Resumo em Inglês:

Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognite impairment and personality changes. The development of drugs for the treatment of the cognitive deficits of AD has focused on agents which counteract loss in cholinergic activities. These symptons of AD have been successfully treated with acetylcholinesterase (AchE) inhibitors (eg. galanthamine). There still is great interest in finding better AchE inhibitors. We use Ellmann's microplate assay and silica gel thin-layer chromatography (TLC) to screen natural products from plants as new sources of AchE inhibitors.

Resumo em Inglês:

Zeolite catalysts have been extensively used in petroleum refining and the chemical industry although they are deactivated by coke deposition. In order to find the best condition to avoid deactivation, the coke formation on H-mordenite was studied in this work. The coke was produced during benzene transalkylation with C9+ aromatics, under several reaction conditions. It was found that hydrogenated coke was produced in all samples without affecting the selectivity of toluene and xylene formation. This is explained in terms of the mordenite structure and the presence of hydrogen.

Resumo em Inglês:

The phytochemical investigation of the chloroformic and methanolic extracts of the Baccharis pseudotenuifolia led to the isolation of triterpenes, steroids and flavonoids. From chloroformic extract were isolated oleanolic acid and alpha-spinasterol while from methanolic extract were isolated the flavonoids: hispidulin, naringenin, 3'-methoxy-luteolin, apigenin, kaempferol, eriodyctiol, aromadendrin, quercetin, 3'-methoxy-quercetin, quercetin-3-O-rhamnoside and quercetin-3-O-glucoside. The structure of these compounds were identified by IR, CG/MS, ¹H and 13C NMR spectral analysis and comparison with literature. In addition, the extracts were evaluated by means of Brine Shrimp Lethality test and the highier activity was observed in the chloroformic extract.

Resumo em Inglês:

A model based on chemical structure was developed for the accurate prediction of octanol/water partition coefficient (K OW) of polychlorinated biphenyls (PCBs), which are molecules of environmental interest. Partial least squares (PLS) was used to build the regression model. Topological indices were used as molecular descriptors. Variable selection was performed by Hierarchical Cluster Analysis (HCA). In the modeling process, the experimental K OW measured for 30 PCBs by thin-layer chromatography - retention time (TLC-RT) has been used. The developed model (Q² = 0,990 and r² = 0,994) was used to estimate the log K OW values for the 179 PCB congeners whose K OW data have not yet been measured by TLC-RT method. The results showed that topological indices can be very useful to predict the K OW.

Resumo em Inglês:

Phytochemical investigation of hexanic extract of leaves of Rollinia laurifolia afforded three known acetogenins, uvariamicin-I (1), solamin(2) and gonionenin(3), for the first time isolated from Rollinia genus. The structures of 1, 2 and 3 were elucidated by spectroscopic methods.

Resumo em Inglês:

Sequential extraction is not totally effective to dissolve distinct forms of trace elements. The extractive solution, for example, can dissolve less of the target fraction and more than another not wished fraction. The goal of this work is to compare the extraction of native iron with three sequential extraction methods of the heavy metals, using three soils with different physical chemistry characteristics: a histosol, an oxisol, and a mollisol. The results obtained in this work demonstrate that a smaller relation soil/extractor results in a larger extraction in almost all phases. The use of many stages of the sequential extraction, with the purpose of more association of the metal with different components of the soil, can result, among other things, in modification of the substratum by the action of the reagents used, besides reducing the selectivity of the more specific extractors. Readsorption and redistribution of the heavy metals could have happened with larger intensity in the fraction where hidroxilamine was used with higher temperature. Sequential extraction of iron, without enrichment of soil samples, in the respective fractions in each method, it was important to better understand the behavior of the reagents considered specific to each form of the metal in soil.

Resumo em Inglês:

The present paper describes the chemical composition and biological activities of artichoke cultivated in Brazil. Our studies demonstrated that glycosyl flavonoids (cynaroside and scolymoside), are the major constituents, along with cynaropicrin, a sesquiterpene lactone, and the triterpene lupeol. Cynarin, which is the main compound described for artichoke, was detected in very low concentration. Hexanic fraction exhibited considerable cytotoxicity and diuretic activities.

Resumo em Inglês:

Phytochemical investigation of the aerial parts and roots of Mucuna cinerea led to the isolation of a mixture of fatty acids, triacylglicerols, beta-sitosterol, stigmasterol, stigmasterol glucoside, daucosterol, asperglaucide (4) and the isoflavonoids prunetin (1), genistein (2), medicarpin (3), daidzein (5), 7-O-alpha-glycopiranosyl daidzein (6). An in vitro bioassay was carried out with compounds 1-4, at the concentration of 50 and 5 mug mL-1 against the phytonematodes M. incognita and H. glycines. Although the four compounds showed some nematocidal property, the most active was (1), causing 70% mortality of M. incognita at the concentration of 50 mug mL-1.

Resumo em Inglês:

Cisplatin is very effective in the treatment of metastatic breast cancer. However, the development of cellular resistance is a serious problem in cisplatin chemotherapy. In the present work, the effects of dipyridamole (DPM) on the cellular accumulation and cytotoxicity of cisplatin was studied in cisplatinsensitive (MDA/S) and cisplatinresistant (MDA/R) human breast cancer cells. In the presence of 30 µM DPM, the IC50 of cisplatin was reduced by 39% for both cell lines. Combination index analysis revealed that cisplatin and dipyridamole interact synergistically in MDA/R cells. In the MDA/S cells, the cellular accumulation of cisplatin increased by 57 ± 8% in the presence of 30 µM DPM. In the MDA/R cells, the cellular accumulation of cisplatin remained the same with or without 30 µM DPM. The results suggest that the enhancement of cisplatin cytotoxicity by DPM in MDA/S cells may be related to a DPM-induced increase in cisplatin accumulation, but the enhanced cytotoxicity in MDA/R cells employs a mechanism that does not involve an increase in the cellular accumulation of cisplatin.

Resumo em Inglês:

The determination of fractal dimension (D) of humic particles was achieved by the turbidimetric technique where diluted suspensions of humic acids, in different experimental conditions, were analyzed by spectrophotometry UV-Vis. The slope of the lines (beta) was taken from the graphics (logtauvs loglambda) to obtain D. The results show that the values of D changed according to pH (3.0, 5.0 and 7.0), temperature (25 and 5 ºC) and shaking (magnetic and horizontal). In general, the value of D decreased with the increment of pH, increase of shaking and decrease of temperature.

Resumo em Inglês:

Depression is a widespread humor disturbance promoted mainly by depletion of biogenic neurotransmitter amines involved in the CNS synapses. Effective drug treatments for depression have been available for more than forty years. Despite its remarkable structural diversity, this paper discuss under the medicinal chemistry point of view, all different classes of "monoamine based" antidepressant drugs, emphasizing the rational design, structure-activity relationships (SAR), biotransformation and physico-chemical properties related with antidepressant activity and molecular mechanism of action.

Resumo em Inglês:

During the last two decades there has been increasing concern within the scientific community related to the effects of indoor air quality on health. Changes in building design devised to improve energy efficiency and new synthetic building materials have contributed to increase pollutant concentrations. These factors have generated poor air quality and caused the development of a lot of symptoms known as Sick Building Syndrome (SBS). In Brazil, there are few studies in this area, collected in this review to support researches and awareness of the need to adopt preventive measures to reach a better quality for the Indoor Environment.

Resumo em Inglês:

Currently available anti-HIV drugs can be classified into three categories: nucleoside analogue reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs). In addition to the reverse transcriptase (RT) and protease reaction, various other events in the HIV replicative cycle can be considered as potential targets for chemotherapeutic intervention: (1) viral adsorption, through binding to the viral envelope glycoprotein gp120; (2) viral entry, through blockage of the viral coreceptors CXCR4 and CCR5; (3) virus-cell fusion, through binding to the viral envelope glycoprotein gp 41; (4) viral assembly and disassembly through NCp7 zinc finger-targeted agents; (5) proviral DNA integration, through integrase inhibitors and (6) viral mRNA transcription, through inhibitors of the transcription (transactivation) process. Also, various new NRTIs, NNRTIs and PIs have been developed, possessing different improved characteristics.

Resumo em Inglês:

A brief discussion about the hydrogen peroxide importance and its determination is presented. It was emphasized some consideration of the H2O2 as reagent (separated or combined), uses and methods of analysis (techniques, detection limits, linear response intervals, sensor specifications). Moreover, it was presented several applications, such as in environmental, pharmaceutical, medicine and food samples.

Resumo em Inglês:

Self-assembled monolayers (SAMs) modified electrodes exhibit unique behavior that can greatly benefit electrochemical sensing. This brief review highlights the applications of SAM modified electrodes in electroanalytical chemistry. After a general introduction, which includes the approaches for SAM development, different electrochemical systems for detecting inorganic and organic species are described and discussed. Special attention to the coupling of biological sensing element to the SAM is given, which can selectively recognize the analyte. Future prospects are also evaluated.

Resumo em Inglês:

Many substances from different sources have been used by men for decades to control insects. After the 2nd World War, the use of inorganic compounds have declined drastically and natural products, as well as synthetic derivatives, have been widely used instead. The search for natural alternatives have improved the development of bench top bioassays and an array of synthetic approaches for known and novel natural products that shows relevant activities as feeding supressors and deterrents. The studies concerning mode of action and environmental impact of these substances, that may be biodegradable and selective for undesired insects, had led to the evaluation and discovery of a number of molecules, mostly terpenoids and alkaloids, that are well reported as candidates for inseticidal compounds that could be an effective alternative for insects control with a lower impact on human health, household animals and the environment.

Resumo em Inglês:

Beowulf cluster is perhaps the cheapest way to construct a high performance computers. The strategy of reaching a high power computing isn't so difficult, but buying and configurating should be done carefully. Technical aspects of hardware components and message-passing libraries are considered, with some results given as examples.

Resumo em Inglês:

Naphthoquinones have been extensively studied due to their activity as topoisomerase inhibitors. These enzymes are critical to DNA replication in cells. In addition, naphthoquinones have been shown to induce what are known as "reactive oxygen species" that can cause damage to cells. beta-Lapachone is a very important pyranaphthoquinone obtained from the heartwood of the lapacho tree, Tabebuia avellanedae Lorentz ex. Griseb. (Bignoniaceae), and other Tabebuia trees native to Central and South America and chemically from lapachol. beta-Lapachone has a diversity of useful biological activities against various cancer cell lines such as human ovarian and prostate tumors and, at lower doses is a radiosensitizer of several human cancer cell lines. It gives rise to a variety of effects in vitro including the inhibition or activation of topoisomerase I an II in a distinct manner from that of other topoisomerase inhibitors. This review intend to discuss some details of the mechanisms of quinone-induced cell damage and death, and we also summarize results of the literature indicating that b-Lapachone may take part in quinone-elicited apoptosis despite the fact that its mechanism of action in vivo and its targets are still unknown.

Resumo em Inglês:

When laboratory intercomparison exercises are conducted, there is no a priori dependence of the concentration of a certain compound determined in one laboratory to that determined by another(s). The same applies when comparing different methodologies. A existing data set of total mercury readings in fish muscle samples involved in a Brazilian intercomparison exercise was used to show that correlation analysis is the most effective statistical tool in this kind of experiments. Problems associated with alternative analytical tools such as mean or paired 't'-test comparison and regression analysis are discussed.

Resumo em Inglês:

The optimization of ferrate(VI) ion generation has been studied due to its favorable characteristics for application in several fields, including environmental quality control. The paper presents the best conditions for electrolytic generation of ferrate(VI) in alkaline media. An appropriate electrolyte was NaOH, 10 mol/L. Circulation of the electrolyte solution was important to avoid acidification close to the anode surface. An anode pre-cleaning with 10% HCl was more efficient than a cathodic pre-polarization. Among the distinct anode materials tested, pig iron showed the best performance, allowing up to 20 g/L of Na2FeO4, in 10 mol/L NaOH solution to be obtained, after 7 h of reactor operation, which is a concentration higher than those found in literature for alternative processes.

Resumo em Inglês:

An experiment for the synthesis of isobutylene from tert-butanol dehydratation using oxalic acid as catalyst, followed by preparations of tert-butyl benzoate and tert-butyl cinnamate is described. The synthesis are simple, requiring two periods of 4 hours and are suitable for undergraduate organic chemistry experimental courses.

Resumo em Inglês:

Molecular Modeling is an important tool in drug design and it is very useful to predict biological activity from a library of compounds. A wide variety of computer programs and methods have been developed to visualize the tridimensional geometry and calculate physical properties of drugs. In this work, we describe a practical approach of molecular modeling as a powerful tool to study structure-activity relationships of drugs, including some antibacterials, hormones, cholinergic and adrenergic agents. At first, the students learn how to draw 3D structures and use them to perform conformational and molecular analysis. Thus, they compare drugs with similar pharmacological activity by superimposing one structure on the top of another and evaluate the geometry and physical properties.

Resumo em Inglês:

This article describes the history of four decades of activities in the Institute of Chemistry of Araraquara, UNESP: the beginning, the evolution of undergraduate and graduate courses and the infra-structure of teaching and research.

Resumo em Inglês:

Over the last five years there have been significant changes in higher education in Brazil as well as in research funding. As a contribution to the development of Science and Technology, and aiming to portray Chemistry today in Brazil, in the context of last year´s elections for President, State Governors, National Congress and Legislative Chamber, the Directors and Consulting Council of the Brazilian Chemical Society, SBQ, initiated in 2002 a series of activities to produce a document entitled Mobilizing Axes in Chemistry. This discusses undergraduate and graduate teaching in Chemistry, a new model for research funding, and the overall state of the art, and future perspectives. Six mobilizing axes have been identified and discussed to date: 1. Training of highly qualified personnel; 2. Decentralization, and discouragement of institutional in-breeding; 3. Stimulation of entrepreneurship and interdisciplinarity; 4. A guaranteed budget for Science and Technology; 5. Proactive interaction of academics with economic activity; and 6. Removal of institutional bottle-necks of all sorts. The Brazilian Chemical Society hopes that the new administration will in the near future begin the task of improving the national education system and increase funding for Science and Technology.