised therapeutic that avoids some of these issues. However, limited knowledge on how its antimicrobial properties change over time combined with a lack of reliable processes in the honey industry for measuring antimicrobial potential, hinder its clinical adoption. Using a diverse selection of 30 Australian honey samples collected between 2005 and 2007, we comprehensively evaluated their antibacterial and antifungal activity and pertinent physical and chemical properties with the aims of assessing the effect of long-term storage on activity, pinpointing factors associated with antimicrobial efficacy, and establishing robust assessment methods. Minimum inhibitory concentration (MIC) assays proved superior to the standard phenol equivalence assay in capturing the full range of antimicrobial activity present in honey. Correlations between activity and a range of physical and chemical properties uncovered significant associations, with hydrogen peroxide, antioxidant content, and water activity emerging as key indicators in non-Leptospermum honey. However, the complex nature and the diverse composition of honey samples precludes the use of high-throughput chemical tests for accurately assessing this activity, and direct assessment using live microorganisms remains the most economical and reliable method. We provide recommendations for different methods of assaying various honey properties, taking into account their accuracy along with technical difficulty and safety considerations. All Leptospermum and fourteen of seventeen non-Leptospermum honey samples retained at least some antimicrobial properties after 15-17 years of storage, suggesting that honey can remain active for extended periods. Overall, the results of this study will help industry meet the growing demand for high-quality, medicinally active honey while ensuring accurate assessment of its antimicrobial potential.
过期药品的负担日益加重，导致环境污染和垃圾填埋场废物堆积。药用蜂蜜具有无毒性质和潜在的长保质期，是一种有前途但未得到充分利用的治疗方法，可以避免这些问题。然而，由于对其抗菌特性随时间变化的了解有限，以及蜂蜜行业缺乏可靠的测量抗菌潜力的方法，限制了其临床应用。我们使用 2005 年至 2007 年间收集的 30 种澳大利亚蜂蜜样本进行了广泛评估，以全面评估其抗菌和抗真菌活性以及相关的物理和化学特性，目的是评估长期储存对活性的影响，确定与抗菌功效相关的因素，并建立可靠的评估方法。最小抑菌浓度 (MIC) 测定法优于标准苯酚等效测定法，可捕获蜂蜜中存在的全部抗菌活性。活性与一系列物理和化学特性之间的相关性揭示了显著的相关性，其中过氧化氢、抗氧化剂含量和水活度是非 Leptospermum 蜂蜜中的关键指标。然而，蜂蜜样本的复杂性质和多样化组成使得无法使用高通量化学测试来准确评估这种活性，并且使用活微生物进行直接评估仍然是最经济和可靠的方法。我们根据不同的蜂蜜特性提出了不同的测试方法建议，同时考虑了它们的准确性、技术难度和安全因素。所有 Leptospermum 和 17 种非 Leptospermum 蜂蜜样本中的 14 种在储存 15-17 年后保留了至少部分抗菌特性，这表明蜂蜜可以保持较长时间的活性。总的来说，这项研究的结果将有助于满足对高质量、药用活性蜂蜜的日益增长的需求，同时确保对其抗菌潜力进行准确评估。
