F.R. Aquino Neto

Chemical composition and microbicidal activity of extracts from Brazilian and Bulgarian propolis

Aims:  The chemical composition of ethanol extracts from a Brazilian (Et‐Bra) and a Bulgarian (Et‐Blg) propolis, and their activity against the protozoan Trypanosoma cruzi, several fungi and bacteria species were determined.

Organic geochemistry of geographically unrelated tasmanites

Abstract The biomarker analysis of three tasmanite rock samples from Tasmania, Alaska and Brazil showed an unusually high tricyclic terpane concentration relative to hopanes and steranes. A possible product-precursor relationship is advanced, associating Tasmanaceae alage with these tricyclic terpanes. These results support the search of possible precursor molecules in present day organisms which may be taxonomically related to these algae.

Analysis of phytoestrogens, progestogens and estrogens in environmental waters from Rio de Janeiro (Brazil).

The environment is currently exposed to a large variety of man-made chemicals (e.g. for industrial, medicinal use) which have potential adverse effects to its ecological status. In addition, the densely populated areas represent local high emissions of those chemicals leading to more aggravating consequences. Estrogenic compounds that end-up in environmental water directly affect living organisms by interfering with their endocrine metabolism. The assessment of their presence in the environment requires sensitive and selective analytical methods. Nineteen estrogenic compounds belonging to different classes (5 free estrogens, 6 conjugated estrogens, 3 progestogens and 5 phytoestrogens) have been studied. The analytical methodology developed is based on solid phase extraction followed by liquid chromatography tandem mass spectrometry and has been applied to study the occurrence of the above mentioned analytes in environmental waters from the state of Rio de Janeiro (Brazil). Due to insufficient infra-structure in this region, waste waters are released onto the environment without or with incomplete previous treatment. The results show that high levels of the phytoestrogens daidzein, coumestrol and genistein of up to 366 ng/L and progesterone of up to 47 ng/L could be found in river water. Estrogens and their conjugated derivatives were detected in the lower ng/L range up to 7 ng/L. The main estrogens estrone, estradiol and the synthetic ethinyl estradiol could not be detected. The developed method showed overall good performance with recoveries above 80% (with one exception), limits of detection < or =2 ng/L, good linearity and reproducibility.

Extended tricyclic terpanes in sediments and petroleums

An extended series of tricyclic terpanes was identified in sediments and petroleums from Brazil. The identification of the tricyclic terpanes was based on their chromatographic behavior and characteristic MS/MS transitions from molecular ions to m/z 191. We identified tricyclic terpane homologs up to C54. The presence of this extended series, from C19 up to C54, varies considerably with depositional environment, being prominent in saline lacustrine and marine carbonate settings. This suggests that the biological precursor organism lived in moderate conditions of salinity.

Composition of green coffee water-soluble fractions and identification of volatiles formed during roasting

Flavour precursors from water-soluble green coffee low molecular weight (B) and high molecular weight (C) fractions were investigated and the volatiles formed during roasting were identified by high resolution gas chromatography/mass spectrometry (HRGC/MS). Roasting promoted extensive degradation of trigonelline, sucrose and amino acids in fraction (B) and of arabinogalactan in fraction (C). The analyses of the roasted isolated fractions showed that furans are not only formed by sucrose degradation but also by arabinogalactan pyrolysis. Also, pyrazines appear to be mainly formed by pyrolysis of hydroxy amino acids from fraction (C). The results also showed that pyridine found in roasted coffee is not exclusively formed by trigonelline degradation but also by protein pyrolysis.

Novel series of tricyclic aromatic terpanes characterized in Tasmanian tasmanite

Abstract A novel series of tricyclic ring-C monoaromatic terpanes and a minor group of tricyclic diaromatic terpanes were characterized in Tasmanian tasmanite. The monoaromatic series ranges from C18 to C40, with a homolog distribution pattern similar to the geologically ubiquitous tricyclic terpane series. The diaromatic compounds are comprised of the C17-C19 homologs. The occurrence of these aromatic compounds in an immature sediment (Ro = 0.3–0.4%) indicates an early diagnetic origin or possibly a direct biological input. The implications of these findings to the search for the precursors of these biomarkers is discussed. A minor series of aromatic des-A-triterpenoid hydrocarbons from biodegraded terrestrial lipids is also present.

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.

Occurrence of four stereoisomeric tricyclic terpane series in immature Brazilian shales

We report the presence, in an immature Brazilian oil shale (Irati), of C19C26 tricyclic triterpanes, present as mixtures of stereoisomers. The C20 components have been identified by comparison with synthetic standards as 13β(H),14β(H); 13α(H),14β(H); 13β(H),14α(H) and 13α(H),14α(H) isomers. By extrapolation, all fourC21 homologues and the C23–C26,14α(H) and 13α(H),14α(H) isomers are also shown to occur. The geochemical significance of these findings is discussed.

TiO2-photocatalyzed degradation of phenol in saline media in an annular reactor: hydrodynamics, lumped kinetics, intermediates, and acute toxicity.

The photocatalytic degradation of phenol in aqueous suspensions of TiO2 under different salt concentrations in an annular reactor has been investigated. In all cases, complete removal of phenol and mineralization degrees above 90% were achieved. The reactor operational parameters were optimized and its hydrodynamics characterized in order to couple mass balance equations with kinetic ones. The photodegradation of the organics followed a Langmuir-Hinshelwood-Hougen-Watson lumped kinetics. From GC/MS analyses, several intermediates formed during oxidation have been identified. The main ones were catechol, hydroquinone, and 3-phenyl-2-propenal, in this order. The formation of negligible concentrations of 4-chlorophenol was observed only in high salinity medium. Acute toxicity was determined by using Artemia sp. as the test organism, which indicated that intermediate products were all less toxic than phenol and a significant abatement of the overall toxicity was accomplished, regardless of the salt concentration.

Uric acid changes in urine and plasma: An effective tool in screening for purine inborn errors of metabolism and other pathological conditions

SummaryPurine inborn errors of metabolism (IEM) are serious hereditary disorders, which should be suspected in any case of neonatal fitting, failure to thrive, recurrent infections, neurological deficit, renal disease, self-mutilation and other manifestations. Investigation usually starts with uric acid (UA) determination in urine and plasma. UA, the final product of purine metabolism in humans, may be altered not only in purine IEM, but also in other related pathologies and clinical conditions. However, data and information about abnormal UA levels are scattered in the literature, often being controversial and confusing. A comprehensive overview has been elaborated, according to abnormal UA levels in urine and plasma, which associates these alterations with purine IEM. Other possible diseases, clinical conditions, diet and drug intake, related to the metabolism of uric acid, are also presented. The article includes tables that classify the disorders according to different patterns of UA alterations, with pertinent enzymes, clinical symptoms, inheritance and comments. Additionally, summarized pathophysiological mechanisms of important disorders are described. The overview is intended to assist in the interpretation of the results of UA analyses. It demonstrates that variation of UA concentrations in urine and plasma may constitute an effective tool in screening for purine IEM and other related pathological conditions.