234 resultados para cerium compounds
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Two new compounds named illiverin A (1) and tashironin A (8) were, isolated from the roots of Illicium verum, together with seven known compounds: 4-allyl-2-(3-methylbut-2-enyl)-1,6-methylenedioxybenzene-3-ol (2), illicinole (3), 3-hydroxy-4,5-methylenedi
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Two new tetrahydrofuran lignans, kadlongirins A and B (1, 2), a new cadinane-type sesquiterpenoid, 2,7-dihydroxy-1 1,1 2-dehydrocalamenene (3), together with seven known lignans, grandisin, fragransin B-1, vladirol F, kadsuralignan C, otobaphenol, isoanwu
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Aim of the study: Previously, we reported that the petroleum ether fraction, RC-1, and EtOAc fraction, RC-2, of the medicinal plant Rhus chinensis showed potent anti-HIV-1 activities. To address anti-HIV-1 constituents of RC-1 and RC-2, 17 compounds were
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Phytochemical investigation of the stems of Kadsura heteroclita led to isolation of 16 compounds, including the triterpenoid named longipcdlactone J (2), and two dibenzocyclooctadiene type lignans named heteroclitin I and J (3, 4). Compounds 8-10, 14, and
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The 70% EtOH extract of Polygonum cuspidatum showed inhibitory action against HIV-1-induced syncytium formation at non-cytotoxic concentrations in vitro with a 50% effective concentration (EC50) of 13.94 +/- 3.41 mu g/mL. Through bioactivity-guided fractionation, 20 phenolic compounds, including eight stilbenoids, were isolated from the roots of Polygonum cuspidatum, and their anti-HIV-1 activities were evaluated. Results showed that compounds 1, 13, 14, and 16 demonstrated fairly strong antiviral activity against HIV-1-induced cytopathic effects in C8166 lymphocytes at non-cytotoxic concentrations, with EC50 values of 4.37 +/- 1.96 mu g/mL, 19.97 +/- 5.09, 14.4 +/- 1.34 mu g/mL, and 11.29 +/- 6.26 mu g/mL and therapeutic index (TI) values of 8.12, > 10.02, > 13.89, and > 17.71, respectively. Other compounds showed either weak or no effects. Compound 6 also showed weak inhibition (153.42 +/- 19.25 mu g/mL); however, it possesses very good water solubility and showed almost no cytotoxicity (> 2000 mu g/mL), therefore achieving a fairly good TI (13.04). The activities of the two compounds (3 and 18) from Polygonum multiflorum were also assayed. The relationship between molecular structures and their bioactivities was also discussed.
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Polyfluorinated and perfluorinated compounds (PFCs) are used in numerous commercial products and have been ubiquitously detected in the environment as well as in the blood of humans and wildlife. To assess the combined effects caused by PFCs in mixtures, gene expression profiles were generated using a custom cDNA microarray to detect changes in primary cultured hepatocytes of rare minnows exposed to six individual PFCs (perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluorododecanoic acid, perfluorooctane sulfonate, and 8:2 fluorotelomer alcohol) and four formulations of the PFCs mixtures. Mixtures as well as individual compounds consistently regulated a particular gene set, which suggests that these conserved genes may play a central role in the toxicity mediated by PFCs. Specifically, a number of genes regulated by the mixtures were identified in this study, which were not affected by exposure to any single component. These genes are implicated in multiple biological functions and processes, including fatty acid metabolism and transport, xenobiotic metabolism, immune responses, and oxidative stress. More than 80% of the altered genes in the PFOA- and PFOS-dominant mixture groups were of the same gene set, while the gene expression profiles from single PFOA and PFOS exposures were not as similar. This work contributes to the development of toxicogenomic approaches in combined toxicity assessment and allows for comprehensive insights into the combined action of PFCs mixtures in multiple environmental matrices. (C) 2009 Elsevier B.V. All rights reserved.
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The presence of the odorous compounds, 2-methylisoborneol (MIB) and geosmin, as well as causative microorganisms in brackish intensive cultivation fishponds in Tianjin, China that had a severe earthy-musty odor were evaluated. The results revealed that MIB was the primary odorous compound present in the Tianjin fishponds, with a concentration ranging from 0.53-5302.7 ng.L-1. Furthermore, the concentration of MIB was found to be closely correlated with the gross biomass of actinomycetes in the water, which ranged from 10.67-1528.24 x 10(6) cfu.ml(-1). Therefore, the sequences of the 16 SrRNA and morphological characteristics of the actinomycetes in the brackish fishponds were investigated. The results revealed that the actinomycetes in the brackish fishponds included 9 species of common and dominant actinomycetes belonging to 4 genera. Of these genera, Streptomyces were the dominant species, and Streptomyces, Nocardioides and Micromonospora were the most common species in the fishponds evaluated. Next, the ability of each of the isolated Streptomyces to produce MIB was measured under laboratory culture conditions. Streptomyces Sp2 was found to have a strong ability to produce MIB, which indicates that this strain may be the primary source of the earthy-musty odor reported in brackish intensive cultivation fishponds in Tianjin, China.
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In laboratory studies, the allelopathic effects of 3 (Hydrocharitaceae family) submerged macrophytes (Elodea nuttallii (Planch) St. John, Hydrilla verticillata (L.f.) Royle and Vallisneria spiralis L.) were investigated on two strains of Microcystis aeruginosa. Both aqueous methanol extracts and exudates of three macrophytes inhibited the growth of both strains of Microcystis aeruginosa, After 3-days culture, E nuttallii, H. verticillata and V. spiralis excreted 0.8, 0.3 and 1.0% of total phenolic compounds (TPC), respectively, into the surrounding water. After removing phenolic compounds by polyvinylpolypyrrolidone (PVPP)), the plant exudates showed very weak activity. The inhibitory rates of exudates of E. nuttallii, H. verticillata and V. spiralis, against non-toxic M. aeruginosa were decreased by 35.7, 43.4 and 59.1% respectively. Thus 3 submerged macrophytes released the phenolic compounds into the surrounding water, to inhibit the growth of M. aeruginosa. This information may help us in understanding the mechanism of allelopathy in aquatic ecosystems and to control the algal bloom in eutrophic water bodies.
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In this study, the levels of 25 semi-volatile organic compounds (SVOCs) were measured in samples of water, suspended particulate matter (SPM) and sediment from two urban lakes in Wuhan, China. The total concentrations of 25 SVOCs varied from 529.4 to 2168.9 ng/L, 120.7 to 22543.7 ng/g dry weight and 1577.3 to 61579.6 ng/g dry wt. in water, SPM and sediment, respectively. The concentration of SVOCs in SPM was 9-10 times higher than that in water, and the concentration of SVOCs in sediment 1.5-2 times higher than that in SPM. The level of total SVOC25 in the samples from Moshuihu Lake was higher than that in Yuehu Lake. Among the 25 SVOCs, phthalate compounds were on the highest level in all observed samples ranging between 441.9-1831.2 ng/L, 116.3-17566.8 ng/g, dry wt. and 6432.8-48177.6 ng/g dry wt. in water, SPM and sediment, respectively. Bis(2-ethylhexyl)phthalate, the predominant component of the analyzed pollutants, was in the range from 246.7 to 537.5 ng/l, 51.2 to 15540.0 ng/g dry wt. and 468.2 to 45010.3 ng/g dry wt. in water, SPM and sediment, respectively. The content of PAHs, dinitrotoluene and isophoton in sediment was higher than that in water and SPM at most of the locations. The possible sources of the pollutants and their inter-relation with human activities were discussed.
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The seasonal variations of estrogenic compounds and the estrogenicities of influent and effluent were investigated by OF chemical analysis and in vitro assay in a municipal sewage treatment plant in Wuhan (China). The levels of eight estrogenic compounds, including 17 beta-estradiol (E-2) estrone (E-1), estriol (E-3) diethylstilbestrol (DES), 17 alpha-ethinylestradiol, nonylphenol (NP), 4-tert-octylphenol (OP), and bisphenol A (BPA), were measured by gas chromatography-mass spectrometry. Total estrogenic activity of sewage was quantitatively assessed using primary cultured hepatocytes of male Megalobrama amblycephala Yih using vitellogenin as a biomarker. The E-2 equivalents (EEQs) obtained from the chemical analysis were consistent with those measured by bioassay. The natural (E-1, E-2, and E-3) and synthetic (DES) estrogens, as well as NP, were the main contributors of the total EEQs of influent and effluent in the present study. The levels of natural estrogens E-1 and E-3 in the influent and effluent were higher in winter than in summer, whereas the situation for NP and OP was the reverse. The levels of E-2, DES, and BPA varied little among different seasons. 17 alpha-Ethinylestradiol was not detected in the influent and effluent. The estrogenicities of the influent and of the primary and secondary effluents were all higher in summer than in winter. Estrogenic activities in winter mainly originated from natural (E-1, E-2, and E-3) and synthetic (DES) estrogens, whereas the increase of EEQs in summer was contributed by NP The results from chemical analysis and bioassay demonstrate that estrogenic compounds cannot be entirely removed by the existing sewage treatment process, which should be further improved to protect aquatic ecosystems and human health.
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A total of 14 perfluorinated compounds (PFCs) were quantified in river water samples collected from tributaries of the Pearl River (Guangzhou Province, south China) and the Yangtze River (central China). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the two compounds with the highest concentrations. PFOS concentrations ranged from 0.90 to 99 ng/1 and < 0.01-14 ng/1 in samples from the Pearl River and Yangtze River, respectively; whereas those for PFOA ranged from 0.85 to 13 ng/l and 2.0-260 ng/l. Lower concentrations were measured for perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctanesulfoamide (PFOSA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorononaoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA). Concentrations of several perfluorocarboxylic acids, including perfluorododecanoic acid (PFDoDA), perfluorotetradecanoic acid (PFTeDA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctadecanoic acid (PFOcDA) were lower than the limits of quantification in all the samples analyzed. The highest concentrations of most PFCs were observed in water samples from the Yangtze River near Shanghai, the major industrial and financial centre in China. In addition, sampling locations in the lower reaches of the Yangtze River with a reduced flow rate might serve as a final sink for contaminants from the upstream river runoffs. Generally, PFOS was the dominant PFC found in samples from the Pearl River, while PFOA was the predominant PFC in water from the Yangtze River. Specifically, a considerable amount of PFBS (22.9-26.1% of total PFC analyzed) was measured in water collected near Nanjing, which indicates the presence of potential sources of PFBS in this part of China. Completely different PFC composition profiles were observed for samples from the Pearl River and the Yangtze River. This indicates the presence of dissimilar sources in these two regions. (c) 2007 Elsevier Ltd. All rights reserved.