Evolutionary steps in the reproductive biology of Annonaceae

Flowers of Annonaceae are characterized by fleshy petals, many stamens with hard connective shields and numerous carpels with sessile stigmas often covered by sticky secretions. The petals of many representatives during anthesis form a closed pollination chamber. Protogynous dichogamy with strong scent emissions especially during the pistillate stage is a character of nearly all species. Scent emissions can be enhanced by thermogenesis. The prevailing reproductive system in the family seems to be self-compatibility. The basal genus Anaxagorea besides exhibiting several ancestral morphological characters has also many characters which reappear in other genera. Strong fruit-like scents consisting of fruit-esters and alcohols mainly attract small fruit-beetles (genus Colopterus, Nitidulidae) as pollinators, as well as several other beetles (Curculionidae, Chrysomelidae) and fruit-flies (Drosophilidae), which themselves gnaw on the thick petals or their larvae are petal or ovule predators. The flowers and the thick petals are thus a floral brood substrate for the visitors and the thick petals of Anaxagorea have to be interpreted as an antipredator structure. Another function of the closed thick petals is the production of heat by accumulated starch, which enhances scent emission and provides a warm shelter for the attracted beetles. Insight into floral characters and floral ecology of Anaxagorea, the sister group of the rest of the Annonaceae, is particularly important for understanding functional evolution and diversification of the family as a whole. As beetle pollination (cantharophily) is plesiomorphic in Anaxagorea and in Annonaceae, characters associated with beetle pollination appear imprinted in members of the whole family. Pollination by beetles (cantharophily) is the predominant mode of the majority of species worldwide. Examples are given of diurnal representatives (e.g., Guatteria, Duguetia, Annona) which function on the basis of fruit-imitating flowers attracting mainly fruit-inhabiting nitidulid beetles, as well as nocturnal species (e.g., large-flowered Annona and Duguetia species), which additionally to most of the diurnal species exhibit strong flower warming and provide very thick petal tissues for the voracious dynastid scarab beetles (Dynastinae, Scarabaeidae). Further examples will show that a few Annonaceae have adapted in their pollination also to thrips, flies, cockroaches and even bees. Although this non-beetle pollinated species have adapted in flower structure and scent compounds to their respective insects, they still retain some of the specialized cantharophilous characters of their ancestors.

Contribuições recentes da reação de hidroformilação na síntese de produtos farmacêuticos: parte II

The hydroformylation reaction represents one of the most important C1-chemistry area in the chemical industry. This catalytic process, which has been developed up to now mainly to the production of commodities chemicals, has shown a remarkable potential for the preparation of several categories of specialty chemicals and in particular pharmaceutical compounds. Arylpropanoic acids, various amines containing aryl groups, and intermediates for the preparation of vitamins, carbocyclic and heterocyclic compounds and many other classes of organic molecules endowed with pharmacological activity are currently accessible in good-to-high yields through hydroformylation of selected olefinic substrates. The asymmetric hydroformylation is going to reach the stage of maturity and hence to contribute in solving many troublesome synthetic problems connected with the preparation of pharmacologically active compounds with very high enantiomeric purity. The present survey emphasizes the usefulness of synthesis gas as a starting material in fine chemistry, which is expected to be important for industry.

Estratégias para a obtenção de compostos farmacologicamente ativos a partir de plantas medicinais: conceitos sobre modificação estrutural para otimização da atividade

In the present paper we discuss, based in our experience, some experimental procedures which may be employed for isolation of active compounds from medicinal plants. We have also emphasized some insights about the way to obtain more active and selective compounds from natural products through structural modifications oriented for analysis of structure-activity relationships.

Ácido L-ascórbico: reações de complexação e de óxido-redução com alguns íons metálicos de transição

The strong reducing action of L-ascorbic acid (Vitamin C) are of fundamental interest in biochemical and related process. The oxidation of ascorbic acid by molecular oxygen and others oxidants are of fundamental importance, involving the intervention of transition metal ions as catalysts and the formation transition metal complexes of ascorbic acid as intermediates. The present article is intended to cover some aspects of the reactions of ascorbic acid and related compounds involving some transition metal ions.

Análise de naftoquinonas em extratos brutos de raízes de Zeyheria montana M. (bolsa-de-pastor)

Four naphthoquinones, lapachol, a-lapachone, dehydro-a-lapachone and 4-hydroxy-a-lapachone were isolated from the ethanol extract of Zeyheria montana M. roots (Bignoniaceae) and were identified by spectroscopic methods. These naphthoquinones, except 4-hydroxy-a-lapachone, were quantified by HPLC, in the crude ethanol extracts of Z. montana roots. The separation of lapachol, a-lapachone and dehydro-a-lapachone was achieved and these compounds were identified in the chromatograms by their retention times and by their on line UV-spectra. The quantification of the three naphthoquinones, in four different samples showed medium contents of 11,0 mg of lapachol, 6,1 mg of a-lapachone and 4,3 mg of dehydro-a-lapachone, in 100 mg of Z.montana roots.

Molecular mechanics application in inorganic Chemistry

The present paper is a review about basic principles of the molecular mechanics that is the most important tool used in molecular modeling area, and their applications to the calculation of the relative stability and chemical reactivity of organometalic and coordination compounds. We show how molecular mechanics can be successfully applied to a wide variety of inorganic systems.

A utilização do safrol, principal componente químico do óleo de sassafráz, na síntese de substâncias bioativas na cascata do ácido araquidônico: antiinflamatórios, analgésicos e anti-trombóticos

In this paper we describe the results of a research effort developed in Laboratório de Avaliação e Síntese de Substancias Bioativas (LASSBio, UFRJ) in the utilization of Brazilian abundant natural product, safrole (1), the principal chemical constituent of Sassafras oil (Ocotea pretiosa), as an attractive synthon to access different chemical class of bioactive compounds, as prostaglandins analogues, non-steroidal antiinflammatory agents and antithrombotic compounds.

Componentes voláteis do café torrado. Parte II. Compostos alifáticos, alicíclicos e aromáticos

This review is about the aliphatic, alicyclic and aromatic compounds (non-heterocyclic compounds) that are present in the volatile fractions of roasted coffees. Herein, the contents, aroma precursors and the sensorial properties of volatile phenols, aldehydes, ketones, alcohols, ethers, hydrocarbons, carboxylic acids, anhydrides, esters, lactones, amines and sulphur compounds are discussed. Special attention is given to the compounds of these groups that are actually important to the final aroma of roasted coffees.

Análise dos álcoois, ésteres e compostos carbonílicos em amostras de óleo fúsel

Analysis of alcohols, esters and carbonyl compounds were performed using HRGC and HPLC techniques in samples of fusel oils from three different Brazilian alcohol distilleries. High content of isoamyl alcohol (390 g.L-1), isobutyl alcohol (158 g.L-1), ethyl alcohol (28,4 g.L-1), methyl alcohol (16,6 g.L-1) and n-propyl alcohol (11,9 g.L-1) were found. These compounds represent 77 ± 8 % of the approximated weight of a liter of fusel oils. The obtained results show the feasibility of using fusel oils as low-cost raw material for the synthesis of chemicals.

Estudo de compostos orgânicos em lixiviado de aterros sanitários por EFS e CG/EM

The main purpose of this work was the qualitative study of organic compounds in landfill leachate. The samples were collected from a sanitary landfill located at Gravataí, a southern Brazilian city, that receive both, industrial and domestic refuse. The samples were submitted to solid phase extraction (SPE) with XAD-4 resin as the stationary phase. The instrumental analysis was performed by Gas Chromatography with a Mass Spectrometry Detector (GC/MSD). The compounds achieved in the SPE extracts were tentatively identified by the GC/MS library. It was found several oxygen and nitrogen compounds like carboxylic acids, ketones, amines and amides. Sulfur compounds and phthalate esters are also identified.

Reações de ortometalacão em piridinas

In this paper we describe a powerful methodology for the regiospecific construction of polysubstituted aromatic and heteroaromatic compounds. The DoM reaction (direct ortho-metalation) comprises the deprotonation in position ortho of a aromatic or heteroaromatic containing DMG (directed metalation group) by strong bases, normally an alkyllithium reagent, leading to an ortho-lithiated species. These species, upon treatment with electrophilic reagents, gives 1,2 disubstituted products.

Plantas do gênero Bauhinia: composição química e potencial farmacológico

Plants of the genus Bauhinia (Leguminosae) are widely distributed in most tropical countries and have been frequently used in folk medicine to treat several ailments, especially diabetes. In recent years, the interest in these plants has increased considerably in all world. This review shows the main chemical and pharmacological aspects of these plants. The studies carried out with the extracts and purified compounds from these plants support most of their reported therapeutic properties. It also gives an account of some compounds including terpenes, steroids and flavonoids that were isolated from the genus Bauhinia.

Preparação de compostos de alumínio a partir da bauxita: considerações sobre alguns aspectos envolvidos em um experimento didático

Aluminum metal and aluminum compounds have many applications in several branches of the industry and in our daily lives. The most important raw material for aluminum and its manufactured compounds is bauxite, a rock constituted mainly by aluminum hydroxides minerals. In this work, a didactic experiment aiming the preparation of alumina and potassium alum starting from bauxite is proposed for undergraduate students. Both compounds are of great commercial, scientific and historical interest. The experiment involves applications of important chemical principles such as acid-base and precipitation. Some chemical properties and uses of aluminum compounds are also illustrated.

Detecção de adulterações em produtos alimentares contendo leite e/ou proteínas lácteas

A critical review of the most relevant analytical methodologies for quality and authenticity control of dairy products and foods containing milk proteins is presented. Chromatographic, electrophoretic and immunological methods are used for: detection of cow's milk in ewe and goat milks, detection of whey added to milk, detection of caseins and/or whey proteins in non-lactic foods and study compounds resulting from milk proteins degradation. Techniques based on polimerase chain reaction are also suitable for detection of cow's milk on cheeses of ewe and goat milks.

Estratégia de simplificação molecular no planejamento racional de fármacos: a descoberta de novo agente cardioativo

In this article are described examples of the successful use of molecular simplification strategy in the discovery of new drugs from bioactive natural products and synthetic compounds. The discovery of a new cardiotonic derivative (37, 2-thienylidene-3,4-methylenedioxybenzoylhydrazine; LASSBio-294), efficiently synthesized from Brazilian natural product and structurally designed by molecular simplification of active pyridazinone compounds reported in the literature, is described. A brief description of the pharmacological profile of this new cardiotonic lead-compound, belonging to the N-acylhydrazone (NAH) class, is also reported herein.