995 resultados para Optimum chemical balance


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Essential oil was extracted from leaves of Hyptis pectinata using hydrodistillation, and its composition determined using GC-FID and GC-MS. Chemical analysis showed that there was a predominance of sesquiterpenes, of which β-caryophyllene (18.34%), caryophyllene oxide (18.00%) and calamusenone (24.68%) were measured for the first time in the genus Hyptis. Twenty-one compounds were identified, and calamusenone was isolated using preparative thin layer chromatography with a silica gel plate (60 PF254). The minimal inhibitory concentration (MIC) and minimal microbicidal concentration (MMC) were determined for various pathogenic microorganisms. H. pectinata oil was most effective against Gram (+) bacteria and yeasts.

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This paper describes the isolation of five phytoconstituents from Marlierea tomentosa. The triterpenes α-amyrin (1) and β-amyrin (2), and the flavonoids quercitrin (3) and isoquercetin (4), were isolated from the leaves. The branches afforded the triterpene arjunolic acid (5). The antinociceptive activity of crude extract, fractions and compound 5 were tested using the writhing and formalin tests in mice. The crude extract, some fractions, particularly dichloromethane and butanol (leaves), ethyl acetate (branches) and arjunolic acid (5) (81.2% inhibition) were more active against the writhing test than the two reference drugs, acetylsalicylic acid and indomethacin.

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The phytochemical investigation of the wood extracts of Senna reticulata (Leguminoseae) yielded six anthraquinones: chrysophanol, physcion, aloe-emodin, 1,3,8-trihydroxyanthraquinone, 3-methoxy-1,6,8-trihydroxyanthraquinone, emodin and the chrysophanol-10,10' bianthrone. The triterpenes a and b-amirin, the steroids b-sitosterol and stigmasterol as well as the flavonoid kaempferol were also identified. The structures were established by spectral analysis, including two-dimensional NMR techniques. It is the first report of 1,3,8-trihydroxyanthraquinone and 3-methoxy-1,6,8-trihydroxyanthraquinone in higher plants.

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This paper discusses of the use of the Impact Factor in the evaluation of chemistry graduate courses by CAPES and the internationalization of the Journal of the Brazilian Chemical Society and Química Nova.

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relationship between productivity and international position of Spanish chemical firms in the period 2005-2011. The goal is to determine whether companies that follow and international strategy, either with exports or by investment in foreign countries obtain greater productivity growth than these that do not operate in global market. For this purpose a panel data set with microdata has been created. A preliminary analysis of the evolution of productivity growth in the sector is carried out. The measurement of Total Factor Productivity is performed. With the estimated TFP we analyze the differentials in productivity growth, comparing the effects of export and investment behavior with non-international firms.