Adem Ergun

Synthesis and carbonic anhydrase inhibitory properties of novel coumarin derivatives

A newly series of water-soluble 1-alkyl-3-(4-methyl-7, 8-dihydroxy-2H-chromen-2-one) benzimidazolium chloride salts (3a-j) were synthesized and their inhibitory effects on the activity of purified human carbonic anhydrase (hCA) I and II were evaluated. hCA I and II from human erythrocytes were purified by a simple one step procedure by using Sepharose 4B-L-tyrosine-sulphanilamide affinity column. The result showed that all the synthesized compounds were inhibited the CA isoenzymes activity. Among them, 3g and 3j were found to be most active (IC50 = 22.09 µM and 20.33 µM) for hCA I and hCA II, respectively.

In vitro effects of some anabolic compounds on erythrocyte carbonic anhydrase I and II

The in vitro effects of the anabolic compounds, zeranol, 17 β-estradiol, diethylstilbestrol (DES), and trenbolone, on the activity of purified human carbonic anhydrase I and II were evaluated. In vitro CA enzyme activity was determined colorimetrically using the CO2 hydration method of Maren. IC50 values of the compounds that caused inhibition were determined by means of activity percentage diagrams. The IC50 concentrations of zeranol, 17 β-estradiol, DES and trenbolone on hCA I were 94, 55, 10, 898 µM and for hCA II 89, 159, 439 and 101 μM, respectively.

Synthesis and theoretical calculations of carbazole substituted chalcone urea derivatives and studies their polyphenol oxidase enzyme activity

Synthesis of carbazole substituted chalcone urea derivatives and their polyphenol oxidase enzyme activity effects on the diphenolase activity of banana tyrosinase were evaluated. Tyrosinase has been purified from banana on an affinity gel comprised of Sepharose 4B-l-tyrosine-p-aminobenzoic acid. The results showed that most of the compounds (3,4,5a,5d–h) inhibited and some of them (5c,5i–l) activated the tyrosinase enzyme activity. The molecular calculations were performed using Gaussian software for the synthesized compounds to explain the experimental results.

New coumarin derivatives as carbonic anhydrase inhibitors

Abstract In the current study, a series of 4-chloromethyl-7-hydroxy-coumarin derivatives containing imidazolium, benzimidazolium, bisbenzimidazolium and quaternary ammonium salts were synthesized, characterized and the inhibition effects of the derivatives on human carbonic anhydrases (hCA I and hCA II) were investigated as in vitro. Structures of these coumarins were confirmed by FT-IR, (1)H NMR, (13)C NMR and LC–MS analyses. Structure activity relationship study showed that 3d (IC50: 79 μM for hCA I and 88 μM for hCA II) performed higher inhibitory activity than others.

Antipsychotic agents screened as human carbonic anhydrase I and II inhibitors

Abstract The antipsychotic drugs currently used to treat schizophrenia can be divided into two distinct classes, typical and atypical antipsychotics. Many drug molecules are enzyme inhibitors that bind reversibly or irreversibly to their target through intermolecular interactions. That’s why enzyme inhibition studies are an important issue for drug design and biochemical applications. In this study, in vitro inhibition effect of some antipsychotic drugs on the purified carbonic anhydrase (CA) I and II isoenzymes were investigated by using CO2 as a substrate. CA I and II were purified from human erythrocytes by a simple one step procedure using Sepharose 4B-L-tyrosine-sulfonamide affinity column. The results showed that all the drugs inhibited the cytosolic carbonic anhydrases enzyme activity in a concentration-dependent fashion. Among the studied drugs, aripiprazole and pramipexole were found to be the most active one for hCA I (IC50: 3.64 and 5.37 μM) and hCA II (IC50: 4.16 and 4.81 μM) activity, respectively.

Synthesis, antioxidant and carbonic anhydrase I and II inhibitory activities of novel sulphonamide-substituted coumarylthiazole derivatives

Abstract New secondary benzenesulphonamide-substituted coumarylthiazole derivatives were synthesized and their inhibitory effects on purified carbonic anhydrase I and II were evaluated using CO2 as a substrate. The result showed that all the synthesized compounds exhibited inhibitory activity on both hCA I and hCA II with N-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)naphthalene-2-sulphonamide (5f, IC50 value of 5.63 and 8.48 µM, against hCA I and hCA II, respectively) as the strongest inhibitor revealed from this study. Structure–activity relationship revealed that the inhibitory activity of the synthesized compounds is related to the type of the halogen and bulky substituent on the phenyl ring. In addition, the cupric reducing antioxidant capacities (CUPRAC) and ABTS cation radical scavenging abilities of the synthesized compounds were assayed. 4-methoxy-N-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)benzenesulphonamide (5e) exhibited the strongest ABTS and CUPRAC activity with IC50 value of 48.83 µM and A0.50 value of 23.29 µM, respectively.

In vitro inhibition effects on erythrocyte carbonic anhydrase I and II and structure-activity relationships of cumarylthiazole derivatives

Coumarin and heterocyclic compounds incorporating urea have clinical applications as antiepileptics, diuretics, and antiglaucoma agents due to their carbonic anhydrase inhibitory properties. We investigated inhibition of carbonic anhydrase I and II with a series of coumarylthiazole derivatives containing urea/thiourea groups. All the investigated compounds exhibited inhibitory activity on both hCA I and hCA II, with 1-(3-chlorophenyl)-3-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)urea being the strongest inhibitor. Structure–activity relationship study showed that most of urea derivatives were more inhibiting for hCA I and hCA II than thiourea derivatives. The electron-withdrawing groups at the phenyl ring increased the inhibitory activity compared to electron-donating groups.

In vitro effects of estrogen and progesterone containing drugs on human erythrocyte carbonic anhydrase I and II isozymes in women smokers and nonsmokers

Background Carbonic anhydrases (CAs), a group of metalloenzymes, are involved in numerous physiological and pathological processes such as acid–base balance, gluconeogenesis, lipogenesis, ureagenesis, electrolyte secretion in various tissues, bone resorption and calcification, and tumorigenicity. In the current study, we aimed to determine and compare possible alterations in the activity of carbonic anhydrase I (CA I) and carbonic anhydrase II (CA II) isozymes by using estrogens and progestagens in female smokers and nonsmokers. Methods Blood samples from 30 smoker and 30 nonsmoker volunteers were drawn after obtaining informed consent. The blood samples were centrifuged to separate the plasma and erythrocytes. Thereafter, hemolysate was prepared from the red cells. CA I and CA II were purified from human erythrocytes with a simple one‐step procedure using Sepharose 4B‐l‐tyrosine‐sulfonamide affinity column. CAI and CA II isozymes were treated with estrogen and progesterone‐containing drugs, after which the inhibition or activation of the enzyme was determined. Results CA I and CA II enzyme activity was observed to be increased in female smokers. The results of this study show that dienogest is the most effective inhibitor for human erythrocytes CA I when compared with micronized progesterone, hydroxyprogesterone caproate, estradiol valerate, and estradiol hemihydrate in both female smokers and nonsmokers. All active ingredients have been shown to have a stronger inhibition in smokers than nonsmokers for CA I activity. Additionally, estradiol valerate and hydroxyprogesterone caproate have stronger inhibition against CA II enzyme activity in women who smoke. Conclusion The results of the current study provide important information to clinicians about how to consider the possible adverse effects of these drugs which are produced as a result of inhibition of CA I and CA II enzyme. Clinicians should take into consideration the side effects caused by CA I and CA II enzyme inhibition when prescribing these drugs in the treatment of different clinical conditions, especially in women who smoke.

Synthesis and evaluation of N-heteroarylsubstituted triazolosulfonamides as carbonic anhydrase inhibitors

Abstract A new series of N-heteroarylsubstituted triazolosulfonamide compounds were synthesized and their inhibitory effects on the activity of purified human carbonic anhydrase (hCA) I and II were evaluated. Compounds (3 a–k) were prepared by propargylation of N-heteroaryl compounds. Compound 5 was obtained from sulfanilamide and sodium nitrite followed by addition of sodium azide. The products (6 a–k) were synthesized from compounds 3 and 5. The results showed that all the synthesized compounds were inhibited the CA isoenzymes activity. Figure 6a (IC50 = 0.52 µM for hCA I and 0.34 µM for hCA II) has the most inhibitory effect among the synthesized compounds.

Synthesis and carbonic anhydrase inhibitory properties of new spiroindoline-substituted sulphonamide compounds

Abstract New spiroindoline-substituted sulphonamide compounds were synthesised and their inhibitory effects on the activity of purified human carbonic anhydrase I and II were evaluated. Human carbonic anhydrase isoenzymes (hCA-I and hCA-II) were purified from erythrocyte cells by affinity chromatography. The inhibitory effects of the 14 synthesised sulphonamides (6a–n) on esterase activities of these isoenzymes were studied in vitro. In relation to these activities, the inhibition equilibrium constants (Ki) were determined. The results showed that all the synthesised compounds inhibited the carbonic anhydrase (CA) isoenzyme activity. Among them, 6b was found to be the most active (Ki: 0.042 μM) for hCA I and 6a (Ki: 0.151 μM) for hCA II.