1,5-Diphenyl-4,8-bis(3-phenylpyrazol-1-yl)pyrazabole

The six-membered B(2)H(4) ring of the title compound, C(36)H(30)B(2)N(8), adopts a slightly distorted boat conformation, with the terminal B substituents in a trans orientation. One 3-phenylpyrazolyl group is in an equatorial position, whereas the second is in an axial position with respect to the plane defined by the B atoms.

A novel hybrid composite formed by reaction of 4,5-diphenyl-2-imidazolethiol with hexacyanoferrate (iii) and subsequent reaction with copper (ii): preparation, characterization and a voltammetric application for determination of l-glutatione

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hypolipemic and antioxidant activities from Tamarindus indica L. pulp fruit extract in hypercholesterolemic hamsters

Dietary modifications may significantly reduce cardiovascular disease (CVD) risk factors, including cholesterol and atherosclerosis. The present study addressed the effects of the crude extract from the pulp fruit of Tamarindus indica L. on lipid serum levels and early atherosclerotic lesions in hypercholesterolemic hamsters in vivo, and the extract's antioxidant action, in vitro. Animals were fed on either chow or atherogenic diet during 10 weeks and concomitantly received either water or T indica L. extract for drinking. Treatment of hypercholesterolemic hamsters with the T. indica pulp fruit extract (5%) led to a decrease in the levels of serum total cholesterol (50%), non-HDL cholesterol (73%) and triglyceride (60%), and to an increase of high-density lipoprotein (HDL) cholesterol levels (61%). In vitro, the extract presented radical scavenging ability, as assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals assays, and led to decreased lipid peroxidation in serum, as assessed by the thiobarbituric acid reactive substances (TBARS) assay. In vivo, the extract improved the efficiency of the antioxidant defense system, as assessed by the superoxide dismutase, catalase and glutathione peroxidase activities. Together these results indicate the potential of tamarind extracts in diminishing the risk of atherosclerosis development in humans. (c) 2005 Elsevier Ltd. All rights reserved.

Radical scavenging activity of orange and tangerine varieties cultivated in Brazil

Four citrus fruit varieties cultivated in Brazil (two kinds of sweet orange and two kinds of tangerine) were analyzed for physicochemical characteristics contents of total phenolics, total carotenoids and ascorbic acid, and antioxidant activities. The antioxidant activities of aqueous, methanolic, and acetone extracts of the citrus fruit juices were assessed on the basis of their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH(center dot)). The cravo tangerine has the highest content of citric acid, while the pera orange is richest in ascorbic acid. The lima orange has the highest total phenolic contents, and the ponkan the highest total carotenoids. The antioxidant activities, expressed as the concentration of antioxidant able to scavenge 50% of the initial DPPH(center dot) (EC(50)), ranged from 139.1+/-27.3 to 182.2+/-28.8 g extract/l for juice of orange varieties and 186.3+/-29.6 to 275.5+/-3.3g extract/l for juice of tangerine citrus varieties. In methanolic extracts the EC(50) ranged from 192.5+/-43.1 to 267.4+/-41.4 g extract/l for orange varieties and from 225.2+/-69.8 to 336.3+/-27.2 g extract/l for tangerine varieties. For EC(50) values of acetone fractions, there were no statistically significant differences between the different varieties. For every citrus fruit in the present study, the radical scavenging capacity was higher in the aqueous than in the methanolic or acetone fractions.

Chemical Composition and Antioxidant and Antimycobacterial Activities of Bromelia balansae (Bromeliaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cytotoxic lignans from the stems of Styrax camporum (Styracaceae)

An ethanolic extract from the stems of Styrax camporum Pohl (Styracaceae), a plant traditionally used for gastrointestinal diseases, was fractionated and subjected to flash chromatography and afforded two benzofuran lignans, egonol and homoegonol, and one furofuran lignan, (+/-) syringaresinol, which were identified by spectral data interpretation. Their cytotoxic activities against Hep-2 (larynx epidermoid carcinoma), HeLa (human cervix carcinoma) and C6 (rat glioma) cell lines were evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay at several concentrations for 24 h. Activities could be observed for egonol against C6 (IC50 = 3.2 mu g/mL) and Hep-2 (IC50 = 3.6 mu g/mL) cell lines, and for homoegonol against C6 (IC50 = 4.9 mu g/mL) and HeLa (IC50 =- 5.3 mu g/mL) cells.

Antioxidant activity of isocoumarins isolated from Paepalanthus bromelioides on mitochondria

The isocoumarins (1-50 mu M) paepalantine (9,10-dihydroxy-5,7-dimethoxy-1H-naptho(2,3c)pyran-1-one), 8,8 '-paepalantine dimer, and vioxanthin isolated from Paepalanthus bromelioides, were assessed for antioxidant activity using isolated rat liver mitochondria and non-mitochondrial systems, and compared with the flavonoid quercetin. The paepalantine and paepalantine dimers, but not vioxanthin, were effective at scavenging both 1,1-diphenyl-2-picrylhydrazyl (DPPH*) and superoxide (O-2(-)) radicals in non-mitochondrial systems, and protected mitochondria from tert-butylhydroperoxide-induced H2O2 accumulation and Fe2+ -citrate-mediated mitochondrial membrane lipid peroxidation, with almost the same potency as quercetin. These results point towards paepalantine, followed by paepalantine dimer, as being a powerful agent affording protection, apparently via O-2(-) scavenging, from oxidative stress conditions imposed on mitochondria, the main intracellular source and target of those reactive oxygen species. This strong antioxidant action of paepalantine was reproduced in HepG2 cells exposed to oxidative stress condition induced by H2O2. (C) 2007 Elsevier Ltd. All rights reserved.

Effects of isocoumarins isolated from Paepalanthus bromelioides on mitochondria: Uncoupling, and induction/inhibition of mitochondrial permeability transition

Isolated mitochondria may undergo uncoupling, and in presence of Ca2+ at different conditions, a mitochondrial permeability transition (MPT) linked to protein,thiol oxidation, and demonstrated by CsA-sensitive mitochondrial swelling; these processes may cause cell death either by necrosis or by apoptosis. Isocoumarins isolated from the Brazilian plant Paepalanthus bromelioides (Eriocaulaceae) paepalantine (9,10-dihydroxy-5,7-dimethoxy-1H-naptho(2,3c)pyran-1-one), 8,8'-paepalantine dimer, and vioxanthin were assayed at 1-50 mu M on isolated rat liver mitochondria, for respiration, MPT, protein thiol oxidation, and interaction with the mitochondrial membrane using 1,6-diphenyl-1,3,5-hexatriene (DPH). The isocoumarins did not significantly affect state 3 respiration of succinate-energized mitochondria; they did however, stimulate 4 respiration, indicating mitochondrial uncoupling. Induction of MPT and protein thiol oxidation were assessed in succinate-energized mitochondria exposed to 10 mu M Ca2+; inhibition of these processes was assessed in non-energized organelles in the presence of 300 mu M t-butyl hydroperoxide plus 500 mu M Ca2+. Only paepalantine was an effective MPT/protein thiol oxidation inducer, also releasing cytochrome c from mitochondria; the protein thiol oxidation, unlike mitochondrial swelling, was neither inhibited by CsA nor dependent on the presence of Ca2+. Vioxanthin was an effective inhibitor of MPT/protein thiol oxidation. All isocoumarins inserted deeply into the mitochondrial membrane, but only paepalantine dimer and vioxantin decreased the membrane's fluidity. A direct reaction with mitochondrial membrane protein thiols, involving an oxidation of these groups, is proposed to account for MPT induction by paepalantine, while a restriction of oxidation of these same thiol groups imposed by the decrease of membrane fluidity, is proposed to account for MPT inhibition by vioxanthin. (c) 2006 Published by Elsevier B.V..

Cytotoxicity of chlorhexidine digluconate to murine macrophages and its effect on hydrogen peroxide and nitric oxide induction

Chlorhexidine, even at low concentrations, is toxic for a variety of eukaryotic cells; however, its effects on host immune cells are not well known. We evaluated in vitro chlorhexidine-induced cytotoxicity and its effects on reactive oxygen/nitrogen intermediate induction by murine peritoneal macrophages. Thioglycollate-induced cells were obtained from Swiss mice by peritoneal lavage with 5 ml of 10 mM phosphate-buffered saline, washed twice and resuspended (10(6) cells/ml) in appropriate medium for each test. Cell preparations contained more than 95% macrophages. The cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and the presence of hydrogen peroxide (H2O2) and nitric oxide (NO) by the horseradish peroxidase-dependent oxidation of phenol red and Griess reaction, respectively. The midpoint cytotoxicity values for 1- and 24-h exposures were 61.12 ± 2.46 and 21.22 ± 2.44 µg/ml, respectively. Chlorhexidine did not induce synthesis or liberation of reactive oxygen/nitrogen intermediates. When macrophages were treated with various sub-toxic doses for 1 h (1, 5, 10, and 20 µg/ml) and 24 h (0.5, 1, and 5 µg/ml) and stimulated with 200 nM phorbol myristate acetate (PMA) solution, the H2O2 production was not altered; however, the NO production induced by 10 µg/ml lipopolysaccharide (LPS) solution varied from 14.47 ± 1.46 to 22.35 ± 1.94 µmol/l and 13.50 ± 1.42 to 20.44 ± 1.40 µmol/l (N = 5). The results showed that chlorhexidine has no immunostimulating activity and sub-toxic concentrations did not affect the response of macrophages to the soluble stimulus PMA but can interfere with the receptor-dependent stimulus LPS.

Antimicrobial, Cytotoxic and Antioxidant Activities and Determination of the Total Tannin Content of Bark Extracts Endopleura uchi

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A tellurium-based cathepsin B inhibitor: Molecular structure, modelling, molecular docking and biological evaluation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Magnetic field effects on the conductivity of organic bipolar and unipolar devices at room temperature

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Interconverting flavanone glucosides and other phenolic compounds in Lippia salviaefolia Cham. ethanol extracts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemical constituents and antioxidant activity from leaves extracts of terminalia fogiafolia mart. et zucc

CHEMICAL CONSTITUENTS and ANTIOXIDANT ACTIVITY FROM LEAVES EXTRACTS of Terminalia fagifolia Mart. et Zucc. Phytochemical investigation of ethanolic leaves extracts of T. fagifolia led to the isolation of (+)-catechin, sitosterol-3-O-beta-D-glucopyranoside, alpha- and beta-tocopherol, a mixture of lupeol, alpha- and beta-amyrin, sitosterol and a mixture of glicosid flavonoids (CP-13). The structures of these compounds were identified by (1)H and (13)C NMR spectral analysis and comparison with literature data. Absolute configuration of the catechin was determinate by circular dichroism. Antioxidant activity (EC(50)), evaluated by 2,2-diphenyl-1-picrylhidrazyl (DPPH) assay system, decreased in the order: (+)-catechin > hydroalcoholic fraction > CP-13 > aqueous fraction > EtOH extract.

Cure Kinetic of Castor Oil-Based Polyurethane

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)