Palmitic Ester Research Articles

Long-term effects of teflutixol on the synthesis and endogenous levels of mouse brain catecholamines.

Abstract—The long term effects on accumulation of 14C‐labelled dopamine and noradrenaline after [14C]tyrosine administration and on the endogenous levels of catecholamines in mouse brain were studied after treatment with a new potent thioxanthene neuroleptic, teflutixol. The drug was given as a single dose (5 mg/kg i.p.), as repeated daily doses (1·25 mg/kg p.o.), or as a single dose of the palmitic ester in Viscoleo® (20 mg/kg s.c). After a single dose, teflutixol increased catecholamine synthesis (100%). Noradrenaline synthesis rapidly returned to normal, whereas decreased dopamine synthesis was seen from the third to sixth day, after which it was normal. When the receptors were continuously exposed to teflutixol, either by daily dosage or by the depot preparation, catecholamine synthesis was increased for the first few days but then returned to normal, indicating development of tolerance. Endogenous concentrations of catecholamines were only decreased during the first few days, when the increase in synthesis was greatest. The findings are in accordance with results obtained by Møller Nielsen & Christensen (1975), who found that receptor blockade was followed by receptor supersensitivity after treatment with a neuroleptic compound. The receptor blockade may activate a feedback mechanism that induces increased nervous firing with increased amine synthesis as a consequence. The resulting supersensitivity, if sufficiently great, may lead to reduced nervous firing, followed by slowing of dopamine synthesis.

Inhibition of striatal dopamine synthesis in rats injected chronically with neuroleptics in their early life

3H-dopamine synthesis from L-3,5-3H-tyrosine was reduced in striatal slices of 40 days old rats treated during their early life with neuroleptics. Animals were first injected intra-utero with thioproperazine (5 mg/kg) or with the palmitic ester of pipotiazine (32 mg/kg); the thioproperazine-treated rats were then injected every day from day 1 to day 37; the animals injected with the long acting neuroleptic were injected once more with the drug on day 15 after birth.

Formation of palmitate esters of monohydric short chain alcohols by swine arterial subcellular fractions.

AbstractAlcohols of 1–5 carbon chain length were esterified with palmitic acid and palmitoyl CoA substrates by swine aortic cytosol, mitochondrial, and microsomal fractions. Esterification of the palmitic acid substrate with ethanol was enhanced by the addition of adenosine 5′‐triphosphate and CoA to the mitochondrial and microsomal fractions. The rate of esterification of ethanol was most rapid in the microsomal fraction and with the palmitoyl CoA substrate. Esterification was linearly related to time of incubation, was optimal at pH 6.8, and could be inactivated by heating at 90 C. Esterification was inactivated by ethanol concentrations above 0.8 M and by lower concentrations of the other alcohols. Rates of esterification were highest with n‐propanol and lowest with tert‐butanol and the pentanols. The formation of cholesteryl esters by the aortic microsomes was inhibited by ethanol and was inversely related to the rate of ethyl palmitate formation.

Calorimetric Study of Liquid Crystalline Behavior for some 9,19–Cyclopropane Tetracyclic Triterpene Palmitatest

A calorimetric investigation has been made of the mesomorphic behavior for the palmitate esters for four tetracyclic triterpenes-pollinastanol, 31-norcycloartanol, cyclaoartanol, and cyclorartenol....

Kinetics of hydrolysis of polyoxyethylene (20) sorbitan fatty acid ester surfactants.

Abstract The kinetics of the hydrolysis of the oleate ester of polyoxyethylene (20) sorbitan (Tween 80) in aqueous buffers were studied at an initial concentration of 0ṁ020% (w/v) and over the pH range of 1ṁ10 to 10ṁ28. The hydrolysis appears to be specific acid-catalysed at pH values below 3 and specific base-catalysed at pH values greater than 7ṁ6. The pseudo first-order rate constants for hydrogen and hydroxyl ion catalysis were determined, and the temperature and ionic strength dependence of the acid-catalysed reaction was studied. Both the initial, acid- and base-catalysed hydrolysis of Tween 80 exhibited an unusual initial, micellar surfactant concentration-rate dependence, opposite to that previously reported for the hydrolysis of anionic surfactants of the n-alkyl sulphate-type. Specifically, as the initial concentration of Tween 80 was increased above its reported critical micellar concentration, there was a progressive, marked decrease in the rate of the reaction, with the rate eventually reaching a plateau value between 0ṁ100 and 1ṁ00% (w/v). It is suggested that this behaviour is due to alterations in the micellar state of the surfactant as its concentration is increased. The influence of the chemical structure of the Tween surfactant on the acid-catalysed hydrolysis reaction at 80° was also examined using the oléate (Tween 80), stéarate (Tween 60), and palmitate (Tween 40) esters of polyoxyethylene (20) sorbitan.

Studies on the digestive lipase of the surf clam Spisula solidissima

Crude molluscan lipase was prepared by homogenizing in tris buffer either fresh or lyophilized crystalline styles of Spisula solidissima. Both preparations showed specific activities less than 2% of standard hog pancreatic lipase, and pH and temperature optima of 8.0 and 20°C, respectively. When compared with mammalian hog pancreatic lipase, the clam lipase was found to be the more versatile enzyme on primary wax esters as well as methyl esters. Neither lipase was capable of hydrolyzing the oleate or palmitate esters of the secondary alcohols of glycerol, cholesterol or isopropyl alcohol; however, both showed activity on the oleate ester of isobutyl alcohol, a primary alcohol. S. solidissima lipase, hog pancreatic lipase, and a lipase isolated from the pancreas of the skate Raja erinacea, all demonstrated an inability to hydrolyze the methyl esters of eicosatetraenoic, eicosapentaenoic and docosahexaenoic acids. The lipase-resistant polyunsaturated fatty acid esters are discussed in terms of their role in the lipid biochemistry of marine organisms.

The oral toxicity of clindamycin in laboratory animals

The potoxicities of clindamycin hydrochloride and clindamycin palmitate have been extensively studied in mice, rats and dogs. For the hydrochloride, the ip mouse and po rat LD50 values were 361 and 2618 mg/kg, respectively. The values for the palmitate ester were >2500 and >5000 mg/kg; in a formulated syrup the po LD50 was reduced to 1950 mg/kg. The maximum daily tolerated dose of the hydrochloride in the dog and rat for as long as 1 yr was greater than 300 mg/kg but less than 600 mg/kg. Significant changes in bioclinical data in dogs treated with 300 mg/kg were confined to sporadic elevations in serum transaminase levels. At 600 mg/kg, in short-term studies, the effects of focal irritation were recognized in the mucosa of the stomach and gallbladder of the dog. No teratogenic effect or developmental retardation in the offspring of mouse or rat dams, or effect on the breeding performance of male and female rats was observed. In a comparable series of studies with the palmitate ester, essentially no effects due to the antibiotic were detected. A daily dose of 600 mg/kg was well tolerated in the dog and rat for 6 mo.

31-Norcycloartanol Fatty Acid Esters: Cholesteric Liquid Crystals from a Triterpene of Plant Origin

Abstract The triterpene 31-norcycloartanol, previously reported present in pollen of Taraxacum den leonis, was isolated from the ester fraction but not the free sterol fraction, of lipid extracts of this pollen. Even chain esters of this triterpene from the acetate to the palmitate were found to be mesomorphic. The acetate, butyrate, hexanoate and octanoate formed only a cholesteric mesophase while the decanoate, laurate, myristate and palmitate formed both smectic and cholesteric mesophases. Only the palmitate ester could be specifically detected by gas-liquid chromatography in the naturally occurring fraction, but the probability of other liquid crystalline forms in the complex ester mixture seemed very likely.

Fatty acyl-coA and fatty acyl-acyl carrier protein as acyl donors in the synthesis of lysophosphatidate and phosphatidate in escherichia coli

1. 1. A particulate fraction of Escherichia coli catalyzes the transfer of palmitate from palmityl-CoA and palmityl-acyl carrier protein to sn-glycero-3-phosphate. When a series of long-chain acyl thiolesters including myristyl-, palmityl-, palmitoleyl- and cis-vaccenyl-CoA and acyl carrier protein were tested in the acylation of sn-glycero-3-phosphate, the palmitate esters were the most effective substrates. 2. 2. Lysophosphatidate has been identified as the initial product formed from sn-glycero-3-phosphate and either palmityl-CoA or palmityl-acyl carrier protein. The lysophosphatidate can either be acylated to phosphatidic acid or be dephosphorylated to the monoglyceride. The extent to which both reactions occur depends on experimental conditions and on the nature of the acyl donor. 3. 3. Phosphatidic acid synthesis from sn-glycero-3-phosphate was observed in the presence of saturated or unsaturated CoA esters. 4. 4. When palmityl-acyl carrier protein was the only acyl donor present, hardly any phosphatidate was synthesized and the main products were lysophosphatidate and monoglyceride. In the additional presence of unsaturated acyl-acyl carrier protein phosphatidate was formed. This indicates the possibility of phosphatidate biosynthesis from sn-glycero-3-phosphate and acyl-acyl carrier protein esters. 5. 5. The acylation of 1-acyl- sn-glycero-3-phosphate by acyltransferases from E. coli occurred preferentially with unsaturated fatty acyl thiolesters. Especially, acyl-acyl carrier protein esters were used with great selectivity for the acyl portion in this acylation reaction. 6. 6. The palmitate thiolester of 4'-phosphopantetheine was not used as acyl donor to sn-glycero-3-phosphate under conditions in which acyl thiolesters of both CoA and acyl carrier protein are active. 7. 7. Some properties of the enzyme catalyzing the dephosphorylation of lysophosphatidate and phosphatidate are described.

Carnitine Ester Hydrolase of Rat Liver

Abstract Rat liver, kidney, pancreas, and small intestine have enzymes which hydrolyze fatty acid esters of carnitine. The liver enzyme, located in the microsomal fraction, was solubilized by sonic disruption and purified 18-fold by diethylaminoethyl cellulose chromatography and Sephadex gel filtration. The purified enzyme sedimented in the ultracentrifuge as a single protein with an s20,w of 4.5 S. The enzyme had maximum activity at pH 7.5 and hydrolyzed higher fatty acid (C6 to C18) esters of l-carnitine. d-Carnitine esters were not hydrolyzed. Esters of dl-carnitine were hydrolyzed only about one-half as efficiently as those of the l isomer. The enzyme did not hydrolyze palmitoyl coenzyme A, p-nitrophenyl palmitate, glycerol tripalmitate, and cholesterol palmitate, but it catalyzed the hydrolysis of glycerol monopalmitate to a slight extent. Among the l-carnitine esters, maximum rate of hydrolysis was obtained with the decanoate ester. The Km for decanoate ester was 3.2 x 10-3 m and for the palmitate ester 5 x 10-3 m. The enzyme was not affected by l-carnitine, dl-carnitine, d-carnitine, ethylenediaminetetraacetic acid, and Mg++ but it was inhibited by decanoyl-d-carnitine, Ca++, Cu++, NaF, sulfhydryl reagents, and sodium cholate, and it was activated by bovine serum albumin. The properties of carnitine ester hydrolase which distinguish it from microsomal esterase and microsomal lipase are discussed.

The biological activities of vitamin A acetate and vitamin A palmitate: experiments with chickens.

In the first experiment, 250 unsexed day-old chickens were given for 7 days a diet low in vitamin A based on white maize and soya bean meal. Then 100 chickens were given a single dose of 11, 960 IU retinyl acetate or 11, 510 IU retinyl palmitate and 50 were not dosed. After 68 h lots of 10 pooled livers were analysed for vitamin A. The birds given acetate had more vitamin A in the liver and a higher proportion of the dose stored than the palmitate groups, but the differences were not significant. In experiment 2 the sexes were equally divided within groups and the birds were similarly dosed. After 72 h liver vitamin A was significantly higher in groups given the acetate. In experiment 3 male and female chickens were separated and groups of each were given either the acetate or the palmitate ester. Vitamin A was measured in the liver after 3 days and after 4, 6, 7 and 8 weeks. It was significantly more in acetate-treated groups at 3 days and at 4 weeks. Compared with males, females had significantly greater vitamin A stores at 6, 7 and 8 weeks in groups given acetate and at 7 weeks in groups given palmitate. The next experiment was similar, but the basal diet contained 7-5 IU retinyl acetate in dry stabilised form and measurements were continued to 9 and 11 weeks. There was no significant difference in vitamin A stores between sexes or esters, or between dosed and non-dosed groups. Stores of vitamin A rose rapidly during the entire period. In experiments 5 and 6 male broiler chickens were given for 8 weeks the basal diet with 7.5 IU retinyl acetate or palmitate per g. Lots of 3 different body-weight ranges were taken from each treatment and liver vitamin A was measured. No significant effects of treatment on stores or bodyweight were found in either trial. In one trial liver weights were significantly higher in the acetate groups and the combined results showed significantly greater vitamin A stores in groups given acetate.-G. F. H. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Pentacylic triterpenes ofJurinea anatolic boiss. andJurinea consanguinea DC. Fruit

Pentacyclic triterpene alcohols, together with their acetate, myristate, and palmitate esters, comprise about 40% of the petroleum ether extract of the fruit (seed and pericarp) of twoJurinea species. All the triterpene esters and a porition of the free triterpene alcohols in theJ. anatolica extract are derived from the pericarp portion of the fruit. The triterpene alcohol moieties and their approximate percentage of the hydrolyzed extract ofJ. anatolica fruit are alpha-amyrin, 5%; beta-amyrin, 6%; lupeol, 6%; and psi-taraxasterol plus taraxasterol, 16%.J. consanguinea fruit extract yields essentially the same amount of the same five triterpene alcohols on hydrolysis. These concentrations of triterpenoid materials are believed to be the largest found in plant tissues.

SOME PHYSIOLOGIC CHARACTERISTICS OF ESTERS OF CETYL ALCOHOL

Palmitic, oleic, and butyric acid esters of cetyl alcohol were fed to mature rats. Cetyl palmitate was quantitatively excreted in the feces and produced no physiologic aberration. While cetyl oleate was 75% absorbable, it was of little value as an energy source and was partially excreted through the skin. Feeding of cetyl butyrate also induced seborrhea. Data on free fatty acids in gastrointestinal contents and on the specificity of seborrheic lipids indicate that cetyl esters are largely absorbed without hydrolysis, if the fatty acid moiety is readily absorbable, and excreted by way of the skin without modification.

SOME PHYSIOLOGIC CHARACTERISTICS OF ESTERS OF CETYL ALCOHOL

Palmitic, oleic, and butyric acid esters of cetyl alcohol were fed to mature rats. Cetyl palmitate was quantitatively excreted in the feces and produced no physiologic aberration. While cetyl oleate was 75% absorbable, it was of little value as an energy source and was partially excreted through the skin. Feeding of cetyl butyrate also induced seborrhea. Data on free fatty acids in gastrointestinal contents and on the specificity of seborrheic lipids indicate that cetyl esters are largely absorbed without hydrolysis, if the fatty acid moiety is readily absorbable, and excreted by way of the skin without modification.

The in vitro hydrolysis and esterification of vitamin A

1. 1. It has been demonstrated that liver homogenates and their nuclei, mitochondria, and fraction “X” are unable to hydrolyze the natural and palmitate esters of vitamin A. 2. 2. On wet weight basis, nuclei, mitochondria, and fraction “X” are approximately equal in their ability to hydrolyze vitamin A acetate; on a milligram of nitrogen basis, mitochondria and nuclei are most active. 3. 3. Homogenates of intestine and kidney are able to esterify vitamin A. Liver homogenates and their cellular components are unable to carry out this reaction.