Search results for "Fatty alcohol"
showing 10 items of 23 documents
Unravelling the biosynthesis of pyriculol in the rice blast fungus Magnaporthe oryzae
2017
Pyriculol was isolated from the rice blast fungus Magnaporthe oryzae and found to induce lesion formation on rice leaves. These findings suggest that it could be involved in virulence. The gene MoPKS19 was identified to encode a polyketide synthase essential for the production of the polyketide pyriculol in the rice blast fungus M. oryzae. The transcript abundance of MoPKS19 correlates with the biosynthesis rate of pyriculol in a time-dependent manner. Furthermore, gene inactivation of MoPKS19 resulted in a mutant unable to produce pyriculol, pyriculariol and their dihydro derivatives. Inactivation of a putative oxidase-encoding gene MoC19OXR1, which was found to be located in the genome cl…
Acetogenins from Annonaceae: Recent Progress in Isolation, Synthesis and Mechanisms of Action
2005
Covering: the literature from 1998 to 2004 The aim of the present review is to summarise the knowledge about newly isolated acetogenins (ACGs) in the last six years. It will also report the total syntheses that have allowed either the confirmation or the revision of some structures, together with the biological activities and mechanism of action of such interesting natural products. In fact, of the 417 isolated compounds reviewed, over 176 have been added during the period from 1998 to 2004.
Inhibitory effects on mitochondrial complex I of semisynthetic mono-Tetrahydrofuran acetogenin derivatives
2003
Modifications in the terminal alpha,beta-unsaturated gamma-methyl-gamma-lactone moiety or in the alkyl chain that links this terminal gamma-lactone with the alpha,alpha'-dihydroxylated THF system of the natural mono-tetrahydrofuranic acetogenins, annonacin and annonacinone, led to the preparation of eight semisynthetic derivatives. Their inhibitory effects on mitochondrial complex I is discussed and compared with that of the classical complex I inhibitor, rotenone.
Analytical methods for the characterization and determination of nonionic surfactants in cosmetics and environmental matrices
2013
Nonionic synthetic surfactants, constituted of an assortment of classes, are common ingredients of industrial, household and body-care products. Alone or in combination with anionic surfactants, they perform a variety of functions including cleaning action, emulsification, skin conditioning, appearance and consistency modification, solubilization and dispersing agents. By far fatty alcohol ethoxylates (AEs) and alkylphenol ethoxylates (APEs) are more extensively used than any other nonionic surfactant class; however, works appearing in the literature making reference to the analysis of other nonionic surfactant classes have also been collected in this review. The production volume worldwide…
X-ray analysis on the nanogram to microgram scale using porous complexes
2012
X-ray single-crystal diffraction (SCD) analysis has the intrinsic limitation that the target molecules must be obtained as single crystals. Here we report a protocol for SCD analysis that does not require the crystallization of the sample. In our method, tiny crystals of porous complexes are soaked in a solution of the target, such that the complexes can absorb the target molecules. Crystallographic analysis clearly determines the absorbed guest structures along with the host frameworks. Because the SCD analysis is carried out on only one tiny crystal of the complex, the required sample mass is of the nanogram–microgram order. We demonstrate that as little as about 80 nanograms of a sample …
Determination of fatty alcohol ethoxylates and alkylether sulfates by anionic exchange separation, derivatization with a cyclic anhydride and liquid …
2011
A method for the separation, characterization and determination of fatty alcohol ethoxylates (FAE) and alkylether sulfates (AES) in industrial and environmental samples is described. Separation of the two surfactant classes was achieved in a 50:50 methanol-water medium by retaining AES on a strong anionic exchanger (SAX) whereas most FAE were eluted. After washing the SAX cartridges to remove cations, the residual hydrophobic FAE were eluted by increasing methanol to 80%. Finally, AES were eluted using 80:20 and 95:5 methanol-concentrated aqueous HCl mixtures. Methanol and water were removed from the FAE and AES fractions, and the residues were dissolved in 1,4-dioxane. In this medium, este…
Determination of non-ionic and anionic surfactants in industrial products by separation on a weak ion-exchanger, derivatization and liquid chromatogr…
2013
Abstract A method for the determination of priority surfactants, including fatty alcohol ethoxylates (FAE), alkylether sulfates (AES) and linear alkylbenzene sulfonates (LAS) is described. The samples were diluted with 50% methanol at pH 4 prior to solid-phase extraction on a weak anionic exchanger (WAX). The AES and LAS surfactant classes were retained, whereas the non-ionic components, including most FAE oligomers were eluted. After washing the WAX cartridge to remove cations, the remaining hydrophobic FAE oligomers were eluted using hot 80% methanol at pH 4 (at ca. 50 °C). These two eluates were combined to constitute the non-ionic fraction. Then, AES and LAS were eluted using 80% MeOH w…
Long-chain fatty alcohols from pomace olive oil modulate the release of proinflammatory mediators
2009
Pomace olive oil is a by-product of olive oil extraction that is traditionally produced and consumed in Spain. The nonglyceride matter of this oil is a good source of interesting minor compounds, like long-chain fatty alcohols, which are present free or as part of waxes. In the present study, long-chain fatty alcohols were isolated from the nonglyceride fraction of pomace olive oil, and the composition was identified and quantified. The major components of long-chain fatty alcohols were tetracosanol, hexacosanol and octacosanol. We investigated the ability of long-chain fatty alcohols from pomace olive oil to inhibit the release of different proinflammatory mediators in vitro by cells invol…
Spectroscopic study of the aluminium/lumogallion system in the presence of non-ionic surfactants
1987
Abstract The effects of different non-ionic ethylene oxide condensate surfactants on the fluorescence and the molecular absorption of the aluminium/lumogallion system are reported. Ethylene oxide condensates with fatty alcohols give higher micellar enhancement factors than tert-octylphenols or nonylphenols; ethylene oxide/propylene oxide copolymers provide only a 50% increase in the fluorescence of the complex. The aluminium/lumogallion seems to form mixed micelles with the fatty alcohol condensates; the strong complex/micelle interaction provides increased absorbance of the complex at 500 nm and higher fluorescence enhancement, allowing the detection of 0.11 μg l −1 aluminium.
Derivatization of hydroxyl functional groups for liquid chromatography and capillary electroseparation
2013
The derivatization reactions commonly used to enhance the analytical signal in the HPLC and CE determination of compounds with hydroxyl functional groups are revised. Focus is placed on the determination of compounds having aliphatic alcohols and phenols while lacking other reactive functional groups. The derivatization with acyl chlorides, organic anhydrides, isocyanates and a variety of other approaches, including oxidation of primary and secondary alcohols, sulfonation, esterification with carboxylic acids, and the use of azides, sulfonyl chlorides and other reagents having miscellaneous leaving groups, is covered. Reactions mainly addressed to introduce a chromophore or a fluorophore in…