Synthesis and investigation of the conversion reactions of pyrimidine‐thiones with nucleophilic reagent and evaluation of their acetylcholinesterase,carbonic anhydrase inhibition,and antioxidant activities

The conversion reactions of pyrimidine‐thiones with nucleophilic reagent were studied during this scientific research. For this purpose, new compounds were synthesized by the interaction between 1,2‐epoxy propane, 1,2‐epoxy butane, and 4‐chlor‐1‐butanol and pyrimidine‐thiones. These pyrimidine‐thiones derivatives ( A–K ) showed good inhibitory action against acetylcholinesterase (AChE), and human carbonic anhydrase (hCA) isoforms I and II. AChE inhibition was in the range of 93.1 ± 33.7–467.5 ± 126.9 nM. The hCA I and II were effectively inhibited by these compounds, with K_i values in the range of 4.3 ± 1.1–9.1 ± 2.7 nM for hCA I and 4.2 ± 1.1–14.1 ± 4.4 nM for hCA II. On the other hand, acetazolamide clinically used as CA inhibitor showed K_i value of 13.9 ± 5.1 nM against hCA I and 18.1 ± 8.5 nM against hCA II. The antioxidant activity of the pyrimidine‐thiones derivatives ( A–K ) was investigated by using different in vitro antioxidant assays, including Cu²⁺ and Fe³⁺ reducing, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH^?) radical scavenging, and Fe²⁺ chelating activities.     

Inhibitory effects of some drugs on carbonic anhydrase enzyme purified from Kangal Akkaraman sheep in Sivas,Turkey

In this study, carbonic anhydrase (CA) enzyme was purified and characterized from blood samples of Kangal Akkaraman sheep and inhibitory properties on certain antibiotics were examined. CA purification was composed of preparation of the hemolysate and conducting the Sepharose‐4B‐tyrosine‐sulfanilamide affinity gel chromatography in having specific activity of 11626 EU mg^?1, yield of 14.40%, and 242.76‐fold purification. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis was performed to assess the enzyme purity and a single band was observed. Some antibiotics were exhibited in vitro inhibition on the CA activity. IC₅₀ values of these inhibitors were calculated by plotting activity percentage. IC₅₀ values of certain drugs (dexamethasone; caffeine; metamizole sodium; tetramisol; ceftiofur HCl; ivermectin; tavilin 50; penokain G; neosym; and sulfamezathine) were found as 0.38, 8.24, 285.53, 114.77, 5.33, 2.76, 27.58, 213.50, 208.28, and 36.60 μM, respectively. K_i values of different drugs on Kangal Akkaraman sheep blood CA activity were found in the range of 0.21 ± 0.038–266.64 ± 37.11 μM.     

Issue information

Benzothiazepine compounds have a wide range of applications such as antibacterial, antidepressants, anticonvulsants, antihypertensives, antibiotics, antifungal, hypnotic, enzyme inhibitors, antitumor, anticancer and anti‐HIV agents. In this study, the synthesis of novel tetralone‐based benzothiazepine derivatives ( 1–16 ) and their in vitro antibacterial activity and human carbonic anhydrase isoenzymes I and II (hCA I and II) inhibitory effects were investigated. Both isoenzymes were purified by sepharose‐4B‐l ‐tyrosine‐sulfanilamide affinity chromatography from fresh human red blood cells. All compounds demonstrated the low nanomolar inhibitory effects on both isoenzymes using esterase activity. Benzothiazepine derivative 2 demonstrated the best hCA I inhibitory effect with K_i value of 18.19 nM. Also, benzothiazepine derivative 7 showed the best hCA II inhibitory effect with K_i value of 11.31 nM. On the other hand, acetazolamide clinically used as CA inhibitor, showed K_i value of 19.92 nM against hCA I and 33.60 nM against hCA II, respectively.     

The human carbonic anhydrase isoenzymes I and II inhibitory effects of some hydroperoxides,alcohols, and acetates

The carbonic anhydrases (CAs, EC 4.2.1.1) represent a superfamily of widespread enzymes, which catalyze a crucial biochemical reaction, the reversible hydration of carbon dioxide to bicarbonate and protons. Human CA isoenzymes I and II (hCA I and hCA II) are ubiquitous cytosolic isoforms. In this study, a series of hydroperoxides, alcohols, and acetates were tested for the inhibition of the cytosolic hCA I and II isoenzymes. These compounds inhibited both hCA isozymes in the low nanomolar ranges. These compounds were good hCA I inhibitors (K_is in the range of 24.93–97.99?nM) and hCA II inhibitors (K_is in the range of 26.04–68.56?nM) compared to acetazolamide as CA inhibitor (K_i: 34.50?nM for hCA I and K_i: 28.93?nM for hCA II).     

Inhibition Profiles of Some Symmetric Sulfamides Derived from Phenethylamines on Human Carbonic Anhydrase I,and II Isoenzymes

In this work, the inhibitory effect of some symmetric sulfamides derived from phenethylamines were determined against human carbonic anhydrase (hCA) I, and II isoenzymes, and compared with standard compound acetazolamide. IC₅₀ values were obtained from the Enzyme activity (%)-[Symmetric sulfamides] graphs. Also, K_i values were calculated from the Lineweaver-Burk graphs. Some symmetric sulfamides compounds ( 11 – 18 ) demonstrated excellent inhibition effects against hCA I, and II isoenzymes. These compounds demonstrated effective inhibitory profiles with IC₅₀ values in ranging from 21.66–28.88 nM against hCA I, 14.44–30.13 nM against hCA II. Among these compounds, the best K_i value for hCA I (K_i: 8.34±1.60 nM) and hCA II (K_i: 16.40±1.00 nM) is compound number 11 . Besides, the IC₅₀ value of acetazolamide used as a standard was determined as hCA I, hCA II 57.75 nM, 49.50 nM, respectively. Moreover, in silico ADME-Tox study showed that all synthesized compounds ( 11 – 18 ) had good oral bioavailability in light of Jorgensen's rule of three, and of Lipinski's rule of five.     

Novel N‐propylphthalimide‐ and 4‐vinylbenzyl‐substituted benzimidazole salts: Synthesis,characterization, and determination of their metal chelating effects and inhibition profiles against acetylcholinesterase and carbonic anhydrase enzymes

The novel N‐propylphthalimide‐substituted and 4‐vinylbenzyl‐substituted N‐heterocyclic carbene (NHC) precursors were synthesized by N‐substituted benzimidazolium with aryl halides. The novel N‐propylphthalimide‐substituted and 4‐vinylbenzyl‐substituted NHC precursors have been characterized by using ¹H NMR, ¹³C NMR, FTIR spectroscopy, and elemental analysis techniques. They were tested for the inhibition of AChE and hCA enzymes and demonstrated efficient inhibition profiles with K_i values in the range of 351.0–1269.9 nM against hCA I, 346.6–1193.1 nM against hCA II, and 19.0–76.3 nM against AChE. On the other hand, acetazolamide, a clinically used molecule, utilized as CA inhibitor, obtained a K_i value of 1246.7 nM against hCA I and 1407.6 nM against hCA II. Additionally, tacrine inhibited AChE and obtained a K_i value of 174.6 nM.     

Characterization and inhibition effects of some metal ions on carbonic anhydrase enzyme from Kangal Akkaraman sheep

In this work, the carbonic anhydrase (CA) enzyme was purified from Kangal Akkaraman sheep in Sivas, Turkey with specific activity value of 6681.57 EU/mg and yield of 14.90% with using affinity column chromatography. For designating the subunit molecular mass and enzyme purity, sodium dodecyl sulfate polyacrylamide gel electrophoresis method was used and single band for this procedure was obtained. The molecular mass of CA enzyme was found as 28.89 kDa. In this study, the optimum temperature and optimum pH were obtained from 30 and 7.5. V_max and K_m values for p‐nitrophenylacetate substrate of the CA were determined from Lineweaver–Burk graphs. Additionally, the inhibitory results of diverse heavy metal ions (Hg⁺, Fe²⁺, Pb²⁺, Co²⁺, Ag⁺, and Cu²⁺) on sheep were studied. Indeed, CA enzyme activities of Kangal sheep were investigated with using esterase procedure under in vitro conditions. The heavy metal concentrations inhibiting 50% of enzyme activity (IC₅₀) and K_i values were obtained.     

Synthesis of 2‐amino‐3‐cyanopyridine derivatives and investigation of their carbonic anhydrase inhibition effects

The conversion of carbon dioxide (CO₂) and bicarbonate (HCO₃⁻) to each other is very important for living metabolism. Carbonic anhydrase (CA, E.C.4.2.1.1), a metalloenzyme familly, catalyzes the interconversion of these ions (CO₂ and HCO₃⁻) and are very common in living organisms. In this study, a series of novel 2‐amino‐3‐cyanopyridines supported with some functional groups was synthesized and tested as potential inhibition effects against both cytosolic human CA I and II isoenzymes (hCA I and II) using by Sepharose‐4B‐l ‐tyrosine‐sulfanilamide affinity chromatography. The structural elucidations of novel 2‐amino‐3‐cyanopyridines were achieved by NMR, IR, and elemental analyses. K _i values of the novel synthesized compounds were found in range of 2.84–112.44 μM against hCA I and 2.56–31.17 μM against hCA II isoenzyme. While compound 7d showed the best inhibition activity against hCA I (K _i: 2.84 μM), the compound 7b demonstrated the best inhibition profile against hCA II isoenzyme (K _i: 2.56 μM).     

The impact of hydroquinone on acetylcholine esterase and certain human carbonic anhydrase isoenzymes (hCA I,II, IX,and XII)

Abstract

Carbonic anhydrases (CAs) are widespread and the most studied members of a great family of metalloenzymes in higher vertebrates including humans. CAs were investigated for their inhibition of all of the catalytically active mammalian isozymes of the Zn²⁺-containing CA, (CA, EC 4.2.1.1). On the other hand, acetylcholinesterase (AChE. EC 3.1.1.7), a serine protease, is responsible for ACh hydrolysis and plays a fundamental role in impulse transmission by terminating the action of the neurotransmitter ACh at the cholinergic synapses and neuromuscular junction. In the present study, the inhibition effect of the hydroquinone (benzene-1,4-diol) on AChE activity was evaluated and effectively inhibited AChE with K_i of 1.22?nM. Also, hydroquinone strongly inhibited some human cytosolic CA isoenzymes (hCA I and II) and tumour-associated transmembrane isoforms (hCA IX, and XII), with K_is in the range between micromolar (415.81?μM) and nanomolar (706.79?nM). The best inhibition was observed in cytosolic CA II.     

Investigation of the effects of some sulfonamides on acetylcholinesterase and carbonic anhydrase enzymes

Human carbonic anhydrase I and II isoenzymes (hCA I and II) and acetylcholinesterase (AChE) are important metabolic enzymes that are closely associated with various physiological and pathological processes. In this study, we investigated the inhibition effects of some sulfonamides on hCA I, hCA II, and AChE enzymes. Both hCA isoenzymes were purified by Sepharose‐4B‐L‐Tyrosine‐5‐amino‐2‐methylbenzenesulfonamide affinity column chromatography with 1393.44 and 1223.09‐folds, respectively. Also, some inhibition parameters including IC₅₀ and K_i values were determined. Sulfonamide compounds showed IC ₅₀ values of in the range of 55.14 to 562.62 nM against hCA I, 55.99 to 261.96 nM against hCA II, and 98.65 to 283.31 nM against AChE. K_i values were in the range of 23.40 ± 9.10 to 365.35 ± 24.42 nM against hCA I, 45.87 ± 5.04 to 230.08 ± 92.23 nM against hCA II, and 16.00 ± 45.53 to 157.00 ± 4.02 nM against AChE. As a result, sulfonamides had potent inhibition effects on these enzymes. Therefore, we believe that these results may contribute to the development of new drugs particularly in the treatment of some disorders.     

Purification and characterization of a trypsin-like enzyme with fibrinolytic activity present in the abdomen of horn fly, Haematobia irritans irritans (Diptera: Muscidae)

This work describes the purification and characterization of a trypsin-like enzyme with fibrinolytic activity present in the abdomen of Haematobia irritans irritans (Diptera: Muscidae). The enzyme was purified using a one-step process, consisting of affinity chromatography on SBTI-Sepharose. The purified protease showed one major active proteinase band on reverse zymography with 0.15% gelatin, corresponding to a molecular mass of 25.5 kDa, with maximum activity at pH 9.0. The purified trypsin-like enzyme preferentially hydrolyzed synthetic substrates with arginine residue at the P1 position. The K _m values determined for three different substrates were 1.88 × 10^–4, 1.28 × 10^–4, and 1.40 × 10^–4 M for H--benzoyl-Ile-Glu-Gly-Arg-p-nitroanilide (S2222), dl-Ile-Pro-Arg-p-nitroanilide (S2288), and DL-Phe-Pip-Arg-p-nitroanilide (S2238), respectively. The enzyme was strongly inhibited by typical serine proteinase inhibitors such as SBTI (soybean trypsin inhibitor, K _i = 0.19 nM) and BuXI (Bauhinia ungulata factor Xa inhibitor, K _i = 0.48 nM), and less inhibited by LDTI (leech-derived tryptase inhibitor, K _i = 1.5 nM) and its variants LDTI 2T and 5T (0.8 and 1.5 nM, respectively). The most effective inhibitor for this protease was r-aprotinin (r-BPTI) with a K _i value of 39 pM. Synthetic serine protease inhibitors presented only weak inhibition, e.g., benzamidine with K _i = 3.0 × 10^–4 M and phenylmethylsulfonyl fluoride (PMSF) showed traces of inhibition. The purified trypsin-like enzyme also digested natural substrates such as fibrinogen and fibrin net. The protease showed higher activity against fibrinogen and fibrin than did bovine trypsin. These data suggest that the proteolytic enzyme of H. irritans irritans is more specific to proteins from blood than are the vertebrate digestive enzymes. This enzyme's characteristics may be an adaptation resulting from the feeding behavior of this hematophagous insect.     

Synthesis and inhibitory properties of some carbamates on carbonic anhydrase and acetylcholine esterase

A series of carbamate derivatives were synthesized and their carbonic anhydrase I and II isoenzymes and acetylcholinesterase enzyme (AChE) inhibitory effects were investigated. All carbamates were synthesized from the corresponding carboxylic acids via the Curtius reactions of the acids with diphenyl phosphoryl azide followed by addition of benzyl alcohol. The carbamates were determined to be very good inhibitors against for AChE and hCA I, and II isoenzymes. AChE inhibition was determined in the range 0.209–0.291?nM. On the other hand, tacrine, which is used in the treatment of Alzheimer’s disease possessed lower inhibition effect (K_i: 0.398?nM). Also, hCA I and II isoenzymes were effectively inhibited by the carbamates, with inhibition constants (K_i) in the range of 4.49–5.61?nM for hCA I, and 4.94–7.66?nM for hCA II, respectively. Acetazolamide, which was clinically used carbonic anhydrase (CA) inhibitor demonstrated K_i values of 281.33?nM for hCA I and 9.07?nM for hCA II. The results clearly showed that AChE and both CA isoenzymes were effectively inhibited by carbamates at the low nanomolar levels.     

Discovery of potent carbonic anhydrase,acetylcholinesterase, and butyrylcholinesterase enzymes inhibitors: The new amides and thiazolidine‐4‐ones synthesized on an acetophenone base

Compounds containing nitrogen and sulfur atoms can be widely used in various fields, including industry, medicine, biotechnology, and chemical technology. Among them, amides of acids and heterocyclic compounds have an important place. These amides and thiazolidine‐4‐ones showed good inhibitory action against butyrylcholinesterase (BChE), acetylcholinesterase (AChE), and human carbonic anhydrase isoforms. AChE exists at high concentrations in the brain and red blood cells. BChE is an important enzyme that is plentiful in the liver, and it is released into the blood in a soluble form. They were demonstrated to have effective inhibition profiles with K_i values of 23.76–102.75 nM against hCA I, 58.92–136.64 nM against hCA II, 1.40–12.86 nM against AChE, and 9.82–52.77 nM against BChE. On the other hand, acetazolamide showed K_i value of 482.63 ± 56.20 nM against hCA I, and 1019.60 ± 163.70 nM against hCA II. Additionally, Tacrine inhibited AChE and BChE, showing K_i values of 397.03 ± 31.66 and 210.21 ± 15.98 nM, respectively.     

Inhibition effects of pesticides on glutathione‐S‐transferase enzyme activity of Van Lake fish liver

Glutathione‐S‐transferases (GSTs) have a function in xenobiotic metabolism. They are a significant multifunctional family with a wide variety of catalytic activities. In the current study, we determined in vitro inhibition effects of 2,4‐dichlorophenoxyacetic acid dimethylamine salt (2,4‐D DMA), haloxyfop‐P‐methyl, glyphosate isopropylamine, dichlorvos, and λ‐cyhalothrin on purified GST. For this purpose, GST were purified from Van Lake fish (Chalcalburnus tarichii Pallas) liver with 29.25 EU mg^?1 specific activity and 10.76% yield using GSH–agarose affinity chromatographic method. The pesticides were tested at various concentrations on in vitro GST activity. K_i constants were calculated as 0.17 ± 0.01, 0.25 ± 0.05, 3.72 ± 0.32, 0.42 ± 0.06, and 0.025 ± 0.004 mM, for 2,4‐D DMA, haloxyfop‐P‐methyl, glyphosate isopropylamine, dichlorvos, and λ‐cyhalothrin, respectively. λ‐Cyhalothrin showed a better inhibitory effect compared to the other pesticides. The inhibition mechanisms of λ‐cyhalothrin were competitive, while the other pesticides were noncompetitive.     

Purification and Characterization of Carbonic Anhydrase from Ağrı Balık Lake Trout Gill (Salmo trutta labrax) and Effects of Sulfonamides on Enzyme Activity

Carbonic anhydrase (CA) was purified from A?r? Bal?k Lake trout gill (fCA) by affinity chromatography on a sepharose 4B‐tyrosine‐sulfanilamide column. The fCA enzyme was purified with about a 303.9 purification factor, a specific activity 4130.4 EU (mg‐protein)^–1, and a yield of 79.3 by using sepharose‐4B‐l tyrosine‐sulfanilamide affinity gel chromatography. The molecular weight determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) was found to be about 29.9 kDa. The kinetic parameters, K_M and V_max were determined for the 4‐nitrophenyl acetate hydrolysis reaction. Some sulfonamides were tested as inhibitors against the purified CA enzymes. The K_i constants for mafenide ( 1 ), p‐toluenesulfonamide ( 2 ), 2‐bromo‐benzene sulfonamide ( 3 ), 4‐chlorobenzene sulfonamide ( 4 ), 4‐amino‐6‐chloro‐1–3 benzenedisulfonamide ( 5 ), sulfamethazine ( 6 ), sulfaguanidine ( 7 ), sulfadiazine ( 8 ), and acetozazolamide ( 9 ) were in the range of 7.5–108.75 μM.     

Macrocyclic lactones: distribution in plasma lipoproteins of several animal species including humans

We studied the in vitro distribution of macrocyclic lactones (MLs), lipophilic anthelmintic drugs, in the plasma of several animal species including humans. First, in vitro spiking of goat plasma was performed with ivermectin, moxidectin, abamectin, doramectin, or eprinomectin. In parallel, goats were treated with subcutaneous injection of ivermectin. Then, cow, sheep, rabbit, pig, and human plasma were spiked with moxidectin. Four fractions were separated using KBr density gradient ultracentrifugation: very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and lipoprotein-deficient fraction. Cholesterol was analyzed by enzymatic assay and MLs by high-performance liquid chromatography. An average of 96% of MLs was associated with lipoproteins. The five MLs studied distributed similarly into goat plasma fractions with a preferential association with HDL (80-90%). Ivermectin partitioning in goat plasma was similar after in vitro spiking and in vivo treatment. In species displaying various lipoprotein profiles, moxidectin was also mainly associated with HDL. However, in human plasma, moxidectin was associated with a lesser extent to HDL (70%) and more to LDL (22%) when compared to other animal species. A relation between the plasma cholesterol content and pharmacokinetics of the drug is suggested. Our finding will allow further exploration of intestinal lymphatic absorption and milk elimination of these compounds-mechanisms in which lipoproteins are involved. In addition, possible improvements of new drug delivery systems are suggested.     

Synthesis,carbonic anhydrase I and II inhibition studies of the 1,3,5-trisubstituted-pyrazolines

4-(3-(4-Substituted-phenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl) benzenesulfonamides (9–16) were successfully synthesized and their chemical structures were confirmed by ¹H NMR, ¹³C NMR, and HRMS spectra. Carbonic anhydrase I and II inhibitory effects of the compounds were investigated. K_i values of the compounds were in the range of 316.7?±?9.6–533.1?±?187.8?nM towards hCA I and 412.5?±?115.4–624.6?±?168.2?nM towards hCA II isoenzymes. While K_i values of the reference compound Acetazolamide were 278.8?±?44.3?nM and 293.4?±?46.4?nM towards hCA I and hCA II izoenzymes, respectively. Compound 14 with bromine and compound 13 with fluorine substituents can be considered as the leader compounds of the series because of the lowest K_i values in series to make further detailed carbonic anhydrase inhibiton studies.     

Reductions of non-pest insects in dung of cattle treated with endectocides: a comparison of four products

Pour-on formulations of four endectocide products were compared to assess the effect of faecal residues on insects developing in naturally-colonized dung of treated cattle. In each of three independent experiments, suppression of insects was associated with application of doramectin, eprinomectin and ivermectin, but no effect was observed for moxidectin. When data were combined across experiments to increase sample sizes, suppression of insects was observed for each compound, with the least effect being observed for moxidectin. Based on the number of species affected and duration of suppression, doramectin > ivermectin > eprinomectin > moxidectin were ranked in descending order of adverse effect. A second set of three independent experiments was performed to assess the effect of endectocide treatment on dung degradation. Delayed degradation was observed for dung of cattle treated with doramectin, eprinomectin and moxidectin in the first experiment. No effect of treatment was detected in the second experiment. An effect of moxidectin was detected in the third experiment, but differences could not be detected with subsequent post-hoc tests. When data were combined across experiments to increase sample sizes, delayed degradation was detected only for eprinomectin. The apparent discrepancy between the low effect of moxidectin on insects versus its effect of dung degradation suggests the confounding action of other unidentified factors. Results of the current study indicate that use of moxidectin is least likely to affect the natural assemblage of insects associated with cattle dung.     

Carbonic anhydrase inhibitors: purification and inhibition studies of pigeon (Columba livia var. domestica) red blood cell carbonic anhydrase with sulfonamides

A carbonic anhydrase (CA, EC 4.2.1.1) from red blood cells of pigeons (Columba livia var. domestica), clCA, was purified to homogeneity. Its kinetic parameters for the CO₂ hydration reaction were measured. With a k_cat/K_m of 1.1?×?10⁸ M^?1 s^?1, and a k_cat of 1.3?×?10⁶ s^?1, clCA has a high activity, similar to that of the human isoform hCA II. A group of 25 aromatic/heterocyclic sulfonamides incorporating the sulfanilamide, homosulfanilamide, benzene-1,3-disulfonamide, and acetazolamide scaffolds showed variable inhibitory activity against the pigeon enzyme, with K_Is in the range of 1.9–3460?nM. Red blood cells of pigeons, like those of ostriches, contain thus just one CA isoform, unlike the blood of mammals, which normally contain two isoforms, one of low (CA I-like) and one of very high activity (CA II-like). However, from the sulfonamide inhibition viewpoint, the pigeon enzyme was more similar to hCA II than to the ostrich enzyme.