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.

中文翻译：

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的效果锡兰肉桂叶精油上的毒力因子念珠菌物种和测定的被检体内与毒性蜡螟模型

背景技术从肉桂（Cinnamomum verum）提取的精油（EO）已经用作抗微生物剂已有数百年历史了。C. verum叶油对微生物毒性的影响尚未得到很好的研究。目的本研究评估了真叶念珠菌叶油对白色念珠菌，热带念珠菌和dubliniensis的三种毒力因子的作用及其体内毒性。方法采用气相色谱-质谱法（GC-MS）测定EO的化学成分。使用临床和实验室标准协会（CLSI）M27-A3肉汤微量稀释法确定最低抑菌浓度（MIC）。在使念珠菌细胞粘附于聚苯乙烯表面2小时后，使用XTT测定法量化了EO对初始粘附的影响。使用XTT生存力测定法定量分析在EO存在下念珠菌的生物膜形成。使用标准方案评估减少生殖管形成的功效。分别使用扫描电子显微镜（SEM）和延时摄影显微镜观察EO处理下生物膜的形成和进展。用半空果幼虫测定EO的体内毒性。氯己定二葡萄糖酸酯：阳性对照。结果丁香酚是EO的主要成分。MIC为1.0mg / mL。白色念珠菌，热带念珠菌和杜比尼梭菌的初始粘附力分别降低了50％，分别为1.0，> 2.0和0.34 mg / mL。0.5和1.0 mg / mL可显着抑制胚芽管的形成。用于形成生物膜的MBIC50≤0.35 mg / mL。1.0 mg / mL可防止念珠菌的生物膜进展。SEM图像显示细胞壁损伤，细胞收缩和减少的菌丝形成。在任何测试浓度下的体内实验模型均未观察到致死作用。结论C. verum叶油可对抗念珠菌的致病因子，且无任何毒性。