Manuka oil, an essential oil derived from the Leptospermum scoparium, has been traditionally used for wound care and as a topical antibacterial, antifungal, and anti-inflammatory. However, the essential oil is not well retained at mucosal sites, such as the oral cavity, where the benefits of the aforementioned properties could be utilized toward the treatment of persistent biofilms. Within this study, L. scoparium essential oil was incorporated into a semisolid emulsion for improved delivery. The safety profile of L. scoparium essential oil on human gingival fibroblasts was determined via cell viability, cytotoxicity, and caspase activation. The minimal bactericidal concentration of L. scoparium essential oil was determined, and the emulsion's antibiofilm effects visualized using confocal laser scanning microscopy. L. scoparium essential oil demonstrated a lower IC50 (0.02% at 48 h) when compared to the clinical control chlorhexidine (0.002% at 48 h) and displayed lower cumulative cytotoxicity. Higher concentrations of L. scoparium essential oil (≥ 0.1%) at 6 h resulted in higher caspase 3/7 activation, suggesting an apoptotic pathway of cell death. A minimal bactericidal concentration of 0.1% w/w was observed for 6 oral bacteria and 0.01% w/v for Porphyromonas gingivalis. Textural and rheometric analysis indicated increased stability of emulsion with a 1 : 3 ratio of L. scoparium essential oil: Oryza sativa carrier oil. The optimized 5% w/w L. scoparium essential oil emulsion showed increased bactericidal penetrative effects on Streptococci gordonii biofilms compared to oil alone and to chlorhexidine controls. This study has demonstrated the safety, formulation, and antimicrobial activity of L. scoparium essential oil emulsion for potential antibacterial applications at mucosal sites.

中文翻译：

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一种含有 Leptospermum scoparium 精油的半固体乳液的配方和体外抗菌和抗生物膜功效的评价

麦卢卡油是一种从 Leptospermum scoparium 中提取的精油，传统上用于伤口护理和局部抗菌、抗真菌和抗炎。然而，精油不能很好地保留在粘膜部位，例如口腔，在那里可以利用上述特性的好处来治疗持久性生物膜。在这项研究中，将 L. scoparium 精油加入半固体乳液中以改善递送。L. scoparium 精油对人牙龈成纤维细胞的安全性是通过细胞活力、细胞毒性和半胱天冬酶激活来确定的。确定了 L. scoparium 精油的最小杀菌浓度，并使用共聚焦激光扫描显微镜观察乳液的抗生物膜效应。L。与临床对照氯己定（48 小时时为 0.002%）相比，scoparium 精油显示出更低的 IC50（48 小时时为 0.02%），并且显示出更低的累积细胞毒性。6 小时时更高浓度的 L. scoparium 精油（≥ 0.1%）导致更高的 caspase 3/7 活化，表明细胞死亡的凋亡途径。观察到 6 种口腔细菌的最低杀菌浓度为 0.1% w/w，牙龈卟啉单胞菌的最低杀菌浓度为 0.01% w/v。质地和流变分析表明，当 L. scoparium 精油：Oryza sativa 载体油的比例为 1:3 时，乳液的稳定性增加。与单独的油和氯己定对照相比，优化的 5% w/w L. scoparium 精油乳液对 Streptococci gordonii 生物膜显示出更高的杀菌渗透作用。这项研究证明了安全性，