MexAB-OprM specific efflux pump inhibitors in Pseudomonas aeruginosa. Part 6: Exploration of aromatic substituents
ABSTRACT A series of 4-oxo-4H-pyrido[1,2-a]pyrimidine derivatives, derivatized at the 2-position with aromatic substituents, were synthesized by the Suzuki cross-coupling method and evaluated for their ability to potentiate the activity of the fluoroquinolone levofloxacin (LVFX) and the anti-pseudomonas beta-lactam aztreonam (AZT) in Pseudomonas aeruginosa. By incorporating hydrophilic substituents onto the aryl nucleus, we found a morpholine analogue that possessed improved solubility, retained activity in vitro, and displayed potentiation activity in vivo in a rat model of P. aeruginosa pneumonia.
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ABSTRACT: Structurally diverse morpholinyl/piperazinylbenzothiazines have been synthesized in quantitative yields by the reaction of substituted 1,4-benzothiazines with morpholine/N-(2-hydroxyethyl)piperazine. 1,4-Benzothiazines were prepared by the reaction of substituted 2-aminobenzenethiols with β-ketoesters. The structures of the synthesized compounds were confirmed by their analytical and spectroscopic data. The synthesized compounds were evaluated for their antimicrobial activity against bacterial species; E. coli and Bacillus cereus. Some of the synthesized compounds have shown significant activity against microorganisms.Medicinal Chemistry Research 01/2012; 21(8). DOI:10.1007/s00044-011-9732-z · 1.61 Impact Factor
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ABSTRACT: Chemoresistance presents a general health problem concerning the therapy of infectious disease and cancer. In this context, the worldwide dissemination of “multidrugresistant” (MDR) pathogens has severely reduced the efficacy of our antimicrobial weapons and dramatically increased the frequency of therapeutic failure. Because MDR bacterial infections involve the over-expression of efflux pumps that expel unrelated antibiotics before they can reach their targets, it is necessary to clearly define the molecular and genetic bases of the MDR mechanisms in order to combat these infectious diseases. This characterization of efflux pumps allows the definition of an original anti-resistance weapon, the efflux pump inhibitor (EPI). Several chemical families of EPIs have been now described and characterized. Among them several inhibitor compounds display an efficient activity and inhibit the major AcrAB-TolC and MexAB-OprM efflux systems which are the major efflux pumps responsible for MDR Gram negative clinical isolates. The use of these EPIs induces a significant reduction of resistance to one or more antibiotics to which these isolates were initially resistant. Hence, the EPI when used as an adjuvant to the given antibiotic, restores the activity of the antibiotic. The description of the responsible efflux mechanism at its structural and physiological level will make it possible to develop along intelligent lines an improved new generation of EPIs that can readily be added to the armamentarium of current and past “fallen by the wayside” antibiotic therapies.Biochimica et Biophysica Acta 05/2009; DOI:10.1016/j.bbapap.2008.12.011 · 4.66 Impact Factor
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ABSTRACT: Multidrug-resistance efflux pumps - in particular those belonging to the resistance-nodulation-cell-division (RND) family of transporters, with their unusually high degree of substrate promiscuity - significantly restrict the effectiveness of antibacterial therapy. Recent years have heralded remarkable insights into the structure and mechanisms of these fascinating molecular machines. Here, we review recent advances in the field and describe various approaches used in combating efflux-mediated resistance.dressNature Reviews Drug Discovery 02/2007; 6(1):56-65. DOI:10.1038/nrd2200 · 37.23 Impact Factor