肉桂叶精油对念珠菌属物种毒力因子的影响及利用大蜡螟模型测定其体内毒性。
Effect of Cinnamomum verum leaf essential oil on virulence factors of Candida species and determination of the in-vivo toxicity with Galleria mellonella model.
机构信息
Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba, Área de Microbiologia e Imunologia, Departamento de Diagnóstico Oral, Campinas SP, Brasil.
Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba, Área de Farmacologia, Anestesiologia e Terapêutica, Departamento de Ciências Fisiológicas, Campinas, SP, Brasil.
出版信息
Mem Inst Oswaldo Cruz. 2020 Sep 25;115:e200349. doi: 10.1590/0074-02760200349. eCollection 2020.
BACKGROUND
Essential oils (EO) extracted from Cinnamomum verum has been used as an antimicrobial agents for centuries. The effects of C. verum leaf oil against virulence of microorganisms is not well studied yet.
OBJECTIVES
This study evaluates the effect of C. verum leaf oil against three virulence factors of Candida albicans, C. tropicalis and C. dubliniensis and its in-vivo toxicity.
METHODS
Chemical composition of EO was determined using gas chromatography-mass spectrometry (GC-MS). Minimum inhibitory concentration (MIC) was determined using clinical and laboratory standards institute (CLSI) M27-A3 broth microdilution. Effect of EO on initial adhesion was quantified using XTT assay after allowing Candida cells to adhere to the polystyrene surface for 2 h. Biofilm formation of Candida in the presence of EO was quantified using XTT viability assay. Efficacy on reduction of germ tube formation was evaluated using standard protocol. Visualisation of biofilm formation and progression under the EO treatment were done using scanning electron microscope (SEM) and Time lapses microscope respectively. In-vivo toxicity of EO was determined using Galleria mellonella larvae. Chlorhexidine digluconate: positive control.
RESULTS
Eugenol was the main compound of EO. MIC was 1.0 mg/mL. 50% reduction in initial adhesion was achieved by C. albicans, C. tropicalis and C. dubliniensis with 1.0, > 2.0 and 0.34 mg/mL respectively. 0.5 and 1.0 mg/mL significantly inhibit the germ tube formation. MBIC50 for forming biofilms were ≤ 0.35 mg/mL. 1.0 mg/mL prevent biofilm progression of Candida. SEM images exhibited cell wall damages, cellular shrinkages and decreased hyphal formation. No lethal effect was noted with in-vivo experiment model at any concentration tested.
CONCLUSION
C. verum leaf oil acts against virulence factors of Candida and does not show any toxicity.
背景
肉桂叶精油（Cinnamomum verum）作为一种抗菌剂已有数百年的历史。然而，肉桂叶油对微生物毒力的影响尚未得到充分研究。
目的
本研究评估肉桂叶油对白色念珠菌、热带念珠菌和都柏林念珠菌三种毒力因子的作用及其体内毒性。
方法
采用气相色谱-质谱联用仪（GC-MS）测定精油的化学成分。采用临床和实验室标准协会（CLSI）M27-A3 肉汤微量稀释法测定最小抑菌浓度（MIC）。采用 XTT 法测定精油对初始黏附的影响，使念珠菌细胞黏附于聚苯乙烯表面 2 h 后定量。采用 XTT 活力测定法测定有精油存在时念珠菌生物膜的形成。采用标准方案评估减少芽管形成的效果。通过扫描电子显微镜（SEM）和时差显微镜分别观察精油处理下生物膜的形成和进展。采用大蜡螟幼虫测定精油的体内毒性。洗必泰葡萄糖酸盐：阳性对照。
结果
丁香酚是精油的主要成分。MIC 为 1.0 mg/mL。C. albicans、C. tropicalis 和 C. dubliniensis 的初始黏附减少 50%所需的浓度分别为 1.0、>2.0 和 0.34 mg/mL。0.5 和 1.0 mg/mL 可显著抑制芽管形成。形成生物膜的 MBIC50 值均≤0.35 mg/mL。1.0 mg/mL 可阻止念珠菌生物膜的进展。SEM 图像显示细胞壁损伤、细胞收缩和菌丝形成减少。在任何测试浓度下，体内实验模型均未观察到致死作用。
结论
肉桂叶油可作用于念珠菌的毒力因子，且无任何毒性。
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