Diego Alves

Antisecretory and antiulcer effects of diphenyl diselenide.

The antisecretory and antiulcer effects of diphenyl diselenide were studied in vivo and in vitro. Diphenyl diselenide, administered intraperitoneally prevented the development of gastric lesions induced by ethanol and indomethacin. There was no difference in plasma uric acid concentrations in diphenyl diselenide-treated rats with gastric lesions induced by 70% ethanol. There were no changes in TBARS levels in diphenyl diselenide-treated rats with gastric lesions induced by indomethacin and ethanol. Diphenyl diselenide (5, 10 and 50mg/kg) inhibited gastric acid secretion in pylorus-ligated rats. In vitro results demonstrated that diphenyl diselenide inhibited lipid peroxidation induced by Fe(2+)/ascorbate/H(2)O(2) and reduced K(+)-dependent ATPase activity. The mechanisms by which pre-administered diselenide protects the damaged area in the gastric mucosa are not clear but it appears that the antiulcer activity of diphenyl diselenide is the result of antisecretory activity, via inhibition of gastric K(+)-ATPase activity.

Glycerol as a recyclable solvent for copper-catalyzed cross-coupling reactions of diaryl diselenides with aryl boronic acids

We describe herein the use of glycerol as the solvent in the copper-catalyzed cross-coupling reaction of diaryl diselenides with arylboronic acids using CuI and DMSO as additive. This cross-coupling reaction was performed with diaryl diselenides and arylboronic acids bearing electron-withdrawing and electron-donating groups, affording the corresponding diaryl selenides in good to excellent yields. The glycerol–CuI mixture can be directly reused for further cross-coupling reactions.

Essential oil of the leaves of Eugenia uniflora L.: Antioxidant and antimicrobial properties

Essential oil (EO) of the leaves of Eugenia uniflora L. (Brazilian cherry tree) was evaluated for its antioxidant, antibacterial and antifungal properties. The acute toxicity of the EO administered by oral route was also evaluated in mice. The EO exhibited antioxidant activity in the DPPH, ABTS and FRAP assays and reduced lipid peroxidation in the kidney of mice. The EO also showed antimicrobial activity against two important pathogenic bacteria, Staphylococcus aureus and Listeria monocytogenes, and against two fungi of the Candida species, C. lipolytica and C. guilliermondii. Acute administration of the EO by the oral route did not cause lethality or toxicological effects in mice. These findings suggest that the EO of the leaves of E. uniflora may have the potential for use in the pharmaceutical industry.

Copper iodide-catalyzed cyclization of (Z)-chalcogenoenynes.

We present here our results of the efficient copper-catalyzed cyclizations of chalcogenoenynes and establish a route to obtain 3-substituted chalcogenophenes in good to excellent yields. In addition, the obtained chalcogenophenes were readily transformed to more complex products using the palladium-catalyzed cross-coupling reactions with boronic acids to give Suzuki-type products in good yields.

Recoverable Cu/SiO2 composite-catalysed click synthesis of 1,2,3-triazoles in water media

An eco-friendly multicomponent reaction for the synthesis of 1,2,3-triazoles using a recoverable and recyclable Cu/SiO2 composite as the catalyst is reported. The reaction proceeds by mixing the benzyl halide, sodium azide, the alkyne and the catalyst in an aqueous medium to afford the desired products in excellent yields. The heterogeneous catalytic system showed high efficiency, performing the multicomponent Huisgen reaction in a green approach based on recoverability, recyclability and avoidance of waste. Microwave irradiation was also applied, substituting for conventional heating, resulting in excellent yields of the products with a dramatic reduction in the reaction time.

In vitro antioxidant activity and in vivo antidepressant-like effect of α-(phenylselanyl) acetophenone in mice.

In this study, the antioxidant and antidepressant-like effects of α-(phenylselanyl) acetophenone (PSAP), an organoselenium compound, were investigated. To assess the in vitro antioxidant properties, PSAP was evaluated in four test systems (DPPH, ABTS, FRAP and inhibition of lipid peroxidation). PSAP (100-500 μM) showed potent antioxidant activity and protected against lipid peroxidation. Additionally, we investigated whether PSAP, when administered in mice (100, 200 and 400mg/kg, per oral, p.o.), could cause acute toxicity. Our results demonstrated that PSAP did not cause the death of any animal, significantly reduce body weight or cause any oxidative tissue stress following treatment. This study also evaluated the effect of PSAP (0.1-10 mg/kg, p.o) on mice in a forced swim test (FST) and tail suspension test (TST), assays that are predictive of depressant activity and motor activity in the open-field. PSAP (5-10 mg/kg) significantly reduced immobility time in the FST and TST without affecting motor activity. In addition, the antidepressant-like effect caused by PSAP (5m/kg, p.o) in mice during the TST was dependent on an interaction with the serotonergic system (5-HT(1A) receptors), but not with the noradrenergic, dopaminergic or adenosinergic system. Together, these results suggest that PSAP possesses antioxidant and antidepressant-like properties and may be of interest as a therapeutic agent for the treatment of depressive disorders.

Synthesis of diaryl selenides using electrophilic selenium species and nucleophilic boron reagents in ionic liquids

We described herein the use of imidazolium ionic liquids [bmim]PF6 and [bmim]BF4 in the selective, metal and catalyst-free synthesis of unsymmetrical diaryl selenides by electrophilic substitution in arylboron reagents with arylselenium halides (Cl and Br) at room temperature. This is a general substitution reaction and it was performed with arylboronic acids or potassium aryltrifluoroborates bearing electron-withdrawing or electron-donating groups, affording the corresponding diaryl selenides in good to excellent yields. The ionic liquid [bmim][PF6] was easily recovered and utilized for further substitution reactions.

Sonochemistry: An efficient alternative to the synthesis of 3-selanylindoles using CuI as catalyst

Ultrasonic (US) irradiation was successfully used as an alternative energy source to prepare 3-selanylindoles through the direct selanylation of indoles with diorganyl diselenides using CuI (20 mol%) as catalyst and DMSO as the solvent. By using this US-promoted reaction, eleven 3-organylselanylindoles were prepared selectively and in good yields. A comparative study between the reactions under conventional heating, microwave and ultrasound irradiations was performed, and it was observed advantage in using US over the other heating systems.

Room-Temperature Organocatalytic Cycloaddition of Azides with β-Keto Sulfones: Toward Sulfonyl-1,2,3-triazoles.

Organocatalytic enamine-azide [3 + 2] cycloadditions between β-keto sulfones and aryl azides can be performed at room temperature in good to excellent yields of products in the presence of catalytic amounts of pyrrolidine (5 mol %). The proposed organocatalytic methodology was found to be applicable to β-keto arylsulfones containing a range of substituents. A wide variety of aryl azides also work. Basically, this constitutes a remarkably efficient protocol for the synthesis of novel 1,2,3-triazole compounds.

Involvement of the dopaminergic and serotonergic systems in the antidepressant-like effect caused by 4-phenyl-1-(phenylselanylmethyl)-1,2,3-triazole.

AIMS The study investigated the antidepressant-like effect and acute toxicity of 4-phenyl-1-(phenylselanylmethyl)-1,2,3-triazole (Se-TZ), an organoselenium-containing heterocycle compound in mice. MAIN METHODS The antidepressant-like effect of Se-TZ (1-50mg/kg) and its mechanism of action, was analyzed in the tail suspension test (TST) in male C57BL/6J mice. Additionally, the levels of the monoamines and their metabolites in cerebral cortex and hippocampus were analyzed by high-performance liquid chromatography. To investigate the potential acute toxicity caused by Se-TZ, the mice received a single oral dose of Se-TZ (1-50mg/kg), and after 72h were performed the assays. KEY FINDINGS The Se-TZ (5-50mg/kg) significantly reduced immobility time in TST without altering locomotor and exploratory activities. The antidepressant-like effect of Se-TZ (25mg/kg) in the TST was prevented by pre-treatment of mice with SCH23390, sulpiride and methysergide, but not with prazosin, yohimbine and propranolol. Se-TZ, increased monoamine neurotransmitters dopamine and serotonin levels in the cerebral cortex and hippocampus, whereas norepinephrine turnover was not changed. This study also demonstrated that the Se-TZ, did not cause the acute toxicity in biochemical markers hepatic and renal investigated. The results evidenced that exposure to Se-TZ caused a significant increase in the catalase (CAT) activity in the cerebral cortex and hippocampus, however the glutathione S-transferase (GST) activity increased only in the cerebral cortex. SIGNIFICANCE These results suggest that Se-TZ demonstrated antidepressant-like effect, mediated via the central dopaminergic and serotoninergic neurotransmitter systems which may be of interest as a therapeutic agent for the treatment of depressive disorders.