Synthesis and evaluation of N-substituted indole-3-carboxamide derivatives as inhibitors of lipid peroxidation and superoxide anion formation

The in vitro antioxidant effects of novel N-substituted indole-3-carboxamides (I3CDs) 1-10 on rat liver microsomal NADPH-dependent lipid peroxidation (LP) levels and their free radicals scavenging properties were determined by the inhibition of superoxide anion formation (SOD). Among the synthesized compounds, 4, 5, 8 and 9 significantly inhibited SOD with an inhibition range at 84–100% at 10^{? 3} M concentration. The presence of halo substituents both ortho- and para- positions of these compounds resulted 100% inhibition of SOD. Comparison the activity results of halogenated and non-halogenated derivatives suggested that the halogenated compounds are more active than the non-halogenated compounds. On the other hand, the introduction of a para fluoro benzyl in the 1-position of indole (compounds 7, 8) has more impact on the SOD inhibition when the benzamide ring was mono halogenated. However, none of other compounds had a significant inhibitory effects on the level of lipid peroxidation.     

Synthesis of N-substituted indole-2-carboxamides and investigation of their biochemical responses against free radicals

The antioxidant role of novel N-substituted indole-2-carboxamides (I2CDs) was investigated for their inhibitory effects on superoxide anion (O₂^? ) and lipid peroxidation (LP). Among the synthesized I2CDs, 3, 4, 6, 8 and 9 significantly inhibited O₂^{· ?} with an inhibition range at 70–98%. Examination of substituent effects on activity showed that both the ortho- and para-positions of the benzamide residue needs to be dichlorinated in order to get a maximum inhibitory effect on superoxide anion. In general, halogenated derivatives were found more active then the non-halogenated ones. However, none of the I2CDs had a significant inhibitory effects on the level of lipid peroxidation; only compounds 7 and 10 moderately decreased LP levels by over 50% at 10^{? 3} M concentrations.     

Synthesis of some 4-arylidenamino-4H-1,2,4-triazole-3-thiols and their antituberculosis activity

The increasing clinical importance of drug-resistant mycobacterial pathogens has lent additional urgency to microbiological research and new antimycobacterial compound development. For this purpose, new triazoles were synthesized and evaluated for antituberculosis activity. A series of 4-arylidenamino-4H-1,2,4-triazole-3-thiol derivatives (2a–n) were synthesized from the treatment of 4-amino-4H-1,2,4-triazoles-3-thiol (1) with the respective aldehydes and were evaluated for antituberculosis activity against Mycobacterium tuberculosis H₃₇Rv (ATCC 27294), using the BACTEC 460 radiometric system and BACTEC 12B medium. Compound 2k showed an intereting activity at 6.25 μg/mL with a 87 percentage inhibition.     

Screening and evaluation of antioxidant activity of some amido-carbonyl oxime derivatives and their radical scavenging activities

The antioxidant activity of some amido-carbonyl oximes containing a C=O and –NH–R adjacent to the oxime group, [Phenyl-C(=O)-C(=N-OH)-N(-H)-Phenyl(-R)] where R= H, 4-chloro, 4-methyl, 4-methoxy, 3,4-dichloro, 3,4-dimethyl, 3-chloro-4-dimethyl, 3-chloro-4-methoxy, naphthyl and an amido-carbonyl dioxime were investigated in vitro by ferric thiocyanate, total reducing power by potassium ferricyanide reduction, 1,1-diphenyl-2- picryl-hydrazyl (DPPH^·) free radical scavenging, ferrous ions chelating, superoxide anion radical scavenging and hydrogen peroxide scavenging activity assays. The results indicated that the amido-carbonyl oximes have powerful antioxidant capacity.     

In Vivo and In Vitro Effects of Some Plant Hormones on Rat Erythrocyte Carbonic Anhydrase and Glucose-6-Phosphate Dehydrogenase Activities

The present study was undertaken to determine in vivo and in vitro effects of some plant growth regulators on rat erythrocyte carbonic anhydrase (CA) and glucose-6-phosphate dehydrogenase (G6PD) activities. Both in vivo and in vitro, spermidine and kinetin did not affect enzymatic activities of CA and G6PD, whereas putrescine decreased these activities, and abscisic acid increased them. Since plants use such growth regulators, their effects should be considered on mammals consuming them since they may possess important biological effects.     

Curcumin prevents liver fat accumulation and serum fetuin-A increase in rats fed a high-fat diet

Fetuin-A is synthesized in the liver and is secreted into the bloodstream. Clinical studies suggest involvement of fetuin-A in metabolic disorders such as visceral obesity, insulin resistance, diabetes, and fatty liver. Curcumin is extracted from the rhizome Curcuma longa and has been shown to possess potent antioxidant, anticarcinogenic, anti-inflammatory, and hypoglycemic properties. In this study, we investigated the effect of curcumin treatment on serum fetuin-A levels as well as hepatic lipids and prooxidant–antioxidant status in rats fed a high-fat diet (HFD). Male Sprague–Dawley rats were divided into six groups. Group 1 was fed control diet (10 % of total calories from fat). Groups 2 and 3 were given curcumin (100 and 400 mg/kg bw/day, respectively ) by gavage for 8 weeks and were fed control diet. Group 4 was fed with HFD (60 % of total calories from fat). Groups 5 and 6 received HFD together with the two doses of curcumin, respectively. Curcumin treatment appeared to be effective in reducing liver triglycerides and serum fetuin-A levels. These findings suggest that the reduction of fetuin-A may contribute to the beneficial effects of curcumin in the pathogenesis of obesity.     

Chlamydia pneumoniae infection acts as an endothelial stressor with the potential to initiate the earliest heat shock protein 60-dependent inflammatory stage of atherosclerosis

We identified increased expression and redistribution of the intracellular protein 60-kDa human heat shock protein (hHSP60) (HSPD1) to the cell surface in human endothelial cells subjected to classical atherosclerosis risk factors and subsequent immunologic cross-reactivity against this highly conserved molecule, as key events occurring early in the process of atherosclerosis. The present study aimed at investigating the role of infectious pathogens as stress factors for vascular endothelial cells and, as such, contributors to early atherosclerotic lesion formation. Using primary donor-matched arterial and venous human endothelial cells, we show that infection with Chlamydia pneumoniae leads to marked upregulation and surface expression of hHSP60 and adhesion molecules. Moreover, we provide evidence for an increased susceptibility of arterial endothelial cells for redistribution of hHSP60 to the cellular membrane in response to C. pneumoniae infection as compared to autologous venous endothelial cells. We also show that oxidative stress has a central role to play in endothelial cell activation in response to chlamydial infection. These data provide evidence for a role of C. pneumoniae as a potent primary endothelial stressor for arterial endothelial cells leading to enrichment of hHSP60 on the cellular membrane and, as such, a potential initiator of atherosclerosis.     

Quantum chemical investigation of the intra- and intermolecular proton transfer reactions and hydrogen bonding interactions in 4-amino-5-(2-hydroxyphenyl)-2H-1,2,4-triazole-3(4H)-thione

The intramolecular thione-thiol tautomerism and intermolecular double proton transfer reaction of the hydrogen-bonded thione and thiol dimers in the title triazole compound were studied at the B3LYP level of theory using 6?311++G(d,p) basis function. The influence of the solvent on the single and double proton transfer reactions was examined in three solvents (chloroform, methanol and water) using the polarizable continuum model (PCM) approximation. The computational results show that the thione tautomer is the most stable isomer with a very high tautomeric energy barrier both in the gas phase and in solution phase, indicating a quite disfavored process. The solvent effect is found to be sizable with increasing polarity. In the double proton transfer reaction, the thione dimer is found to be more stable than thiol dimer both in the gas phase and in solution phase. The energetic and thermodynamic parameters of the double proton transfer process show that the double proton exchange from thione dimer to thiol dimer is thermodynamically unfavored. However, the exchange from thiol dimer to thione dimer for the gas phase and water phase seems to be feasible with a low barrier height and with a negative value in enthalpy and free energy changes. In addition, the hydrogen bonding interactions were analyzed in the gas phase regarding their geometries and energies. It is found that all complex formations are enthalpically favored, and the stability of the H-bonds comes in the order of S1—H2···N2 > N2—H2···S1 > N3—H3B···O1. Finally, non-linear optical properties were carried out at the same calculation level in the gas phase.

Electricity generation from young landfill leachate in a microbial fuel cell with a new electrode material

This study aims at evaluating the performance of a two-chambered continuously fed microbial fuel cell with new Ti–TiO₂ electrodes for bioelectricity generation from young landfill leachate at varying strength of wastewater (1–50 COD g/L) and hydraulic retention time (HRT, 0.25–2 days). The COD removal efficiency in the MFC increased with time and reached 45 % at full-strength leachate (50 g/L COD) feeding. The current generation increased with increasing leachate strength and decreasing HRT up to organic loading rate of 100 g COD/L/day. The maximum current density throughout the study was 11 A/m² at HRT of 0.5 day and organic loading rate of 67 g COD/L/day. Coulombic efficiency (CE) decreased from 57 % at feed COD concentration of 1 g/L to less than 1 % when feed COD concentration was 50 g/L. Increase in OLR resulted in increase in power output but decrease in CE.