Action mechanism of naphthofuranquinones against fluconazole-resistant Candida tropicalis strains evidenced by proteomic analysis: The role of increased endogenous ROS.

The increased incidence of candidemia in terciary hospitals worldwide and the cross-resistance frequency require the new therapeutic strategies development. Recently, our research group demonstrated three semi-synthetic naphthofuranquinones (NFQs) with a significant antifungal activity in a fluconazole-resistant (FLC) C. tropicalis strain. The current study aimed to investigate the action's preliminary mechanisms of NFQs by several standardized methods such as proteomic and flow cytometry analyzes, comet assay, immunohistochemistry and confocal microscopy evaluation. Our data showed C. tropicalis 24 h treated with all NFQs induced an expression's increase of proteins involved in the metabolic response to stress, energy metabolism, glycolysis, nucleosome assembly and translation process. Some aspects of proteomic analysis are in consonance with our flow cytometry analysis which indicated an augmentation of intracellular ROS, mitochondrial dysfunction and DNA strand breaks (neutral comet assay and γ-H2AX detection). In conclusion, our data highlights the great contribution of ROS as a key event, probably not the one, associated to anti-candida properties of studied NFQs.

In vitro anti-Candida activity of selective serotonin reuptake inhibitors against fluconazole-resistant strains and their activity against biofilm-forming isolates.

Recent research has shown broad antifungal activity of the classic antidepressants selective serotonin reuptake inhibitors (SSRIs). This fact, combined with the increased cross-resistance frequency of the genre Candida regarding the main treatment today, fluconazole, requires the development of novel therapeutic strategies. In that context, this study aimed to assess the antifungal potential of fluoxetine, sertraline, and paroxetine against fluconazole-resistant Candida spp. planktonic cells, as well as to assess the mechanism of action and the viability of biofilms treated with fluoxetine. After 24 h, the fluconazole-resistant Candida spp. strains showed minimum inhibitory concentration (MIC) in the ranges of 20-160 µg/mL for fluoxetine, 10-20 µg/mL for sertraline, and 10-100.8 µg/mL for paroxetine by the broth microdilution method (M27-A3). According to our data by flow cytometry, each of the SSRIs cause fungal death after damaging the plasma and mitochondrial membrane, which activates apoptotic signaling pathways and leads to dose-dependant cell viability loss. Regarding biofilm-forming isolates, the fluoxetine reduce mature biofilm of all the species tested. Therefore, it is concluded that SSRIs are capable of inhibit the growth in vitro of Candida spp., both in planktonic form, as biofilm, inducing cellular death by apoptosis.

Development and in vitro evaluation of microparticles of fluoxetine in galactomannan against biofilms of S. aureus methicilin resistant.

The emergence of multidrug-resistant (MDR) bacteria is a global problem, by reducing the effectiveness of traditional antibiotics and decreasing the therapeutic arsenal to treat bacterial infections. This has led to an increase in researches about how to overcome this resistance to antibiotics. One strategy is the repositioning (or repurposing) of existing drugs not previously used to combat microorganisms, rather than the development of new drugs. Fluoxetine (FLX) is a selective serotonin reuptake inhibitor (SSRIs) and is considered one of the first highly selective antidepressants of the monoamine neurotransmitter serotonin (5-HT). The objective of this study is to prepare and physically characterize fluoxetine microparticles with galactomannan and evaluate their efficacy against strains of Staphylococcus aureus sensitive and resistant to methicillin. The microparticles were analyzed by differential scanning calorimetry (DSC), infrared analysis (IR) and X-ray diffraction (XRD). In addition, the percentage of encapsulation efficiency (EE%) and drug release kinetics were determined in vitro, along with the determination of the minimum inhibitory concentration (MIC) and evaluation of the action against biofilms. Physical tests were conducted to characterize galactomannan (GAL), FLX, oxacillin (OXA) and the galactomannan/fluoxetine microparticles (GFM). The EE% value was 98 % and, in regard the release, tests with the microparticles released about 60 % of the drug in 200 min. The isolated MIC results for FLX (255 µg/mL) and OXA MIC (1.97-15.62 µg/mL) showed that the strains were resistant. Furthermore, in the biofilms, microparticles showed statically significant improvement for all concentrations used. The study revealed that fluoxetine encapsulated in microparticles has the potential to act as an effective antimicrobial agent.

Mutagenic Evaluation of Fluoxetine and Fluoxetine-Galactomannan Complex Through the Analysis of Chromosomal Aberrations in Human Peripheral Leukocytes and Salmonella typhimurium/Microssome Assay / Avaliação Mutagênica de Fluoxetina e Complexo Fluoxetina-Galactomanana Através da Análise de Aberrações Cromossômicas em Leucócitos Periféricos Humanos e em Salmonella typhimurium / Ensaio Microssômico

Objectives: The purpose of this study was to evaluate the mutagenic potential of fluoxetine and fluoxetine-galactomannan. Methods: Chromosomal aberration test and Salmonella typhimurium/microsome mutagenicity assay. Results: The results showed that fluoxetine (250 µg/mL) can cause chromosomal breaks of treated leukocytes and increase the frequency of reversion of the tester strains of S. typhimurium / microsome assay only at the highest concentration (5 mg/mL), while fluoxetine encapsulated in galactomannan did not cause these changes (leukocytes and S. typhimuriums strains). Conclusion: In summary, fluoxetine showed a mutagenic effect detectable only at high concentrations in both eukaryotic and prokaryotic models. Furthermore, the fluoxetine/galactomannan complex, in this first moment, prevented the mutagenicity attributed to fluoxetine, emphasizing that the present encapsulation process can be an alternative in preventing these effects in vitro.

Objetivos: avaliar o potencial mutagênico da fluoxetina e da fluoxetina-galactomanana. Métodos: Teste de aberração cromossômica e ensaio de mutagenicidade de Salmonella typhimurium /microssoma. Resultados: a fluoxetina (250 µg/mL) pode causar quebras cromossômicas de leucócitos tratados e aumentar a frequência de reversão das cepas testadoras de S. typhimurium /microssoma apenas na concentração mais alta (5 mg/mL), enquanto a fluoxetina encapsulada em galactomanano não causou essas alterações (leucócitos e cepas de S. typhimurium). Conclusão: a fluoxetina mostrou um efeito mutagênico detectável apenas em altas concentrações em modelos eucarióticos e procarióticos. Além disso, o complexo fluoxetina/galactomanan, neste primeiro momento, evitou a mutagenicidade atribuída à fluoxetina, ressaltando que o presente processo de encapsulamento pode ser uma alternativa na prevenção desses efeitos in vitro.