Biological evaluation and in silico study of benzohydrazide derivatives as paraoxonase 1 inhibitors

Serum paraoxonase 1 (PON1) is found in all mammalian species and is a calcium-dependent hydrolytic enzyme. PON1 hydrolyze several substrates, including carbonates, esters, and organophosphates. In the current study, we aimed to investigate the effect of the presynthesized benzohydrazide derivatives (1-9) on PON1 activity. Benzohydrazide compounds moderate inhibited PON1 with the half-maximal inhibitory concentration values ranging from 76.04 ± 13.51 to 221.70 ± 13.59 μM and K_I values ranging from 38.75 ± 12.21 to 543.50 ± 69.76 μM. Compound 4 (2-amino-4-chlorobenzohydrazide) showed the best inhibition (K_I  = 38.75 ± 12.21 μM). Molecular docking and ADME-Tox studies of benzohydrazide derivatives were also carried out. In this context, we hope that the results obtained in this study contribute to the determination of the side effects of current and new benzohydrazide-based pharmacological compounds to be developed.

Methyl benzoate derivatives: in vitro Paraoxonase 1 inhibition and in silico studies

Paraoxonase 1 (PON1) can metabolize some compounds such as aromatic carboxylic acid and unsaturated aliphatic esters, arylesters, cyclic carbonate, plucuronide drugs, some carbamate insecticide classes, nerve gases, and lactone compounds. Methyl benzoate has recently been shown to display potent toxicity against several insect species. In the current study, we aimed to investigate the effect of the methyl benzoate compounds (1-17) on PON1 activity. Methyl benzoate compounds inhibited PON1 with K_I values ranging from 25.10 ± 4.73 to 502.10 ± 64.72 μM. Compound 10 (methyl 4-amino-2-bromo benzoate) showed the best inhibition (K_I  = 25.10 ± 4.73 μM). Furthermore, using the ADME-Tox, Glide XP, and MM-GBSA tools of the Schrödinger Suite 2021-4, a complete ligand-receptor interaction prediction was performed to characterize the methyl benzoates (1-17), probable binding modalities versus the PON1.

Synthesis, in vitro inhibition effect of novel phthalocyanine complexes as carbonic anhydrase and paraoxonase enzyme inhibitors

The preparation and assessment of carbonic anhydrase and paraoxonase enzyme inhibition properties of 3-(2-(5-amino-4-(4-bromophenyl)-3-methyl-1H-pyrazol-1-yl)ethoxy)phthalonitrile (2) and its nitrogen-containing non-peripheral phthalocyanine derivatives (3 and 4) are reported for the first time. The new phthalonitrile and its phthalocyanine derivatives have been elucidated by FT-IR spectroscopy, 1H-NMR, [Formula: see text]C-NMR, mass and UV-vis spectroscopy. The results demonstrated that all synthesized compounds moderately inhibited carbonic anhydrase and paraoxonase enzymes. Among the compounds, the most active ones were found to be compound 4 for PON (Ki : 0.14 [Formula: see text]M), compound 3 for hCA I (Ki : 22.52 [Formula: see text]M) and compound 1 for hCA II (Ki : 13.62 [Formula: see text]M).

Benzenesulfonamide derivatives containing imine and amine groups: Inhibition on human paraoxonase and molecular docking studies

Sulfonamides known as inhibitors of many metabolic enzymes have been widely used as antimicrobial drugs for a long time. In the present study, we investigated in vitro inhibitory activities of benzenesulfonamide derivatives on human paraoxonase-I (hPON1). For this aim, PON1 was purified from human serum with a specific activity of 2603.57 EU/mg and 8.34% yield using simple chromatographic methods. The various concentrations of early-synthesized sixteen sulfonamide derivatives were tested on the paraoxonase activity. Ki values of compounds were found in the range of 0.28-357.70 µM. Compound H4 had the highest inhibitory activity on hPON1 as competitive. Estimated structure-activity relationship (SAR) for compounds was done based on different substituents and their positions in the compounds. Besides, the molecular docking analysis of compound H4 was performed to understand the binding interactions on the active site of the enzyme. According to these experimental results, compound H4 was a potential inhibitor of PON1.

Some indazoles reduced the activity of human serum paraoxonase 1, an antioxidant enzyme: in vitro inhibition and molecular modeling studies

Background: Paraoxonase 1 (PON1: EC 3.1.8.1) is a vital antioxidant enzyme against mainly atherosclerosis and many other diseases associated with oxidative stress. Thus, studies related to PON1 have an important place in the pharmacology. In this study, we aimed to evaluate the in vitro inhibition effects of some indazoles on the activity of human PON1. Methods: PON1 was purified from human serum with a specific activity of 5000 U/mg and 13.50% yield by using simple chromatographic methods. Results: The indazoles showed K_i values in a range of 26.0 ± 3.00-111 ± 31.0 μM against hPON1. All these indazoles exhibited competitive inhibition. In addition, molecular docking studies were performed in order to assess the probable binding mechanisms into the active site of hPON1. Molecular modeling studies confirmed our results. Conclusions: Inhibition of PON1 by indazoles supplies a verification to further consideration of limitation dosage of indazole molecule groups as drug.

A potential risk factor for paraoxonase 1: in silico and in-vitro analysis of the biological activity of proton-pump inhibitors†

Objectives

Proton-pump inhibitors (PPIs) are drugs commonly utilized by about 7% of adults in the world. Recent researches have shown that there are countless and severe side effects of these drugs. This situation has raised concern among clinicians and patients alike. The purpose of this study is to contribute the novel drug discovery and development technology and toxicology field by researching interactions of PPIs on paraoxonase 1.

Methods

In this study, the paraoxonase 1 enzyme was purified from human serum by using rapid and straightforward chromatographic techniques. Subsequently, the inhibition effects of pantoprazole, omeprazole, and esomeprazole, PPIs, were investigated on paraoxonase 1. Besides, molecular docking studies were performed to unravel the binding mechanism between the enzyme and drugs.

Key findings

All drugs showed potent inhibitory activities. IC50 of the drugs values were 54.780 ± 0.524, 86.470 ± 0.818 and 93.390 ± 0.885 mm and Ki constants were found as 39.895 ± 0.005 mm, 70.112 ± 0.010 mm and 78.868 ± 0.008 mm, respectively. The binding scores observed in silico studies were found to agree with the obtained from in-vitro experimental results.

Conclusions

We observed that the drugs decreased PON1 activity at low concentrations. The results show that adjusting the dosages of these medications is a crucial case for each patient. The physicians should more carefully interpret whether there is an essential indication before prescribing PPIs and, if there is, to approve the proper dosing for the situation.

The effects of some cephalosporins on acetylcholinesterase and glutathione S-transferase: an in vivo and in vitro study

BACKGROUND

Glutathione S-transferase (GST) and acetylcholinesterase (AChE) are important enzymes in the metabolism. GSTs are primarily available in phase II metabolism. AChE is vital for neurodegenerative disorders.

SUBJECTS AND METHODS

The in vitro and in vivo effects of cefoperazone sodium (CFP), cefuroxime (CXM), and cefazolin (CZO) were investigated on GST and AChE activity in the present study. GST was purified using Glutathione-Agarose affinity chromatography.

RESULTS

K_i constants of CFP, CXM, and CZO were 0.1392 ± 0.02, 1.5179 ± 0.33, and 1.006 ± 0.11 mM for GST and 0.3010 ± 0.07, 0.3561 ± 0.09, and 0.3844 ± 0.04 mM, for AChE, respectively. The most effective inhibitor was CFP for both enzymes in in vitro. CZO (50 mg/kg), CXM (25 mg/kg), and CFP (100 mg/kg) inhibit in vivo GST and AChE activities. CXM had the most effective in vivo inhibition on AChE and GST.

CONCLUSIONS

CZO, CXM, and CFP are effective AChE and GST inhibitors in both in vitro and in vivo.

Gadolinium-based contrast agents: in vitro paraoxonase 1 inhibition, in silico studies

Medications show their biological effects by interaction with enzymes, which have been known to play an essential role in the pathogenesis of many diseases. Inhibition or induction of drug metabolizing enzymes has an essential place in the drug design for many kinds of diseases including cardiovascular, neurological, metabolic, and cancer. The main goal of the current study is to contribute to this growing drug design field by observing PON1-drug interactions. In recent years, the safety of gadolinium-based contrast agents (GBCAs) used in magnetic resonance imaging (MRI) has discussed. In the present study, paraoxonase 1 (PON1) enzyme was purified from human serum by simple chromatographic methods with 4095.24 EU mg^-1 protein specific activity. The inhibitory activities of gadoteric acid, gadopentetic acid, gadoxetate disodium, and gadodiamide were investigated on PON1 activity of the enzyme. IC₅₀ values were found in the range of 51.28 ± 0.14 to 285.80 ± 0.96 mM. K_i constants were found as 67.95 ± 0.60 mM, 104.97 ± 0.96 mM, 202.33 ± 1.75 mM, and 299.43 ± 2.64 mM for gadoteric acid, gadopentetic acid, gadoxetate disodium, and gadodiamide, respectively. While the inhibition types are determined as competitive of gadoxetate disodium and gadodiamide by the Lineweaver-Burk curves, it was noncompetitive for other compounds. In addition, the molecular docking analyses of gadoxetate disodium and gadodiamide were carried out to understand the binding interactions on the active site of the PON1 enzyme. The structure-activity relationship (SAR) of the drugs was established on the basis of different substituents and their positions in the compounds.

Antibiotics Used in Patients after Surgery and Effects of Human Serum Paraoxonase-I (PON1) Enzyme Activity

Background:

Paraoxonase (PON; arilesterase, [EC 3.1.8.1]) is an enzyme from the group arilesterases (ARE). This enzyme is capable of hydrolyzing paraoxone which is the active metabolite of parathion, an organic phosphorus insecticide. PON activity was found to be low in individuals prone to development of atherosclerosis such as diabetes, familial hypercholesterolemia and kidney disorders. It was noted that PON enzyme activity decreases in relation to age increase in adults. PON enzyme activity is approximately half of that in newborns and premature babies. Approximately one year after birth, it reaches the adult level. It can be said that PON1 has significant role on living organisms. For this reason, many studies on interactions of PON-drugs are needed. </P><P> Objective: In this article, our aim is to investigate in vitro effects of four pharmaceutically active agents (fosfomycin, cefuroxime axetil, cefaclor monohydrate, and cefixime) which are often used in patients after surgery on human serum paraoxanase-I (PON1) enzyme activity.

Methods:

In this article, we purify paraoxonase-I enzyme from human serum by using ammonium sulfate precipitation (in the range of 60-80%), ion exchange and gel filtration chromatography. We use electrophoresis to check the purity of the enzyme. We investigate the paraoxonase activity of the enzyme at 412 nm the inhibition effects of the active substances. Paraoxone is used as the substrate. Activity measurements arw made at different inhibitor concentrations related to inhibitor studies and % Activity- [I] graphs are drawn for drug active substances. Lineweaver-Burk graphics are used to determine the Ki constants. Finally, to determine the types of inhibition we interpret these graphs.

Results:

The active agents used after surgery decreased the PON1 enzyme activity. They showed different inhibition mechanism. The inhibition mechanism of fosfomycin and cefaclor monohydrate was noncompetitive, cefixime was uncompetitive and cefuroxime axetil was a competitive inhibitor. The IC50 values for fosfomycin, cefuroxime axetil, cefaclor monohydrate, and cefixime were calculated to be 31.5 mM, 1.03 mM, 4.18 mM and 0.781 mM, respectively, and the Ki constants were determined to be 27.98 ± 12.25 mM, 2.20 ± 0.22 mM, 4.81 ± 2.25 mM and 1.12 ± 0.32 mM, respectively. The IC50 and Ki values showed that cefixime active agent has the maximum inhibition.

Conclusion:

In this study, we have detected that cefuroxime axetil inhibited competitively in vitro paraoxonase activity of this enzyme. According to this information, we thought that cefuroxime axetil linked to the active site of the enzyme. Fosfomycin and cefaclor monohydrate can be attached with amino acids out of the active site of the enzyme because they inhibit enzyme noncompetitively. Cefixime can be attached only to the enzyme-substrate complex because it inhibits enzyme uncompetitively.

Effect of certain non-steroidal anti-inflammatory drugs on the paraoxonase 2 (PON2) in human monocytic cell line U937

The paraoxonase gene family in humans consists of three members as PON1, PON2 and PON3. PON2 can be expressed in several tissues; however, it is not released from the cells in those tissues. PON2 is also expressed in macrophages. Firstly, the commonly used NSAIDs diclofenac sodium and tenoxicam were applied on U937 cell line, the in vitro human monocyte cell line. Than PON2 specific Lactonase activity and paraoxonase family specific arylesterase were determined. Use of Diclofenac sodium in 0.845 mM dose during 6-12 h of incubation and Tenoxicam in 0.74 mM dose during 6 h of incubation resulted in a significant decline in the lactonase activity. Diclofenac sodium didn't make any change in the arylesterase activity. On the other hand, tenoxicam decreased arylesterase activity during the use of 12 h, in 0.74 mM and 1.48 mM dose.