Biologia química: uma estratégia moderna para a pesquisa em produtos naturais

This paper presents an overview of the Natural Products Research in Brazil in the last five years (2002-2006), and also discusses how some relevant aspects of the Chemical Biology area could create new research opportunities and challenges for the natural product chemists. In addition, some aspects of the scientific policies and their impact on current projects are discussed.

Determinação voltamétrica do herbicida glifosato em águas naturais utilizando eletrodo de cobre

The aim of this work was to investigate the copper electrode behavior in the voltammetric determination of glyphosate. The best conditions for this determination are phosphate buffer 0.05 mol L-1 and pH 7.3, and the peak potential is observed at 187 mV. LD and LQ values are 59 µg L-1 e 196 µg L-1, respectively. A water sample was analysed for glyphosate and identical results were obtained by using the analytical curve and the standard addition method. The comparison with a voltammetric method with Hg electrode, after a reaction with nitrite, showed quite concordant results for the analysis of the surface water sample. Therefore, the proposed method can be applied to direct determinations of the herbicide in waters, decreasing the time of analysis; besides, the method is in agreement with the "green chemistry" concept.

Metátese de olefinas aplicada ao fechamento de anéis: uma ferramenta poderosa para a síntese de macrociclos naturais

For a quarter of a century, metathesis has become indispensable for the synthesis of natural and non-natural products, particularly of biologically active compounds. This review illustrates through a maximum of appropriate examples the power and the versatility of the metathesis ring-closure (RCM) reaction as a key ring-closure methodology for the synthesis of natural macrocycles. Its high functional group compatibility as well as the possibility of further transformations makes this reaction a powerful tool in the cases where the structural framework and function requirements are difficult to meet.

Procedimentos analíticos para identificação de antocianinas presentes em extratos naturais

Anthocyanins are among the most important plant pigments. Due to their potential benefits for human health, there is considerable interest in these natural pigments. Nonetheless, there is great difficulty in finding a technique that could provide the identification of structurally similar compounds and estimate the number and concentration of the species present. A lot of techniques have been tried to find the best methodology to extract information from these systems. In this paper, a review of the most important procedures is given, from the extraction to the identification of anthocyanins in natural extracts.

Um novo procedimento de síntese da zeólita A empregando argilas naturais

This work proposes the synthesis of zeolite A by IZA standard proceedures starting from a natural clay. The clay was used in its natural form and after calcination at 900ºC. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and porosity analysis by nitrogen adsorption. Results showed low surface area for Na-A zeolite in sodium form, but a higher one in CaA based on the nitrogen accessibility. The presence of cubic crystals for the A phase was observed in the SEM micrographies. The new procedure starting from natural clay favors the formation of sodalite while that using the calcinated clay gives A.

Aproveitamento sustentável de biomassa e de recursos naturais na inovação química

Increased production of biomass is currently the only immediately accessible alternative for large-scale carbon sequestration and it can produce large amounts of food, fuel and raw materials for the chemical industry that can in turn growingly replace oil as a source of organic building blocks and also of hydrogen and sulfur. Development of processes for biomass and abundant minerals transformation into chemical raw materials should now benefit from large inputs from nanotechnologies, biotechnologies, information and micro-reactor technologies. Success in R&D&Innovation along this line can yield new products and processes needed to perform desirable functions within a sustainable development paradigm.

Fontes vegetais naturais de antioxidantes

Growing knowledge on the health-promoting impact of antioxidants in everyday foods, combined with the assumption that a number of common synthetic preservatives may have hazardous side effects has led to increased investigations in the field of natural antioxidants, principally those found in plants. Food industries normally discard plant residues that could benefit the human health and diminish undesirable environmental impact. Once estimated the content of antioxidants in these residues, advantageous economical and social alternatives to the discard are possible, for example, their use for preparation of nutraceuticals to be offered to low-income populations. We present here a broad, although not complete, account of the continuously growing knowledge on the antioxidant capacity of whole fruits, seeds and peels, cereals, vegetal oils and aromatic plants, at several physical forms, as well as a description of the usual methods for evaluating their antioxidant capacity and examples of agroindustrial processes that could be harnessed for the production of antioxidant supplement food, along with research perspectives in the area.

Fotoprotetores derivados de produtos naturais: perspectivas de mercado e interações entre o setor produtivo e centros de pesquisa

Ultraviolet radiation is the major exogenous mediators of skin damage. To prevent such damage, sunscreen products are used. New research aims at both the elucidation of new sunscreen compounds, as well as new assets for supporting and synergistic action. In this article it is presented a systematic data of innovation for sunscreen and a discussion on prospects for partnership between universities and enterprises, where it is believed that the innovations in cosmetics, driven by the constant demand of the market in new products, may be a stimulus for the interactions between university and company in Brazil.

Remoção de Pb2+ e Cr3+ em solução por zeólitas naturais associadas a rochas eruptivas da formação serra geral, bacia sedimentar do Paraná

The capacity of natural zeolites and its host rock (dacite) to remove Pb2+ and Cr3+ from aqueous solutions has been investigated. Results showed that both samples prefer to remove Pb2+ instead of Cr3+. Almost 100% of Pb2+ was removed from solutions with concentration until 50 mg L-1 and 100 mg L-1 of this metal, respectively by dacite and zeolite. The equilibrium of metals adsorption process was reached during the first 30 min by both materials. Na+ can be used to recover Pb2+, but not to remove Cr3+ from the treated samples. The Sips model showed a good fit for experimental data of this study.

Alucinógenos naturais: um voo da Europa Medieval ao Brasil

This work describes the historical importance and the use of hallucinogenic plants by different civilizations. A comparison between three Brazilian plants whose active principle is N,N-dimethyltriptamine (DMT), and three plant species native to Europe whose active principles are tropanic alkaloids was carried out and we observed these plants promoted different types of hallucinations.

Emissões naturais e antrópicas de metais e nutrientes para a bacia inferior do rio de contas, Bahia

Emission factors of anthropogenic activities and natural processes were used to estimate nutrients and metals loads to the Contas River lower basin, Southern Bahia, Brazil. Among natural sources, emission from soil leaching is larger for N, Cu and Pb. Atmospheric deposition is the major natural source of P, Zn, Cd and Hg. Among anthropogenic sources, agriculture is the major source of N, Cu and P. Urban sources are the major contributors to the other elements. Present anthropogenic land uses are already responsible for 78 and 99% of total N and P loads and about 50% of total Cu and Hg.

Sistema limpo em linha para extração em fase sólida de contaminantes emergentes em águas naturais

A solid-phase in-line extraction system for water samples containing low levels of emerging contaminants is described. The system was specially developed for large volume samples (up to 4 L) using commercial solid-phase extraction (SPE) cartridges. Four sets containing PTFE-made connectors, brass adapters and ball valves were used to fit SPE cartridges and sample bottles to a 4-port manifold attached to a 20 L carboy. A lab-made vacuum device was connected to the manifold cap. The apparatus is robust and less expensive than the typical available system. Its also provides less experimental handling, avoiding cross contamination and sample losses.

Em busca da sustentabilidade: células solares sensibilizadas por extratos naturais

The present work reports the use of anthocyanins extracted from mulberry (Morus Alba L.), raspberry (Rubus Idaeus L.) and blueberry (Vaccinium myrtillus L.) as sensitizers in dye-sensitized solar cells. The conversion efficiency of these devices is dependent on the extracts employed and can be rationalized in terms of their composition and spectral properties. Solar cells sensitized by the mulberry extract showed the highest efficiency among the fruits investigated. Moreover, a 16 cm² active area solar cell with the mulberry extract has presented fair good efficiency of conversion for natural dye-based solar cells, besides stability over twenty weeks, showing perspectives for developing these low cost devices with a commercial viability.

Estrogênios em águas naturais e tratadas da região de Jaboticabal - São Paulo

The aim of this work was to analyze 17 β estradiol and estrone, natural estrogenic hormones present in domestic effluents and animal excreta, in the public water supply system of Jaboticabal, SP. The results have shown the presence of estrogens in 22% of the samples in concentrations from 6,8 ng L-1 (treated water) to 30,6 ng L-1 (riverhead) for 17 β estradiol and 600 ng L-1 of estrone (stream), respectively. We concluded that animal wastes, discharges from the wastewater treatment station, and discharges of domestic effluent without treatment from rural proprieties were probably the cause of this contamination.