Antimicrobial effects of novel siderophores linked to β-lactam antibiotics
摘要:
As a strategy to increase the penetration of antibiotic drugs through the outer membrane of Gram-negative pathogens, facilitated transport through siderophore receptors has been frequently exploited. Hydroxamic acids, catechols, or very close isosteres of catechols, which are mimics of naturally occurring siderophores, have been used successfully as covalently linked escorting moieties, but a much wider diversity of iron binding motifs exists. This observation, coupled to the relative lack of specificity of siderophore receptors, prompted us to initiate a program to identify novel, noncatechol siderophoric structures. We screened over 300 compounds for their ability to (1) support growth in low iron medium of a Pseudomonas aeruginosa siderophore biosynthesis deletion mutant, or (2) compete with a bactericidal siderophore-antibiotic conjugate for siderophore receptor access. From these assays we identified a set of small molecules that fulfilled one or both of these criteria. We then synthesized these compounds with functional groups suitable for attachment to both monobactam and cephalosporin core structures. Siderophore-P-lactam conjugates then were tested against a panel of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus strains. Although several of the resultant chimeric compounds had antimicrobial activity approaching that of ceftazidime, and most compounds demonstrated very potent activity against their cellular targets, only a single compound was obtained that had enhanced, siderophore-mediated antibacterial activity. Results with tonB mutants frequently showed increased rather than decreased susceptibilities, suggesting that multiple factors influenced the intracellular concentration of the drugs. (C) 2000 Elsevier Science Ltd. All rights reserved.
involved in regulation of serum uric acid, xanthine oxidase (XO) is the best pharmacological target to control the levels of serum uric acid as it catalyzes the final steps in uric acid production. In the current study, a systemic search for the inhibitors of xanthine oxidase, starting from synthesis to in vitro screening and leading to in vivostudies is presented. Benzylidene nicotino/isonicotinohydrazides
A library of acylhydrazone iron chelators was synthesized and tested for its ability to inhibit the growth of a chloroquine-resistant strain of Plasmodium falciparum. Some of these new compounds are significantly more active than desferrioxamine DFO, the iron chelator in widespread clinical use and also than the most effective chelators. (c) 2005 Elsevier Ltd. All rights reserved.
Compounds for Targeting Cancer Stem Cells
申请人:The General Hospital Corporation
公开号:US20210238140A1
公开(公告)日:2021-08-05
This invention relates to antagonists of G3BP2, G3BP1, and ZEB1. Pharmaceutical compositions comprising G3BP2 inhibitors, methods of inhibiting G3BP2, G3BP1, and ZEB1, methods of treating cancer and inflammation, and methods of identifying an inhibitor of cancer stems cells are also provided.