Composição química de óleos essenciais de espécies de Aniba e Licaria e suas atividades antioxidante e antiagregante plaquetária

Leaves and stems from Aniba panurensis (Meisn.) Mez, Aniba rosaeodora Ducke and Licaria martiniana (Mez) Kosterm. were collected in the Reserva Florestal Adolpho Ducke-AM and their essential oils were obtained by hydrodistillation procedures. The oils were analyzed by GC-FID and GC-MS resulting on fifty and six compounds being identified. The major components were linalool in A. rosaeodora, and β-caryophyllene in A. panurensis and L. martiniana. At qualitative assays the oils showed antioxidant and antiplatelet activities, but only weak activities were found at quantitative spectrometric assays.

Óleos essenciais das folhas de Vernonia Remotiflora e Vernonia Brasiliana: composição química e atividade biológica

The chemical composition of the essential oils, obtained by hidrodistillation, from leaves of two Vernonia species (V. remotiflora and V. brasiliana), was determined by GC-FID and GC-MS. Both essential oils were predominantly constituted by sesquiterpenes (92.0 - 93.4%). The main constituents of the oil from V. brasilana were (E)-caryophyllene (36.7%), germacrene D (35.5%), and α-humulene (11.7%), while (E)-caryophyllene (42.2%) and bicyclogermacrene (20.0%) were the major ones in the oil from V. remotiflora. Although with moderate activity both oils showed acetylcholinesterase and antibacterial activities.

Determinação de metais em óleos lubrificantes, provenientes de motores de ônibus urbano, utilizando a FAAS

This work proposed a procedure to examine ashes produced in burning lubricating oils used in public transportation, in Teresina PI. Sulphanilic acid was added to the oil samples, which were burned at 550 °C for three hours and 650 °C for two hours. The ash solutions were analyzed by FAAS and there were significant differences in the metal contents of the waste oil produced from normal car service. The quantification limits in μg g-1 were 5.9 (Fe), 4.4 (Pb), 1.7 (Ni), 2.1 (Cu), and 1.2 (Zn). The results showed positive accuracy and precision with recoveries between 88 and 108%, and RSD lower than 10%.

Determinação de enxofre em amostras vegetais por oxidação via seca em meio alcalino com detecção espectrofométrica

The sulphur take an essential role in plants and it is one of the main nutrients in several metabolic processes. The dry ash oxidation, using alkaline oxidizers agent, is the simplest and most economical form for the oxidation of Organic S to sulfate in plants. The objective of this work is to propose a method for sulfur determination in plants samples using dry ash oxidation and agent oxidizers alkaline. The quantification of S-SO4(2-) in samples was accomplished by turbidimetric method. The results demonstrated that the proposed method for oxidation alkaline was appropriate.

Avaliação geoquímica de óleos brasileiros com ênfase nos hidrocarbonetos aromáticos

Aromatic compounds are still poorly evaluated in geochemical studies of Brazilian oil samples. For this reason, the objective of this work was to analyze and evaluate 26 oil samples from four Brazilian sedimentary basins. Aromatic hydrocarbon fractions have been analyzed by gas chromatography coupled to mass spectrometry. The results were also compared with previously evaluated saturated hydrocarbon data. Maturation parameters obtained using the 4- and 1-methyl-dibenzothiophenes and trimethyl-dibenzothiophenes led to the best results because a better grouping was observed. For this correlation, the samples were grouped by maturity degree enabling the routine use of these parameters to evaluate oil maturity levels.

Antocianinas em extratos vegetais: aplicação em titulação ácido-base e identificação via cromatografia líquida/espectrometria de massas

Anthocyanins extracted from picao, quaresmeira, petunia, flamboyant, purple ipe, lobeira, pata de vaca, jaboticaba, purple cabbage and jambul were evaluated as natural acid-base indicators. Anthocyanins in extracts were identified using HPLC/MS. Clear, rapid change in color at final-point titration was observed for extracts but only picao showed strong change in pH. Indirect determination of carbonate in limestone using a natural indicator was performed and results compared with phenolphthalein indicator and potentiometer titration. Optimal results were obtained with picao but other extracts showed good accuracy and precision.

Efeitos das condições ambientais sobre o teor e variabilidade dos óleos voláteis de dalbergia frutescens (Vell.) Britton (Fabaceae)

The volatile oils of Dalbergia frutescens were obtained by hydrodistillation on a Clevenger-modified apparatus for every month of one year and assessed on GC/MS and GC/FID detectors for qualitative and quantitative analyses. The influence on content of volatile oils was directly proportional to the environmental variables, temperature and cloudiness, and inversely proportional to precipitation. Among the volatile compounds detected, linalool, β-damascenone, α-ionone, geranyl acetone and β-ionone were the main components, of which β-damascenone and β-ionone were found at the highest concentrations.

Análise forense: pesquisa de drogas vegetais interferentes de testes colorimétricos para identificação dos canabinoides da maconha (Cannabis Sativa L.)

Marijuana (Cannabis sativa L.) is the most cultivated, trafficked and consumed illicit drug worldwide. Estimates indicate 10% of individuals experiencing marijuana become daily users, and 20-30% use it weekly. Around 489 natural compounds have been identified in this plant, of which 70 are cannabinoids, responsible for psychic effects. The most relevant cannabinoid is Δ9-THC, recognized as the main chemical substance with psychoactive effects. The aims of this work was to investigate whether other drugs interfere with the colorimetric tests Fast Blue B and Duquenois-Levine, widely used for marijuana screening in forensic chemistry laboratories.

Avaliação da estabilidade oxidativa do óleo bruto de açaí (Euterpe oleracea) na presença de compostos fenólicos puros ou de extratos vegetais amazônicos

A final 241 µM of ascorbyl palmitate and 555 µM of the following antioxidants separately: BHA, myricetin and quercetin standards, and extracts of Byrsonima crassifolia, Inga edulis or Euterpe oleracea, were added to crude açai oil and submitted to the oxidation process at 60 ºC for 11 days. Among the antioxidants used, only the myricetin standard showed the ability to defer the oxidation process until the third day of treatment. B. crassifolia, I. edulis and E. oleracea extracts showed no preventive capacity against the oxidation process, despite their high concentration phenolic compounds and antioxidant activities.

Cor ASTM: um método simples e rápido para determinar a qualidade do biodiesel produzido a partir de óleos residuais de fritura

In this study, 23 biodiesel samples were produced, 20 from used cooking oil and the remaining 3 from refined soybean oil. The following properties were determined in all of the samples (oil and its respective biodiesel): density; viscosity; total acid number and ASTM color. The results indicated high correlation (R > 0.6) between ASTM color of used cooking oil and total acid number of its resultant biodiesel. This high correlation allows prediction of the quality of the biodiesel produced using a simple and fast procedure such as ASTM color.

Obtenção de biodiesel por transesterificação em dois estágios e sua caracterização por cromatografia gasosa: óleos e gorduras em laboratório de química orgânica

Methanolic transesterification of oils and fats was carried out in a two steps procedure, under basic and acidic catalysis. Palm, soybean, canola, corn, rice, grapeseed, sunflower, peanut, pequi and olive oils, besides tallow and lard were used as feedstock. Specific gravity, relative viscosity, thin layer chromatography and gas chromatography were used to characterize the biodiesel. Biodiesel was obtained in high yield and purity. Results were used to discuss the following key-concepts: 1 - triglycerides, composition and properties; 2 - nucleophilic acyl substitution under basic and acid conditions, 3 - thin layer chromatography, 4 - gas chromatography and its quantitative methods.

Atividades biológicas dos óleos essenciais de Endlicheria citriodora, uma lauraceae rica em geranato de metila

The essential oils of branches and leaves of Endlicheria citiodora were obtained by hydrodistillation and analysed using GC-FID, GC-MS and both NMR 13C and ¹H, resulting in the identification of methyl geranate as major constituent (93%) in both oils. Cytotoxicity, tyrosinase-inhibition and antioxidant activities were studied and characterized. High antioxidant potential (15.52 and 13.53 µg/mL), low cytotoxicity and tyrosinase inhibition (53.85%) were observed. This is the first paper reporting the biological activities and composition of the essential oils of this species.

Chumbo e cádmio detectados em alimentos vegetais e gramíneas no município de Santo Amaro-Bahia

This study evaluated the level of the metals Pb mg kg-1 and Cd mg kg-1 found in plant species and the contribution of the levels detected in contaminated soils located in the urban area of the city of Santo Amaro, Bahia. Levels were determined by graphite furnace and flame atomic absorption spectrometry. The results showed the presence of Pb and Cd in plant species at levels ranging from 0.18 to 118.2 mg kg-1 and 0.04 to 7.29 mg kg-1, respectively. The concentration values obtained varied according to the plant species and were not strongly influenced by the concentration values detected in the soil.

Atividade inseticida de óleos essenciais de Pelargonium graveolens l'Herit e Lippia alba (Mill) N. E. Brown sobre Spodoptera frugiperda (J. E. Smith)

Insecticidal activity of essential oils of Pelargonium graveolens, Lippia alba and compounds geraniol, linalool, 1,8-cineole, limonene, carvone, citral and Azamax® were evaluated against Spodoptera frugiperda. Topical application assay showed essential oil of P. graveolens has acute toxicity against Spodoptera frugiperda larvae (third instar) with LD50 1.13 µg/mg per insect and LD90 2.56 µg/mg per insect. Three essential oils of L. alba also exhibited insecticidal activity with LD50 ranging from 1.20 to 1.56 µg/mg per insect and LD90 from 2.60 to 3.75 µg/mg per insect. Geraniol, linalool, carvone and citral caused significant mortality of 30, 90, 84 and 64% respectively, compared to negative control. The bioinsecticide, Azamax®, caused lower mortality than the compounds of the essential oils.

Caracterização físico-química de resíduos oleosos do saneamento e dos óleos e graxas extraídos visando a conversão em biocombustíveis

Oily waste from sanitation processes was characterized for its potential use in the generation of biofuels. The waste residues studied showed high levels of oil and grease, reaching up to 87% (m/m) in a grease trap of a food company, showing that these residues can be utilized for the production of biofuels. The results revealed high levels of moisture and saponification as well as high levels of free fatty acids (FFA). Analysis of chromatographic profiles (HPLC) showed great heterogeneity of the fatty acids contained in the sample, and a predominance of palmitic, oleic, linoleic and linolenic acids.