Synthesis and carbonic anhydrase I, II, IV and XII inhibitory properties of N-protected amino acid – sulfonamide conjugates

N-protected amino acids (Gly, Ala and Phe protected with Boc and Z groups) were reacted with sulfonamide derivatives, leading to the corresponding N-protected amino acid-sulfonamide conjugates. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against four human (h) isoforms, hCA I, hCA II, hCA IV and hCA XII. Among them, hCA II, IV and XII are antiglaucoma drug targets, being involved in aqueous humor secretion within the eye. Low nanomolar inhibition was measured against all four isoforms with the 20 reported sulfonamides, but no selective inhibitory profiles, except for some CA XII-selective derivatives, were observed. hCA I, II and XII were generally better inhibited by sulfonamides incorporating longer scaffolds and Gly/Ala, whereas the best hCA IV inhibitors were homosulfanilamide derivatives, incorporating Phe moieties. The amino acid-sulfonamide conjugates show good water solubility and effective hCA II, IV and XII inhibition, and may be considered as interesting candidates for antiglaucoma studies

Synthesis and carbonic anhydrase inhibitory properties of amino acid – coumarin/quinolinone conjugates incorporating glycine, alanine and phenylalanine moieties

N-Protected amino acids (Gly, Ala and Phe) were reacted with amino substituted coumarin and quinolinone derivatives, leading to the corresponding N-protected amino acid-coumarin/quinolinone conjugates. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against various human (h) isoforms, such as hCA I, hCA II, hCA IV and hCA XII. The quinolinone conjugates were inactive as enzyme inhibitors, whereas the coumarins were ineffective hCA I/II inhibitors (KIs > 50 μM) but were submicromolar hCA IV and XII inhibitors, with inhibition constants ranging between 92 nM and 1.19 μM for hCA IV, and between 0.11 and 0.79 μM for hCA XII. These coumarin derivatives, as many others reported earlier, thus show an interesting selective inhibitory profile for the membrane-bound over the cytosolic CA isoforms

Determination of minerals and trace elements in soils and the relation with its concentrations in sugar beets

Twelve sugar beets and corresponding soil samples from the plantation near Malatya, Turkey were analyzed for mineral and trace element contents. Thirteen metals (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se and Zn) were selected and analyzed quantitatively by FAAS/FAES and ETAAS. Principal component analysis and hierarchical cluster analysis were used to explore samples based on the element contents. The principal component analysis analysis of sugar beet samples yielded five principal components which were able to explain about 84% of the total variance in the data set. The number of principal components that are higher than one was four for the soil samples and were able to explain 83% of total variance. Hierarchical cluster analysis of sugar beet samples and corresponding soil samples resulted in two main clusters based on the geographic regions of the samples. In terms of the elements being analyzed, the hierarchical cluster analysis method resulted in 3-4 clusters of the elements in both sugar beet and soil samples

Synthesis and human carbonic anhydrase I, II, VA, and XII inhibition with novel amino acid–sulphonamide conjugates

A series of amino acid–sulphonamide conjugates was prepared through benzotriazole mediated coupling reactions and characterised by 1H-NMR, 13C-NMR, MS, and FTIR spectroscopic techniques as well as elemental analysis. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was determined against four human (h) isoforms, hCA I, hCA II, hCA VA, and hCA XII. Most of the synthesised compounds showed effective in vitro CA inhibitory properties. The new amino acid–sulphonamide conjugates showed potent inhibitory activity against hCA II, some of them at subnanomolar levels, exhibiting more effective inhibitory activity compared to the standard drug acetazolamide. Some of these sulphonamides were also found to be effective inhibitors of hCA I, hCA VA, and hCA XII, with activity from the low to high nanomolar range

Synthesis carbonic anhydrase enzyme inhibition and antioxidant activity of novel benzothiazole derivatives incorporating glycine, methionine, alanine, and phenylalanine moieties

Thirteen novel benzothiazole derivatives incorporating glycine, methionine, alanine, and phenylalanine were synthesised by facile acylation reactions through benzotriazole or DCC mediated reactions and their structures were identified by 1H-NMR, 13C-NMR, and FT-IR spectroscopic techniques and elemental analysis. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against four human (h) isoforms, hCA I, hCA II, hCA V, and hCA XIII. Some of the synthesised compounds showed good in vitro carbonic anhydrase inhibitory properties, with inhibition constants in the micromolar level. The new amino acid benzothiazole conjugates found to be more effective against hCA V and hCA II inhibition. In vitro antioxidant activities of the novel compounds were determined by DPPH method. Most of the synthesised compounds showed moderate to low antioxidant activities compared to the control antioxidant compounds (BHA and α-tocopherol)

Synthesis and carbonic anhydrase inhibitory properties of amino acid – coumarin/quinolinone conjugates incorporating glycine, alanine and phenylalanine moieties

N-Protected amino acids (Gly, Ala and Phe) were reacted with amino substituted coumarin and quinolinone derivatives, leading to the corresponding N-protected amino acid-coumarin/quinolinone conjugates. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against various human (h) isoforms, such as hCA I, hCA II, hCA IV and hCA XII. The quinolinone conjugates were inactive as enzyme inhibitors, whereas the coumarins were ineffective hCA I/II inhibitors (KIs > 50 μM) but were submicromolar hCA IV and XII inhibitors, with inhibition constants ranging between 92 nM and 1.19 μM for hCA IV, and between 0.11 and 0.79 μM for hCA XII. These coumarin derivatives, as many others reported earlier, thus show an interesting selective inhibitory profile for the membrane-bound over the cytosolic CA isoforms

Dichlorobis[1-(2-ethoxyethyl)-1H-benzimidazole-?3] cobalt(II)

The title compound, [CoCl2(C11H14N 2O)2], was synthesized from 1-(2-ethoxyethyl)benzimidazole and cobalt dichloride in ethanol. The CoII atom is coordinated in a distorted tetrahedral environment by two Cl atoms and two N atoms. The crystal structure is stabilized by intermolecular C - H?Cl and C - H?O interactions. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved

Determination of minerals and trace elements in soils and the relation with its concentrations in sugar beets

Twelve sugar beets and corresponding soil samples from the plantation near Malatya, Turkey were analyzed for mineral and trace element contents. Thirteen metals (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se and Zn) were selected and analyzed quantitatively by FAAS/FAES and ETAAS. Principal component analysis and hierarchical cluster analysis were used to explore samples based on the element contents. The principal component analysis analysis of sugar beet samples yielded five principal components which were able to explain about 84% of the total variance in the data set. The number of principal components that are higher than one was four for the soil samples and were able to explain 83% of total variance. Hierarchical cluster analysis of sugar beet samples and corresponding soil samples resulted in two main clusters based on the geographic regions of the samples. In terms of the elements being analyzed, the hierarchical cluster analysis method resulted in 3-4 clusters of the elements in both sugar beet and soil samples

Preparation, carbonic anhydrase enzyme inhibition and antioxidant activity of novel 7-amino-3,4-dihydroquinolin-2(1H)-one derivatives incorporating mono or dipeptide moiety

New dipeptide–dihydroquinolinone derivatives were successfully synthesised by benzotriazole mediated nucleophilic acyl substitution reaction and their structures were elucidated by spectroscopic and analytic techniques. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was determined against four human (h) isoforms, hCA I, hCA II, hCA IX and hCA XII. While all compounds showed moderate to good in vitro CA inhibitory properties against hCA IX and hCA XII with inhibition constants in the micromolar level (37.7–86.8 and 2.0–8.6 µM, respectively), they did not show inhibitory activity against hCA I and hCA II up to 100 µM concentration. The antioxidant capacity of the peptide–dihydroquinolinone conjugates was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. Most of the synthesised compounds showed low antioxidant activities compared to the control antioxidant compounds BHA and α-tocopherol