112-80-1Relevant articles and documents
Isoflavone glycosides from aerial parts of Artemisia absinthium
Ahamad,Naquvi,Ali,Mir
, p. 996 - 1000 (2014)
Two new isoflavone glycosides, designated as artemisia bis-isoflavonyl dirhamnoside and artemisia isoflavonyl glucosyl diester, have been isolated from the aerial parts of A. absinthium and their structures established as 7a,7b-bis-[(5a-hydroxy-3′a,4′a-dimethoxyisoflavonyl) (5b,4′b-dihydroxy-3′b-methoxyisoflavonyl)]-4′b-α- Drhamnopyranosyl-(4 → 1)-α-D-rhamnopyranoside and 7,4′-dihydroxyisoflavonyl-7-β-D-glucopyranosyl-(2 → 1)-β-D-glucopyranosyl-(2 → 1)-β-D-glucopyranosyl-(2 → 1)-β-D-glucopyranosyl-6d-(octadec-9′″-enoate)-2d-7″, 11″,15″-trimethylpentadecan-3″,15″-dioic acid-1″-oate on the basis of chemical reactions and spectral data analysis.
Chloroacetoxylation of oleic acid - a kinetic study
Doulia, Danae,Rigas, Fotis,Gimouhopoulos, Kostantinos
, p. 239 - 242 (2000)
The kinetics of the addition reaction of chloroacetic acid to oleic acid (chloroacetoxylation) in the presence of sulfuric acid as a catalyst were investigated. The reactions were carried out at the same concentration of both reactants at various temperatures and catalyst content. The reaction time ranged from 30 min up to 12 h, and the reaction course was observed by determining mainly iodine value, and chlorine content of the oil samples at 30-min intervals. The experimental data fitted the reversible second-first order rate equation for bi-molecular-unimolecular type reactions. The reaction constants of the forward and reverse reactions were obtained at temperatures 70 and 80 °C. The effect of sulfuric acid content on the reaction constant was investigated at 70 and 80 °C.
Hydrothermal deoxygenation of triglycerides over Pd/C aided by in situ hydrogen production from glycerol reforming
Hollak, Stefan A. W.,Ari?ns, Maxim A.,De Jong, Krijn P.,Van Es, Daan S.
, p. 1057 - 1062 (2014)
A one-pot catalytic hydrolysis-deoxygenation reaction for the conversion of unsaturated triglycerides and free fatty acids to linear paraffins and olefins is reported. The hydrothermal deoxygenation reactions are performed in hot compressed water at 250 °C over a Pd/C catalyst in the absence of external H2. We show that aqueous-phase reforming (APR) of glycerol and subsequent water-gas-shift reaction result in the in situ formation of H 2. While this has a significant positive effect on the deoxygenation activity, the product selectivity towards high-value, long-chain olefins remains high. With a little H2elp from my friends: A one-pot hydrolysis-deoxygenation reaction for triglycerides and free fatty acids, which is of particular interest for the production of biofuels and value-added chemicals from nonedible or waste fats and oils, is reported. The reaction is performed over palladium on carbon (Pd/C) at 250 °C without additional H2. Instead, in situ H2 production occurs through glycerol reforming and subsequent water-gas-shift reaction with a positive effect on the deoxygenation activity.
Kinetics and pathways for an algal phospholipid (1,2-dioleoyl-sn-glycero-3- phosphocholine) in high-temperature (175-350 °c) water
Changi, Shujauddin,Savage, Phillip E.,Matzger, Adam J.
, p. 2856 - 2867,12 (2012)
We examined the behavior of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in high-temperature water at 175, 200, 225, and 350 °C. DOPC hydrolyzed to give oleic acid and a number of phosphorus-containing products. The hydrolysis was catalyzed by oleic and phosphoric acids, which were also reaction products. DOPC formed 1-acyl and 2-acyl lyso-phosphatidylcholine (LPC) along with oleic acid as primary products. LPC subsequently formed other phosphorus-containing intermediates, which finally led to phosphoric acid as the ultimate P-containing product. At 350 °C, phosphoric acid and oleic acid were the only products observed. We observed an ester of oleic acid and glycerol (9-octadecenoic-2,3- dihydroxypropyl ester), which likely formed via the hydrolysis of LPC. A reaction network is proposed to explain the formation of the observed products. A quantitative kinetics model based on the proposed pathways was consistent with the experimental data.
Lipase mimetic cyclodextrins
Lee, Youngjun,Devaraj, Neal K.
, p. 1090 - 1094 (2021)
Glycerophospholipids (GPLs) perform numerous essential functions in biology, including forming key structural components of cellular membranes and acting as secondary messengers in signaling pathways. Developing biomimetic molecular devices that can detect specific GPLs would enable modulation of GPL-related processes. However, the compositional diversity of GPLs, combined with their hydrophobic nature, has made it challenging to develop synthetic scaffolds that can react with specific lipid species. By taking advantage of the host-guest chemistry of cyclodextrins, we have engineered a molecular device that can selectively hydrolyze GPLs under physiologically relevant conditions. A chemically modified α-cyclodextrin bearing amine functional groups was shown to hydrolyze lyso-GPLs, generating free fatty acids. Lyso-GPLs are preferentially hydrolyzed when part of a mixture of GPL lipid species, and reaction efficiency was dependent on lyso-GPL chemical structure. These findings lay the groundwork for the development of molecular devices capable of specifically manipulating lipid-related processes in living systems.
Radical nitrile transfer with methanesulfonyl cyanide or P-toluenesulfonyl cyanide to carbon radicals generated from the acyl derivatives of N-hydroxy-2-thiopyridone
Barton,Jaszberenyi,Theodorakis
, p. 3321 - 3324 (1991)
Reaction of methanesulfonyl cyanide or p-toluenesulfonyl cyanide with carbon radicals generated from the acyl derivatives of N-hydroxy-2-thiopyridone gives the corresponding nitriles in high yield. A mechanistic scheme is suggested.
Phospholipases a1 from armillaria ostoyae provide insight into the substrate recognition of a/b-hydrolase fold enzymes
Dippe, Martin,Mueller, Mathias Q.,Sinz, Andrea,Ulbrich-Hofmann, Renate
, p. 1435 - 1448 (2012)
Four enzymes with phospholipase A1(PLA1) activity were purified from the fruiting bodies of the basidiomycete Armillaria ostoyae. The enzymes (PLA1-1, -2, -3 and -4) showed similar isoelectric points (4.3, 3.9, 4.0 and 4.0) and apparent molecular masses in the range of 35-47 kDa. Mass spectrometric analyses of proteolytic fragments revealed sequences homologous to a/b-hydrolase fold enzymes. The enzymes share one conserved region with fungal phospholipases B and the active site sequence with bacterial esterases and PLA1s. PLA1-1 cleaves phospholipids and lysophospholipids with an optimum activity at pH 5.3. In contrast, PLA1-2, -3 and -4 are characterized by broad pH optima in the slightly acidic to neutral range and are additionally capable of hydrolyzing mono- and diglycerides as well as fatty acid methyl esters. All enzymes favor glycerol-based lipids with a single medium-sized fatty acid moiety in the sn-1 position but show reduced activity towards the corresponding 1, 2-diacyl derivatives with bulky long-chain or inflexible saturated fatty acid moieties in the sn-2 position. The enzymes prefer zwitterionic phospholipid substrates and are unable to hydrolyze triglycerides. From the selectivity of these broad-spectrum a/b-hydrolase fold enzymes towards the different classes of their substrates a regiospecific steric hindrance and a head group recognition are concluded.
Synthesis and properties of ascorbyl esters catalyzed by lipozyme TL im using triglycerides as acyl donors
Reyes-Duarte,Lopez-Cortes,Torres,Comelles,Parra,Pena,Ugidos,Ballesteros,Plou
, p. 57 - 64 (2011)
Esters of l-ascorbic acid with long-chain fatty acids (E-304) are employed as antioxidants in foods rich in lipids. Although their enzymatic synthesis offers some advantages compared with the current chemical processes, most of the reported methods employ the immobilized lipase from Candida antarctica as biocatalyst and free fatty acids or activated esters as acyl donors. In order to diminish the cost of the process, we have investigated the synthesis of ascorbyl oleate and ascorbyl palmitate esters with the immobilized Thermomyces lanuginosus lipase Lipozyme TL IM-which is significantly less expensive than Novozym 435-and triglycerides as source of fatty acids. Lipozyme TL IM gave rise to a lower yield of 6-O-ascorbyl oleate than Novozym 435 when using triolein (64 vs. 84%) and olive oil (27 vs. 33%) as acyl donors. Both 6-O-ascorbyl oleate and 6-O-ascorbyl palmitate displayed excellent surfactant and antioxidant properties. The Trolox Equivalent Antioxidant Capability values for the oleate and palmitate were 71 and 84%, respectively, of those obtained with l-ascorbic acid; however, both derivatives were able to stabilize soybean oil towards peroxide formation.
Purification and biochemical characterization of an extracellular lipase from Pseudomonas fluorescens MTCC 2421
Chakraborty, Kajal,Paulraj
, p. 3859 - 3866 (2009)
An extracellular lipase produced by Pseudomonas fluorescens MTCC 2421 was purified 184.37-fold with a specific activity of 424.04 LU/mg after anion exchange and gel exclusion chromatography. The enzyme is a homomeric protein with an apparent molecular mass of 65.3 kDa. The lipase exhibited hydrolytic resistance toward triglycerides with longer fatty acyl chain length containing unsaturation as evident from the lower Vmax (0.23 mM/mg/min) of the lipase toward glycerol trioleate (C18:1n9) compared with the fatty acid triglycerides having short to medium carbon chain lengths (C 18:0-12:0, Vmax 0.32-0.51 mM/mg/min). This indicates a preferential specificity of the lipase toward cleaving shorter carbon chain length fatty acid triglycerides. The lipase exhibited optimum activity at 40 °C and pH 8.0, respectively. A combination of Ca2+ and sorbitol induced a synergistic effect on the thermostability of lipase with a significantly high residual activity (100%) after 30 min at 40 °C, as compared to 90.6% after incubation with Ca2+ alone. The lipase activity was inhibited by Cu2+ and Fe2+ (42 and 48%,respectively) at 10 mM. The enzyme lost 31% of its initial activity by 0.001 mM EDTA and 42% by 0.1 mM EDTA. Significant reduction in lipase activity was apparent by 2-mercaptoethanol and phenylmethanesulfonyl fluoride at diluted concentration (0.001 mM), thereby indicating an important role of sulfhydryl groups in the catalytic mechanism.
Fatty acid eutectic mixtures and derivatives from non-edible animal fat as phase change materials
Gallart-Sirvent, Pau,Martín, Marc,Villorbina, Gemma,Balcells, Mercè,Solé, Aran,Barrenche, Camila,Cabeza, Luisa F.,Canela-Garayoa, Ramon
, p. 24133 - 24139 (2017)
A set of compounds from non-edible fat waste was prepared and their thermal behavior was studied. The fat was hydrolyzed and crystallized in a simple and robust process to yield palmitic acid-stearic acid (PA-SA) mixtures. The PA-SA mass ratios determined by GC-FID (gas chromatography-flame ionization detection) were similar to those reported for eutectic mixtures of PCMs (phase change materials). DSC (differential scanning calorimetry) results indicated that the melting and solidification temperatures were around 55 °C and 52 °C and the latent heat of the crystallized fractions measured was around 180 kJ kg-1. The thermal cycling reliability of the eutectic mixtures was also tested during 1000 melting/freezing cycles. The loss in melting and solidification enthalpies was below 14% in all mixtures showing a promising behavior for PCM applications. Additionally, the unsaturated fatty acids were recovered and transformed to threo-9,10-dihydroxystearic acid (DHSA) and some of their inorganic salts, which were analyzed by FT-IR (Fourier transform-infrared spectroscopy) and tested for the first time using the DSC technique.
