Concentrations, sources and risks of polycyclic aromatic hydrocarbons in sediments from the Parnaiba Delta basin, Northeast Brazil.

The Parnaíba River is the main river in the Parnaíba Delta basin, the largest delta in the Americas. About 18 polycyclic aromatic hydrocarbons (PAHs) were identified and the environmental risk associated with the sediments was evaluated. The study found that PAHs levels ranged from 5.92 to 1521.17 ng g-1, which was classified as low to high pollution, and that there were multiple sources of pollution along the river, with pyrolytic sources predominating, mainly from urban activity such as trucking, although the influence of rural activity cannot be ruled out. PAHs correlated with black carbon and organic matter and showed high correlation with acenaphthylene, phenanthrene, pyrene, benzo(a)anthracene, chrysene, benzo(ghi)perylene, and ∑PAHs. The benzo(a)pyrene levels were classified as a risk to aquatic life because the threshold effect level and the probable effect level were exceeded. In addition, the sediments were classified as slightly contaminated with a benzo(a)pyrene toxicity equivalent value of 108.43 ng g-1. Thus, the priority level PAH exhibited carcinogenic and mutagenic activity that posed a potential risk to human health.

Diastereoselectivity Switch During Alkene Reductions: Diastereodivergent Syntheses of Molecular Fossils via MHAT or Homogeneous Catalytic Hydrogenation Reactions.

Sixteen geosterane derivatives were synthesized in up to 57 % overall yields in four steps harnessing the olefin cross-metathesis (OCM) and Metal hydride H atom transfer (MHAT) or homogeneous hydrogenation reactions as key steps. Drawing on this strategy, the diastereomeric ratio (d. r.) reached up to 24 : 1 for the thermodynamic isomer and 7 : 1 for the other isomer in the hydrogenation step. In a geological sample from northeast Brazil, we confirmed the putative structures previously assumed as methyl 2-(3α-5αH-cholestan) acetate, methyl 2-(3ß-5αH-cholestan)acetate, and methyl 6-(3ß-5αH-cholestan)hexanoate, as well three new molecular fossils of approximately 120 million years old. We also proved the migration marking ability of those carboxylic acids derived from forerunner geosteranes during an oil migration event, which suggests their aptitudes as molecular odometers. Our approach demonstrated swiftness and effectiveness in preparing a molecular library of geological biomarkers would also be appropriate to generate stereochemical diversity in molecular libraries for medicinal chemistry and natural product anticipation.

Gas Chromatography-Triple Quadrupole Mass Spectrometry Analysis and Vasorelaxant Effect of Essential Oil from Protium heptaphyllum (Aubl.) March.

The Protium heptaphyllum species, also known as Almécega, produces an oily resin, used in folk medicine as an analgesic and anti-inflammatory agent, in healing, and as an expectorant, which is rich in pentacyclic triterpenes and essential oils. In this study, the essential oil obtained by hydrodistillation of Almécega's resin was analyzed by gas chromatography-triple quadrupole mass spectrometry and evaluated for chemical composition and vasorelaxant activity in rat superior mesenteric artery. The main constituents determined by gas chromatography-triple quadrupole mass spectrometry were limonene, p-cineole, and o-cymene. In intact rings precontracted with phenylephrine (Phe 1 µM), EOPh (3-750 µg/mL) induced relaxation, and the essential oil had a concentration-dependent vasorelaxant effect, without involvement of endothelial mediators.

Isolation, characterization and evaluation of antimicrobial and cytotoxic activity of estragole, obtained from the essential oil of Croton zehntneri (Euphorbiaceae).

Croton zehntneri (Euphorbiaceae) is a native aromatic plant from Northeast region of Brazil. The monoterpenoid estragole (ESL) has been isolated by classical chromatographic methods from the essential oil (EO) of C. zehnteneri leaves and characterized by GC-FID and GC-MS, its antimicrobial and cytotoxic potentials being assessed. The analysis of the EO enabled the identification of 100% of the integrated constituents, of which yield was about 1.8%. The main components identified were: eucalyptol, estragole (84.7%) and spathulenol. The dosage of 50 µg/disk of ESL presented fairly significant zones of inhibition against Gram-positive bacteria and fungi. The ESL presented toxicity against Artemia salina with LC50 and LC90 of 4,54 and 8,47 µg mL-1. However, in tumor inhibition assays (human cells), there were no rewarding inhibition in any of the human cancer cell lines (MCF-7, HEP-2 and NCI-H292).

Investigation of biological activities of dichloromethane and ethyl acetate fractions of Platonia insignis Mart. seed.

Platonia insignis Mart., a native species of the Brazilian Amazon more commonly known as bacuri, is a member of the Clusiaceae family. In this study, we evaluated the chemical composition and the antioxidant and toxicity activities of the dichloromethane and ethyl acetate fractions from P. insignis seed ethanolic extract using different experimental models. Our results demonstrate in vitro antioxidant effects, by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt and 1,1-diphenyl-2-picryl-hydrazyl assays, as well as in vivo effects in antioxidant-defective Saccharomyces cerevisiae strains to both fractions. Toxicity was evaluated against the micro-crustaceous Artemia salina Leach. and promastigote Leishmania amazonensis. The dichloromethane fraction was the most active fraction evaluated on A. salina and promastigote L. amazonensis (IC(50)  = 24.89 µg/mL and 2.84 µg/mL, respectively). In addition, a slight cytotoxicity was observed in mammalian V79 cells using ethyl acetate and dichloromethane fractions with MTT assays. Both fractions displayed genotoxicity up to 25 µg/mL (dichloromethane) and 10 µg/mL (ethyl acetate) in V79 cells, as evaluated by the alkaline comet assay. Thus, in this study, we demonstrate for the first time that ethyl acetate and dichloromethane fractions from P. insignis seeds display antioxidant effects, a toxic effect against A. salina and L. amazonensis and induce genotoxicity in V79 mammalian cells. The observed activities can be attributed to the phenolic compounds present in these fractions and to the presence of xanthones (alpha- and gamma-mangostin).

Chemical constituents and evaluation of cytotoxic and antifungal activity of Lantana camara essential oils

The essential oil (EO) of aerial parts of Lantana camara L., Verbenaceae, from Simões, Piaui, Northeast of Brazil, were obtained by hydrodistillation and analyzed by GC-FID and GC-MS techniques. In total, 68 compounds were identified. The most representative compounds of the oil were mono and sesquiterpenes. The main compounds found in the oil of the leaves in different months were β-caryophyllene (10.5%, in June of 2009), sabinene (7.98%, in September of 2008), limonene (7.68%, in September of 2008), spathulenol (11.64%, in September of 2008). The oil from stems of L. camara was characterized by a largest amount of sesquiterpenoids, with spatulenol (15.9%) and caryophyllene oxide (17.1% in June of 2009), as main components. β-Gurjunene (32.7%, in September of 2008) was the most prominent compound in the stems oils, which was absent or at very low relative abundance in leaves. L. camara essential oils from leaves were cytotoxic to V79 mammalian cells and also to Artemia salina, showing 50% lethal concentration (LC50) values from 0.23 µg/mL. The in vitro data obtained in this study suggested that EO may also be effective treating yeast infection in patients infected with fluconazole and terbinafine resistant isolates, but its toxicity must be monitored carefully.

Lantana montevidensis Briq improves the aminoglycoside activity against multiresistant Escherichia coli and Staphylococcus aureus.

OBJECTIVE: In this work, we report the antibacterial and modulatory activity of Lantana montevidensis Briq. MATERIALS AND METHODS: The antibacterial activities of leaf (LELm) and root (RELm) extracts alone or in association with aminoglycosides were determined by a microdilution test. Multiresistant strains of Escherichia coli (Ec 27) and Staphylococcus aureus (Sa 358) were used. RESULTS: The results show the inhibitory activity of LELm against E. coli (minimal inhibitory concentration [MIC] 16 µg/mL) and S. aureus (MIC 128 µg/mL). The synergistic effect of the extracts and aminoglycosides was verified too. The maximum effects were obtained with RELm with gentamicin against E. coli with MIC reduction (312 to 2 µL). CONCLUSION: The data from this study are indicative of the activity antibacterial of extracts of L. montevidensis and its potential in modifying the resistance of aminoglycosides.

Chemical composition and resistance-modifying effect of the essential oil of Lantana camara Linn.

In this work, the chemical constituents, antibacterial and modulatory activities of the essential oil of Lantana camara Linn were studied. The essential oil was extracted from the leaves of L. camara by hydrodistillation method using Clevenger's apparatus and its chemical constituents were separated and identified by GC-MS, and the relative content of each constituent was determined by area normalization. Among the 25 identified components, bicyclogermacrene (19.42%), isocaryophyllene (16.70%), valecene (12.94%) and germacrene D (12.34%) were the main constituents. The oil was examined to antibacterial and modulatory activities against the multiresistant strains of Escherichia coli and Staphylococcus aureus by microdilution test. The results show an inhibitory activity to E. coli (MIC 512 mug/ml) and S. aureus (MIC 256 mug/ml). The synergism of the essential oil and aminoglycosides was verified too, with significant reduction of MICs (7 x, 1250-5 mug/ml) against E. coli. It is suggested that the essential oil of Lantana camara Linn could be used as a source of plant-derived natural products with resistance-modifying activity.

Composição química e avaliação das atividades antibacteriana e de toxicidade dos óleos essenciais de Lantana camara L. e Lantana sp. / Chemical composition, evaluation of antibacterial activity and toxicity of the essential oils from Lantana camara L. and Lantana sp.

Os óleos essenciais de Lantana camara L. e Lantana sp., Verbenaceae, foram obtidos por hidrodestilação e seus componentes analisados por CG/EM. Tal procedimento analítico revelou a predominância dos sesquiterpenos, biciclogermacreno (19,42 por cento), isocariofileno (16,70 por cento), valenceno (12,94 por cento) e germacreno D (12,34 por cento) no óleo de L. camara, enquanto o biciclogermacreno (13,93 por cento), germancreno D (27,54 e β-cariofileno (31,50 por cento), por cento) destacaram-se como majoritários no óleo de Lantana sp. Os dois óleos foram submetidos a avaliação de atividades antibacteriana e de toxicidade usando as larvas de Artemia salina. Os resultados mostraram considerável atividade antibacteriana do óleo de L. camara, principalmente para Proteus vulgaris (ATCC 13315) e Escherichia coli (ATCC 25922). O óleo de Lantana sp. mostrou-se mais significativo contra Sthaphylococcus aureus (ATCC 10390). As atividades de toxicidade CL50 revelaram resultados inferiores ao limite padrão de 1000 μg/mL.

The essential oils from Lantana camara L. and Lantana sp. Verbenaceae, were obtained by hydrodistillation and analyzed by GC/MS. This GC/MS analysis revealed the sesquiterpenoids bicyclogermacrene (19.42 percent), isocaryophyllene (16.70 percent), valencene (12.94 percent) and germacrene D (12.34 percent) as majoritaries in the essential oil of L. camara, and bicyclogermacrene (13.93 percent), germacrene D (27.54 and β-caryophyllene (31.50 percent) in the essential oil from Lantana sp. The two essential oils were evaluated to antibacterial activity and toxicity using Artemia salina. The results revealed considerable antibacterial activity for essential oil from L. camara, meanly for Proteus vulgaris (ATCC 13315) and Escherichia coli (ATCC 25922). The essential oil of Lantana sp. showed major activity for Sthaphylococcus aureus (ATCC 10390). The evaluation of toxicity CL50 revealed results with minor values to limit pattern of 1000 μg/mL.