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Oxidized Compounds (oxidized + compound)
Selected AbstractsAnalysis of Headspace Volatile and Oxidized Volatile Compounds in DHA-enriched Fish Oil on Accelerated Oxidative StorageJOURNAL OF FOOD SCIENCE, Issue 7 2003H. Lee ABSTRACT: Oxidative stability of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and volatile and oxidized volatile compounds in 2 types of DHA-enriched fish oil, triacylglycerol (TG) and ethyl ester (EE), were studied during storage at 80 °C with aeration. The rate of DHA autoxidation was higher than that of EPA. DHA in EE form was more susceptible to autoxidation than in TG form. Thirty-one volatile compounds were identified in EE and 23 volatile compounds in TG. (E)-2-pentenal, 2-(1-pentenyl) furan, and (E,E)-2,4-heptadienal were commonly detected as oxidized volatile compounds from TG and EE fish oil. These volatile oxidized compounds might be formed mainly from the oxidation of DHA and EPA, the main fatty acids of the oil. [source] Synthesis of models of metabolites: Oxidation of variously substituted chromenes including acronycine, by a porphyrin catalytic systemJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 7 2005Bernardin Akagah The influence of chemical neighbouring on oxidation of substituted 2,2-dimethylchromenes derivatives 5-8 by a biomimetic catalytic system was first studied. It was then applied to acronycine an anti-cancer drug in order to obtain in one single step oxidized products resulting from the reactivity of the 1,2-double bond in the pyranic D-ring. These 2,2-dimethylchromenes constitute the structural moiety responsible for the activity of acronycine. This oxidation showed the sensitivity of the ethylenic bond, leading to the formation of the corresponding epoxides, diols and/or ketoalcohol. In the case of 5-dimethylamino-2,2-dimethylchromene 8, the double bond was not sensitive to oxidation, but the N -methyl groups reacted to lead to the formamide derivative 16 and an imino-alcohol 17. This methodology applied to acronycine molecule 1, allowed to obtain in one step, two oxidized compounds, a trans -diol 3 and a ketoalcohol 4 under preparative conditions. [source] Indole and 7-hydroxyindole diminish Pseudomonas aeruginosa virulenceMICROBIAL BIOTECHNOLOGY, Issue 1 2009Jintae Lee Summary Indole is an extracellular biofilm signal for Escherichia coli, and many bacterial oxygenases readily convert indole to various oxidized compounds including 7-hydroxyindole (7HI). Here we investigate the impact of indole and 7HI on Pseudomonas aeruginosa PAO1 virulence and quorum sensing (QS)-regulated phenotypes; this strain does not synthesize these compounds but degrades them rapidly. Indole and 7HI both altered extensively gene expression in a manner opposite that of acylhomoserine lactones; the most repressed genes encode the mexGHI-opmD multidrug efflux pump and genes involved in the synthesis of QS-regulated virulence factors including pyocyanin (phz operon), 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS) signal (pqs operon), pyochelin (pch operon) and pyoverdine (pvd operon). Corroborating these microarray results, indole and 7HI decreased production of pyocyanin, rhamnolipid, PQS and pyoverdine and enhanced antibiotic resistance. In addition, indole affected the utilization of carbon, nitrogen and phosphorus, and 7HI abolished swarming motility. Furthermore, 7HI reduced pulmonary colonization of P. aeruginosa in guinea pigs and increased clearance in lungs. Hence, indole-related compounds have potential as a novel antivirulence approach for the recalcitrant pathogen P. aeruginosa. [source] Neutral and Oxidized Triisopropylsilyl End-Capped Oligothienoacenes: A Combined Electrochemical, Spectroscopic, and Theoretical StudyCHEMISTRY - A EUROPEAN JOURNAL, Issue 18 2010Juan Aragó Abstract This work presents an analysis of the structural, electrochemical, and optical properties of a family of triisopropylsilyl end-capped oligothienoacenes (TIPS- Tn -TIPS, n=4,8) by combining cyclic voltammetry, spectroscopic techniques, and quantum-chemical calculations. TIPS- Tn -TIPS compounds form stable radical cations, and dications are only obtained for the longest oligomers (n=7 and 8). Oxidation leads to the quinoidization of the conjugated backbone, from which electrons are mainly extracted. The absorption and fluorescence spectra show partially resolved vibronic structures even at room temperature, due to the rigid molecular geometry. Two well-resolved vibronic progressions are observed at low temperatures due to the vibronic coupling, with normal modes showing wavenumbers of ,1525 and ,480,cm,1. Optical absorption bands display remarkable bathochromic dispersion with the oligomer length, indicative of the extent of , conjugation. The optical properties of the oxidized compounds are characterized by in situ UV/Vis/NIR spectroelectrochemistry. The radical cation species show two intense absorption bands emerging at energies lower than in the neutral compounds. The formation of the dication is only detected for the heptamer and the octamer, and shows a new band at intermediate energies. Optical data are interpreted with the help of density functional theory calculations performed at the B3LYP/6-31G** level, both for the neutral and the oxidized compounds. [source] | ||||||||||