Université de Poitiers, UMR CNRS 7267, Laboratoire Ecologie et Biologie des Interactions, Equipe Microbiologie de l'Eau, F-86073 Poitiers, France.
Université de Poitiers, UMR CNRS 7267, Laboratoire Ecologie et Biologie des Interactions, Equipe Microbiologie de l'Eau, F-86073 Poitiers, France.
Int J Antimicrob Agents. 2018 Dec;52(6):947-953. doi: 10.1016/j.ijantimicag.2018.08.020. Epub 2018 Sep 1.
Candida spp., especially Candida albicans, is one of the main colonisers of the oral cavity. Due to its ability to form biofilms, it can be implicated in dental caries, periodontal disease and denture stomatitis. Microbial cells in biofilms are minimally impacted by conventional drugs. The aim of this study was to find new substances able to inhibit the adhesion of Candida spp. in order to prevent biofilm formation in the oral cavity. This study focused on the red raspberry (Rubus idaeus) fruit, known for its richness in potentially antimicrobial tannins. Extraction with a polarity gradient was performed on acetone extracts from frozen ripe and unripe fruits, resulting in eight extracts. The antifungal and anti-adhesion effects of the extracts were determined using broth microdilution and XTT methods, respectively, against C. albicans, Candida glabrata and Candida parapsilosis strains. Interestingly, four extracts (hexane and ethyl acetate) displayed anti-adhesion activity against C. albicans at low concentrations [50% inhibitory concentration (IC) 15.6-62.5 µg/mL]. Bioassay-guided fractionation by chromatographic methods of the most active extract obtained from ripe fruit (ethyl acetate extract) led to two subfractions enriched in anti-adhesion compounds, identified by mass spectrometry analysis as hydrolysable and condensed tannins. Their activities were dose-dependent with maximum inhibition at 80% (IC = 25 µg/mL and 12.5 µg/mL). Regarding antifungal activity, no extract was active against planktonic cells of the tested strains. This work highlights for the first time the potential of raspberries to prevent oral C. albicans biofilms.
念珠菌属（Candida spp.），尤其是白色念珠菌（Candida albicans），是口腔主要定植菌之一。由于其形成生物膜的能力，它可能与龋齿、牙周病和义齿性口炎有关。生物膜中的微生物细胞对常规药物的影响很小。本研究旨在寻找新的物质来抑制念珠菌属的黏附，以防止口腔生物膜的形成。本研究集中在覆盆子（Rubus idaeus）果实上，该果实因富含具有潜在抗菌作用的单宁而闻名。用极性梯度对冷冻成熟和未成熟果实的丙酮提取物进行提取，得到 8 种提取物。分别采用肉汤微量稀释法和 XTT 法测定提取物的抗真菌和抗黏附作用，以白色念珠菌、光滑念珠菌和近平滑念珠菌菌株为研究对象。有趣的是，四种提取物（正己烷和乙酸乙酯）在低浓度下对白色念珠菌表现出抗黏附活性[50%抑制浓度（IC）为 15.6-62.5 µg/mL]。对从成熟果实（乙酸乙酯提取物）获得的最活跃提取物进行基于生物测定的色谱方法的分步分离，得到两种富含抗黏附化合物的亚馏分，通过质谱分析鉴定为可水解和缩合单宁。它们的活性呈剂量依赖性，最大抑制率为 80%（IC=25 µg/mL 和 12.5 µg/mL）。关于抗真菌活性，没有一种提取物对测试菌株的浮游细胞有活性。这项工作首次强调了覆盆子预防口腔白色念珠菌生物膜的潜力。
