Sertraline has fungicidal activity against Candida spp. and acts by inhibiting membrane and cell wall biosynthesis.

Aim: Our study evaluated the activity of sertraline (SER) alone and associated with antifungal drugs in planktonic Candida spp. strains, and investigated its mechanism of action. Materials & methods: Broth microdilution method and minimum fungicidal concentration/MIC ratio were used to assess SER anticandidal activity, and the interaction with antifungals was determined by fractional inhibitory concentration index. The mechanism of action was investigated by flow cytometry and in silico tests. Results: SER inhibited Candida spp. strains at low concentrations by the fungicidal effect and showed no loss of effectiveness when combined. Its action seemed to be related to the membrane and cell wall biosynthesis inhibition. Conclusion: SER has activity against Candida spp. isolated and associated with antifungals, and acts by causing cell wall and membrane damage.

Synergistic effect of hydralazine associated with triazoles on Candida spp. in planktonic cells.

Objective: To evaluate the antifungal activity of hydralazine hydrochloride alone and in synergy with azoles against Candida spp. and the action mechanism. Methods: We used broth microdilution assays to determine the MIC, checkerboard assays to investigate synergism, and flow cytometry and molecular docking tests to ascertain action mechanism. Results: Hydralazine alone had antifungal activity in the range of 16-128 µg/ml and synergistic effect with itraconazole versus 100% of the fungal isolates, while there was synergy with fluconazole against 11.11% of the isolates. There was molecular interaction with the receptors exo-B(1,3)-glucanase and CYP51, causing reduced cell viability and DNA damage. Conclusion: Hydralazine is synergistic with itraconazole and triggers cell death of Candida spp. at low concentrations, demonstrating antifungal potential.

Antifungal activity of cisatracurium against fluconazole-resistant Candida isolates and its antibiofilm effects.

Aim: To evaluate the antifungal activity of cisatracurium against Candida spp. resistant to fluconazole strains in planktonic and biofilm forms, in addition to determining its mechanism of action. Materials & methods: Antifungal activity and pharmacological interactions were determined using broth microdilution methods and the mechanism of action was evaluated by flow cytometry and molecular docking. Results: Cisatracurium presented antifungal activity against Candida spp. planktonic cells due to alterations of mitochondrial transmembrane potential leading to cellular apoptosis in addition to interacting with important targets related to cellular respiration, membrane and cell wall evidenced by molecular docking. Furthermore, the drug both prevented biofilm formation and impaired mature biofilms. Conclusion: Cisatracurium exhibits potential antifungal activity against Candida spp.

Antibacterial activity of paroxetine against Staphylococcus aureus and possible mechanisms of action.

Aim: To evaluate the antibacterial activity of paroxetine alone and associated with oxacillin against isolates of methicillin-sensitive and -resistant Staphylococcus aureus. Materials & methods: The broth microdilution and checkerboard techniques were used, with investigation of possible mechanisms of action through flow cytometry, fluorescence microscopy and molecular docking, in addition to scanning electron microscopy for morphological analysis. Results: Paroxetine showed a MIC of 64 µg/ml and bactericidal activity, mostly additive interactions in combination with oxacillin, evidence of action on genetic material and membrane, morphological changes in microbial cells and influence on virulence factors. Conclusion: Paroxetine has antibacterial potential from the perspective of drug repositioning.

Activity of amlodipine against Staphylococcus aureus: association with oxacillin and mechanism of action.

Aim: This study was designed to evaluate the in vitro antimicrobial activity of amlodipine against Staphylococcus aureus strains. Materials & methods: The antimicrobial activity of amlodipine was evaluated by the broth microdilution method and its interaction with oxacillin was evaluated by checkerboard assay. The possible mechanism of action was evaluated by flow cytometry and molecular docking techniques. Results: Amlodipine showed activity against S. aureus between 64 and 128 µg/ml, in addition to showing synergism in approximately 58% of the strains used. Amlodipine also showed good activity against forming and mature biofilms. The possible mechanism of action may be attributed to its ability to lead to cell death. Conclusion: Amlodipine has antibacterial activity against S. aureus.

Activity of arginine-phenylalanine and arginine-tryptophan-based surfactants against Staphylococcus aureus.

Aims: This study aimed to evaluate the antibacterial effect of two new cationic surfactants based on phenylalanine-arginine (LPAM) and tryptophan-arginine (LTAM). Materials & methods: Antibacterial activity, mechanism of action and interactions with Staphylococcus aureus enzymes were measured through microbiological, flow cytometry and molecular docking assays, respectively. Results & conclusion: These compounds showed antibacterial activity in the range of 4.06-16.24 µg/ml against planktonic cells and no activity against mature biofilms, since they caused a loss of membrane integrity and increased DNA damage, as revealed by flow cytometry analysis. In silico assays revealed the existence of molecular bonds such as hydrogen bonds, mainly with DNA. Therefore, these compounds have promising pharmacological activity against MRSA strains.

Antifungal activity of dexamethasone against fluconazole-resistant Candida albicans and its activity against biofilms.

Objective: The present study investigated the antifungal action of dexamethasone disodium phosphate (Dex). Methodology: Susceptibility testing was performed using the Clinical & Laboratory Standards Institute protocol; M27-A3, checkerboard test and biofilm were evaluated with two isolates of Candida albicans, hyphal production test, molecular docking analysis and flow cytometry analysis. Result: Dex and fluconazole (FLC) together had a synergistic effect. Mature biofilm was reduced when treated with Dex alone or in combination. Dex and FLC promoted a decrease in the production of hyphae and changes in the level of mitochondrial depolarization, increased generation of reactive oxygen species, loss of membrane integrity, increased phosphatidylserine externalization and molecular docking; there was interaction with ALS3 and SAP5 targets. Conclusion: Dex showed antifungal activity against FLC-resistant C. albicans strains.

This study aimed to evaluate the antifungal action of dexamethasone against FLC-resistant C. albicans strains.

Synergistic activity of dobutamine combined with azoles and its mechanism of action against strains of Candida glabrata.

Aims: To evaluate the antifungal effect of dobutamine against Candida glabrata as well as its synergism with azoles and its action on biofilm. Methods: The M27-A3 protocol and flow cytometry were used for elucidation of the possible mechanism of action. Results: The tested isolates presented MICs ranging from 2 to 32 µg/ml for dobutamine, with fungistatic effect. A total of 82% of the strains showed synergism with fluconazole, with 90% showing synergism with itraconazole. The effect on biofilm formation was nonsignificant. Cytometry tests showed that dobutamine induced mitochondrial depolarization. Conclusion: Dobutamine has an antifungal effect on strains of C. glabrata and synergistic activity with azoles. This effect is probably mediated by increased oxidative damage to the membrane.

Gallic acid leads to cell death of Candida albicans by the apoptosis mechanism.

Aim: To evaluate the antifungal activity of gallic acid (GA) against the strains of Candida spp. resistant to fluconazole and to determine its mechanism of action. Materials & methods: Antifungal activity was evaluated using the broth microdilution and flow cytometry techniques. Results: GA presented minimum inhibitory concentrations ranging from 16 to 72 µg/ml, causing alterations of the membrane integrity and mitochondrial transmembrane potential, production of reactive oxygen species and externalization of phosphatidylserine. Conclusion: GA has potential antifungal activity against Candida spp.

Synergistic activity of diclofenac sodium with oxacillin against planktonic cells and biofilm of methicillin-resistant Staphylococcus aureus strains.

Aim: To evaluate the activity of diclofenac sodium and synergism with oxacillin against clinical strains of SARM in plactonic cells, antibiofilm and biofilm. Materials & methods: Synergism activity was assessed using the fractional inhibitory concentration index and its possible mechanism of action by flow cytometry. Results: The synergistic activity of diclofenac sodium with oxacillin was observed against plactonic cells, antibiofilm and in biofilm formed from clinical methicillin-resistant Staphylococcus aureus strains. Conclusion: This combination caused damage to the integrity of the membrane and ruptures in the DNA of the cells, leading to apoptosis.

Antifungal activity of ß-lapachone against azole-resistant Candida spp. and its aspects upon biofilm formation.

Aim: The purpose of this study was to assess the antifungal effect of ß-lapachone (ß-lap) on azole-resistant strains of Candida spp. in both planktonic and biofilm form. Materials & methods: The antifungal activity of ß-lap was evaluated by broth microdilution, flow cytometry and the comet assay. The cell viability of the biofilms was assessed using the MTT assay. Results: ß-lap showed antifungal activity against resistant strains of Candida spp. in planktonic form. In addition, ß-lap decreased the viability of mature biofilms and inhibited the formation of biofilms in vitro. Conclusion: ß-lap showed antifungal activity against Candida spp., suggesting that the compound can be utilized as an adjunct agent in the treatment of candidiasis.

Etomidate inhibits the growth of MRSA and exhibits synergism with oxacillin.

Aim: The purpose of this study was to evaluate the antimicrobial activity of the anesthetic etomidate against strains of MRSA and biofilms. Materials & methods: The antibacterial effect of etomidate was assessed by the broth microdilution method. To investigate the probable action mechanism of the compound flow cytometry techniques were used. Results: MRSA strains showed MIC equal to 500 and 1000 µg/ml of etomidate. Four-fifths (80%) of the tested MRSA strains demonstrated synergistic effect with oxacillin. Etomidate also showed activity against MRSA biofilm at concentration of 250 µg/ml. Cytometric analysis revealed that the cells treated with etomidate leading to cell death, probably by apoptosis. Conclusion: Etomidate showed antibacterial activity against MRSA.

Bioactivity and Molecular Docking Studies of Derivatives from Cinnamic and Benzoic Acids.

Over the last decade, there has been a dramatic increase in the prevalence and gravity of systemic fungal diseases. This study aimed therefore at evaluating the antifungal potential of ester derivatives of benzoic and cinnamic acids from three Candida species. The compounds were prepared via Fischer esterification, and the antifungal assay was performed by the microdilution method in 96-well microplates for determining the minimal inhibitory concentrations (MICs). The findings of the antifungal tests revealed that the analogue compound methyl ferulate, methyl o-coumarate, and methyl biphenyl-3-carboxylate displayed an interesting antifungal activity against all Candida strains tested, with MIC values of 31.25-62.5, 62.5-125, and 62.5 µg/ml, respectively. A preliminary Structure-Activity Relationship study of benzoic and cinnamic acid derivatives has led to the recognition of some important structural requirements for antifungal activity. The results of molecular docking indicate that the presence of the enoate moiety along with hydroxyl and one methoxy substitution in the phenyl ring has a positive effect on the bioactivity of compound 7 against Candida albicans. These observations further support the hypothesis that the antifungal activity of compound 7 could be due to its binding to multiple targets, specifically to QR, TS, and ST-PK. Additional experiments are required in the future to test this hypothesis and to propose novel compounds with improved antifungal activity.

Synergistic anticandidal activity of etomidate and azoles against clinical fluconazole-resistant Candida isolates.

Aim: The purpose of this study was to evaluate the effect of etomidate alone and in combination with azoles on resistant strains of Candida spp. in both planktonic cells and biofilms. Materials & methods: The antifungal activity of etomidate was assessed by the broth microdilution test; flow cytometric procedures to measure fungal viability, mitochondrial transmembrane potential, free radical generation and cell death; as well detection of DNA damage using the comet assay. The interaction between etomidate and antifungal drugs (itraconazole and fluconazole) was evaluated by the checkerboard assay. Results: Etomidate showed antifungal activity against resistant strains of Candida spp. in planktonic cells and biofilms. Etomidate also presented synergism with fluconazole and itraconazole in planktonic cells and biofilms. Conclusion: Etomidate showed antifungal activity against Candida spp., indicating that it is a possible therapeutic alternative.

Quinonoid compounds via reactions of lawsone and 2-aminonaphthoquinone with α-bromonitroalkenes and nitroallylic acetates: Structural diversity by C-ring modification and cytotoxic evaluation against cancer cells.

Morita-Baylis-Hillman acetates and α-bromonitroalkenes have been employed in cascade reactions with lawsone and 2-aminonaphthoquinone for the one-pot synthesis of heterocycle fused quinonoid compounds. The reactions reported here utilized the 1,3-binucleophilic potential of hydroxy- and aminonaphthoquinones and the 1,2/1,3-bielectrophilic potential of bromonitroalkenes and Morita-Baylis-Hillman acetates for the synthesis of pyrrole and furan fused naphthoquinones. The synthesized compounds were evaluated against HCT-116 (human colon carcinoma cells), PC3 (human prostate cancer cells), HL-60 (human promyelocytic leukemia cells), SF295 (human glioblastoma cells) and NCI-H460 (human lung cancer cells) and exhibited antitumor activity with IC50 values as low as < 2 µM. Selected compounds were also evaluated against OVCAR-8 (ovary), MX-1 (breast) and JURKAT (leukemia) cell lines. The cytotoxic potential of the quinones evaluated was also assayed using non-tumor cells, exemplified by peripheral blood mononuclear (PBMC) and L929 cells.

On the synthesis of quinone-based BODIPY hybrids: New insights on antitumor activity and mechanism of action in cancer cells.

Fluorescent quinone-based BODIPY hybrids were synthesised and characterised by NMR analysis and mass spectrometry. We measured their cytotoxic activity against cancer and normal cell lines, performed mechanistic studies by lipid peroxidation and determination of reduced (GSH) and oxidized (GSSG) glutathione, and imaged their subcellular localisation by confocal microscopy. Cell imaging experiments indicated that nor-ß-lapachone-based BODIPY derivatives might preferentially localise in the lysosomes of cancer cells. These results assert the potential of hybrid quinone-BODIPY derivatives as promising prototypes in the search of new potent lapachone antitumor drugs.

Synthesis of Selenium-Quinone Hybrid Compounds with Potential Antitumor Activity via Rh-Catalyzed C-H Bond Activation and Click Reactions.

In continuation of our quest for new redox-modulating catalytic antitumor molecules, selenium-containing quinone-based 1,2,3-triazoles were synthesized using rhodium-catalyzed C-H bond activation and click reactions. All compounds were evaluated against five types of cancer cell lines: HL-60 (human promyelocytic leukemia cells), HCT-116 (human colon carcinoma cells), SF295 (human glioblastoma cells), NCIH-460 (human lung cells) and PC3 (human prostate cancer cells). Some compounds showed good activity with IC50 values below 1 µM. The cytotoxic potential of the naphthoquinoidal derivatives was also evaluated in non-tumor cells, exemplified by L929 cells. Overall, these compounds represent promising new lead derivatives and stand for a new class of chalcogenium-containing derivatives with potential antitumor activity.

Encapsulation of nor-ß-lapachone into poly(d,l)-lactide-co-glycolide (PLGA) microcapsules: full characterization, computational details and cytotoxic activity against human cancer cell lines.

In this work, we characterize nor-ß-lapachone-loaded (NßL-loaded) microcapsules prepared using an emulsification/solvent extraction technique. Features such as surface morphology, particle size distribution, zeta potential, optical absorption, Raman and Fourier transform infrared spectra, thermal analysis data, drug encapsulation efficiency, drug release kinetics and in vitro cytotoxicity were studied. Spherical microcapsules with a size of 1.03 ± 0.46 µm were produced with an encapsulation efficiency of approximately 19%. Quantum DFT calculations were also performed to estimate typical interaction energies between a single nor-ß-lapachone molecule and the surface of the microparticles. The NßL-loaded PLGA microcapsules exhibited a pronounced initial burst release. After the in vitro treatment with NßL-loaded microcapsules, a clear phagocytosis of the spheres was observed in a few minutes. The cytotoxic activity against a set of cancer cell lines was investigated.

Novel fluorescent lapachone-based BODIPY: synthesis, computational and electrochemical aspects, and subcellular localisation of a potent antitumour hybrid quinone.

For the first time, a fluorescent lapachone-based BODIPY was synthesised and characterised by NMR and mass spectrometry. Computational and electrochemical aspects, as well as cytotoxic activity and subcellular localisation, were studied. Confocal microscopy experiments indicated that the probe was a specific mitochondria-staining agent. These in-detail analyses were useful in understanding the cytotoxic effects and mechanism of action of this novel hybrid compound. This molecule constitutes a promising prototype owing to its potential biological activities and the new strategies aimed at mechanistic investigations in cells and in vivo, and opens up an interesting avenue of research.

Controlled Release of Nor-ß-lapachone by PLGA Microparticles: A Strategy for Improving Cytotoxicity against Prostate Cancer Cells.

Prostate cancer is one of the most common malignant tumors in males and it has become a major worldwide public health problem. This study characterizes the encapsulation of Nor-ß-lapachone (NßL) in poly(d,l-lactide-co-glycolide) (PLGA) microcapsules and evaluates the cytotoxicity of the resulting drug-loaded system against metastatic prostate cancer cells. The microcapsules presented appropriate morphological features and the presence of drug molecules in the microcapsules was confirmed by different methods. Spherical microcapsules with a size range of 1.03 ± 0.46 µm were produced with an encapsulation efficiency of approximately 19%. Classical molecular dynamics calculations provided an estimate of the typical adsorption energies of NßL on PLGA. Finally, the cytotoxic activity of NßL against PC3M human prostate cancer cells was demonstrated to be significantly enhanced when delivered by PLGA microcapsules in comparison with the free drug.