Inhibitory Effects of Usnic and Carnosic Acid on Some Metabolic Enzymes: An In vitro Study

Affinity gel synthesis from the p-aminobenzoic acid derivative 4-amino-2-methylbenzoic acid and purification of polyphenol oxidase from various plant sources

The polyphenol oxidase (PPO) enzyme, which causes enzymatic browning, has been repeatedly purified from fruit and vegetables by affinity chromatography. In the present research, Sepharose 4B-l-tyrosine-4-amino-2-methylbenzoic acid, a novel affinity gel for the purification of the PPO enzyme with high efficiency, was synthesized. Additionally, Sepharose 4B-l-tyrosine-p-aminobenzoic acid affinity gel, known in the literature, was also synthesized, and 9.02, 16.57, and 28.13 purification folds were obtained for the PPO enzymes of potato, mushroom, and eggplant by the reference gel. The PPO enzymes of potato, mushroom, and eggplant were purified 41.17, 64.47, and 56.78-fold from the new 4-amino-2-methylbenzoic acid gel. Following their isolation from the new affinity column, the assessment of PPO enzyme purity involved the utilization of SDS-PAGE. According to the results from SDS-PAGE and native PAGE, the molecular weight of each enzyme was 50 kDa. Then, the inhibition effects of naringin, morin hydrate, esculin hydrate, homovanillic acid, vanillic acid, phloridzin dihydrate, and p-coumaric acid phenolic compounds on purified potato, mushroom, and eggplant PPO enzyme were investigated. Among the tested phenolic compounds, morin hydrate was determined to be the most potent inhibitor on the potato (Ki: 0.07 ± 0.03 μM), mushroom (Ki: 0.7 ± 0.3 μM), and eggplant (Ki: 4.8 ± 1.2 μM) PPO enzymes. The studies found that the weakest inhibitor was homovanillic acid for the potato (Ki: 1112 ± 324 μM), mushroom (Ki: 567 ± 81 μM), and eggplant (Ki: 2016.7 ± 805.6 μM) PPO enzymes. Kinetic assays indicated that morin hydrate was a remarkable inhibitor on PPO.

The Effects of Apigenin in the Treatment of Diabetic Nephropathy: A Systematic Review of Non-clinical Studies

PURPOSE

Diabetes is one of the important and growing diseases in the world. Among the most common diabetic complications are renal adverse effects. The use of apigenin may prevent the development and progression of diabetes-related injuries. The current study aims to review the effects of apigenin in the treatment of diabetic nephropathy.

METHODS

In this review, a systematic search was performed based on PRISMA guidelines for obtaining all relevant studies on "the effects of apigenin against diabetic nephropathy" in various electronic databases up to September 2022. Ninety-one articles were obtained and screened in accordance with the predefined inclusion and exclusion criteria. Seven eligible articles were finally included in this review.

RESULTS

The experimental findings revealed that hyperglycemia led to the decreased cell viability of kidney cells and body weight loss and an increased kidney weight of rats; however, apigenin administration had a reverse effect on these evaluated parameters. It was also found that hyperglycemia could induce alterations in the biochemical and renal function-related parameters as well as histopathological injuries in kidney cells or tissue; in contrast, the apigenin administration could ameliorate the hyperglycemia-induced renal adverse effects.

CONCLUSION

The results indicated that the use of apigenin could mitigate diabetes-induced renal adverse effects, mainly through its antioxidant, anti-apoptotic, and anti-inflammatory activities. Since the findings of this study are based on experimental studies, suggesting the use of apigenin (as a nephroprotective agent) against diabetic nephropathy requires further clinical studies.

Potential Implications of Hyperoside on Oxidative Stress-Induced Human Diseases: A Comprehensive Review

Hyperoside is a flavonol glycoside mainly found in plants of the genera Hypericum and Crataegus, and also detected in many plant species such as Abelmoschus manihot, Ribes nigrum, Rosa rugosa, Agrostis stolonifera, Apocynum venetum and Nelumbo nucifera. This compound exhibits a multitude of biological functions including anti-inflammatory, antidepressant, antioxidative, vascular protective effects and neuroprotective effects, etc. This review summarizes the quantification, original plant, chemical structure and property, structure-activity relationship, pharmacologic effect, pharmacokinetics, toxicity and clinical application of hyperoside, which will be significant for the exploitation for new drug and full utilization of this compound.

Synthesis and characterization of Mg-hydroxyapatite and its cellulose hybridized structure as enhanced bio-carrier of oxaliplatin drug; equilibrium and release kinetics

An advanced form of magnesium-doped hydroxyapatite (Mg HAP) was synthesized and hybridized with cellulose fibers, producing a safe biocomposite (CF/Mg HAP) as an enhanced delivery structure of traditional oxaliplatin (OXPN) chemotherapy drug during the treatment stages of colorectal cancer. The qualifications of CF/Mg HAP as a carrier for OXPN were followed based on loading, release, and cytotoxicity as compared to Mg HAP. The CF/Mg HAP composite exhibits a notably higher OXPN encapsulation capacity (256.2 mg g-1) than the Mg HAP phase (148.9 mg g-1). The OXPN encapsulation process into CF/Mg HAP displays the isotherm behavior of the Langmuir model (R2 = 0.99) and the kinetic assumptions of pseudo-first-order kinetics (R2 > 0.95). The steric studies reflect a strong increment in the quantities of the free sites after the cellulose hybridization steps (Nm = 178.58 mg g-1) as compared to pure Mg HAP (Nm = 69.39 mg g-1). Also, the capacity of each site was enhanced to be loaded by 2 OXPN molecules (n = 1.43) in a vertical orientation. The OXPN encapsulation energy into CF/Mg HAP (<40 kJ mol-1) reflects physical encapsulation reactions involving van der Waals forces and hydrogen bonding. The OXPN release profiles of CF/Mg HAP exhibit slow and controlled properties for about 100 h, either at pH 5.5 or pH 7.4. The release kinetics and diffusion exponent (>0.45) signify non-Fickian transport and a complex erosion/diffusion release mechanism. The free CF/Mg HAP particles display a considerable cytotoxic effect on the HCT-116 cancer cells (21.82% cell viability), and their OXPN-loaded product shows a strong cytotoxic effect (1.85% cell viability).

Evaluation of in vitro effect, molecular docking, and molecular dynamics simulations of some dihydropyridine-class calcium channel blockers on human serum paraoxonase 1 (hPON1) enzyme activity

Paraoxonase 1 (PON1) was purified 148.80-fold in 37.92% yield by hydrophobic interaction chromatography technique. The purity of PON1 was checked by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) with a single band of 43 kDa. The in vitro effects of nine different calcium channel blockers on PON1 activity were evaluated. All drugs strongly decreased PON1 activity, and IC50 levels were between 13.987 ± 0.59 and 238.104 ± 2.14 μM, Ki values between 8.58 ± 0.36 and 111 ± 1.27 μM. The drugs with the strongest inhibitory effect were nisoldipine with 13.987 ± 0.59 μM and nicardipine with 20.158 ± 0.43 μM. The mechanism of action for the inhibition of the enzyme by nisoldipine and nicardipine was investigated through molecular docking. The stability of enzyme-ligand complexes obtained from the docking was explored through molecular dynamics simulation. The binding affinity of the ligands toward the enzyme was also investigated through MMPBSA (molecular mechanics Poisson-Boltzmann surface area method). The computational analysis demonstrated these compounds could inhibit the enzyme. Nisoldipine had the strongest binding, and its complex was the most stable one. Furthermore, nicardipine was found to have the highest affinity toward the enzyme.

Assessment of hypolipidemic and anti-inflammatory properties of walnut (Juglans regia) seed coat extract and modulates some metabolic enzymes activity in triton WR-1339-induced hyperlipidemia in rat kidney, liver, and heart

Atherosclerosis and cognitive impairment are both influenced by hyperlipidemia. Due to their high margin of safety and low cost, natural chemicals have recently attracted particular attention in the context of the treatment of disease. Hence, the purpose of this study was to investigate the possible amendatory impact of ethanol extract walnut (Juglans regia) seed coat (E-WSC) on some metabolic enzymes (glutathione reductase (GR), paraoxonase-1 (PON1), aldose reductase (AR), sorbitol dehydrogenase (SDH), acetylcholinesterase (AChE), glutathione S-transferase (GST), and butyrylcholinesterase (BChE)) activity in the liver, kidney, and heart of rats with Triton WR-1339-induced hyperlipidemia. Rats were divided into five groups: control group, HL-Control group (Triton WR-1339 400 mg/kg, i.p administered group), E- WSC + 150 (150 mg/kg,o.d given group), E- WSC + 300 (E- WSC 300 mg/kg, o.d given group) and HL+ E-WSC + 300 (Group receiving E- WSC 300 mg/kg, o.d 30 min prior to administration of Triton WR-1339 400 mg/kg, i.p). In HL-Control, AR, SDH, and BChE enzyme activity was significantly increased in all tissues compared to the control, while the activity of other studied enzymes was significantly decreased. The effects of hyperlipidemia on balance were improved and alterations in the activity of the investigated metabolic enzymes were prevented by E-WSC. As a result, promising natural compounds that can be used as adjuvant therapy in the treatment of cognitive disorders and hyperlipidemia may be found in E-WSC powder.

Molecular Docking Studies and the Effect of Fluorophenylthiourea Derivatives on Glutathione-Dependent Enzymes

Cancer is a serious problem affecting the health of all human societies. Chemotherapy refers to the use of drugs to kill cancer or the origin of cancer. In the past three decades, researchers have studied about proteins and their roles in the production of cancer cells. Glutathione S-transferases (GSTs) are a superfamily of enzymes that play a key role in cellular detoxification, protecting against reactive electrophiles attacks, including chemotherapeutic agents. Glutathione reductase (GR) is an important antioxidant enzyme involved in protecting the cell against oxidative stress. In this current study, GST and GR enzymes were purified from human erythrocytes using affinity chromatography. GR was obtained with a specific activity of 5.95 EU/mg protein and a 52.38 % yield. GST was obtained with a specific activity of 4.88 EU/mg protein and a 74.88 % yield. The effect of fluorophenylthiourea derivatives on the purified enzymes was investigated. Afterward, K_I values were found to range from 23.04±4.37 μM-59.97±13.45 μM for GR and 7.22±1.64 μM-41.24±2.55 μM for GST. 1-(2,6-difluorophenyl)thiourea was showed the best inhibition effect for both GST and GR enzymes. The relationships of inhibitors with 3D structures of GST and GR were explained by molecular docking studies.

Molecular docking and inhibition studies of vulpinic, carnosic and usnic acids on polyol pathway enzymes

Aldose reductase (AR) and sorbitol dehydrogenase (SDH) are important enzymes of the polyol pathway. In the current study, inhibitory effects of vulpinic acid (VA) carnosic acid (CA) and usnic acid (UA) on purified AR and SDH enzymes were determined. These enzymes inhibition could be essential to prevent diabetic complications. AR and SDH enzymes were purified from sheep kidney. Then, VA, CA and UA were tested in various concentrations against these enzymes activity in vitro. K_I values were found to be as 1.46 ± 0.04, 5.13 ± 0.25 and 11.71 ± 0.27 μΜ for VA, CA and UA, respectively, for AR. K_I constants were found to be as 15.32 ± 0.34, 145.60 ± 2.17 and 213.40 ± 2.64 μΜ VA, CA and UA, respectively, for SDH. These findings indicate that VA, CA and UA could be useful in the treatment of diabetic complications.Communicated by Ramaswamy H. Sarma.

Screening of in vitro and in silico effect of Fluorophenylthiourea compounds on glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase enzymes

Inhibition studies of enzymes in the pentose phosphate pathway (PPP) have recently emerged as a promising technique for pharmacological intervention in several illnesses. Glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) are the most important enzymes of the PPP. For this purpose, in the current study, we examined the effect of some fluorophenylthiourea on G6PD and 6PGD enzyme activity. These compounds exhibited moderate inhibitory activity against G6PD and 6PGD with K_I values ranging from 21.60 ± 8.42 to 39.70 ± 11.26 μM, and 15.82 ± 1.54 to 29.97 ± 5.72 μM, respectively. 2,6-difluorophenylthiourea displayed the most potent inhibitory effect for G6PD, and 2-fluorophenylthiourea demonstrated the most substantial inhibitory effect for 6PGD. Furthermore, the molecular docking analyses of the fluorophenylthioureas, competitive inhibitors, were performed to understand the binding interactions at the enzymes' binding site.

Ophthalmic drugs: in vitro paraoxonase 1 inhibition and molecular docking studies

Glaucoma is a neuropathy disorder and is generally treated by drugs. Allergic conjunctivitis is a common ophthalmologic disease. Paraoxonase 1 (PON1) is an organophosphate hydrolyzer and antiatherogenic enzyme. PON1 is known for preventing atherosclerosis through lipid-modifying features, as well as which has decisive actions of antiapoptosis, anti-inflammatory, antithrombosis, and antiadhesion antioxidant activity properties. Thus, reducing the enzyme levels in hyperthyroidism, chronic renal failure, glaucoma, diabetes mellitus, and cardiovascular diseases is a significant risk. This study was tested some ophthalmic drugs used to treat the diseases, such as glaucoma and allergic conjunctivitis, mentioned above, travoprost, latanoprost, ketotifen, emedastine, and olopatadine, for their inhibition activities against PON1. These drugs displayed the potent inhibition effect with IC₅₀ values ranging between 14.95 ± 0.15 and 299.60 ± 4.07 μM and K_I constants ranging from 9.71 ± 2.63 to 261.50 ± 59.98 μM. Besides, the molecular docking analyses of the competitive inhibitors, travoprost, emedastine, and olopatadine, were performed to understand the binding interactions on the enzyme's binding site. According to both in vitro and in silico analysis results, travoprost had the most potent effect on PON1 enzyme activity.

The impact of Nrf2/HO-1, caspase-3/Bax/Bcl2 and ATF6/IRE1/PERK/GRP78 signaling pathways in the ameliorative effects of morin against methotrexate-induced testicular toxicity in rats

BACKGROUND

Methotrexate (MT) is a broadly used chemotherapeutic drug however its clinical use is confronted with several forms of toxicities containing testicular damage. The current study assessed the ameliorative effects of morin on MT-induced testicular damage with the investigation of its mechanism and the potential involvement of oxidative stress, inflammation, apoptosis and endoplasmic reticulum stress in such protection.

METHODS

The animals were divided into 5 distinct groups (7 rats in each group). Group 1 was control group, group 2 received MT-only (20 mg/kg bw), group 3 received orally morin-only (100 mg/kg bw), group 4 received MT (20 mg/kg bw) + morin (50 mg/kg bw) and group 5 received MT (20 mg/kg bw) + morin (100 mg/kg). In this study, morin was administered orally for 10 days, while MT was administered intraperitoneally on the 5th day.

RESULTS

MT intoxication was linked with augmented MDA while decreased GSH levels, the enzyme activities of glutathione peroxidase, superoxide dismutase, and catalase and mRNA levels of HO-1 and Nrf2 in the testis tissues. MT injection caused inflammation in the testicular tissue via up-regulation of MAPK14, NFκB, TNF-α and IL-1β. MT application also caused apoptosis and endoplasmic reticulum stress in the testis tissue via increasing mRNA transcript levels of Bax, caspase-3, PERK, IRE1, ATF-6, GRP78 and down-regulation of Bcl-2.

CONCLUSION

Treatment with morin at a dose of 50 and 100 mg/kg considerably mitigated oxidative stress, inflammation, apoptosis and endoplasmic reticulum stress in the testicular tissue indicating that testicular damage related to MT toxicity could be modulated by morin administration.

Synthesis and Anticancer Potential of New Hydroxamic Acid Derivatives as Chemotherapeutic Agents

Histone deacetylase (HDAC) inhibitors have been shown to induce differentiation, cell cycle arrest, and apoptosis due to their low toxicity, inhibiting migration, invasion, and angiogenesis in many cancer cells. Studies show that hydroxamic acids are generally used as anticancers. For this reason, it is aimed to synthesize new derivatives of hydroxamic acids, to examine the anticancer properties of these candidate inhibitors, and to investigate the inhibition effects on some enzymes that cause multidrug resistance in cancer cells. For this reason, new (4-amino-2-methoxy benzohydroxamic acid (a), 4-amino-3-methyl benzohydroxamic acid (b), 3-amino-5-methyl benzohydroxamic acid (c)) amino benzohydroxamic acid derivatives were synthesized in this study. The effects on healthy fibroblast, lung (A549), and cervical (HeLa) cancer cells were investigated. In addition, their effects on TRXR1, GST, and GR activities, which are important for the development of chemotherapeutic strategies, were also examined. It was determined that molecule b was the most effective molecule in HeLa cancer cells with the lowest IC₅₀ value of 0.54. It was determined that molecule c was the most effective molecules for A549 and HeLa cancer cells, with the lowest IC₅₀ values of 0.78 mM and 0.25 mM, respectively. It was determined that b and c molecules directed cancer cells to necrosis rather than apoptosis. c molecule showed anticancer effect in A549 and HeLa cancer cells. It was found that molecule c significantly suppressed both GR and TRXR1 activities. In GST activities, however, inhibitors did not have a significant effect on cancer cells.

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.

Neuroprotective effects of 18β-glycyrrhetinic acid against bisphenol A-induced neurotoxicity in rats: involvement of neuronal apoptosis, endoplasmic reticulum stress and JAK1/STAT1 signaling pathway

The exposure to bisphenol A (BPA) is inevitable owing to its common use in the production of polycarbonate plastics. Studies to reduce side effects are gaining importance since BPA causes severe toxicities in important tissues such as testes, lungs, brain, liver and kidney. The current study was planned to study ameliorative effect of 18β-glycyrrhetinic acid (18β-GA) on BPA induced neurotoxicity. Fourty Wistar albino rats were divided into five equal groups as follows: I-Control group, II-18β-GA group (100 mg/kg), III- BPA group (250 mg/kg), IV-250 mg/kg BPA + 50 mg/kg 18β-GA group, V-250 mg/kg BPA + 100 mg/kg 18β-GA group. BPA intoxication was associated with increased MDA level while reduced GSH concentration, activities of glutathione peroxidase, superoxide dismutase, and catalase. BPA supplementation caused apoptosis in the brain by up-regulating caspase-3 and Bax levels and down-regulating Bcl-2. BPA also caused endoplasmic reticulum (ER) stress by increasing mRNA transcript levels of PERK, IRE1, ATF-6 and GRP78. Additionally, it was observed that BPA administration activated JAK1/STAT1 signaling pathway and levels of TNF-α, NF-κB, p38 MAPK and JNK in the brain. However, co-treatment with 18β-GA at a dose of 50 and 100 mg/kg considerably ameliorated oxidative stress, inflammation, apoptosis, ER stress and JAK1/STAT1 signaling pathway in brain tissue. Overall, the data of this study indicate that brain damage associated with BPA toxicity could be ameliorated by 18β-GA administration.

Novel metabolic enzyme inhibitors designed through the molecular hybridization of thiazole and pyrazoline scaffolds

New hybrid thiazolyl-pyrazoline derivatives (4a-k) were obtained through a facile and versatile synthetic procedure, and their inhibitory effects on the human carbonic anhydrase (hCA) isoforms I and II as well as on acetylcholinesterase (AChE) were determined. All new thiazolyl-pyrazolines showed activity at nanomolar levels as hCA I, hCA II, and AChE inhibitors, with K_I values in the range of 13.35-63.79, 7.01-115.80, and 17.89-48.05 nM, respectively. 1-[4-(4-Cyanophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4f) and 1-(4-phenylthiazol-2-yl)-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4a) against hCAs and 1-[4-(4-chlorophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4d) and 1-[4-(4-nitrophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4b) against AChE were identified as highly potent inhibitors, superior to the standard drugs, acetazolamide and tacrine, respectively. Compounds 4a-k were also evaluated for their cytotoxic effects on the L929 mouse fibroblast (normal) cell line. Moreover, a comprehensive ligand-receptor interaction prediction was performed using the ADME-Tox, Glide XP, and MM-GBSA modules of the Schrödinger Small-Molecule Drug Discovery Suite to elucidate the potential binding modes of the new hybrid inhibitors against these metabolic enzymes.

Identification of a new class of potent aldose reductase inhibitors: Design, microwave-assisted synthesis, in vitro and in silico evaluation of 2-pyrazolines

Aldose reductase (AR) acts as a multi-disease target for the design and development of therapeutic agents for the management of diabetic complications as well as non-diabetic diseases. In the search for potent AR inhibitors, the microwave-assisted synthesis of twenty new compounds with a 1,3-diaryl-5-(4-fluorophenyl)-2-pyrazoline moiety as a common fragment in their structure (1-20) was carried out efficiently. Compounds 1-20 were subjected to in vitro studies, which were conducted to assess their AR inhibitory effects and cytotoxicity towards L929 mouse fibroblast (normal) cells. Among these compounds, 1-(3-bromophenyl)-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (20) was identified as the most promising AR inhibitor with an IC₅₀ value of 0.160 ± 0.005 μM exerting competitive inhibition with a K_i value of 0.019 ± 0.001 μM as compared to epalrestat (IC₅₀ = 0.279 ± 0.001 μM; K_i = 0.801 ± 0.023 μM) and quercetin (IC₅₀ = 4.120 ± 0.123 μM; K_i = 6.082 ± 0.272 μM). Compound 20 displayed cytotoxicity towards L929 cells with an IC₅₀ value of 18.75 ± 1.06 μM highlighting its safety as an AR inhibitor. Molecular docking studies suggested that π-π stacking interactions occurred between the m-bromophenyl moiety of compound 20 and Trp21. Based on in silico pharmacokinetic studies, compound 20 was found to possess favorable oral bioavailability and drug-like properties. It can be concluded that compound 20 is a potential orally bioavailable AR inhibitor for the management of diabetic complications as well as non-diabetic diseases.

PON1 polymorphisms can predict generalized anxiety and depressed mood in patients with multiple chemical sensitivity

Background: Multiple chemical sensitivity (MCS) is a chronic condition with somatic, cognitive and affective symptoms that follow contact with chemical agents at usually non toxic concentrations. We aimed to assess the role of genetic polymorphisms involved in oxidative stress on anxiety and depression in MCS. Materials & methods: Our study investigated the CAT rs1001179, MPO rs2333227, PON1 rs662 and PON1 rs705379 polymorphisms in MCS. Results: The AG genotype of the PON1 rs662 and the TT and CT genotypes of the PON1 rs705379 were involved in anxiety and depression. Discussion: These results are in line with existing evidence of PON1 involvement in MCS and suggest a further role of this gene in the exhibition of anxiety and depression in this disease.

The effect of brimonidine and proparacaine on metabolic enzymes: Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and glutathione reductase

Oxidative stress is to upregulate the pentose phosphate pathway (PPP). The PPP consists of two functional branches, glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconaste dehydrogenase (6PGD). Glutathione reductase (GR) has a significant role in catalyzing an oxidized glutathione form into a reduced form. The purpose of this study is to investigate the effects of brimonidine and proparacaine on the activity of 6PGD, G6PD, and GR enzymes purified from human erythrocytes. Brimonidine displayed considerable inhibition profile against G6PD with IC₅₀ value and K_I constant of 29.93 ± 3.56 and 48.46 ± 0.66 μM, respectively. On the other hand, proparacaine had no inhibitory effect against G6PD. K_I values were found to be 66.06 ± 0.78 and 811.50 ± 11.13 μM for brimonidine and proparacaine, respectively, for 6PGD. K_I values were found to be 144.10 ± 2.01 and 1,654.00 ± 26.29 μM for brimonidine and proparacaine, respectively, for GR. Herein, also in silico molecular docking studies were performed between drugs and enzymes.

Determination of the inhibition profiles of pyrazolyl-thiazole derivatives against aldose reductase and α-glycosidase and molecular docking studies

Aldose reductase (AR) is the first and rate-limiting enzyme of the polyol pathway, which converts glucose to sorbitol in an NADPH-dependent reaction. α-Glycosidase breaks down starch and disaccharides to glucose. Hence, inhibition of these enzymes can be regarded a considerable approach in the treatment of diabetic complications. AR was purified from sheep liver using simple chromatographic methods. The inhibitory effects of pyrazolyl-thiazoles ((3aR,4S,7R,7aS)-2-(4-{1-[4-(4-bromophenyl)thiazol-2-yl]-5-(aryl)-4,5-dihydro-1H-pyrazol-3-yl}phenyl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione derivatives; 3a-i) on AR and α-glycosidase enzymes were investigated. All compounds showed a good inhibitory action against AR and α-glycosidase. Among these compounds, compound 3d exhibited the best inhibition profiles against AR, with a K_i value of 7.09 ± 0.19 µM, whereas compound 3e showed the lowest inhibition effects, with a K_i value of 21.89 ± 1.87 µM. Also, all compounds showed efficient inhibition profiles against α-glycosidase, with K_i values in the range of 0.43 ± 0.06 to 2.30 ± 0.48 µM, whereas the K_i value of acarbose was 12.60 ± 0.78 µM. Lastly, molecular modeling approaches were implemented to predict the binding affinities of compounds against AR and α-glycosidase. In addition, the ADME analysis of the molecules was performed.

Molecular Docking Studies and Inhibition Properties of Some Antineoplastic Agents against Paraoxonase-I

Background:

Currently, most of the drugs used in clinical applications show their pharmacological influences by inhibiting or activating enzymes. Therefore, enzyme inhibitors have an essential place in the drug design for many diseases.

Objective:

The current study aimed to contribute to this growing drug design field (i.e., medicine discovery and development) by analyzing enzyme-drug interactions.

Methods:

For this reason, Paraoxonase-I (PON1) enzyme was purified from fresh human serum by using rapid chromatographic techniques. Additionally, the inhibition effects of some antineoplastic agents were researched on the PON1.

Results:

The enzyme was obtained with a specific activity of 2603.57 EU/mg protein. IC50 values for pemetrexed disodium, irinotecan hydrochloride, dacarbazine, and azacitidine were determined to be 9.63μM, 30.13μM, 53.31μM, and 21.00mM, respectively. These agents found to strongly inhibit PON1, with Ki constants ranging from 8.29±1.47μM to 23.34±2.71mM. Dacarbazine and azacitidine showed non-competitive inhibition, while other drugs showed competitive inhibition. Furthermore, molecular docking was performed using maestro for these agents. Among these, irinotecan hydrochloride and pemetrexed disodium possess the binding energy of -5.46 and -8.43 kcal/mol, respectively.

Conclusion:

The interaction studies indicated that these agents with the PON1 possess binding affinity.

Purification of Polyphenol Oxidase from Potato and Investigation of the Inhibitory Effects of Phenolic Acids on Enzyme Activity

Background:

Polyphenol Oxidase (PPO) belongs to the oxidoreductase enzyme family.

Methods:

Here, PPO was purified from potato using Sepharose 4B-L-tyrosine-p-aminobenzoic acid affinity chromatography. It determined the interactions between some phenolic acids and the enzyme.

Results:

The enzyme was obtained with a specific activity of 15333.33 EU/mg protein and 7.87- fold purification. It was found that phenolic acids exhibited inhibitory properties for PPO. The IC50 values of the phenolic acids were found in the range of 0.36-2.12 mM, and their Ki values were found in the range of 0.28± 0.07-1.72±0.32 mM. It was determined that all studied compounds displayed a competitive inhibition effect. Among these compounds, 3-hydroxybenzoic acid was found to be the most effective PPO inhibitor (Ki: 0.28±0.07 mM).

Conclusion:

Investigating the inhibition kinetics of the enzyme will simplify the testing of PPO inhibitor candidates.

Differential effects of selective serotonin reuptake inhibitors on paraoxonase-1 enzyme activity: An in vitro study

Paraoxonase-I (PON1) is a calcium-dependent hydrolytic enzyme, plays an important role in most antioxidant properties related to high-density lipoprotein (HDL). Antidepressant drugs are commonly employed in treatment of mood disorders and anxiety treatment. In this study, human serum PON1 was purified using simple reproducible procedures and the effects of some antidepressant drugs on its activity were determined. It was found that mirtazapine, aripiprazole, escitalopram, and risperidone exhibited potential inhibitory properties on the purified PON1 activity with IC₅₀ values in the range of 115.50-231.00 μM and K_i values in the range of 41.66 ± 4.27 μM-276.36 ± 35.28 μM. Both risperidone and escitalopram inhibited PON1 activity competitively, while both aripiprazole and mirtazapine inhibited PON1 activity non-competitively. Chlorpromazine did not affect PON1 activity. Usage of drugs with significant biological activity may be hazardous in some cases.

Inhibition effects of some antidepressant drugs on pentose phosphate pathway enzymes

The glucose metabolism in the pentose cycle is essential to the source of NADPH. Deficiency of these enzymes have been linked to depression and psychotic disorders. Depression is an increasingly prevalent mental disorder which may cause loss of labor. Antidepressant drugs are commonly employed in treatments of mood disorders and anxiety treatment. The purpose of this study is to investigate the effects of aripiprazole, mirtazapine, risperidone, escitalopram and haloperidol on the activity of 6-phosphogluconate dehydrogenase (6PGD) and glucose-6-phosphate dehydrogenase (G6PD) enzymes purified from human erythrocytes. It was found that aripiprazole, mirtazapine, risperidone, escitalopram and haloperidol show effective inhibitor properties on purified G6PD and 6PGD enzymes. The IC₅₀ values of these drugs were found in the range of 26.34 μM-5.78 mM for 6PGD and 16.26 μM-3.85 mM for G6PD. The K_i values of the drugs were found in the range of 30.21 ± 4.31 μM-4.51 ± 1.83 mM for 6PGD and 14.12 ± 3.48 μM-4.98 ± 1.14 mM for G6PD. Usage of drugs with significant biological effects may be a hazard in some conditions.

The effects of zingerone against vancomycin-induced lung, liver, kidney and testis toxicity in rats: The behavior of some metabolic enzymes

In this study, it was demonstrated the ameliorative effect of zingerone (ZO) (25 and 50 mg/kg body weight) against vancomycin (VCM) (200 mg/kg body weight) administered to rats on some metabolic enzymes' activities in the lung, liver, kidney, and testis tissues of rats. Forty-two rats were divided into six groups as follows: control, ZO-25, ZO-50, VCM, VCM + ZO-25, and VCM + ZO-50. α-Glycosidase, butyrylcholinesterase, aldose reductase, acetylcholinesterase, paraoxonase-1, and carbonic anhydrase enzyme activities were significantly (P < .05) decreased in VCM group when compared with the control group. ZO, supplied with VCM, significantly activated some of these enzyme in all tissues. The results of this study showed that ZO regulates abnormal increases and decreases in VCM-induced metabolic enzyme activities in all tissues.

Antidiabetic properties of dietary phenolic compounds: Inhibition effects on α-amylase, aldose reductase, and α-glycosidase

Aldose reductase (AR), α-amylase, and α-glycosidase are vital enzymes to prevent diabetic complications. Here, AR was purified from sheep kidney using elementary methods with 111.11-purification fold and with 0.85% purification yield. The interactions between some phenolic compounds and the AR, α-glycosidase, and α-amylase enzyme were determined. It was found that phenolic compounds exhibit potential inhibitor properties for these enzymes. For α-amylase, studied phenolic compounds showed IC₅₀ values in the range of 601.56-2,067.78 nM. For α-glycosidase, K_i values were found in the range of 169.25 ± 27.22-572.88 ± 106.76 nM. For AR, K_i values in the range of 8.48 ± 0.56-43.26 ± 7.63 µM. However, genistein showed the best inhibition effect toward AR and α-glycosidase, but delphinidin chloride exhibited the best inhibition effect against α-amylase enzyme. We determined that all compounds showed noncompetitive inhibition effect against AR and α-glycosidase. Also, studied phenolic compounds may be useful in the prevention or treatment of diabetic complications.

The behaviour of some antihypertension drugs on human serum paraoxonase-1: an important protector enzyme against atherosclerosis

Objectives

Paraoxonase-1 (PON1) enzyme is related to high-density lipoprotein (HDL), which is calcium dependent. It has essential roles such as protecting LDL against oxidation and detoxification of highly toxic substances. It is a significant risk to reduce the levels of this enzyme in patients with diabetes mellitus, cardiovascular diseases, hyperthyroidism and chronic renal failure.

Methods

Here, it was reported that the purification of human serum PON1 using straightforward methods and determination of the interactions between some antihypertension drugs and the enzyme.

Key finding

It was found that these drugs exhibit potential inhibitor properties for human serum PON1 with IC50 values in the range of 131.40–369.40 μm and Ki values in the range of 56.24 ± 6.75–286.74 ± 28.28 μm. These drugs showed different inhibition mechanisms. It was determined that midodrine and nadolol were exhibited competitive inhibition, but atenolol and pindolol were exhibited non-competitive inhibition.

Conclusion

Usage of these drugs would be hazardous in some cases.

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.

Synthesis, biological evaluation and in silico studies of novel N-substituted phthalazine sulfonamide compounds as potent carbonic anhydrase and acetylcholinesterase inhibitors

The synthesis, characterization and biological evaluation of a series of novel N-substituted phthalazine sulfonamide (5a-l) are disclosed. Phthalazines which are nitrogen-containing heterocyclic compounds are biologically preferential scaffolds, endowed with versatile pharmacological activity, such as anti-inflammatory, cardiotonic vasorelaxant, anticonvulsant, antihypertensive, antibacterial, anti-cancer action. The compounds were investigated for the inhibition against the cytosolic hCA I, II and AChE. Most screened sulfonamides showed high potency in inhibiting hCA II, widely involved in glaucoma, epilepsy, edema, and other pathologies (K_is in the ranging from 6.32 ± 0.06 to 128.93 ± 23.11 nM). hCA I was inhibited with K_is in the range of 6.80 ± 0.10-85.91 ± 7.57 nM, whereas AChE in the range of 60.79 ± 3.51-249.55 ± 7.89 nM. ADME prediction study of the designed N-substituted phthalazine sulfonamides showed that they are not only with carbonic anhydrase and acetylcholinesterase inhibitory activities but also with appropriate pharmacokinetic, physicochemical parameters and drug-likeness properties. Also, in silico docking studies were investigated the binding modes of selected compounds, to hCA I, II, and AChE.