Novel Cephalosporin Conjugates Display Potent and Selective Inhibition of IMP Type Metallo-β-Lactamases

In an attempt to exploit the hydrolytic mechanism by which β-lactamase enzymes degrade cephalosporins, we designed and synthesized a series of novel cephalosporin prodrugs aimed at delivering thiol-based inhibitors of metallo-β-lactamases (MBLs) in spatiotemporally controlled fashion. Notably, while enzyme-mediated hydrolysis of the β-lactam ring was found to occur, it was not accompanied by release of the thiol-based inhibitors. Nonetheless, the cephalosporin prodrugs, especially thiomandelic acid conjugate (8), demonstrated potent inhibition of IMP-type MBLs, with IC50 values in the nanomolar range. In addition, conjugate 8 was also found to greatly reduce the MIC of meropenem against an IMP-28 producing clinical isolate of K. pneumoniae. The results of kinetic experiments indicate that these prodrugs inhibit IMP-type MBLs by acting as slowly turned-over substrates. Structure-activity relationship studies revealed that both phenyl and carboxyl moieties of 8 are crucial for its potency. Furthermore, modeling studies indicate that productive interactions of the thiomandelic acid moiety of 8 with residues Trp28 and Lys161 within the IMP active site may contribute to the observed inhibitory potency and selectivity.

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Rashes with Ampicillin

Pediatrics in Review ◽

10.1542/pir.1.7.197 ◽

1980 ◽

Vol 1 (7) ◽

pp. 197-201

Author(s):

Michael J. Kraemer ◽

Arnold L. Smith

Keyword(s):

Penicillin G ◽

Side Chain ◽

Gram Negative Bacteria ◽

Acid Moiety ◽

Structure Activity ◽

Body Tissues ◽

The Family ◽

Acyl Side Chain ◽

Penicillanic Acid ◽

Lactam Ring

Ampicillin, first introduced in 1961, has probably become the most widely used penicillin in clinical pediatrics. STRUCTURE ACTIVITY RELATIONSHIPS All penicillins contain the 6-amino penicillanic acid moiety (Fig 1). Its structure includes a thiazolidine ring (A), a β-lactam ring (B), the source of antibacterial activity, and an acyl side chain (R), containing a variety of substitutions creating the family of semisynthetic penicillins. The only difference between ampicillin and penicillin G is the presence of an amino group in the acyl side chain (Fig 1). PHARMACOLOGY AND BACTERIOLOGY Ampicillin is a semisynthetic penicillin, active against Streptococus pneumoniae and certain Gram-negative bacteria, including most Haemophilus influenzae, Escherichia coli, and certain Proteus species. Compared to penicillin G, it has increased stability in acid solutions: a property facilitating oral administration and absorption. It penetrates into most body tissues; effective entry into CSF, however, occurs only with inflamed meninges. The serum half-life with normal renal function varies from four hours in newborns1 to 1.3 hours in adults.2 Ampicillin can cause an allergic, or nonallergic skin rash (Fig 2). ALLERGY Allergy (for the purposes of this discussion) is defined as a specific immunologic interaction, between either antigen and antibody, or antigen with a sensitized lymphocyte, resulting in a clinically deleterious effect. Implicit is a prior contact with the antigen.

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Inhibition of human carboxylesterases by ginsenosides: structure–activity relationships and inhibitory mechanism

Chinese Medicine ◽

10.1186/s13020-019-0279-0 ◽

2019 ◽

Vol 14 (1) ◽

Cited By ~ 2

Author(s):

Zhao-Hui Sun ◽

Jing Chen ◽

Yun-Qing Song ◽

Tong-Yi Dou ◽

Li-Wei Zou ◽

...

Keyword(s):

High Selectivity ◽

Hydroxyl Groups ◽

Inhibitory Effects ◽

Docking Simulations ◽

Structure Activity ◽

Potent Inhibition ◽

Wide Range ◽

Competitive Inhibitors ◽

First Time ◽

Hydrolysis Of

Abstract Background Human carboxylesterases (hCES) are key serine hydrolases responsible for the hydrolysis of a wide range of endogenous and xenobiotic esters. Although it has been reported that some ginsenosides can modulate the activities of various enzymes, the inhibitory effects of ginsenosides on hCES have not been well-investigated. Methods In this study, more than 20 ginsenosides were collected and their inhibitory effects on hCES1A and hCES2A were assayed using the highly specific fluorescent probe substrates for each isoenzyme. Molecular docking simulations were also performed to investigate the interactions between ginsenosides and hCES. Results Among all tested ginsenosides, Dammarenediol II (DM) and 20S-O-β-(d-glucosyl)-dammarenediol II (DMG) displayed potent inhibition against both hCES1A and hCES2A, while protopanaxadiol (PPD) and protopanaxatriol (PPT) exhibited strong inhibition on hCES2A and high selectivity over hCES1A. Introduction of O-glycosyl groups at the core skeleton decreased hCES inhibition activity, while the hydroxyl groups at different sites might also effect hCES inhibition. Inhibition kinetic analyses demonstrated that DM and DMG functioned as competitive inhibitors against hCES1A-mediated d-luciferin methyl ester (DME) hydrolysis. In contrast, DM, DMG, PPD and PPT inhibit hCES2A-mediated fluorescein diacetate (FD) hydrolysis via a mixed manner. Conclusion The structure–inhibition relationships of ginsenosides as hCES inhibitors was investigated for the first time. Our results revealed that DM and DMG were potent inhibitors against both hCES1A and hCES2A, while PPD and PPT were selective and strong inhibitors against hCES2A.

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Structure activity relationships and the binding mode of quinolinone-pyrimidine hybrids as reversal agents of multidrug resistance mediated by P-gp

Scientific Reports ◽

10.1038/s41598-021-96226-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jerónimo Laiolo ◽

Priscila Ailin Lanza ◽

Oscar Parravicini ◽

Cecilia Barbieri ◽

Daniel Insuasty ◽

...

Keyword(s):

Multidrug Resistance ◽

Molecular Complexes ◽

Binding Mode ◽

Reversal Agents ◽

Structure Activity Relationships ◽

Structure Activity ◽

Doxorubicin Toxicity ◽

Key Residues ◽

Nanomolar Range ◽

Experimental Structure

AbstractP-gp-associated multidrug resistance is a major impediment to the success of chemotherapy. With the aim of finding non-toxic and effective P-gp inhibitors, we investigated a panel of quinolin-2-one-pyrimidine hybrids. Among the active compounds, two of them significantly increased intracellular doxorubicin and rhodamine 123 accumulation by inhibiting the efflux mediated by P-gp and restored doxorubicin toxicity at nanomolar range. Structure–activity relationships showed that the number of methoxy groups, an optimal length of the molecule in its extended conformation, and at least one flexible methylene group bridging the quinolinone to the moiety bearing the pyrimidine favored the inhibitory potency of P-gp. The best compounds showed a similar binding pattern and interactions to those of doxorubicin and tariquidar, as revealed by MD and hybrid QM/MM simulations performed with the recent experimental structure of P-gp co-crystallized with paclitaxel. Analysis of the molecular interactions stabilizing the different molecular complexes determined by MD and QTAIM showed that binding to key residues from TMH 4–7 and 12 is required for inhibition.

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Point-Substitution of Phenylalanine Residues of 26RFa Neuropeptide: A Structure-Activity Relationship Study

Molecules ◽

10.3390/molecules26144312 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4312

Author(s):

Benjamin Lefranc ◽

Karima Alim ◽

Cindy Neveu ◽

Olivier Le Marec ◽

Christophe Dubessy ◽

...

Keyword(s):

Receptor Activation ◽

Pharmacological Profile ◽

Acid Moiety ◽

Structural Determinants ◽

Physiological Processes ◽

Structure Activity ◽

Peptide Derivatives ◽

Targeting Peptide ◽

G Protein Coupled

26RFa is a neuropeptide that activates the rhodopsin-like G protein-coupled receptor QRFPR/GPR103. This peptidergic system is involved in the regulation of a wide array of physiological processes including feeding behavior and glucose homeostasis. Herein, the pharmacological profile of a homogenous library of QRFPR-targeting peptide derivatives was investigated in vitro on human QRFPR-transfected cells with the aim to provide possible insights into the structural determinants of the Phe residues to govern receptor activation. Our work advocates to include in next generations of 26RFa(20–26)-based QRFPR agonists effective substitutions for each Phe unit, i.e., replacement of the Phe22 residue by a constrained 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid moiety, and substitution of both Phe24 and Phe26 by their para-chloro counterpart. Taken as a whole, this study emphasizes that optimized modifications in the C-terminal part of 26RFa are mandatory to design selective and potent peptide agonists for human QRFPR.

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Additions and Corrections - Structure-Activity Relationship Studies with Symmetric Naphthalenesulfonic Acid Derivatives. Synthesis and Influence of Spacer and Naphthalenesulfonic Acid Moiety on Anti-HIV-1 Activity.

Journal of Medicinal Chemistry ◽

10.1021/jm00077a601 ◽

1993 ◽

Vol 36 (25) ◽

pp. 4130-4130 ◽

Cited By ~ 2

Author(s):

Prem Mohan ◽

Man Fai Wong ◽

Sandeep Verma ◽

Peggy Huang ◽

Anura Wickramasinghe ◽

...

Keyword(s):

Structure Activity Relationship ◽

Activity Relationship ◽

Acid Moiety ◽

Structure Activity ◽

Anti Hiv ◽

Hiv 1

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Quinolin-2-one-pyrimidine Hybrids Acting as Potent Reversal Agents on the P-gp-mediated Multidrug Resistance: Insights into Structure-activity Relationships and the Binding Mode

10.21203/rs.3.rs-451061/v1 ◽

2021 ◽

Author(s):

Jerónimo Laiolo ◽

Priscila Ailin Lanza ◽

Oscar Parravicini ◽

Cecilia Barbieri ◽

Daniel Insuasty ◽

...

Keyword(s):

Multidrug Resistance ◽

Molecular Complexes ◽

Binding Mode ◽

Reversal Agents ◽

Structure Activity Relationships ◽

Structure Activity ◽

Doxorubicin Toxicity ◽

Key Residues ◽

Nanomolar Range ◽

Experimental Structure

Abstract P-gp-associated multidrug resistance (MDR) is a major impediment to the success of chemotherapy. With the aim of finding non-toxic and effective P-gp inhibitors, we investigated a panel of quinolin-2-one-pyrimidine hybrids. Among the active compounds, two of them significantly increased intracellular doxorubicin and rhodamine 123 accumulation by inhibiting the efflux mediated by P-gp and restored doxorubicin toxicity at nanomolar range. Structure-activity relationships showed that the number of methoxy groups, an optimal length of the molecule in its extended conformation, and at least one flexible methylene group bridging the quinolinone moiety favored the inhibitory potency of P-gp. The best compounds showed a similar binding pattern and interactions to those of doxorubicin and tariquidar, as revealed by MD and hybrid QM/MM simulations performed with the recent experimental structure of P-gp co-crystallized with paclitaxel. Analysis of the molecular interactions stabilizing the different molecular complexes determined by MD and QTAIM showed that binding to key residues from TMH 4–7 and 12 is required for inhibition.

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Selective Inhibitors of Histone Deacetylase 10 (HDAC-10)

Current Medicinal Chemistry ◽

10.2174/0929867328666210901144658 ◽

2021 ◽

Vol 28 ◽

Author(s):

Eftiola Pojani ◽

Daniela Barlocco

Keyword(s):

Histone Deacetylase ◽

Cancer Chemotherapy ◽

Chemotherapy Resistance ◽

Hdac Inhibitors ◽

Selective Inhibition ◽

Epigenetic Mechanism ◽

Inhibitory Potency ◽

Chemotherapy Drugs ◽

Hydrogen Bond Interactions ◽

Class I Hdacs

: Histone acetylation balance is one epigenetic mechanism controlling gene expression associated with disease progression. It has been observed that histone deacetylase 10 (HDAC-10) isozyme contributes to the chemotherapy resistance; in addition, the poor clinical outcome observed in patients with aggressive solid tumors, such as neuroblastoma, has been associated with its overexpression. Moreover, HDAC-10 selective inhibition suppresses the autophagic response, thus providing an improved risk-benefit profile compared to cytotoxic cancer chemotherapy drugs. On these bases, HDAC-10 is becoming an emerging target for drug design. Due to the rapid progress in the development of next-generation HDAC inhibitors, this review article aims to provide an overview on novel selective or dual HDAC-8/10 inhibitors, as new leads for cancer chemotherapy, able to avoid the severe side-effects of several actual approved “pan” HDAC inhibitors. A literature search was conducted in MedLine, PubMed, Caplus, SciFinder Scholar databases from 2015 to the present. Since the disclosure that the HDAC-6 inhibitor Tubastatin A was able to bind HDAC-10 efficiently, several related analogues were synthesized and tested. Both tricyclic (25-30) and bicyclic (31-42) derivatives were considered. The best pharmacological profile was shown by 36 (HDAC-10 pIC50 = 8.4 and pIC50 towards Class I HDACs from 5.2–6.4). In parallel, based on the evidence that high levels of HDAC-8 are a marker of poor prognosis in neuroblastoma treatment, dual HDAC-8/10 inhibitors were designed. The hydroxamic acid TH34 (HDAC-8 and 10 IC50 = 1.9 µM and 7.7 µM, respectively) and the hybrid derivatives 46d, 46e and 46g were the most promising both in terms of potency and selectivity. Literature surveys indicate several structural requirements for inhibitory potency and selectivity towards HDAC-10, e.g., electrostatic and/or hydrogen bond interactions with E274 and complementarity to the P(E,A) CE motif helix.

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Rostral ventral medulla 5-HT1A receptors selectively inhibit the somatosympathetic reflex

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2001.280.5.r1261 ◽

2001 ◽

Vol 280 (5) ◽

pp. R1261-R1268 ◽

Cited By ~ 25

Author(s):

Takashi Miyawaki ◽

Ann K. Goodchild ◽

Paul M. Pilowsky

Keyword(s):

Blood Pressure ◽

Arterial Blood Pressure ◽

Sympathetic Nerve Activity ◽

Selective Inhibition ◽

Inhibitory Effect ◽

Ventrolateral Medulla ◽

Arterial Blood ◽

Potent Inhibition ◽

Somatosympathetic Reflex

The role of the 5-hydroxytryptamine (5-HT1A) receptors in the rostral ventrolateral medulla (RVLM) on somatosympathetic, baroreceptor, and chemoreceptor reflexes was examined in anesthetized rats. Microinjection of the selective 5-HT1A agonist 8-hydroxy-di- n-propylamino tetralin (8-OH-DPAT) decreased arterial blood pressure and splanchnic sympathetic nerve activity (SNA). Electrical stimulation of the hindlimb evoked early and late excitatory sympathetic responses. Bilateral microinjection in the RVLM of 8-OH-DPAT markedly attenuated both the early and late responses. This potent inhibition of the somatosympathetic reflex persisted even after SNA and arterial blood pressure returned to preinjection levels. Preinjection of the selective 5-HT1A antagonist NAN-190 in the RVLM blocked the sympathoinhibitory effect of 8-OH-DPAT and attenuated the inhibitory effect on the somatosympathetic reflex. 8-OH-DPAT injected in the RVLM did not affect baroreceptor or chemoreceptor reflexes. Our findings suggest that activation of 5-HT1A receptors in the RVLM exerts a potent, selective inhibition on the somatosympathetic reflex.

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