Antioxidant activity of β-carboline derivatives

The investigated β-carboline derivatives were synthesized to elucidate their activity as 5-HT1A and 5- HT2A receptor ligands. Compounds containing a carboline ring system belong to a large family of biological active indoles, which are very important for the function of the central nervous system (1). The research was carried out to determine antioxidative or oxidative properties of these derivatives. Analysis of antioxidative capacity as indication of oxidative stress was based on ability to scavenge free radicals by DPPH (free radical scavenging activity test) and FRAP test (2, 3). The results were compared to those of standard substances like vitamin C, trolox, quercetin and curcumin. The research of derivatives of β-carboline shows antioxidative activity comparable to vitamin C. Compounds 1, 5 and 6, but only in low concentration, have antioxidative activity. Substance 10 was classified as that with prooxidative activity

Modification of niobium surfaces using plasma electrolytic oxidation in silicate solutions

Herein, a study of the plasma electrolytic oxidation (PEO) of niobium in an anodising bath composed of potassium silicate (K2SiO3) and potassium hydroxide (KOH) is reported. The effects of the K2SiO3 concentration in the bath and the process voltage on the characteristics of the obtained oxide layers were assessed. Compact, barrier-type oxide layers were obtained when the process voltage did not exceed the breakdown potential of the oxide layer. When this threshold was breached, the morphology of the oxide layer changed markedly, which is typical of PEO. A significant amount of silicon, in the form of amorphous silica, was incorporated into the oxide coatings under these conditions compared with the amount obtained with conventional anodising. This surface modification technique led to an improvement in the corrosion resistance of niobium in Ringer’s solution, regardless of the imposed process conditions

Potentiation of adipogenesis and insulinomimetic effects of novel vanadium complex (N'-[(E)-(5-bromo-2-oxophenyl)methylidene]-4-methoxybenzohydrazide)oxido(1,10-phenanthroline)vanadium(IV) in 3T3-L1 cells

Recent research on the action of vanadium compounds shows its important effect on adipogenesis processes and adipocyte function. On the basis of previous screening tests in cellular models, the novel vanadium complex (N′-[(E)-(5-bromo-2-oxophenyl)methylidene]4-methoxybenzohydrazide)oxido(1,10-phenanthroline)vanadium(IV) was selected for this study. This complex exhibits potent inhibition of tyrosine phosphatases, and differences in the degree of inhibition were observed particularly for phosphatases. A significant increase in intracellular lipid accumulation and proliferative effect on 3T3-L1 preadipocytes confirmed the ability of this complex to enhance adipogenesis. The insulinomimetic activity of the tested complex was also demonstrated in fully differentiated 3T3-L1 adipocytes, in which glucose utilization was potentiated. The obtained results support the hypothesis that vanadium complexes show promising possibilities for use as new therapeutic strategies for the treatment of type 2 diabetes

Evaluation of antiplatelet activity of novel guanidine derivatives in the aspects of their adrenergic receptor activity

Designed acetamide derivatives based on guanidine and various heteroaryl carboxylic acids, were preliminary in vitro study of their adrenergic receptor affinity and anti-plateled effects. The obtained results have showed that exchange of 2,6-dichloro-phenyl substituent of guanidine into heteroaryl moieties, caused the decrease of receptor affinity, especially for α1-adrenoceptors. The observed receptor profile of activity for α2BAR was not changed compared to α1-ARs. Moreover, the observed effects on platelet aggregation induced by sub-threshold concentration of collagen and adrenaline strongly suggested that antiaggregant effect of N- (diaminomethylene)-2-(pyridin-3-yl)acetamide and N-(diaminomethylene)-2-(pyridin-4-yl)acetamide depends on their α2B-ARs antagonistic activity

Tridentate hydrazido-hydrazones vanadium complexes : synthesis, properties and biological activity

Nine new vanadium complexes, with tridentate Schiff base ligand based on 3,5-di-tertbutyl-2-hydroxybenzaldehyde and different hydrazides, are described and characterized. The X-ray crystal structure of complex 8 shows distorted octahedral geometry of vanadium, with ONO ligand in equatorial position. The tridentate Schiff base ligand forms six membered and five-membered chelate rings at the V(V) acceptor center, with the corresponding bite angles being 82.97(9)˚ and 74.48(9)˚. The molecules are gathered by means of intermolecular OH...N hydrogen bond and layered by π...π interactions involving the pyridine and phenolate rings. Such interactions expand the structure along the crystallographic a axis. The complexes were characterized by the elemental analyses, IR, UV-Vis, EPR spectroscopy, cyclic voltammetry, thermogravimetry and magnetic susceptibility measurements. The stabilization role of co-ligands is discussed. The cytotoxicity versus HepG2 hepatocytes and inhibition of human recombinant PTP1B was studied

A comparison of the anorectic effect and safety of the alpha_{2}-adrenoceptor ligands guanfacine and yohimbine in rats with diet-induced obesity

The search for drugs with anorectic activity, acting within the adrenergic system has attracted the interest of researchers. Partial α2-adrenoceptor agonists might offer the potential for effective and safe treatment of obesity. We compared the effectiveness and safety of α2-adrenoceptor ligands in reducing body mass. We also analyzed if antagonist and partial agonists of α2-adrenoceptor--yohimbine and guanfacine--act similarly, and determined which course of action is connected with anorectic activity. We tested intrinsic activity and effect on the lipolysis of these compounds in cell cultures, evaluated their effect on meal size, body weight in Wistar rats with high-fat diet-induced obesity, and determined their effect on blood pressure, heart rate, lipid profile, spontaneous locomotor activity, core temperature and glucose, as well as glycerol and cortisol levels. Both guanfacine and yohimbine showed anorectic activity. Guanfacine was much more effective than yohimbine. Both significantly reduced the amount of intraperitoneal adipose tissue and had a beneficial effect on lipid profiles. Decreased response of α2A-adrenoceptors and partial stimulation of α2B-receptors seem to be responsible for the anorectic action of guanfacine. The stimulation of α1-adrenoceptors by guanfacine is responsible for cardiovascular side effects but may also be linked with improved anorexic effect. α1-adrenoceptor blockade is connected with the side effects of yohimbine, but it is also associated with the improvement of lipid profiles. Guanfacine has been approved by the Food and Drug Administration (FDA) to treat hypertension and conduct disorder, but as it reduces body weight, it is worth examining its effectiveness and safety in models of obesity

Antidepressant- and anxiolytic-like effects of new dual 5-HT_{1A} and 5-HT_{7} antagonists in animal models

The aim of this study was to further characterize pharmacological properties of two phenylpiperazine derivatives: 1-{2-[2-(2,6-dimethlphenoxy)ethoxy]ethyl}-4-(2-methoxyphenyl)piperazynine hydrochloride (HBK-14) and 2-[2-(2-chloro-6-methylphenoxy)ethoxy]ethyl-4-(2- methoxyphenyl)piperazynine dihydrochloride (HBK-15) in radioligand binding and functional in vitro assays as well as in vivo models. Antidepressant-like properties were investigated in the forced swim test (FST) in mice and rats. Anxiolytic-like activity was evaluated in the four-plate test in mice and elevated plus maze test (EPM) in rats. Imipramine and escitalopram were used as reference drugs in the FST, and diazepam was used as a standard anxiolytic drug in animal models of anxiety. Our results indicate that HBK-14 and HBK-15 possess high or moderate affinity for serotonergic 5-HT2, adrenergic α1, and dopaminergic D2 receptors as well as being full 5-HT1A and 5-HT7 receptor antagonists. We also present their potent antidepressant-like activity (HBK-14-FST mice: 2.5 and 5 mg/kg; FST rats: 5 mg/kg) and (HBK-15-FST mice: 1.25, 2.5 and 5 mg/kg; FST rats: 1.25 and 2.5 mg/kg). We show that HBK-14 (four-plate test: 2.5 and 5 mg/kg; EPM: 2.5 mg/kg) and HBK-15 (four-plate test: 2.5 and 5 mg/kg; EPM: 5 mg/kg) possess anxiolytic-like properties. Among the two, HBK-15 has stronger antidepressant-like properties, and HBK-14 displays greater anxiolytic-like activity. Lastly, we demonstrate the involvement of serotonergic system, particularly 5-HT1A receptor, in the antidepressant- and anxiolytic-like actions of investigated compounds