Lipases de látex vegetais: propriedades e aplicações industriais

Biocatalysts have innumerous advantages with respect to classical chemical processes, such as high specificity. Lipases (EC 3.1.1.3) are biocatalysts with large application in synthesis and hydrolysis reactions of triacylglycerols. The search for new sources of lipases has been intensified in the last years due to the high cost of microbial and animal lipases, wich restricts their use on an industrial scale. Lipases obtained from the latex of Carica papaya, Carica pentagona, Euphorbia characias, E. wulfenii, known for their proteolytic properties, are a good alternative source. In this review, we describe the well-known sources of vegetal lipases extracted from the latex and present some of their industrial applications.

Os produtos naturais e a química medicinal moderna

Natural products have been utilized by humans since ancient times and the relief and cure of their diseases was the first purpose for using natural products in medicine. The history of the oriental and occidental civilizations is very rich in examples of the utilization of natural products in medicine and health care. Chinese traditional medicine is one of the most important examples of how natural products can be efficient in the treatment of diseases, and it points to the importance of scientific research on natural products, concerning the discovery of new active chemical entities. The complexity, chemical diversity and biological properties of natural products always fascinated people, and during the last 200 years, this led to the discovery of important new drugs. In the last 30 years, the development of new bioassay techniques, biotechnology methods, bio-guided phytochemical studies, automated high throughput screening and high performance analytical methods, have introduced new concepts and possibilities of rational drug design and drug discovery. In this context, natural products have played an important and decisive role in the development of modern medicinal chemistry.

O inacreditável emprego de produtos químicos perigosos no passado

This work describes an overview of the use of chemicals in several commercial applications along the XXth century. The use of chemicals by men was largely empirical for many centuries, since there was no organized chemical and toxicological knowledge. During the XIXth century the chemical industry gained a crucial role in the development of technology, as evidenced by the extraordinary increase of new products and their incorporation into everyday life. Chemistry was considered a science capable of solving any problem, little regard being paid to the consequences of the widespread use of new chemicals. Efficiency was more important than safety and consumer information. From tragedies and the development of knowledge on toxicology men adopted more careful protocols before a new chemical was proposed for use. Modern life could not exist without the large-scale employment of a variety of chemicals but information on their responsible and conscious use is now essential. Products that were once considered the "last word in technology" have eventually proven dangerous to humans and the environment in the short or long time range. Previous knowledge on the toxicological dangers and the properties of a given substance or product before commercialization is necessary for safe handling.

Espectroscopia de Ressonância Magnética Nuclear de 13C no estudo de rotas biossintéticas de produtos naturais

During the last five decades, as a result of an interaction between natural product chemistry, synthetic organic chemistry, molecular biology and spectroscopy, scientists reached an extraordinary level of comprehension about the natural processes by which living organisms build up complex molecules. In this context, 13C nuclear magnetic resonance spectroscopy, allied with isotopic labeling, played a determinant role. Nowadays, the widespread use of modern NMR techniques allows an even more detailed picture of the biochemical steps by accurate manipulation of the atomic nuclei. This article focuses on the development of such techniques and their impact on biosynthetic studies.

Desenvolvimento e validação de metodologia analítica para determinação de itraconazol em produtos farmacêuticos por CLAE

Itraconazole is a synthetic antifungal drug administered orally with a broad spectrum of activity against mycotic infections. The present work consists of the development and validation of analytical methodology for evaluation of itraconazole in pharmaceutical products by high performance liquid chromatography. The separation was made using the reversed-phase column LC-18, acetonitrile/diethylamine 0.05% v/v, 60:40 v/v, pH 8.0 as mobile phase, methanol as solvent and detection and quantification at 254 nm. The results here obtained show that the analytical methodology is accurate, reproducible, robust and linear over the concentration range 8.0-12.0 µg/mL of itraconazole. The method was applied to pharmaceutical capsules containg itraconazole pellets and showed to be efficient, yielding good results.

Caracterização dos produtos líquidos e do carvão da pirólise de serragem de eucalipto

This study proposes the low temperature pyrolysis as an alternative conversion process for residual biomass and for obtaining gaseous, liquid and solid chemical feedstocks. Using a bench electrical pyrolysis oven, four product fractions from eucalyptus sawdust were obtained: a gaseous one, two liquid (aqueous and oily), and a solid residue (char). These products were characterized by different analytical methods. The liquid fractions showed themselves as potential sources for input chemicals. The residual char revealed appreciable adsorption capability. The process demonstrated good efficiency, generating at least two fractions of great industrial interest: bio oil and char.

Isolamento e atividades biológicas de produtos naturais das esponjas monanchora arbuscula, aplysina sp. petromica ciocalyptoides e topsentia ophiraphidites, da ascídia didemnum ligulum e do octocoral carijoa riisei

The investigation of extracts from six species of marine invertebrates yielded one new and several known natural products. Isoptilocaulin from the sponge Monanchora aff. arbuscula displayed antimicrobial activity at 1.3 mg/mL against an oxacillin-resistant strain of Staphylococcus aureus. Five inactive known dibromotyrosine derivatives, 2 6, were isolated from a new species of marine sponge, Aplysina sp. The sponges Petromica ciocalyptoides and Topsentia ophiraphidites yielded the known halistanol sulfate A (7) as an inhibitor of the antileishmanial target adenosine phosphoribosyl transferase. The ascidian Didemnum ligulum yielded asterubin (10) and the new N,N-dimethyl-O-methylethanolamine (11). The octocoral Carijoa riisei yielded the known 18-acetoxypregna-1,4,20-trien-3-one (12), which displayed cytotoxic activity against the cancer cell lines SF295, MDA-MB435, HCT8 and HL60.

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.

Transesterificação de óleos vegetais: caracterização por cromatografia em camada delgada e densidade

We studied the transesterification of two vegetable oils: soybean and waste frying oil. The main problem of transesterification is related to the measurement of the ethyl ester content. In this work we used a quick analytical method for assessing the ethyl ester fraction of the purified fuel-grade transesterification products by applying a simple correlation with density. If the ester content is higher than 85% by weight the correlation allows the determination by a single density measurement. This method is suitable for control and determines the ethyl ester quickly and simply.

Estudo comparativo de técnicas de screening para avaliação da atividade anti-bacteriana de extratos brutos de espécies vegetais e de substâncias puras

In this work, the effectiveness of four screening techniques (three techniques of the diffusion method and one microdilution broth method) were compared. Evaluated were the ethanolic and dichloromethanic extracts of Miconia rubiginosa (Melastomataceae) against six standard bacteria (ATCC). The results showed statistical disagreement among the three diffusion techniques. Among the diffusion techniques, the well technique displayed the best result. However the microdilution broth method demonstrated to be the most adequate method to evaluate the antibacterial activity of plant crude extracts and pure compounds when compared to the other methodologies.

Determinação voltamétrica de ciclamato de sódio em produtos dietéticos empregando um eletrodo de diamante dopado com boro

The use of square-wave voltammetry in conjunction with a cathodically pre-treated diamond electrode for the analytical determination of sodium cyclamate is described. The samples were analyzed as received in a 0.5 mol L-1 H2SO4 solution in the concentration range from 5.0 × 10-5 mol L-1 to 4.1 × 10-4 mol L-1, with a detection limit of 4.8 × 10-6 mol L-1. The RSD was smaller than 1.2 % and the proposed method was applied with success in the determination of sodium cyclamate in several dietary products.

Desenvolvimento de um procedimento biamperométrico para determinação de sacarina em produtos dietéticos

In this work was developed a method for the determination of saccharin in dietary products by a biamperometric titration, using two silver electrodes as working electrodes and silver nitrate as titrant. It were used products as juices (light) and sweeteners with saccharin in concentrations ranged from 8.73 x 10-5 mol L-1 to 1.0 x 10-2 mol L-1, and the results were in close agreement with those data found using a HPLC method at a confidence level of 95%. The main advantages of the proposed method are its simplicity, rapid and low cost.

Co-produção de lipase e biossurfactante em estado sólido para utilização em biorremediação de óleos vegetais e hidrocarbonetos

Recently lipases have been increasing in prominence due to its wide industrial application. The lipase production can be influenced by different variables such as the producing microorganism, carbon sources, aeration and agitation conditions, inductor type and the geometry of the reactor. Biosurfactants are composites of surface active produced by microbial cells which reduce superficial and interfacial tensions. The objective of this study was to verify the influence of different process variables in the lipase production during a fermentative process. The results showed that the concomitant production of lipases and biosurfactant was possible in different cultivation conditions.

Gliceroquímica: novos produtos e processos a partir da glicerina de produção de biodiesel

Glycerol is a byproduct of biodiesel production through transesterification of oils and fat. This article discusses the chemical transformation of glycerol in ethers, acetals and esters of high technological applications, especially in the fuel sector. Glycerol hydrogenolysis, dehydration to acrolein and oxidation are discussed as well, to show the potential use of glycerol for production of plastic monomers. Finally, the article shows other transformations, such as syn gas production, epichloridrin and glycerin carbonate.

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.