Alberto dos Santos Pereira

Flavonoids and trypanocidal activity of Bulgarian propolis

Acetone and ethanol extracts of two Bulgarian propolis samples (Bur and Lov) were investigated by high temperature high resolution gas chromatography coupled to mass spectrometry (HT-HRGC-MS), and their activity against Trypanosoma cruzi was evaluated. The ethanol extracts--Et-Bur and Et-Lov--showed similar composition, with a high content of flavonoids, and strong inhibitory activity against T. cruzi proliferative epimastigotes, which were more susceptible than trypomastigotes. In the presence of blood, the activity of Et-Bur or Et-Lov against trypomastigotes was similar to that of the standard drug, crystal violet. Both extracts also showed similar and significant activity against Staphylococcus aureus and Candida albicans, while being inactive against Escherichia coli. The acetone extract, Ket-Bur, was more active than Et-Bur against both forms of T. cruzi.

Própolis: 100 anos de pesquisa e suas perspectivas futuras

Propolis is a multifunctional material used by bees in the construction and maintenance of their hives. The chemical composition and pharmacological properties have been studied for centuries. Today they represent an important raw material for many health products and constitute a new interdisciplinary area for research. Among others they show important antimicrobial and cytotoxic activities and various pharmacological properties. This paper presents an overview of the scientific literature and patents concerning propolis.

Characterization of indoor air quality in the cities of sao paulo and rio de janeiro, Brazil.

Levels of several gas- and particle-phase substances present in indoor air in nonindustrial office workplaces and in restaurants was acquired during the Southeastern Brazil lndoor Air Quality Study (SEBIAQS) carried out in the summer of 1993. Simultaneous indoor and outdoor samples collected in 12 sites in the cities of Sao Paulo and Rio de Janeiro and in a rural area were analyzed for inhalable particulate matter (IPM dp < 15 µm), inhalable volatilizable particulate organic carbon, black (soot) carbon, trace metals, UV-RSP (d_(50) < 3.5 µm) as a marker for environmental tobacco smoke (ETS), formaldehyde, acetaldehyde, carbon monoxide, and nicotine. Indoor levels were generally higher. Alcohol-fueled vehicle emissions contributed to indoor acetaldehyde. The major sources of trace elements indoors and outdoors were respectively soil dust and combustion, resuspension, and vehicles. Dry deposition indoors was observed for S (mainly sulfate), AI, Fe, and Mn.

Characterization of organic pollutants in industrial effluents by high-temperature gas chromatography-mass spectrometry

Abstract The characterization of complex mixtures of organic contaminants present in industrial effluents is a well-known problem. The determination of individual target analytes depends very much on the analytical method used. In this article, the possibilities of using high-temperature gas chromatography–mass spectrometry (HT-GC–MS) are explored. In HT-GC–MS non-polar and medium-polarity phases can be operated at temperatures up to 370–420°C, allowing the analysis of high-molecular-weight compounds. So far, the applications of HT-GC have included the analysis of hydrocarbons up to C-100, lipids, sugars, and polyglycerols, but no data have been reported on the characterization of organic pollutants present in industrial effluents. The general sample handling approach reported here is based either on a sequential solid-phase extraction (SSPE) procedure, with a change of solvent composition in the elution from two different cartridges (C18 and Lichrolut EN), or on a toxicological fractionation. Effluent samples from tanneries, petrochemical plants, and textile industries are characterized, and the levels of the main organic pollutants identified are indicated. More than 50 compounds, including n-alkanes, phthalates, esters, acids, and phenols, were identified in the effluents studied.

Improvement in steroid screening for doping control with special emphasis on stanozolol

The Medical Commission of the International Olympic Committee forbids the use of anabolic androgenic steroids and beta2-agonists to improve athletic performance. In this work we have selected examples of anabolic androgenic compounds and their metabolites to evaluate the GC-MS analysis of some trimethylsilyl derivatives. The aim is to set the best GC conditions to improve the detection within the whole range of analyte elution temperatures. The initial column temperature was changed to 105 or 140 degrees C followed by 40 degrees C min(-1) to 200 degrees C and then 15 degrees C min(-1) to 300 degrees C. Using 140 degrees C as the initial oven temperature it was possible to obtain narrower initial analyte distributions for the compounds that elutes at the beginning of the chromatogram as clenbuterol, mabuterol, epimethylenediol and norandrosterone, without loss of derivatized metabolites signal. Later. eluting analytes, such as the stanozolol metabolites, furazabol and oxandrolone were not affected. Temperatures below 140 degrees C. resulted in partial derivatization for some analytes mainly stanozolol related structures. Therefore evaluation of derivatization conditions as occurring in three steps, the vial, vaporization chamber and capillary column, was thoroughly assessed. The new program temperature improves the signal-to-noise ratio for some compounds and shows adequate resolution for endogenous compounds. Some of the difficult key separations necessary for doping control enforcement were also obtained with the proposed method.

Three series of high molecular weight alkanoates found in Amazonian plants.

Electron impact mass spectra were measured by high temperature high resolution gas chromatography-mass spectrometry (HT-HRGC-MS) for three homologous series of high molecular weight compounds present in the Amazonian plants Marupá (Simaruba amara) and Brazil nut (Bertholettia excelsa). Based on their mass spectra, the compounds were identified as three wax ester series of alpha-tocopherol (vitamin E), beta-tocopherol and phytol (2,6,10,14-tetramethylhexadec-14-en-16-ol). The interpretations are supported by high resolution mass spectrometry and GC retention indices of authentic standards.

Mass spectra of triterpenyl alkanoates, novel natural products

A series of high molecular mass pentacyclic terpenoid wax esters in smoke from biomass combustion were characterized by high-temperature, high-resolution gas chromatography–mass spectrometry. Based on their mass spectra, they are interpreted as being a series of triterpenyl fatty acid esters (e.g. α- and β- amyryl palmitate). The carbon chain length of the fatty acids ranges from 5 to 20. This interpretation is supported by retention indeces, molecular ions and typical fragments of pentacyclic triterpenoids. Essentially, the mass spectra are simple and composed of the molecular ion, M-CH3, M-fatty acid and fragments characteristic of the esterified triterpenoid moieties.

High-temperature high-resolution gas chromatography: breaching the barrier to the analysis of polar and high molecular weight compounds

Developments in stationary phase synthesis and capillary column technology have opened new perspectives in the analysis of high molecular weight compounds (≥600 Da) and thermolabile organic compounds by high-temperature high-resolution gas chromatography (HT-HRGC). Apolar and medium polarity gum phases can now be operated at temperatures up to 400–480°C, and are being used for the analysis of compounds including n-alkanes up to C100, lipids, oligosaccharides, industrial resins, polyglycerols, cyclodextrins, and porphyrins.

Application of High Temperature High Resolution Gas Chromatography to Crude Extracts of Propolis

The underivatized acetone and hexane fractions from propolis samples (predominant flora Citrus spp. and Vernonia polyanthes) were analyzed by HT-HRGC (high temperature high resolution gas chromatography) and HT-HRGC coupled to mass spectrometry (HT-HRGC-MS). Several compounds, including flavonoid aglycones, phenolic acids, and high molecular weight compounds were characterized in crude extracts by HT-HRGC-MS. HT-HRGC and HT-HRGC-MS were shown to be quick and informative tools for rapid analysis of crude extracts without need for prior derivatization and purification.

High temperature gas chromatography with a glass capillary column for the analysis of high molecular weight tracers in smoke samples from biomass burning

A custom-made glass capillary column coated with OV-1701-OH (88% methyl, 7% cyanopropyl, 5% phenylpolysiloxane) was used to analyze smoke samples from biomass combustion of different species of plants collected in the Amazon forest. CS2 was used as solvent in order to enhance the dissolution and analysis of the heavier molecular weight components. The performance of the column was monitored during the experiments and a moderate increase in activity was observed after taking the column to high analytical temperatures (390°C). Trennzahl values typically dropped 20–30% from 1.7/m to the average of 1.35/m. In general, the performance of the custom-made column was satisfactory and comparable to the commercial high temperature columns. The high temperature high resolution GC and GC-MS analyses revealed the presence of a number of high molecular weight components reported to occur in smoke aerosols for the first time. These components consisted of series of wax esters (long chain alcohols esterified with long chain fatty acids) with up to 58 carbon numbers, aliphatic hydrocarbons, triglycerides, triterpenyl esters (e.g. α- and β-amyryl stearate). Although other types of compounds were also detected, their complete structure elucidation solely by electron impact MS was not adequate and other techniques will be required.