Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo, 11884, Egypt.
Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo, 11884, Egypt.
Microb Pathog. 2024 Jul;192:106705. doi: 10.1016/j.micpath.2024.106705. Epub 2024 May 17.
This study aimed to investigate the potential of cinnamon oil nanoemulsion (CONE) as an antibacterial agent against clinical strains of colistin-resistant Klebsiella pneumoniae and its anticancer activity. The prepared and characterized CONE was found to have a spherical shape with an average size of 70.6 ± 28.3 nm under TEM and a PDI value of 0.076 and zeta potential value of 6.9 mV using DLS analysis. The antibacterial activity of CONE against Klebsiella pneumoniae strains was investigated, and it was found to have higher inhibitory activity (18.3 ± 1.2-30.3 ± 0.8 mm) against the tested bacteria compared to bulk cinnamon oil (14.6 ± 0.88-20.6 ± 1.2) with MIC values ranging from 0.077 to 0.31 % v/v which equivalent to 0.2-0.82 ng/ml of CONE. CONE inhibited the growth of bacteria in a dose and time-dependent manner based on the time-kill assay in which Klebsiella pneumoniae B-9 was used as a model among the bacterial strains under investigation. The study also investigated the expression of the mcr-1 gene in the Klebsiella pneumoniae strains and found that all strains were positive for the gene expression and subsequently its presence. The level of mcr-1 gene expression among the B-2, B-4, B-9, and B-11 control strains and that treated with colistin was similar, but it was different in both B-5 and B-2. However, all strains exhibited a significant downregulation in gene expression (ranging from 3.97 to 8.7-fold) after their treatment with CONE. Additionally, the CONE-treated bacterial cells appeared with a great deformation compared with control cells under TEM. Finally, CONE exhibited selective toxicity against different cancer cell lines depending on comparison with the normal cell lines.
本研究旨在探讨肉桂油纳米乳液（CONE）作为一种抗粘菌素耐药肺炎克雷伯氏菌的抗菌剂的潜力及其抗癌活性。所制备和表征的 CONE 在 TEM 下呈球形，平均粒径为 70.6 ± 28.3nm，PDI 值为 0.076，Zeta 电位值为 6.9mV，使用 DLS 分析。研究了 CONE 对肺炎克雷伯氏菌菌株的抗菌活性，发现其对测试细菌的抑制活性更高（18.3 ± 1.2-30.3 ± 0.8mm），与肉桂油（14.6 ± 0.88-20.6 ± 1.2）相比，MIC 值范围为 0.077-0.31%v/v，相当于 CONE 的 0.2-0.82ng/ml。CONE 以剂量和时间依赖的方式抑制细菌的生长，基于时间杀伤试验，其中 B-9 肺炎克雷伯氏菌被用作研究细菌中的模型。该研究还研究了 mcr-1 基因在肺炎克雷伯氏菌菌株中的表达，发现所有菌株均为 mcr-1 基因阳性表达，随后均为阳性。B-2、B-4、B-9 和 B-11 对照菌株和用粘菌素处理的菌株的 mcr-1 基因表达水平相似，但 B-5 和 B-2 不同。然而，所有菌株在 CONE 处理后，基因表达均显著下调（3.97-8.7 倍）。此外，与对照细胞相比，CONE 处理后的细菌细胞在 TEM 下出现明显的变形。最后，CONE 对不同的癌细胞系表现出选择性毒性，与正常细胞系相比。
