RESUMO
Aim: Polymyxin B (PMB) is one of the few therapeutic options for treating infections caused by carbapenem-resistant Gram-negative bacteria (CR-GNB). However, the emergence of PMB-resistant CR-GNB strains has prompted the exploration of antibiotic adjuvants as potential therapeutic avenues. Thus, this study evaluates the potential of 3,5-dinitrobenzoic acid derivatives (DNH01, DNH11, DNH13 and DNH20) and isoniazid-N-acylhydrazones (INZ1-7, INZ9 and INZ11) as adjuvants to enhance PMB efficacy against CR-GNB.Materials & methods: MIC, MBC and drug combination assays were conducted using multidrug-resistant clinical isolates of Enterobacterales and Acinetobacter baumannii. In addition, the effects of PMB and PMB + DNH derivatives were assessed through flow cytometry and scanning electron microscopy (SEM).Results: DNH01, DNH11 and DNH20, unlike the INH-acylhydrazones, significantly restored PMB activity (MIC ≤ 2 µg/ml) in 80% of the tested isolates. Flow cytometry and SEM assays confirmed that DNH derivatives rescued the activity of PMB, yielding results comparable to those expected for PMB alone but at 256-fold lower concentrations.Conclusion: These findings suggest DNH derivatives hold substantial promise as PMB adjuvants to combat PMB-resistant CR-GNB infections.
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Assuntos
Antibacterianos , Carbapenêmicos , Bactérias Gram-Negativas , Testes de Sensibilidade Microbiana , Polimixina B , Polimixina B/farmacologia , Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Carbapenêmicos/farmacologia , Humanos , Acinetobacter baumannii/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Adjuvantes Farmacêuticos/farmacologia , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Sinergismo FarmacológicoRESUMO
Aim: To review in vitro, in vivo, and in silico studies examining the antibacterial and immunomodulatory properties of piperine (PPN). Methods: This systematic review followed PRISMA guidelines, and five databases were searched. Results: A total of 40 articles were included in this study. Six aspects of PPN activity were identified, including antibacterial spectrum, association with antibiotics, efflux pump inhibition, biofilm effects, protein target binding, and modulation of immune functions/virulence factors. Most studies focused on Mycobacterium spp. and Staphylococcus aureus. Cell lineages and in vivo models were employed to study PPN antibacterial effects. Conclusion: We highlight PPN as a potential adjuvant in the treatment of bacterial infections. PPN possesses several antibacterial properties that need further exploration to determine the mechanisms behind its pharmacological activity.
Assuntos
Alcaloides , Antibacterianos , Antibacterianos/química , Alcaloides/farmacologia , Benzodioxóis/farmacologia , Piperidinas/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
BACKGROUND: For more than 60 years, the lack of new anti-tuberculosis drugs and the increase of resistant Mycobacterium tuberculosis lineages exhibit a therapeutic challenge, demanding new options for the treatment of resistant tuberculosis. OBJECTIVE: Herein, we determined the (i) activities of (-)-camphene and its derivatives and (ii) combinatory effect with pyrazinamide (PZA) against Mycobacterium tuberculosis in acidic pH and (iii) cytotoxicity on VERO cells. METHODS: The activity of (-)-camphene and its 15 derivatives was determined in M. tuberculosis H37Rv in culture medium at pH 6.0 by Resazurin Microtiter Assay Plate (REMA). The activity and combinatory study of three (-)-camphene derivatives with PZA was carried out on seven multidrugresistant (MDR) clinical isolates by REMA and Checkerboard, respectively. The assay of 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide in VERO cells was used to determine the derivatives' cytotoxicity. RESULTS: Four (-)-camphene derivatives, (4), (5a) (5d) and (5h), showed a reduction in the MIC value at pH 6.0 compared to the MIC detected at pH 6.8 in M. tuberculosis H37Rv and multidrug resistant clinical isolates. Three (-)-camphene derivatives, (4), (5d) and (5h), showed synergistic effect (FICI ≤ 0.5) combined with PZA and were more selective for M. tuberculosis than VERO cell (selective index from 7.7 to 84.2). CONCLUSION: Three (-)-camphene derivatives have shown to be promising anti-TB molecule scaffolds due to their low MIC values in acidic pH against MDR M. tuberculosis clinical isolates, synergism with PZA and low cytotoxicity.
Assuntos
Antituberculosos/farmacologia , Monoterpenos Bicíclicos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Animais , Antituberculosos/química , Antituberculosos/toxicidade , Monoterpenos Bicíclicos/química , Monoterpenos Bicíclicos/toxicidade , Chlorocebus aethiops , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Estereoisomerismo , Células VeroRESUMO
A series of methyl ß-carboline carboxylates (2a-g) and of imide-ß-carboline derivatives containing the phthalimide (4a-g), maleimide (5b, g) and succinimide (6b, e, g) moiety were synthesized, and evaluated for their activity against Mycobacterium tuberculosis H37Rv. The most active ß-carboline derivatives against the reference strain were assayed for their cytotoxicity and the activity against resistant M. tuberculosis clinical isolates. Farther, structure-activity relationship (SAR) studies were carried out using the three and four-dimensional approaches for starting to understand the way of ß-carboline activity in M. tuberculosis. All 19 ß-carboline derivatives were assayed, firstly, by determining the minimum inhibitory concentration (MIC) using resazurin microtiter assay plate (REMA) in M. tuberculosis H37Rv. Then, five derivatives (2c, 4a, 4e, 4g, 6g), which showed MIC ≤ 125 µg/mL, were assayed in nine resistant M. tuberculosis clinical isolates (five MDR, three isoniazid monoresistant and one isoniazid plus streptomycin resistant). The MIC values against the resistant clinical isolates ranged from 31.25 to >250 µg/mL. All five derivatives were non-cytotoxic to the VERO cell line, determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, at the tested concentration (selectivity index ranged from <1.74 to 14.4). Our study demonstrated that (2c) and (6g) derivatives had better anti-M. tuberculosis activity, especially against resistant clinical isolates, what makes them scaffold candidates for further investigations about their anti-tuberculosis activity. The SAR study conducted with the 19 ß-carboline derivatives showed the importance of steric effects for the synthesized ß-carbolines against M tuberculosis, and these models can be used for future proposition of new derivatives, increasing the chances of obtaining potentially anti-tuberculosis compounds.
Assuntos
Antituberculosos/farmacologia , Carbolinas/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Animais , Antituberculosos/síntese química , Antituberculosos/química , Carbolinas/síntese química , Carbolinas/química , Chlorocebus aethiops , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Quantitativa Estrutura-Atividade , Células VeroRESUMO
The susceptibility of rapidly growing mycobacteria (RGM) to linezolid and ciprofloxacin was evaluated by using resazurin as a growth indicator. The assay with resazurin supplemented medium performed as well as its addition to the medium at reading time and was efficient for the determination for the susceptibility profile in RGM.