Oral Ecology Research Group, Faculty of Dentistry, Université Laval, 2420 Rue de la Terrasse, Quebec City, QC, G1V 0A6, Canada.
BMC Complement Altern Med. 2019 Nov 8;19(1):303. doi: 10.1186/s12906-019-2730-2.
Candida albicans is an opportunistic pathogen that causes oral candidiasis and denture stomatitis. It has also been reported to infect oral mucositis lesions in patients who suffer from cancer affecting the head and neck and who receive chemotherapy and radiotherapy treatments. This study aimed to investigate the effects of two cinnamon bark fractions, i.e., an essential oil and an aqueous extract enriched in proanthocyanidins (Cinnulin PF®) on growth, biofilm formation, and adherence properties of C. albicans as well as on oral epithelial cells (barrier integrity, inflammatory response).
A microplate dilution assay was used to determine antifungal and anti-biofilm properties. A fluorescent assay was used to determine C. albicans adherence to oral epithelial cells. Cytotoxicity toward oral epithelial cells was assessed by determination of cell metabolic activity. Tight junction integrity of gingival keratinocytes was assessed by determination of transepithelial electrical resistance. IL-6 and IL-8 secretion by TNFα-stimulated oral epithelial cells was quantified by ELISA.
While Cinnulin PF® did not reduce C. albicans growth, the cinnamon bark oil exhibited high antifungal activity with minimum inhibitory concentrations and minimum fungicidal concentrations in the range of 0.039 to 0.078%. The cinnamon oil was also active against a pre-formed C. albicans biofilm. Interestingly, Cinnulin PF® prevented biofilm formation by C. albicans and attenuated its adherence to oral epithelial cells. At their effective concentrations, the cinnamon oil and the Cinnulin PF® displayed no significant cytotoxicity against oral epithelial cells. In an in vitro model, both cinnamon fractions reinforced the integrity of the oral epithelial barrier. Lastly, Cinnulin PF® inhibited the secretion of interleukin-6 and interleukin-8 by oral epithelial cells stimulated with TNF-α.
By their ability to attenuate growth, biofilm formation and adherence property of C. albicans, to reinforce the epithelial barrier function, and to exert anti-inflammatory properties the two cinnamon fractions (essential oil, Cinnulin PF®) investigated in the present study may be promising agents for treating oral infections involving C. albicans.
白色念珠菌是一种机会致病菌，可引起口腔念珠菌病和义齿性口炎。据报道，它还会感染头颈部癌症患者接受化疗和放疗治疗后出现的口腔黏膜炎病变。本研究旨在探讨两种肉桂树皮提取物，即精油和富含原花青素的水提取物（Cinnulin PF®）对白色念珠菌生长、生物膜形成和黏附特性以及口腔上皮细胞（屏障完整性、炎症反应）的影响。
采用微量稀释法测定抗真菌和抗生物膜特性。采用荧光法测定白色念珠菌对口腔上皮细胞的黏附。通过测定细胞代谢活性来评估对口腔上皮细胞的细胞毒性。通过测定跨上皮电阻来评估牙龈角质形成细胞的紧密连接完整性。通过 ELISA 定量测定 TNFα 刺激的口腔上皮细胞中 IL-6 和 IL-8 的分泌。
虽然 Cinnulin PF® 不会减少白色念珠菌的生长，但肉桂树皮油表现出很高的抗真菌活性，最小抑菌浓度和最小杀菌浓度在 0.039 至 0.078%范围内。肉桂油对已形成的白色念珠菌生物膜也具有活性。有趣的是，Cinnulin PF® 可防止白色念珠菌生物膜的形成并减弱其对口腔上皮细胞的黏附。在有效浓度下，肉桂油和 Cinnulin PF® 对口腔上皮细胞均无明显的细胞毒性。在体外模型中，两种肉桂类化合物均增强了口腔上皮屏障的完整性。最后，Cinnulin PF® 抑制了 TNF-α 刺激的口腔上皮细胞中白细胞介素-6 和白细胞介素-8 的分泌。
通过减弱白色念珠菌的生长、生物膜形成和黏附特性、增强上皮屏障功能以及发挥抗炎特性，本研究中研究的两种肉桂类化合物（精油、Cinnulin PF®）可能是治疗涉及白色念珠菌的口腔感染的有前途的药物。
