Palmitic Anhydride Research Articles

Enhanced Enzymatic Synthesis of Puerarin Palmitate with Different Acyl Donors for Lipid Solubility Improvement.

Puerarin is a flavonoid known as a natural antioxidant found in the root of Pueraria robata. Its antioxidant, anticancer, and anti-inflammatory effects have attracted attention as a potential functional ingredient in various bioindustries. However, puerarin has limited bioavailability owing to its low lipid solubility and stability. Acylation is proposed as a synthesis method to overcome this limitation. In this study, lipase-catalyzed acylation of puerarin and various acyl donors was performed, and the enzymatic synthetic condition was optimized. Under the condition (20 g/L of Novozym 435, palmitic anhydride, 1:15, 40 °C, tetrahydrofuran (THF)), the synthesis of puerarin ester achieved a significantly high conversion (98.97%) within a short time (3 h). The molecule of the synthesized puerarin palmitate was identified by various analyses such as liquid chromatography-mass spectrometry (LC-MS), Fourier-transform infrared spectroscopy (FT-IR), and carbon-13 nuclear magnetic resonance (13C NMR). The lipid solubility and the radical scavenging activity were also evaluated. Puerarin palmitate showed a slight decrease in antioxidant activity, but lipid solubility was significantly improved, improving bioavailability. The high conversion achieved for puerarin esters in this study will provide the foundation for industrial applications.

Phytochemical screening and Gas chromatography-mass spectrometry analysis on Ischaemumpilosum (Kleinex Willd.)

Ischaemumpilosum (Kleinex Willd.) a weed among the grass is reported for ethno-medicinal practices for treatment of various treatments for human and domestic animals. The current work deals with phytochemical analysis in different parts of plants to find out bioactive compounds. The first-time reported results onI. pilosumreveal the significant phytochemicals by using preliminary phytochemical analysis, UV Visible spectral technique, FTIR analysis and GC-MS analysis. The preliminary phytochemical test confirms the presence of alkaloids, anthraquinone, cardiac glycosides, coumarins, flavonoids, glycosides, phenols, reducing sugars, saponins, steroids, tannin and triterpenes in Ischaemumpilosum.UV Visible spectra and FTIR gives the ranges of absorptions and functional group like Carboxylic acids (O-H) at 2956,92 cm-1, Alkanes (O-H) at 2849,89 cm-1, Aldehydes (C=O) at 1735,92 cm-1, Aromatic Rings (C=C) at 1462,95 cm-1, Alkanes (C-H) at 1377,97 cm-1, Esters (C-O) 1166,95 cm-1and Phenyl Ring (C-H) 758,97 cm-1. The GC-MS analysis related twenty-one compounds like Phenol, 4-bis (1,1-dimethylethyl), Pentanoic acid, 5-hydroxy, 2,4-di-t-butylphenyl esters, E-15-Heptadecenal, 1-Hexadecanol, n-Hexadecanoic acid, l (+)-Ascorbic acid 2,6-dihexadecanoate, Palmitic anhydride, Cycloeicosane, Cis-13-Octadecenoic acid and Triacontane from Ischaemumpilosumleaves extract.

Esterification of Mixed Carboxylic-fatty Anhydrides Using Amberlyst-15 as Heterogeneous Catalyst.

The article deals with the use of mixed anhydrides for the synthesis of fatty esters. Both aliphatic and aromatic acids are involved, indicating different behaviors according to the chain length of the aliphatic acid. We describe a novel and efficient method for the synthesis of fatty esters by the esterification reaction of primary, secondary and tertiary alcohols with mixed carboxylic-palmitic anhydrides using resin Amberlyst-15 as heterogeneous acid catalyst. Influence of various reaction parameters such as molar ratio (anhydride/alcohol), catalyst amount, type of alcohol and type of mixed anhydride were studied to optimize the conditions for maximum yield. Among tested anhydrides we quote mainly the 4-chlorobenzoic palmitic anhydride because it was both reactive and selective for the preparation of palmitic acid ester. This anhydride gave a good yield of palmitic ester.

Assessment of acylation routes and structural characterisation by liquid chromatography/tandem mass spectrometry of semi-synthetic acyl ester analogues of lipophilic marine toxins.

Esterification is one of the most important metabolic routes of lipophilic marine toxins in shellfish. In this work we assessed several chemical acylation reactions aimed at obtaining acyl ester analogues via partial synthesis from the free toxins. The procedures developed including sensitive and selective methods based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) can be applied to obtain reference materials that may be used as analytical standards (internal/external) for method development and calibration, as well as to perform toxicological in vitro and in vivo studies. Acylation systems involved both anhydrous and non-anhydrous fatty acid or acid halides as a source of the acyl radical, and several catalysers of the reaction. A series of mass spectrometric experiments involving product ion scans and multiple reaction monitoring (MRM) were used to confirm the identity and to elucidate the fragmentation pathways of the synthesised products. Reaction yields regarding reaction time and temperature were examined at sub-nmol scale for the acylation system consisting of palmitic anhydride and 4-(dimethylamino)pyridine (DMAP) in anhydrous pyridine, showing the best conditions at 75 °C for 60 min, 75 °C for 120 min and 100 °C for 270 min for cyclic imines, azaspiracid-1 and pectenotoxin-2, respectively. The esterification approach was verified at a larger scale for the esterification of gymnodimine-A (GYM-A), which kept a good yield >90% for the synthesis of 10-O-palmitoyl-GYM-A. Acyl ester analogues of lipophilic marine toxins have been synthesised and their structure elucidated by LC/MS/MS. For acyl ester analogues identical to natural metabolites, the procedures developed have potential to be applied for the semi-synthesis of metabolites in a sustainable, scalable and controlled way, avoiding extensive and tedious isolation and purification procedures from naturally contaminated shellfish. For the semi-synthetic esters structurally different than those found in shellfish, they may have applicability as internal standards for accurate quantifications of natural metabolites present in complex matrices.

Modified cellulose microfibrils as benzene adsorbent

Abstract Jute fibres have been used as raw material for cellulose microfibril isolation using two chemical treatments: acid delignification and acetylation to purify the obtained cellulose. Combined with these methods fibres were mechanically treated in order to fibrillate the fibres and microfibrils obtained after each chemical treatment. The isolated microfibrils were treated with palmitic acid in order to obtain a long hydrocarbon chain able to retain organic molecules in water. In this way, palmitic anhydride was firstly obtained from the reaction of palmitic acid and acetic anhydride and used in a second step to esterify cellulose microfibrils promoting the reaction between the carbonyl groups of the obtained anhydride and the hydroxyl groups of cellulosic chains by the addition of 4-(Dimethylamino)pyridine (DMAP) as catalyst. Treated fibres were characterised by Fourier transformed infrared spectroscopy and contact angle measurements. Retention of organic molecules was determined by using ultraviolet spectroscopy.

Biocatalytic synthesis of palmitoyl vanillylamide in supercritical carbon dioxide through amidation of vanillylamine hydrochloride and palmitic anhydride by lipase

Capsaicin (8-methyl- N-vanillyl-6-nonenamide) is the main pungent component in capsicum fruits. Its analog, palmitoyl vanillylamide, with similar properties, was synthesized through amidation by lipase in supercritical carbon dioxide (SC–CO 2) and reaction conditions were optimized. Among five lipases tested, immobilized Mucor miehei lipase, Lipozyme IM, was most effective in synthesizing this analog. The reaction conditions for analog synthesis were optimized and were 50 °C, 17 MPa and pH 8 for 23 h using vanillylamine hydrochloride and palmitic anhydride at a molar ratio of 5/15 as substrates catalyzed by Lipozyem IM at a concentration of 0.5% (w/w). The residual enzyme activity was about 40% and 15% after a 46- and 69-h repeated amidation reaction in a batch reaction under optimized conditions, suggesting further modification of conditions was required.

Discovery of fatty acid ester metabolites of spirolide toxins in mussels from Norway using liquid chromatography/tandem mass spectrometry

Cultured mussels sampled in the spring of 2002 and 2003 from Skjer, a location in the Sognefjord, Norway, tested positive in the mouse bioassay for lipophilic toxins. In a previous report, it was established that a number of spirolides, cyclic imine toxins produced by the phytoplankton Alexandrium ostenfeldii, were present in the mussels and were responsible for the observed toxicity. The main toxin proved to be a new compound named 20-methyl spirolide G. In subsequent studies, a delayed onset of spirolide-like symptoms in the mouse bioassay exceeding the usual time limit of 20 min was observed in some samples, with symptoms and death appearing as long as 45-50 min after injection. It is well known that shellfish can extensively metabolize other toxins, such as okadaic acid and the dinophysistoxins, to fatty acid acyl esters and it is also known that a delayed onset of toxic symptoms with such metabolites can occur. Analyses performed with liquid chromatography/tandem mass spectrometry (LC/MS/MS) have revealed a complex mixture of esters of 20-methyl spirolide G in the contaminated mussels. Precursor ion scanning has delineated the range of fatty acid esters involved, while product ion scanning has provided information on structure. Identity was also supported through reaction of 20-methyl spirolide G with palmitic anhydride, which produced a derivative with a retention time and spectrum identical with one putative metabolite, 17-O-palmitoyl-20-methyl spirolide G.

Novel Polymer Micelles Prepared from Chitosan Grafted Hydrophobic Palmitoyl Groups for Drug Delivery

Chitosan-based polymer micelles have a splendid outlook for drug delivery owing to the interesting properties, abundance, and low cost of chitosan. A new method of preparation of water-soluble N-palmitoyl chitosan (PLCS) which can form micelles in water is developed in this paper. The preparation of PLCS was carried out by swollen chitosan coupling with palmitic anhydride in dimethyl sulfoxide (DMSO). The degree of substitution (DS) of PLCS was in the range of 1.2-14.2%, and the critical aggregation concentration (CAC) of PLCS micelles was in the range of 2.0 x 10(-3) to 37.2 x 10(-3) mg/mL. The properties of PLCS micelles such as encapsulation capacity and controlled release ability of hydrophobic model drug ibuprofen (IBU) were evaluated. Experimental results indicated that the loading capacity (LC) of PLCS was approximately 10%. The drug release strongly depended on pH and temperature: low pH and high temperature accelerated drug release markedly. Moreover, the IR, 1H NMR, and TEM of PLCS, IBU-loaded PLCS, and a PLCS-IBU physical mixture have been measured to show that IBU is loaded by PLCS micelles.

Development of an emulsion prepared with lipophilized gelatin and its application for hormone administration in the Japanese eel Anguilla japonica.

A new water-in-oil-in-water (W/O/W) type emulsion using lipophilized gelatin (LG) and cotton-seed oil was developed for a novel method of hormone administration in fishes. LG was prepared by attaching palmitic anhydride to gelatin. The best conditions for preparing stable emulsions were determined where the final concentrations of LG in the emulsion and the volume ratio of LG solution to cotton-seed oil were 2% and 1:2, respectively. Hormone releasing properties of LG emulsion were compared with a water-in-oil (W/O) type emulsion prepared with Freund's incomplete adjuvant (FIA) and saline solution by monitoring plasma profiles of salmon gonadotropin (sGtH) II in the Japanese eel. sGtH II is gradually released from the LG emulsion. LG emulsion had hormone-releasing properties different from those of the saline solution and the FIA emulsion. Immature female Japanese eel (BW, 566 to 1017 g) received a weekly intramuscular injections (total of 10 injections) of the LG emulsion, the FIA emulsion or the saline solution, each of which contained sGtH fraction. The LG emulsion was found to be more effective in inducing ovarian maturation. In mature eel, final maturation and ovulation could be induced by simultaneous administration of sGtH fraction and 17α-hydroxyprogesterone using LG W/O/W emulsion.

Characterization of a lipophilized gelatin prepared by a new method

A new method for the preparation of lipophilized gelatin (LG) was developed. Gelatin dissolved using a microwave oven was easily lipophilized via reaction with fatty acid anhydrides for 3 hr at 50 °C and the subsequent emulsion was prepared by mixing LG and cotton seed oil. Palmitic anhydride LG was the most useful material for preparing stable emulsions. The emulsion was a multiple water-in-oil-in-water type.

A novel method of hormone administration for inducing gonadal maturation in fish

A new water-in-oil-in-water (W/O/W) type emulsion using lipophilized gelatin (LG) with palmitic anhydride and cotton-seed oil was developed for a novel method of hormone administration in fish. In the in vitro release experiments, the concentration of LG in the emulsion was determined to be 2% and the volume ratio of LG solution to cotton-seed oil adequate for obtaining the best-formed emulsion was 1:2. Plasma profiles of salmon GtH II were monitored in the Japanese eel during in vivo release experiment. Groups administered LG emulsion containing either pituitary saline extract or glycoprotein fraction of salmon pituitary had plasma salmon GtH II levels that increased slowly, peaked after 24 h (about 2–2.5 μg ml −1) and then gradually decreased. In the group administered only salmon pituitary saline extract, the levels rapidly attained a very high peak (about 20 μg ml −1) after 3 h and then acutely decreased. These results clearly indicate that GtH is gradually released from the LG emulsion.

Synthesis and in vitro Antiviral Properties of Amphiphilic Dinucleoside Phosphate Derivatives of 2′,3-dideoxycytidine (ddC)

N4-hexadecyl-5′-0-(4-monomethoxytrityl)-2′-deoxycytidine-3′-hydrogenphosphonate and 5′-0-(4-monomethoxytrityl)-2′-deoxythymidine-3′-0-hydrogenphosphonate were condensed with 2′,3′-dideoxycytidine (ddC) according to the hydrogenphosphonate method to yield N4-hexadecyl-2′-deoxycytidylyl-(3′-5′)-2′,3′-dideoxycytidine (N4-hexadecyldC-ddC) and 2′-deoxythymidylyl-(3′-5′)-N4-palmitoyl-2′,3′-dideoxycytidine (dT-N4-palmddC). N4-palmitoyl-2′,3′-dideoxycytidine (N4-palmddC) was synthesized by reacting palmitic anhydride with ddC. Both dinucleoside phosphates have amphiphilic properties and represent a new class of ddC derivatives in which in the case of the dinucleosides, the ddC-5′-monophosphate is masked with lipophilic residues of variable stability. The ddC derivatives can be solubilized in water by micelle formation and, because they have lipophilic residues, they can be incorporated into the lipid membranes of liposomes. The ddC derivatives were shown to have antiviral activities comparable to those of AZT and ddC when tested in vitro against HIV-1-infected HeLa and H9 cells as well as infected human monocytes/macrophages.

Lipase-catalyzed enantioselective esterification or hydrolysis of 1-O-alkyl-3-O-tosylglycerol derivatives. Practical synthesis of (S)-(+)-1-O-hexadecyl-2,3-di-O-hexadecanoylglycerol, a marine natural product

Racemic 1-O-alkyl-3-O-tosylglycerol derivatives were resolved by acylation with palmitic anhydride in the presence of Pseudomonas fluorescens lipase in organic media. The reverse reaction, the ezymatic hydrolysis of 1-O-alkyl-2-O-palmitoyl-3-O-tosylglycerols in isopropyl ether saturated with water was also highly stereoselective. An efficient and simple synthesis of the naturally occuring (S)-(+)-1-O-hexadecyl-2,3-di-O-hexadecanoyglycerol based on this process is reported

Synthesis of a 4-Deoxy-4-C-Methylene Analog of Glucosylceramide

Abstract D-Glucose was transformed into 2,3:5,6-di-O-isopropylidene dithioacetal 1; its oxidation to ketone 2 and subsequent Wittig reaction afforded 4-deoxy-4-C-methylene derivative 3. Hydrolytic removal of the protective groups, then O-acetylation, selective anomeric O-deacetylation, and base catalyzed trichloroacetonitrile addition furnished 4-deoxy-4-C-methylene substituted glycopyranosyl donor 7 as an anomeric mixture. Reaction of 7 with azidosphingosine derivative 8 under BF3-OEt2 catalysis gave β-glycopy-ranoside 9. Azido group reduction with triphenylphospnine in the presence of palmitic anhydride and water afforded directly O-acyl protected glycosphingolipid derivative 10 which yielded after Zemplen O-deacylation target molecule 11

DECOMPOSITION OF ALKYLARSONIC ACIDS BY ACYLATING AGENTS

Abstract Benzylarsonic acid is decomposed by palmitoyl chloride. slowly in the absence and rapidly in the presence of pyridine, giving benzyl chloride. Benzylarsonic acid is decomposed by palmitic anhydride in the presence, but not in the absence, of pyridine giving benzyl palmitate and benzyl pyridinium cation.

ChemInform Abstract: Solid‐Phase Phosphatidylethanolamine Synthesis.

Abstract Dipalmitoylphosphatidylethanolamine(DPPE) was prepared from natural phosphatidylethanolamine (cephalin) and palmitic anhydride (PAh) by using polymer-supported trityl as a protective group for the ammo group of cephalin.

Biologically active ether lipids: Biotransformation of rac-1 (3)- O-alkylglycerols in cell suspension cultures of rape and semisynthesis of 1- O-alkyl-2-palmitoyl- sn-glycero-3-phospho-( N-palmitoyl)ethanolamines, potent antitumor agents

Biotransformation of rac-1(3)- O-hexadecylglycerol by photomixotrophic rape ( Brassica napus) cells in suspension culture leads to 1- O-hexadecyl-2-acyl- sn-glycero-3-phosphocholines and small proportions of other ether lipids, e.g. 1- O-hexadecyl-2-acyl- sn-glycero-3-phosphoethanolamines. Reaction of the hexadecylacyl-glycerophosphocholines with ethanolamine in the presence of phospholipase D from Streptomyces chromofuscus yields additional hexadecylacylglycerophosphoethanolamines. Partial hydrolysis of the combined hexadecylacylglycerophosphoethanolamines followed by reacylation of the resulting lyso compound with palmitic anhydride gives 1- O-hexadecyl-2-palmitoyl- sn-glycero-3-phospho-( N-palmitoyl) ethanolamine, a nontoxic ether glycerophospholipid with antitumor activity. The corresponding 1- O-tetradecyl,1- O-octadecyl, and 1- O-[( Z)-9'-octadecenyl] derivatives are prepared similarly.

Solid-Phase Phosphatidylethanolamine Synthesis

Abstract Dipalmitoylphosphatidylethanolamine(DPPE) was prepared from natural phosphatidylethanolamine (cephalin) and palmitic anhydride (PAh) by using polymer-supported trityl as a protective group for the ammo group of cephalin.

Determination of carboxylesterase in rat tissues and blood using riboflavin-5'-monobutyrate.

Riboflavin-5'-monobutyrate (R-MB, mp 244-245°) was synthesized from riboflavin and butyric anhydride (yield : 10%) as well as from riboflavin-2', 3', 4', 5'-tetrabutyrate and hydrazine hydrate (yield : 44%). Riboflavin-5'-monopalmitate (R-MP, mp 228-230°) was also prepared from riboflavin and palmitic anhydride (yield : 9.8%). The absorption, fluorescence, and infrared spectra, and Rf values of R-MB and R-MP are given. R-MP was hardly hydrolyzed by pure hog hepatic carboxylesterase. However, R-MB was readily hydrolyzed to riboflavin by pure hog hepatic carboxylesterase, though not by pure pancreatic lipase (triacylglycerol lipase), acetylcholinesterase, or cholinesterase. The activity of carboxylesterase could therefore be estimated by fluorometric determination of riboflavin hydrolyzed from R-MB. The optimum incubation conditions for the assay of carboxylesterase with R-MB were pH 7, 37°, 15 min. Studies on the rat organs and liver subcellular distributions of carboxylesterase showed that the enzyme is localized in the small intestine, kidneys, lungs, heart, and blood, and high carboxylesterase activity was demonstrated in the microsomal fraction in rat liver. R-MB was a rather specific substrate for carboxylesterase, permitting selective assay of this enzyme activity.