RESUMEN
Introduction. Candida spp. are commensal fungal pathogens of humans, but when there is an imbalance in the microbiota, or weak host immunity, these yeasts can become pathogenic, generating high medical costs.Gap Statement. With the increase in resistance to conventional antifungals, the development of new therapeutic strategies is necessary. This study evaluated the in vitro antifungal activity of chlorogenic acid against fluconazole-resistant strains of Candida spp. Mechanism of action through flow cytometry and in silico analyses, as well as molecular docking assays with ALS3 and SAP5, important proteins in the pathogenesis of Candida albicans associated with the adhesion process and biofilm formation.Results. The chlorogenic acid showed in vitro antifungal activity against the strains tested, causing reduced cell viability, increased potential for mitochondrial depolarization and production of reactive oxygen species, DNA fragmentation and phosphatidylserine externalization, indicating an apoptotic process. Concerning the analysis through docking, the complexes formed between chlorogenic acid and the targets Thymidylate Kinase, CYP51, 1Yeast Cytochrome BC1 Complex e Exo-B-(1,3)-glucanase demonstrated more favourable binding energy. In addition, chlorogenic acid presented significant interactions with the ALS3 active site residues of C. albicans, important in the adhesion process and resistance to fluconazole. Regarding molecular docking with SAP5, no significant interactions were found between chlorogenic acid and the active site of the enzyme.Conclusion. We concluded that chlorogenic acid has potential use as an adjuvant in antifungal therapies, due to its anti-Candida activity and ability to interact with important drug targets.
Asunto(s)
Antifúngicos , Fluconazol , Antifúngicos/farmacología , Apoptosis , Biopelículas , Candida , Candida albicans , Ácido Clorogénico/farmacología , Farmacorresistencia Fúngica , Fluconazol/farmacología , Humanos , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento MolecularRESUMEN
The emergence of Candida spp. with resistance to antifungal molecules, mainly the azole class, is an increasing complication in hospitals around the globe. Aim: In the present research, we evaluated the synergistic effects of ketamine with two azole derivatives, itraconazole and fluconazole, on strains of Candida spp. to fluconazole. Materials & methods: The drug synergy was evaluated by quantifying the fractional inhibitory concentration index and by fluorescence microscopy and flow cytometry techniques. Results: Our achievements showed a synergistic effect between ketamine in addition to the two antifungal agents (fluconazole and itraconazole) against planktonic cells and biofilms of Candida spp. Conclusion: This combination promoted alteration of membrane integrity, generation of reactive oxygen species, damage to and DNA and externalization of phosphatidylserine.
Asunto(s)
Antifúngicos/farmacología , Candida/efectos de los fármacos , Fluconazol/farmacología , Itraconazol/farmacología , Ketamina/farmacología , Animales , Biopelículas/efectos de los fármacos , Candida/fisiología , Candida albicans/efectos de los fármacos , Candida albicans/fisiología , Supervivencia Celular/efectos de los fármacos , Daño del ADN , Fragmentación del ADN , ADN de Hongos/efectos de los fármacos , Farmacorresistencia Fúngica , Sinergismo Farmacológico , Células L , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana , Fosfatidilserinas/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Emergence of methicilin resistant Staphylococcus aureus (MRSA) strains is a major cause of infirmity worldwide and has limited our therapeutic options against these pathogens. In this regard, the search for candidates with an antimicrobial activity, with a greater efficacy and a lower toxicity, is necessary. As a result, there is greater need to search for resistance modifying agents which, in combination with existing drugs, will restore the efficacy of these drugs. The antibacterial effect of fluoxetine was determined by a broth microdilution method (the M07-A9 method of the Clinical and Laboratory Standard Institute) and flow cytometry techniques in which the probable mechanism of action of the compound was also assessed. The isolates used in the study belonged to the Laboratory of Bioprospecting of Antimicrobial Molecules (LABIMAN) of the Federal University of Ceará. After 24â¯h, Methicillin-resistant Sthaphylococcus aureus (MRSA) strains showed fluoxetine MICs equal to 64⯵g/mL and 128⯵g/mL, respectively. Cytometric analysis showed that treatment with fluoxetine caused alterations to the integrity of the plasma membranes and DNA damage, which led to cell death, probably by apoptosis.
Asunto(s)
Antibacterianos/farmacología , Fluoxetina/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Daño del ADN , Citometría de Flujo , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacosRESUMEN
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.