Discovery of Quercetin and Its Analogs as Potent OXA-48 Beta-Lactamase Inhibitors

Abstract

Carbapenem resistance in Enterobacteriaceae caused by OXA-48 β-lactamase is a growing global health threat and has rapidly spread in many regions of the world. Developing inhibitors is a promising way to overcome antibiotic resistance. However, there are few options for problematic OXA-48. Here we identified quercetin, fisetin, luteolin, 3′,4′,7-trihydroxyflavone, apigenin, kaempferol, and taxifolin as potent inhibitors of OXA-48 with IC50 values ranging from 0.47 to 4.54 μM. Notably, the structure-activity relationship revealed that the substitute hydroxyl groups in the A and B rings of quercetin and its structural analogs improved the inhibitory effect against OXA-48. Mechanism studies including enzymatic kinetic assay, isothermal titration calorimetry (ITC), and surface plasmon resonance (SPR) analysis demonstrated that quercetin reversibly inhibited OXA-48 through a noncompetitive mode. Molecular docking suggested that hydroxyl groups at the 3′, 4′ and 7 positions in flavonoids formed hydrogen-bonding interactions with the side chains of Thr209, Ala194, and Gln193 in OXA-48. Quercetin, fisetin, luteolin, and 3′,4′,7-trihydroxyflavone effectively restored the antibacterial efficacy of piperacillin or imipenem against E. coli producing OXA-48, resulting in 2–8-fold reduction in MIC. Moreover, quercetin combined with piperacillin showed antimicrobial efficacy in mice infection model. These studies provide potential lead compounds for the development of β-lactamase inhibitors and in combination with β-lactams to combat OXA-48 producing pathogen.

Potentiation of Antibiotic Activity of Aztreonam against Metallo-β-Lactamase-Producing Multidrug-Resistant Pseudomonas aeruginosa by 3-O-Substituted Difluoroquercetin Derivatives

“…In this context, quercetin drew our attention because of its potential to inhibit both efflux pumps [35,36,39,58] and β-lactamases, including ESBL [59], OXA-48 [38], and MBLs [40]. In addition, we previously demonstrated that the structural modification of the quercetin scaffold could enhance its bioactivity, and di-F-Q (1) showed significant efflux pump inhibitory activity against MDR P. aeruginosa [37].…”

“…In this context, di-F-Q (1; Figure 1) drew our attention because, compared with its parent compound (quercetin, 2; Figure 1) [35,36], di-F-Q (1) demonstrated significantly enhanced inhibitory activity against the efflux pumps of MDR P. aeruginosa [37]. Also interesting is that, albeit with low potency, quercetin (2) is capable of inhibiting β-lactamases [38][39][40]. Thus, it was anticipated that, based on the di-F-Q scaffold, a hereto unknown multitarget inhibitor might be designed which potentiates the antimicrobial activity of ATM against MDR MBL-producing P. aeruginosa.…”

Identification of α-mangostin as a potent inhibitor of β-lactamase OXA-48

“…Our previous study has demonstrated the effective inhibitory activity of quercetin, 3',4',7-trihydroxyflavone, apigenin, and other flavonoids against OXA-48 [31]. Therefore, we further screened a flavone compound library containing 500 compounds for their ability to inhibit the hydrolysis of nitrocefin by purified OXA-48 enzyme.…”

3-O-Substituted Quercetin: an Antibiotic-Potentiating Agent against Multidrug-Resistant Gram-Negative Enterobacteriaceae through Simultaneous Inhibition of Efflux Pump and Broad-Spectrum Carbapenemases

“…In this context, plant secondary metabolites have drawn special attention because of their proven safety profiles along with their synergistic antibiotic-potentiating activity. 26−29 Quercetin (1, Figure 1) is one of those compounds investigated as an MDR reversal agent, and it has been recently reported to have the potential to inhibit both efflux pumps 30−32 and β-lactamases 33,34 including carbapenemases 35 and MBLs. 36 Recently, Pal and Tripathi reported that quercetin synergistically enhanced the antimicrobial activity of meropenem, carbapenem antibiotics, against carbapenem-resistant E. coli and K. pneumoniae presumably through inhibition of carbapenemases and efflux pump activity.…”

“…Taken together, the discovery of safety-proven efflux pump inhibitors and MBL carbapenemase inhibitors are current challenges in the development of MDR reversal agents which can be utilized in the treatment of carbapenemases-resistant Gram-negatives. In this context, plant secondary metabolites have drawn special attention because of their proven safety profiles along with their synergistic antibiotic-potentiating activity. − Quercetin ( 1 , Figure ) is one of those compounds investigated as an MDR reversal agent, and it has been recently reported to have the potential to inhibit both efflux pumps − and β-lactamases , including carbapenemases and MBLs . Recently, Pal and Tripathi reported that quercetin synergistically enhanced the antimicrobial activity of meropenem, carbapenem antibiotics, against carbapenem-resistant E.…”