Department of Pharmaceutical Engineering, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran, Iran; Department of Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran, Iran.
Department of Biology, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran, Iran.
Int J Pharm. 2024 Feb 15;651:123751. doi: 10.1016/j.ijpharm.2023.123751. Epub 2023 Dec 28.
The use of essential oil (EO) nanoemulsions is expanding to meet customer demand for all-natural antibacterial agents. Thymus daenensis (T) and Mentha piperita (M) EOs were employed to make nanoemulsions (TEO and MEO NE), using Tween 80/Span 80 as surfactant/cosurfactant and a high-speed homogenizer. The TEO and MEO NEs were then characterized in terms of particle size (121, 113 nm), surface charge (-11.2 and -12.6 mV), morphology, and stability over time. Then, the antibacterial activity of EOs and their nanoformulations against Escherichia coli (E. coli) were evaluated based on various residence times, and concentrations on a microfluidic chip. The release of cytoplasmic constituents was used to compare the antibacterial activity of bulk EOs and nanoformulations. After completing MIC, MBC, and time-killing assays, the inhibitory effect of nanoformulations on E. coli biofilm formation was examined. Remarkable intensification was observed by employing a microfluidic chip owing to high-contact surface area provision between nanoemulsions and bacteria. Once compared to the conventional method for 3 h operation, the bacterial activity was nearly completely inhibited in a 24-min residence time using nanoemulsions. After 6 min of treatment, the cell membrane began to rupture, indicating that nanoemulsions could improve the antibacterial activity of bulk essential oils.
纳米乳剂在不断发展以满足消费者对全天然抗菌剂的需求。本研究采用迷迭香（T）和薄荷（M）精油制备纳米乳剂（TEO 和 MEO NE），以吐温 80/司盘 80 为表面活性剂/助表面活性剂，采用高速匀浆法。然后，从粒径（121、113nm）、表面电荷（-11.2 和-12.6mV）、形态和随时间的稳定性等方面对 TEO 和 MEO NEs 进行了表征。然后，基于微流控芯片上不同的停留时间和浓度，评价了精油及其纳米制剂对大肠杆菌（E. coli）的抗菌活性。通过比较细胞质成分的释放来比较精油和纳米制剂的抗菌活性。完成 MIC、MBC 和杀菌时间试验后，考察了纳米制剂对大肠杆菌生物膜形成的抑制作用。采用微流控芯片可显著提高接触面积，从而观察到纳米乳剂的强化效果。与传统方法 3h 操作相比，纳米乳剂在 24min 的停留时间内几乎完全抑制了细菌的活性。处理 6min 后，细胞膜开始破裂，表明纳米乳剂可以提高精油的抗菌活性。
