Apocynin: Chemical and biophysical properties of a NADPH oxidase inhibitor

Apocynin is the most employed inhibitor of NADPH oxidase (NOX), a multienzymatic complex capable of catalyzing the one-electron reduction of molecular oxygen to the superoxide anion. Despite controversies about its selectivity, apocynin has been used as one of the most promising drugs in experimental models of inflammatory and neurodegenerative diseases. Here, we aimed to study the chemical and biophysical properties of apocynin. The oxidation potential was determined by cyclic voltammetry (Epa = 0.76V), the hydrophobicity index was calculated (logP = 0.83) and the molar absorption coefficient was determined (��275nm = 1.1 �� 104 M-1 cm-1). Apocynin was a weak free radical scavenger (as measured using the DPPH, peroxyl radical and nitric oxide assays) when compared to protocatechuic acid, used here as a reference antioxidant. On the other hand, apocynin was more effective than protocatechuic acid as scavenger of the non-radical species hypochlorous acid. Apocynin reacted promptly with the non-radical reactive species H2O2 only in the presence of peroxidase. This finding is relevant, since it represents a new pathway for depleting H2O2 in cellular experimental models, besides the direct inhibition of NADPH oxidase. This could be relevant for its application as an inhibitor of NOX4, since this isoform produces H 2O2 and not superoxide anion. The binding parameters calculated by fluorescence quenching showed that apocynin binds to human serum albumin (HSA) with a binding affinity of 2.19 �� 104 M -1. The association did not alter the secondary and tertiary structure of HSA, as verified by synchronous fluorescence and circular dichroism. The displacement of fluorescent probes suggested that apocynin binds to site I and site II of HSA. Considering the current biomedical applications of this phytochemical, the dissemination of these chemical and biophysical properties can be very helpful for scientists and physicians interested in the use of apocynin.

Heat transfer and magnetovortical antiresonance of a ferrofluid with a rotating magnetic field

We investigate theoretically a ferrofluid in the presence of a rotating magnetic field using a phenomenological approach based on a equation of motion for the magnetization. We verify that the heating rates of the system display a heat transfer between the host liquid and the magnetic nanoparticles (MNPs), with symmetric profiles dependent on the vorticity value. As a result, the total heating rate reveals a magnetovortical antiresonance and characterizes the suppression of the dissipation. �� 2012 Springer Science+Business Media, LLC.

Low tungsten content of nanostructured material supported on carbon for the degradation of phenol

A comparative study using different mass proportions of WO3/C (1%, 5%, 10% and 15%) for H2O2 electrogeneration and subsequent phenol degradation was performed. To include the influence of the carbon substrate and the preparation methods, all synthesis parameters were evaluated. The WO3/C materials were prepared by a modified polymeric precursor method (PPM) and the sol-gel method (SGM) on Vulcan XC 72R and Printex L6 carbon supports, verifying the most efficient metal/carbon proportion. The materials were physically characterized by X-ray diffraction (XRD) and by X-ray photoelectron spectroscopy (XPS) techniques. The XRD and the XPS techniques identified just one phase containing WO3 and elevated oxygen concentration on carbon with the presence of WO3. The oxygen reduction reaction (ORR), studied by the rotating ring-disk electrode technique, showed that WO3/C material with the lowest tungsten content (1% WO3/C), supported on Vulcan XC 72R and prepared by SGM, was the most promising electrocatalyst for H2O2 electrogeneration. This material was then analyzed using a gas diffusion electrode (GDE) and 585mgL-1 of H2O2 was produced in acid media. This GDE was employed as a working electrode in an electrochemical cell to promote phenol degradation by an advanced oxidative process. The most efficient method applied was the photo-electro-Fenton; this method allowed for 65% degradation and 11% mineralization of phenol during a 2-h period. Following 12h of exhaustive electrolysis using the photo-electro-Fenton method, the total degradation of phenol was observed after 4h and the mineralization of phenol approached 75% after 12h. �� 2013 Elsevier B.V.

Efeito de agentes clareadores sobre a susceptibilidade do esmalte submetido a desafios erosivos in vitro

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Sensibilidade dolorosa e efetividade do clareamento dental de consult��rio

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Citotoxicidade e a����o antimicrobiana do cimento Portland associado a diferentes agentes radiopacificadores

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Avalia����o da citotoxicidade de cimentos endod��nticos quanto a libera����o de per��xido de hidrog��nio e ��xido n��trico em culturas de macr��fagos peritoneais de camundongos

P��s-gradua����o em Odontologia - FOAR

Efeitos imunol��gicos da ingest��o do produto de soja fermentado em ratos induzidos quimicamente com c��ncer de c��lon

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Atividade anti-tumoral e imunomodulat��ria de complexos de pal��dio (II) utilizando modelo experimental de Ehrlich

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Avalia����o da atividade imunol��gica In vitro de Alchornea ssp quanto �� produ����o de per��xido de hidrog��nio, ��xido n��trico e fator de necrose tumoral-alfa por macr��fagos murinos

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Efeito da pr��polis sobre par��metros imunol��gicos de camundongos Balb/c submetidos a estresse cr��nico

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Efeito protetor da pr��polis contra danos quimicamente induzidos no DNA

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Avalia����o de Reparo de DNA e Atividade Antioxidante do Extrato Etan��lico e Subst��ncias Isoladas de Casearia sylvestris

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Avalia����o da atividade biol��gica de uma nova naftoquinona extra��da de Paepalanthus latipes

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Influ��ncia da suplementa����o com citamina E(dl-alfa tocoferol) nas fun����es de mon��citos e polimorfonucleares de eq��inos da ra��a ��rabe submetidos ao exerc��cio f��sico

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)