939 resultados para ARYL RADICALS


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Pós-graduação em Química - IQ

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

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Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Multicomponent reactions between phenols, β-diesters and benzaldehydes for the synthesis of 4-aryl-3,4-dihydrocoumarin derivatives were carried out under mild conditions (room temperature) and presented moderate yields (38-88%) and reasonable reaction times (2-4 days), using niobium pentachloride as a catalyst.

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Matayba guianensis Aubl . is a shrubby or arborial Sapindaceae quite common in the Brazilian Cerrado with a key role in providing resources for ants and bees. It presents a rapid growth, and is important for the recovery of degraded areas, but little is known about its seedlings production. Therefore, the aim of this study was to describe the morphology of the branch and the seed germination and of seedling Matayba guianensis Aubl . in its post-seminal development and define the type of substrate and container suitable for seedling emergence and seedling production of this species. We evaluated three types of containers: black polyethylene bags, cartridge and polystyrene tray, with 5 kinds of substrates: sand, earth, earth - sand - manure (1:1:1); commercial substrate, and coconut fiber, with 4 replicates of 25 seeds per treatment . The branch, fruit, seed, seedling and their morphological events were described. The branch is cylindrical with paripinnate and alternate leaves, the fruit is dry and dehiscent. The seeds have a large amount of aryl, and the germination is cryptocotylar and hypogeal. The highest percentage of emergence occurred in styrofoam container with 91 % of the seeds germinated in commercial substrate , followed by coconut fiber (88 %). The development of root and stem were higher in tubes and plastic bags , using coconut fiber or commercial substrate.

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Cocaine is a widely used drug and its abuse is associated with physical, psychiatric and social problems. Abnormalities in newborns have been demonstrated to be due to the toxic effects of cocaine during fetal development. The mechanism by which cocaine causes neurological damage is complex and involves interactions of the drug with several neurotransmitter systems, such as the increase of extracellular levels of dopamine and free radicals, and modulation of transcription factors. The aim of this review was to evaluate the importance of the dopaminergic system and the participation of inflammatory signaling in cocaine neurotoxicity. Our study showed that cocaine activates the transcription factors NF-κB and CREB, which regulate genes involved in cellular death. GBR 12909 (an inhibitor of dopamine reuptake), lidocaine (a local anesthetic), and dopamine did not activate NF-κB in the same way as cocaine. However, the attenuation of NF-κB activity after the pretreatment of the cells with SCH 23390, a D1 receptor antagonist, suggests that the activation of NF-κB by cocaine is, at least partially, due to activation of D1 receptors. NF-κB seems to have a protective role in these cells because its inhibition increased cellular death caused by cocaine. The increase in BDNF (brain-derived neurotrophic factor) mRNA can also be related to the protective role of both CREB and NF-κB transcription factors. An understanding of the mechanisms by which cocaine induces cell death in the brain will contribute to the development of new therapies for drug abusers, which can help to slow down the progress of degenerative processes.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Although the exact cause of neuronal loss in Parkinson's disease is not known, evidence points to oxidative stress and the production of reactive oxygen species as the main events that occur in the substantia nigra pars compacta of the brain of parkinsonians. EGb761 is an extract of the leaves from the Ginkgo biloba tree that has been reported as an antioxidant and neuroprotective agent. The objective of this work was to perform a systematic review of the studies that analysed the effect of Ginkgo biloba extract on Parkinson's disease or Parkinsonism. This research was conducted using the following databases: Medline, PsycInfo, Cinahl, Sigle, Lilacs, Scielo, Cochrane Library, and Embase. Initially, we selected 32 articles. After a more detailed analysis, only 10 articles remained. One of the hypotheses for the positive effect of EGb761 on Parkinson's disease is the reduction or inhibition of monoamine-oxidase activity. This enzyme metabolises dopamine, inducing the formation of free radicals, which in turn damage nigrostriatal neurons. Another hypothesis is that the neuroprotective effect of EGb761 against 6-hydroxydopamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and MPP+ toxins. As there are few studies on the effect of EGb761 on humans, this review could contribute new data to further the discussion of this issue.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)