The effect of ethanol on erythrocyte carbonic anhydrase isoenzymes activity: an in vitro and in vivo study

The ethanol is a widely consumed as sedative-hypnotic drug throughout the world. In this study, the effects of ethanol were investigated on carbonic anhydrase (CA) enzyme activities both in vitro in human erythrocyte and in vivo in Sprague-Dawley rat erythrocyte. For in vitro study, the human carbonic anhydrase-I (HCA-I) and -II (HCA-II) are purified by Sepharose 4B-L-tyrosine-sulphanilamide affinity chromatography. In vivo CA enzyme activity was determined colorimetrically by using CO(2)-hydration method of Wilbur and Anderson. Rat blood samples were taken from each rat before and after the ethanol administration at different times (1 h, 3 h, and 5 h). Rat erythrocyte CA activity was significantly inhibited by pharmacological dosage of the ethanol (2 mL.kg(- 1)) for up to 3 h (p < 0.001) following intraperitoneally administration. The ethanol showed in vitro inhibitory effects on HCA-I and HCA-II hydratase activity, determined by colorimetrically using the CO(2)-hydratase method. The inhibitor concentrations causing up to 50% inhibition (IC(50)) were 2.09 M for HCA-I (r(2):0.9273) and 1.83 M for HCA-II (r(2):9749). In conclusion, it was demonstrated that carbonic anhydrase enzyme in erythrocytes was significantly inhibited by the ethanol both in in vitro and in vivo.     

Microwave-assisted synthesis and bioevaluation of new sulfonamides

In this study, 4-[5-(4-hydroxyphenyl)-3-aryl-4,5-dihydro-1H-pyrazol-1-yl]benzenesulfonamide derivatives (8-14) were synthesized for the first time by microwave irradiation and their chemical structures were confirmed by ¹H NMR, ¹³C NMR and HRMS. Cytotoxic activities and inhibitory effects on carbonic anhydrase I and II isoenzymes of the compounds were investigated. The compounds 9 (PSE?=?4.2), 12 (PSE?=?4.1) and 13 (PSE?=?3.9) with the highest potency selectivity expression (PSE) values in cytotoxicity experiments and the compounds 13 (Ki?=?3.73?±?0.91?nM toward hCA I) and 14 (Ki?=?3.85?±?0.57?nM toward hCA II) with the lowest Ki values in CA inhibition studies can be considered as leader compounds for further studies.     

In vitro prooxidant effect of caffeine

Caffeine is a methylxanthine compound that acts as a stimulant in humans. It is the most widely consumed behaviourally active substance in the western world and it affects calcium influx and release in living cells. Caffeine is present in various substances such as tea, coffee and some medications. This article is focused on the impact of caffeine on oxidation. Caffeine promoted the peroxidation of linoleic acid emulsions used by 32.5, 48.9, and 54.3%, respectively, at 15, 30 and 45 microg/mL concentrations. Standard antioxidants such as alpha-tocopherol and trolox, a water-soluble analogue of tocopherol, inhibited 76.2 and 93.2% peroxidation of linoleic acid emulsion at 45 microg/mL concentration. Also, PC(50) value (caffeine concentration that produced a 50% increase in linoleic acid peroxidation) of caffeine was found to be 185 microM.     

Effects of low molecular weight plasma inhibitors of rainbow trout (Oncorhynchus mykiss) on human erythrocyte carbonic anhydrase-II isozyme activity in vitro and rat erythrocytes in vivo

The effects of low molecular weight plasma inhibitors from rainbow trout (Oncorhynchus mykiss) (RT) were investigated on the carbonic anhydrase enzyme (CA) activities in in vitro human and in in vivo Sprague-Dawley rat erythrocytes. The RT blood was used as extracellular fluid (plasma) source and plasma inhibitors were obtained by dialysis of the plasma. For the in vitro study, human carbonic anhydrase-II (HCA-II) isozyme was obtained by Sepharose 4B-L-tyrosine-sulfanylamide affinity chromatography with an overall purification of about 646-fold. The enzyme (specific activity of 7750 EU/mg protein) was obtained with a yield of 71.1% and SDS-PAGE showed a single band. From in vitro studies, the I50 value for RT plasma inhibitors obtained was 0.37 mg/ml. From in vivo studies on rat erythrocytes, CA activity was significantly inhibited by the inhibitors from the extracellular fluid of RT for up to 3 h (p < 0.05) following intraperitoneal administration.     

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.     

Inhibitory effects of isatin Mannich bases on carbonic anhydrases,acetylcholinesterase, and butyrylcholinesterase

The effects of isatin Mannich bases incorporating (1-[piperidin-1-yl (P1)/morpholin-4-yl (P2)/N-methylpiperazin-1-yl (P3)]methyl)-1H-indole-2,3-dione) moieties against human (h) carbonic anhydrase (CA, EC 4.2.1.1) isoenzymes hCA I and hCA II, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes were evaluated. P1–P3 demonstrated impressive inhibition profiles against AChE and BChE and also inhibited both CAs at nanomolar level. These inhibitory effects were more powerful in all cases than the reference compounds used for all these enzymes. This study suggests that isatin Mannich bases P1–P3 are good candidate compounds especially for the development of new cholinesterase inhibitors since they were 2.2–5.9 times better inhibitors than clinically used drug Tacrine.     

Lymphocyte subpopulations in pulmonary tuberculosis patients

Protection against Mycobacterium tuberculosis is based on cell-mediated immunity, most importantly involving CD4(+) and CD8(+) T-cell subsets. The aim of this study was to evaluate CD4(+) and CD8(+) T-cell profiles and CD19(+) and CD3(+)CD(16 + 56)(+) populations in patients with pulmonary tuberculosis. CD4(+) and CD8(+) T cells, B-lymphocytes, and natural killer (NK) cells were evaluated in 75 active (APTB) and 25 inactive (IPTB) pulmonary tuberculosis cases and 20 healthy subjects (HCs). The results were compared at different stages of antituberculosis treatment in the APTB patients and also according to X-ray findings in the newly diagnosed APTB patients. The percentages of CD4(+) T cells were significantly lower (P < .01) and those of CD3(+)CD(16+56)(+) cells were significantly higher (P < .01) in APTB patients than in HCs. CD8(+) T cells were significantly decreased (P < .05), and CD3(-)CD(16+56)(+) cells were significantly increased (P < .01), in IPTB patients compared to HCs. The percentages of CD4(+), CD8(+), CD3(-)CD19(+), and CD3(-)CD(16+56)(+) cells showed no differences at different times of the antituberculosis regimen, and different stages of newly diagnosed APTB patients. APTB patients have a reduced percentage of circulating CD4(+) T cells and an increased percentage of NK cells compared with healthy individuals. These cells could play important roles in the immune response to M tuberculosis infection.     

Synthesis of some novel pyridine compounds containing bis‐1,2,4‐triazole/thiosemicarbazide moiety and investigation of their antioxidant properties,carbonic anhydrase,and acetylcholinesterase enzymes inhibition profiles

Some novel derivatives of thiosemicarbazide and 1,2,4‐triazole‐3‐thiol were synthesized and evaluated for their biological activities. The title compounds were prepared starting from readily available pyridine‐2,5‐dicarboxylic acid. The reaction carboxylic acid with absolute ethanol afforded the corresponding dimethyl pyridine‐2,5‐dicarboxylate ( 1 ). The reaction of dimethyl‐2,5‐pyridinedicarboxylate ( 1 ) with hydrazine hydrate good yielded pyridine‐2,5‐dicarbohydrazide ( 2 ). Refluxing compound 2 with alkyl/aryl isothiocyanate derivatives for 3–8 h afforded 1,4‐disubstituted thiosemicarbazides ( 3a–e ). Base‐catalyzed intra‐molecular dehydrative cyclization of these intermediates furnished the 4,5‐disubstituted bis‐mercaptotriazoles ( 4a–e ) in good yield (85%–95%). Among the target compounds, 2,2′‐(pyridine‐2,5‐diyldicarbonyl)bis[N‐(p‐methoxyphenyl)hydrazinecarbothioamide] ( 3c ) showed very high activity with value of 72.93% against 1,1‐diphenyl‐2‐picrylhydrazyl free radical at the concentration of 25 μg/mL. The inhibitory effects of the target compounds against acetylcholinesterase (AChE), hCA I, and II were studied. AChE, cytosolic hCA I and II isoforms were potently inhibited by synthesized these derivatives with K_is in the range of 3.07 ± 0.76–87.26 ± 29.25 nM against AChE, in the range of 1.47 ± 0.37–10.06 ± 2.96 nM against hCA I, and in the range of 3.55 ± 0.57–7.66 ± 2.06 nM against hCA II, respectively.