Lichens, due to their symbiotic nature (association between fungi and algae), constitute a chemical factory of original compounds. Polyphenolic compounds (depsides and depsidones) are the main constituents of lichens and are exclusively biosynthesized by these organisms. A panel of 11 polyphenols was evaluated for their anti-biofilm activity against Candida albicans biofilms on the maturation phase (anti-maturation) (MMIC50) as well as on preformed 24-h-old biofilm (anti-biofilm) (MBIC50) using the XTT assay. Minimum inhibitory concentrations of compounds (MICs) against C. albicans planktonic yeast were also determined using a broth microdilution method. While none of the tested compounds were active against planktonic cells (IC50 > 100 µg/ml), three depsides slowed the biofilm maturation (MMIC50 ≤12.5 µg/ml after 48 h of contact with Candida cells). Evernic acid was able to both slow the maturation and reduce the already formed biofilms with MBIC50 ≤12.5 µg/ml after 48 h of contact with the biofilm. This compound shows a weak toxicity against HeLa cells (22%) at the minimal active concentration and no hemolytic activity at 100 µg/ml. Microscopic observations of evernic acid and optimization of its solubility were performed to further study this compound. This work confirmed the anti-biofilm potential of depsides, especially evernic acid, and allows to establish the structure–activity relationships to better explain the anti-biofilm potential of these compounds.
中文翻译:
用于根除白色念珠菌生物膜的地衣多酚化合物
地衣,由于它们的共生性质(真菌和藻类之间的关联),构成了原始化合物的化工厂。多酚化合物(depsides 和 depsidones)是地衣的主要成分,并且完全由这些生物合成。评估了一组 11 种多酚的抗生物膜活性白色念珠菌使用 XTT 测定法检测成熟阶段(抗成熟)(MMIC 50)以及预制 24 小时生物膜(抗生物膜)(MBIC 50)上的生物膜。化合物的最小抑制浓度 (MIC)白色念珠菌还使用肉汤微量稀释法测定浮游酵母。虽然所有测试的化合物都没有对抗浮游细胞的活性(IC 50 > 100 µg/ml),但三种 depsides 减慢了生物膜的成熟(MMIC 50 ≤12.5 µg/ml 在与浮游细胞接触 48 小时后念珠菌细胞)。在与生物膜接触 48 小时后,依维尼克酸能够减缓成熟并减少已经形成的生物膜,MBIC 50 ≤12.5 µg/ml。该化合物在最低活性浓度下对 HeLa 细胞显示出微弱的毒性 (22%),在 100 µg/ml 时没有溶血活性。进行了衣藻酸的显微观察及其溶解度的优化以进一步研究该化合物。这项工作证实了 depsides,尤其是常春藤酸的抗生物膜潜力,并允许建立结构-活性关系,以更好地解释这些化合物的抗生物膜潜力。