da Silva Cecília Rocha, de Andrade Neto João Batista, de Sousa Campos Rosana, Figueiredo Narjara Silvestre, Sampaio Letícia Serpa, Magalhães Hemerson Iury Ferreira, Cavalcanti Bruno Coêlho, Gaspar Danielle Macêdo, de Andrade Geanne Matos, Lima Iri Sandro Pampolha, de Barros Viana Glauce Socorro, de Moraes Manoel Odorico, Lobo Marina Duarte Pinto, Grangeiro Thalles Barbosa, Nobre Júnior Hélio Vitoriano
Department of Clinical and Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection and Experiments in Yeast (LABEL), Federal University of Ceara, Fortaleza, CE, Brazil.
Antimicrob Agents Chemother. 2014;58(3):1468-78. doi: 10.1128/AAC.00651-13. Epub 2013 Dec 23.
Flavonoids are a class of phenolic compounds commonly found in fruits, vegetables, grains, flowers, tea, and wine. They differ in their chemical structures and characteristics. Such compounds show various biological functions and have antioxidant, antimicrobial, anti-inflammatory, and antiapoptotic properties. The aim of this study was to evaluate the in vitro interactions of flavonoids with fluconazole against Candida tropicalis strains resistant to fluconazole, investigating the mechanism of synergism. Three combinations formed by the flavonoids (+)-catechin hydrated, hydrated quercetin, and (-)-epigallocatechin gallate at a fixed concentration with fluconazole were tested. Flavonoids alone had no antifungal activity within the concentration range tested, but when they were used as a cotreatment with fluconazole, there was significant synergistic activity. From this result, we set out to evaluate the possible mechanisms of cell death involved in this synergism. Isolated flavonoids did not induce morphological changes or changes in membrane integrity in the strains tested, but when they were used as a cotreatment with fluconazole, these changes were quite significant. When evaluating mitochondrial damage and the production of reactive oxygen species (ROS) only in the cotreatment, changes were observed. Flavonoids combined with fluconazole were shown to cause a significant increase in the rate of damage and the frequency of DNA damage in the tested strains. The cotreatment also induced an increase in the externalization of phosphatidylserine, an important marker of early apoptosis. It is concluded that flavonoids, when combined with fluconazole, show activity against strains of C. tropicalis resistant to fluconazole, promoting apoptosis by exposure of phosphatidylserine in the plasma membrane and morphological changes, mitochondrial depolarization, intracellular accumulation of ROS, condensation, and DNA fragmentation.
黄酮类化合物是一类常见于水果、蔬菜、谷物、花朵、茶和葡萄酒中的酚类化合物。它们的化学结构和特性各不相同。这类化合物具有多种生物学功能，具有抗氧化、抗菌、抗炎和抗凋亡特性。本研究的目的是评估黄酮类化合物与氟康唑对耐氟康唑的热带假丝酵母菌菌株的体外相互作用，研究协同作用机制。测试了由固定浓度的黄酮类化合物（+）-儿茶素水合物、水合槲皮素和（-）-表没食子儿茶素没食子酸酯与氟康唑形成的三种组合。在测试浓度范围内，单独的黄酮类化合物没有抗真菌活性，但当它们与氟康唑联合使用时，有显著的协同活性。基于此结果，我们着手评估这种协同作用中涉及的细胞死亡的可能机制。分离出的黄酮类化合物在测试菌株中未诱导形态变化或膜完整性变化，但当它们与氟康唑联合使用时，这些变化非常显著。仅在联合处理中评估线粒体损伤和活性氧（ROS）产生时，观察到了变化。黄酮类化合物与氟康唑联合使用显示出在测试菌株中损伤率和DNA损伤频率显著增加。联合处理还诱导了磷脂酰丝氨酸外化增加，磷脂酰丝氨酸是早期凋亡的重要标志物。结论是，黄酮类化合物与氟康唑联合使用时，对耐氟康唑的热带假丝酵母菌菌株具有活性，通过质膜中磷脂酰丝氨酸的暴露、形态变化、线粒体去极化、细胞内ROS积累、凝聚和DNA片段化促进凋亡。
