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Last update: August 15, 2014.
1

40 CFR 721.3100 - Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine.  

Code of Federal Regulations, 2013 CFR

...false Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine...3100 Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine...generically as oligomeric silicic acid ester compound with a hydroxylalkylamine (PMN...

2013-07-01

2

40 CFR 721.3100 - Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine. 721.3100 Section 721.3100... § 721.3100 Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine. (a) Chemical substance...

2010-07-01

3

40 CFR 721.3100 - Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine. 721.3100 Section 721.3100... § 721.3100 Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine. (a) Chemical substance...

2009-07-01

4

Isolation of pure natural linoleic and linolenic acids as their methyl esters by adsorption fractionation on silicic acid  

Microsoft Academic Search

SummaryAn effective procedure is described for fractionating methyl esters of oils rich in linoleic and linolenic acids by adsorption\\u000a on silicic acid columns. Pure methyl linoleate from methyl esters of tobacco seed oil and pure methyl linolenate from methyl\\u000a esters of linseed and perilla oils were isolated by this procedure. These compounds were characterized by the usual physical\\u000a and chemical

R. W. Riemenschneider; S. F. Herb; Peter L. Nichols

1949-01-01

5

Omega-3-acid Ethyl Esters  

MedlinePLUS

Omega-3-acid ethyl esters are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount ... a fat-like substance) in your blood. Omega-3-acid ethyl esters are in a class of ...

6

Diffuse-reflectance Fouriertransform infrared spectroscopy of vegetable oil triglyceride adsorption on silicic acid  

Microsoft Academic Search

The adsorption of triglyceride by silicic acid from hexane miscellas was observed with diffuse-reflectance Fouriertransform\\u000a infrared spectroscopy. Triglyceride was adsorbed by hydrogen bonding to silanol groups through the ester carbonyl group. Addition\\u000a of isopropanol (IPA) to the triglyceride-hexane solution prior to adsorption resulted in unchanged triglyceride adsorption\\u000a on silicic acid despite IPA's ability to adsorb on silicic acid and hydrogen-bond

C. Adhikari; A. Proctor; G. D. Blyholder

1994-01-01

7

Fumaric acid esters in dermatology  

PubMed Central

Fumaric acid esters (FAE) are substances of interest in dermatology. FAE exert various activities on cutaneous cells and cytokine networks. So far only a mixture of dimethylfumarate (DMF) and three salts of monoethylfumarate (MEF) have gained approval for the oral treatment of moderate-to-severe plaque-type psoriasis in Germany. DMF seems to be the major active component. There is evidence that FAE are not only effective and safe in psoriasis but granulomatous non-infectious diseases like granuloma annulare, necrobiosis lipoidica and sarcoidosis. In vitro and animal studies suggest some activity in malignant melanoma as well.

Wollina, Uwe

2011-01-01

8

Crystallization Behavior of Fatty Acid Methyl Esters  

Microsoft Academic Search

Biodiesel from most agricultural feedstocks has flow properties that are prone to startup and operability problems during\\u000a cold weather. Biodiesel from soybean oil is generally a mixture of long-chain fatty acid alkyl esters composed of 0.150.20\\u000a mass fraction saturated esters (melting point [MP]?0C) mixed with unsaturated esters (MP<0C). This work investigates\\u000a the crystallization properties of two saturated fatty acid methyl

Robert O. Dunn

2008-01-01

9

Cyclopropane amino acid ester dipeptide sweeteners.  

PubMed

A series of esters of L-aspartyl-1-aminocyclopropane carboxylic acid has been prepared and their sweet tastes determined. The sweetest ester prepared was about 300 times sweeter than sucrose. An attempt to use basic conditions during preparation of the dipeptide allyl ester led to succinimide formation of the aspartyl peptide even though the beta-carboxyl group was protected by a t-butyl ester function. The X-ray structure of the propyl ester (1c) was determined and its conformation is discussed. PMID:3429129

Mapelli, C; Newton, M G; Ringold, C E; Stammer, C H

1987-10-01

10

Glycerol Glycoside Esters of Fatty Acids.  

National Technical Information Service (NTIS)

The patent application relates to compositions of matter containing esters of glycosides and 6 to 24 carbon atom fatty acids, which compositions are useful as surface-active agents. More particularly, this invention relates to compositions of matter obtai...

R. O. Feuge J. L. White M. L. Brown

1974-01-01

11

Kojic Acid and Esters as Insecticide Synergists.  

National Technical Information Service (NTIS)

Kojic acid and its esters have been found to be effective synergists for pyrethroid and carbamate insecticides on H. zea and S. frugiperda. Thus they may serve as replacements for the widely used methylene dioxyphenyl compounds such as piperonyl butoxide....

P. F. Dowd

1988-01-01

12

77 FR 21676 - Silicic Acid, Sodium Salt etc.; Tolerance Exemption  

Federal Register 2010, 2011, 2012, 2013

...FRL-9333-6] Silicic Acid, Sodium Salt etc.; Tolerance Exemption...for Silicic acid, sodium salt, reaction products with chlorotrimethylsilane...residues of Silicic acid, sodium salt, reaction products with chlorotrimethylsilane...approval under the Paperwork Reduction Act (PRA), 44...

2012-04-11

13

Thermoset polymer-layered silicic acid nanocomposites  

NASA Astrophysics Data System (ADS)

Nanocomposites are formed when phase mixing occurs on a nanometer length scale. Due to the improved phase morphology and interfacial properties, nanocomposites exhibit mechanical properties superior to conventional composites. Toyota researchers first demonstrated that organoclay could be exfoliated in a nylon-6 matrix to greatly improve the thermal and mechanical properties of the polymer, which has resulted in a practical application in the automobile industry. A great deal of research has been conducted on organic-inorganic hybrid composites in which smectite clays are used as reinforcement agents. However, little work has been devoted to derivatives of other layered inorganic solids. In the present work, the first examples of organic polymer-layered silicic acid nanocomposites have been prepared by formation of a cured epoxy polymer network in the presence of organo cation exchange forms of magadiite. The exfoliation of silicate nanolayers in the epoxy matrix was achieved by in-situ intragallery polymerization during the thermosetting process. In general, the tensile properties, solvent resistance, barrier properties and chemical stability of the polymer matrix are greatly improved by the embedded silicate nanolayers when the matrix is flexible (sub-ambient Tg). The improvement of properties are dependent on the silicate loading, the degree of nanolayer separation and interfacial properties. Interestingly, the exfoliation also affects the polymer elasticity in a favorable way. The mechanism leading to nanocomposite formation is proposed. One exfoliated epoxy-magadiite nanocomposite/composition possessed unique transparent optical properties. The exfoliation chemistry was successfully extended to the other members of the layered silicic acid family. A new approach also was developed to prepare thermoset epoxy polymer-layered silicate nanocomposites in which curing agents can be directly intercalated into the intragallery without the need for alkylammonium ions on the exchange sites. This new development has resulted in a greater improvement in the overall properties of thermoset polymer-clay nanocomposites. The exfoliation chemistry was extended further to other thermoset silicone polymer systems. The new polysiloxane-layered silicic acid nanocomposites were prepared with promising mechanical properties. Some fundamental chemistry and physics issues regarding nanocomposite formation were elucidated by this research work, particularly with regard to the relationship of microstructure and interfacial factors to the mechanical properties of the nanocomposites.

Wang, Zhen

14

40 CFR 721.4215 - Hexanedioic acid, diethenyl ester.  

Code of Federal Regulations, 2013 CFR

...may be subtracted in calculating the number of kilograms released. No more than...combination with the substances hexanoic acid, 2-ethyl-, ethenyl ester, neononanoic acid, ethenyl ester, and propanoic acid, 2,2-dimethyl-, ethenyl...

2013-07-01

15

40 CFR 721.5310 - Neononanoic acid, ethenyl ester.  

Code of Federal Regulations, 2013 CFR

...may be subtracted in calculating the number of kilograms released. No more than...combination with the substances hexanedioic acid, diethenyl ester, hexanoic acid, 2-ethyl-, ethenyl ester, and propanoic acid, 2,2-dimethyl-, ethenyl...

2013-07-01

16

Esters of valerenic acid as potential prodrugs  

PubMed Central

Valerenic acid (VA) is a ?2/3 subunit-specific modulator of ?-aminobutyric acid (GABA) type A (GABAA) receptors inducing anxiolysis. Here we analyze if VA-esters can serve as prodrugs and if different ester structures have different in vitro/in vivo effects. Modulation of GABAA receptors expressed in Xenopus oocytes was studied with 2-microelectrode-voltage-clamp. Anxiolytic effects of the VA-esters were studied on male C57BL/6N mice by means of the elevated plus maze-test; anticonvulsant properties were deduced from changes in seizure threshold upon pentylenetetrazole infusion. VA was detected in plasma confirming hydrolysis of the esters and release of VA in vivo. Esterification significantly reduced the positive allosteric modulation of GABAA (?1?3?2S) receptors in vitro. in vivo, the studied VA-ester derivatives induced similar or even stronger anxiolytic and anticonvulsant action than VA. While methylation and propylation of VA resulted in faster onset of anxiolysis, the action of VA-ethylester was longer lasting, but occurred with a significant delay. The later finding is in line with the longer lasting anticonvulsant effects of this compound. The estimated VA plasma concentrations provided first insight into the release kinetics from different VA-esters. This might be an important step for its future clinical application as a potential non-sedative anxiolytic and anticonvulsant.

Hintersteiner, Juliane; Haider, Maximilian; Luger, Denise; Schwarzer, Christoph; Reznicek, Gottfried; Jager, Walter; Khom, Sophia; Mihovilovic, Marko D.; Hering, Steffen

2014-01-01

17

Esters of valerenic acid as potential prodrugs.  

PubMed

Valerenic acid (VA) is a ?2/3 subunit-specific modulator of ?-aminobutyric acid (GABA) type A (GABAA) receptors inducing anxiolysis. Here we analyze if VA-esters can serve as prodrugs and if different ester structures have different in vitro/in vivo effects. Modulation of GABAA receptors expressed in Xenopus oocytes was studied with 2-microelectrode-voltage-clamp. Anxiolytic effects of the VA-esters were studied on male C57BL/6N mice by means of the elevated plus maze-test; anticonvulsant properties were deduced from changes in seizure threshold upon pentylenetetrazole infusion. VA was detected in plasma confirming hydrolysis of the esters and release of VA in vivo. Esterification significantly reduced the positive allosteric modulation of GABAA (?1?3?2S) receptors in vitro. in vivo, the studied VA-ester derivatives induced similar or even stronger anxiolytic and anticonvulsant action than VA. While methylation and propylation of VA resulted in faster onset of anxiolysis, the action of VA-ethylester was longer lasting, but occurred with a significant delay. The later finding is in line with the longer lasting anticonvulsant effects of this compound. The estimated VA plasma concentrations provided first insight into the release kinetics from different VA-esters. This might be an important step for its future clinical application as a potential non-sedative anxiolytic and anticonvulsant. PMID:24680924

Hintersteiner, Juliane; Haider, Maximilian; Luger, Denise; Schwarzer, Christoph; Reznicek, Gottfried; Jger, Walter; Khom, Sophia; Mihovilovic, Marko D; Hering, Steffen

2014-07-15

18

Esters of dicarboxylic acids as additives for lubricating oils  

Microsoft Academic Search

Five samples of dibasic acid esters with varied chemical structures were synthesized. These included didecyl carbonate, didecyl adipate and didecyl sebacate as well as modern oligomeric esters of adipic acid and sebacic acid. These esters were tested in terms of their suitability as additives of fully synthetic engine oils. It was noted that an addition of 10% of the respective

S. Gryglewicz; M. Stankiewicz; F. A. Oko; I. Surawska

2006-01-01

19

Caffeic Acid Phenethyl Ester and Therapeutic Potentials  

PubMed Central

Caffeic acid phenethyl ester (CAPE) is a bioactive compound of propolis extract. The literature search elaborates that CAPE possesses antimicrobial, antioxidant, anti-inflammatory, and cytotoxic properties. The principal objective of this review article is to sum up and critically assess the existing data about therapeutic effects of CAPE in different disorders. The findings elaborate that CAPE is a versatile therapeutically active polyphenol and an effective adjuvant of chemotherapy for enhancing therapeutic efficacy and diminishing chemotherapy-induced toxicities.

Karim, Sabiha; Akram, Muhammad Rouf; Khan, Shujaat Ali; Azhar, Saira; Mumtaz, Amara; Bin Asad, Muhammad Hassham Hassan

2014-01-01

20

Silicic acid uptake and incorporation by natural marine phytoplankton populations  

Microsoft Academic Search

Germanic acid (⁶⁸Ge) was used as a tracer to study the uptake and incorporation of silicic acid by natural phytoplankton populations in the Gulf of California. The technique was useful in measuring silicic acid incorporation rates as low as 0.5 nM h⁻¹. The incorporation followed saturation kinetics. K\\/sub s\\/ values at two stations were 1.59 and 2.53 ..mu..M. The incorporation

F. Azam; S. W. Chisholm

1976-01-01

21

Kinetics of sulphuric acid leaching of a zinc silicate calcine  

Microsoft Academic Search

Recent developments of acid leaching and solvent extraction of zinc silicate ores have produced renewed commercial interest. However, the leaching kinetics of these concentrates has received little attention. This work, therefore, addresses the leaching of a zinc silicate concentrate in sulphuric acid. The effects of particle size (0.0380.075mm), temperature (3050C) and initial acid concentration (0.21.0mol\\/L) were studied. The results show

A. D. Souza; P. S. Pina; E. V. O. Lima; C. A. da Silva; V. A. Leo

2007-01-01

22

Role of Fulvic Acids During the Weathering of Silicate Minerals.  

National Technical Information Service (NTIS)

The processes of migration and accumulation of aluminum in different crusts produced from weathering are studied by analyzing the decomposition conditions of silicate minerals by humic soil acids. (Author)

Y. I. Sokolova

1973-01-01

23

Silicic-acid uptake in diatoms studied with [ 68 Ge]germanic acid as tracer  

Microsoft Academic Search

Uptake of silicic acid in the diatoms Navicula pelliculosa and Nitzschia alba was studied, using the natural isotope, 28Si, or a radioisotope, 31Si. The rate of uptake of silicic acid was also determined by using [68Ge]germanic acid as a tracer of silicic acid. At a given silicicacid concentration in the growth medium, the fractions of [68Ge]germanic acid taken up followed

Farooq Azam

1974-01-01

24

Synthesis and Immunomodulating Activity of New Amino Acid Derivatives of Glycyrrhizic Acid and Its Methyl Ester  

Microsoft Academic Search

New amino acid derivatives of glycyrrhizic acid and its methyl ester were selectively synthesized using active N-succinimide esters. The compounds with residues of glycine ethyl ester and alanine methyl and butyl esters increased the level of agglutinins and hemolysins in blood serum of mice two- to threefold in comparison with the control upon parenteral administration at a dose of 2

R. M. Kondratenko; L. A. Baltina; E. V. Vasil'eva; Kh. M. Nasyrov; R. M. Kireeva; N. Zh. Baschenko; S. M. Fridman; G. A. Tolstikov

2004-01-01

25

Long Chain a -phosphono fatty acids, salts and esters  

Microsoft Academic Search

A series of ?-phosphono fatty acids and their salts and esters was prepared from pelargonic, capric, lauric, myristic, palmitic,\\u000a and stearic acids. In comparison to corresponding?-sulfo fatty acids the?-phosphono fatty acids are white solids of higher melting point, weaker acids, less hygroscopic, have a lower critical micelle\\u000a concentration and are less resistant to hard water. Methyl, isopropyl, and amyl esters

E. W. Maurer; A. J. Stirton; W. C. Ault; J. K. Weil

1964-01-01

26

MICROBIAL TRANSFORMATION OF ESTERS OF CHLORINATED CARBOXYLIC ACIDS  

EPA Science Inventory

Two groups of compounds were selected for microbial transformation studies. In the first group were carboxylic acid esters having a fixed aromatic moiety and an increasing length of the alkyl component. Ethyl esters of chlorine-substituted carboxylic acids were in the second grou...

27

Preparation of {alpha},{beta}-unsaturated carboxylic acids and esters  

DOEpatents

Disclosed is a process for the preparation of {alpha},{beta}-unsaturated carboxylic acids and esters thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic acid, ester or anhydride in the presence of a catalyst comprising an oxide of niobium.

Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.

1998-09-15

28

Adamantane dicarboxylic acid esters as possible additives to semisolid lubricants  

Microsoft Academic Search

The high efficiency of adamantane carboxylic acid esters as antiwear additives to lubricating compounds based on polysiloxane liquids has been demonstrated. Dibutyl and dihexyl esters of 5,7-dimethyl-1,3-adainantane dicarboxylic acid, increasing by several factors the efficiency of a semisolid lubricant based on liquid methyldichlorophenylsiloxane, have been synthesized and characterized.

I. A. Novikova; T. N. Dolgopolova; A. D. Apryatkin

1993-01-01

29

Preparation of .alpha.,.beta.-unsaturated carboxylic acids and esters  

DOEpatents

Disclosed is a process for the preparation of .alpha.,.beta.-unsaturated carboxylic acids and esters thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic acid, ester or anhydride in the presence of a catalyst comprising an oxide of niobium.

Gogate, Makarand Ratnakar (Durham, NC); Spivey, James Jerry (Cary, NC); Zoeller, Joseph Robert (Kingsport, TN)

1998-01-01

30

Granuloma annulare disseminatum responding to fumaric acid esters.  

PubMed

A 40-year-old man suffered from disseminated granuloma annulare not responding to topical steroids and PUVA-therapy. He was treated with fumaric acid esters and achieved a partial response within 3 weeks, a complete remission after 12 weeks. The literature on fumaric acid esters in granuloma annulare is reviewed. PMID:19265625

Wollina, Uwe

2008-01-01

31

21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.  

Code of Federal Regulations, 2012 CFR

...Partial phosphoric acid esters of polyester resins. 175.260 Section 175.260 Food...Partial phosphoric acid esters of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section and...

2012-04-01

32

21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.  

Code of Federal Regulations, 2011 CFR

...Partial phosphoric acid esters of polyester resins. 175.260 Section 175.260 Food...Partial phosphoric acid esters of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section and...

2011-04-01

33

40 CFR 721.8160 - Propanoic acid, 2,2-dimethyl-, ethenyl ester.  

Code of Federal Regulations, 2013 CFR

...may be subtracted in calculating the number of kilograms released. No more than...combination with the substances hexanedioic acid, diethenyl ester, hexanoic acid, 2-ethyl-, ethenyl ester, and neononanoic acid, ethenyl ester, the quotient...

2013-07-01

34

40 CFR 721.10165 - Carbonotrithioic acid, bis(phenylmethyl) ester.  

Code of Federal Regulations, 2010 CFR

...false Carbonotrithioic acid, bis(phenylmethyl) ester. 721.10165 Section 721...10165 Carbonotrithioic acid, bis(phenylmethyl) ester. (a) Chemical substance...identified as carbonotrithioic acid, bis(phenylmethyl) ester (PMN P-08-138;...

2010-07-01

35

40 CFR 721.7770 - Alkylphenoxypoly(oxyethylene) sulfuric acid ester, substituted amine salt.  

Code of Federal Regulations, 2010 CFR

...sulfuric acid ester, substituted amine salt. 721.7770 Section 721.7770 ...sulfuric acid ester, substituted amine salt. (a) Chemical substance and significant...sulfuric acid ester, substituted amine salt (PMN P-92-396) is subject to...

2010-07-01

36

40 CFR 721.7770 - Alkylphenoxypoly(oxyethylene) sulfuric acid ester, substituted amine salt.  

Code of Federal Regulations, 2012 CFR

...sulfuric acid ester, substituted amine salt. 721.7770 Section 721.7770 ...sulfuric acid ester, substituted amine salt. (a) Chemical substance and significant...sulfuric acid ester, substituted amine salt (PMN P-92-396) is subject to...

2012-07-01

37

40 CFR 721.7290 - Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. 721.7290...721.7290 Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. (a) Chemical...identified as propanoic acid, 2-(trimethoxysilyl)-, ethyl ester (PMN...

2009-07-01

38

40 CFR 721.7290 - Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. 721.7290...721.7290 Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. (a) Chemical...identified as propanoic acid, 2-(trimethoxysilyl)-, ethyl ester (PMN...

2013-07-01

39

40 CFR 721.7290 - Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. 721.7290...721.7290 Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. (a) Chemical...identified as propanoic acid, 2-(trimethoxysilyl)-, ethyl ester (PMN...

2010-07-01

40

A chromatographic method for the analysis of propylene glycol fatty acid esters in shortenings containing mono- and diglycerides  

Microsoft Academic Search

A procedure is described for the separation, identification, and quantitative estimation of propylene glycol mono- and diesters\\u000a of lauric, myristic, palmitic, stearic, and oleic acids in shortenings and lard containing mono- and diglycerides. Lipid classes\\u000a are separated on a silicic acid column, and individual esters are estimated by gas chromatography. Analyses of several control\\u000a mixtures and commercial samples are reported.

Madhu R. Sahasrabudhe; J. J. Legari

1968-01-01

41

Preparation of pentafluorosulfanyl (SF5) pyrrole carboxylic acid esters.  

PubMed

Pyrrole derivatives bearing a pentafluorosulfanyl group are currently unknown. In this paper, a facile preparation of SF5-substituted pyrrole carboxylic acid esters in good yield is reported. Utilizing the cycloaddition of an azomethine ylide to pentafluorosulfanylalkynes, a series of dihydropyrroles were prepared and oxidized to the respective 1-tert-butyl-4-(pentafluorosulfanyl)pyrrole-2-carboxylic acid esters in good yield. Further treatment of these pyrroles with catalytic triflic acid allowed removal of the tert-butyl group. PMID:19555094

Dolbier, William R; Zheng, Zhaoyun

2009-08-01

42

Reactions of iodotrimethylsilane with esters of aromatic and araliphatic acids  

SciTech Connect

A study was made of the reactions of iodotrimethylsilane with esters of aromatic and araliphatic acids, leading to the corresponding trimethylsilyl esters. In the reaction of iodotrimethylsilane with (trimethoxysilyl)methyl (aryloxy)acetates all three types of C-O bonds are broken.

Voronkov, M.G.; Dolmaa, G.; Putilova, G.G.; Dubinskaya, E.I.

1986-04-10

43

21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.  

Code of Federal Regulations, 2010 CFR

...of fatty acids. Glyceryl-lacto esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely...conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860...

2010-01-01

44

21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.  

Code of Federal Regulations, 2010 CFR

...of fatty acids. Glyceryl-lacto esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely...conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860...

2009-04-01

45

Solvent Effects on the Protonation Constants of Some ? Amino Acid Esters in 1,4DioxaneWater Mixtures  

Microsoft Academic Search

The stoichiometric protonation constants of some ?-amino acid esters (glycine methyl ester, glycine t-butyl ester, l-valine methyl ester, l-valine ethyl ester, l-valine t-butyl ester, l-serine methyl ester, l-serine ethyl ester, l-leucine methyl ester, l-leucine ethyl ester, l-leucine t-butyl ester, l-alanine methyl ester, l-alanine benzyl ester, l-phenylalanine methyl ester, l-phenylalanine ethyl ester, and l-phenylalanine t-butyl ester) in water and 20%, 40%,

Alev Do?an; Nazife Aslan; Esin Canel; Esma K?l?

2010-01-01

46

[Test and analysis of acrylic acid ester in industry pipelines].  

PubMed

A new quality and quantity analyzing method for waste gas from chemical industry, especially for acrylic acid ester using air-sampling combined with GC/MS and honeywell air purifier system was firstly advanced in this paper. According to the experiments, the maximum disposal capability of the honeywell air purifier system for acrylic acid ester gas was calculated as about 1 kg x h(-1) and the feasibility and validity of the method was also proved by parallel tests. PMID:22468533

Wu, Bin; Zhang, Hong-Yan; Lu, Lin-Guang

2011-12-01

47

Dicarboxylic acid esters as components of modern synthetic oils  

Microsoft Academic Search

Purpose The paper presents the results of research carried out on esters of carbonic, adipic, and sebacic acids with respect to their use as components of fully synthetic lubricating oil produced from a polyalphaolefin base. Straight dicarboxylic acid esters were synthesized in a transesterification reaction of dimethyl carbonate, dimethyl adipate, and dimethyl sebacate with 2-ethylhexanol and 3,5,5-trimethylhexanol. Design\\/methodology\\/approach

S. Gryglewicz; F. A. Oko

2005-01-01

48

Eicosapentaenoic acid geometrical isomer artifacts in heated fish oil esters  

Microsoft Academic Search

Gas liquid chromatography (GLC) on polar capillary columns showed that the ester of eicosapentaenoic acid (EPA) in distilled\\u000a fish oil methyl and ethyl esters sometimes is accompanied by several artifacts. The same EPA artifacts did not arise from\\u000a saponification and\\/or esterification but were formed in a significantly high yield during prolonged heating of the authentic\\u000a acid. Physicochemical studies, isolation and

R. C. Wijesundera; W. M. N. Ratnayake; R. G. Ackman

1989-01-01

49

Different mechanisms of silicic acid leakage and their biogeochemical consequences  

NASA Astrophysics Data System (ADS)

the modern ocean, silicic acid is effectively trapped in the Southern Ocean. According to the silicic acid leakage hypothesis, a loosening of this trapping may have contributed to low atmospheric CO2 during glacial times. Using a model with dynamical feedbacks in ocean physics and biology, we explore three distinct mechanisms to loosen the trapping and trigger silicic acid leakage from the Southern Ocean: sea ice expansion, weaker winds, and iron addition. The basic idea of the iron addition mechanism was previously explored using a simple box model. Here we confirm the main results of the earlier work and demonstrate further that sea ice expansion and weaker southern westerlies can also trigger silicic acid leakage. The three mechanisms are not mutually exclusive, and their biogeochemical consequences are dissimilar in terms of the spatial patterns of Si:N uptake and the relative changes in opal and particulate organic carbon fluxes both in and outside the Southern Ocean. While it is not entirely clear how sea ice, winds, and iron deposition were different during the last glacial period compared to today, we examine the synergistic effects of these three triggers in one simulation. In this simulation, the combination of sea ice and iron reproduces the north-south dipole of productivity recorded in export production proxies, but effects of the iron perturbation seem to dominate the overall biogeochemical response.

Matsumoto, Katsumi; Chase, Zanna; Kohfeld, Karen

2014-03-01

50

Fatty acid phytyl ester synthesis in chloroplasts of Arabidopsis.  

PubMed

During stress or senescence, thylakoid membranes in chloroplasts are disintegrated, and chlorophyll and galactolipid are broken down, resulting in the accumulation of toxic intermediates, i.e., tetrapyrroles, free phytol, and free fatty acids. Chlorophyll degradation has been studied in detail, but the catabolic pathways for phytol and fatty acids remain unclear. A large proportion of phytol and fatty acids is converted into fatty acid phytyl esters and triacylglycerol during stress or senescence in chloroplasts. We isolated two genes (PHYTYL ESTER SYNTHASE1 [PES1] and PES2) of the esterase/lipase/thioesterase family of acyltransferases from Arabidopsis thaliana that are involved in fatty acid phytyl ester synthesis in chloroplasts. The two proteins are highly expressed during senescence and nitrogen deprivation. Heterologous expression in yeast revealed that PES1 and PES2 have phytyl ester synthesis and diacylglycerol acyltransferase activities. The enzymes show broad substrate specificities and can employ acyl-CoAs, acyl carrier proteins, and galactolipids as acyl donors. Double mutant plants (pes1 pes2) grow normally but show reduced phytyl ester and triacylglycerol accumulation. These results demonstrate that PES1 and PES2 are involved in the deposition of free phytol and free fatty acids in the form of phytyl esters in chloroplasts, a process involved in maintaining the integrity of the photosynthetic membrane during abiotic stress and senescence. PMID:22623494

Lippold, Felix; vom Dorp, Katharina; Abraham, Marion; Hlzl, Georg; Wewer, Vera; Yilmaz, Jenny Lindberg; Lager, Ida; Montandon, Cyrille; Besagni, Cline; Kessler, Felix; Stymne, Sten; Drmann, Peter

2012-05-01

51

Thermal and mechanical properties of fatty acid starch esters.  

PubMed

The current study examined thermal and mechanical properties of fatty acid starch esters (FASEs). All highly soluble esters were obtained by the sustainable, homogeneous transesterification of fatty acid vinyl esters in dimethylsulfoxide (DMSO). Casted films of products with a degree of substitution (DS) of 1.40-1.73 were compared with highly substituted ones (DS 2.20-2.63). All films were free of any plasticizer additives. Hydrophobic surfaces were characterized by contact angle measurements. Dynamic scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) revealed thermal transitions (T(g), T(m)) which were influenced by the internal plasticizing effect of the ester groups. Thermal gravimetric analysis (TGA) measurements showed the increased thermal stability toward native starch. Tensile tests revealed the decreasing strength and stiffness of the products with increasing ester-group chain length while the elongation increased up to the ester group laurate and after that decreased. Esters of the longest fatty acids, palmitate and stearate turned out to be brittle materials due to super molecular structures of the ester chains such as confirmed by X-ray. Summarized products with a DS 1.40-1.73 featured more "starch-like" properties with tensile strength up to outstanding 43 MPa, while products with a DS >2 behaved more "oil-like". Both classes of esters should be tested as a serious alternative to commercial starch blends and petrol-based plastics. The term Cnumber is attributed to the number of total C-Atoms of the fatty acid (e.g. C6=Hexanoate). PMID:24507367

Winkler, H; Vorwerg, W; Rihm, R

2014-02-15

52

40 CFR 417.140 - Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids...  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids subcategory. 417.140 Section 417.140 Protection...POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory §...

2010-07-01

53

40 CFR 417.140 - Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids...  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids subcategory. 417.140 Section 417.140 Protection...POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory §...

2009-07-01

54

21 CFR 573.640 - Methyl esters of higher fatty acids.  

Code of Federal Regulations, 2010 CFR

...Docosahexanoic acid, eicosapentanoic acid, linoleic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid, and stearic acid, and lesser amounts of the associated acid esters. (b) The food additive meets the following...

2009-04-01

55

21 CFR 573.640 - Methyl esters of higher fatty acids.  

Code of Federal Regulations, 2010 CFR

...Docosahexanoic acid, eicosapentanoic acid, linoleic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid, and stearic acid, and lesser amounts of the associated acid esters. (b) The food additive meets the following...

2010-04-01

56

Biological and therapeutic effects of ortho-silicic acid and some ortho-silicic acid-releasing compounds: New perspectives for therapy.  

PubMed

Silicon (Si) is the most abundant element present in the Earth's crust besides oxygen. However, the exact biological roles of silicon remain unknown. Moreover, the ortho-silicic acid (H4SiO4), as a major form of bioavailable silicon for both humans and animals, has not been given adequate attention so far. Silicon has already been associated with bone mineralization, collagen synthesis, skin, hair and nails health atherosclerosis, Alzheimer disease, immune system enhancement, and with some other disorders or pharmacological effects. Beside the ortho-silicic acid and its stabilized formulations such as choline chloride-stabilized ortho-silicic acid and sodium or potassium silicates (e.g. M2SiO3; M= Na,K), the most important sources that release ortho-silicic acid as a bioavailable form of silicon are: colloidal silicic acid (hydrated silica gel), silica gel (amorphous silicon dioxide), and zeolites. Although all these compounds are characterized by substantial water insolubility, they release small, but significant, equilibrium concentration of ortho-silicic acid (H4SiO4) in contact with water and physiological fluids. Even though certain pharmacological effects of these compounds might be attributed to specific structural characteristics that result in profound adsorption and absorption properties, they all exhibit similar pharmacological profiles readily comparable to ortho-silicic acid effects. The most unusual ortho-silicic acid-releasing agents are certain types of zeolites, a class of aluminosilicates with well described ion(cation)-exchange properties. Numerous biological activities of some types of zeolites documented so far might probably be attributable to the ortho-silicic acid-releasing property. In this review, we therefore discuss biological and potential therapeutic effects of ortho-silicic acid and ortho-silicic acid -releasing silicon compounds as its major natural sources. PMID:23298332

Jurki?, Lela Munjas; Cepanec, Ivica; Paveli?, Sandra Kraljevi?; Paveli?, Kreimir

2013-01-01

57

Fragrance material review on carbonic acid, methyl phenylmethyl ester.  

PubMed

A toxicologic and dermatologic review of carbonic acid, methyl phenylmethyl ester when used as a fragrance ingredient is presented. Carbonic acid, methyl phenylmethyl ester is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for carbonic acid, methyl phenylmethyl ester were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414647

McGinty, D; Letizia, C S; Api, A M

2012-09-01

58

Polymerization of amino acid methyl esters via their copper complexes  

Microsoft Academic Search

Polymerization of glycine methyl ester catalyzed by cupric ions in organic solvents yields oligoglycines with a degree of polymerization up to nine. With a trifunctional amino acid, the yeild and degree of polymerization were much lower. Extension of this reaction to an aqueous medium was not successful even when copper ions were complexed with substances like montmorillonite or fatty acids.

A. Brack; D. Louembe; G. Spach

1975-01-01

59

Tunable acid-sensitive ester protecting groups in oligosaccharide synthesis.  

PubMed

A series of acid-cleavable ester-type protecting groups, with acid-sensitivity profiles parallel to those of 2-naphthylmethyl (NAP) or p-methoxybenzyl (PMB) ether, were designed and TFA in toluene was identified as a technically simple and effective deblocking cocktail for their global removal in the context of oligosaccharide synthesis. PMID:24519721

Li, Yao; Liu, Xinyu

2014-03-25

60

Mobilization of Arsenite by Competitive Interaction with Silicic Acid  

Microsoft Academic Search

Due to the acute toxicity of As, mobilization of even a small fraction of As into surface and ground waters used as a source for drinking water represents a substantial risk to human health. Here we evaluate the mobilization of arsenite (As(III)) from the Fe-(hydr)oxide min- eral goethite (a-FeOOH) through competitive displacement by silicic acid, a naturally occurring and ubiquitous

Todd P. Luxton; Christopher J. Tadanier; Matthew J. Eick

2006-01-01

61

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Boric acid, alkyl and substituted alkyl esters...Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl esters... (1) The chemical substance boric acid, alkyl and substituted...

2010-07-01

62

40 CFR 721.4250 - Hexanoic acid, 2-ethyl-, ethenyl ester.  

Code of Federal Regulations, 2013 CFR

...may be subtracted in calculating the number of kilograms released. No more than...combination with the substances hexanedioic acid, diethenyl ester, neononanoic acid, ethenyl ester, and propanoic acid, 2,2-dimethyl-, ethenyl...

2013-07-01

63

Caffeic acid esters and lignans from Piper sanguineispicum.  

PubMed

Three new caffeic acid esters (1-3), four new lignans (4-7), and the known compounds (7'S)-parabenzlactone (8), dihydrocubebin (9), and justiflorinol (10) have been isolated from leaves of Piper sanguineispicum. Their structures were determined by spectroscopic methods, including 1D and 2D NMR, HRCIMS, CD experiments, and chemical methods. Compounds 1-10 were assessed for their antileishmanial potential against axenic amastigote forms of Leishmania amazonensis. Caffeic acid esters 1 and 3 exhibited the best antileishmanial activity (IC(50) 2.0 and 1.8 ?M, respectively) with moderate cytotoxicity on murine macrophages. PMID:20954722

Cabanillas, Billy Joel; Le Lamer, Anne-Ccile; Castillo, Denis; Arevalo, Jorge; Rojas, Rosario; Odonne, Guillaume; Bourdy, Genevive; Moukarzel, Batrice; Sauvain, Michel; Fabre, Nicolas

2010-11-29

64

Fatty acids, fatty alcohols, wax esters, and methyl esters from Crambe abyssinica and Lunaria annua seed oils  

Microsoft Academic Search

Crambe abyssinica andLunaria annua, members of the Cruciferae family, have seed oil glycerides containing ca. 5565% of C22 and C24 unsaturated fatty acids. Fatty acids were prepared by saponification; fatty alcohols, by sodium reduction of glycerides;\\u000a liquid wax esters, byp-toluenesulfonic acid-catalyzed reaction of fatty acids with fatty alcohols; and methyl esters, by reaction of fatty acids\\u000a with diazomethane. Solid hydrogenated

T. K. Miwa; I. A. Wolff

1963-01-01

65

Quantification method of size distribution of polysilicic acid in supersaturated silicic acid solution.  

PubMed

In order to estimate the absolute size distribution of polysilicic acid particles in geothermal waters, the distribution coefficient (K(av)) of gel permeation chromatography (GPC) for polysilicic acid particles and the hydrodynamic radius for the same polysilicic acid particles from Dynamic Light Scattering (DLS) are combined to quantify the particle size. From the combination, a quantitative relationship between the K(av) from GPC and the hydrodynamic radius for polysilicic acid from DLS was built up. Using this relationship, the change in particle size of polysilicic acid formed during the polymerization of silicic acid at pH 8 and 9 (initial silicic acid concentration: 800 ppm as SiO2) was examined. The result showed that polysilicic acid grew to 500 and 1000 nm by 5 h at pH 9 and 8, respectively. It was found that aluminum affects the growth of polysilicic acid particles, and that the effect depends on the pH. The proposed method in this study has been proved to be valid to measure the size of polysilicic acid during the polymerization of silicic acid in solutions with relatively low silicic acid concentration, such as geothermal water. PMID:23474723

Otsu, Emi; Etou, Mayumi; Ohashi, Hironori; Nishida, Ikuko; Bai, Shuquin; Okaue, Yoshihiro; Yokoyama, Takushi

2013-01-01

66

40 CFR 721.990 - 1,4-Benzedicarboxylic acid, dimethyl ester, polymer with 1,4 - butanediol, cyclized.  

Code of Federal Regulations, 2010 CFR

...4-Benzedicarboxylic acid, dimethyl ester, polymer with 1,4 - butanediol, cyclized...4-Benzedicarboxylic acid, dimethyl ester, polymer with 1,4 - butanediol, cyclized...4-benzedicarboxylic acid, dimethyl ester, polymer with 1,4 - butanediol,...

2010-07-01

67

Diffusion of propionic acid ethyl ester (1); air (2)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Brnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) propionic acid ethyl ester; (2) air

Winkelmann, J.

68

Diffusion of propionic acid pentyl ester (1); air (2)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Brnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) propionic acid pentyl ester; (2) air

Winkelmann, J.

69

Diffusion of propionic acid methyl ester (1); air (2)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Brnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) propionic acid methyl ester; (2) air

Winkelmann, J.

70

Diffusion of propionic acid isobutyl ester (1); air (2)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Brnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) propionic acid isobutyl ester; (2) air

Winkelmann, J.

71

Diffusion of propionic acid butyl ester (1); air (2)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Brnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) propionic acid butyl ester; (2) air

Winkelmann, J.

72

Treatment of disseminated granuloma annulare with fumaric acid esters  

Microsoft Academic Search

BACKGROUND: Granuloma annulare is a granulomatous disease of unknown etiology. Various therapies have been tried in disseminated granuloma annulare (DGA), including corticosteroids, several variants of psoralen plus ultraviolet-A radiation, ultraviolet- A1 radiation, systemic retinoids, and dapsone, with variable success. We report a patient with recalcitrant DGA who was treated with fumaric acid esters (FAE). CASE PRESENTATION: A 40-year old Caucasian

Alexander Kreuter; Thilo Gambichler; Peter Altmeyer; Norbert H Brockmeyer

2002-01-01

73

The biosynthesis of benzoic acid glucosinolate esters in Arabidopsis thaliana  

Microsoft Academic Search

The siliques and seeds of Arabidopsis thaliana accumulate a series of glucosinolates containing an alkyl side chain of varying length with a terminal benzoate ester function. The biosynthesis of these unusual nitrogen- and sulfur-containing natural products was investigated by feeding isotopically-labeled precursors to detached flowering stems. Glucosinolates were extracted, purified and analyzed by tandem mass spectrometry. Phenylalanine and benzoic acid

Gerson Graser; Neil J. Oldham; Paul D. Brown; Ulrike Temp; Jonathan Gershenzon

2001-01-01

74

Potential synthetic lubricants: Esters of C 18 -saturated cyclic acids  

Microsoft Academic Search

A series of 16 esters of C18-saturated cyclic acids (HCal) were prepared, and partial evaluation showed that several have qualities that recommend them\\u000a as potential low-temp lubricants. Starting materials used were primary, straight, and branched chain alcohols C4C7; perfluoro alcohols; phenol; cyclohexanol; and C18-saturated cyclic alcohols prepared from cyclic acids. Viscosities were measured at ?40, 100, and 210F. Their viscosity

J. P. Friedrich; E. W. Bell; L. E. Gast

1965-01-01

75

Encapsulating fatty acid esters of bioactive compounds in starch  

NASA Astrophysics Data System (ADS)

Interest in the use of many bioactive compounds in foods is growing in large part because of the apparent health benefits of these molecules. However, many of these compounds can be easily degraded during processing, storage, or their passage through the gastrointestinal tract before reaching the target site. In addition, they can be bitter, acrid, or astringent, which may negatively affect the sensory properties of the product. Encapsulation of these molecules may increase their stability during processing, storage, and in the gastrointestinal tract, while providing controlled release properties. The ability of amylose to form inclusion complexes and spherulites while entrapping certain compounds has been suggested as a potential method for encapsulation of certain molecules. However, complex formation and spherulitic crystallization are greatly affected by the type of inclusion molecules, type of starch, and processing conditions. The objectives of the present investigation were to: (a) study the effect of amylose, amylopectin, and intermediate material on spherulite formation and its microstructure; (b) investigate the formation of amylose and high amylose starch inclusion complexes with ascorbyl palmitate, retinyl palmitate, and phytosterol esters; (c) evaluate the ability of spherulites to form in the presence of fatty acid esters and to entrap ascorbyl palmitate, retinyl palmitate, and phytosterol esters; and (d) evaluate the effect of processing conditions on spherulite formation and fatty acid ester entrapment. Higher ratios of linear to branched molecules resulted in the formation of more and rounder spherulites with higher heat stability. In addition to the presence of branches, it appears that spherulitic crystallization is also affected by other factors, such as degree of branching, chain length, and chain length distribution. Amylose and Hylon VII starch formed inclusion complexes with fatty acid esters of ascorbic acid, retinol, or phytosterols. However, only retinyl palmitate formed a complex with amylopectin. In general, ascorbyl palmitate resulted in the highest complexation, followed by retinyl palmitate and phytosterol ester. The presence of native lipids in Hylon VII starch did not inhibit complex formation. On the contrary, native lipids appear to increase the complexation yield and thermal stability of the starch-fatty acid ester inclusion complexes, possibly due to the formation of ternary complexes. From the three fatty acid esters studied, only ascorbyl palmitate was entrapped in starch spherulites. Various structures including round spherulites, various sizes of torus-shape spherulites, non-spherulitic birefringent and non-birefringent particles, "balloon" morphologies, and gel-like material were formed depending on processing conditions. However, only the torus-shape spherulites, and some non-spherulitic birefringent and non-birefringent particles showed ascorbyl palmitate entrapment. The % yield of the precipitate increased with higher % of added Hylon VII, and decreased with higher heating temperature and faster cooling rates. The amount of entrapped ascorbyl palmitate in the starch precipitate seems to be governed by the amount of this compound added during processing. This study showed that starch can form inclusion complexes with fatty acid esters which may be used for the delivery of certain bioactive molecules. In addition, encapsulation of fatty acid esters in starch spherulites may be a good potential delivery system for water soluble bioactive molecules. However, further research is necessary to gain a better understanding of the type of molecules that can be entrapped in starch spherulites, and the factors affecting spherulitic crystallization and bioactive compound entrapment.

Lay Ma, Ursula Vanesa

76

Synthesis and Characteristics of an Aspartame Analogue, L-Asparaginyl L-3-Phenyllactic Acid Methyl Ester  

Microsoft Academic Search

An aspartame analogue, L-asparaginyl L-3-phenyllactic acid methyl ester was synthesized with aspartic acid replaced by asparagine and peptide bond replaced by ester bond. The aspartic acid of aspartame could be replaced by asparagine as reported in the literature. In this analogue, the hydrogen of amide group could still form a hydrogen bond with the oxygen of ester bond and the

Hu TAO; Da-Fu CUI; You-Shang ZHANG

2004-01-01

77

40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Ethylene oxide adduct of fatty acid ester with pentaerythritol...Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with pentaerythritol...identified generically as ethylene oxide adduct of fatty acid ester with...

2010-07-01

78

40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Ethylene oxide adduct of fatty acid ester with pentaerythritol...Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with pentaerythritol...identified generically as ethylene oxide adduct of fatty acid ester with...

2009-07-01

79

40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.  

Code of Federal Regulations, 2012 CFR

...derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to...

2012-07-01

80

40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.  

Code of Federal Regulations, 2010 CFR

...derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to...

2010-07-01

81

Hydrolysis of succinic acid dimethyl ester in rat pancreatic islets.  

PubMed

The hydrolysis of the dimethyl ester of [1,4-14C]succinic acid and/or [2,3-14C]succinic acid was measured in homogenates of rat pancreatic islets, liver, jejunum, brain, BC3H1 mouse myocytes, NG108-19 mouse neuroblastoma x rat glioma hybrid cells, and Caco-2 human colon adenocarcinoma cells. The specific activity of the enzyme was much higher in liver, jejunum, and Caco-2 cells than in the other cell types. The affinity of the enzyme for succinic acid dimethyl ester (SAD) was also much higher in liver than in islet homogenates. In the latter case, both particulate and cytosolic activity were observed upon subcellular fractionation. The activity found in islet homogenates was commensurate with the rate of SAD hydrolysis in intact cells. While the intracellular pool of acidic metabolites generated from SAD remained fairly stable over a 15- to 120-min incubation and was mainly located in the cytosolic compartment, the amount of acidic metabolites released in the extracellular milieu progressively increased with the length of incubation. Such metabolites included both monocarboxylic and dicarboxylic acids, the latter consisting mainly of succinic acid and, to a much lesser extent, of fumaric acid and malic acid. However, at variance with SAD, succinic acid failed to be taken up by intact islets. There was no close parallelism between the specific activity of the SAD esterase and the extent of SAD utilization in distinct cell types. PMID:7582870

Zhang, T M; Sener, A; Malaisse, W J

1995-08-01

82

21 CFR 573.640 - Methyl esters of higher fatty acids.  

Code of Federal Regulations, 2013 CFR

...oleic acid, palmitic acid, palmitoleic acid, and stearic acid, and lesser amounts of the associated acid esters. (b) The food additive meets...respectively; n t and n c are the number of chicks in the respective groups;...

2013-04-01

83

Comparison Of Asymmetric Hydrogenations Of Unsaturated- Carboxylic Acids And -Esters  

PubMed Central

As methodology development matures it can be difficult to discern the most effective ways of performing certain transformations from the rest. This review summarizes the most important contributions leading to asymmetric hydrogenations of simple unsaturated-acid and ester substrates, with the objective of highlighting at least the best types of catalysts for each. Achievements in the area are described and these reveal situations where further efforts should be worthwhile, and ones where more research is only likely to give diminishing returns. In general, our conclusions are that the most useful types of catalysts for unsaturated-acids and -esters tend to be somewhat different, simple substrates have been studied extensively, and the field is poised to address more complex reactions. These could be ones involving alternative, particularly cyclic, structures, chemoselectivity issues, and more complex substrate stereochemistries.

Khumsubdee, Sakunchai; Burgess, Kevin

2013-01-01

84

Use of Functionalized Mesoporous Silicates to Esterify Fatty Acids and Trasesterify Oils.  

National Technical Information Service (NTIS)

The present invention provides a method to prepare a fatty acid lower alkyl esters from a feedstock, such as a vegetable or an animal oil, comprising one or more fatty acid glycerol esters such as mono-, di- or tri-glycerides, and free fatty acids, compri...

D. R. Radu V. S. Yin Lin

2004-01-01

85

Molecular recognition of ?-amino acid esters with arylporphyrin zinc complexes  

Microsoft Academic Search

The recognition ability of 10 arylporphyrin zinc complexes with respect to glycine, a-alanine, and leucine methyl esters in toluene at 20C was studied by spectrophotometric titration. The formation of amino acid-porphyrin associates, depending on the substitution pattern in the macroring, was examined by 1H NMR spectroscopy. The zinc complex with diarylporphyrin having hydroxy groups in the para positions of the

G. M. Mamardashvili; O. E. Storonkina; N. Zh. Mamardashvili

2004-01-01

86

Extraction of nettle leaves using synthetic esters of fatty acids  

Microsoft Academic Search

The extractive power of synthetic esters of higher fatty acids, widely used as emollients in cosmetics, has been studied.\\u000a Three popular emollients isopropyl myristate (IPM), capryl-caprinic triglycerides (CCT) and soybean oil (SO) were used\\u000a to isolate biologically active substances from nettle leaves (Folia urtica). The qualitative compositions of lipophilic biologically active compounds in all extracts have proved to

A. V. Belyakova; V. A. Vainshtein; K. V. Markova; Yu. T. Demchenko; T. H. Chibilyaev

2005-01-01

87

21 CFR 178.3450 - Esters of stearic and palmitic acids.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Esters of stearic and palmitic acids. 178.3450 Section 178.3450 Food and...and Production Aids § 178.3450 Esters of stearic and palmitic acids. The ester stearyl palmitate or...

2009-04-01

88

21 CFR 178.3450 - Esters of stearic and palmitic acids.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Esters of stearic and palmitic acids. 178.3450 Section 178.3450 Food and...and Production Aids § 178.3450 Esters of stearic and palmitic acids. The ester stearyl palmitate or...

2010-01-01

89

21 CFR 178.3450 - Esters of stearic and palmitic acids.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Esters of stearic and palmitic acids. 178.3450 Section 178.3450 Food and...and Production Aids § 178.3450 Esters of stearic and palmitic acids. The ester stearyl palmitate or...

2013-04-01

90

4-Dimenthylaminopyridine or Acid-Catalyzed Synthesis of Esters: A Comparison  

ERIC Educational Resources Information Center

A set of highly atom-economic experiments was developed to highlight the differences between acid- and base-catalyzed ester syntheses and to introduce the principles of atom economy. The hydrochloric acid-catalyzed formation of an ester was compared with the 4-dimethylaminopyradine-catalyzed ester synthesis.

van den Berg, Annemieke W. C.; Hanefeld, Ulf

2006-01-01

91

21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.  

Code of Federal Regulations, 2010 CFR

...monobasic acids consist of polyhydric alcohol esters having number average...Specifications. The polyhydric alcohol esters have the following specifications...1 volume mixture of anhydrous isopropyl alcohol and toluene. The solution is...

2009-04-01

92

Diffuse reflectance Fourier transform infrared spectroscopy of oleic acid adsorption on silicic acid  

Microsoft Academic Search

Diffuse reflectance Fourier transform infrared spectroscopy was used to observe adsorption complexes of oleic acid and isopropanol\\u000a (IPA) on silicic acid in hexane. The spectra provide definite evidence of the molecular nature of the surface interaction.\\u000a In addition, the effect on oleic acid adsorption of modifying the solvent with IPA, which competes for adsorption sites and\\u000a modifies the solvent polarity,

C. Adhikari; A. Proctor; G. D. Blyholder

1994-01-01

93

Characterization of esters of fatty acids and dicarboxylic acids with Guerbet alcohols  

Microsoft Academic Search

Esters of some common fatty acids and diacids with Guerbet alcohols were prepared by p-toluenesulfonic acid-catalyzed esterification. Such materials are of interest in applications such as additives in various\\u000a industrial products. Gas chromatography-mass spectrometry with chemical ionization using methane as ionization gas is an efficient\\u000a characterization method for these Guerbet esters and diesters. Under these conditions, structural features such as

Gerhard Knothe

2001-01-01

94

Hydrolysis kinetics of lead silicate glass in acid solution  

NASA Astrophysics Data System (ADS)

Hydrolysis kinetics of the lead silicate glass (LSG) with 40 mol% PbO in 0.5 N HNO 3 aqueous acid solution was investigated. The surface morphology and the gel layer thickness were studied by scanning electron microscopy (SEM) micrographs. Energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma spectroscopy (ICP) were used to determine the composition of the gel layer and the aqueous solution, respectively. The silicon content of the dissolution products was determined by using weight-loss data and compositions of the gel layer and the solution. The kinetic parameters were determined using the shrinking-core-model (SCM) for rate controlling step. The activation energy obtained for hydrolysis reaction was Qche = 56.07 kJ/mole. The diffusion coefficient of the Pb ions from the gel layer was determined by using its concentration in solution and in LSG. The shrinkage of the sample and the gel layer thickness during dissolution process were determined.

Rahimi, Rafi Ali; Sadrnezhaad, Sayed Khatibuleslam; Raisali, Gholamreza; Hamidi, Amir

2009-06-01

95

Preparation of malvalic and sterculic acid methyl esters from Bombax munguba and Sterculia foetida seed oils  

Microsoft Academic Search

A method has been developed for the preparation of highly pure malvalic (cis-8,9-methyleneheptadec-8-enoic) and sterculic (cis-9,10-methyleneoctadec-9-enoic) acid methyl esters starting from Bombax munguba and Sterculia foetida seed oils. The methyl esters of these oils were prepared by sodium methylate-catalyzed transmethylation followed by cooling\\u000a (6C) the hexane solution of crude methyl esters and separation of insoluble fatty acid methyl esters by

E. Fehling; S. Schnwiese; E. Klein; K. D. Mukherjee; N. Weber

1998-01-01

96

In vitro and in vivo stability of caffeic acid phenethyl ester, a bioactive compound of propolis.  

PubMed

The in vitro biochemical stability of caffeic acid phenethyl ester in rat and human plasma was investigated and compared with the stability of other caffeic acid esters (chlorogenic acid and rosmarinic acid). The incubation of the compounds in rat plasma for up to 6 h showed that caffeic acid phenethyl ester, but not the other compounds, was hydrolyzed, whereas human plasma did not affect the stability of all the assayed compounds. The products in rat plasma were caffeic acid and an unknown compound, which was identified by mass spectrometry as caffeic acid ethyl ester, produced by transesterification in the presence of ethanol used as vehicle for standard compounds. Specific inhibitors of different plasma esterases allowed the identification of a carboxylesterase as the enzyme involved in the metabolism of caffeic acid phenethyl ester. The oral administration in rats of caffeic acid phenethyl ester in the presence of both ethanol and 2-(2-ethoxyethoxy)ethanol gave rise to a dramatic increase of caffeic acid, as well as low levels of caffeic acid phenethyl ester, caffeic acid ethyl ester, and caffeic acid 2-(2-ethoxyethoxy)ethyl ester, in urine collected within 24 h after treatment. These results suggest that caffeic acid phenethyl ester is hydrolyzed also in vivo to caffeic acid as the major metabolite and that its biological activities should be more properly assayed and compared with those of caffeic acid, its bioactive hydrolysis product. Moreover, alcohols should be carefully used in vivo as solvents for caffeic acid phenethyl ester, since they can give rise to new bioactive caffeic acid esters. PMID:17394337

Celli, Nicola; Dragani, Luana K; Murzilli, Stefania; Pagliani, Tommaso; Poggi, Andreina

2007-05-01

97

Electron-impact ionization of benzoic acid, nicotinic acid and their n-butyl esters  

NASA Astrophysics Data System (ADS)

Electron-impact ionization mass spectra, the decay of metastable ions, ionization and appearance energies and bond energies, as dissociation energies, are reported for the title compounds. An ionization energy of 9.47 eV was obtained for benzoic acid, 9.43 eV for benzoic acid n-butyl ester, 9.61 eV for nicotinic acid and 9.97 eV for nicotinic acid n-butyl ester. Molecular ions of both butyl esters show two common main fragmentation pathways: the first process is a McLafferty rearrangement, characterized by the transfer of one H-atom from the aliphatic ester chain, which leads to the ions of either the organic acid or 1-butene. From their appearance energies and known thermodynamic data, gas-phase formation enthalpies () of the parent n-butyl esters are calculated. Values of for benzoic acid n-butyl ester and for nicotinic acid n-butyl ester were obtained. The second process is characterized by the transfer of two H-atoms from the ester chain leading to a protonated form of the corresponding organic acids and C4H7 radicals. Good evidence is provided for the formation of methylallyl radicals. Appearance energies are used to calculate a proton affinity (PA) for benzoic acid. The obtained value of PA = (8.73 0.3) eV, corresponding to a protonation of the carbonyl group, is in close corroboration with published data (PA = 8.51 eV). Activation energies for the intermediate H-transfers were found to be insignificant. This methodic gateway is applied to the system of nicotinic acid and its butyl ester. Adopting the formation of a methylallyl radical, the obtained proton affinity of nicotinic acid, PA = 8.58 eV, is very near to the published data of benzoic acid. An alternative fragmentation mechanism leading to a value of PA [approximate] 9.5 eV (typical for a protonation of the pyridine-nitrogen) is very unlikely. It is concluded that this transfer of two H-atoms from the ester chain is controlled by a charge switching between the carboxylic oxygen atoms which leads to a regiospecific protonation site, in this case to the protonated carbonyl group. This is conform with a B3LYP DFT calculation with a corresponding proton affinity of PA = 8.29 eV.

Opitz, Joachim

2007-08-01

98

Testing the Role of Silicic Acid and Bioorganic Materials in the Formation of Rock Coatings  

SciTech Connect

Silica, amino acids, and DNA were recently discovered in desert varnish. In this work we experimentally test the proposed role of silicic acid and bio-chemicals in the formation of desert varnish and other rock coatings. We have developed a protocol in which hte rocks were treated with a mixture of silicic acid, sugars, amino acids, metals and clays, under the influence of heat and UV light. This protocol reflects the proposed mechanism of hte polymerization of silicic acid with the bioorganic materials, and the laboratory model for the natural conditions under which the desert varnish is formed. Our experiments produced coatings with a hardness and morphology that resemble the nature ones. These results provide a support for the role of silicic acid in the formation of rock coatings. Since the hard silica-based coatings preserve organic compounds in them, they may serve as a biosignature for life, here or possibly Mars.

Kolb, Vera; Philip, Ajish I.; Perry, Randall S.

2004-12-01

99

Testing the role of silicic acid and bioorganic materials in the formation of rock coatings  

NASA Astrophysics Data System (ADS)

Silica, amino acids, and DNA were recently discovered in desert varnish. In this work we experimentally test the proposed role of silicic acid and bio-chemicals in the formation of desert varnish and other rock coatings. We have developed a protocol in which the rocks were treated with a mixture of silicic acid, sugars, amino acids, metals and clays, under the influence of heat and UV light. This protocol reflects the proposed mechanism of the polymerization of silicic acid with the biooganic materials, and the laboratory model for the natural conditions under which the desert varnish is formed. Our experiments produced coatings with a hardness and morphology that resemble the natural ones. These results provide a support for the role of silicic acid in the formation of rock coatings. Since the hard silica-based coatings preserve organic compounds in them, they may serve as a biosignature for life, here or possibly on Mars.

Kolb, Vera M.; Philip, Ajish I.; Perry, Randall S.

2004-11-01

100

Separation and quantitation of free fatty acids and fatty acid methyl esters by reverse phase high pressure liquid chromatography  

Microsoft Academic Search

Reverse phase high pressure liquid chromatogra- phy (HPLC) on octadecylsilyl columns separates mixtures of either free fatty acids or fatty acid methyl esters prepared from mammalian tissue phospholipids. Acetonitrile-water mixtures are used for the elution of esters. Aqueous phosphoric acid is substituted for water for the separation of the free acids. Unsaturated compounds are detected and quantitated by their absorption

Marta I. Aveldano; Mike VanRollins; Lloyd A. Horrocks

101

Estimation of Hydrolysis Rate Constants of Carboxylic Acid Ester and Phosphate Ester Compounds in Aqueous Systems from Molecular Structure by SPARC.  

National Technical Information Service (NTIS)

SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid ester and phosphate ester compounds in aqueous non- aqueous and systems strictly from molecular str...

S. H. Hilal

2006-01-01

102

Assimilation of dietary eicosenoic and erucic acid esters  

Microsoft Academic Search

Summary\\u000a \\u000a \\u000a \\u000a 1.\\u000a \\u000a Eicosenoic acid, fed to rats as methyl ester to the extent of 5% by weight of the diet, was deposited in substantial amount\\u000a in the body fat.\\u000a \\u000a \\u000a \\u000a \\u000a 2.\\u000a \\u000a Erucic acid, fed in the same way, was deposited in considerably lesser amount.\\u000a \\u000a \\u000a \\u000a \\u000a 3.\\u000a \\u000a Neither of these acids appeared to be as readily deposited in body fat as the linoleic

C. Y. Hopkins; Mary J. Chisholm; T. K. Murray; J. A. Campbell

1957-01-01

103

Cinnamyl alcohols and methyl esters of fatty acids from Wedelia prostrata callus cultures  

Microsoft Academic Search

Two methyl esters of fatty acids, namely octadecanoic acid methyl ester (methyl stearate) (1) and hexadecanoic acid methyl ester (methyl palmitate) (2), in addition to four cinnamyl alcohol derivatives, sinapyl alcohol (3), coniferyl alcohol (4), p-coumaryl alcohol (5) and coniferyl alcohol 4-O-glucoside (coniferin) (6), were isolated from callus cultures of Wedelia prostrata. The structure of coniferin was established by spectroscopic

Ahmed M. A. Abd El-Mawla; Salwa F. Farag; Till Beuerle

2011-01-01

104

Neutral Lipid Biosynthesis in Engineered Escherichia coli: Jojoba Oil-Like Wax Esters and Fatty Acid Butyl Esters  

PubMed Central

Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant Escherichia coli strain by coexpression of a fatty alcohol-producing bifunctional acyl-coenzyme A reductase from the jojoba plant and a bacterial wax ester synthase from Acinetobacter baylyi strain ADP1, catalyzing the esterification of fatty alcohols and coenzyme A thioesters of fatty acids. In the presence of oleate, jojoba oil-like wax esters such as palmityl oleate, palmityl palmitoleate, and oleyl oleate were produced, amounting to up to ca. 1% of the cellular dry weight. In addition to wax esters, fatty acid butyl esters were unexpectedly observed in the presence of oleate. The latter could be attributed to solvent residues of 1-butanol present in the medium component, Bacto tryptone. Neutral lipids produced in recombinant E. coli were accumulated as intracytoplasmic inclusions, demonstrating that the formation and structural integrity of bacterial lipid bodies do not require specific structural proteins. This is the first report on substantial biosynthesis and accumulation of neutral lipids in E. coli, which might open new perspectives for the biotechnological production of cheap jojoba oil equivalents from inexpensive resources employing recombinant microorganisms.

Kalscheuer, Rainer; Stoveken, Tim; Luftmann, Heinrich; Malkus, Ursula; Reichelt, Rudolf; Steinbuchel, Alexander

2006-01-01

105

Neutral lipid biosynthesis in engineered Escherichia coli: jojoba oil-like wax esters and fatty acid butyl esters.  

PubMed

Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant Escherichia coli strain by coexpression of a fatty alcohol-producing bifunctional acyl-coenzyme A reductase from the jojoba plant and a bacterial wax ester synthase from Acinetobacter baylyi strain ADP1, catalyzing the esterification of fatty alcohols and coenzyme A thioesters of fatty acids. In the presence of oleate, jojoba oil-like wax esters such as palmityl oleate, palmityl palmitoleate, and oleyl oleate were produced, amounting to up to ca. 1% of the cellular dry weight. In addition to wax esters, fatty acid butyl esters were unexpectedly observed in the presence of oleate. The latter could be attributed to solvent residues of 1-butanol present in the medium component, Bacto tryptone. Neutral lipids produced in recombinant E. coli were accumulated as intracytoplasmic inclusions, demonstrating that the formation and structural integrity of bacterial lipid bodies do not require specific structural proteins. This is the first report on substantial biosynthesis and accumulation of neutral lipids in E. coli, which might open new perspectives for the biotechnological production of cheap jojoba oil equivalents from inexpensive resources employing recombinant microorganisms. PMID:16461689

Kalscheuer, Rainer; Stveken, Tim; Luftmann, Heinrich; Malkus, Ursula; Reichelt, Rudolf; Steinbchel, Alexander

2006-02-01

106

Materials Science Cements Containing Syringic Acid Esters- o-Ethoxybenzoic Acid and Zinc Oxide  

Microsoft Academic Search

Fissure caries is reduced when syringic acid is incorporated into a cariogenic diet of rats. It was therefore of interest to synthesize n-hexyl and 2-ethylhexyl syringate and to evaluate the properties of cements with these compounds as ingredients. Liquids containing the esters dissolved in o-ethoxybenzoic acid (EBA) - when mixed with powders made up from zinc oxide, aluminum oxide, and

G. M. Brauer; J. W. Stansbury

1984-01-01

107

Preparation and physical properties of some C 18 unsaturated fatty esters containing L -amino acid residues and methyl esters of N -stearoylamino acids  

Microsoft Academic Search

A series of five C18 unsaturated fatty esters (15) containing anL-amino acid residue (glycine, alanine, valine, leucine, phenylalanine) was prepared from methyl 12-amino-9-cis-octadecenoate and five methylN-stearoyl-amino acid ester derivatives (610) from stearoyl chloride and the sameL-amino acids. The infrared analysis of compounds 15 showed characteristic absorption bands at 3300 and 1665 cm?1 for the amino and amido functions, while the

Marcel S. F. Lie Ken Jie; H. B. Lao; David W. Y. Leung

1990-01-01

108

21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.  

Code of Federal Regulations, 2013 CFR

...propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene glycol may be...specifications: Water insoluble combined lactic acid, 14-18 percent; and acid number, 12 maximum. (c) It is used in amounts...

2013-04-01

109

21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.  

Code of Federal Regulations, 2010 CFR

...propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene glycol may be...specifications: Water insoluble combined lactic acid, 14-18 percent; and acid number, 12 maximum. (c) It is used in amounts...

2010-01-01

110

21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.  

Code of Federal Regulations, 2010 CFR

...propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene glycol may be...specifications: Water insoluble combined lactic acid, 14-18 percent; and acid number, 12 maximum. (c) It is used in amounts...

2009-04-01

111

Mass spectrometry of polycyclic tetracarboxylic ('ARN') acids and tetramethyl esters.  

PubMed

Polycyclic C(80) tetracarboxylic (so-called 'ARN') acids are found as calcium salts in deposits which form in certain oilfield pipelines and equipment. Characterisation of these acids is important for improving the prediction and hence avoidance or minimisation of oilfield deposition problems. Although several of the acids have been isolated and characterised (as regioisomeric mixtures) by nuclear magnetic resonance spectroscopy, mass spectrometric methods are likely to be much more useful for the routine analysis of oils and deposits containing the acids. A publication summarising the mass spectra of the purified acids and major derivatives might thus be a very useful source of reference for scientists and technologists studying these unusual compounds. We now report the characterisation of several of the purified acids and of the tetramethyl esters by electrospray ionisation mass spectrometry (ESI-MS) in both positive ion and negative ion modes, by multistage ESI-MS with a suggested rationalisation of the ions produced, by positive ion atmospheric solids analysis probe (ASAP) atmospheric pressure chemical ionisation (APCI), and by positive ion electron ionisation (EI)-MS. Tentative identifications of C(80) acyclic, mono-, bi- and tricylic tetraacids and the ?(13)C isotope values of a mixture of the semi-pure acids determined by MS are also reported for the first time. PMID:20941768

Sutton, Paul A; Smith, Benjamin E; Rowland, Steven J

2010-11-15

112

Calculation of 29Si NMR shifts of silicate complexes with carbohydrates, amino acids, and muhicarboxylic acids: potential role in biological silica utilization  

NASA Astrophysics Data System (ADS)

The existence of ether or ester-like complexes of silicate with organic compounds has long been debated in the literature on biological utilization of silicon. Comparison of theoretically calculated 29Si NMR chemical shifts for such complexes with experimentally measured values in biological systems could provide a diagnostic tool for identifying which, if any of these molecules exist under physiological conditions. Results are presented here for ab initio molecular orbital calculations of 29Si NMR shifts and formation energies of silicate complexes with polyalcohols, sugar-acids, pyranose sugars, amino acids and multicarboxylic acids. The effects of functional group and molecular structure including ligand size, denticity, ring size, silicon polymerization and coordination number on calculated 29Si shifts were considered. The potential role of such compounds in biological silica utilization pathways is discussed. 29Si NMR shifts and energies were calculated at the HF/6-311+G(2d,p)//HF/6-31G* level. The main result is that only five-membered rings containing penta- and hexa-coordinated Si can explain experimentally observed resonances at -101 and -141 ppm. Further, the heptet observed in 1H- 29Si coupled spectra can only be explained by structures where Si bonds to oxygens atoms in H-C-O-Si linkages with six symmetrically equivalent H atoms. While compounds containing quadra-coordinated silicon may exist in intracellular silicon storage pools within diatoms, calculated reaction energies suggest that the organism has no thermodynamic advantage in taking up extracellular organ-silicate compounds, instead of silicic acid, from the ambient aqueous environment. Hyper-coordinated complexes are deemed unlikely for transport and storage, though they may exist as transient reactive intermediates or activated complexes during enzymatically- catalyzed silica polymerization, as known previously from sol-gel silica synthesis studies.

Sahai, Nita

2004-01-01

113

Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca  

PubMed Central

Summary The volatiles released by Micromonospora aurantiaca were collected by means of a closed-loop stripping apparatus (CLSA) and analysed by GCMS. The headspace extracts contained more than 90 compounds from different classes. Fatty acid methyl esters (FAMEs) comprised the major compound class including saturated unbranched, monomethyl and dimethyl branched FAMEs in diverse structural variants: Unbranched, ?-branched, ?-branched, (??1)-branched, (??2)-branched, ?- and (??1)-branched, ?- and (??1)-branched, ?- and (??2)-branched, and ?- and (??3)-branched FAMEs. FAMEs of the last three types have not been described from natural sources before. The structures for all FAMEs have been suggested based on their mass spectra and on a retention index increment system and verified by the synthesis of key reference compounds. In addition, the structures of two FAMEs, methyl 4,8-dimethyldodecanoate and the ethyl-branched compound methyl 8-ethyl-4-methyldodecanoate were deduced from their mass spectra. Feeding experiments with isotopically labelled [2H10]leucine, [2H10]isoleucine, [2H8]valine, [2H5]sodium propionate, and [methyl-2H3]methionine demonstrated that the responsible fatty acid synthase (FAS) can use different branched and unbranched starter units and is able to incorporate methylmalonyl-CoA elongation units for internal methyl branches in various chain positions, while the methyl ester function is derived from S-adenosyl methionine (SAM).

Bruns, Hilke; Riclea, Ramona

2011-01-01

114

The uptake of silicic acid by rat liver mitochondria.  

PubMed Central

1. To gain insight into a putative role for mitochondria in silicon metabolism, mitochondrial uptake (by which it is meant the removal from the medium) of silicic acid [Si(OH)4] was studied under conditions minimizing SI(OH)4 polymerization. 2. Measurements of mitochondrial respiration and swelling indicated indirectly a significant uptake of Si(OH)4 as a weak acid, but this was not confirmed when 31Si(OH)4 was used as a tracer. 31Si(OH)4 occupied a mitochondrial volume similar to that of 3H2O and was relatively unaffected by mitochondrial energy status and by the pH gradient across the mitochondrial inner membrane. 3. Uptake was directly proportional to Si(OH)4 concentration in the range 0-3 mM. 4. The uptake consisted of two components: under all conditions examined, the greater quantity, amounting to 1-2nmol of Si(OH)4/mg of mitochondrial protein, was bound, a major portion of it external to the inner membrane, with the lesser quantity free within the matrix space. 5. Equilibration of 31Si(OH)4 between medium and matrix was a slow process, having a half-time of approx. 10 min at 22 degrees C. 6. Mersalyl and N-ethylmaleimide inhibited the uptake by preferentially lowering the amount of Si(OH)4 bound. Their action was somewhat variable, depending on the precise nature of the suspending medium, and suggesting that the bound material may represent polymerized forms of Si(OH)4. 7. It is concluded that Si(OH)4 may penetrate the mitochondrial inner membrane by a simple diffusion mechanism.

Johnson, R N; Volcani, B E

1978-01-01

115

Fractionation of fats, oils, and waxes on thin layers of silicic acid  

Microsoft Academic Search

SummaryAdsorption chromatography on thin layers of silicic acid or alumina provides a new and highly efficient analytical tool for\\u000a the rapid separation of lipids according to classes of compounds.

Helmut K. Mangold; Donald C. Malins

1960-01-01

116

Synthesis, Evaluation of Anticancer Activity and QSAR Study of Heterocyclic Esters of Caffeic Acid  

PubMed Central

Caffeic acid phenethyl ester (CAPE) suppresses the growth of transformed cells such as human breast cancer cells, hepatocarcinoma , myeloid leukemia, colorectal cancer cells, fibrosarcoma, glioma and melanoma. A group of heterocyclic esters of caffeic acid was synthesized using Mitsunobu reaction and the esters were subjected to further structural modification by electrooxidation of the catechol ring of caffeic acid esters in the presence of sodium benzenesulfinate and sodium toluensulfinate as nucleophiles. Both heterocyclic esters of caffeic acid and their arylsulfonyl derivatives were evaluated for their cytotoxic activity against HeLa, SK-OV-3, and HT-29 cancer cell lines. HeLa cells showed the highest sensitivity to the compounds and heterocyclic esters with no substituent on catechol ring showed better activity compared to their substituted counterparts. QSAR studies reemphasized the importance of molecular shape of the compounds for their cytotoxic activity.

Hajmohamad Ebrahim Ketabforoosh, Shima; Amini, Mohsen; Vosooghi, Mohsen; Shafiee, Abbas; Azizi, Ebrahim; Kobarfard, Farzad

2013-01-01

117

Fundamental Study on Temperature Dependence of Deposition Rate of Silicic Acid - 13270  

SciTech Connect

The dynamic behavior of the silicic acid is one of the key factors to estimate the condition of the repository system after the backfill. This study experimentally examined the temperature dependence of dynamic behavior of supersaturated silicic acid in the co-presence of solid phase, considering Na ions around the repository, and evaluated the deposition rate constant, k, of silicic acid by using the first-order reaction equation considering the specific surface area. The values of k were in the range of 1.0x10{sup -11} to 1.0x10{sup -9} m/s in the temperature range of 288 K to 323 K. The deposition rate became larger with increments of temperature under the Na ion free condition. Besides, in the case of Na ions 0.6 M, colloidal silicic acid decreased dramatically at a certain time. This means that the diameter of the colloidal silicic acid became larger than the pore size of filter (0.45 ?m) due to bridging of colloidal silicic acid. Furthermore, this study estimated the range of altering area and the aperture of flow-path in various value of k corresponding to temperature by using advection-dispersion model. The concentration in the flow-path became lower with increments of temperature, and when the value of k is larger than 1.0x10{sup -11} m/s, the deposition range of supersaturated silicic acid was estimated to be less than 20 m around the repository. In addition, the deposition of supersaturated silicic acid led the decrement of flow-path aperture, which was remarkable under the condition of relatively high temperature. Such a clogging in flow paths is expected as a retardation effect of radionuclides. (authors)

Shinmura, Hayata; Niibori, Yuichi; Mimura, Hitoshi [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, 6-6-01-2 Aobayama, Aoba-ku, Sendai 980-8579 (Japan)] [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, 6-6-01-2 Aobayama, Aoba-ku, Sendai 980-8579 (Japan)

2013-07-01

118

Carboxypeptidase Y catalyzed peptide synthesis using amino acid alkyl esters as amine components  

Microsoft Academic Search

Carboxypeptidase Y catalyzed transacylation reactions between N-protected amino acid methyl esters or peptide methyl esters\\u000a as initial acyl components and methyl, ethyl, isopropyl or tert.-butyl esters of different ?-amino acids as amine components\\u000a are described. The yield of peptide bond formation and the extent of oligomerization of the amine components both depend on\\u000a the nature of their side chain as

Fred Widmer; Klaus Breddam; Jack T. Johansen

1980-01-01

119

[Synthesis of methyl ester of aliphatic acid under irradiation of ultraviolet and mass spectra (MS) analysis].  

PubMed

A new method was introduced here to prepare methyl ester of aliphatic acid under irradiation of ultraviolet. Analysis was performed for the MS spectra of 19 products, by which Mclafferty rearrangements were discussed of methyl ester of aliphatic acid with two kinds of gamma-H in details. The regularity of Mclafferty rearrangement was established for the same kind of methyl ester with the increase of the carbon chain. PMID:15822273

Yin, J; Gao, D; Zheng, X; Ma, Y

1999-10-01

120

Direct Determination of MCPD Fatty Acid Esters and Glycidyl Fatty Acid Esters in Vegetable Oils by LC-TOFMS  

PubMed Central

Analysis of MCPD esters and glycidyl esters in vegetable oils using the indirect method proposed by the DGF gave inconsistent results when salting out conditions were varied. Subsequent investigation showed that the method was destroying and reforming MCPD during the analysis. An LC time of flight MS method was developed for direct analysis of both MCPD esters and glycidyl esters in vegetable oils. The results of the LCTOFMS method were compared with the DGF method. The DGF method consistently gave results that were greater than the LCTOFMS method. The levels of MCPD esters and glycidyl esters found in a variety of vegetable oils are reported. MCPD monoesters were not found in any oil samples. MCPD diesters were found only in samples containing palm oil, and were not present in all palm oil samples. Glycidyl esters were found in a wide variety of oils. Some processing conditions that influence the concentration of MCPD esters and glycidyl esters are discussed.

Haines, Troy D.; Adlaf, Kevin J.; Pierceall, Robert M.; Lee, Inmok; Venkitasubramanian, Padmesh

2010-01-01

121

Consideration on the relationship between dielectric breakdown voltage and water content in fatty acid esters  

Microsoft Academic Search

Recently, fatty acid esters synthesized from the natural oil obtained from plants have attracted much attention as an insulating oil from the viewpoint of environmental problems, fluidity, and greater resistance to dielectric breakdown than conventional mineral oil. In the present study, to clarify the reason for the superior moisture tolerance of fatty acid esters, the inter- and intramolecular movements of

T. Suzuki; R. Oba; A. Kanetani; T. Kano; T. Tamura; M. Kato; S. Watanabe; Y. Kasahara; M. Iwahashi

2011-01-01

122

Preparation of fatty acid methyl esters and dimethylacetals from lipids with boron fluoride-methanol  

Microsoft Academic Search

SUMMARY Fatty acid methyl esters and dimethylacetals suitable for gas chromatographic analysis were prepared by treatment of lipids with boron fluoride-methanol (140 g BFI per liter of methanol). This reagent is stable and easy to handle. Reaction conditions were investigated for triglycerides, di- glycerides, monoglycerides, free fatty acids, sterol esters, phos- phatidyl ethanolamines, phosphatidyl serines, phosphatidyl 'cholines, monophosphoinositides, monogalactosyl glycerides,

WILLIAM R. MORRISON; LLOYD M. SMITH

123

Chiral Resolution of Benzophenone Imine Derivatives of Amino Acid Esters on Chiral Stationary Phases  

Microsoft Academic Search

A convenient way of resolving the enantiomers of amino acid esters after their derivatization using benzophenone imine is described. The enantiomers of benzophenone Schiff base derivatives of various amino acid ethyl esters are readily separated on three commercially available chiral stationary phases (CSPs). Among them, CSPs 2 and 3 afford generally the base-line enantioresolution for the analytes studied. From understanding

Wonjae Lee

1997-01-01

124

Complexes of polyadenylic acid and the methyl esters of amino acids  

NASA Technical Reports Server (NTRS)

A study of amino acid methyl esters binding to polyadenylic acid supports the theory that the genetic code originated through weak but selective affinities between amino acids and nucleotides. NMR, insoluble complex analysis, and ultraviolet spectroscopy are used to illustrate a correlation between the hydrophybicities of A amino acids and their binding constants, which, beginning with the largest, are in the order of Phe (having nominally a hydrophobic AAA anticodon), Ile, Leu, Val and Gly (having a hydrophilic anticodon with no A). In general, the binding constants are twice the values by Reuben and Polk (1980) for monomeric AMP, which suggests that polymer amino acids are interacting with only one base. No real differences are found betwen poly A binding for free Phe, Phe methyl ester or Phe amide, except that the amide value is slightly lower.

Khaled, M. A.; Mulins, D. W., Jr.; Swindle, M.; Lacey, J. C., Jr.

1983-01-01

125

Carotenoids and their fatty-acid esters in banana peel.  

PubMed

In relation to banana ripening, banana peel was examined for carotenoid pigments by a combination of alumina column chromatography and high-performance liquid chromatography (HPLC). Carotenoids and their fatty-acid esters were first separated by an alumina column into five fractions, of which each was further subfractionated by HPLC with different kinds of solvent. The carotenoid content of the banana peel was in the range of 3-4 micrograms per gram as lutein equivalent. The ingredients of the carotenoids were ascertained to consist of lutein, beta-carotene, alpha-carotene, violaxanthin, auroxanthin, neoxanthin, isolutein, beta-cryptoxanthin and alpha-cryptoxanthin. Most of the oxygenated carotenoids were found to occur in the esterified form, mainly with myristate, and to a lesser extent with laurate, palmitate or caprate. PMID:9089481

Subagio, A; Morita, N; Sawada, S

1996-12-01

126

Fumaric acid esters in psoriasis and multiple sclerosis.  

PubMed

Fumaric acid esters (FAEs) are effective in patients with moderate to severe psoriasis. Recent studies also report the efficacy of one FAE component, dimethylfumarate, in relapsing forms of multiple sclerosis (MS). We describe the case of a patient with MS who developed severe plaque psoriasis during interferon-?-1a treatment for MS. The psoriasis was unresponsive to usual topical treatments and phototherapy. The patient was started on FAE 720mg daily, with complete remission of the psoriatic lesions and neurological stabilization at follow-up at 24months. Our case suggests that FAEs could represent a therapeutic option for patients with MS who develop plaque psoriasis following exposure to immune-modulating agents. PMID:24779791

Zecca, C; Caporro, M; Adami, M; Mainetti, C; Gobbi, C

2014-06-01

127

Effects of phthalic acid esters on the liver and thyroid  

SciTech Connect

The effects, over periods from 3 days to 9 months of administration, of diets containing di-2-ethylhexyl phthalate are very similar to those observed in rats administered diets containing hypolipidemic drugs such as clofibrate. Changes occur in a characteristic order commencing with alterations in the distribution of lipid within the liver, quickly followed by proliferation of hepatic peroxisomes and induction of the specialized P-450 isoenzyme(s) catalyzing omega oxidation of fatty acids. There follows a phase of mild liver damage indicated by changes in incorporation of /sup 3/H-thymidine into DNA, by induction of glucose-6-phosphatase activity and a loss of glycogen, eventually leading to the formation of enlarged lysosomes through autophagy and the accumulation of lipofuscin. Associated changes are found in the kidney and thyroid. The renal changes are limited to the proximal convoluted tubules and are generally similar to changes found in the liver. The effects on the thyroid are more marked. Although the levels of thyroxine in plasma fall to about half normal values, serum triiodothyronine remains close to normal values while the appearance of the thyroid varies, very marked hyperactivity being noted 7 days after commencement of treatment, this is less marked at 14 days, but even after 9 months treatment there is clear cut evidence for hyperactivity with colloid changes which indicate this has persisted for some time. The short-term in vivo hepatic effects of the three phthalate esters can be reproduced in hepatocytes in tissue culture. All three phthalate esters, as well as clofibrate, have early marked effects on the metabolism of fatty acids in isolated hepatocytes. A hypothesis is presented to explain the progress from these initial metabolic effects to the final formation of liver tumors.

Hinton, R.H.; Mitchell, F.E.; Mann, A.; Chescoe, D.; Price, S.C.; Nunn, A.; Grasso, P.; Bridges, J.W.

1986-12-01

128

40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.  

Code of Federal Regulations, 2010 CFR

(1) The chemical substances identified as fatty acid polyamine condensate, phosphate ester salts (PMNs P-90-1984 and P-90-1985) are subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this section. (2) The significant new uses...

2010-07-01

129

[Development of the determination methods of fatty acid esters of chloropropanediols in fat-rich foods].  

PubMed

Fatty acid esters of chloropropanediols are a kinds of newly emerged food contaminants, especially 3-monochloropropane-1,2-diol (3-MCPD) esters that have been detected in many foodstuffs such as infant formula and edible oils at relatively high levels. Based on the Tolerable Dose Intake (TDI) of 3-MCPD, the intake of 3-MCPD from 3-MCPD esters may cause the health risk to human beings. The researches for the analysis of 3-MCPD esters have been carried out in some institutes abroad, but there were only a few in China. This paper reviews the methods for the determination of 3-MCPD esters in fat-rich foods, including the extraction, hydrolysis, the derivatization of 3-MCPD esters, the total amount of 3-MCPD esters and the amounts of monoesters and diesters of 3-MCPD. PMID:23697171

Yan, Xiaobo; Wu, Shaoming; Li, Nan; L, Huadong; Fu, Wusheng

2013-02-01

130

Transformations of Glycyrrhizic Acid: XV. Synthesis of Triterpene Saponins with Monosaccharide Residues Attached through Ester Bonds  

Microsoft Academic Search

Triterpene saponins, glycoside analogues of glycyrrhizic acid with a modified carbohydrate chain containing monosaccharide residues attached through ester bonds, were synthesized. To this end, peracetylated glycyrrhizic acid or its 30-methyl ester were glycosylated by 2,3,4,6-tetra-O-acetyl-a-D-gluco- or -a-D-galactopyranosyl bromide in dichloroethane in the presence of Ag2CO3. Glycerrhetinic acid saponin with D-Galp residues exhibited a higher antiulcer activity than glycyrrhizic acid in

R. M. Kondratenko; L. A. Baltina; S. R. Mustafina; E. V. Vasil'eva; A. F. Ismagilova; N. G. Vasil'eva; G. A. Tolstikov

2003-01-01

131

Synthesis and properties of fatty acid starch esters.  

PubMed

Being completely bio-based, fatty acid starch esters (FASEs) are attractive materials that represent an alternative to crude oil-based plastics. In this study, two synthesis methods were compared in terms of their efficiency, toxicity and, especially, product solubility with starch laurate (C12) as model compound. Laurates (DS>2) were obtained through transesterification of fatty acid vinylesters in DMSO or reaction with fatty acid chlorides in pyridine. The latter lead to higher DS-values in a shorter reaction time. But due to the much better solubility of the products compared to lauroyl chloride esterified ones, vinylester-transesterification was preferred to optimize reaction parameters, where reaction time could be shortened to 2h. FASEs C6-C18 were also successfully prepared via transesterification. To determine the DS of the resulting starch laurates, the efficient ATR-IR method was compared with common methods (elementary analysis, (1)H NMR). Molar masses (Mw) of the highly soluble starch laurates were analyzed using SEC-MALLS (THF). High recovery rates (>80%) attest to the outstanding solubility of products obtained through transesterification, caused by a slight disintegration during synthesis. Particle size distributions (DLS) demonstrated stable dissolutions in CHCl3 of vinyl laurate esterified - contrary to lauroyl chloride esterified starch. For all highly soluble FASEs (C6-C18), formation of concentrated solutions (10 wt%) is feasible. PMID:23987337

Winkler, Henning; Vorwerg, Waltraud; Wetzel, Hendrik

2013-10-15

132

Polymerization of Vinyl Ether by Use of Yttrium Silicate Gel as Solid Acid  

Microsoft Academic Search

The gel of yttrium silicate was utilized as a solid catalyst for the polymerization of vinyl ethers. Several silicate gels showing the different element ratios of silicon and yttrium were prepared by the co-gelation of sodium metasilicate and yttrium(III) chloride from an acidic aqueous solution through neutralization by an aqueous ammonia. The polymerizations of ethyl vinyl ether and n-butyl vinyl

Osamu Moriya; Toshio Sugizaki; Atsuko Kamejima; Ken Iwakura; Takeo Kumon; Toshifumi Kageyama

2006-01-01

133

75 FR 70254 - Typographical Error in Summary Notice of Filing in Docket for Polymerized Fatty Acid Esters With...  

Federal Register 2010, 2011, 2012, 2013

...Register Volume 75, Number 221 (Wednesday...Polymerized Fatty Acid Esters With Aminoalcohol...polymerized fatty acid esters with aminoalcohol...placed in docket ID number: EPA-HQ-OPP-2010-0275...Facility telephone number is (703) 305-5805...polymerized fatty acid esters with...

2010-11-17

134

Asymmetric Synthesis of Diverse Glycolic Acid Scaffolds via Dynamic Kinetic Resolution of ?-Keto Esters  

PubMed Central

The dynamic kinetic resolution of ?-keto esters via asymmetric transfer hydrogenation has been developed as a technique for the highly stereoselective construction of structurally diverse ?-substituted-?-hydroxy carboxylic acid derivatives. Through the development of a privileged m-terphenylsulfonamide for (arene)RuCl(monosulfonamide) complexes with a high affinity for selective ?-keto ester reduction, excellent levels of chemo-, diastereo-, and enantiocontrol can be realized in the reduction of ?-aryl- and ?-chloro-?-keto esters.

Steward, Kimberly M.; Corbett, Michael T.; Goodman, C. Guy; Johnson, Jeffrey S.

2012-01-01

135

The content and composition of sterols and sterol esters in low erucic acid rapeseed ( Brassica napus )  

Microsoft Academic Search

The low temperature crystallization technique for the enrichment of minor components, such as sterols and sterol esters,\\u000a from vegetable oils was applied to low erucic acid rapeseed oils. The recovery of free sterols and sterol esters was estimated\\u000a by use of14C-cholesterol and14C-cholesterol oleate. 80% of the free sterols and 45% of the sterol esters were recovered in the liquid fraction,

Anna Johansson; Lars-ke Appelqvist

1978-01-01

136

Summary of the technology for the manufacture of higher alpha-sulfo fatty acid esters  

Microsoft Academic Search

Interest in ?-sulfonated higher molecular weight (up to C20) fatty esters has increased in recent years in the surfactant industry due to the advent of economical sulfonation processes\\u000a and methyl esters of fatty acids. In this paper, the authors present a review of the chemistry of the sulfonation of fatty\\u000a esters and the two-step mechanism leading to ?-sulfonation. Laboratory and

B. L. Kapur; J. M. Solomon; B. R. Bluestein

1978-01-01

137

Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of ?-Tocopherol: The Hydroperoxide Pathway  

Microsoft Academic Search

Autoxidation of conjugated linoleic acid (CLA) methyl ester follows at least partly Farmers hydroperoxide theory. A mechanism\\u000a for this hydroperoxide pathway has been proposed based on autoxidation of 9-cis,11-trans-CLA methyl ester. This investigation aims at confirming and further clarifying the mechanism by analyzing the hydroperoxides\\u000a produced from 10-trans,12-cis-CLA methyl ester and by theoretical calculations. Five methyl hydroxyoctadecadienoates were isolated by

Taina I. Pajunen; Mikael P. Johansson; Tapio Hase; Anu Hopia

2008-01-01

138

21 CFR 573.637 - Methyl esters of conjugated linoleic acid (cis-9, trans-11 and trans-10, cis-12-octadecadienoic...  

Code of Federal Regulations, 2010 CFR

...percent. The additive shall contain not less than 35 percent of other fatty acid esters composed of oleic acid, palmitic acid, stearic acid, linoleic acid, and other associated acid esters. (b) The additive is used or intended for use...

2010-04-01

139

21 CFR 573.637 - Methyl esters of conjugated linoleic acid (cis-9, trans-11 and trans-10, cis-12-octadecadienoic...  

Code of Federal Regulations, 2010 CFR

...percent. The additive shall contain not less than 35 percent of other fatty acid esters composed of oleic acid, palmitic acid, stearic acid, linoleic acid, and other associated acid esters. (b) The additive is used or intended for use...

2009-04-01

140

21 CFR 573.637 - Methyl esters of conjugated linoleic acid (cis-9, trans-11 and trans-10, cis-12-octadecadienoic...  

Code of Federal Regulations, 2013 CFR

...percent. The additive shall contain not less than 35 percent of other fatty acid esters composed of oleic acid, palmitic acid, stearic acid, linoleic acid, and other associated acid esters. (b) The additive is used or intended for use...

2013-04-01

141

Relative oral bioavailability of glycidol from glycidyl fatty acid esters in rats.  

PubMed

In order to quantify the relative bioavailability of glycidol from glycidyl fatty acid esters in vivo, glycidyl palmitoyl ester and glycidol were orally applied to rats in equimolar doses. The time courses of the amounts of glycidol binding to hemoglobin as well as the excretion of 2,3-dihydroxypropyl mercapturic acids were determined. The results indicate that glycidol is released from the glycidyl ester by hydrolysis and rapidly distributed in the organism. In relation to glycidol, there was only a small timely delay in the binding to hemoglobin for the glycidol moiety released from the ester which may be certainly attributed to enzymatic hydrolysis. In both cases, however, an analogous plateau was observed representing similar amounts of hemoglobin binding. With regard to the urinary excretion of mercapturic acids, also similar amounts of dihydroxypropyl mercapturic acids could be detected. In an ADME test using a virtual double tag (H, ?C) of glycidyl palmitoyl ester, a diverging isotope distribution was detected. The kinetics of the ?C-activity reflected the kinetics of free glycidol released after hydrolysis of the palmitoyl ester. In view of this experimental data obtained in rats, it is at present justified for the purpose of risk assessment to assume complete hydrolysis of the glycidyl ester in the gastrointestinal tract. Therefore, assessment of human exposure to glycidyl fatty acid ester should be regarded as an exposure to the same molar quantity of glycidol. PMID:23649841

Appel, Klaus E; Abraham, Klaus; Berger-Preiss, Edith; Hansen, Tanja; Apel, Elisabeth; Schuchardt, Sven; Vogt, Carla; Bakhiya, Nadiya; Creutzenberg, Otto; Lampen, Alfonso

2013-09-01

142

Antioxidant activity of propolis: role of caffeic acid phenethyl ester and galangin  

Microsoft Academic Search

Propolis, a natural product produced by the honeybee, has been used for thousands of years in folk medicine for several purposes. The extract contains amino acids, phenolic acids, phenolic acid esters, flavonoids, cinnamic acid, terpenes and caffeic acid. It possesses several biological activities such as antiinflammatory, immunostimulatory, antiviral and antibacterial. The exact mode of physiological or biochemical mechanisms responsible for

A Russo; R Longo; A Vanella

2002-01-01

143

Applications of propargyl esters of amino acids in solution-phase Peptide synthesis.  

PubMed

Propargyl esters are employed as effective protecting groups for the carboxyl group during solution-phase peptide synthesis. The propargyl ester groups can be introduced onto free amino acids by treating them with propargyl alcohol saturated with HCl. The reaction between propargyl groups and tetrathiomolybdate is exploited to deblock the propargyl esters. The removal of the propargyl group with the neutral reagent tetrathiomolybdate ensures that most of the other protecting groups used in peptide synthesis are untouched. Both acid labile and base labile protecting groups can be removed in the presence of a propargyl ester. Amino acids protected as propargyl esters are employed to synthesize di- to tetrapeptides in solution-phase demonstrating the possible synthetic utilities of the methodology. The methodology described here could be a valuable addition to currently available strategies for peptide synthesis. PMID:21760822

Ramapanicker, Ramesh; Gupta, Rohit; Megha, Rajendran; Chandrasekaran, Srinivasan

2011-01-01

144

A rapid low temperature method for preparation of methyl esters of fatty acids  

Microsoft Academic Search

A rapid method for preparation of methyl esters of fatty acids in lipids has been accomplished by forming the sulfuric acid\\u000a complex of the lipid in ethyl ether at the temp of a dry ice-acetone bath. Decomposition of the complex with methanol results\\u000a in direct formation of methyl esters of the fatty acids. A comparison was made of gas liquid

Gertrude W. McGinnis; L. R. Dugan

1965-01-01

145

Water chemical ionization mass spectrometry of aldehydes, ketones esters, and carboxylic acids  

Microsoft Academic Search

Chemical ionization mass spectrometry (CI) of aliphatic and aromatic carbonyl compounds using water as the reagent gas provides intense pseudomolecular ions and class-specific fragmentation patterns that can be used to identify aliphatic aldehydes, ketones, carboxylic acids, and esters. The length of ester acyl and alkyl groups can easily be determined on the basis of loss of alcohols from the protonated

Steven B. Hawthorne; David J. Miller

1986-01-01

146

A convenient enantioselective decarboxylative aldol reaction to access chiral ?-hydroxy esters using ?-keto acids  

PubMed Central

Summary We show a convenient decarboxylative aldol process using a scandium catalyst and a PYBOX ligand to generate a series of highly functionalized chiral ?-hydroxy esters. The protocol tolerates a broad range of ?-keto acids with inactivated aromatic and aliphatic ?-keto esters. The possible mechanism is rationalized.

Duan, Zhiqiang; Han, Jianlin; Qian, Ping; Zhang, Zirui; Pan, Yi

2014-01-01

147

A convenient enantioselective decarboxylative aldol reaction to access chiral ?-hydroxy esters using ?-keto acids.  

PubMed

We show a convenient decarboxylative aldol process using a scandium catalyst and a PYBOX ligand to generate a series of highly functionalized chiral ?-hydroxy esters. The protocol tolerates a broad range of ?-keto acids with inactivated aromatic and aliphatic ?-keto esters. The possible mechanism is rationalized. PMID:24991246

Duan, Zhiqiang; Han, Jianlin; Qian, Ping; Zhang, Zirui; Wang, Yi; Pan, Yi

2014-01-01

148

Effects of phthalic acid esters on the liver and thyroid.  

PubMed Central

The effects, over periods from 3 days to 9 months of administration, of diets containing di-2-ethylhexyl phthalate are very similar to those observed in rats administered diets containing hypolipidemic drugs such as clofibrate. Changes occur in a characteristic order commencing with alterations in the distribution of lipid within the liver, quickly followed by proliferation of hepatic peroxisomes and induction of the specialized P-450 isoenzyme(s) catalyzing omega oxidation of fatty acids. There follows a phase of mild liver damage indicated by induction of glucose-6-phosphatase activity and a loss of glycogen, eventually leading to the formation of enlarged lysosomes through autophagy and the accumulation of lipofuscin. Associated changes are found in the kidney and thyroid. The renal changes are limited to the proximal convoluted tubules and are generally similar to changes found in the liver. The effects on the thyroid are more marked. Although the levels of thyroxine in plasma fail to about half normal values, serum triiodothyronine remains close to normal values while the appearance of the thyroid varies, very marked hyperactivity being noted 7 days after commencement of treatment, this is less marked at 14 days, but even after 9 months treatment there is clear cut evidence for hyperactivity with colloid changes which indicate this has persisted for some time. Straight chain analogs of di-2-ethylhexyl phthalate, di-n-hexyl phthalate and di-n-oxtyl phthalate differ entirely in their short-term effects on the liver and kidney but have similar effects on the thyroid. The short-term in vivo hepatic effects of the three phthalate esters can be reproduced in hepatocytes in tissue culture. All three phthalate esters, as well as clofibrate, have early marked effects on the metabolism of fatty acids in isolated hepatocytes. The nature of these changes is such as to increase storage of lipid in the liver. A hypothesis is presented to explain the progress from these initial metabolic effects to the final formation of liver tumors. Images FIGURE 2. a FIGURE 2. b FIGURE 3a. FIGURE 3b. FIGURE 3c.

Hinton, R H; Mitchell, F E; Mann, A; Chescoe, D; Price, S C; Nunn, A; Grasso, P; Bridges, J W

1986-01-01

149

Fatty acid ethyl esters: markers of alcohol abuse and alcoholism.  

PubMed

Chronic alcoholism, which is associated with hepatic, pancreatic, and myocardial diseases, is one of the major health problems in the United States with high morbidity and mortality. Many individuals who abuse alcohol chronically die even before reaching the clinical stage of the disease. Reliable biomarkers of the diseases induced by chronic alcohol abuse, as well as for alcoholism, currently are not available. In the current study, we measured plasma concentrations of fatty acid ethyl esters [(FAEEs), nonoxidative metabolites of ethanol] in 39 patients with a detectable concentration of alcohol in their blood samples. In turn, we determined the relation of FAEE concentrations with blood alcohol concentration (BAC). Of 39 patients in whom we evaluated this relation, only five had a history of chronic alcohol abuse, and six had a history of acute alcohol abuse. Patients' age ranged from 25 to 71 years. Within this age range, greater concentrations of FAEEs were found in the plasma samples obtained from patients in the 41- to 50-year age group. There were no sex-related differences in BAC, nor in FAEE concentrations. Thirteen patients had a BAC greater than 300 mg%. For 11 patients, the BAC ranged between 200 and 299 mg%, and, for 12 patients, the BAC ranged between 100 and 199 mg%. In comparison with findings for patients with a BAC that ranged between 100 and 299 mg%, the FAEE concentrations were approximately twofold higher in patients with a BAC greater than 300 mg%. Ethyl palmitate and ethyl oleate were the main FAEEs detected in most patients. In general, FAEE concentrations increased with increasing BAC. However, in comparison with patients with a history of acute alcohol abuse, a greater increase in total FAEE concentrations was observed in patients with a history of chronic alcohol abuse (4,250 ng/ml and 15,086 ng/ml, respectively). Fatty acid ethyl esters were either detected in trace amounts or not detectable in the plasma of control subjects with no known alcohol ingestion. These results support our hypothesis that nonoxidative metabolism of ethanol to FAEEs is an important pathway of ethanol disposition during chronic alcohol abuse, and that FAEE concentrations can be a more reliable biomarker of chronic alcohol abuse than a history of acute alcohol abuse. PMID:15902908

Kaphalia, Bhupendra S; Cai, Ping; Khan, M Firoze; Okorodudu, Anthony O; Ansari, G A S

2004-01-01

150

Cinnamyl alcohols and methyl esters of fatty acids from Wedelia prostrata callus cultures.  

PubMed

Two methyl esters of fatty acids, namely octadecanoic acid methyl ester (methyl stearate) and hexadecanoic acid methyl ester (methyl palmitate), in addition to four cinnamyl alcohol derivatives, sinapyl alcohol, coniferyl alcohol, p-coumaryl alcohol and coniferyl alcohol 4-O-glucoside (coniferin), were isolated from callus cultures of Wedelia prostrata. The structure of coniferin was established by spectroscopic and chemical methods, while the other compounds were identified by gas chromatography-mass spectrometry and thin layer chromatography in comparison with standards. PMID:21240761

El-Mawla, Ahmed M A Abd; Farag, Salwa F; Beuerle, Till

2011-01-01

151

Sugar fatty acid esters inhibit biofilm formation by food-borne pathogenic bacteria.  

PubMed

Effects of food additives on biofilm formation by food-borne pathogenic bacteria were investigated. Thirty-three potential food additives and 3 related compounds were added to the culture medium at concentrations from 0.001 to 0.1% (w/w), followed by inoculation and cultivation of five biofilm-forming bacterial strains for the evaluation of biofilm formation. Among the tested food additives, 21 showed inhibitory effects of biofilm formation by Staphylococcus aureus and Escherichia coli, and in particular, sugar fatty acid esters showed significant anti-biofilm activity. Sugar fatty acid esters with long chain fatty acid residues (C14-16) exerted their inhibitory effect at the concentration of 0.001% (w/w), but bacterial growth was not affected at this low concentration. Activities of the sugar fatty acid esters positively correlated with the increase of the chain length of the fatty acid residues. Sugar fatty acid esters inhibited the initial attachment of the S. aureus cells to the abiotic surface. Sugar fatty acid esters with long chain fatty acid residues (C14-16) also inhibited biofilm formation by Streptococcus mutans and Listeria monocytogenes at 0.01% (w/w), while the inhibition of biofilm formation by Pseudomonas aeruginosa required the addition of a far higher concentration (0.1% (w/w)) of the sugar fatty acid esters. PMID:20089325

Furukawa, Soichi; Akiyoshi, Yuko; O'Toole, George A; Ogihara, Hirokazu; Morinaga, Yasushi

2010-03-31

152

Carbodithioic acid esters of fluoxetine, a novel class of dual-function spermicides.  

PubMed

Carbodithioic acid esters of fluoxetine have been prepared by replacing the methylamino function in aminopropane chain with carbodithioic acid ester group and by adding various S-2-hydroxypropyl ester of dialkyl carbodithioic acid at 3-methylamino group. Some of these compounds showed spermicidal, antifungal and anti-Trichomonas activities. The study revealed that incorporation of carbodithioic acid residue directly into fluoxetine structure leads to compounds with better antifungal and anti-Trichomonas activities, and N-methyl-[3-phenyl-3-(4-trifluoromethyl-phenoxy)-propyl]carbodithioic acid S-(2-pyrrolidino-ethyl) ester (14) has shown better profile than both fluoxetine and nonoxynol-9. Further lead optimization may yield a potent dual-function spermicide. PMID:18061311

Kiran Kumar, S T V S; Kumar, Lalit; Sharma, Vishnu L; Jain, Ashish; Jain, Rajeev K; Maikhuri, Jagdamba P; Kumar, Manish; Shukla, Praveen K; Gupta, Gopal

2008-10-01

153

A new method for nanomolar determination of silicic acid in seawater.  

PubMed

A novel method is proposed to determine concentrations of silicic acid in seawater in the nanomolar range of 3-500 nM. It preconcentrates silicic acid through a "Magnesium Induced Co-precipitation" (MAGIC) step before a classical spectrophotometric measurement. The detection limit (3+/-2 nM) is improved by a factor 10 in comparison to the conventional colorimetric methods. The best precision obtained to date is +/-2 nM for a natural sample of 69 nM Si. No interference of phosphate was observed by contrast to previous methods. This simple method offers a simple, sensitive and accurate tool for silicic acid determination in depleted seawater, where its availability remains unknown. PMID:17386784

Rimmelin-Maury, Peggy; Moutin, Thierry; Quguiner, Bernard

2007-03-28

154

Direct Determination of MCPD Fatty Acid Esters and Glycidyl Fatty Acid Esters in Vegetable Oils by LC-TOFMS.  

PubMed

Analysis of MCPD esters and glycidyl esters in vegetable oils using the indirect method proposed by the DGF gave inconsistent results when salting out conditions were varied. Subsequent investigation showed that the method was destroying and reforming MCPD during the analysis. An LC time of flight MS method was developed for direct analysis of both MCPD esters and glycidyl esters in vegetable oils. The results of the LC-TOFMS method were compared with the DGF method. The DGF method consistently gave results that were greater than the LC-TOFMS method. The levels of MCPD esters and glycidyl esters found in a variety of vegetable oils are reported. MCPD monoesters were not found in any oil samples. MCPD diesters were found only in samples containing palm oil, and were not present in all palm oil samples. Glycidyl esters were found in a wide variety of oils. Some processing conditions that influence the concentration of MCPD esters and glycidyl esters are discussed. PMID:21350591

Haines, Troy D; Adlaf, Kevin J; Pierceall, Robert M; Lee, Inmok; Venkitasubramanian, Padmesh; Collison, Mark W

2011-01-01

155

Oxidase-peroxidase enzymes of Datura innoxia. Oxidation of formylphenylacetic acid ethyl ester.  

PubMed Central

An enzyme system from Datura innoxia roots oxidizing formylphenylacetic acid ethyl ester was purified 38-fold by conventional methods such as (NH4)2SO4 fractionation, negative adsorption on alumina Cy gel and chromatography on DEAE-cellulose. The purified enzyme was shown to catalyse the stoicheiometric oxidation of formylphenylacetic acid ethyl ester to benzoylformic acid ethyl ester and formic acid, utilizing molecular O2. Substrate analogues such as phenylacetaldehyde and phenylpyruvate were oxidized at a very low rate, and formylphenylacetonitrile was an inhilating agents, cyanide, thiol compounds and ascorbic acid. This enzyme was identical with an oxidase-peroxidase isoenzyme. Another oxidase-peroxidase isoenzyme which separated on DEAE-chromatography also showed formylphenylacetic acid ethyl ester oxidase activity, albeit to a lesser extent. The properties of the two isoenzymes of the oxidase were compared and shown to differ in their oxidation and peroxidation properties. The oxidation of formylphenylacetic acid ethyl ester was also catalysed by horseradish peroxidase. The Datura isoenzymes exhibited typical haemoprotein spectra. The oxidation of formylphenylacetic acid ethyl ester was different from other peroxidase-catalysed reactions in not being activated by either Mn2+ or monophenols. The oxidation was inhibited by several mono- and poly-phenols and by catalase. A reaction mechanism for the oxidation is proposed.

Kalyanaraman, V S; Mahadevan, S; Kumar, S A

1975-01-01

156

Fatty acid alkyl esters: perspectives for production of alternative biofuels.  

PubMed

The global economy heads for a severe energy crisis: whereas the energy demand is going to rise, easily accessible sources of crude oil are expected to be depleted in only 10-20 years. Since a serious decline of oil supply and an associated collapse of the economy might be reality very soon, alternative energies and also biofuels that replace fossil fuels must be established. In addition, these alternatives should not further impair the environment and climate. About 90% of the biofuel market is currently captured by bioethanol and biodiesel. Biodiesel is composed of fatty acid alkyl esters (FAAE) and can be synthesized by chemical, enzymatic, or in vivo catalysis mainly from renewable resources. Biodiesel is already established as it is compatible with the existing fuel infrastructure, non-toxic, and has superior combustion characteristics than fossil diesel; and in 2008, the global production was 12.2 million tons. The biotechnological production of FAAE from low cost and abundant feedstocks like biomass will enable an appreciable substitution of petroleum diesel. To overcome high costs for immobilized enzymes, the in vivo synthesis of FAAE using bacteria represents a promising approach. This article points to the potential of different FAAE as alternative biofuels, e.g., by comparing their fuel properties. In addition to conventional production processes, this review presents natural and genetically engineered biological systems capable of in vivo FAAE synthesis. PMID:20033403

Rttig, Annika; Wenning, Leonie; Brker, Daniel; Steinbchel, Alexander

2010-02-01

157

Successful treatment of recalcitrant cutaneous sarcoidosis with fumaric acid esters  

PubMed Central

Background Sarcoidosis is a multisystem disease of unknown origin characterized by the formation of noncaseating granulomas, in particular in the lungs, lymph nodes, eyes, and skin. Systemic treatment for cutaneous sarcoidosis can be used for large disfiguring lesions, generalized involvement, or recalcitrant lesions that did not respond to topical therapy. Case presentations We report three patients with recalcitrant cutaneous sarcoidosis who were treated with oral fumaric acid esters (FAE). Three female patients presented with cutaneous sarcoidosis that have proved to be refractory to various therapies, including corticosteroids and chloroquine. We treated the patients with FAE in tablet form using two formulations differing in strength (Fumaderm initial, Fumaderm). Dosage of FAE was performed according to the standard therapy regimen for psoriasis patients. After treatment with FAE (412 months), a complete clearance of skin lesions was achieved in the three patients. The side effects observed in this trial correspond to the well-known spectrum of adverse effects of FAE (flush, minor gastrointestinal complaints, lymphopenia). Conclusions On the basis of our findings FAE therapy seems to be a safe and effective regimen for patients with recalcitrant cutaneous sarcoidosis. Nevertheless further investigations are necessary to confirm our preliminary results.

Nowack, Ute; Gambichler, Thilo; Hanefeld, Christoph; Kastner, Ulrike; Altmeyer, Peter

2002-01-01

158

Treatment of disseminated granuloma annulare with fumaric acid esters  

PubMed Central

Background Granuloma annulare is a granulomatous disease of unknown etiology. Various therapies have been tried in disseminated granuloma annulare (DGA), including corticosteroids, several variants of psoralen plus ultraviolet-A radiation, ultraviolet- A1 radiation, systemic retinoids, and dapsone, with variable success. We report a patient with recalcitrant DGA who was treated with fumaric acid esters (FAE). Case presentation A 40-year old Caucasian woman presented with a 25-year history of recalcitrant DGA. On both legs and the abdomen there were erythematous annular plaques. She was treated with FAE in tablet form using two formulations differing in strength (low strength tablets: 30 mg dimethylfumarate, 67 mg monoethylfumarate Ca salt, 5 mg monoethylfumarate Mg salt, 3 mg monoethylfumarate Zn salt; high strength tablets: 120 mg dimethylfumarate, 87 mg monoethylfumarate Ca salt, 5 mg monoethylfumarate Mg salt, 3 mg monoethylfumarate Zn salt). After three-month therapy, an almost complete clearance of skin lesions was achieved. With the exception of temporary lymphopenia, no adverse effects were observed. The patient remained in remission during a six-month follow up period. Conclusions Our observation has demonstrated that FAE is a potentially beneficial therapeutic option for patients with recalcitrant DGA. However controlled trials are necessary to fully explore the efficacy, optimal dosage, and safety of FAE in the management of DGA.

Kreuter, Alexander; Gambichler, Thilo; Altmeyer, Peter; Brockmeyer, Norbert H

2002-01-01

159

Concentration of Stearidonic Acid in Free Fatty Acid and Fatty Acid Ethyl Ester Forms from Modified Soybean Oil by Winterization  

Microsoft Academic Search

The concentration of stearidonic acid (SDA, 18:4 ?-3) in free fatty acid (FFA) and fatty acid ethyl ester (FAEE) forms by\\u000a low temperature crystallization (winterization) was studied. For this purpose, modified soybean oil (initial SDA content,~23%)\\u000a was transformed into its corresponding FFA and FAEE by chemical hydrolysis and ethanolysis, respectively. In the first study,\\u000a the FFA and FAEE were used

Luis Vzquez; Casimir C. Akoh

160

75 FR 20785 - Polyglyceryl Phthalate Ester of Coconut Oil Fatty Acids; Exemption from the Requirement of a...  

Federal Register 2010, 2011, 2012, 2013

...EPA-HQ-OPP-2008-0888; FRL-8436-3] Polyglyceryl Phthalate Ester of Coconut Oil Fatty Acids; Exemption...July 8, 2009, concerning polyglyceryl phthalate ester of coconut oil fatty acids; exemption...requirement of a tolerance for ``polyglyceryl phthalate ester of coconut oil fatty...

2010-04-21

161

A Study of the AluminaSilica Gel Adsorbent for the Removal of Silicic Acid from Geothermal Water: Increase in Adsorption Capacity of the Adsorbent due to Formation of Amorphous Aluminosilicate by Adsorption of Silicic Acid  

Microsoft Academic Search

Two kinds of adsorbents (Si adsorbent and Al adsorbent) for the removal of silicic acid from geothermal water to retard the formation of silica scales were prepared using silicic acid contained in geothermal water. The Si adsorbent was prepared by evaporating geothermal water, and the Al adsorbent was prepared by evaporating geothermal water after the addition of aluminum chloride. The

Takushi Yokoyama; Akira Ueda; Koichi Kato; Katsumi Mogi; Shorin Matsuo

2002-01-01

162

Simultaneous analysis of free phytosterols/phytostanols and intact phytosteryl/phytostanyl fatty acid and phenolic acid esters in cereals.  

PubMed

An approach based on solid-phase extraction for the effective separation of free phytosterols/phytostanols and phytosteryl/phytostanyl fatty acid and phenolic acid esters from cereal lipids was developed. The ester conjugates were analyzed in their intact form by means of capillary gas chromatography. Besides free sterols and stanols, up to 33 different fatty acid and phenolic acid esters were identified in four different cereal grains via gas chromatography-mass spectrometry. The majority (52-57%) of the sterols and stanols were present as fatty acid esters. The highest levels of all three sterol and stanol classes based on dry matter of ground kernels were determined in corn, whereas the oil extract of rye was 1.7 and 1.6 times richer in fatty acid esters and free sterols/stanols than the corn oil. The results showed that there are considerable differences in the sterols/stanols and their ester profiles and contents obtained from corn compared to rye, wheat, and spelt. The proposed method is useful for the quantification of a wide range of free phytosterols/phytostanols and intact phytosteryl/phytostanyl esters to characterize different types of grain. PMID:22524687

Esche, Rebecca; Barnsteiner, Andreas; Scholz, Birgit; Engel, Karl-Heinz

2012-05-30

163

Synthesis of fatty acid sterol esters using cholesterol esterase from Trichoderma sp. AS59.  

PubMed

We recently reported the characterization of novel cholesterol esterase (EC. 3.1.1.13) from Trichoderma sp. and preliminary work on sterol ester synthesis. In the present study, we further examined the enzyme ability to synthesize cholesterol esters from cholesterol and free fatty acids of various chain lengths, and compared the fatty acid specificity in synthesis with that in hydrolysis. The enzyme catalyzed the synthesis of medium- and long-chain fatty acid cholesterol esters, but failed to synthesize short-chain fatty acid esters. The fatty acid specificities in the synthesis and hydrolysis of cholesterol esters were entirely different from each other. Unlike other lipolytic enzymes, the enzyme was largely independent of water content in the synthesis of cholesterol oleate, and it achieved near-complete esterification in the presence of an equimolar excess of oleic acid. Of additional interest is the finding that the addition of n-hexane markedly enhanced the esterification activities on all the medium- and long-chain saturated fatty acids used. Based on these findings, we attempted to synthesize stigmasterol stearate as a food additive to lower cholesterol levels in blood plasma, and found that the enzyme catalyzed effective synthesis of the ester without the need of dehydration during the reaction, indicating the potential utility of the enzyme in the food industry. PMID:22113022

Morinaga, Naoya; Maeda, Atsushi; Mizuno, Takayuki; Bunya, Masanori; Sugihara, Shigeo; Sugihara, Akio

2011-05-01

164

Process for Preserving Raw Fruits and Vegetables Using Ascorbic Acid Esters and Compositions Thereof.  

National Technical Information Service (NTIS)

The invention relates to the preservation of raw fruits, vegetables and their juices. More particularly, the invention relates to the use of certain ascorbic acid esters, and compositions thereof, to control enzymatic browning in raw fruit and vegetable p...

G. M. Sapers K. B. Hicks P. A. Seib

1987-01-01

165

Process for Preserving Raw Fruits and Vegetables Using Ascorbic Acid Esters and Compositions Thereof.  

National Technical Information Service (NTIS)

The present invention relates to the preservation of raw fruits, vegetables and their juices. More particularly, the present invention relates to the use of certain ascorbic acid esters, and compositions thereof, to control enzymatic browning in raw fruit...

G. M. Sapers K. B. Hicks P. A. Seib

1987-01-01

166

Premixed ignition behavior of C{sub 9} fatty acid esters: A motored engine study  

SciTech Connect

An experimental study on the premixed ignition behavior of C{sub 9} fatty acid esters has been conducted in a motored CFR engine. For each test fuel, the engine compression ratio was gradually increased from the lowest point (4.43) to the point where significant high temperature heat release (HTHR) was observed. The engine exhaust was sampled and analyzed through GC-FID/TCD and GC-MS. Combustion analysis showed that the four C{sub 9} fatty acid esters tested in this study exhibited evidently different ignition behavior. The magnitude of low temperature heat release (LTHR) follows the order, ethyl nonanoate > methyl nonanoate >> methyl 2-nonenoate > methyl 3-nonenoate. The lower oxidation reactivity for the unsaturated fatty acid esters in the low temperature regime can be explained by the reduced amount of six- or seven-membered transition state rings formed during the oxidation of the unsaturated esters due to the presence of a double bond in the aliphatic chain of the esters. The inhibition effect of the double bond on the low temperature oxidation reactivity of fatty acid esters becomes more pronounced as the double bond moves toward the central position of the aliphatic chain. GC-MS analysis of exhaust condensate collected under the engine conditions where only LTHR occurred showed that the alkyl chain of the saturated fatty acid esters participated in typical paraffin-like low temperature oxidation sequences. In contrast, for unsaturated fatty acid esters, the autoignition can undergo olefin ignition pathways. For all test compounds, the ester functional group remains largely intact during the early stage of oxidation. (author)

Zhang, Yu.; Yang, Yi; Boehman, Andre L. [EMS Energy Institute, The Pennsylvania State University, University Park, PA 16802 (United States)

2009-06-15

167

Enzymatic synthesis of carbohydrate esters of fatty acid (I) esterification of sucrose, glucose, fructose and sorbitol  

Microsoft Academic Search

The authors attempted to synthesize carbohydrate esters of fatty acids enzymatically in order to overcome the problems associated\\u000a with the chemical processes for the synthesis of commercial sucrose esters. The enzymes used were lipases from microorganisms\\u000a belonging toRhyzopus, Enterbacterium, Aspergillus, Pseudomonas, Chromobacterium, Candida, Mucor andPenicillium. Fatty acids (stearic, oleic and linoleic) and carbohydrates (sucrose, glucose, fructose and sorbitol) used for

Hajime Seino; Tsuyoshi Uchibori; Toshiyuki Nishitani; Sachiko Inamasu

1984-01-01

168

Application of aminoacylase I to the enantioselective resolution of ?-amino acid esters and amides  

Microsoft Academic Search

Aminoacylase I from Aspergillus melleus, a readily available and inexpensive enzyme mainly used in the industrial production of enantiopure l-amino acids from their N-acetyl derivatives, is shown to hydrolyze the esters and amides of natural and non-natural amino acids with high enantioselectivity (for the ester hydrolysis, E is up to 76, in case of amides E >300). The reaction rates

Maxim I Youshko; Luuk M van Langen; Roger A Sheldon; Vytas K vedas

2004-01-01

169

Fatty Acid Phytyl Ester Synthesis in Chloroplasts of Arabidopsis[W  

PubMed Central

During stress or senescence, thylakoid membranes in chloroplasts are disintegrated, and chlorophyll and galactolipid are broken down, resulting in the accumulation of toxic intermediates, i.e., tetrapyrroles, free phytol, and free fatty acids. Chlorophyll degradation has been studied in detail, but the catabolic pathways for phytol and fatty acids remain unclear. A large proportion of phytol and fatty acids is converted into fatty acid phytyl esters and triacylglycerol during stress or senescence in chloroplasts. We isolated two genes (PHYTYL ESTER SYNTHASE1 [PES1] and PES2) of the esterase/lipase/thioesterase family of acyltransferases from Arabidopsis thaliana that are involved in fatty acid phytyl ester synthesis in chloroplasts. The two proteins are highly expressed during senescence and nitrogen deprivation. Heterologous expression in yeast revealed that PES1 and PES2 have phytyl ester synthesis and diacylglycerol acyltransferase activities. The enzymes show broad substrate specificities and can employ acyl-CoAs, acyl carrier proteins, and galactolipids as acyl donors. Double mutant plants (pes1 pes2) grow normally but show reduced phytyl ester and triacylglycerol accumulation. These results demonstrate that PES1 and PES2 are involved in the deposition of free phytol and free fatty acids in the form of phytyl esters in chloroplasts, a process involved in maintaining the integrity of the photosynthetic membrane during abiotic stress and senescence.

Lippold, Felix; vom Dorp, Katharina; Abraham, Marion; Holzl, Georg; Wewer, Vera; Yilmaz, Jenny Lindberg; Lager, Ida; Montandon, Cyrille; Besagni, Celine; Kessler, Felix; Stymne, Sten; Dormann, Peter

2012-01-01

170

Synthesis of an acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters  

DOEpatents

A process of preparing an acid addition salt of delta-aminolevulinic acid comprising: dissolving a lower alkyl 5-bromolevulinate and an alkali metal diformylamide in an organic solvent selected from the group consisting of acetonitrile, methanol, tetrahydrofuran, 2-methyltetrahydrofuran and methylformate or mixtures thereof to form a suspension of an alkyl 5-(N,N-diformylamino) levulinate ester; and hydrolyzing said alkyl 5-(N,N-diformylamino) levulinate with an inorganic acid to form an acid addition salt of delta-amino levulinic acid.

Moens, Luc (Lakewood, CO)

1999-01-01

171

Synthesis of an acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters  

DOEpatents

A process is disclosed for preparing an acid addition salt of delta-aminolevulinic acid comprising. The process involves dissolving a lower alkyl 5-bromolevulinate and an alkali metal diformylamide in an organic solvent selected from the group consisting of acetonitrile, methanol, tetrahydrofuran, 2-methyltetrahydrofuran and methylformate or mixtures to form a suspension of an alkyl 5-(N,N-diformylamino) levulinate ester; and hydrolyzing the alkyl 5-(N,N-diformylamino) levulinate with an inorganic acid to form an acid addition salt of delta-amino levulinic acid.

Moens, L.

1999-05-25

172

Larvicidal activity of fatty acid methyl esters of Vitex species against Culex quinquefasciatus  

Microsoft Academic Search

The larvicidal activity of fatty acid methyl ester (FAME) extracts of Vitex altissima, Vitex negundo and Vitex trifolia was studied against early fourth-instar larvae of Culex quinquefasciatus. The fatty composition was analysed by gas chromatography. The highest percentage of lauric acid, palmitic acid, stearic\\u000a acid, oleic acid and linolenic acid were recorded in V. negundo. The highest percentage of linolenic

Krishnan Kannathasan; Annadurai Senthilkumar; Venugopalan Venkatesalu; Manivachagam Chandrasekaran

2008-01-01

173

AMINO ACID BASED BIOANALOGOUS POLYMERS. SYNTHESIS AND STUDY OF NEW POLY(ESTER AMIDE)S COMPOSED OF HYDROPHOBIC ?-AMINO ACIDS AND DIANHYDROHEXITOLES  

Microsoft Academic Search

A new class of biodegradable poly(ester-amide)s was prepared by a two step method. At first isosorbide or isomannide were esterified with ?-amino acids in the presence of p-toluenesulfonic acid, and the resulting esters bisammonium tosylates were isolated. Second, the amino groups were liberated and polycondensed with p-nitrophenyl esters of aliphatic dicarboxylic acids. The resulting poly(ester-amide)s were characterized by elemental analyses,

Z. Gomurashvili; H. R. Kricheldorf; R. Katsarava

2000-01-01

174

Impact of esters of mono- and dicarboxylic acids on diesel fuel quality  

SciTech Connect

The objective of this work was to assess how esters of mono- and dicarboxylic acids of different structure affect diesel fuel quality, by measuring cetane numbers and cold flow properties of blends of the esters under investigation with gasoil. An increase in either the chain length of the normal alcohol used for the esterification or the chain length of the mono- or dicarboxylic acid involved in the esterification improves the cetane number. Among the fatty acid esters of the same molecular type, those having the carboxylic group close to one end of the molecule have better ignition quality, whereas those having the ester group around the middle of the molecule appear to have better cold flow performance. Oleates combine good ignition quality with adequate cold flow performance, whereas the high oxygen content of some diesters seems to be an extra advantage.

Serdari, A.; Lois, E.; Stournas, S. [National Technical Univ. of Athens (Greece)] [National Technical Univ. of Athens (Greece)

1999-09-01

175

The Novel Formation of Ordered and Varied Silica-Imidazole Complexes from Silicic Acid  

Microsoft Academic Search

Fixed quantities of silicic acid in isopropyl alcohol were treated with varying amounts of imidazole in the same solvent, left closed till complexation was complete (?7 days) and the resulting gels on slow evaporation (?30 days) afforded glassy solids, ranging from nodules to tubules, as seen by scanning electron microscope (SEM). In another strategy where soluble oligomers of silica along

S. Ranganathan; S. M. Babu; P. R. Bangal; S. Madhavendra; S. R. Voleti

2011-01-01

176

Selective Oxidation of Benzoins with Chromic Acid Supported on Aluminum Silicate Under Viscous Conditions  

Microsoft Academic Search

Efficient oxidation of benzoins to corresponding benzils using chromic acid supported on aluminum silicate reagent under viscous conditions at room temperature is described, and all the reactions are completed within 3 hours in yields between 8292%. The present procedure can overcome the problems existed in the common solvent-free reactions of the difficulty for the solid molecular collision to react. In

Ji-Dong Lou; Yi-Chun Ma; Qiang Wang; Negin Vatanian; Changhe Zhang

2010-01-01

177

Branched Chain Amino Acid Metabolism in the Biosynthesis of Lycopersicon pennellii Glucose Esters 1  

PubMed Central

Lycopersicon pennellii Corr. (D'Arcy) an insect-resistant, wild tomato possesses high densities of glandular trichomes which exude a mixture of 2,3,4-tri-O-acylated glucose esters that function as a physical impediment and feeding deterrent to small arthropod pests. The acyl moieties are branched C4 and C5 acids, and branched and straight chain C10, C11, and C12 acids. The structure of the branched acyl constituents suggests that the branched chain amino acid biosynthetic pathway participates in their biosynthesis. [14C]Valine and deuterated branched chain amino acids (and their oxo-acid derivatives) were incorporated into branched C4 and C5 acid groups of glucose esters by a process of transamination, oxidative decarboxylation and subsequent acylation. C4 and C5 branched acids were elongated by two carbon units to produce the branched C10-C12 groups. Norvaline, norleucine, allylglycine, and methionine also were processed into acyl moieties and secreted from the trichomes as glucose esters. Changes in the acyl composition of the glucose esters following sulfonylurea herbicide administration support the participation of acetohydroxyacid synthetase and the other enzymes of branched amino acid biosynthesis in the production of glucose esters.

Walters, Donald S.; Steffens, John C.

1990-01-01

178

21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.  

Code of Federal Regulations, 2013 CFR

...purpose of this section, partial phosphoric acid esters of polyester resins are prepared by...of the resin thus produced with phosphoric acid anhydride to produce a resin having an acid number of 81 to 98 and a phosphorus content of...

2013-04-01

179

21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.  

Code of Federal Regulations, 2010 CFR

...purpose of this section, partial phosphoric acid esters of polyester resins are prepared by...of the resin thus produced with phosphoric acid anhydride to produce a resin having an acid number of 81 to 98 and a phosphorus content of...

2010-01-01

180

21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.  

Code of Federal Regulations, 2010 CFR

...purpose of this section, partial phosphoric acid esters of polyester resins are prepared by...of the resin thus produced with phosphoric acid anhydride to produce a resin having an acid number of 81 to 98 and a phosphorus content of...

2009-04-01

181

Synthesis of cellulose-fatty acid esters for use as biodegradable plastics  

Microsoft Academic Search

Long-chain fatty acid carbohydrate esters (FACE) were synthesized by the acid chloride-pyridine reaction to different degrees of substitution (DS). The hydrolyzed soybean oil was used as the source of unsaturated fatty acids. High molecular weight FACE polymers are insoluble in common solvents, such as benzene, toluene, THF, etc., and are highly water resistant. However, FACE polymers of hydrolyzed cellulose (MW

Pinglang Wang; Bernard Y. Tao

1995-01-01

182

40 CFR 721.9965 - Fatty acids, C10-13 - branched, vinyl esters.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Fatty acids, C10-13 - branched, vinyl esters...Chemical Substances § 721.9965 Fatty acids, C10-13 - branched, vinyl...chemical substance identified as fatty acids, C10-13 - branched,...

2013-07-01

183

Selected Gamma Aminobutyric Acid (GABA) Esters may Provide Analgesia for Some Central Pain Conditions  

PubMed Central

Central pain is an enigmatic, intractable condition, related to destruction of thalamic areas, resulting in likely loss of inhibitory synaptic transmission mediated by GABA. It is proposed that treatment of central pain, a localized process, may be treated by GABA supplementation, like Parkinsons disease and depression. At physiologic pH, GABA exists as a zwitterion that is poorly permeable to the blood brain barrier (BBB). Because the pH of the cerebral spinal fluid (CSF) is acidic relative to the plasma, ion trapping may allow a GABA ester prodrug to accumulate and be hydrolyzed within the CSF. Previous investigations with ester local anesthetics may be applicable to some GABA esters since they are weak bases, hydrolyzed by esterases and cross the BBB. Potential non-toxic GABA esters are discussed. Many GABA esters were investigated in the 1980s and it is hoped that this paper may spark renewed interest in their development.

Goldberg, Joel S.

2010-01-01

184

In vitro pharmacokinetics of anti-psoriatic fumaric acid esters  

PubMed Central

Background Psoriasis is a chronic inflammatory skin disease that can be successfully treated with a mixture of fumaric acid esters (FAE) formulated as enteric-coated tablets for oral use. These tablets consist of dimethylfumarate (DMF) and salts of monoethylfumarate (MEF) and its main bioactive metabolite is monomethylfumarate (MMF). Little is known about the pharmacokinetics of these FAE. The aim of the present study was to investigate the hydrolysis of DMF to MMF and the stability of MMF, DMF and MEF at in vitro conditions representing different body compartments. Results DMF is hydrolyzed to MMF in an alkaline environment (pH 8), but not in an acidic environment (pH 1). In these conditions MMF and MEF remained intact during the period of analysis (6 h). Interestingly, DMF was hardly hydrolyzed to MMF in a buffer of pH 7.4, but was rapidly hydrolyzed in human serum having the same pH. Moreover, in whole blood the half-life of DMF was dramatically reduced as compared to serum. The concentrations of MMF and MEF in serum and whole blood decreased with increasing time. These data indicate that the majority of the FAE in the circulation are metabolized by one or more types of blood cells. Additional experiments with purified blood cell fractions resuspended in phosphate buffered saline (pH 7.4) revealed that at concentrations present in whole blood monocytes/lymphocytes, but not granulocytes and erythrocytes, effectively hydrolyzed DMF to MMF. Furthermore, in agreement with the data obtained with the pure components of the tablet, the enteric-coated tablet remained intact at pH 1, but rapidly dissolved at pH 8. Conclusion Together, these in vitro data indicate that hydrolysis of DMF to MMF rapidly occurs at pH 8, resembling that within the small intestines, but not at pH 1 resembling the pH in the stomach. At both pHs MMF and MEF remained intact. These data explain the observation that after oral FAE intake MMF and MEF, but not DMF, can be readily detected in the circulation of human healthy volunteers and psoriasis patients.

Litjens, Nicolle HR; van Strijen, Elisabeth; van Gulpen, Co; Mattie, Herman; van Dissel, Jaap T; Thio, H Bing; Nibbering, Peter H

2004-01-01

185

Polymers from amino acids: development of dual ester-urethane melt condensation approach and mechanistic aspects.  

PubMed

A new dual ester-urethane melt condensation methodology for biological monomers-amino acids was developed to synthesize new classes of thermoplastic polymers under eco-friendly and solvent-free polymerization approach. Naturally abundant L-amino acids were converted into dual functional ester-urethane monomers by tailor-made synthetic approach. Direct polycondensation of these amino acid monomers with commercial diols under melt condition produced high molecular weight poly(ester-urethane)s. The occurrence of the dual ester-urethane process and the structure of the new poly(ester-urethane)s were confirmed by (1)H and (13)C NMR. The new dual ester-urethane condensation approach was demonstrated for variety of amino acids: glycine, ?-alanine, L-alanine, L-leucine, L-valine, and L-phenylalanine. MALDI-TOF-MS end group analysis confirmed that the amino acid monomers were thermally stable under the melt polymerization condition. The mechanism of melt process and the kinetics of the polycondensation were studied by model reactions and it was found that the amino acid monomer was very special in the sense that their ester and urethane functionality could be selectively reacted by polymerization temperature or catalyst. The new polymers were self-organized as ?-sheet in aqueous or organic solvents and their thermal properties such as glass transition temperature and crystallinity could be readily varied using different l-amino acid monomers or diols in the feed. Thus, the current investigation opens up new platform of research activates for making thermally stable and renewable engineering thermoplastics from natural resource amino acids. PMID:22713137

Anantharaj, S; Jayakannan, M

2012-08-13

186

Downregulation of Inflammatory Responses by Novel Caffeic Acid Ester Derivative by Inhibiting NF-kappa B  

Microsoft Academic Search

IntroductionConsidering anti-tumorigenic activity of caffeic acid phenyl ester, synthesis of several esterified form of caffeic acid is\\u000a a novel approach in designing for potent drugs.\\u000a \\u000a \\u000a \\u000a ResultsOur study demonstrates that esterified caffeic acid with methyl vanillate, termed as caffeic acid methyl vanillate ester (CAMVE),\\u000a blocked inflammatory stimuli-induced inflammatory responses. It decreased amounts of iNOS, Cox-2, and ICAM1 by inhibiting\\u000a NF-?B through

Julie S. Bose; Vijay Gangan; Swatantra Kumar Jain; Sunil K. Manna

2009-01-01

187

Mass spectra of acetylenic fatty acid methyl esters and derivatives.  

PubMed

A series of isomeric methyl octadecynoates was analyzed by mass spectrometry; each isomer gave a unique spectrum. The characteristic ions were those resulting from a McLafferty rearrangement of the allenic sites or of the already-rearranged allenic sites. The acetylenic esters were also subjected to oxymercuration whereupon a carbonyl group was formed at either of the original actylenic carbon atoms providing two oxostearates. Further reaction with NaBH4 formed hydroxy esters which, after silylation, gave diagnostic mass spectra indicative of the triple bond location. Applied to esters with both double and triple bonds, this procedure permitted differentiation between the two types of unsaturation. Methoxyl groups marked the original double bond locations and hydroxyls did so for triple bonds. PMID:972578

Kleiman, R; Bohannon, M B; Gunstone, F D; Barve, J A

1976-08-01

188

Kinetics of sulfuric acid leaching of low-grade zinc silicate ore  

Microsoft Academic Search

The results of a leaching kinetics study of low-grade zinc silicate ore with sulfuric acid are presented. Effect of ore particle size, reaction temperature, and acid concentration on zinc dissolution rate were determined. The results obtained show that leaching of about 94% of zinc is achieved using ?200+270 mesh ore particle size at a reaction temperature of 70C for 180

E. A Abdel-Aal

2000-01-01

189

Gas-Liquid Chromatographic Analysis of Indole-3-acetic Acid Myoinositol Esters in Maize Kernels 1  

PubMed Central

An improved method of fractionating the myoinositol esters of indoleacetic acid (IAA) from maize kernels by gas-liquid chromatography has been developed. Mass spectrometry was employed as an aid in identification of the esters. Maize kernels contain three groups of esters of IAA: (a) IAA myoinositols, (b) IAA myoinositol arabinosides, and (c) IAA myoinositol galactosides. Each group has three chromatographically distinguishable isomers. The glycosylinositols described are unique in that carbon 1 of the sugar is attached to the hydroxyl at C-5 of the myoinositol.

Ueda, Minoru; Ehmann, Axel; Bandurski, Robert S.

1970-01-01

190

New tetrazole-1-acetic acid esters for enzymatic synthesis of cefazolin  

Microsoft Academic Search

The enzymatic synthesis of cefazolin (CEZ) using esters of tetrazole-1-acetic acid (TzAA esters) with saturated lower alcohols\\u000a is reported. The optimum ratios of acyl-donor:acyl-acceptor in the enzymatic synthesis were determined. It is shown that a\\u000a threefold molar excess of acyl-donor for about 165 min, a conversion rate of about 55% is obtained with these TzAA esters.\\u000a The syntheses were carried

M. Kostadinov; A. Nikolov; N. Tsoneva; N. Petkov

1992-01-01

191

Myo-inositol esters of indole-3-acetic acid are endogenous components of Zea mays L. shoot tissue  

NASA Technical Reports Server (NTRS)

Indole-3-acetyl-myo-inositol esters have been demonstrated to be endogenous components of etiolated Zea mays shoots tissue. This was accomplished by comparison of the putative compounds with authentic, synthetic esters. The properties compared were liquid and gas-liquid chromatographic retention times and the 70-ev mass spectral fragmentation pattern of the pentaacetyl derivative. The amount of indole-3-acetyl-myo-inositol esters in the shoots was determined to be 74 nanomoles per kilogram fresh weight as measured by isotope dilution, accounting for 19% of the ester indole-3-acetic acid of the shoot. This work is the first characterization of an ester conjugate of indole-3-acetate acid from vegetative shoot tissue using multiple chromatographic properties and mass spectral identification. The kernel and the seedling shoot both contain indole-3-acetyl-myo-inositol esters, and these esters comprise approximately the same percentage of the total ester content of the kernel and of the shoot.

Chisnell, J. R.

1984-01-01

192

The influence of esters and carboxylic acids as the N-substituent of opioids. 1. Benzomorphans  

PubMed Central

To investigate the effects of carboxylic ester and acid moieties as the N-substituent of opioids, a short series of racemic N-substituted normetazocines was prepared. The introduction of both groups as the normetazocine N-substituent produced compounds which displayed low potency in vitro and in vivo, with the esters displaying the greater activity. The pharmacology of the compounds is discussed with implications resulting from potential in vivo metabolic hydrolysis.

Metcalf, Matthew D.; Aceto, Mario D.; Harris, Louis S.; Woods, James H.; Traynor, John R; Coop, Andrew; May, Everette L.

2008-01-01

193

Carotenol fatty acid esters: easy substrates for digestive enzymes?  

PubMed

To study the specificity of gastric lipases on carotenoid mono- and diesters, an enzymatic assay was applied. Digestions were carried out in phosphate buffer at pH 7.4 and 37 degrees C. As substrates we employed oleoresins from marigold (Tagetes erecta L.; lutein diesters), red paprika (Capsicum annuum L., mainly capsanthin diesters), papaya (Carica papaya L.; beta-cryptoxanthin esters), and loquat (Eriobotrya japonica Lindl.; beta-cryptoxanthin esters) as well as retinyl palmitate. These were reacted with porcine pancreatic lipase, porcine pancreatin, porcine cholesterol esterase, and human pancreatic lipase. As reference enzyme a yeast lipase from Candida rugosa was applied. A high turnover could be observed with porcine pancreatic lipase and porcine cholesterol esterase, indicating cholesterol esterase to be a plausible candidate for generation of free carotenoids in the gut. Human pancreatic lipase accepted only retinyl palmitate as substrate, carotenoid mono- and diesters were not hydrolyzed. The assay permits an approach for calculation of enzymatic activities towards carotenoid esters as substrates for the first time, which is based on the amount of enzyme formulation, present in the assay (U/mg solid). Furthermore, these studies provide deeper insight into carotenoid ester bioaccessibility. PMID:12128058

Breithaupt, Dietmar E; Bamedi, Ameneh; Wirt, Ursula

2002-08-01

194

Kinetics of base hydrolysis of ?-amino acid esters catalyzed by [Pd(Et4en)(H2O)2  

Microsoft Academic Search

The kinetics of base hydrolysis of amino acid esters, glycine-, histidine-, and methionine methyl esters in the presence of [Pd(Et4en))(H2O)2] is studied in aqueous solution at 25C and I = 0.1 mol dm (Et4en = N,N,N?,N?-tetraethylethylenediamine). The rate of ester hydrolysis for glycine methyl ester is studied at different temperatures and dioxanewater solutions of different compositions. The kinetic data fit

Mohamed M. Shoukry; Abdul Aziz Al-Najjar; Wafaa M. Hosny; Afkar K. Abdel Hadi; Afaf A. Mahgoub; Perihan A. Khalf Alla

2010-01-01

195

Characterization of modified calcium-silicate cements exposed to acidic environment  

SciTech Connect

Portland cement which is used as a binder in concrete in the construction industry has been developed into a biomaterial. It is marketed as mineral trioxide aggregate and is used in dentistry. This material has been reported to be very biocompatible and thus its use has diversified. The extended use of this material has led to developments of newer versions with improved physical properties. The aim of this study was to evaluate the effect of acidic environments found in the oral cavity on fast setting calcium silicate cements with improved physical properties using a combination of techniques. Two fast setting calcium silicate cements (CSA and CFA) and two cement composites (CSAG and CFAG) were assessed by subjecting the materials to lactic acid/sodium lactate buffer gel for a period of 28 days. At weekly intervals the materials were viewed under the tandem scanning confocal microscope (TSM), and scanning electron microscope (SEM). The two prototype cements exhibited changes in their internal chemistry with no changes in surface characteristics. Since the changes observed were mostly sub-surface evaluation of surface characteristics of cement may not be sufficient in the determination of chemical changes occurring. - Research Highlights: {yields} An acidic environment affects modified fast setting calcium silicate-based cements. {yields} No surface changes are observed in acidic environment. {yields} An acidic environment causes sub-surface changes in the material chemistry which are only visible in fractured specimens. {yields} A combination of techniques is necessary in order to evaluate the chemical changes occurring.

Camilleri, Josette, E-mail: josette.camilleri@um.edu.mt

2011-01-15

196

In situ assembled boronate ester assisted chiral carboxylic acid catalyzed asymmetric trans-aziridinations.  

PubMed

We developed herein a new chiral Brnsted acid catalyst which is composed of two independent organic molecules, a chiral diol, and 2-boronobenzoic acid. In situ formation of a boronate ester was utilized as a key process to generate an active catalyst. This boronate ester assisted chiral carboxylic acid catalyst was successfully applied to the trans-aziridination of N-Boc and N-benzyl imines with N-phenyldiazoacetamide. This is the first catalyst to achieve high enantioselectivities using N-benzyl imines. PMID:24199743

Hashimoto, Takuya; Glvez, Alberto Osuna; Maruoka, Keiji

2013-11-27

197

The Southern Ocean silicon trap: Data-constrained estimates of regenerated silicic acid, trapping efficiencies, and global transport paths  

NASA Astrophysics Data System (ADS)

We analyze an optimized model of the global silicon cycle embedded in a data-assimilated steady ocean circulation. Biological uptake is modeled by conditionally restoring silicic acid in the euphotic zone to observed concentrations where the modeled concentrations exceed the observational climatology. An equivalent linear model is formulated to which Green-function-based transport diagnostics are applied. We find that the models' opal export through 133 m depth is 166 24 Tmol Si/yr, with the Southern Ocean (SO) providing 70% of this export, 50% of which dissolves above 2000 m depth. The global-scale gradients of the opal dissolution rate are primarily meridional, while the global-scale gradients of phosphate remineralization are primarily vertical. The mean depth of the temperature-dependent silicic-acid regeneration reaches 2300 m in the SO, compared to 600 m for phosphate remineralization. Silicic acid is stripped out of the euphotic zone far more efficiently than phosphate, with only (34 5)% of the global silicic-acid inventory being preformed, compared to (61 7)% for phosphate. Subantarctic and tropical waters contribute most of the ocean's regenerated silicic acid, while Antarctic waters provide most of the preformed silicic acid. About half of the global silicic-acid inventory is trapped in transport paths connecting successive SO utilizations, with silicic acid last utilized in the SO having only a (5 2)% chance of being next utilized outside the SO. This trapping depletes subantarctic mode waters of silicic acid relative to phosphate, which has a (44 2)% probability of escaping successive SO utilization.

Holzer, Mark; Primeau, Franois W.; DeVries, Timothy; Matear, Richard

2014-01-01

198

Synthesis and in vitro transdermal penetration enhancing activity of lactam N-acetic acid esters.  

PubMed

A homologous series of N-acetic acid esters of 2-pyrrolidinone and 2-piperidinone has been prepared and evaluated for its ability to enhance the skin content and flux of hydrocortisone 21-acetate in hairless mouse skin in vitro. Enhancement ratios (ER) were determined for flux (J), 24-hour diffusion cell receptor cell concentrations (Q24), and 24-h full-thickness mouse skin steroid content (SC) and compared to control values (no enhancer present). In addition, in an attempt to abrogate toxicity, these dermal penetration enhancers were designed to have the potential for biodegradation by dermal esterases. 2-Oxopyrrolidine-alpha acetic acid dodecyl ester (5) showed the highest enhancement ratios for J (ER 67.33) and Q24 (ER 180.66). 2-Oxopiperidine-alpha-acetic acid decyl ester (10) showed a high Q24 (ER 162.07) but a lower J (ER 12.67). 2-Oxopyrrolidine-alpha-acetic acid decyl ester (3) showed the highest enhancement ratio for SC (ER 8.7). The ER Q24 for 3, 5 and 10, as well as other lactam N-acetic acid esters in this work, were significantly higher than the ER found using Azone as enhancer. PMID:8683439

Michniak, B B; Player, M R; Sowell, J W

1996-02-01

199

Fuel and lubricant additives from acid treated mixtures of vegetable oil derived amides and esters  

SciTech Connect

Vegetable oils such as corn oil, peanut oil, and soy oil are reacted with polyamines to form a mixture containing amides, imides, half esters, and glycerol with subsequent treatment with a strong acid such as sulfonic acid to produce a product mix that has good detergent properties in fuels and lubricants.

Bonazza, B.R.; Devault, A.N.

1981-05-26

200

Fatty acid ethyl esters are present in human serum after ethanol ingestion  

Microsoft Academic Search

The aim of the study was to determine whether fatty acid ethyl esters, nonoxidative products of ethanol metabolism selectively present in organs damaged by ethanol abuse, are de- tectable in the serum after ethanol ingestion. Serum samples of hospital emergency room patients with positive (n = 32) and negative (n = 5) blood ethanol levels were assayed for fatty acid

Kathleen M. Doyle; David A. Bird; Salih Al-Salihi; Youseff Hallaq; Joanne E. Cluette-Brown; Kendrick A. Goss; Michael Laposata

201

Preanalytical Variables Affecting the Quantification of Fatty Acid Ethyl Esters in Plasma and Serum Samples  

Microsoft Academic Search

Background: Fatty acid ethyl esters (FAEEs) are cyto- toxic nonoxidative ethanol metabolites produced by esterification of fatty acids and ethanol. FAEEs are detectable in blood up to 24 h after ethanol consump- tion. The objective of this study was to assess the impact of gender, serum or plasma triglyceride concentration, time and temperature of specimen storage, type of alcoholic beverage

Britt L. Soderberg; Ewa T. Sicinska; Emily Blodget; Joanne E. Cluette-Brown; Paolo M. Suter; Theresa Schuppisser; Wilhem Vetter; Michael Laposata

202

Facile synthesis of acid-labile polymers with pendent ortho esters.  

PubMed

This work presents a facile approach for preparation of acid-labile and biocompatible polymers with pendent cyclic ortho esters, which is based on the efficient and mild reactions between cyclic ketene acetal (CKA) and hydroxyl groups. Three CKAs, 2-ethylidene-1,3-dioxane (EDO), 2-ethylidene-1,3-dioxolane (EDL), and 2-ethylidene-4- methyl-1,3-dioxolane (EMD) were prepared from the corresponding cyclic vinyl acetals by catalytic isomerization of the double bond. The reaction of CKAs with different alcohols and diols was examined using trace of p-toluenesulfonic acid as a catalyst. For the monohydroxyl alcohols, cyclic ortho esters were formed by simple addition of the hydroxyl group toward CKAs with ethanol showing a much greater reactivity than iso-propanol. When 1,2- or 1,3-diols were used to react with the CKAs, we observed the isomerized cyclic ortho esters besides the simple addition products. Biocompatible polyols, that is, poly(2-hydroxyethyl acrylate) (PHEA) and poly(vinyl alcohol) (PVA) were then modified with CKAs, and the degree of substitution of the pendent ortho esters can be easily tuned by changing feed ratio. Both the small molecule ortho esters and the CKA-modified polymers demonstrate the pH-dependent hydrolysis profiles, which depend also on the chemical structure of the ortho esters as well as the polymer hydrophobicity. PMID:22176024

Cheng, Jing; Ji, Ran; Gao, Shi-Juan; Du, Fu-Sheng; Li, Zi-Chen

2012-01-01

203

Molecular assembly, interfacial rheology and foaming properties of oligofructose fatty acid esters.  

PubMed

Two major types of food-grade surfactants used to stabilize foams are proteins and low molecular weight (LMW) surfactants. Proteins lower the surface tension of interfaces and tend to unfold and stabilize the interface by the formation of a visco-elastic network, which leads to high surface moduli. In contrast, LMW surfactants lower the surface tension more than proteins, but do not form interfaces with a high modulus. Instead, they stabilize the interface through the Gibbs-Marangoni mechanism that relies on rapid diffusion of surfactants, when surface tension gradients develop as a result of deformations of the interface. A molecule than can lower the surface tension considerably, like a LMW surfactant, but also provide the interface with a high modulus, like a protein, would be an excellent foam stabilizer. In this article we will discuss molecules with those properties: oligofructose fatty acid esters, both in pure and mixed systems. First, we will address the synthesis and structural characterization of the esters. Next, we will address self-assembly and rheological properties of air/water interfaces stabilized by the esters. Subsequently, this paper will deal with mixed systems of mono-esters with either di-esters and lauric acid, or proteins. Then, the foaming functionality of the esters is discussed. PMID:24292507

van Kempen, Silvia E H J; Schols, Henk A; van der Linden, Erik; Sagis, Leonard M C

2014-01-01

204

Modelling the behavior of 5-aminolevulinic acid and its alkyl esters in a lipid bilayer  

NASA Astrophysics Data System (ADS)

5-Aminolevulinic acid (5ALA) and ester derivates thereof are used as prodrugs in photodynamic therapy (PDT). The behavior of 5ALA and three esters of 5ALA in a DPPC lipid bilayer is investigated. In particular, the methyl ester displays a very different free energy profile, where the highest barrier is located in the region with highest lipid density, while the others have their peak in the middle of the membrane, and also displays a considerably lower permeability coefficient than neutral 5ALA and the ethyl ester. The zwitterion of 5ALA has the highest permeability constant, but a significant free energy minimum in the polar head-group region renders an accumulation in this region.

Erdtman, Edvin; dos Santos, Daniel J. V. A.; Lfgren, Lennart; Eriksson, Leif A.

2008-09-01

205

Desorption of arsenic from clay and humic acid-coated clay by dissolved phosphate and silicate  

NASA Astrophysics Data System (ADS)

Arsenic (As) contaminated aquifers contain iron minerals and clays that strongly bind As at their surfaces. It was suggested that As mobilization is driven by natural organic matter (including fulvic acids (FA) and humic acids (HA)) present in the aquifers either via providing reducing equivalents for reductive dissolution of Fe(III) (hydr)oxides or via competitive desorption of As from the mineral surfaces. In the present study we quantified sorption of As(III) and As(V) to Ca 2+-homoionized illite (IL) and to kaolinite (Kao) as well as to HA-coated clays, i.e., illite-HA (IL-HA) and kaolinite-HA (Kao-HA) at neutral pH. Clay-HA complexes sorbed 28-50% more As than clay-only systems upon addition of 100 ?M As(III)/As(V) to 0.5 g of clay or HA-clay with Ca 2+ probably playing an important role for HA binding to the clay surface and As binding to the HA. When comparing sorption of As(V) and As(III) to clay and HA-clay complexes, As(V) sorption was generally higher by 15-32% than sorption of As(III) to the same complexes. IL and IL-HA sorbed 11-28% and 6-11% more As compared to Kao and Kao-HA, respectively. In a second step, we then followed desorption of As from Kao, Kao-HA, IL and IL-HA by 100 and 500 ?M phosphate or silicate both at high (0.41-0.77 ?mol As/g clay), and low (0.04 to 0.05 ?mol As/g clay) As loadings. Phosphate desorbed As to a larger extent than silicate regardless of the amount of As loaded to clay minerals, both in the presence and absence of HA, and both for illite and kaolinite. At high loadings of As, the desorption of both redox species of As from clay-HA complexes by phosphate/silicate ranged from 32 to 72% compared to 2-54% in clay only systems meaning that As was desorbed to a larger extent from HA-coated clays compared to clay only systems. When comparing As(III) desorption by phosphate/silicate to As(V) desorption in high As-loading systems, there was no clear trend for which As species is desorbed to a higher extent in the four clay systems meaning that both As species behave similarly regarding desorption from clay surfaces by phosphate/silicate. Similarly, no significant differences were found in high As-loading systems in the amount of As desorbed by phosphate/silicate when comparing Kao vs. IL and Kao-HA vs IL-HA systems meaning that both clay types behave similarly regarding desorption of As by phosphate/silicate. At low As loadings, up to 80% of As was desorbed by phosphate and silicate with no noticeable differences being observed between different As species, different types of clay, clay vs clay-HA or the type of desorbant (phosphate and silicate). The results of this study showed that HA sorption to Ca 2+-homoionized clay minerals can increase As binding to the clay although the As sorbed to the clay-HA is also released to a greater extent by competing ions such as phosphate and silicate. Desorption of As depended on the initial loadings of As onto the clay/clay-HA. Based on our results, the effect of humic substances on sorption of As and on desorption of As by phosphate and silicate has to be considered in order to fully understand and evaluate the environmental behavior of As in natural environments.

Sharma, Prasesh; Kappler, Andreas

2011-11-01

206

Adsorption of lutein from soybean oil on silicic acid I. Isotherms  

Microsoft Academic Search

Adsorption of lutein from crude soybean oil miscella on dispersed silicic acid resulted in three different Freundlich type\\u000a isotherms, depending on the amount of adsorbent used. Normally, changing the amount of adsorbent gives a new point on the\\u000a same isotherm. Further investigation of the lutein adsorption revealed that addition of 1% isopropanol to the hexane solvent\\u000a and deactivation of the

Andrew Proctor; Harry E. Snyder

1987-01-01

207

Proteosilica - mesoporous silicates densely filling amino acid and peptide assemblies in their nanoscale pores  

Microsoft Academic Search

In order to prepare protein-like structure in inorganic mesostructured framework, methodologies to densely fill assemblies of amino acids and peptides in mesoporous silica (Proteosilica) are proposed in this study. Surfactants having a peptide residue with hydrophobic chain at C-terminal and polar group at N-terminal were newly synthesized, and mesoporous silicates in both powder and film forms were successfully prepared with

K. Ariga; Q. Zhang; M. Niki; A. Okabe; T. Aida

2003-01-01

208

Effect of physical ageing on properties of PLA plasticized with oligomeric esters of lactic acid  

NASA Astrophysics Data System (ADS)

Two oligomeric esters of lactic acid with carboxyl or hydroxyl terminal groups were employed to plasticize polylactic acid. The miscibility of the blends as well as the mechanical, thermal and gas/vapour transport properties were tested as a function of plasticizer content and of physical ageing. A ductile PLA behavior was obtained with the addition of at least 20 wt% of both esters supplying an increase of elongation at break values higher than 400%. These blends retain their ductile feature also after ageing. Finally migration tests proved the compliance of these materials with the EU regulation for food contact plastics.

Castaldo, R.; Ambrogi, V.; Avella, M.; Avolio, R.; Carfagna, C.; Cocca, M.; Errico, M. E.; Gentile, G.

2014-05-01

209

Stability studies on methyl and ethyl fatty acid esters of sunflower seed oil  

SciTech Connect

Fatty acid esters, high in linoleic acid, were prepared and stored for long-term engine tests. Storage tests were undertaken to obtain data on optimal storage requirements and general stability characteristics. Samples were kept at three temperature levels (20 C, 30C and fluctuating around 50 C) for a 90-day period and were removed at regular intervals for chemical and physical analysis. The influence of air, temperature, light, TBHQ and contact with mild steel was evaluated by comparing the free fatty acid, peroxide, anisidine, ultraviolet absorption, viscosity and inducation periods. A statistical model was used to evaluate the data and to reduce the data points to comparable curves. Storage of esters in contact with air, especially at a temperature above 30 C, resulted in significant increases in peroxide, ultraviolet absorption, free fatty acid, viscosity and anisidine values. Exclusion of air retarded oxidation at all temperature levels. A direct relationship between viscosity increases and oxidation parameters was evident. Exposure to light caused a small increase in the oxidation parameters of esters stored at the highest temperature level. Addition of TBHQ prevented oxidation of samples stored under moderate conditions. Under unfavorable storage conditions the anti-oxidant was no longer effective. Mild steel had very little effect on the oxidation parameters. The anisidine values of samples stored at the highest temperature level were slightly increased. Methyl esters performed slightly better than ethyl esters during the storage test. The recommended guidelines for storage of fatty acid ester fuels are: (1) airtight containers should be used, (2) the storage temperature should be less than 30 C, (3) mild steel (rust free) containers may be used, and (4) TBHQ has a beneficial effect on oxidation stability. 13 references.

Du Plessis, L.M.; De Villiers, J.B.M.; Van der Walt, W.H.

1985-04-01

210

Fatty acids and their sucrose esters affect the properties of fish skin gelatin-based film  

Microsoft Academic Search

The effects of fatty acids (FA) [palmitic acid (PA) and stearic acid (SA)] and their sucrose esters (FASE) on the mechanical\\u000a properties, water vapor permeability (WVP), light transmission, and color of films from bigeye snapper and brownstripe red\\u000a snapper skin gelatins were investigated. Tensile strength (TS) of films generally decreased with the addition of FA (ppp<0.05). However, films containing FASE

Akkasit Jongjareonrak; Soottawat Benjakul; Wonnop Visessanguan; Munehiko Tanaka

2006-01-01

211

Conjugated linoleic acid modulation of phorbol ester-induced events in murine keratinocytes  

Microsoft Academic Search

Recent work in our lab has shown that the chemoprotective fatty acid, conjugated linoleic acid (CLA), inhibits phorbol ester\\u000a skin tumor promotion in mice. Because little is known about the deposition of CLA into tissues as well as its biological activity,\\u000a this study compared the incorporation and biological activity of CLA to linoleic acid (LA; 18:2, c9, c12) and arachidonic

Kai-Li Liu; Martha A. Belury

1997-01-01

212

Enzymatic preparation of polyethylene glycol esters of castor oil fatty acids and their surface-active properties  

Microsoft Academic Search

This study concerns the preparation and evaluation of nonionic surfactants prepared from polyethylene glycol (PEG) esters\\u000a of castor oil fatty acid, a source of hydroxy fatty acid. A lipase-catalyzed esterification reaction has been employed to\\u000a prepare PEG esters of hydroxy acid to overcome problems associated with chemical processes. Castor oil fatty acid (85% ricinoleic\\u000a acid) was mixed with PEG of

M. Ghosh; D. K. Bhattacharyya

1998-01-01

213

Cytotoxic evaluation of semisynthetic ester and amide derivatives of oleanolic acid.  

PubMed

Although a number of chemicals have been isolated from Lantana camara, only a few have been evaluated for their biological significance. As part of our drug discovery program for cytotoxic agents from Indian medicinal plants, roots of L. camara L. were chemically investigated, which resulted in the isolation and identification of a cytotoxic agent, oleanolic acid (1b) as a major constituent. Oleanolic acid was converted into six semi-synthetic ester (2-7) and seven amide (8-14) derivatives. The ester derivatives (2-7) showed 3-6 times more selective activity than 1b against the human ovarian cancer cell line (IGR-OV-1), while amide derivatives 8-14 showed 16-53 times more selective activity against the human lung cancer cell line (HOP-62). Structure activity relationship within the ester (2-7) and amide (8-14) derivatives are discussed. PMID:21121249

Gupta, Shikha; Kalani, Komal; Saxena, Mohit; Srivastava, Santosh K; Agrawal, Satyam K; Suri, Nitasha; Saxena, Ajit K

2010-10-01

214

Process for the generation of .alpha., .beta.-unsaturated carboxylic acids and esters using niobium catalyst  

DOEpatents

A process using a niobium catalyst includes the step of reacting an ester or carboxylic acid with oxygen and an alcohol in the presence a niobium catalyst to respectively produce an .alpha.,.beta.-unsaturated ester or carboxylic acid. Methanol may be used as the alcohol, and the ester or carboxylic acid may be passed over the niobium catalyst in a vapor stream containing oxygen and methanol. Alternatively, the process using a niobium catalyst may involve the step of reacting an ester and oxygen in the presence the niobium catalyst to produce an .alpha.,.beta.-unsaturated carboxylic acid. In this case the ester may be a methyl ester. In either case, niobium oxide may be used as the niobium catalyst with the niobium oxide being present on a support. The support may be an oxide selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide and mixtures thereof. The catalyst may be formed by reacting niobium fluoride with the oxide serving as the support. The niobium catalyst may contain elemental niobium within the range of 1 wt % to 70 wt %, and more preferably within the range of 10 wt % to 30 wt %. The process may be operated at a temperature from 150 to 450.degree. C. and preferably from 250 to 350.degree. C. The process may be operated at a pressure from 0.1 to 15 atm. absolute and preferably from 0.5-5 atm. absolute. The flow rate of reactants may be from 10 to 10,000 L/kg.sub.(cat) /h, and preferably from 100 to 1,000 L/kg.sub.(cat) /h.

Gogate, Makarand Ratnakav (Durham, NC); Spivey, James Jerome (Cary, NC); Zoeller, Joseph Robert (Kingsport, TN)

1999-01-01

215

The bioavailability and pharmacodynamics of different concentrations of omega-3 acid ethyl esters.  

PubMed

Omega-3 fatty acids have a long history of use as dietary supplements and more recently for therapeutic applications as prescription pharmaceuticals. Achieving a high concentration is critical for developing convenient, practical therapeutic formulations. The objective of the study was to explore the uptake and effects of different concentrations of omega-3 acid ethyl esters. Three different omega-3 concentrations were investigated in a clinical study with 101 subjects. All participants were dosed for 14 days with 5.1g per day of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) ethyl esters provided in three concentrations: 62.5%, 80% and 85% of total fatty acids. Key endpoints of the study were serum phospholipids and standard fasting lipid panels at day 14. Although administered the same quantity of omega-3 fatty acids, the patients taking the more concentrated formulations had higher levels of EPA/DHA in serum phospholipids and greater reductions in serum triglyceride and VLDL cholesterol levels. Total and non-HDL cholesterol were significantly reduced from baseline with all three formulations. In conclusion the concentration of omega-3 fatty acids of the formulations studied had independent effects on the uptake and effect outcomes during short-term administration. Very high concentrations of omega-3 acid ethyl esters (80%) appear to have higher uptake and are more potent for reducing triglycerides (TGs) and VLDL-cholesterol than formulations with lower concentrations. PMID:16806871

Bryhn, M; Hansteen, H; Schanche, T; Aakre, S E

2006-07-01

216

Synthesis and evaluation of odour-active methionyl esters of fatty acids via esterification and transesterification of butter oil.  

PubMed

Methionol-derived fatty acid esters were synthesised by both chemical and lipase catalysed esterification between fatty acids and methionol. Beneficial effects of both methods were compared qualitatively and quantitatively by GC-MS/GC-FID results. And the high acid and heat stability of our designed methionyl esters meet the requirement of the food industry. Most importantly, the sensory test showed that fatty acid carbon-chain length had an important effect on the flavour attributes of methionyl esters. Moreover, through Lipozyme TL IM-mediated transesterification, valuable methionol-derived esters were synthesised from the readily available natural material butter oil as the fatty acid source. The conversion of methionol and yield of each methionyl ester were also elucidated by GC-MS-FID. PMID:24128547

Li, Cheng; Sun, Jingcan; Fu, Caili; Yu, Bin; Liu, Shao Quan; Li, Tianhu; Huang, Dejian

2014-02-15

217

Amino Acid Derivatives, IV [1]: Synthesis and Antiviral Evaluation of New ?-Amino Acid Esters Bearing Methyl ?- d -Ribofuranoside Side Chain  

Microsoft Academic Search

Summary.Methyl 2,3-O-isopropylidene-?-d-ribofuranoside was synthesized and oxidized with HIO4 to afford the corresponding carboxylic acid. The latter was coupled with the appropriate acylated amino acids in the presence\\u000a of HOBt and DDC as coupling reagents to give the corresponding amides. The methyl acetate derivative was hydrolyzed with 2?N KOH\\/MeOH to the corresponding carboxylic acid, which was coupled with l-glycine methyl ester

Ibrahim A. I. Ali; Omar M. Ali; Adel A.-H. Abdel-Rahman

2007-01-01

218

Lipase-catalyzed esterification of unusual substrates: Synthesis of glucuronic acid and ascorbic acid (vitamin C) esters  

Microsoft Academic Search

The synthesis of n-butanol and cinnamic alcohol esters of glucuronic acid and the esterification of ascorbic acid (vitamin C) with phenylbutyric acid was performed with lipase from Candida antarctica B (CAL-B, SP435) in a mainly solid-phase system. Products were obtained in 15 to 22 % yield. Computer modelling based on the structure of CAL-B was used to elucidate the access

Ralf T. Otto; Uwe T. Bornscheuer; Holger Scheib; Jrgen Pleiss; Christoph Syldatk; Rolf D. Schmid

1998-01-01

219

Pretreatment of yellow grease for efficient production of fatty acid methyl esters  

Microsoft Academic Search

Biodiesel is a renewable fuel comprised of fatty acid methyl esters (FAME) derived from vegetable oils or animal fats. Comparisons between biodiesel and petroleum-based diesel have shown biodiesel to be effective in reducing exhaust emissions of carbon monoxide, hydrocarbons, particulate matter, and sulfur dioxide. While there are advantages of biodiesel over the traditional petroleum based diesel, biodiesel commercialization is limited

Walterio Diaz-Felix; Mark R. Riley; Werner Zimmt; Michael Kazz

2009-01-01

220

Immunomodulatory effect of caffeic acid phenethyl ester in Balb\\/c mice  

Microsoft Academic Search

Caffeic acid phenethyl ester (CAPE), an the active component of propolis, is known to have anticarcinogenic, antiviral and various biological activities; however, the effect of CAPE on the immunomodulatory activity in vivo remains unknown. We have investigated the effect of CAPE on the immune system in female Balb\\/c mice. CAPE (0, 5, 10, 20 mg\\/kg) was given to mice orally

Jae Hyun Park; Jong Kwon Lee; Hyung Soo Kim; Seung Tae Chung; Juno H. Eom; Kyung A. Kim; Se Jin Chung; Soon Young Paik; Hye Young Oh

2004-01-01

221

Amonia gas: an improved reagent for chemical ionization mass spectrometry of bile acid methyl ester acetates  

Microsoft Academic Search

The ammonia chemical ionization mass spectra of 28 methyl ester acetate derivatives of bile acids and related compounds have been determined by gas-liquid chromatography-mass spectrometry. Advantages of ammonia ionization over the previously studied isobutane ionization include a 130 to 270% enhancement in the sensitivity of base peak monitoring, and direct determination of molecular weight from the base peak (M +

B. R. DeMark; P. D. Klein

1981-01-01

222

Novel and Efficient One-Pot Synthesis of (Aminophenyl)carbamic Acid Esters  

Microsoft Academic Search

A novel and efficient protocol is developed for the synthesis of various (aminophenyl)carbamic acid esters from the reduction and condensation of nitrophenyl isocyanate derivatives. The reaction takes place in various hydroxy derivatives such as alcohols or phenols under a hydrogen atmosphere using Raney nickel as catalyst. Products are obtained by a convenient onepot synthesis with excellent yields and short reaction

Antonio Garofalo; Laurence Goossens; Perrine Six; Nicolas Lebegue; Patrick Depreux

2011-01-01

223

Estimation of the environmental contamination by phthalic acid esters leaching from household wastes  

Microsoft Academic Search

Phthalic acid esters (PAE) have been used as plasticizers in many products. Here we estimate the contaminating potential of PAE codisposed with domestic wastes. In order to determine the maximum threat to the environment, we analysed several fractions of different household wastes. A maximum of 2.6% of di-(2-ethylhexyl) phthalate (DEHP) was measured in compound materials. More than 90% of all

M. J. Bauer; R. Herrmann

1997-01-01

224

SEPARATION OF T-MAZ ETHOXYLATED SORBITAN FATTY ACID ESTERS BY SUPERCRITICAL FLUID CHROMATOGRAPHY  

EPA Science Inventory

The application of supercritical fluid chromatography (SFC) to the analysis of T-MAZ ethoxylated sorbitan fatty acid esters is described. FC separation methods utilize a density programming technique and a 50 um I.D. capillary column. his work demonstrates that capillary column S...

225

Use of vegetable oils and fatty acid methyl esters in the production of spherical activated carbons  

Microsoft Academic Search

The possibility of using vegetable oils, i.e., rapeseed oil, soybean oil, linseed oil, tung oil, castor oil and dehydroxylated castor oil, and the fatty acid methyl esters (FAMEs) obtained from them, for the agglomeration of bituminous coals was investigated. Both vegetable oils and FAMEs were found to be suitable bridging liquids for the production of spherical agglomerates-precursor of spherical activated

S Gryglewicz; K Grabas; G Gryglewicz

2000-01-01

226

Performance and Emission Analysis of Diesel engine using of Single Composition Fatty Acid Methyl Esters  

Microsoft Academic Search

Biodiesel is also called as Fatty acid Methyl ester. It is an alternative fuel for diesel engines that can be manufactured from vegetable oils, animal fats and used cooking oils. It offers many advantages such as it is renewable, energy efficient, nontoxic, sulfur free and biodegradable, and also it usually takes cleaner combustion and reduces global warming gas emissions from

T. Hari; K. Hema Chandra Reddy; M. Muralidhara Rao

227

Novel sustained-release dosage forms of proteins using polyglycerol esters of fatty acids  

Microsoft Academic Search

In order to develop a novel delivery system for proteins based on polyglycerol esters of fatty acids (PGEFs), we studied a model system using interferon-? (IFN-?) as the test protein. A cylindrical matrix was prepared by a heat extrusion technique using a lyophilized powder of the protein and 11 different types of synthetic PGEFs, which varied in degree of glycerol

Yutaka Yamagata; Katsumi Iga; Yasuaki Ogawa

2000-01-01

228

Oxidative transformation of a naturally occurring okadaic acid diol ester by the diatom Thalassiosira weissflogii  

Microsoft Academic Search

The diarrhetic shellfish poisoning (DSP) toxin okadaic acid (1) is found in extracts of the dinoflagellate Prorocentrum lima together with a suite of diol esters such as 2. When 2 was added to the culture medium of the centric diatom Thalassiosira weissflogii, it was transformed into a range of products within three days. Three of these products, 3, 4 and

Tingmo Hu; Ian Burton; Jonathan M. Curtis; Michael A. Quilliam; John A. Walter; Anthony J. Windust; Jeffrey L. C. Wright

1999-01-01

229

Nonenzymic browning. 3. Browning reactions during heating of fish oil fatty acid esters with protein  

Microsoft Academic Search

Summary During heating of mixtures of methyl esters of polyunsaturated fish oil fatty acids and albumen under simulated conditions of roasting and frying of fish, peroxides present in the lipidic fraction are rapidly decomposed and form both liposoluble and insoluble brown pigments with free amino groups of albumen. Small amounts of lipids in the mixture have already great effect on

J. Pokorn; B. A. El-Zeany; G. Jan?ek

1973-01-01

230

Syntheses of fluorooxindole and 2-fluoro-2-arylacetic acid derivatives from diethyl 2-fluoromalonate ester  

PubMed Central

Summary Diethyl 2-fluoromalonate ester is utilised as a building block for the synthesis of 2-fluoro-2-arylacetic acid and fluorooxindole derivatives by a strategy involving nucleophilic aromatic substitution reactions with ortho-fluoronitrobenzene substrates followed by decarboxylation, esterification and reductive cyclisation processes.

Harsanyi, Antal; Yufit, Dmitri S; Howard, Judith AK

2014-01-01

231

Abiotic degradation of four phthalic acid esters in aqueous phase under natural sunlight irradiation  

Microsoft Academic Search

Abiotic degradability of four phthalic acid esters (PAEs) in the aquatic phase was evaluated over a wide pH range 59. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to

Ruttapol Lertsirisopon; Satoshi Soda; Kazunari Sei; Michihiko Ike

2009-01-01

232

Assessment of the hydrolysis process for the determination of okadaic acid-group toxin ester: presence of okadaic acid 7-O-acyl-ester derivates in Spanish shellfish.  

PubMed

The contamination of different types of shellfish by okadaic acid (OA)-group toxin esters is an important problem that presents serious risk for human health. During previous investigations carried out in our laboratory by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS), the occurrence of a high percentage of esters in relation to the total OA equivalents has been observed in several shellfish species. The determination of these kinds of toxins using LC/MS or other chemical methods requires a hydrolysis step in order to convert the sterified compounds into the parent toxins, OA, dinophysistoxins-1 (DTX-1) and dinophysistoxins-2 (DTX-2). Most of the hydrolysis procedures are based on an alkaline hydrolysis reaction. However, despite hydrolysis being a critical step within the analysis, it has not been studied in depth up to now. The present paper reports the results obtained after evaluating the hydrolysis process of an esterified form of OA by using a standard of 7-O-acyl ester with palmitoyl as the fatty acid (palOA). Investigations were focused on checking the effectiveness of the hydrolysis for palOA using methanol as solvent standard and matrices matched standards. From the results obtained, no matrix influence on the hydrolysis process was observed and the quantity of palOA converted into OA was always above 80%. The analyses of different Spanish shellfish samples showed percentages of palOA in relation to the total OA esters ranging from 27% to 90%, depending on the shellfish specie. PMID:18243269

Villar-Gonzlez, A; Rodrguez-Velasco, M L; Ben-Gigirey, B; Yasumoto, T; Botana, L M

2008-04-01

233

Synthetic detergents from animal fats. V. Esters from alpha-sulfonated fatty acids and sodium isethionate  

Microsoft Academic Search

SummaryDisodium 2-sulfoethyl ?-sulfopalmitate, disodium 2-sulfoethyl ?-sulfostearate, and disodium 2-sulfoethyl ?-sulfobehenate were\\u000a prepared by esterification of the corresponding ?-sulfonated acid with sodium isethionate. Disodium 1-methyl-2-sulfoethyl\\u000a ?-sulfostearate was made from sodium 2-hydroxypropanesulfonate. The esters were found to be readily soluble surface-active\\u000a agents and detergents, very responsive to building with inorganic phosphates and sulfates.\\u000a \\u000a Compared to sodium 2-sulfoethyl oleate the esters were readily

J. K. Weil; R. G. BISTLINE JR; A. J. Stirton

1955-01-01

234

Antimicrobial effects of esters and amides of 3-(5-nitro-2-furyl)acrylic acid.  

PubMed

The effect of 18 newly synthesized esters and amides of 3-(5-nitro-2-furyl)acrylic acid on bacteria (Escherichia coli, Staphylococcus aureus), yeasts (Saccharomyces cerevisiae, Candida albicans), molds (Aspergillus niger, Penicillium cyclopium, Rhizopus oryzae) and algae (Chlorella pyrenoidosa, Euglena gracilis, Scenedesmus obliquus) was investigated. The MIC values revealed antimycotic, antialgal and antibacterial activity of the studied derivatives. The antimycotic activity was found to decrease with increasing the length of the alkyl chain of esters and after introduction of amino nitrogen into the furylethylene backbone. The inhibitory effect on growth is caused by blocking bioenergetic processes, glycolysis in particular. PMID:6714854

Kellov, G; Sturdk, E; Stibrnyi, L; Drobnica, L; Augustn, J

1984-01-01

235

Isolation of natural arachidonic acid as its methyl ester  

Microsoft Academic Search

SummaryFresh beef suprarenal glands were ground and extracted thoroughly with alcohol and then with ethyl ether. After removal of\\u000a solvent the total lipid residue was saponified, and the fatty acids were recovered by extraction. The less unsaturated acids\\u000a were removed by crystallization from acetone at ?40C. At this stage the filtrate contained essentially all the arachidonic\\u000a acid originally present in

S. F. Herb; R. W. Riemenschneider; Jeanette Donaldson

1951-01-01

236

Preparation of ?-hydroxynonanoic acid and its ester derivatives  

Microsoft Academic Search

Methyl ricinoleate was ozonized in methanol or in acetic acid and the intermediate hydroperoxides were reduced electrochemically\\u000a on Pb-cathode to give 9-hydroxynonanoic acid 1 in high yields. The acid 1 was also prepared by direct castor oil ozonolysis in methanol followed by sodium borohydride reduction of the intermediate\\u000a hydroperoxides. The cost of the electricity for the electroreduction was at least

Jozef Kula; Krzysztof Smigielski; Thuat B. Quang; Iwona Grzelak; Magdalena Sikora

1999-01-01

237

N-( p-Ethynylbenzoyl) derivatives of amino acid and dipeptide methyl esters Synthesis and structural study  

Microsoft Academic Search

A series of N-(p-ethynylbenzoyl) derivatives (14) of the amino acids glycine and l-alanine as well as the dipeptides glycylglycine and l-alanylglycine has been synthesized via a two-step reaction sequence including the reaction of an appropriate N-(p-bromobenzoyl) precursor with trimethylsilylacetylene followed by deprotection of the trimethylsilyl protecting group, respectively. X-ray crystal structures of the amino acid and dipeptide methyl esters 14

Frank Eimann; Edwin Weber

2011-01-01

238

Branched chain amino acid metabolism in the biosynthesis of Lycopersicon pennellii glucose esters  

Microsoft Academic Search

Lycopersicon pennellii Corr. (D'Arcy) an insect-resistant, wild tomato possesses high densities of glandular trichomes which exude a mixture of 2,3,4-tri-O-acylated glucose esters that function as a physical impediment and feeding deterrent to small arthropod pests. The acyl moieties are branched C and C acids, and branched and straight chain C, C, and C acids. The structure of the branched acyl

D. S. Walters; J. C. Steffens

1990-01-01

239

Long chain cellulose esters with very low DS obtained with non-acidic catalysts  

Microsoft Academic Search

Long-chain cellulose esters with very low degree of substitution (DS<0.3), useful for specialty applications, were obtained\\u000a by reaction with fatty acids (FAs) without solvent for cellulose. Non-acidic catalysts such as FA salts were used to limit\\u000a the cellulose degradation when subjected to reaction at high temperatures. The surfactant character of this type of molecules\\u000a was employed to create an emulsion

J. Peydecastaing; S. Girardeau; C. Vaca-Garcia; M. E. Borredon

2006-01-01

240

[Conservative motif CMLD in silicic acid transport proteins of diatom algae].  

PubMed

Sequencing of fragments of genes coding for silicic acid transport (SIT) proteins of diatoms of evolutionary distant classes (centric Chaetoceros muelleri Lemmermann, pennate araphid Synedra acus Ktzing, pennate raphid Phaeodactylum tricornutum Bohlin, and pennate with keeled raphe system Cylindrotheca fusiformis Reimann et Lewin), revealed the presence in these proteins of a conservative amino acid motif CMLD. Hydropathy profiles suggest that CMLD occupies a position between two transmembrane strands which do not contain lysine and arginine residues. The two strands are good candidates for the role of the channel along which transport of silicic acid occurs. CMLD is a rare motif. Diatoms are known to need Zn2+ for the incorporation of silica. Presumably, CMLD is the site of Zn2+ binding of SITs. We found that the growth of diatoms is inhibited by a negatively charged alkylating reagent 5-(2-iodoacetamidoethyl)aminonaphtalene-1-sulfonic acid which cannot penetrate through the cell membrane. Cysteine of CMLD can be a target of this reagent. Synthetic peptide NCMLDY forms a complex with Zn2+, as revealed by the fact that the ion considerably reduces the rate of alkylation of the peptide. PMID:15856954

Shcherbakova, T A; Masiukova, Iu A; Safonova, T A; Petrova, D P; Vereshchagin, A L; Minaeva, T V; Adel'shin, R V; Tribo?, T I; Stonik, I V; A?zda?cher, N A; Kozlov, M V; Likhoshva?, E V; Grachev, M A

2005-01-01

241

Structure-activity considerations and in vitro approaches to assess the genotoxicity of 19 methane-, benzene- and toluenesulfonic acid esters.  

PubMed

Sulfonic acid esters are considered as potentially alkylating agents that may exert genotoxic effects in bacterial and mammalian cell systems. One possible source of human exposure stems from drug synthesis when the salt-forming agents methanesulfonic acid, benzenesulfonic acid or p-toluenesulfonic acid are used together with alcoholic solvents such as methanol, ethanol and propanol. In this study computer-assisted structural considerations and in vitro approaches (Ames mutagenicity test using Salmonella typhimurium strains TA98 and TA100, and the micronucleus test using L5178Y mouse lymphoma cells) were used to assess the genotoxic properties of 19 sulfonic esters. While all esters may be principally active as genotoxicants based on the presence of the sulfonate moiety, the statistical correlative multiple computer automated structure evaluation (MCASE) system (MC4PC version 1.0) using the Ames mutagenicity A2I module (version 1.54), rank-ordered the activity of the benzenesulfonic acid esters in the Ames test negligible due to an inactivating modulator and a deactivating fragment, whereas the methane- and toluenesulfonic acid esters were predicted to be positive in this test. In the Ames test, with the exception of the p-toluenesulfonic acid ethyl and iso-butyl esters, all compounds came out positive in Salmonella strain TA100. Methanesulfonic iso-propyl, sec-butyl and benzenesulfonic acid iso-propyl ester also showed mutagenic potential in strain TA98. In general, differences between results seen in Ames tests performed with or without metabolic activation were rather small. In L5178Y mouse lymphoma cells, benzenesulfonic acid n- and iso-butyl ester and p-toluenesulfonic acid iso-butyl ester did not increase the number of cells containing micronuclei. The other esters were positive in this micronucleus test; however, methanesulfonic acid iso-butyl ester was found to be only weakly positive at excessively cytotoxic concentrations. These compounds were generally found to be more potent with regard to micronucleus induction when tested without metabolic activation (20 h treatment). In conclusion, the iso-propyl esters of the three sulfonic acids under study were found to be the strongest mutagens, either when tested in the Ames test or the micronucleus assay, whereas p-toluenesulfonic acid iso-butyl ester was the only compound shown to be devoid of a genotoxic potential in both tests. PMID:15725602

Glowienke, Susanne; Frieauff, Wilfried; Allmendinger, Thomas; Martus, Hans-Joerg; Suter, Willi; Mueller, Lutz

2005-03-01

242

Tribological study of a highly hydrolytically stable phenylboronic acid ester containing benzothiazolyl in mineral oil  

NASA Astrophysics Data System (ADS)

A novel long chain alkyl phenylboronic acid ester containing heterocyclic compound, bis (1-(benzothiazol-2-ylthio) propan-2-yl)-4-dodecylphenylboronic acid ester (DBBMT), was synthesized and characterized. The hydrolytic stability of the DBBMT was evaluated and the results show that DBBMT is of outstanding hydrolytic stability compared with normal borate esters, which indicates that the designed molecular structure, by introducing benzene ring to conjugate with the electron-deficient boron and the benzothiazole as a hinder group, is effective on obtaining a hydrolytically stable long chain alkyl phenylboronic acid ester. The tribological properties of DBBMT and ZDDP in mineral base oil were evaluated using a four-ball tribometer, which suggests that the DBBMT possesses comprehensive tribological properties and could be a potential candidate for the replacement of ZDDP. Furthermore, in order to understand the tribological behaviors, the worn surface was analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectroscopy. The results indicate that the elements S, B, O and Fe perform complicated tribochemical reactions to form the compact tribological film composed of B2O3, FeS, Fe3O4 and FeSO4.

Li, Zhipeng; Li, Xiufeng; Zhang, Yawen; Ren, Tianhui; Zhao, Yidong; Zeng, Xiangqiong; van der Heide, E.

2014-07-01

243

Citric acid esters from fruit of Lonicera caerulea  

Microsoft Academic Search

Compound (I) could be formed from the corresponding acid by methylation with diazomethane. The native nature of (I)was confirmed by its isolation from the initial unmethylated fraction after the elimination of citric acid from it with the use of AV-17 ion-exchange resin. The isolation of 7-oxologanin from plants of the genus Lonicera has not been reported previously.

E. V. Anikina; A. L. Vereshchagin; A. I. Syrchina; F. Larin; A. A. Semenov

1988-01-01

244

Synthesis, characterisation and biological evaluation of N-(ferrocenyl)naphthoyl amino acid esters as anticancer agents.  

PubMed

A series of N-(ferrocenyl)naphthoyl amino acid esters 5-18 has been prepared by coupling ferrocenyl naphthoic acids 3-4 to alpha-amino acids and linear amino acids in the presence of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and 1-hydroxybenzotriazole (HOBt). The compounds were fully characterised by a range of NMR spectroscopic techniques, UV-Vis spectroscopy, mass spectrometry and cyclic voltammetry. X-ray crystallographic studies of the intermediate compounds 1-2 were also performed. Biological evaluation of the intermediates 1-2 and N-(ferrocenyl)naphthoyl amino acid esters 5-18 was performed in the H1299 non-small cell lung cancer (NSCLC) cell line and the Sk-Mel-28 metastatic melanoma cell line. The intermediates 1-2 failed to produce an effect in either cell line. Compounds 5-18 exhibited a strong anti-proliferative effect in the H1299 cell line, whilst the Sk-Mel-28 cells were slightly more resistant to these compounds. N-(6-ferrocenyl-2-naphthoyl)-gamma-aminobutyric acid ethyl ester 17 shows a particularly high activity in both the H1299 cell line (IC(50) = 0.62 +/- 0.07 microM) and the Sk-Mel-28 cell line (IC(50) = 1.41 +/- 0.04 microM). PMID:20680224

Mooney, Aine; Corry, Alan J; N Ruairc, Cliodhna; Mahgoub, Thamir; O'Sullivan, Dermot; O'Donovan, Norma; Crown, John; Varughese, Sunil; Draper, Sylvia M; Rai, Dilip K; Kenny, Peter T M

2010-09-21

245

Structural and spectroscopic studies of new o-, m- and p-nitrobenzyl esters of lasalocid acid  

NASA Astrophysics Data System (ADS)

New o-, m- and p-nitrobenzyl esters of lasalocid ( o-ELAS, m-ELAS and p-ELAS) have been synthesised and studied by X-ray, 1H, 13C NMR, FT-IR, UV-Vis, fluorescence as well as PM5 semiempirical methods. The crystal structure of o-ELAS is stabilized by three intramolecular hydrogen bonds in which the ketone is not engaged. The FT-IR spectra of o-ELAS, m-ELAS and p-ELAS in the chloroform and acetonitrile solutions indicate that in these solvents other structures are realized in which the ketone group is hydrogen bonded. In the solution the hydrogen bonds in which the carbonyl ester groups are involved becomes slightly weaker and partially dissociated. The dissociation of these hydrogen bonds increases with increasing solvent polarity. The structures of the o-, m- and p-nitrobenzyl esters of lasalocid acid are discussed in detail.

Huczy?ski, Adam; Pospieszny, Tomasz; Wawrzyn, Rafa?; Ratajczak-Sitarz, Ma?gorzata; Katrusiak, Andrzej; Brzezinski, Bogumil; Bartl, Franz

2008-04-01

246

40 CFR 721.1731 - Poly(oxy-1,2-ethanediyl), α-methyl--hydroxy, ester with boric acid (H3BO3).  

Code of Federal Regulations, 2013 CFR

...methyl--hydroxy, ester with boric acid (H3BO3). 721.1731 Section...α-methyl--hydroxy, ester with boric acid (H3 BO3 ). (a) Chemical...α-methyl--hydroxy, ester with boric acid (H3 BO3 ) (PMN...

2013-07-01

247

40 CFR 721.1730 - Poly(oxy-1,2-ethanediyl), α-butyl--hydroxy, ester with boric acid (H3BO3).  

Code of Federal Regulations, 2010 CFR

...butyl--hydroxy, ester with boric acid (H3BO3). 721.1730 Section...α-butyl--hydroxy, ester with boric acid (H3BO3). (a) Chemical substance...α-butyl--hydroxy, ester with boric acid (H3 BO3 ) (PMN...

2010-07-01

248

40 CFR 721.1730 - Poly(oxy-1,2-ethanediyl), α-butyl--hydroxy, ester with boric acid (H3BO3).  

Code of Federal Regulations, 2010 CFR

...butyl--hydroxy, ester with boric acid (H3BO3). 721.1730 Section...α-butyl--hydroxy, ester with boric acid (H3BO3). (a) Chemical substance...α-butyl--hydroxy, ester with boric acid (H3 BO3 ) (PMN...

2009-07-01

249

Synthesis of acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters  

DOEpatents

A process of preparing an acid addition salt of delta-aminolevulinc acid comprising: a) dissolving a lower alkyl 5-bromolevulinate and hexamethylenetetramine in a solvent selected from the group consisting of water, ethyl acetate, chloroform, acetone, ethanol, tetrahydrofuran and acetonitrile, to form a quaternary ammonium salt of the lower alkyl 5-bromolevulinate; and b) hydrolyzing the quaternary ammonium salt with an inorganic acid to form an acid addition salt of delta-aminolevulinic acid.

Moens, Luc (Lakewood, CO)

2003-06-24

250

A new, direct analytical method using LC-MS/MS for fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD esters) in edible oils.  

PubMed

A new, direct analytical method for the determination of 3-chloro-1,2-propanediol fatty acid esters (3-MCPD esters) was developed. The targeted 3-MCPD esters included five types of monoester and 25 [corrected] types of diester. Samples (oils and fats) were dissolved in a mixture of tert-butyl methyl ether and ethyl acetate (4:1), purified using two solid-phase extraction (SPE) cartridges (C(18) and silica), then analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Five monoesters and five diesters with the same fatty acid group could be separated and quantified. Pairs of 3-MCPD diesters carrying the same two different fatty acid groups, but at reversed positions (sn-1 and sn-2), could not be separated and so were expressed as a sum of both compounds. The limits of quantification (LOQs) were estimated to be between 0.02 to 0.08 mg kg(-1), depending on the types of 3-MCPD ester. Repeatability expressed as relative standard deviation (RSD(r)%) varied from 5.5% to 25.5%. The new method was shown to be applicable to various commercial edible oils and showed levels of 3-MCPD esters varying from 0.58 to 25.35 mg kg(-1). The levels of mono- and diesters ranged from 0.10 to 0.69 mg kg(-1) and from 0.06 to 16 mg kg(-1), respectively. PMID:22909228

Yamazaki, K; Ogiso, M; Isagawa, S; Urushiyama, T; Ukena, T; Kibune, N

2013-01-01

251

Antioxidant properties of the fatty alcohol esters of gallic acid  

Microsoft Academic Search

Summary and ConclusionsThe antioxidant properties of octyl, dodecyl, tetradecyl, hexadecyl, and octadecyl gallates in lard substrate were determined\\u000a by the active oxygen method. The order of their effectiveness was about the same as that of the more active antioxidants,\\u000a nordihydroguariaretic acid and gallic acid, that have been reported. The carry-over of the antioxidant properties into baked\\u000a goods was determined by

Steward G. Morris; Lillian A. Kraekel; Dorothy Hammer; J. S. Myers; R. W. Riemenschneider

1947-01-01

252

Effects of metadoxine on cellular formation of fatty acid ethyl esters in ethanol treated rats.  

PubMed

Free fatty acids (FFA) and fatty acid ethyl esters (FAEE) were extracted from different organs of rats administered ethanol, which was found to have induced FAEE formation, which reached its highest levels in the heart, followed by kidney, brain and liver; the ethanol administration resulted also in a marked increase of total FFA content, particularly in brain, kidney, heart and liver. Pretreatment of animals with Metadoxine one hour before ethanol administration inhibited significantly both FAEE and FFA accumulation in all organs examined. These effects were concomitant with the decreased levels of ethanol in blood found in alcohol-intoxicated rats pretreated with Metadoxine. Our results point to the role of fatty acid ethyl esters as possible mediators in the production of alcohol-dependent syndromes, especially in organs lacking oxidative pathways. Administration of Metadoxine, through an increment in alcohol metabolism and turnover, greatly reduces this metabolic abnormality, warranting its potential usefulness as a pharmacological tool in alcoholism management. PMID:8867649

Calabrese, V; Calderone, A; Ragusa, N; Rizza, V

1995-01-01

253

A new CO 2 disposal process via artificial weathering of calcium silicate accelerated by acetic acid  

Microsoft Academic Search

A new disposal process for anthropogenic CO2 via an artificially accelerated weathering reaction is proposed to counteract global warming. The process is essentially composed of the following two steps:(1)CaSiO3+2CH3COOH?Ca2++2CH3COO?+H2O+SiO2(2)Ca2++2CH3COO?+CO2+H2O?CaCO3?+2CH3COOHStep (1) is the extraction of calcium ions by acetic acid from calcium silicate, for example, wollastonite rocks. Step (2) is the deposition of calcium carbonate from the solution of calcium ions

M. Kakizawa; A. Yamasaki; Y. Yanagisawa

2001-01-01

254

Novel surface-active oligofructose fatty acid mono-esters by enzymatic esterification.  

PubMed

This article describes the synthesis of a series of oligofructose monoesters with fatty acids of different chain length (C8, C12, C16 and C18) to obtain food-grade surfactants with a range of amphiphilicity. Reactions were performed in a mixture of DMSO/Bu(t)OH (10/90 v/v) at 60C and catalysed by immobilised Candida antarctica lipase B. MALDI-TOF-MS analysis showed that the crude reaction products were mixtures of unmodified oligofructose and mostly mono-esters. The conversion into mono-esters increased with the length of the fatty acid chain, reflecting the specificity of the lipase towards more lipophilic substrates. Reverse phase solid phase extraction was used to fractionate the products, which lead to sufficient purity (>93%) of the fatty acid esters for functionality testing. It was shown that derivatives of longer (C16 and C18) fatty acids were more efficient in lowering surface tension and gave a much higher dilatational modulus than derivatives of the shorter (C8 and C12) fatty acids. PMID:23411321

van Kempen, Silvia E H J; Boeriu, Carmen G; Schols, Henk A; de Waard, Pieter; van der Linden, Erik; Sagis, Leonard M C

2013-06-01

255

Squaric acid and esters: analysis for contaminants and stability in solvents.  

PubMed

Two squaric acid diesters, squaric acid diethyl ester (SADEE) and squaric acid dibutyl ester (SADBE), have been suggested as replacements for 2,4-dinitrochlorobenzene in the treatment of alopecia areata and alopecia totalis. We synthesized these squaric acid diesters and examined them for the presence of carcinogenic contaminants, hexachlorobutadiene and tetrachloro-2-cyclobutene-1-one, by gas chromatography-mass spectrometry (GC-MS). The stability of SADBE to hydrolysis by water in acetone, butanol, isopropanol, and absorbent ointment with and without molecular sieves was examined. The stability of SADEE in ethanol and acetone, with and without molecular sieves, was also studied. Hydrolysis products were detected by their formation of a colored complex with ferric chloride. This complex absorbs in the visual range at 480 nm, thus affording a convenient method for determination of the concentration of free squaric acid in a solution. No contaminants were found by positive or negative ion detection in our GC-MS system. At the end of 3 weeks the extent of hydrolysis was greater in alcohols than in acetone when 10 and 100 molar excess of water were added to the solutions. In the presence of molecular sieves, hydrolysis was reduced even at 100 molar excess of added water in alcohol ar acetone. However, under storage conditions without sieves, acetone solutions and alcohol solutions were equally stable over a period of 2 months. Molecular sieves reduce hydrolysis of squarate esters in the presence of a large molar excess of water, regardless of solvent. PMID:4044949

Wilkerson, M G; Henkin, J; Wilkin, J K; Smith, R G

1985-08-01

256

Comparison between the insulinotropic potential of ten new esters of succinic acid.  

PubMed

Selected esters of succinic acid are currently under investigation as insulinotropic tools for the treatment of non-insulin-dependent diabetes mellitus. The aim of the present study was to investigate, in isolated rat pancreatic islets, the insulin secretory response to ten novel esters of succinic acid. According to six different methods of comparison, the following hierarchy in insulinotropic potential was established: 4-tert-butyl-succinate < or = glycerol-1,2-dimethylsuccinate-3-hydrogenosuccinate < or = threitol-3-succinoyl-1,2,4-trimethylsuccinate < or = ethanediol-1,2-diethylsuccinate < or = glycerol-1,2-dimethylsuccinate < or = glycerol-3-hydroxy-1,2-dimethylsuccinate < or = arabitol-5-hydroxy-1,2,3,4-tetramethylsuccinate < or = threitol-1,2,4-trimethylsuccinate < or = ethanediol-1,2-dimethylsuccinate < propanediol-1,2-dimethylsuccinate. There was a close correlation (r = 0.823) between the insulinotropic potential and the minimal effective concentration, which ranged between the extreme values of 10 microM and 2.5 mM. In the presence of the esters, the concentration-response relationship for glucose-stimulated insulin release was changed from its typically sigmoidal shape to a hyperbolic pattern, with most agents enhancing insulin output at a low hexose concentration (2.8 mM) but failing to do so at a high glucose level (16.7 mM). Highly potent insulinotropic esters have several advantages over other antidiabetic agents in clinical use. PMID:9570452

Ladrire, L; Laghmich, A; Malaisse-Lagae, F; Dannacher, H; Bjrkling, F; Malaisse, W J

1998-02-26

257

The adjuvant activity of fatty acid esters. The role of acyl chain length and degree of saturation.  

PubMed Central

Water-in-oil emulsions of metabolizable fatty acid esters, with the non-toxic surfactant Pluronic L122 as emulsifying agent, potentiated the humoral response to bovine serum albumin and staphylococcal toxoid in the mouse. Adjuvant activity was increased by changing the chemical nature of the esters as follows: (i) using a series of ethyl esters, adjuvant activity appeared when the acyl chain length of the fatty acid component was 16 or greater; (ii) isobutyl and isopropyl esters of palmitic acid (C16:0) were superior to ethyl; (iii) the ethyl esters of oleic (C18:1) and linoleic (C18:2) acids were better than stearic (C18:0). Since emulsions prepared with longer chain saturated esters are very viscous or solid at room temperature, and unsaturated esters are chemically reactive, emulsions were prepared with differing proportions of ethyl caprate (C10:0) and butyl stearate. At a ratio of 9:1 the emulsions possessed the low viscosity of ethyl caprate, but gained the adjuvant activity of butyl stearate. 125I-labelled BSA was retained in the footpad to a significantly greater extent than with a caprate emulsion, but reasons are given for believing that slow release of antigen is not the only mechanism of adjuvant activity. The ester emulsions caused more acute but less chronic local inflammation (footpad swelling) than Freund's incomplete adjuvant.

Bomford, R

1981-01-01

258

The adjuvant activity of fatty acid esters. The role of acyl chain length and degree of saturation.  

PubMed

Water-in-oil emulsions of metabolizable fatty acid esters, with the non-toxic surfactant Pluronic L122 as emulsifying agent, potentiated the humoral response to bovine serum albumin and staphylococcal toxoid in the mouse. Adjuvant activity was increased by changing the chemical nature of the esters as follows: (i) using a series of ethyl esters, adjuvant activity appeared when the acyl chain length of the fatty acid component was 16 or greater; (ii) isobutyl and isopropyl esters of palmitic acid (C16:0) were superior to ethyl; (iii) the ethyl esters of oleic (C18:1) and linoleic (C18:2) acids were better than stearic (C18:0). Since emulsions prepared with longer chain saturated esters are very viscous or solid at room temperature, and unsaturated esters are chemically reactive, emulsions were prepared with differing proportions of ethyl caprate (C10:0) and butyl stearate. At a ratio of 9:1 the emulsions possessed the low viscosity of ethyl caprate, but gained the adjuvant activity of butyl stearate. 125I-labelled BSA was retained in the footpad to a significantly greater extent than with a caprate emulsion, but reasons are given for believing that slow release of antigen is not the only mechanism of adjuvant activity. The ester emulsions caused more acute but less chronic local inflammation (footpad swelling) than Freund's incomplete adjuvant. PMID:7275184

Bomford, R

1981-09-01

259

Thermochemistry of C-O, (CO)-O, and (CO)-C bond breaking in fatty acid methyl esters  

SciTech Connect

Density functional theory quantum chemical calculations corrected with empirical atomic increments have been used to examine C-O, (CO)-O, and (CO)-C bond scission enthalpies in gas-phase fatty acid methyl esters (FAMEs) present in biodiesel derived from rapeseed oil methyl ester and soybean oil methyl ester. Mechanistic information, currently not available elsewhere for these large species, is obtained based on thermochemical considerations and compared to thermochemical considerations reported for methyl butanoate, a small methyl ester sometimes used as a model for FAMEs. These results are compared to previously reported C-C and C-H bond scissions in these FAMEs, derived using this same protocol. (author)

Osmont, Antoine; Yahyaoui, Mohammed; Catoire, Laurent; Goekalp, Iskender [ICARE-CNRS and University of Orleans, 1C, avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Swihart, Mark T. [Department of Chemical and Biological Engineering, University at Buffalo (SUNY), Buffalo, NY 14260-4200 (United States)

2008-10-15

260

The action of tetra-n-propyldiborane on n-butyl vinyl ether and esters of allyboric and allylthioboric acids  

Microsoft Academic Search

1.When tetra-n-propyldiborane acts on n-butyl vinyl ether, di-n-propyl-(2-n-butoxyethyl)boron is formed, which is converted at room temperature with evolution of ethylene to the n-butyl ester of di-n-propylboric acid.2.Tetra-n-propyldiborane adds to esters of allyl- and allylthioboric acid with the formation of unstable din-propyl-(2-methoxyborylpropyl) boron or di-n-propyl-(2-methylmercaptopropyl)boron, which decompose to esters of di-n-propylboric or di-n-propylthioboric acids and polymers (-CH2- CH2-CH2B-X)n.

B. M. Mikhailov; E. N. Safonova

1965-01-01

261

Facile determination of double bond position in unsaturated fatty acids and esters by low temperature plasma ionization mass spectrometry.  

PubMed

Unsaturated fatty acids and esters can be oxidized in situ during ionization using a low temperature plasma (LTP) probe. The discharge generates ozone from air that reacts with and cleaves olefins. The molecular ions of the resulting acid/ester oxidation products are present in the full scan mass spectra and are confirmed by exact mass measurements. The fragmentation information can be used to assign double bond positions. We have successfully applied this strategy to a range of mono-/polyunsaturated fatty acids and fatty acid methyl/ethyl esters to assign their double bond locations. The procedure allows rapid and direct identification of double bond positions in situ at atmospheric pressure without sample preparation prior to mass spectrometric analysis. Microbial fatty acid ethyl ester (FAEE) mixtures from complex bacterial samples were directly analyzed by this method. Structural confirmation of their diagnostic ions by using exact mass measurements and tandem mass spectrometry confirms double bond positions in unsaturated bacterial FAEEs. PMID:21539336

Zhang, J Isabella; Tao, W Andy; Cooks, R Graham

2011-06-15

262

Occurrence of fatty acid short-chain-alkyl esters in fruits of Celastraceae plants.  

PubMed

Small amounts of a mixture of fatty acid short-chain-alkyl esters (FASCAEs) were obtained from the fruits of twelve plant species of Celastraceae family, and in five of them the FASCAEs were present not only in the arils but also in the seeds. These mixtures contained 32 individual FASCAE species, which formed four separate fractions, viz. FA methyl, ethyl, isopropyl, and butyl esters (FAMEs, FAEEs, FAIPEs, and FABEs, resp.). The FASCAE acyl components included the residues of 16 individual C??-C?? saturated, mono-, di-, and trienoic FAs. Linoleic, oleic, and palmitic acids, and, in some cases, also ?-linolenic acid predominated in FAMEs and FAEEs, while myristic acid was predominant in FAIPEs. It can be suggested that, in the fruit arils of some plant species, FAMEs and FAEEs were formed at the expense of a same FA pool characteristic of a given species and were strongly different from FAIPEs and FABEs esters regarding the mechanism of their biosynthesis. However, as a whole, the qualitative and quantitative composition of various FASCAE fractions, as well as their FA composition, varied considerably depending on various factors. Therefore, separate FASCAE fractions seem to be synthesized from different FA pools other than those used for triacylglycerol formation. PMID:23776017

Sidorov, Roman A; Zhukov, Anatoly V; Pchelkin, Vasily P; Vereshchagin, Andrei G; Tsydendambaev, Vladimir D

2013-06-01

263

Fumaric Acid and its Esters: An Emerging Treatment for Multiple Sclerosis  

PubMed Central

Fumaric acid is an intermediate product of the citric acid cycle that is a source of intracellular energy in the form of adenosine triphosphate (ATP). It is generated by oxidation of adenylsuccinate by the enzyme succinate dehydrogenase and is then converted to maleate by the enzyme fumarase. At present, fumaric acid esters (FAE) are licensed for the treatment of psoriasis. Several lines of evidence have demonstrated immunomodulatory effects for FAE. Clinical studies in psoriasis showed a reduction of peripheral CD4+- and CD8+-T-lymphocytes due to the ability of FAE to induce apoptosis. In vitro studies with the ester dimethyl fumarate (DMF) described an inhibitory effect on nuclear factor kappa B (NF-?B)-dependent transcription of tumor necrosis factor-alpha (TNF-?) induced genes in human endothelial cells. Animal studies using a model of central nervous system demyelination, MOG-induced experimental autoimmune encephalomyelitis (EAE), revealed a reduction of microglia and macrophages in inflamed lesions. A phase II clinical study in relapsing-remitting multiple sclerosis (RRMS) patients with a modified fumaric acid ester, BG-12, showed as "proof of principle" a significant reduction in the number of gadolinium enhancing lesions after 24 weeks of treatment as compared to placebo. Further phase III studies have now started to explore the long-term efficacy of FAE.

Moharregh-Khiabani, D; Linker, R.A; Gold, R; Stangel, M

2009-01-01

264

Esterification and transesterification of 9(10)-carboxystearic acid and its methyl esters. Kinetic studies  

Microsoft Academic Search

9(10)-Carboxystearic acid and its mono- and dimethyl esters were esterified and transesterified with 1-butanol, 2-methoxyethanol,\\u000a 2-chloroethanol, 2,2-dimethylpentanol, 2-ethylhexanol and 1-octanol. Rate studies for the sulfuric acid-catalyzed esterification\\u000a of 9(10)-carboxystearic acid to alkyl 9(10)-carboxystearate and alkyl 9(10)-carboalkoxystearate indicate than on an average\\u000a the terminal carboxyl is approximately 2627 times more reactive than the branched carboxyl group. Esterification is highly\\u000a dependent on

E. J. Dufek; R. O. Butterfield; E. N. Frankel

1972-01-01

265

Esters of Indole-3-Acetic Acid from Avena Seeds 1  

PubMed Central

The present studies showed that about 80% of the indole-3-acetic acid extractable from Avena kernels by aqueous acetone was esterified to polymers precipitable by ammonium sulfate and ethanol or acetone. The polymers were positively charged, being adsorbed to cation exchange columns at a pH of 3, or below, and eluted at a pH greater than 4. The polymers were heterogeneous with respect to size, about 5,000 to 20,000 daltons, and charge, exhibiting apparent pKa values of 4.2 and 4.7. The polymer fractions contained esterified IAA, anthrone-reactive material that liberated glucose upon acid hydrolysis, phenolic compounds, and peptidic material with a high proportion of hydrophobic amino acids. Since the esterified IAA was unstable, establishing polymer purity was not possible, and the designation IAA-glucoprotein fraction was adopted. Dehusked Avena kernels contained 8 mg/kg total IAA of which 5.5% was free and 94.5% esterified. IAA bound through a peptidic linkage was present, but in only trace amounts.

Percival, Frank W.; Bandurski, Robert S.

1976-01-01

266

Fatty Acid Ethyl and Methyl Ester Synthases, and Fatty Acid Anilide Synthase in HepG2 and AR42J Cells: Interrelationships and Inhibition by Tri o-tolyl Phosphate  

Microsoft Academic Search

Synthesis of fatty acid ethyl esters (FAEEs), fatty acid methyl esters (FAMEs), and fatty acid anilides (FAAs) in humans and\\/or experimental animals and in vitro have been reported by us and other investigators. In previous studies, we have demonstrated that fatty acid ethyl ester synthase (FAEES), purified from rat liver microsomes, is structurally and functionally identical to the rat liver

Bhupendra S. Kaphalia; Steven M. Green; G. A. S. Ansari

1999-01-01

267

Preparation of polyimides from mixtures of monomeric diamines and esters of polycarboxylic acids  

NASA Technical Reports Server (NTRS)

Polyimides having high thermal and oxidative stability are prepared by the reaction of a mixture of monomers comprising (1) a dialkyl or tetraalkyl ester of an aromatic tetracarboxylic acid; (2) an aromatic diamine; and (3) a monoalkyl or dialkyl ester of a dicarboxylic acid where in the ratio of a:b:c is n:(n+1):2, wherein n has a value from 1 to 20. The mixture of monomers is prepared in a 30 to 70 percent by weight solution of an organic solvent, a substrate impregnated with the solution and heated at 50 to 205 C to remove said solvent and form a low molecular weight prepolymer, and thereafter heated at 275 to 350 C to cure to a high molecular weight polyimide.

Serafini, T. T.; Delvigs, P.; Lightsey, G. R. (inventors)

1973-01-01

268

Development of efficient Lewis acid catalysts for intramolecular cycloaddition reactions of ester-tethered substrates.  

PubMed

We have developed novel bidentate Lewis acids that efficiently promote the intramolecular cycloaddition reactions of ester-tethered substrates. Bis-aluminated triflic amide derivatives [TfN(AlR(1)R(2))2], which are generated by simply mixing triflic amide and 2 equiv of methyl aluminum or aluminum hydride, catalyzed intramolecular Diels-Alder (DA) reactions of ester-tethered 1,7,9-trienes and intermolecular DA reactions of alpha,beta-unsaturated lactones. We also found that bimetallic Lewis acid derived from 1,1'-biphenyl-2,2'-di(triflyl)amide and dimethylaluminum chloride promoted the intramolecular [3 + 2] cycloaddition reaction of acrylate derivatives having an allylsilane part. PMID:17549689

Taguchi, Takeo; Saito, Akio; Yanai, Hikaru

2007-01-01

269

Precombustion of fatty acids and esters of biodiesel. A possible explanation for differing cetane numbers  

Microsoft Academic Search

Fatty acids of C18 chainlength as well as their methyl, ethyl, n-propyl, and n-butyl esters were injected into a constant-volume combustion apparatus suitable for collecting material from the fuel spray\\u000a prior to the onset of ignition. The collected material from this precombustion phase of the injection event was analyzed by\\u000a gas chromatography-mass spectrometry. Compounds identified as forming during the precombustion

Gerhard Knothe; Marvin O. Bagby; Thomas W. Ryan

1998-01-01

270

Oxidative stability and storage behavior of fatty acid methyl esters derived from used palm oil  

Microsoft Academic Search

Fatty acid alkyl esters, especially FAME, are the most commonly used liquid biofuel. Because biofuels are expected to be important\\u000a alternative renewable energy sources in the near future, more studies on their stability against oxidation need to be addressed.\\u000a Biofuel derived from vegetable oils is well researched, currently with more attention focused on the reuse of waste oil sources\\u000a than

Soh-Kheang Loh; Soo-Mooi Chew; Yuen-May Choo

2006-01-01

271

Antiproliferation and radiosensitization of caffeic acid phenethyl ester on human medulloblastoma cells  

Microsoft Academic Search

Purpose: To investigate antiproliferative and radiosensitizing effects of caffeic acid phenethyl ester (CAPE) on medulloblastoma\\u000a (MB) Daoy cells. Methods and materials: Daoy cells were treated with CAPE in different concentrations and assessed for cell viability, apoptosis, cell cycles, cyclin\\u000a B1 expressions, radiosensitization and chemosensitization. Human astroglia SVGp12 cells were treated with CAPE to present\\u000a the possible protection or complication effects

Yi-Hsien Lin; Jen-Hwey Chiu; Wen-Ser Tseng; Tai-Tong Wong; Shih-Hwa Chiou; Sang-Hue Yen

2006-01-01

272

Solutol HS 15, Nontoxic Polyoxyethylene Esters of 12-Hydroxystearic Acid, Reverses Multidrug Resistance1  

Microsoft Academic Search

A recently developed non-ionic surfactant called Solutol IIS 15 (poly- oxyethylene esters of 12-hydroxystearic acid), with low toxicity in vivo, was shown to reverse completely the multidrug resistance of KB 8-5 and KB 8-5-11 human epidermoid carcinoma cells in vitro but did not potentiate drug toxicity in drug-sensitive KB3-1 cells. At a concentration of 10% of its own ICso (mean

John S. Coon; Warren Knudson; Kathleen Clodfelter; Bing Lu; Ronald S. Weinstein

273

Effect of methyl ester of aristolic acid from Aristolochia indica Linn. on fertility of female mice.  

PubMed

Methyl ester of aristolic acid, a pure compound isolated from the roots of Aristolochia indica (Linn.), was found to exert 100% abortifacient activity at a single oral dose of 60 mg/kg b. wt when administered on 6th or 7th day of pregnancy; 20 and 25% abortifacient effect were observed at the same dose on day 10 and 12, respectively. PMID:720520

Pakrashi, A; Shaha, C

1978-09-15

274

Fatty acid esters of 3-chloropropane-1,2-diol in edible oils  

Microsoft Academic Search

A series of 25 virgin and refined edible oils, obtained from retailers, was analyzed for levels of free 3-chloropropane-1,2-diol (3-MCPD) and 3-MCPD released from esters with higher fatty acids (bound 3-MCPD). Oils containing free 3-MCPD ranging from <3?g?kg (LOD) to 24?g?kg. Surprisingly, bound 3-MCPD levels were much higher and varied between <100 (LOD) and 2462?g?kg. On average, virgin oils had

Z. Zelinkov; B. Svejkovsk; J. Velek; M. Doleal

2006-01-01

275

Low chain esters of stearic acid as phase change materials for thermal energy storage in buildings  

Microsoft Academic Search

Esterification of different commercial mixtures of stearic and palmitic acid with methyl, butyl and propyl alcohols was undertaken at the laboratory scale and the thermal properties of the esters were determined by Differential Scanning Calorimetry (DSC).Twelve products were obtained with melting points in the interval of 1734C and freezing points in the range of 2032C. About half of them are

D. Feldman; D. Banu; D. Hawes

1995-01-01

276

Effects of phthalic acid esters (PAEs) on the neonate and aspects of teratogenic actions.  

PubMed Central

A review of the literature reveals that several different phthalic acid esters (PAEs) are capable of causing testicular damage. Phthalate-induced zinc deficiency is consistent with germinal epithelial damage. Among experimental animals, mice perhaps show the greatest sensitivity to phthalate-induced terata, but high doses/exposure are required. Little toxicologic information is available with regard to phthalate-induced effects upon the neonate.

Thomas, J A; Wienckowski, D B; Gillies, B A; Thomas, M J; Youkilis, E J

1986-01-01

277

Iontophoretic delivery of 5-aminolevulinic acid and its methyl ester using a carbopol gel as vehicle  

Microsoft Academic Search

The aim of this study was to evaluate a Carbopol gel as a vehicle for iontophoretic delivery of 5-aminolevulinic acid (ALA) and its methyl ester (m-ALA). The formulation was characterized rheologically and the passive diffusion of ALA and m-ALA in the gels was measured. Addition of ALA and m-ALA did not change the rheological behavior of the gel and the

Nadia Merclin; Tobias Bramer; Katarina Edsman

2004-01-01

278

Study of the Pharmacokinetic Interaction Between Simvastatin and Prescription Omega3Acid Ethyl Esters  

Microsoft Academic Search

The coadministration of prescription omega-3-acid ethyl esters (P-OM3) with a statin may present a treatment option for patients with mixed hyperlipidemia. This open-label, randomized, 2-way crossover, drug-drug interaction study evaluated the impact of P-OM3 capsules on plasma simvastatin pharmacokinetics in 24 healthy volunteers. Under fasted conditions, 80 mg simvastatin was administered with or without 4 g P-OM3 for two 14-day

J. M. McKenney; D. Swearingen; M. Di Spirito; R. Doyle; C. Pantaleon; D. Kling; R. A. Shalwitz

2006-01-01

279

Quinic acid esters from Pluchea indica with collagenase, MMP-2 and MMP-9 inhibitory activities.  

PubMed

Investigation of collagenase inhibitory natural components afforded two quinic acid esters (1 and 2) and quercetin (3) from the leaves of Pluchea indica (Compositae). Of these, compounds 1 and 2 exhibited collagenase inhibitory activity (IC(50)) at a concentration of less than 10 microm, and 1 showed matrix metalloproteinase (MMP)-2 and -9 inhibitory activity (IC(50)) at 2.5 and 6.4 microm, respectively. PMID:17726735

Ohtsuki, Takashi; Yokosawa, Emiko; Koyano, Takashi; Preeprame, Srisomporn; Kowithayakorn, Thaworn; Sakai, Shinobu; Toida, Toshihiko; Ishibashi, Masami

2008-02-01

280

Misidentification of soil bacteria by fatty acid methyl ester (FAME) and BIOLOG analyses  

Microsoft Academic Search

Fatty acid methyl ester (FAME) analysis is commonly used by soil scientists as a sole method for identifying soil bacteria.\\u000a We observed discrepancies with this method for identifying certain species of bacteria. Therefore, we used carbon substrate\\u000a oxidation patterns (BIOLOG) and some simple physical and chemical tests to determine the extent of these discrepancies. Identification\\u000a with FAME profiles gave false

N. Oka; P. G. Hartel; O. Finlay-Moore; J. Gagliardi; D. A. Zuberer; J. J. Fuhrmann; J. S. Angle; H. D. Skipper

2000-01-01

281

Antioxidant and antimelanogenic properties of rosmarinic acid methyl ester from Origanum vulgare  

Microsoft Academic Search

Rosmarinic acid methyl ester (Ov-8) was isolated form Origanum vulgare. The antioxidant activities of Ov-8 were evaluated by measuring radical-scavenging activities, reducing power, and inhibition of lipid peroxidation, using liposomes and mice tissue. The percentage inhibition, by Ov-8, of the activities of reactive oxygen species (ROSs) in H2O2-treated BNLCL2 cells was about 116.082.3% of that in H2O2-treated cells. The ability

Hsiou-Yu Ding; Tzung-Han Chou; Chia-Hua Liang

2010-01-01

282

Modeling the hydrolysis of perfluorinated compounds containing carboxylic and phosphoric acid ester functions and sulfonamide groups  

Microsoft Academic Search

Temperature-dependent rate constants were estimated for the acid- and base-catalyzed and neutral hydrolysis reactions of perfluorinated telomer acrylates (FTAcrs) and phosphate esters (FTPEs), and the SN1 and SN2 hydrolysis reactions of fluorotelomer iodides (FTIs). Under some environmental conditions, hydrolysis of monomeric FTAcrs could be rapid (half-lives of several years in marine systems and as low as several days in some

Sierra Rayne; Kaya Forest

2010-01-01

283

The distribution of ester-linked ferulic acid in the cell walls of angiosperms  

Microsoft Academic Search

Ester-linked ferulic acid occurs in the cell walls of two major groups of angiosperms, the commelinid monocotyledons and the\\u000a core Caryophyllales, at concentrations >3.5mgg?1 cell walls, and has been detected in primary cell walls by its autofluorescence using ultraviolet fluorescence microscopy.\\u000a Both of these groups are resolved as monophyletic clades in phylogenetic trees constructed using gene sequences. In the primary

Philip J. Harris; Jason A. K. Trethewey

2010-01-01

284

Caffeic acid phenethyl ester inhibits nitric oxide synthase gene expression and enzyme activity  

Microsoft Academic Search

Since nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been known to be involved in inflammatory and autoimmune-mediated tissue destruction, modulation of NO synthesis or action represents a new approach to the treatment of inflammatory and autoimmune diseases. Caffeic acid phenethyl ester (CAPE), an active component of honeybee propolis, has been identified to show anti-inflammatory, anti-viral and

Yun Seon Song; Eun-Hee Park; Gang Min Hur; Young Sue Ryu; Yong Sup Lee; Jae Yeol Lee; Yong Man Kim; Changbae Jin

2002-01-01

285

Lysosomal acid lipase deficiency: wolman disease and cholesteryl ester storage disease.  

PubMed

(Full text is available at http://www.manu.edu.mk/prilozi). Cholesteryl ester storage disease (CESD, OMIM #278000) and Wolman disease (OMIM #278000) are autosomal recessive lysosomal storage disorders caused by a deficient activity of lysosomal acid lipase (cholesteryl ester hydrolase, LAL). Human lysosomal acid lipase is essential for the metabolism of cholesteryl esters and triglycerides. In Wolman disease, LAL activity is usually absent, whereas CESD usually presents some residual LAL activity. In infants, poor weight gain, massive hepatosplenomegaly, calcified adrenal glands (present about 2/3 of the time), vomiting, diarrhea and failure to thrive are indicative of Wolman disease. The clinical picture is more variable in CESD. Hepatomegaly and/or elevation of liver transaminases are almost always present. Hepatic steatosis often leads to fibrosis and cirrhosis. Other signs often include splenomegaly, high total cholesterol and LDL-cholesterol, elevated triglycerides, and low HDL-cholesterol. The diagnosis of LAL deficiency requires clinical experience and specialized laboratory tests. The diagnosis is based on finding deficient activity of acid lipase and/or molecular tests. Pilot screening projects using dried blood spot testing in 1) children with atypical fatty liver disease in the absence of overweight, 2) patients with dyslipidaemia and presence of hepatomegaly and/or elevated transaminases, 3) newborns/neonates with hepatomegaly and abdominal distension/failure to thrive/elevated transaminases are currently underway. Early diagnosis is particularly important for the enzyme replacement therapy. Human trials with recombinant LAL are currently ongoing, raising the prospect for specific correction of LAL deficiency in this progressive and often debilitating disorder. Key words: lysosomal acid lipase deficiency, Wolman disease, cholesteryl ester storage disorder. PMID:24798600

Tylki-Szyma?ska, A; Jurecka, A

2014-01-01

286

Esters of okadaic acid and dinophysistoxin-2 in Portuguese bivalves related to human poisonings  

Microsoft Academic Search

Liquid chromatography (HPLC) was used to search for esters of DSP toxins in Portuguese bivalves. Hexane-soluble derivatives of okadaic acid (OA) and dinophysistoxin-2 (DTX-2) were found. Presumably they are acyl derivatives, globally known as `dinophysistoxin-3' (DTX-3). In certain instances DTX-3 content surpassed 50% of the total amount of DSP toxins. A human diarrhetic poisoning (DSP) incident with Donax clams (Donax

Paulo Vale; Maria Antnia; M. Sampayo

1999-01-01

287

Electron paramagnetic resonance studies of gamma-irradiated DL-alanine ethyl ester hydrochloride, L-theanine and L-glutamic acid dimethyl ester hydrochloride.  

PubMed

The electron paramagnetic resonance (EPR) of gamma irradiated powders of DL-alanine ethyl ester hydrochloride, L-theanine and L-glutamic acid dimethyl ester hydrochloride were investigated at room temperature. The observed paramagnetic species were attributed to the CH3?HCOOC2H5, -CH2?HCOOH and -CH2?HCOOCH3 radicals, respectively. Hyperfine structure constants and g-values were determined for these three radicals. Some spectroscopic properties and suggestions concerning the possible structure of the radicals were also discussed. PMID:23680512

Ba?kan, M Halim; Ayd?n, Murat

2013-08-01

288

Electron paramagnetic resonance studies of gamma-irradiated DL-alanine ethyl ester hydrochloride, L-theanine and L-glutamic acid dimethyl ester hydrochloride  

NASA Astrophysics Data System (ADS)

The electron paramagnetic resonance (EPR) of gamma irradiated powders of DL-alanine ethyl ester hydrochloride, L-theanine and L-glutamic acid dimethyl ester hydrochloride were investigated at room temperature. The observed paramagnetic species were attributed to the CH3?HCOOC2H5, -CH2?HCOOH and -CH2?HCOOCH3 radicals, respectively. Hyperfine structure constants and g-values were determined for these three radicals. Some spectroscopic properties and suggestions concerning the possible structure of the radicals were also discussed.

Ba?kan, M. Halim; Ayd?n, Murat

2013-08-01

289

Intra- and intermolecular forces dependent main chain conformations of esters of ?,?-dehydroamino acids  

NASA Astrophysics Data System (ADS)

Esters of dehydroamino acids occur in nature. To investigate their conformational properties, the low-temperature structures of Ac-?Ala-OMe, Ac-?Val-OMe, Z-(Z)-?Abu-OMe, and Z-(Z)-?Abu-NHMe were studied by single-crystal X-ray diffraction. The ?Ala ester prefers the fully extended conformation C5. Both the ?Val and (Z)-?Abu esters assume the conformation ?, whereas the amide analogue of the latter prefers the conformation ?. For the conformations found, DFT calculations using B3LYP/6-311++G(d,p) with the SCRF-PCM and M062X/6-311++G(d,p) with the SCRF-SMD method were applied to mimicking chloroform and water environment. The tendency of the ?Val and (Z)-?Abu esters towards the conformation ?, and their amide analogues towards the conformation ?, with increase of the polarity of environment was found. The analysis of both intra- and intermolecular interactions including hydrogen bonds, carbonyl dipole attraction, and ?-electron conjugation, enabled to understand and elucidate the conformational preferences of studied compounds. The studies show how the molecular structure, and in consequence, the conformation adopted by molecules is influenced by the different intra- and intermolecular forces.

Siod?ak, Dawid; Bujak, Maciej; Sta?, Monika

2013-09-01

290

GC-based analysis of plant stanyl fatty acid esters in enriched foods.  

PubMed

Approaches for the capillary gas chromatographic (GC) based analysis of intact plant stanyl esters in enriched foods were developed. Reference compounds were synthesized by enzyme-catalyzed transesterifications. Their identities were confirmed by means of mass spectrometry. Using a medium polar trifluoropropylmethyl polysiloxane stationary phase, long-chain plant stanyl esters could be separated according to their stanol moieties and their fatty acid chains. Thermal degradation during GC analysis was compensated by determining response factors; calibrations were performed for ten individual plant stanyl esters. For the analysis of low-fat products (skimmed milk drinking yogurts), the GC separation was combined with a "fast extraction" under acidic conditions. For fat-based foods (margarines), online coupled LC-GC offered an elegant and efficient way to avoid time-consuming sample preparation steps. The robust and rapid methods allow conclusions on both, the stanol profiles and the fatty acid moieties, and thus provide a basis for the authentication of this type of functional food ingredients. PMID:21486072

Barnsteiner, Andreas; Lubinus, Tim; di Gianvito, Angelica; Schmid, Wolfgang; Engel, Karl-Heinz

2011-05-25

291

Amino Acid esters substituted phosphorylated emtricitabine and Didanosine derivatives as antiviral and anticancer agents.  

PubMed

Owing to the promising antiviral activity of amino acid ester-substituted phosphorylated nucleosides in the present study, a series of phosphorylated derivatives of emtricitabine and didanosine substituted with bioactive amino acid esters at P-atom were synthesized. Initially, molecular docking studies were screened to predict their molecular interactions with hemagglutinin-neuraminidase protein of Newcastle disease virus and E2 protein of human papillomavirus. The title compounds were screened for their antiviral ability against Newcastle disease virus (NDV) by their in ovo study in embryonated chicken eggs. Compounds 5g and 9c exposed well mode of interactions with HN protein and also exhibited potential growth of NDV inhibition. The remaining compounds exhibited better growth of NDV inhibition than their parent molecules, i.e., emtricitabine (FTC) and didanosine (ddI). In addition, the in vitro anticancer activity of all the title compounds were screenedagainst HeLa cell lines at 10 and 100?g/mL concentrations. The compounds 5g and 9c showed an effective anticancer activity than that of the remaining title compounds with IC50 values of 40 and 60?g/mL, respectively. The present in silico and in ovo antiviral and in vitro anticancer results of the title compounds are suggesting that the amino acid ester-substituted phosphorylated FTC and ddI derivatives, especially 5g and 9c, can be used as NDV inhibitors and anticancer agents for the control and management of viral diseases with cancerous condition. PMID:24789416

Sekhar, Kuruva Chandra; Janardhan, Avilala; Kumar, Yellapu Nanda; Narasimha, Golla; Raju, Chamarthi Naga; Ghosh, S K

2014-07-01

292

Energetics of the lighter chalcogen analogues of carboxylic acid esters.  

PubMed

In the current paper we present the results of our quantum chemical (G2, G2(MP2), and G3) study of the structure and energetics of carboxylic acids and their chalcogen analogues. In the particular, calculations and accompanying natural bond orbital (NBO) and atoms in molecules (AIM) analyses were performed on all species with the generic formula RC(?X)YR' (X, Y = O, S, Se and R = R' = CH(3)). Energies, enthalpies, and free energies of formation, resonance energies, interchalcogen methyl transfer energies and their energies of activation, and heavy atom bond lengths and angles are all discussed. A comparison of the calculated results with the sparse experimentally available data shows good agreement. Trends are also presented. PMID:21028778

Deakyne, Carol A; Ludden, Alicia K; Roux, Maria Victoria; Notario, Rafael; Demchenko, Alexei V; Chickos, James S; Liebman, Joel F

2010-12-16

293

Caffeic acid phenethyl ester prevents apoptotic cell death in the developing rat brain after pentylenetetrazole-induced status epilepticus.  

PubMed

Population-based studies suggest that seizure incidence is highest during the first year of life, and early-life seizures frequently result in the development of epilepsy and behavioral alterations later in life. The early-life insults like status epilepticus often lead to epileptogenesis, a process in which initial brain injury triggers cascades of molecular, cellular, and network changes and eventually spontaneous seizures. Caffeic acid phenethyl ester is an active component of propolis obtained from honeybees and has neuroprotective properties. The aim of this study was to investigate whether caffeic acid phenethyl ester exerts neuroprotective effects on the developing rat brain after status epilepticus. Twenty-one dams reared Wistar male rats, and 21-day-old rats were divided into three groups: control group, pentylenetetrazole-induced status epilepticus group, and caffeic acid phenethyl ester-treated group. Status epilepticus was induced on the first day of experiment. Caffeic acid phenethyl ester injections (30 mg/kg intraperitoneally) started 40 min after the tonic phase of status epilepticus was reached, and the injections of caffeic acid phenethyl ester were repeated over 5 days. Rats were sacrificed, and brain tissues were collected on the 5th day of experiment after the last injection of caffeic acid phenethyl ester. Apoptotic cell death was evaluated. Histopathological examination showed that caffeic acid phenethyl ester significantly preserved the number of neurons in the CA1, CA3, and dentate gyrus regions of the hippocampus and the prefrontal cortex. It also diminished apoptosis in the hippocampus and the prefrontal cortex. In conclusion, this experimental study suggests that caffeic acid phenethyl ester administration may be neuroprotective in status epilepticus in the developing rat brain. PMID:24012504

Yi?, Ulu; Topu, Yasemin; zbal, Seda; Tu?yan, Kaz?m; Bayram, Erhan; Karakaya, Pakize; Yilmaz, Osman; Kurul, Semra H?z

2013-11-01

294

Thermolysis of the esters of substituted 3,7-triazabicydo[3.3.0]oct-3-ene-4-carboxylic acids  

Microsoft Academic Search

Heating to 190200C of the esters of substituted 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acids afforded esters of\\u000a 3-azabicyclo[3.1.0]hexane-6-carboxylic acids as a mixture of exo and endo isomers. The reaction carried out in chlorobenzene\\u000a at 130C in the presence of copper stearate yielded only exo isomers.

S. A. Molchanov; A. V. Stepakov; R. R. Kostikov

2000-01-01

295

Syntheses of Benzo[b]furan-6-carbonitrile and 6-Cyanobenzo[b]furan-2-boronic Acid Pinacol Ester  

PubMed Central

6-Cyanobenzo[b]furan-2-boronic acid pinacol ester (10) is a potentially useful 2-point scaffold for the construction of specific compounds or compound libraries with benzofuran cores. Using a per-iodination/de-iodination strategy coupled with a Sonogashira alkynylation and Cu-catalyzed heteroannulation, we have developed a procedure that allows the preparation of benzo[b]furan-6-carbonitrile (9) and 6-cyanobenzo[b]furan-2-boronic acid pinacol ester (10) in gram quantities.

Williams, John D.; Ding, Xiaoyuan; Nguyen, Son; Vines, Kimberly K.; Peet, Norton P.

2013-01-01

296

ETHANOL-INDUCED CYTOTOXICITY IN RAT PANCREATIC ACINAR AR42J CELLS: ROLE OF FATTY ACID ETHYL ESTERS  

Microsoft Academic Search

Aims: To understand the mechanism(s) of alcoholic pancreatitis and role of fatty acid ethyl esters (FAEEs, non- oxidative metabolites of ethanol) in ethanol-induced pancreatic injury. Methods: A time- and concentration-dependent synthesis of FAEEs and the cytotoxicity of ethanol and its predominant fatty acid esters were studied in rat pancreatic tumour (AR42J) cells in cultures. Role of FAEEs in ethanol-induced cytotoxicity

HAI WU; KAMLESH K. BHOPALE; G. A. S. ANSARI; BHUPENDRA S. KAPHALIA

297

The isolation of omega-3 polyunsaturated fatty acids and methyl esters of fish oils by silver resin chromatography  

Microsoft Academic Search

Multigram quantities of the highly unsaturated ?3 component from samples of fish oil fatty acids and esters were isolated\\u000a by silver resin chromatography. An XN1010 resin column saturated with silver ions was utilized. Polyunsaturated fatty acid\\u000a (PUFA) esters from fish oil concentrate (FOC) were fractionated based on the number of double bonds by using solvent programming\\u000a (acetonitrile in methanol). Larger

R. O. Adlof; E. A. Emken

1985-01-01

298

A mutant leucine aminopeptidase from Streptomyces cinnamoneus with enhanced L-aspartyl L-amino acid methyl ester synthetic activity.  

PubMed

L-aspartyl L-amino acid methyl ester was synthesized using a mutant of a thermostable leucine aminopeptidase from Streptomyces cinnamoneus, D198 K SSAP, obtained in previously. A peptide of high-intensity sweetener, L-aspartyl-L-phenylalanine methyl ester, was selected as a model for demonstrating the synthesis of L-aspartyl L-amino acid methyl ester. The hydrolytic activities of D198 K SSAP toward L-aspartyl-L-phenylalanine and its methyl ester were, respectively, 74-fold and fourfold higher than those of wild type. Similarly, the initial rate of the enzyme for L-aspartyl-L-phenylalanine methyl ester synthesis was over fivefold higher than that of wild-type SSAP in 90% methanol (v/v) in a one-pot reaction. Furthermore, other L-aspartyl L-amino acid methyl esters were synthesized efficiently using D198 K SSAP. Results show that the substitution of Asp198 of SSAP with Lys is effective for synthesizing L-aspartyl L-amino acid methyl ester. PMID:22354473

Arima, Jiro; Kono, Mirai; Kita, Manami; Mori, Nobuhiro

2012-06-01

299

Synergistic cosolubilization of omega-3 fatty acid esters and CoQ10 in dilutable microemulsions.  

PubMed

Water-dilutable microemulsions were prepared and loaded with two types of omega-3 fatty acid esters (omega-3 ethyl esters, OEE; and omega-3 triacylglycerides, OTG), each separately and together with ubiquinone (CoQ(10)). The microemulsions showed high and synergistic loading capabilities. The linear fatty acid ester (OEE) solubilization capacity was greater than that of the bulky and robust OTG. The location of the guest molecules within the microemulsions at any dilution point were determined by electrical conductivity, viscosity, DSC, SAXS, cryo-TEM, SD-NMR, and DLS. We found that OEE molecules pack well within the surfactant tails to form reverse micelles that gradually, upon water dilution, invert into bicontinuous phase and finally into O/W droplets. The CoQ(10) increases the stabilization and solubilization of the omega-3 fatty acid esters because it functions as a kosmotropic agent in the micellar system. The hydrophobic and bulky OTG molecule strongly interferes with the tail packing and spaces them significantly - mainly in the low and medium range water dilutions. When added to the micellar system, CoQ(10) forms some reverse hexagonal mesophases. The inversion into direct micelles is more difficult in comparison to the OEE system and requires additional water dilution. The OTG with or without CoQ(10) destabilizes the structures and decreases the solubilization capacity since it acts as a chaotropic agent to the micellar system and as a kosmotropic agent to hexagonal packing. These results explain the differences in the behavior of these molecules with vehicles that solubilize them in aqueous phases. Temperature disorders the bicontinuous structures and reduces the supersaturation of the system containing OEE with CoQ(10); as a result CoQ(10) crystallization is retarded. PMID:21723268

Deutch-Kolevzon, Rivka; Aserin, Abraham; Garti, Nissim

2011-10-01

300

Developing intestine is injured during absorption of oleic acid but not its ethyl ester.  

PubMed Central

Although lipids are essential nutrients in the mammalian diet, we have shown that fatty acids are injurious to epithelial cells of developing piglet intestine during luminal perfusion. Furthermore, the intestine of young animals sustains greater injury than that of older piglets. In an effort to understand the mechanism for this developmental injury, we investigated whether changes in the chemical configuration of oleic acid would alter this damage. Mucosal permeability, as quantitated by the plasma-to-lumen clearance of 51chromium EDTA, was evaluated during luminal perfusion with oleic acid as compared with its ethyl (ethyl oleate) and glyceryl (glycerol-1-mono-oleate) esters, solubilized with taurocholic acid, in jejunum of 1-d-, 3-d-, 2-wk-, and 1-mo-old piglets. 51Chromium EDTA clearance increased significantly during oleic acid and glycerol-1-mono-oleate perfusion, but did not increase during perfusion with ethyl oleate or saline. This result was not secondary to failure of absorption of ethyl oleate, as [14C]oleic acid and ethyl [1-14C]oleate were absorbed to a similar extent. Furthermore, developing intestine was able to remove the ethyl group and then re-esterify the fatty acid to form triacyglycerol. These studies indicate that oleic acid-induced mucosal injury can be abolished when the carboxylic group of the fatty acid is esterified with an ethyl, but not a glycerol, group. Since the ethyl ester is also absorbed and metabolized similarly to the free fatty acid, this may provide a means of supplying long-chain fatty acids to developing intestine without causing mucosal damage. Images

Velasquez, O R; Place, A R; Tso, P; Crissinger, K D

1994-01-01

301

An attenuated total reflectance IR study of silicic acid adsorbed onto a ferric oxyhydroxide surface  

NASA Astrophysics Data System (ADS)

Silicic acid (H 4SiO 4) can have significant effects on the properties of iron oxide surfaces in both natural and engineered aquatic systems. Understanding the reactions of H 4SiO 4 on these surfaces is therefore necessary to describe the aquatic chemistry of iron oxides and the elements that associate with them. This investigation uses attenuated total reflectance infrared spectroscopy (ATR-IR) to study silicic acid in aqueous solution and the products formed when silicic acid adsorbs onto the surface of a ferrihydrite film in 0.01 M NaCl at pH 4. A spectrum of 1.66 mM H 4SiO 4 at pH 4 (0.01 M NaCl) has an asymmetric Si-O stretch at 939 cm -1 and a weak Si-O-H deformation at 1090 cm -1. ATR-IR spectra were measured over time (for up to 7 days) for a ferrihydrite film (?1 mg) approaching equilibrium with H 4SiO 4 at concentrations between 0.044 and 0.91 mM. Adsorbed H 4SiO 4 had a broad spectral feature between 750 and 1200 cm -1 but the shape of the spectra changed as the amount of H 4SiO 4 adsorbed on the ferrihydrite increased. When the solid phase Si/Fe mole ratio was less than ?0.01 the ATR-IR spectra had a maximum intensity at 943 cm -1 and the spectral shape suggests that a monomeric silicate species was formed via a bidentate linkage. As the solid phase Si/Fe mole ratio increased to higher values a discrete oligomeric silicate species was formed which had maximum intensity in the ATR-IR spectra at 1001 cm -1. The spectrum of this species suggests that it is larger than a dimer and it was tentatively identified as a cyclic tetramer. A small amount of a polymeric silica phase with a broad spectral feature centered at ?1110 cm -1 was also observed at high surface coverage. The surface composition was estimated from the relative contribution of each species to the area of the ATR-IR spectra using multivariate curve resolution with alternating least squares. For a ferrihydrite film approaching equilibrium with 0.044, 0.14, 0.40 and 0.91 mM H 4SiO 4 the area of the spectra accounted for by monomeric species were 92%, 49%, 23% and 6%, respectively. The remainder was oligomer apart from a small amount (<5%) of polymerized silica at the two higher H 4SiO 4 concentrations. The solid phase Si/Fe mole ratios for these samples were 0.020, 0.037, 0.071 and 0.138, respectively.

Swedlund, Peter J.; Miskelly, Gordon M.; McQuillan, A. James

2009-07-01

302

The surface chemistry of simple and complex silicate minerals in acid solutions  

SciTech Connect

Proton-promoted dissolution of aluminosilicate minerals (e.g. plagioclase feldspar) in aqueous solutions is a complex process which occurs by hydrogen infiltration into the structure and leaching of M[sup 1+]-M[sup 3+] elements, followed by repolymerization of the residual silica-rich surface to yield an amorphous, leached-layer. The authors have extended this research to simple orthosilicate and pyroxene minerals in order to relate their dissolution rates in acid solutions to the rates of solvent exchange between aquated divalent ions and solvent water. Experimental rate measurements scale with water exchange rates suggesting that silicate dissolution is controlled by the character of short-range metal-oxygen bonds. One estimate of these bond energies is provided by lattice energy calculations for ionic crystals. Preliminary evaluation of these binding energies for olivine structure minerals suggests that dissolution rates roughly correlate with the coulombic energy contribution of the total lattice energy. Examination of acid-reacted, orthosilicate powders and single crystals by electron and ion beam techniques suggests the presence of an amorphous leach layer about 10--20 nm thick for phenacite (Be[sub 2]SiO[sub 4]; olivine structure), with deep (> 200 nm) leaching of Be[sup 2+] from the crystal interior. This was not observed for olivine crystals (FO[sub 92]). A Si-rich, leach layer was observed for acid-reacted wollastonite. These results imply that isolated or chain-linked SiO[sub 4] tetrahedra in olivine or pyroxene structures can repolymerize if dissolution is slow enough, and that leach layers might be commonly found on weathered silicate minerals.

Westrich, H.R.; Cygan, R.T.; Arnold, G.W. (Sandia National Lab., Albuquerque, NM (United States)); Casey, W.H. (Univ. of California, Davis, CA (United States). Dept. of Land, Air, and Water Resources)

1992-01-01

303

Synthesis, primary photophysical and antibacterial properties of naphthyl ester cinoxacin and nalidixic acid derivatives.  

PubMed

We have synthesized two naphthyl ester quinolone derivates and determined their ability to generate reactive oxygen species (ROS) such as (1)O(2), ()OH, H(2)O(2) upon photolysis with UV-A light. The ability of cinoxacin (1) and nalidixic acid (2), and their naphthyl ester derivatives (3 and 4) to generate a dose-dependent amount of singlet oxygen and ROS (()(-)O(2), ()OH) in cell-free systems was detected by histidine assay and by luminol-enhanced chemiluminescence (LCL), respectively. Their electronic absorption and emission spectra were quantified and their photostability was determined. Their tendency to generate peroxidic derivative species showed the following order: 3>4; in contrast, their ability to generate singlet oxygen was 4>3 and these were better sensitizers than their parent quinolones 1 and 2. The antibacterial activity in darkness and under irradiation of compounds 3 and 4 was tested on Escherichia coli and compared with that of their parent compounds. An enhanced antibacterial activity by irradiation of the naphthyl esters of cinoxacin and nalidixic acid on E. coli was observed. PMID:18562206

Vargas, Franklin; Zoltan, Tamara; Rivas, Carlos; Ramirez, Alvaro; Cordero, Tulynan; Daz, Yrene; Izzo, Carla; Crdenas, Ylec M; Lpez, Vernica; Gmez, Lubimar; Ortega, Jessenia; Fuentes, Alberto

2008-08-21

304

Inhibition of metallo-beta-lactamases by a series of mercaptoacetic acid thiol ester derivatives.  

PubMed Central

A series of mercaptoacetic acid thiol esters have been identified as metallo-beta-lactamase inhibitors. Electrospray mass spectrometry (ESMS) has shown that irreversible inhibition of the Bacillus cereus II metallo-beta-lactamase by SB214751, SB214752, and SB213079 was concomitant with a 90-Da increase in mass of the enzyme. Tryptic digestion of the B. cereus II inhibited with SB214751 illustrated that the peptide fragment, containing the only cysteine of the enzyme, had undergone a mass increment of 90 Da. It was further demonstrated that B. cereus II hydrolyzed this type of compound across the thiol ester bond to yield mercaptoacetic acid. Mercaptoacetic acid is the only molecular fragment common to SB214751, SB214752, and SB213079, and free mercaptoacetic acid does not bind covalently to B. cereus II. Therefore, it is concluded that these compounds inhibit B. cereus II by the mechanism-based delivery of mercaptoacetic acid, forming a disulfide linkage with the active sites cysteine (predicted mass shift = +90 Da) under the aerobic conditions of the assay. The different thiol esters examined had a broad range of potencies against the metallo-beta-lactamases tested. For example SB214751, SB214752, and SB213079 all had 50% inhibitory concentrations of < 10 and > 1,000 microM for the Stenotrophomonas maltophilia L-1 and Bacteroides fragilis CfiA enzymes, respectively. SB216968 was particularly active against the Aeromonas hydrophila CphA metallo-beta-lactamase and was found to be an uncompetitive inhibitor of this enzyme (Ki = 3.9 microM), whereas it exhibited irreversible inhibition of the L-1 enzyme. These observations with this series of compounds have revealed subtle differences between the active sites of different metallo-beta-lactamases. Finally, a novel application for isothermal titration calorimetry for assessing the zinc chelating activity of candidate inhibitors is also presented.

Payne, D J; Bateson, J H; Gasson, B C; Proctor, D; Khushi, T; Farmer, T H; Tolson, D A; Bell, D; Skett, P W; Marshall, A C; Reid, R; Ghosez, L; Combret, Y; Marchand-Brynaert, J

1997-01-01

305

Specific Inhibition of the Polymorphonuclear Leukocyte Chemotactic Response to Hydroxy-Fatty Acid Metabolites of Arachidonic Acid by Methyl Ester Derivatives  

PubMed Central

The human polymorphonuclear (PMN) leukocyte chemotactic activity of the hydroxy-fatty acid metabolites of arachidonic acid, 12-l-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and 12-l-hydroxy-5,8,10,14-eicosatetraenoic acid (HETE), is eliminated by methylation. Both methyl esters are specific competitive inhibitors of the PMN leukotactic responses to the parent stimuli, and exert no effect on the responses to formyl-methionyl peptides or chemotactic fragments of the fifth component of complement. 50% inhibition of the in vitro chemotactic responses of PMN leukocytes to HETE and HHT was achieved by an equimolar concentration of the corresponding methyl esters, whereas reciprocal cross-inhibition was observed at molar ratios of HETE methyl ester to HHT and HHT methyl ester to HETE which reflected the three- to fivefold greater chemotactic potency of HETE relative to HHT. Methyl esters of structurally related, but nonchemotactic, fatty acids did not competitively inhibit the chemotaxis elicited by HETE or HHT. The intraperitoneal injection of HETE in guinea pigs evoked an eosinophil response at 30 min and a neutrophil response at 5 h, which were prevented by a one-to twofold molar ratio of HETE methyl ester. The competitive inhibition of the in vitro chemotactic activity and the in vivo leukotactic effect of the unsaturated hydroxy-fatty acids by homologous methyl ester derivatives suggests that the cellular component of natural inflammatory reactions may be susceptible to specific regulation by receptor-directed modulation of the activity of the predominant chemotactic principles.

Goetzl, Edward J.; Valone, Frank H.; Reinhold, Vernon N.; Gorman, Robert R.

1979-01-01

306

Synthesis and immunomodulatory activites of new 5-hydrazino-3-methyl-4-isothiazolecarboxylic acid ethyl esters.  

PubMed

Several new derivatives of 5-hydrazino-3-methyl-4-isothiazolecarboxylic ethyl esters were synthesized. Using 4-aminoacetophenone, the hydrazine group was transformed in position 5 in the hydrazone which reacted with the isocyanates, aldehydes and sugars. Thirteen newly synthesized compounds were tested for their ability to affects the immunological response in vitro in several rodent models. The immunoregulatory properties of the compounds were differential and dose-dependent. The strongest activity was exhibited by 5-{N'-[1-4{-4-[3-(-methoxyphenyl)-ureidol]-phenylethylidene]-hydrazino}-3-methyl-4-isothiazolecarboxylic acid ethyl ester (compound 3a). The compound strongly inhibited the secondary, humoral immune response to sheep erythrocytes and the proliferative response of mouse splenocytes to concanavalin A and pokeweed mitogen. The immunotropic activities of the new isothiazole derivatives and potential application of the compounds in therapy are discussed. PMID:19894646

Lipnicka, Urszula; Maczy?ski, Marcin; Artym, Jolanta; Zimecki, Micha?

2009-01-01

307

Fumaric acid esters are effective in chronic experimental autoimmune encephalomyelitis and suppress macrophage infiltration  

PubMed Central

Fumaric acid esters (FAE) have proven their therapeutic efficacy in psoriasis, a Th1 mediated skin disease. More recently, preliminary data have suggested an activity in multiple sclerosis (MS) as well. To investigate further possible mechanisms of action of these compounds in inflammatory diseases, we studied the FAE methyl hydrogen fumarate (MHF) and dimethyl fumarate (DMF) in chronic experimental autoimmune encephalomyelitis (EAE) induced by immunization of C57BL/6 mice with MOG peptide aa 3555. Preventive treatment with these FAE was delivered twice a day by oral gavage. Both esters had a significant therapeutic effect on the disease course and histology showed a strongly reduced macrophage inflammation in the spinal cord. Multiparameter cytokine analysis from blood detected an increase of IL-10 in the treated animals. We conclude that the underlying biological activity of FAE in EAE is complex and, to elucidate the molecular mechanisms, further investigation is needed.

Schilling, S; Goelz, S; Linker, R; Luehder, F; Gold, R

2006-01-01

308

FATTY ACID METHYL ESTER (FAME) TECHNOLOGY FOR MONITORING BIOLOGICAL FOAMING IN ACIVATED SLUDGE: FULL SCALE PLANT VERIFICATION  

Microsoft Academic Search

Fatty acid methyl ester (FAME) technology was evaluated as a monitoring tool for quantification of Gordonia amarae in activated sludge systems. The fatty acid, 19:1 alcohol, which was identified as a unique fatty acid in G. amarae was not only confirmed to be present in foaming plant samples, but the quantity of the signature peak correlated closely with the degree

J. W. Lee; D. K. Cha; I. Kim; A. Son; K. H. Ahn

2008-01-01

309

21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...  

Code of Federal Regulations, 2013 CFR

...tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582...tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty acids....

2013-04-01

310

40 CFR 721.10289 - Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic).  

Code of Federal Regulations, 2013 CFR

...polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). 721...polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). (a...polymer with aliphatic polyol dihydrogen phosphate aromatic ester (PMN...

2013-07-01

311

Characterization of Benthic Microbial Community Structure by High-Resolution Gas Chromatography of Fatty Acid Methyl Esters  

PubMed Central

Fatty acids are a widely studied group of lipids of sufficient taxonomic diversity to be useful in defining microbial community structure. The extraordinary resolution of glass capillary gas-liquid chromatography can be utilized to separate and tentatively identify large numbers of fatty acid methyl esters derived from the lipids of estuarine detritus and marine benthic microbiota without the bias of selective methods requiring culture or recovery of the microbes. The gas-liquid chromatographic analyses are both reproducible and highly sensitive, and the recovery of fatty acids is quantitative. The analyses can be automated, and the diagnostic technique of mass spectral fragmentation analysis can be readily applied. Splitless injection on glass capillary gas chromatographic columns detected by mass spectral selective ion monitoring provides an ultrasensitive and definitive monitoring system. Reciprocal mixtures of bacteria and fungi, when extracted and analyzed, showed progressive changes of distinctive fatty acid methyl esters derived from the lipids. By manipulating the environment of an estuarine detrital microbial community with antibiotics and culture conditions, it was possible to produce a community greatly enriched in eucaryotic fungi, as evidenced by scanning electron microscopic morphology. The fatty acid methyl esters from the lipids in the fungus-enriched detritus showed enrichment of the C18 dienoic and the C18 and C20 polyenoic esters. Manipulation of the detrital microbiota that increased the procaryotic population resulted in an absence of large structures typical of fungal mycelia or diatoms, as evidenced by scanning electron microscopy, and a significantly larger proportion of anteiso- and isobranched C15 fatty acid esters, C17 cyclopropane fatty acid esters, and the cis-vaccenic isomer of the C18 monoenoic fatty acid esters. As determined by these techniques, a marine settling community showed greater differences in bacterial as contrasted to microeucaryotic populations when compared with the microbial communities of benthic cores. Images

Bobbie, Ronald J.; White, David C.

1980-01-01

312

In vivo degradation and elimination of injectable ricinoleic acid-based poly(ester-anhydride).  

PubMed

The in vivo degradation and elimination after subcutaneous implantation of injectable p(SA-RA) 3:7 copolymer in rats, followed by characterization of the polymer matrix composition during hydrolysis and erosion, is reported. Major chemical changes were observed during the first few days post implantation, the anhydride bonds hydrolyzed along with about 45% weight loss and a significant decrease in the molecular weight. 1H NMR spectral analysis was used to determine the structures and content of ricinoleic acid containing oligomeric chains present in the degraded polymer. The polymer degrades into ester oligomers of 2-4 ricinoleic acid units which further degrade to ricinoleic acid, a natural fatty acid. The polymer hydrolytic degradation process fit the in vitro degradation process. PMID:23530926

Vaisman, Boris; Ickowicz, Diana E; Abtew, Ester; Haim-Zada, Moran; Shikanov, Ariella; Domb, Abraham J

2013-05-13

313

Simultaneous analysis of low plasma levels of deuterium-labeled saturated and unsaturated fatty acids as t-butyldimethylsilyl esters  

SciTech Connect

A sensitive and accurate method for detection and quantitation of deuterated fatty acids in the presence of large amounts of unlabeled fatty acids is described using mass fragmentography in combination with the preparation of tertiarybutyldimethylsilyl esters (t-BDMS). The method has been applied to determination of deuterated stearic, oleic, elaidic and linoleic acids in human plasma lipoproteins following duodenal perfusion with a micellar mixture of acids. Over a concentration range of 10-1000 ng/ml, the average coefficient of variation for the linoleate was 3% and for the oleate (elaidate) ester was 2%.

Parsons, H.; Emken, E.M.; Marai, L.; Kuksis, A.

1986-03-01

314

Studies of the acidic components of the Colorado Green River formation oil shale-Mass spectrometric identification of the methyl esters of extractable acids.  

NASA Technical Reports Server (NTRS)

Study of solvent extractable acidic constituents of oil shale from the Colorado Green River Formation. Identification of individual components is based on gas chromatographic and mass spectrometric data obtained for their respective methyl esters. Normal acids, isoprenoidal acids, alpha, omega-dicarboxylic acids, mono-alpha-methyl dicarboxylic acids and methyl ketoacids were identified. In addition, the presence of monocyclic, benzoic, phenylalkanoic and naphthyl-carboxylic acids, as well as cycloaromatic acids, is demonstrated by partial identification.

Haug, P.; Schnoes, H. K.; Burlingame, A. L.

1971-01-01

315

Antiandrogenic activity of anthranilic acid ester derivatives as novel lead structures to inhibit prostate cancer cell proliferation.  

PubMed

A plant extract from the fruits of saw palmetto, which is currently used to treat the androgen-dependent benign prostatic hyperplasia and PCa, served as source for new structure variants. We investigated the antiandrogenic potential of an ethanolic total extract and one of its main aromatic components anthranilic acid. An androgen receptor-antagonistic (antiandrogenic) effect of the extract was evident, and although anthranilic acid itself revealed no remarkable effect, its methyl ester, methyl anthranilate, exhibited antiandrogenic potential. Based on this chemical structure, we synthesized and investigated the antiandrogenic activity of four AnA ester derivatives, which were either novel or only little described in literature. These AnA esters inhibit the androgen-dependent transactivation of both the wild-type (wt) androgen receptor and the androgen receptor point mutant T877A, which often occurs in refractory PCa. Moreover, they inhibit the androgen receptor-induced expression of the endogenous prostate-specific antigen. Importantly, AnA esters repress the growth of human PCa cells. Deletion analyses of androgen receptor propose that the antiandrogenic effect of anthranilic acid esters is mediated by the ligand-binding domain, most likely through direct binding, without affecting androgen receptor protein levels. Taken together, the data suggest antiandrogenic potential of anthranilic acid ester derivatives, which can serve as lead structures for novel antiandrogens. PMID:21439024

Roell, Daniela; Rsler, Thomas W; Degen, Stephanie; Matusch, Rudolf; Baniahmad, Aria

2011-06-01

316

QTL for phytosterol and sinapate ester content in Brassica napus L. collocate with the two erucic acid genes  

PubMed Central

Improving oil and protein quality for food and feed purposes is an important goal in rapeseed (Brassica napus L.) breeding programs. Rapeseed contains phytosterols, used to enrich food products, and sinapate esters, which are limiting the utilization of rapeseed proteins in the feed industry. Increasing the phytosterol content of oil and lowering sinapate ester content of meal could increase the value of the oilseed rape crop. The objective of the present study was to identify quantitative trait loci (QTL) for phytosterol and sinapate ester content in a winter rapeseed population of 148 doubled haploid lines, previously found to have a large variation for these two traits. This population also segregated for the two erucic acid genes. A close negative correlation was found between erucic acid and phytosterol content (Spearmans rank correlation, rs=?0.80**). For total phytosterol content, three QTL were detected, explaining 60% of the genetic variance. The two QTL with the strongest additive effects were mapped on linkage groups N8 and N13 within the confidence intervals of the two erucic acid genes. For sinapate ester content four QTL were detected, explaining 53% of the genetic variance. Again, a close negative correlation was found between erucic acid and sinapate ester content (rs=?0.66**) and the QTL with the strongest additive effects mapped on linkage groups N8 and N13 within the confidence intervals of the two erucic acid genes. The results suggests, that there is a pleiotropic effect of the two erucic acid genes on phytosterol and sinapate ester content; the effect of the alleles for low erucic acid content is to increase phytosterol and sinapate ester content. Possible reasons for this are discussed based on known biosynthetic pathways. Electronic supplementary material The online version of this article (doi:10.1007/s00122-008-0734-2) contains supplementary material, which is available to authorized users.

Amar, Samija; Ecke, Wolfgang; Becker, Heiko C.

2008-01-01

317

Electronically Rich N-Substituted Tetrahydroisoquinoline 3-Carboxylic Acid Esters: Concise Synthesis and Conformational Studies  

PubMed Central

Recent work in our laboratory has shown that the highly substituted, electronically rich 1,2,3,4tetrahydroisoquinoline3carboxylic acid (THIQ3CA) scaffold is a key building block for a novel class of promising anticoagulants (Al-Horani et al. J. Med. Chem. 2011, 54, 61256138). The synthesis of THIQ3CA analogs, especially containing specific, electronically rich substituents, has been a challenge and essentially no efficient methods have been reported in the literature. We describe three complementary, glycine donor-based strategies for high yielding synthesis of highly substituted, electronically rich THIQ3CA esters. Three glycine donors studied herein include hydantoin 1, ()-Boc-?-phosphonoglycine trimethyl ester 2 and ()-Z-?-phosphonoglycine trimethyl ester 3. Although the synthesis of THIQ3CA analogs could be achieved using either of the three, an optimal, high yielding approach for the desired THIQ3CA esters was best achieved using 3 in three mild, efficient steps. Using this approach, a focused library of advanced N-arylacyl, N-arylalkyl, and bis-THIQ3CA analogs was synthesized. Variable temperature and solvent-dependent NMR chemical shift studies indicated the presence of two major conformational rotamers in 3:1 proportion for NarylacylTHIQ3CA analogs, which were separated by a high kinetic barrier of ~17 kcal/mol. In contrast, Narylalkyl and bisTHIQ3CA variants displayed no rotamerism, which implicates restricted rotation around the amide bond as the origin for high-barrier conformational interconversion. This phenomenon is of major significance because structure-based drug design typically utilizes only one conformation. Overall, the work presents fundamental studies on the synthesis and conformational properties of highly substituted, electronically rich THIQ3CA analogs.

Al-Horani, Rami A.; Desai, Umesh R.

2012-01-01

318

Synthesis and characterization of phosphonate ester and phosphonic acid containing polymers and blends  

NASA Astrophysics Data System (ADS)

Vinylbenzylphosphonate ester (VBP) was homopolymerized and copolymerized with methyl methacrylate and the reactivity ratio of this pair of monomers was calculated from Finneman-Ross and Kelen-Tudos methods. These methods provided identical values, which are rsb1 (VBP) = 1.23 and rsb2(MMA) = 0.43. The phosphonate ester group, -P = O(OEt)sb2; in VBP and poly(VBP-MMA) copolymers was hydrolysed to phosphonic acid, -P = O(OH)sb2; at room temperature to obtain vinylbenzylphosphonic acid (VBPa) and poly(VBPa-MMA) copolymers. sp1H, sp{13}C & sp{31}P NMR spectroscopy, DSC and FTIR were used to monitor the hydrolysis of these phosphorylated monomers and polymers. The glass transition temperature of PVBP was 13spC as compared to 198spC of PVBPa. The phosphoryl group in the parent polymers acts as a self plasticizing agent resulting in lower glass transition temperature, on the other hand inter and intra hydrogen bonding results in broad and high Tsbg in these hydrolysed polymers. VBP was also polymerized with BisGMA or TEGDM to low conversions. These oligomers were tested in vitro as potential adhesive materials for dental/enamel and composite resins. The phosphonate esters containing polymers show substantial capacity to dissolve the heavy metal salts, e.g., UOsb2(NO)sb3.6Hsb2O and thus provides radiopaque polymers. Excessive sorption of water lead to phase separation and, hence, loss of radiopacity. Thus, an alternate method of synthesis of radiopaque polymers is also described in which radiopacifying agent is covalently linked to polymer backbone. Styryldiphenylbismuth was prepared by the reaction of diphenylbismuthchloride and Grignard of p-bromostyrene, but some other by-products such as triphenylbismuth, distyrylphenyl bismoth were also obtained as revealed by reverse phase HPLC and the yield of the reaction was low. Iodinated monomers VBTIsb3 and IEMIsb3 were prepared by reacting VBC or IEM to triiodophenol in high yields. Decomposition kinetic analysis was done by TGA to estimate the thermal stability of iodinated polymers. Incorporation of 13 wt% of either monomer in MMA or VBP results in radiopacity equivalent to 2 mm of aluminum a standard used in dentistry. Finally the dimethyl vinylphosphonate ester was homopolymerized and copolymerized with VBP. The aliphatic phosphonate ester was blended with cellulose acetate and cellulose acetate butyrate. The crystallinity of CA was completely impeded when 5 wt% of PDMVP was added, and the Flory interaction parameter chi obtained for PDMVP/CA was large and negative indicating a strong interaction between this pair of polymers.

Tamber, Harinder Singh

1997-12-01

319

4Hydroxy3-methyl-6-phenylbenzofuran-2-carboxylic acid ethyl ester derivatives as potent anti-tumor agents  

Microsoft Academic Search

Based on the structure of 4-hydroxy-3-methyl-6-phenylbenzofuran-2-carboxylic acid ethyl ester (1), which exhibits selective cytotoxicity against a tumorigenic cell line, (2,4-dimethoxyphenyl)-(4-hydroxy-3-methyl-6-phenylbenzofuran-2-yl)-methanone (18m) was designed and synthesized as a biologically stable derivative containing no ester group. Although the potency of 18m was almost the same as our initial hit compound 1, 18m is expected to last longer in the human body as

Ichiro Hayakawa; Rieko Shioya; Toshinori Agatsuma; Hidehiko Furukawa; Shunji Naruto; Yuichi Sugano

2004-01-01

320

Synthesis and antitumor activity of amino acid ester derivatives containing 5-fluorouracil.  

PubMed

A series of amino acid ester derivatives containing 5-fluorouracil were synthesized using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC*HCl) and N-hydroxybenzotriazole (HOBt) as a coupling agent. The structures of the products were assigned by NMR, MS, IR etc. The in vitro antitumor activity tests against leukaemia HL-60 and liver cancer BEL-7402 indicated that (R)-ethyl 2-(2-(5-fluoro-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamido)-3-(4-hydroxyphenyl) propanoate showed more inhibitory effect against BEL-7402 than 5-FU. PMID:19783913

Xiong, Jing; Zhu, Hai-Feng; Zhao, Ya-Juan; Lan, Yun-Jun; Jiang, Ji-Wang; Yang, Jing-Jing; Zhang, Shu-Feng

2009-01-01

321

Salicylanilide esters of N-protected amino acids as novel antimicrobial agents.  

PubMed

A series of novel, highly antimicrobial salicylanilide esters of N-protected amino acids were synthesized and characterized. Their in vitro antimicrobial activity against eight fungal strains and Mycobacterium tuberculosis was determined. The compounds had the highest level of activity against Aspergillus fumigatus, Absidia corymbifera and Trichophyton mentagrophytes, and these levels were higher than that of the standard drug fluconazole. In addition, three compounds showed interesting antituberculosis activity, with inhibition ranging from 89% to 99%. (S)-4-Chloro-2-(4-trifluoromethylphenylcarbamoyl)-phenyl 2-benzyloxy-carbonylamino-propionate had the highest level of both antifungal and antimycobacterial activity. The structure-activity relationships of the new compounds are discussed. PMID:19081718

Imramovsk, Ales; Vinsov, Jarmila; Frriz, Juana Monreal; Buchta, Vladimr; Jamplek, Josef

2009-01-15

322

LC50 values for rats acutely exposed to vapors of acrylic and methacrylic acid esters  

SciTech Connect

Acute exposure studies were conducted using adult male Sprague-Dawley rats to obtain LC50/24 concentrations for the common esters of acrylic and methacrylic acids. The order of acute toxicity was determined to be methyl acrylate > ethyl acrylate > butyl acrylate > butyl methacrylate > methyl methacrylate > ethyl methacrylate. Four-hour daily exposures (excluding weekends) of young adult male rats to 110 ppm methyl acrylate in air over a period of 32 d failed to produce significant differences in body or tissue weights, blood chemistries, gross metabolic performance, and spontaneous small-intestinal motor activities when compared with a sham-exposed group.

Oberly, R.; Tansy, M.F.

1985-01-01

323

Molecular Model of trans-3-(9-Anthryl)-2-Propenoic Acid Ethyl Ester  

NSDL National Science Digital Library

The Featured Molecules this month come from the paper by Nguyen and Weisman on solvent-free Wittig reactions and the stereochemical consequences of crowding in the transition state. The molecules include those pictured in the paper as well as the cis-isomer of 3-(9-anthryl)-2-propenoic acid ethyl ester. All structures were optimized at the B3LPY/6-31G* level. In the case of ethyl cinnamate, the cis-isomer is slightly more stable thermodynamically than the trans isomer, lending further support for the argument that the observed product distribution arises from the energetics of the transition state.

324

Metastable McLafferty rearrangement reaction in the electron impact ionization of stearic acid methyl ester  

NASA Astrophysics Data System (ADS)

The metastable peaks for the McLafferty rearrangement and double hydrogen rearrangement reactions have been observed in the stearic acid methyl ester system under electron impact ionization. The metastable ion spectrum of the M+. ion gave peaks corresponding to the ions at m/z 74, 75, 87 and 88, whereas the collision-induced dissociation spectrum showed low intensity ions at m/z 75 and 88 which come from double hydrogen rearrangement reactions of M+. ions. The kinetics for the change of the molecular ions to different structures before fragmentation have been discussed.

Takayama, Mitsuo

1995-06-01

325

The reaction of nonconjugated unsaturated fatty acid esters with maleic anhydride  

Microsoft Academic Search

Summary1. The non-conjugated unsaturated fatty acid esters react with maleic anhydride at 200 C. or above.\\u000a \\u000a 2. At 200 C., methyl oleate reacts with almost 1 mole, methyl linoleate with 2 moles, and methyl linolenate with 2.5 moles\\u000a of maleic anhydride, when an excess of anhydride is present. Methyl stearate reacts negligibly.\\u000a \\u000a \\u000a \\u000a 3. Methyl oleate reacts without affecting unsaturation.\\u000a \\u000a \\u000a 4.

W. G. Bickford; P. Krauczunas; D. H. Wheeler

1942-01-01

326

Malignant melanoma during treatment with fumaric acid esters - coincidence or treatment-related?  

PubMed

Psoriasis is today generally considered a systemic disease. Systemic therapies are used frequently. In Germany fumaric acid esters - FAE (Fumaderm() ) - are employed in more than 50 % of the patients requiring such therapy. We report for the first time the development of melanoma in two patients during their treatment with FAE. The logical question is - are the tumors coincidental or might they be treatment-related? Further investigations of pathways and immunologic effects as well as careful reports of side effects are necessary to estimate the risks of malignancy of FAE. PMID:20678147

Barth, Dietrich; Simon, Jan C; Wetzig, Tino

2011-03-01

327

Fatty acid ethyl esters, nonoxidative ethanol metabolites, synthesis, uptake, and hydrolysis by human platelets.  

PubMed

The consumption of alcohol is known to have both positive and negative effects on the functioning of the cardiovascular system in general, and on platelet function in particular. Fatty acid ethyl esters (FAEEs) are non-oxidative metabolite of ethanol that may mediate the ethanol effect on platelet function leading to either bleeding or clotting. The aim of the current study was to investigate the synthesis, uptake, and hydrolysis of FAEEs by human platelets. Isolated platelets were incubated with ethanol for various times, and FAEE synthesis were measured by gas chromatography mass-spectrometry (GC-MS). In addition, platelets were incubated with (14)C-ethyl oleate, and FAEE uptake and hydrolysis were measured. There was significant synthesis of FAEEs by human platelets within 30 min of exposure to ethanol. The major FAEE species formed by human platelets exposed to ethanol were ethyl palmitate and ethyl stearate. FAEE uptake by human platelets showed maximum uptake by 60 s. The majority of FAEEs (50-80%) incorporated into platelets remained intact for up to 10 min. FAEE hydrolysis led to an increase in free fatty acids, with minimal subsequent esterification of the free fatty acids into phospholipids, triglycerides, and cholesterol esters. These studies show that FAEEs, non-oxidative metabolite of ethanol, can be incorporated into, synthesized, and hydrolyzed by human platelets. PMID:16325465

Salem, Raneem O; Cluette-Brown, Joanne E; Laposata, Michael

2005-12-30

328

Influence of fatty acid methyl esters from hydroxylated vegetable oils on diesel fuel lubricity.  

PubMed

Current and future regulations on the sulfur content of diesel fuel have led to a decrease in lubricity of these fuels. This decreased lubricity poses a significant problem as it may lead to wear and damage of diesel engines, primarily fuel injection systems. Vegetable oil based diesel fuel substitutes (biodiesel) have been shown to be clean and effective and may increase overall lubricity when added to diesel fuel at nominally low levels. Previous studies on castor oil suggest that its uniquely high level of the hydroxy fatty acid ricinoleic acid may impart increased lubricity to the oil and its derivatives as compared to other vegetable oils. Likewise, the developing oilseed Lesquerella may also increase diesel lubricity through its unique hydroxy fatty acid composition. This study examines the effect of castor and Lesquerella oil esters on the lubricity of diesel fuel using the High-Frequency Reciprocating Rig (HFRR) test and compares these results to those for the commercial vegetable oil derivatives soybean and rapeseed methyl esters. PMID:15607199

Goodrum, John W; Geller, Daniel P

2005-05-01

329

Diarrhetic shellfish poisoning by okadaic acid esters from Brown crabs (Cancer pagurus) in Norway.  

PubMed

In 2002 several hundred people were taken ill after eating self-harvested brown crabs (Cancer pagurus) in the southern part of Norway. The symptoms were similar to diarrhetic shellfish poisoning (DSP) although with a somewhat delayed onset. This happened at the same time as an unusual early bloom of Dinophysis acuta had lead to high amounts of DSP toxins in blue mussels (Mytilus edulis) in the same area. The proposed cause of the intoxication was that crabs had accumulated toxins by eating blue mussels. Analyses of crab material from the area revealed very little free toxin in the form of okadaic acid (OA). However, after alkaline hydrolysis of the material, the amounts of OA found in the crabs were above the toxic level. MS/MS analysis of a sample from one intoxication episode indicated presence of the 14:0, 16:1, 16:0 and 18:1 fatty acid esters of okadaic acid. Esterified OA constituted more than 90% of total identified DSP toxins in crabs, indicating that not only esterified toxin from mussels was accumulated, but also that appreciable transfer of OA to OA-esters occurred in the crabs. PMID:16153454

Torgersen, Trine; Aasen, John; Aune, Tore

2005-10-01

330

Acridinyl methyl esters as photoactive precursors in the release of neurotransmitter amino acids.  

PubMed

An investigation of the use of an azaheterocycle, acridine, as an alternative photochemically removable protecting group for the carboxylic function of neurotransmitter amino acids was carried out. 9-Bromomethylacridine was used in the reaction with glycine, alanine, glutamic acid, ?-alanine and ?-aminobutyric acid, to obtain model ester derivatives, which were irradiated at different wavelengths in a photochemical reactor. The process was followed by HPLC/UV, resulting in the release of the active molecule in short irradiation times. The results obtained using 419 nm irradiation show promise (35-98 min) for practical purposes. The compounds were further characterised via time-resolved fluorescence to elucidate their photophysical properties and determine the decay kinetics. PMID:23064410

Piloto, Ana M; Hungerford, Graham; Costa, Susana P G; Gonalves, M Sameiro T

2013-02-01

331

An efficient preparation of N-methyl-alpha-amino acids from N-nosyl-alpha-amino acid phenacyl esters.  

PubMed

In this paper we describe a simple and efficient solution-phase synthesis of N-methyl-N-nosyl-alpha-amino acids and N-Fmoc-N-methyl-alpha-amino acids. This represents a very important application in peptide synthesis to obtain N-methylated peptides in both solution and solid phase. The developed methodology involves the use of N-nosyl-alpha-amino acids with the carboxyl function protected as a phenacyl ester and the methylating reagent diazomethane. An important aspect of this synthetic strategy is the possibility to selectively deprotect the carboxyl function or alternatively both amino and carboxyl moieties by using the same reagent with a different molar excess and under mild conditions. Furthermore, the adopted procedure keeps unchanged the acid-sensitive side chain protecting groups used in Fmoc-based synthetic strategies. PMID:20121053

Leggio, Antonella; Belsito, Emilia Lucia; De Marco, Rosaria; Liguori, Angelo; Perri, Francesca; Viscomi, Maria Caterina

2010-03-01

332

Effects of supplementation with 2-hydroxy-4-(methylthio)-butanoic acid isopropyl ester on splanchnic amino acid metabolism and essential amino acid mobilization in postpartum transition Holstein cows  

Microsoft Academic Search

The present study aimed to investigate the effects of 2-hydroxy-4-(methylthio)-butanoic acid isopropyl ester (HMBi) supplementation on splanchnic AA metabolism, essential AA (EAA) mobilization, and plasma AA status in postpartum transition dairy cows. The EAA mobilization was calculated by difference: EAA excretion in milk protein ? net portal absorption of EAA or net splanchnic release of EAA. Eight Holstein cows fitted

K. F. Dalbach; M. Larsen; B. M. L. Raun; N. B. Kristensen

2011-01-01

333

Subtype-selective inhibition of [methyl-3H]-N-methylscopolamine binding to muscarinic receptors by ?-truxillic acid esters  

PubMed Central

Seven esters of ?-truxillic acid have been synthesized: bis-3-piperidylpropyl ester and its quaternary bis-N-ethyl derivative, bis-N-diethylaminopropyl ester and its quaternary bis-N-methyl derivative, and bis-4-piperidylbutyl ester and its quaternary bis-N-methyl and bis-N-ethyl derivatives. All esters inhibited the specific binding of muscarinic receptor antagonist [methyl-3H]-N-methylscopolamine ([3H]-NMS) to muscarinic receptors in membranes of CHO cell lines stably expressing the human gene for the M1, M2, M3 or M4 subtype of muscarinic receptors. All esters displayed the highest potency at the M2 and the lowest potency at the M3 receptor subtype. In experiments performed on the M2 muscarinic receptor subtype, the affinity between the receptors and the esters was greatly increased when the concentration of ions was diminished. The highest affinities were found for the tertiary bis-3-piperidylpropyl and bis-4-piperidylbutyl aminoesters (equilibrium dissociation constants of 52 and 179?pM, respectively, in the low ionic strength medium). All investigated esters slowed down the dissociation of [3H]-NMS from the M2 muscarinic receptor subtype. [3H]-NMS dissociation from the M1, M3 and M4 muscarinic receptor subtypes was investigated in experiments with the bis-4-piperidylbutyl aminoester and also found to be decelerated. It is concluded that the esters of ?-truxillic acid act as M2-selective allosteric modulators of muscarinic receptors and that, by their potency, the tertiary bis-3-piperidylpropyl and bis-4-piperidylbutyl aminoesters surpass the other known allosteric modulators of these receptors.

Lysikova, Michaela; Fuksova, Kveta; Elbert, Tomas; Jakubik, Jan; Tucek, Stanislav

1999-01-01

334

N-alkanes, fatty acid esters, and fatty acid salts in size fractionated aerosols collected over the Mediterranean Sea  

SciTech Connect

The {und n}-alkanes, fatty acid esters, and fatty acid salts have been analyzed in size fractionated aerosols collected over the Mediterranean Sea using a five-stage cascade impactor. Two main sources of {und n}-alkanes have been identified: terrestrially derived {und n}-alkanes evenly distributed over the whole particle size spectrum and anthropogenic {und n}-alkanes predominantly carried by submicron particles. The comparison between the fatty acid ester (FAE) and fatty acid salt (FAS) particle size distributions allowed an important contribution to be ascertained of the marine source in aerosols ranging from 7.2 to 3.0 {mu}m under rough weather conditions that may be due to larger bubble produced particles. In contrast, FAE and FAS were evenly distributed from the first to the fifth stage, when collected during calm sea surface conditions. Higher values of the degree of unsaturation of FAE and FAS were associated with mass concentration maxima observed on stages 2 and 3 in IMP1 aerosol sample whereas lower values were found on the other stages in the same sample, and over the whole particle size spectrum in IMP2 aerosol sample collected during calm weather conditions. The data the authors present here are discussed in terms of jet and film drop ejections and degradation processes.

Sicre, M.A.; Marty, J.C.; Saliot, A. (Univ. Pierre et Marie Curie, Paris (France))

1990-03-20

335

Phosphoric acid esters cannot replace polyvinylphosphonic acid as phosphoprotein analogs in biomimetic remineralization of resin-bonded dentin  

PubMed Central

Polyvinylphosphonic acid (PVPA), a biomimetic analog of phosphoproteins, is crucial for recruiting polyacrylic acid (PAA)-stabilized amorphous calcium phosphate nanoprecursors during biomimetic remineralization of dentin collagen matrices. This study tested the null hypothesis that phosphoric acid esters of methacrylates in dentin adhesives cannot replace PVPA during bimimetic remineralization of resin-dentin interfaces. Human dentin specimens were bonded with: I) XP Bond, an etch-and-rinse adhesive using moist bonding; II) XP Bond using dry bonding; and III) Adper Prompt L-Pop, a self-etching adhesive. The control medium contained only set Portland cement and a simulated body fluid (SBF) without any biomimetic analog. Two experimental Portland cement/SBF remineralization media were evaluated: the first contained PAA as the sole biomimetic analog, the second contained PAA and PVPA as dual biomimetic analogs. No remineralization of the resin-dentin interfaces could be identified from specimens immersed in the control medium. After 24 months in the first experimental medium, specimens exhibited either no remineralization or large crystal formation within hybrid layers. Only specimens immersed in the second remineralization medium produced nanocrystals that accounted for intrafibrillar remineralization within hybrid layers. The null hypothesis could not be rejected; phosphoric acid esters in dentin adhesives cannot replace PVPA during biomimetic remineralization of adhesive-bonded dentin.

Mai, Sui; Kim, Young Kyung; Toledano, Manuel; Breschi, Lorenzo; Ling, Jun Qi; Pashley, David H.; Tay, Franklin R.

2009-01-01

336

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Boric acid (H3BO3), mixed esters with polyethylene...Chemical Substances § 721.1729 Boric acid (H3BO3), mixed esters with polyethylene...chemical substance identified as boric acid (H3 BO3 ), mixed...

2010-07-01

337

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Boric acid (H3BO3), mixed esters with polyethylene...Chemical Substances § 721.1729 Boric acid (H3BO3), mixed esters with polyethylene...chemical substance identified as boric acid (H3 BO3 ), mixed...

2009-07-01

338

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Boric acid (H3BO3), mixed esters with polyethylene...Chemical Substances § 721.1729 Boric acid (H3 BO3 ), mixed esters with...chemical substance identified as boric acid (H3 BO3 ), mixed...

2013-07-01

339

Preparation of stearoyl lactic acid ester catalyzed by lipases from Rhizomucor miehei and porcine pancreas optimization using response surface methodology  

Microsoft Academic Search

The esterification reaction between stearic acid and lactic acid using Rhizomucor miehei lipase and porcine pancreas lipase was optimized for maximum esterification using response surface methodology. The formation\\u000a of the ester was found to depend on three parameters namely enzyme\\/substrate ratio, lactic acid (stearic acid) concentration\\u000a and incubation period. The maximum esterification predicted by theoretical equations for both lipases matched

K. R. Kiran; N. G. Karanth; S. Divakar

1999-01-01

340

Fatty acid esters of 3-chloropropane-1,2-diol in edible oils.  

PubMed

A series of 25 virgin and refined edible oils, obtained from retailers, was analyzed for levels of free 3-chloropropane-1,2-diol (3-MCPD) and 3-MCPD released from esters with higher fatty acids (bound 3-MCPD). Oils containing free 3-MCPD ranging from <3 microg kg-1 (LOD) to 24 microg kg-1. Surprisingly, bound 3-MCPD levels were much higher and varied between <100 (LOD) and 2462 microg kg-1. On average, virgin oils had relatively low levels of bound 3-MCPD, ranging from <100 (LOD) to <300 microg kg-1 (LOQ). Higher levels of bound 3-MCPD were found in oils from roasted oilseeds (337 microg kg-1) and in the majority of refined oils (<300-2462 microg kg-1), including refined olive oils. In general, it appears that the formation of bound 3-MCPD in oils is linked to preliminary heat treatment of oilseeds and to the process of oil refining. Analysis of unrefined, de-gummed, bleached, and deodorized rapeseed oil showed that the level of bound MCPD decreased during the refining process. However, additional heating of seed oils for 30 min at temperatures ranging from 100 to 280 degrees C, and heating at 230 degrees C (260 degrees C) for up to 8 h, led to an increase in bound 3-MCPD levels. On the other hand, heating of olive oil resulted in a decrease in bound 3-MCPD levels. For comparison, fat isolated from salami was analyzed for intact fatty acid esters of 3-MCPD. This fat contained bound 3-MCPD at a level of 1670 microg kg-1 and the fatty acid esters of 3-MCPD mainly consisted of 3-MCPD diesters; monoesters of 3-MCPD were present in smaller amounts. The major types of 3-MCPD diesters (about 85%) were mixed diesters of palmitic acid with C18 fatty acids (stearic, oleic, linoleic acids). These diesters were followed by 3-MCPD distearate (11%) and 3-MCPD dipalmitate (4%). Generally, very little 3-MCPD existed as the free compound (31 microg kg-1). PMID:17118872

Zelinkov, Z; Svejkovsk, B; Velsek, J; Dolezal, M

2006-12-01

341

Aberration of morphogenesis of siliceous frustule elements of the diatom Synedra acus in the presence of germanic acid.  

PubMed

Addition of germanic acid into the culture medium of the diatom Synedra acus subsp. radians (Kutz.) Skabitsch. had nearly no influence on the culture growth at the Ge/Si molar ratio 0.01, but stopped it at ratios 0.05 and higher. It was shown by mass-spectrometry that at the Ge/Si ratio 0.01 germanium was incorporated in both the cytoplasm and siliceous valves, whereas at Ge/Si 0.05 it was incorporated into the cytoplasm but almost failed to accumulate in the valves. At Ge/Si 0.1 germanium was accumulated in the cytoplasm, but its incorporation into the valves terminated. Studies on the cell morphology by light, epifluorescence, and transmission electron microscopy showed that high concentrations of germanic acid induced disorders in morphogenesis of the siliceous frustule and accumulation of large rhodamine-stainable electron-dense inclusions. Model chemical experiments with over-saturated solutions of silicic acid in the presence of polyallylamine revealed that addition of 5% germanic acid considerably accelerated coagulation of silica. Hence, the toxic effect of germanic acid on diatoms could be caused by changes in coagulation of silica. PMID:18205610

Safonova, T A; Annenkov, V V; Chebykin, E P; Danilovtseva, E N; Likhoshway, Ye V; Grachev, M A

2007-11-01

342

Comparison of acidic and alkaline catalysts for preparation of fatty acid methyl esters from ovine muscle with emphasis on conjugated linoleic acid  

Microsoft Academic Search

Methanolic reagents containing acidic catalysts, HCl (0.5 M, 1 h, 80 C) or BF3 (14%, 1 h, 80 C), or alkaline catalysts, KOH (0.2 M, 1560 min, 50 C) or NaOCH3 (0.5 M, 1560 min, 50 C), were compared for use in preparation of fatty acid methyl esters for GC analysis of total lipids from freeze-dried semitendinosus muscle of lambs

C. M. Murrieta; B. W. Hess; D. C. Rule

2003-01-01

343

Dynamic Analysis of Phorbol Esters in the Manufacturing Process of Fatty Acid Methyl Esters from Jatropha curcas Seed Oil  

Microsoft Academic Search

Jatropha curcas seed oil, which is unsuitable as an edible oil but has received attention as a novel vegetable fat and oil resource, contains\\u000a tumor-promoting phorbol esters. Currently, six types of derivatives of 12-deoxy-16-hydroxyphorbol (DHPEs) in J. curcas oil have been identified, and their toxicological safety for humans is being discussed. However, it is reported that most\\u000a DHPEs disappear during

Kosuke IchihashiDai; Dai Yuki; Hiroshi Kurokawa; Akinori Igarashi; Toshio Yajima; Masami Fujiwara; Katsuhiro Maeno; Shizuo Sekiguchi; Mitsuo Iwata; Hoyoku Nishino

2011-01-01

344

Synthesis and fungicidal activity of aryl carbamic acid-5-aryl-2-furanmethyl ester.  

PubMed

Chitin, a major structural component of insect cuticle and fungus cell wall but absent in plants and vertebrates, is regarded as a safe and selective target for pest control agents. Chitin synthesis inhibitors (CSIs) have been well-known as insect growth regulators (IGRs) but rarely found as fungicides in agriculture. To find novel CSIs with good activity, benzoylphenylurea, a typical kind of CSIs, was chosen as the lead compound and 26 novel aryl carbamic acid-5-aryl-2-furanmethyl esters were designed by converting the urea linkages of benzoylphenylureas to carbamic acid esters and changing the aniline parts into furanmethyl groups. The title compounds were synthesized and their structures confirmed by IR, (1)H NMR, and elemental analysis. Preliminary insecticidal and fungicidal bioassays were carried out. The results indicated that the title compounds had no insecticidal effect on Culex pipiens pallens and Plutella xylostella Linnaeus , but most compounds exhibited good fungicidal activities against Corynespora cassiicola , Thanatephorus cucumeris , Botrytis cinerea , and Fusarium oxysporum . In particular, compounds V-4, V-6, V-7, and V-8 showed better activities against the four strains than those of the commercialized fungicides. The morphologic result suggested that compound V-21 had disturbed the cell wall formation of C. cassiicola. The results indicated that modification on the urea linkage of benzoylphenylurea was an effective way to discover new candidates for fungicides. PMID:20151651

Li, Ying; Li, Bao-Ju; Ling, Yun; Miao, Hong-Jian; Shi, Yan-Xia; Yang, Xin-Ling

2010-03-10

345

Nonoxidative ethanol metabolism in human leukocytes: detection of fatty acid ethyl ester synthase activity.  

PubMed

Oxidative pathways of alcohol metabolism such as alcohol dehydrogenase usually are not present in human blood and therefore clinical studies correlating ethanol metabolism with alcohol abuse syndromes have not been performed. To assess the activity of nonoxidative ethanol metabolism in blood, we assayed for the activity of fatty acid ethyl ester synthase, a pathway recently described as abundant in the human organs most commonly damaged by alcohol. Indeed, peripheral human leukocytes contain detectable fatty acid ethyl ester synthase activity: 1.2 X 10(6) leukocytes from 10 ml blood catalyze the synthesis of ethyl oleate at 1.4 nmol/4 hr. The reaction is linear with respect to cell number and expended time; Km oleate = 600 microM, Km ethanol = 600 mM. DEAE cellulose chromatography partially purifies synthase activity into a minor and major form (activity ratio = 10/1). Thus, gene products exist in human blood that recognize ethanol and whose biological activity is conveniently assayable for clinical investigations of alcohol metabolism and abuse. PMID:3827909

Wright, M; Bieser, K J; Kinnunen, P M; Lange, L G

1987-02-13

346

Assessment of ionic liquid stationary phases for the GC analysis of fatty acid methyl esters.  

PubMed

The gas chromatographic separation of fatty acid methyl esters (FAMEs) on ionic liquid stationary phases was investigated. Seven commercially available ionic liquid columns were tested using a test mixture containing 37 fatty acid methyl esters. The influence of column temperature on the elution order was studied using five different temperature programs. Retention times were highly reproducible. Similar retention behavior was observed for the IL59, IL60, and IL61 columns. The peak pair C18:1 cis/trans was not baseline resolved on these columns, whose stationary phases are highly similar. C18:2 cis/trans, C18:3 n6/n3, and C20:3 n6/n3 were baseline separated on all columns. Baseline separation of the complete test mix was only obtained on the IL82 column using a heating rate of 5K/min. In general, retention times decreased with increasing column polarity but unsaturated FAMEs were retained stronger compared to their saturated counterparts. Except for the IL59 column, retention crossover was observed when the temperature program was changed. PMID:24965160

Dettmer, Katja

2014-08-01

347

3D Structure Modeling of Alpha-Amino Acid Ester Hydrolase from Xanthomonas rubrilineans  

PubMed Central

Alpha-amino acid ester hydrolase (EC 3.1.1.43, AEH) is a promising biocatalyst for the production of semi-synthetic ?-lactam antibiotics, penicillins and cephalosporins. The AEH gene from Xanthomonas rubrilineans (XrAEH) was recently cloned in this laboratory. The three-dimensional structure of XrAEH was simulated using the homology modeling method for rational design experiments. The analysis of the active site was performed, and its structure was specified. The key amino acid residues in the active site - the catalytic triad (Ser175, His341 and Asp308), oxyanion hole (Tyr83 and Tyr176), and carboxylate cluster (carboxylate groups of Asp209, Glu310 and Asp311) - were identified. It was shown that the optimal configuration of residues in the active site occurs with a negative net charge -1 in the carboxylate cluster. Docking of different substrates in the AEH active site was carried out, which allowed us to obtain structures of XrAEH complexes with the ampicillin, amoxicillin, cephalexin, D-phenylglycine, and 4-hydroxy-D-phenylglycine methyl ester. Modeling of XrAEH enzyme complexes with various substrates was used to show the structures for whose synthesis this enzyme will show the highest efficiency.

Zarubina, S.A.; Uporov, I.V.; Fedorchuk, E.A.; Fedorchuk, V.V.; Sklyarenko, A.V.; Yarotsky, S.V.; Tishkov, V.I.

2013-01-01

348

A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters  

PubMed Central

An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel.

Urban, Jiri; Svec, Frantisek; Frechet, Jean M.J.

2011-01-01

349

Dimer esters in ?-pinene secondary organic aerosol: effect of hydroxyl radical, ozone, relative humidity and aerosol acidity  

NASA Astrophysics Data System (ADS)

The formation of secondary organic aerosol (SOA) from both ozonolysis and hydroxyl radical (OH)-initiated oxidation of ?-pinene under conditions of high nitric oxide (NO) concentrations with varying relative humidity (RH) and aerosol acidity was investigated in the University of North Carolina dual outdoor smog chamber facility. SOA formation from ozonolysis of ?-pinene was enhanced relative to that from OH-initiated oxidation in the presence of initially high NO conditions. However, no effect of RH on SOA mass was evident. Ozone (O3)-initiated oxidation of ?-pinene in the presence of ammonium sulfate (AS) seed coated with organic aerosol from OH-initiated oxidation of ?-pinene showed reduced nucleation compared to ozonolysis in the presence of pure AS seed aerosol. The chemical composition of ?-pinene SOA was investigated by ultra-performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS), with a focus on the formation of carboxylic acids and high-molecular weight dimer esters. A total of eight carboxylic acids and four dimer esters were identified, constituting between 8 and 12% of the total ?-pinene SOA mass. OH-initiated oxidation of ?-pinene in the presence of nitrogen oxides (NOx) resulted in the formation of highly oxidized carboxylic acids, such as 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). The formation of dimer esters was observed only in SOA produced from the ozonolysis of ?-pinene in the absence of NOx, with increased concentrations by a~factor of two at higher RH (50-90%) relative to lower RH (30-50%). The increased formation of dimer esters correlates with an observed increase in new particle formation at higher RH due to nucleation. Increased aerosol acidity was found to have a negligible effect on the formation of the dimer esters. SOA mass yield did not influence the chemical composition of SOA formed from ?-pinene ozonolysis with respect to carboxylic acids and dimer esters. The results support the formation of the high-molecular weight dimer esters through gas-phase reactions of the stabilized Criegee Intermediate (sCI) formed from the ozonolysis of ?-pinene. The high molecular weight and polar nature of dimer esters formed in the gas-phase may explain increased particle number concentration as a~result of homogenous nucleation. Since three of these dimer esters (i.e., pinyl-diaterpenyl ester (MW 358), pinyl-diaterebyl ester (MW 344) and pinonyl-pinyl ester (MW 368)) have been observed in both laboratory-generated and ambient fine organic aerosol samples, we conclude that the dimer esters observed in this study can be used as tracers for the O3-initiated oxidation of ?-pinene, and are therefore indicative of enhanced anthropogenic activities, and that the high molecular weight and low volatility esters result in homogenous nucleation under laboratory conditions, increasing the particle number concentration.

Kristensen, K.; Cui, T.; Zhang, H.; Gold, A.; Glasius, M.; Surratt, J. D.

2013-12-01

350

Cloning, Sequence Analysis, and Expression in Escherichia coli of the Gene Encoding an ?-Amino Acid Ester Hydrolase from Acetobacter turbidans  

PubMed Central

The ?-amino acid ester hydrolase from Acetobacter turbidans ATCC 9325 is capable of hydrolyzing and synthesizing ?-lactam antibiotics, such as cephalexin and ampicillin. N-terminal amino acid sequencing of the purified ?-amino acid ester hydrolase allowed cloning and genetic characterization of the corresponding gene from an A. turbidans genomic library. The gene, designated aehA, encodes a polypeptide with a molecular weight of 72,000. Comparison of the determined N-terminal sequence and the deduced amino acid sequence indicated the presence of an N-terminal leader sequence of 40 amino acids. The aehA gene was subcloned in the pET9 expression plasmid and expressed in Escherichia coli. The recombinant protein was purified and found to be dimeric with subunits of 70 kDa. A sequence similarity search revealed 26% identity with a glutaryl 7-ACA acylase precursor from Bacillus laterosporus, but no homology was found with other known penicillin or cephalosporin acylases. There was some similarity to serine proteases, including the conservation of the active site motif, GXSYXG. Together with database searches, this suggested that the ?-amino acid ester hydrolase is a ?-lactam antibiotic acylase that belongs to a class of hydrolases that is different from the Ntn hydrolase superfamily to which the well-characterized penicillin acylase from E. coli belongs. The ?-amino acid ester hydrolase of A. turbidans represents a subclass of this new class of ?-lactam antibiotic acylases.

Polderman-Tijmes, Jolanda J.; Jekel, Peter A.; de Vries, Erik J.; van Merode, Annet E. J.; Floris, Rene; van der Laan, Jan-Metske; Sonke, Theo; Janssen, Dick B.

2002-01-01

351

Sucrose fatty acid esters suppress pancreatic secretion accompanied by peptide YY release in pancreatico-biliary diverted rats.  

PubMed

Our previous study demonstrated that intestinal administration of triglycerides suppressed protein-induced increases in pancreatic exocrine secretion in pancreatico-biliary diverted (PBD) rats, though the mechanism has not been clarified. The present study was conducted to determine whether esterified fatty acids or free fatty acids are responsible for this suppression, and whether an esterified fatty acid stimulates secretion of a pancreatic inhibitory hormone, peptide YY (PYY). We examined the effects of cocoa butter or non-digestible sucrose fatty acid esters on protein-induced pancreatic secretion in conscious PBD rats whose bile-pancreatic juice was diverted from the proximal small intestine through a catheter. Intraduodenal administration of the protein guanidinated casein hydrolysate (HGC, 150 mg in 1 ml water) enhanced pancreatic protein and trypsin secretion. However, administration of HGC with cocoa butter (100 mg ml(-1)) partly suppressed the increase in pancreatic secretion, and HGC with a highly esterified sucrose fatty acid ester, F-10 (100 mg ml(-1)), completely suppressed it. The low-esterified, water-soluble sucrose fatty acid ester F-160 also completely inhibited protein-induced pancreatic secretion in the presence or absence of the lipase inhibitor orlistat. In anaesthetized PBD rats, intraduodenal administration of HGC with sucrose ester F-160 suppressed HGC-induced pancreatic secretion, and induced PYY secretion more strongly than HGC with sucrose. These results suggest that the esterified fatty acid itself stimulates PYY release in the distal intestine, thereby inhibiting protein-induced pancreatic secretion. PMID:17384118

Hira, Tohru; Takahashi, Katsuhiko; Hara, Hiroshi

2007-07-01

352

Amonia gas: an improved reagent for chemical ionization mass spectrometry of bile acid methyl ester acetates  

SciTech Connect

The ammonia chemical ionization mass spectra of 28 methyl ester acetate derivatives of bile acids and related compounds have been determined by gas-liquid chromatography-mass spectrometry. Advantages of ammonia ionization over the previously studied isobutane ionization include a 130 to 270% enhancement in the sensitivity of base peak monitoring, and direct determination of molecular weight from the base peak (M + NH/sub 4//sup +/) in the mass spectrum of any of the derivatives. Minor ions in the ammonia spectra also allow selective detection of 3-keto compounds and can indicate unsaturation or double bond conjugation in the molecule. The significance of these studies for the detection and quantitation of bile acids is discussed. 2 tables.

DeMark, B.R.; Klein, P.D.

1981-01-01

353

N-( p-Ethynylbenzoyl) derivatives of amino acid and dipeptide methyl esters - Synthesis and structural study  

NASA Astrophysics Data System (ADS)

A series of N-( p-ethynylbenzoyl) derivatives ( 1-4) of the amino acids glycine and L-alanine as well as the dipeptides glycylglycine and L-alanylglycine has been synthesized via a two-step reaction sequence including the reaction of an appropriate N-( p-bromobenzoyl) precursor with trimethylsilylacetylene followed by deprotection of the trimethylsilyl protecting group, respectively. X-ray crystal structures of the amino acid and dipeptide methyl esters 1-4 are reported. The amide and peptide bonds within each molecular structure are planar and adopt the trans-configuration. The packing structures are governed by N sbnd H⋯O interactions leading to the formation of characteristic strand motifs. Further stabilization results from weaker C sbnd H⋯O and C sbnd H⋯? contacts.

Eimann, Frank; Weber, Edwin

2011-11-01

354

Comparison of indirect and direct quantification of glycidol fatty acid ester in edible oils.  

PubMed

Two different methods for determining the levels of glycidol fatty acid esters (GEs) in edible oil-the German official indirect method and the direct LC-MS method-are compared. In some cases, the indirect method showed lower GE levels than the direct method. This was investigated using model studies, which revealed two possible causative factors during the acid treatment of the indirect method: (1) incomplete elimination of GE in oil that was high in GEs initially and (2) generation of GEs and/or its relevant compounds in oil that was rich in partial acylglycerol. Both these factors contributed to the subsequent underestimation of GE levels. The above technical limitations of the indirect method found in the present study has led to the inference that the direct method can more precisely determine the GE levels for a wider range of fats and oil products than the indirect method. PMID:20877146

Shimizu, Masao; Kudo, Naoto; Shiro, Hiroki; Yasunaga, Koichi; Masukawa, Yoshinori; Katsuragi, Yoshihisa; Yasumasu, Takeshi

2010-01-01

355

Sorption of phthalic acid esters in two kinds of landfill leachates by the carbonaceous sorbents.  

PubMed

Sorption of phthalic acid esters (PAEs: diethyl phthalate, DEP: dibutyl phthalate, DBP as model compounds) in landfill leachates by activated carbon (AC), carbon nanotubes (CNTs), and biochars, were examined. The young leachate (YL) and old leachate (OL) were synthesized to imitate acetogenic and methanogenic phases, respectively, and glucose (GLU) and fulvic acid (FA) were selected to represent dissolved organic matter (DOM). GLU in leachates generally facilitated the sorption of PAEs while FA restrained sorption of PAEs, suggesting the type of DOM associated with leachates possibly regulated the removal efficiency of PAEs from leachates. The pores and organic carbon of carbonaceous sorbents should be major factors in influencing the sorption of PAEs in leachates. The data showed PAEs in acetogenic leachates was removed more easily than those in methanogenic leachates and CNTs have the less advantage to remove PAEs from methanogenic leachates compared to AC. PMID:23567694

Gao, Bo; Wang, Peng; Zhou, Huaidong; Zhang, Zheyun; Wu, Fengchang; Jin, Jie; Kang, Mingjie; Sun, Ke

2013-05-01

356

Molecular recognition of isomeric protonated amino acid esters monitored by ESI-mass spectrometry  

PubMed Central

Summary Two new 9,9-spirobifluorene-derived crown ethers were prepared and used to recognise constitutionally isomeric amino acid derivatives. The performance of the receptors was evaluated by ESI-mass spectrometry using the isomer labelled guest method (ILGM). This method revealed the preferred binding of L-norleucine and L-leucine compared to L-isoleucine for both receptors. Furthermore, non-covalent isotope effects demonstrate the relevance of dispersive interactions for the overall binding event. These effects also provide hints for the relative spatial orientation of the guest molecules within the hostguest complex, and thereby prove the importance of the spirobifluorene moiety for the observed binding of the protonated amino acid esters.

Liesenfeld, Andrea

2014-01-01

357

Induction of apoptosis by fatty acid ethyl esters in HepG2 cells.  

PubMed

Fatty acid ethyl esters (FAEEs) are esterification products of ethanol and fatty acids which have been found particularly in the organ damaged by ethanol abuse. To evaluate any effect of FAEEs on HepG2 cells, we added FAEEs to cell culture medium. Electrophoresis of DNA from HepG2 cells exposed to 18.5 microM ethyl palmitate (EP) and 10.6 microM ethyl stearate (ES) for 24 h revealed a smear which is typical of non-specific degradation by DNA ladder assay. Apoptosis was characterized by electron microscopy, flow cytometry revealed that the cell cycle of HepG2 cells was perturbed by exposure to FAEEs. In the present study we demonstrate that treatment of HepG2 cells with EP and ES induces apoptosis, as well as perturbing the cell cycle as the number of cells in the G(2)/M and S phases decreased. PMID:15582206

Aydin, Hikmet Hakan; Celik, Handan Ak; Deveci, Remziye; Karacali, Sabire; Saydam, Gray; Bedii Omay, Serdar; Batur, Ycel

2005-01-01

358

Perennial peanut (Arachis glabrata Benth.) leaves contain hydroxycinnamoyl-CoA:tartaric acid hydroxycinnamoyl transferase activity and accumulate hydroxycinnamoyl-tartaric acid esters.  

PubMed

Many plants accumulate hydroxycinnamoyl esters to protect against abiotic and biotic stresses. Caffeoyl esters in particular can be substrates for endogenous polyphenol oxidases (PPOs). Recently, we showed that perennial peanut (Arachis glabrata Benth.) leaves contain PPO and identified one PPO substrate, caftaric acid (trans-caffeoyl-tartaric acid). Additional compounds were believed to be cis- and trans-p-coumaroyl tartaric acid and cis- and trans-feruloyl-tartaric acid, but lack of standards prevented definitive identifications. Here we characterize enzymatic activities in peanut leaves to understand how caftaric acid and related hydroxycinnamoyl esters are made in this species. We show that peanut leaves contain a hydroxycinnamoyl-CoA:tartaric acid hydroxycinnamoyl transferase (HTT) activity capable of transferring p-coumaroyl, caffeoyl, and feruloyl moieties from CoA to tartaric acid (specific activities of 11 2.8, 8 1.8, 4 0.8 pkat mg(-1) crude protein, respectively). The HTT activity was used to make cis- and trans-p-coumaroyl- and -feruloyl-tartaric acid in vitro. These products allowed definitive identification of the corresponding cis- and trans-hydroxycinnamoyl esters extracted from leaves. We tentatively identified sinapoyl-tartaric acid as another major phenolic compound in peanut leaves that likely participates in secondary reactions with PPO-generated quinones. These results suggest hydroxycinnamoyl-tartaric acid esters are made by an acyltransferase, possibly a BAHD family member, in perennial peanut. Identification of a gene encoding HTT and further characterization of the enzyme will aid in identifying determinants of donor and acceptor substrate specificity for this important class of biosynthetic enzymes. An HTT gene could also provide a means by genetic engineering for producing caffeoyl- and other hydroxycinnamoyl-tartaric acid esters in forage crops that lack them. PMID:24556732

Sullivan, Michael L

2014-05-01

359

Profiles and levels of fatty acid esters of okadaic acid group toxins and pectenotoxins during toxin depuration. Part I: brown crab (Cancer pagurus).  

PubMed

In 2002, two outbreaks of diarrhetic shellfish poisoning (DSP) occurred in Norway, which was later confirmed to be caused by the consumption of brown crab (Cancer pagurus) contaminated predominantly by esters of okadaic acid (OA) after feeding on toxic blue mussels (Mytilus edulis). In addition to OA-group toxins, pectenotoxins (PTXs) are commonly detected in the toxin-producing algae (i.e. Dinophysis). In this paper, an experiment was set up to study the fatty acid ester profiles and depuration rates of OA-group toxins and PTXs from C. pagurus after feeding on M. edulis containing these toxin groups. OA, DTX1, DTX2 and PTX2 SA were all detected primarily in the form of fatty acid esters in the crab hepatopancreas (HP). Crabs preferentially assimilated toxins of the OA group after feeding on the mussels for 1 week. Detailed analysis of the fatty acid ester profile in crabs and mussels showed that the ester profiles in the crabs differed slightly from profiles of the fatty acid esters in M. edulis, but neither ester profile nor ester to free toxin ratio appeared to change in the crabs during the first 2 weeks of depuration. Calculations of depuration rates of the free forms of toxins resulted in similar reduction rates for OA and DTX2, whereas the depuration rate of DTX1, PTX2 and PTX2 SA was considerably faster. From the industrial perspective, the PTX-compounds are of minor importance compared to the OA group toxins in crabs, considering (1) the uncertainty regarding the oral toxicity of the PTXs, (2) the preferential ingestion of OA-group toxins compared to PTXs and (3) the faster depuration of PTXs. PMID:18619994

Torgersen, Trine; Lindegarth, Susanne; Ungfors, Anette; Sandvik, Morten

2008-09-01

360

Leaching of lead silicate glasses in acid environment: compositional and structural changes  

NASA Astrophysics Data System (ADS)

Lead silicate glasses (45.3 weight % of lead oxide) were leached in aqueous static solutions of HNO3 at pH=2 and T=90 C for different leaching times, to study the weathering mechanism of lead glasses in an acidic environment. The leached surface was analysed by different analytical techniques like RBS (Rutherford backscattering spectrometry), XPS (X-ray photoelectron spectroscopy) and SEM-EDS (scanning electron microscopy-energy dispersive spectrometry). Even the leaching solutions were analysed by ICP-AES (inductively coupled plasma-atomic emission spectroscopy) to measure the amount of lead and other ions that migrate from the glass to the solution. The results obtained show that the leached layer, depleted of lead and alkaline ions, is some hundreds of nanometres thick. It is about ten times thinner than the one obtained on richer glasses (66 weight % of lead oxide), but the kinetics of the leaching process is exactly the same: a stabilisation takes place after two days of leaching and a Pb-enriched surface thin layer (a few nanometres thick) is formed.

Bertoncello, R.; Milanese, L.; Bouquillon, A.; Dran, J.-C.; Mille, B.; Salomon, J.

361

Regioselective chlorination of 6-(5-methyl-2-oxo-4-imidazolin-4-yl)-6-oxohexanoic acid ethyl ester: A new synthesis of biotin  

Microsoft Academic Search

Regioselective chlorination of a methyl group in 6-(5-methyl-2-oxo-4-imidazolin-4-yl)-6-oxohexanoic acid ethyl ester via reaction\\u000a with sulfuryl chloride in methylene chloride has been performed for the first time. The synthesis of 5-(2-oxo-2,3-dihydro-1H-thieno[3,4-d]imidazol-4-yl)pentanoic\\u000a acid methyl and ethyl esters (tetradehydrobiotin esters) key compounds in biotin (vitamin H) synthesis has been developed\\u000a proceeding from 6-(2-oxo-5-chloromethyl-4-imidazolin-4-yl)-6-oxohexanoic acid ester.

S. I. Zavyalov; L. B. Kulikova; O. V. Dorofeeva; G. I. Ezhova; N. E. Kravchenko; A. G. Zavozin

2006-01-01

362

Highly efficient double enantioselection by lipase-catalyzed transesterification of ( R, S)-carboxylic acid vinyl esters with ( RS)-1-phenylethanol  

Microsoft Academic Search

Transesterification of the title compounds using lipase B from Candida antarctica in toluene afforded the corresponding esters in good to excellent diastereomeric excess. (R)-2-Phenylpropionic acid-(R)-1-phenethyl ester 4 was isolated in 45% yield and 64% de after 2.5 h, whereas (R)-2-phenylbutyric acid-(R)-1-phenethyl ester 5 was obtained in 40% yield and 56% de after 35 h. A single recrystallization from n-hexane gave

Hong Yang; Erik Henke; Uwe T Bornscheuer

1999-01-01

363

Silicic acid leakage from the Southern Ocean: A possible explanation for glacial atmospheric pCO2  

NASA Astrophysics Data System (ADS)

Using a simple box model, we investigate the effects of a reduced Si:N uptake ratio by Antarctic phytoplankton on the marine silica cycle and atmospheric pCO2. Recent incubation experiments demonstrate such a phenomenon in diatoms when iron is added [Hutchins and Bruland, 1998; Takeda, 1998; Franck et al., 2000]. The Southern Ocean may have supported diatoms with reduced Si:N uptake ratios compared to today during the dustier glacial times [Petit et al., 1999]. A similar reduction in the uptake ratio may be realized with an increased production of nondiatom phytoplankton such as Phaeocystis. Our model shows that reduced Si:N export ratios in the Southern Ocean create excess silicic acid, which may then be leaked out to lower latitudes. Any significant consumption of the excess silicic acid by diatoms that leads to an enhancement in their growth at the expense of coccolithophorids diminishes CaCO3 production and therefore diminishes the carbonate pump. In our box model the combination of a reduced carbonate pump and an open system carbonate compensation draw down steady state atmospheric CO2 from the interglacial 277 to 230-242 ppm, depending on where the excess silicic acid is consumed. By comparison, the atmospheric pCO2 sensitivity of general circulation models to carbonate pump forcing is ~3.5-fold greater, which, combined with carbonate compensation, can account for peak glacial atmospheric pCO2. We discuss the importance of the initial rain ratio of CaCO3 to organic carbon on atmospheric pCO2 and relevant sedimentary records that support and constrain this ``silicic acid leakage'' scenario.

Matsumoto, Katsumi; Sarmiento, Jorge L.; Brzezinski, Mark A.

2002-07-01

364

Rice Hull Ash and Silicic Acid as Adsorbents for Concentration of Bacteriocins  

PubMed Central

A model procedure has been developed for the rapid extraction of five bacteriocins (nisin, pediocin RS2, leucocin BC2, lactocin GI3, and enterocin CS1) from concentrated freeze-dried crude culture supernatants by adsorption onto acid or alkaline rice hull ash (RHA) or silicic acid (SA). Bacteriocins were adsorbed onto RHA or SA by a pH-dependent method and desorbed by decreasing the pH to 2.5 or 3.0 and heating at 90C for 5 min. The maximum adsorption and optimal pH range for different bacteriocins were as follows: nisin, 97% at pH 7.0; lactocin GI3, 94% at pH 6.0; pediocin RS2, 97% at pH 8.0 to 9.0; leucocin BC2, 88% at pH 9.0; and enterocin CS1, 94% at pH 5.0. The desorption level of lactocin GI3 or enterocin CS1 from the surfaces of both RHA and SA was 94%, while the desorption level of pediocin RS2 and leucocin BC2 was 50% or less. Nisin was desorbed readily from SA (91%) but not from RHA (50% or less). The adsorption of bacteriocins onto RHA and SA increased with the increasing concentration of bacteriocins. Analysis of the desorbed bacteriocins after dialysis and sodium dodecyl sulfate16% polyacrylamide gel electrophoresis showed a single band that gave a single inhibition zone when overlaid with Lactobacillus plantarum for detection of lactocin GI3, enterocin CS1, and nisin. RHA appears useful for extraction, concentration, and partial purification of the five bacteriocins.

Janes, M. E.; Nannapaneni, R.; Proctor, A.; Johnson, M. G.

1998-01-01

365

Lasiojasmonates A-C, three jasmonic acid esters produced by Lasiodiplodia sp., a grapevine pathogen.  

PubMed

In this study, a strain (BL 101) of a species of Lasiodiplodia, not yet formally described, which was isolated from declining grapevine plants showing wedge-shaped cankers, was investigated for its ability to produce in vitro bioactive secondary metabolites. From culture filtrates of this strain three jasmonic acid esters, named lasiojasmonates A-C and 16-O-acetylbotryosphaerilactones A and C were isolated together with (1R,2R)-jasmonic acid, its methyl ester, botryosphaerilactone A, (3S,4R,5R)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone and (3R,4S)-botryodiplodin. The structures of lasiojasmonates A-C were established by spectroscopic methods as (1R*,2R*,3'S*,4'R*,5'R*)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone, (1R*,2R*,3'S*,4'R*,5'R*,10'R*,12'R*,13'R*,14'S*) and (1R*,2R*,3'S*,4'R*,5'R*,10'S*,12'R*,13'R*,14'S*)-4-(4-hydroxymethyl-3,5-dimethyltetrahydro-furan-2-yloxymethyl)-3,5-dimethyldihydro-2-furanones jasmonates (1, 4 and 5). The structures of 16-O-acetylbotryosphaerilactones A and C were determined by comparison of their spectral data with those of the corresponding acetyl derivatives obtained by acetylation of botryosphaerilactone A. The metabolites isolated, except 4 and 5, were tested at 1mg/mL on leaves of grapevine cv. Cannonau and cork oak using the leaf puncture assay. They were also tested on detached grapevine leaves at 0.5mg/mL and tomato cuttings at 0.1mg/mL. In all phytotoxic assays only jasmonic acid was found to be active. All metabolites were inactive in the zootoxic assay at 50 ?g/mL. PMID:24768282

Andolfi, Anna; Maddau, Lucia; Cimmino, Alessio; Linaldeddu, Benedetto T; Basso, Sara; Deidda, Antonio; Serra, Salvatorica; Evidente, Antonio

2014-07-01

366

Mobilization of lead by esters of meso-2,3-dimercaptosuccinic acid  

SciTech Connect

An examination was made of the relative efficacies of 2,3-dimercapto-1-propanol (BAL) and three diesters (CH(SH)COOR)2; DMDMS, R = CH3; DEDMS, R = C2H5; and Di-PDMS, R = CH(CH3)2 of meso-2,3-dimercaptosuccinic acid (DMSA) in mobilizing freshly injected lead from mice. These diesters, like BAL, reduced the lead levels resulting from freshly injected lead in both the soft tissues (liver, kidneys, spleen, and brain) and the bone (tibia). After treatment with the dimethyl (DMDMS), the diethyl (DEDMS), and the diisopropyl (Di-PDMS) esters the lead content of each of the organs was significantly less than that present in the untreated controls. Each of the diesters reduced lead levels in the kidneys, liver, and spleen significantly below those levels found after BAL treatment. The action of the diesters in reducing brain lead levels was comparable to that of BAL. Di-PDMS was the most effective of these compounds and was significantly superior to BAL. Each of the esters was also significantly more effective than BAL in reducing the whole body level of lead.

Singh, P.K.; Jones, M.M.; Xu, Z.; Gale, G.R.; Smith, A.B.; Atkins, L.M. (Vanderbilt Univ., Nashville, TN (USA))

1989-01-01

367

Carcinogenic potential of phthalic acid esters and related compounds: structure-activity relationships.  

PubMed Central

Chronic toxicity and carcinogenicity studies of several phthalic acid esters (PAEs) and compounds containing a 2-ethylhexyl moiety were conducted in Fischer 344 rats and B6C3F1 (hybrid) mice. The compounds studied were phthalic anhydride, di(2-ethylhexyl) phthalate, butyl benzyl phthalate, diallyl phthalate, di(2-ethylhexyl) adipate, tris(2-ethylhexyl) phosphate, and 2-ethylhexyl sulfate (sodium salt). Estimated maximum tolerable doses and fractionally lower doses of each compound were administered to groups of 50 male and 50 female rats and mice for 2 years, followed by sacrifice, necropsy, and histopathological examination of major organs and tissues. The low toxic potencies of most of the compounds allowed for relatively high doses to be given during the chronic studies. In general, the toxic manifestations of the PAEs were closely correlated with their ester substituents. Although many of the PAEs possessed some carcinogenic activity, target sites for such effects were dissimilar, suggesting the absence of a common mode of action. In contrast, all of the 2-ethylhexyl-containing compounds studied possessed some hepatocarcinogenic activity, indicating that this moiety may have a propensity for causing hepatocarcinogenesis in mice, particularly those of the female sex. The 2-ethylhexyl compound that caused the greatest hepatocarcinogenic response in mice, di(2-ethylhexyl) phthalate, was also hepatocarcinogenic in rats. Similarly, those with a relatively greater effect in female mice were also active in male mice. Thus, sex and species differences in 2-ethylhexyl-induced hepatocarcinogenesis in rodents are probably quantitative rather than qualitative in nature.

Kluwe, W M

1986-01-01

368

Antinociceptive esters of N-methylanthranilic acid: Mechanism of action in heat-mediated pain.  

PubMed

Recently, we identified a new natural antinociceptive alkaloid ternanthranin, isopropyl N-methylanthranilate (ISOAN), from the plant species Choisya ternata Kunth (Rutaceae). In this work we concentrated on the elucidation of its mechanism of action in comparison with two other esters of this acid (methyl (MAN) and propyl (PAN)). Mice orally pre-treated with ISOAN, MAN or PAN (at 0.3, 1 and 3mg/kg) were less sensitive to chemical or thermal stimuli in different nociception models (formalin-, capsaicin- and glutamate-induced licking response, tail flick and hot plate). All compounds (1 and 3mg/kg) showed significant activity in the peripheral nociception models, as well as a dose-dependent spinal antinociceptive effect in the tail flick model. We observed that glibenclamide was able to reverse the antinociceptive effect of ISOAN in the hot plate model suggesting the involvement of K(+)ATP channels. The antinociceptive effect of MAN and PAN may be related to adrenergic, nitrergic and serotoninergic pathways. In addition, the antinociception of PAN was reverted by naloxone implying that the opioid pathway participates in its activity. The cholinergic and cannabinoid systems were found not be involved in the onset of the antinociceptive effects of any of the esters. In conclusion, isopropyl, methyl and propyl N-methylanthranilates produced significant peripheral and central antinociception at doses lower than that of morphine, the classical opioid analgesic drug, without causing toxicity. PMID:24486396

Pinheiro, Mariana Martins Gomes; Radulovi?, Niko S; Miltojevi?, Ana B; Boylan, Fabio; Dias Fernandes, Patrcia

2014-03-15

369

Hepatotoxicity of diisopropyl ester of malonic acid and chloromalonic acids, disinfection by-products of the fungicide isoprothiolane.  

PubMed

The fungicide isoprothiolane (diisopropyl 1,3-dithiolane-2-ylidenemalonate) decomposes to the diisopropyl esters of malonic acid (DM), chloromalonic acid (DCM) and dichloromalonic acid (DDCM) upon aqueous chlorination. In this study, the cytotoxicity of these compounds was examined using rat hepatocytes cultured on Matrigel. DCM and DDCM caused hepatocellular death at concentrations > 0.5 mM, while DM had no effect on the cell viability even at the maximum concentration examined (4 mM). Significant lipid peroxidation, measured as 2-thiobarbituric acid reactive substances, was observed in both DCM- and DDCM-treated hepatocyte cultures, and was significantly enhanced by pretreatment with 0.1 mM bis(p-nitrophenyl)phosphate (BNPP), a carboxylesterase inhibitor. When both BNPP and SKF-525A, a cytochrome P450 inhibitor, were present in the medium, DCM-induced cytotoxicity and lipid peroxidation were significantly suppressed compared to cultures with BNPP-treatment alone. By contrast, the DDCM-induced cytotoxicity was not affected by the combined pretreatment of SKF-525A and BNPP. These results indicate that DCM is metabolically activated by cytochrome P450 in an ester form, while DDCM is activated by a mechanism other than one involving cytochrome P450. To further elucidate the cytochrome P450 isozyme involved in the metabolic activation of DCM, microsomal lipid peroxidation was studied in vitro using microsomes from rats treated with beta-naphthoflavone, musk xylene, phenobarbital, pyrazole, or dexamethasone. Among these preparations, the microsomes from dexamethasone-treated rats showed the most extensive lipid peroxidation in the presence of DCM, and the lipid peroxidation was enhanced by BNPP as observed in hepatocyte cultures. These findings suggest the possible involvement of cytochrome P450 3A in the metabolic activation of DCM. PMID:9285037

Jinno, H; Hanioka, N; Nishikawa, S; Yoda, R; Toyo'oka, T; Nishimura, T; Ando, M

1997-01-01

370

The kinetics and mechanisms of the reaction of iron(III) with gallic acid, gallic acid methyl ester and catechin.  

PubMed

The kinetics and mechanisms of the reactions of a number of pyrogallol-based ligands with iron(III) have been investigated in aqueous solution at 25 degrees C and ionic strength 0.5 M NaClO(4). Mechanisms have been proposed which account satisfactorily for the kinetic data. These are generally consistent with a mechanism in which the 1:1 complex that is formed initially when the metal reacts with the ligand subsequently decays through an electron transfer reaction. There was also some evidence for the formation of a 1:2 ligand-to-metal complex at higher pH values. The kinetics of complex formation were investigated with either the ligand or metal in pseudo-first-order excess. Rate constants for k(1) of 2.83(+/-0.09)x10(3), 1.75(+/-0.045)x10(3) and 3300(+/-200) M(-1) s(-1) and k(-1) of 20(+/-6.0), 35(+/-13) and 25+/-7.6 M(-1) s(-1) have been evaluated for the reaction of Fe(OH)(2+) with gallic acid, gallic acid methyl ester and catechin, respectively. The stability constant of each [Fe(L)](+) complex has been calculated from the kinetic data. The iron(III) assisted decomposition of the initial iron(III) complex formed was investigated. Analysis of the kinetic data yielded both the equilibrium constants for protonation of the iron(III) complexes initially formed together with the rate constants for the intramolecular electron transfers for gallic acid and gallic acid methyl ester. All of the suggested mechanisms and calculated rate constants are supported by calculations carried out using global analysis of time-dependent spectra. PMID:11410233

Hynes, M J; Coinceanainn, M O

2001-06-01

371

A simple and convenient method for preparation of carboxylic acid alkyl esters, phenolic and thioesters using chlorodiphenylphosphine\\/I 2 and imidazole reagent system  

Microsoft Academic Search

Condensation of carboxylic acids with alcohols, phenols and thiols proceeded smoothly to afford carboxylic acid alkyl esters, phenolic esters and thioesters by using the combination of chlorodiphenylphosphine, imidazole and molecular iodine in refluxing acetonitrile. Esterification with this mixed reagent system gave the corresponding products in excellent yields. The phosphorus-containing byproduct was simply removed from the organic phase by basic aqueous

Najmeh Nowrouzi; Abdol Mohammad Mehranpour; Javad Ameri Rad

2010-01-01

372

Phenolic acid derivatives with potential anticancer propertiesa structureactivity relationship study. Part 1: Methyl, propyl and octyl esters of caffeic and gallic acids  

Microsoft Academic Search

The antiproliferative and cytotoxic properties of polyphenolic acid derivatives, structurally related with the natural models caffeic and gallic acids, have been tested in human cervix adenocarcinoma cells (HeLa). Simultaneous structural information was obtained for these compounds through theoretical ab initio methods. This study was conducted for the following esters: methyl caffeate (MC, 1), propyl caffeate (PC, 2), octyl caffeate (OC,

S. M. Fiuza; C. Gomes; L. J. Teixeira; M. T. Giro da Cruz; M. N. D. S. Cordeiro; N. Milhazes; F. Borges; M. P. M. Marques

2004-01-01

373

Aliphatic fatty acids and esters: Inhibition of growth and exoenzyme production of Candida, and their cytotoxicity in vitro: Anti-Candida effect and cytotoxicity of fatty acids and esters.  

PubMed

The secretion of extracellular phospholipases and proteinases of Candida has been described as a relevant virulence factor in human infections. Aliphatic fatty acids have antimicrobial properties, but the mechanism by which they affect the virulence factors of microorganisms, such as Candida, is still unclear, and there are a few reports about their toxicity. The current study investigated the in vitro antifungal activity, exoenzyme production and cytotoxicity of some aliphatic fatty acids and their ester derivatives against the Candida species. The minimum inhibitory concentration and minimum fungicidal concentrations of aliphatic medium-chain fatty acids, methyl and ethyl esters were performed using the CLSI M27-A3 method and the cytotoxicity assay was performed according to ISO 10993-5. The influence of these compounds in the inhibition of the production of hydrolytic enzymes, phospholipases and proteinases by Candida was also investigated. Data analysis was performed using the one-way ANOVA method (p?0.05). In relation to the MIC against Candida species, the fatty acid with the best result was Lauric acid, although its ester derivatives showed no activity. The inhibition of phospholipase production was more significant than the inhibition of proteinase production by Candida. Tested fatty acids revealed more than 80% cell viability in their MIC concentrations. Additionally, a cell viability of 100% was reported at concentrations of anti-enzymatic effect. Therefore, the potential use of these fatty acids could be the basis for more antimicrobial tests. PMID:24907517

Souza, Juliana L S; da Silva, Adriana F; Carvalho, Pedro H A; Pacheco, Bruna S; Pereira, Cludio M P; Lund, Rafael G

2014-09-01

374

Caffeic acid phenethyl ester attenuates IgE-induced immediate allergic reaction.  

PubMed

Caffeic acid phenethyl ester (CAPE) is the active component of honey bee propolis extracts. The results of the current study demonstrate that CAPE attenuated immunoglobulin (Ig)E-mediated allergic response in mast cells. Oral administration of CAPE inhibited IgE-mediated passive cutaneous anaphylaxis. CAPE effectively reduced both histamine and serotonin (5-HT)-induced vascular permeability in rats. CAPE also reduced histamine and leukotrienes (LTs) release from isolated rat peritoneal mast cells. Moreover, CAPE suppressed contraction induced by histamine (3 10(-8)-3 10(-5) M), 5-HT (3 10(-9)-10(-6) M) and adenosine (3 10(-8)-10(-5) M) in guinea pig tracheal zigzag. These findings provide evidence that CAPE may serve as an effective therapeutic agent for allergic diseases. PMID:22610380

Nader, Manar A

2013-04-01

375

Modification of carbon nanotube electrodes with 1-pyrenebutanoic acid, succinimidyl ester for enhanced bioelectrocatalysis.  

PubMed

Conductive materials functionalized with redox enzymes provide bioelectronic architectures with application to biological fuel cells and biosensors. Effective electron transfer between the enzyme (biocatalyst) and the conductive materials is imperative for function. Various nanostructured carbon materials are common electrode choices for these applications as both the materials' inherent conductivity and physical integrity aids optimal performance. The following chapter presents a method for the use of carbon nanotube buckypaper as a conductive architecture suitable for biocatalyst functionalization. In order to securely attach the biocatalyst to the carbon nanotube surface, the conductive buckypaper is modified with the heterobifunctional cross-linker, 1-pyrenebutanoic acid, succinimidyl ester. The technique effectively tethers the enzyme to the carbon nanotube which enhances bioelectrocatalysis, preserves the conductive nature of the carbon surface, and facilities direct electron transfer between the catalyst and material interface. The approach is demonstrated using phenol oxidase (laccase) and pyrroloquinoline quinone-dependent glucose dehydrogenase PQQ-GDH, as representative biocatalysts. PMID:23934807

Strack, Guinevere; Nichols, Robert; Atanassov, Plamen; Luckarift, Heather R; Johnson, Glenn R

2013-01-01

376

Structural Basis for the Inhibition of AKR1B10 by Caffeic Acid Phenethyl Ester (CAPE).  

PubMed

Caffeic acid phenethyl ester (CAPE), the major bioactive component of honeybee propolis, is a potent selective inhibitor of aldo-keto reductase family member?1B10 (AKR1B10), and a number of derivatives hold promise as potential anticancer agents. However, sequence homology between AKR1B10 and other members of the superfamily, including critical phase?I metabolizing enzymes, has resulted in a concern over the selectivity of any potential therapeutic agent. To elucidate the binding mode of CAPE with AKR1B10 and to provide a tool for future in silico efforts towards identifying selective inhibitors, the crystal structure of AKR1B10 in complex with CAPE was determined. The observed interactions provide an explanation for the selectivity exhibited by CAPE for AKR1B10, and could be used to guide further derivative design. PMID:24436249

Zhang, Liping; Zhang, Hong; Zheng, Xuehua; Zhao, Yining; Chen, Shangke; Chen, Yunyun; Zhang, Renwei; Li, Qing; Hu, Xiaopeng

2014-04-01

377

Theoretical, antioxidant and cytotoxic activities of caffeic acid phenethyl ester and chrysin.  

PubMed

The structure-activity relationship was used to describe the antioxidant pharmacophore of caffeic acid phenethyl ester (CAPE) and chrysin by using quantum chemical calculations and the density functional theory method. The Becke three-parameter hybrid exchange functional in combination with the Lee-Yang-Parr correction functional protocol was employed for structure optimization and other computations. Theoretical calculations were conducted to explain the structure-activity relationship and pharmacokinetic behavior of CAPE and chrysin. The free radical scavenging activities of CAPE and chrysin were evaluated by using the 2,2-diphenyl-1-picrylhydrazyl assay. The cytotoxic effects of CAPE and chrysin on the human leukemia cell line (HL-60) were evaluated by using the 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. PMID:24020631

Sulaiman, Ghassan M; Al-Amiery, Ahmed A; Bagnati, Renzo

2014-02-01

378

Synthesis of disulfide esters of dialkylaminocarbothioic acid as potent, non-detergent spermicidal agents.  

PubMed

S,S'-[disulfanediylbis(dialkylaminopropane-2,1-diyl)]bis- (dialkylaminothiocarbamate) (14-31) were prepared and evaluated for the spermicidal activity and antifungal activity. Dialkyldithiocarbamates (1-5) were reacted with epichlorohydrin to give 1-dialkylaminocarbothioic acid S-[(2,3-epithio)propyl]ester (7-11), these on further reaction with a secondary amine gave S,S'-[disulfanediylbis(dialkylaminopropane-2,1-diyl)]bis- (dialkylaminothiocarbamate) (14-31). Some of these compounds (16, 19-21, 23, 30, 31) were found to be very potent spermicidal agents with marginal antifungal activity. Two compounds (20, 21) were 25 times more active than nonoxynol-9 (N-9), the spermicide currently in the market. PMID:17765548

Dwivedi, Anil Kumar; Sharma, Vishnu Lal; Kumaria, Niharika; Kiran Kumar, S T V S; Srivastava, Pradeep Kumar; Ansari, Abdul Haq; Maikhuri, Jagdamba Prasad; Gupta, Gopal; Dhar, Janak Dulari; Roy, Raja; Joshi, Bhawani Shankar; Shukla, Praveen Kumar; Kumar, Manish; Singh, Satyawan

2007-11-01

379

High-throughput and sensitive analysis of 3-monochloropropane-1,2-diol fatty acid esters in edible oils by supercritical fluid chromatography/tandem mass spectrometry.  

PubMed

We have established a high-throughput and sensitive analytical method based on supercritical fluid chromatography (SFC) coupled with triple quadrupole mass spectrometry (QqQ MS) for 3-monochloropropane-1,2-diol (3-MCPD) fatty acid esters in edible oils. All analytes were successfully separated within 9 min without sample purification. The system was precise and sensitive, with a limit of detection less than 0.063 mg/kg. The recovery rate of 3-MCPD fatty acid esters spiked into oil samples was in the range of 62.68-115.23%. Furthermore, several edible oils were tested for analyzing 3-MCPD fatty acid ester profiles. This is the first report on the analysis of 3-MCPD fatty acid esters by SFC/QqQ MS. The developed method will be a powerful tool for investigating 3-MCPD fatty acid esters in edible oils. PMID:22749582

Hori, Katsuhito; Matsubara, Atsuki; Uchikata, Takato; Tsumura, Kazunobu; Fukusaki, Eiichiro; Bamba, Takeshi

2012-08-10

380

Yarrowia lipolytica lipase Lip2: an efficient enzyme for the production of concentrates of docosahexaenoic acid ethyl ester.  

PubMed

The production of Omega-3 (?-3) polyunsaturated fatty acids (PUFAs) rich in cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) was studied using lipase-catalysed hydrolysis of a mixture of ethyl esters from tuna oil. Lipases from Yarrowia lipolytica (YLL2), Thermomyces lanuginosus (TLL) and Candida rugosa (CRL1, CRL3 and CRL4) were tested. C. rugosa lipases discriminated esters on the basis of their chain length, with less affinity for ?-linolenate, 11-eicosenoate, arachidonate, EPA, DPA and DHA ethyl esters. However, YLL2 and TLL improved discrimination towards DHA, as enzyme selectivity was shown to be mainly based on the position of the double bond closest to the carboxylic group. From the point of view of kinetics, purity and yield, YLL2 was the most effective lipase for DHA purification. Using this enzyme in an open reactor process resulted in the highest concentrations of DHA ethyl ester (77%) and ?-3 esters (81%) with a recovery of 94% and 77% respectively. PMID:24657346

Casas-Godoy, Leticia; Meunchan, Muchalin; Cot, Marlne; Duquesne, Sophie; Bordes, Florence; Marty, Alain

2014-06-20

381

The influence of molecular structure of fatty acid monoalkyl esters on diesel combustion  

SciTech Connect

The subject of this paper is a series of experiments conducted on a single-cylinder research engine investigating the influence of molecular structure on the combustion behaviour of fatty acid alcohol ester (biodiesel) molecules under diesel engine conditions. The fuels employed in these experiments comprised various samples of pure individual fatty acid alcohol ester molecules of different structure, as well as several mixtures of such molecules. The latter consisted in biodiesel fuels produced by the transesterification of naturally occurring plant oils or animal fat with a monohydric alcohol. It was observed that the molecular structure of the fuel significantly influenced the formation of NO{sub x} and particulate matter and their respective concentration in the exhaust gas. The influence on the formation of NO{sub x} in particular, appeared to be exerted first through the effect which the molecular structure had on the auto-ignition delay occurring after the fuel was injected into the combustion chamber, and second through the flame temperature at which the various molecules burned. The emission of particulates on the other hand showed correlation with the number of double bonds in the fuel molecules for the case of larger accumulation mode particles, and with the boiling point of the fuel samples for the case of the smaller, nucleation mode particles. The effect of ignition delay on the exhaust emissions of these pollutants was isolated by adding the ignition promoting molecule 2-ethylhexyl nitrate to some of the fuel samples in closely specified concentrations, so as to equalise the ignition delay for the relevant fuel samples. The removal of the ignition delay as a main influence on the combustion process enabled the observation of the lesser effects of adiabatic flame temperature. (author)

Schoenborn, Alessandro; Ladommatos, Nicos [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Williams, John; Allan, Robert; Rogerson, John [BP Oil UK Limited, Technology Centre, Whitchurch Hill, Pangbourne, Reading, RG8 7QR (United Kingdom)

2009-07-15

382

Phase behaviour and formation of fatty acid esters nanoemulsions containing piroxicam.  

PubMed

Fatty acid esters are long-chain esters, produced from the reaction of fatty acids and alcohols. They possess potential applications in cosmetic and pharmaceutical formulations due to their excellent wetting behaviour at interfaces and a non-greasy feeling when applied on the skin surfaces. This preliminary work was carried out to construct pseudo-ternary phase diagrams for oleyl laurate, oleyl stearate and oleyl oleate with surfactants and piroxicam. Then, the preparation and optimization study via 'One-At-A-Time Approach' were carried out to determine the optimum amount of oil, surfactants and stabilizer using low-energy emulsification method. The results revealed that multi-phase region dominated the three pseudo-ternary phase diagrams. A composition was chosen from each multi-phase region for preparing the nanoemulsions systems containing piroxicam by incorporating a hydrocolloid stabilizer. The results showed that the optimum amount (w/w) of oil for oleyl laurate nanoemulsions was 30 and 20g (w/w) for oleyl stearate nanoemulsions and oleyl oleate nanoemulsions. For each nanoemulsions system, the amount of mixed surfactants and stabilizer needed for the emulsification to take place was found to be 10 and 0.5g (w/w), respectively. The emulsification process via high-energy emulsification method successfully produced nano-sized range particles. The nanoemulsions systems passed the centrifugation test and freeze-thaw cycle with no phase failures, and stable for 3months at various storage temperatures (3C, 25C and 45C). The results proved that the prepared nanoemulsions system cannot be formed spontaneously, and thus, energy input was required to produce nano-sized range particles. PMID:23386307

Mat Hadzir, Nursyamsyila; Basri, Mahiran; Abdul Rahman, Mohd Basyaruddin; Salleh, Abu Bakar; Raja Abdul Rahman, Raja Noor Zaliha; Basri, Hamidon

2013-03-01

383

A new analytical method for the quantification of glycidol fatty acid esters in edible oils.  

PubMed

A novel method to quantify glycidol fatty acid esters (GEs), supposed to present as food processing contaminants in edible oils, has been developed in combination with double solid-phase extractions (SPEs) and LC-MS measurements. The analytes were five species of synthetic GEs: glycidol palmitic, stearic, oleic, linoleic and linolenic acid esters. The use of selected ion monitoring in a positive ion mode of atmospheric chemical ionization-MS with a reversed-phase gradient LC provided a limit of quantification of 0.0045-0.012 microg/mL for the standard GEs, which enables the detection of GEs in microg ranges per gram of edible oil. Using the double SPE procedure first in reversed-phase and then in normal-phase second, allowed large amounts of co-existing acylglycerols in the oils to be removed, which improved the robustness and stability of the method in sequential runs of LC-MS measurements. When the method was used to quantify GEs in three commercial sources of edible oils, the recovery% ranged from 71.3 to 94.6% (average 79.4%) with a relative standard deviation of 2.9-12.1% for the two oils containing triacylglycerols as major components, and ranged from 90.8 to 105.1% (average 97.2%) with a relative standard deviation of 2.1-12.0% for the other, diacylglycerol-rich oil. Although the accuracy and precision of the method may not be yet sufficient, it is useful for determining trace levels of GEs and will be helpful for the quality control of edible oils. PMID:20103980

Masukawa, Yoshinori; Shiro, Hiroki; Nakamura, Shun; Kondo, Naoki; Jin, Norikazu; Suzuki, Nobuyoshi; Ooi, Naoki; Kudo, Naoto

2010-01-01

384

Modulation of fatty acid methyl esters in rats pretreated with tri-o-tolyl phosphate.  

PubMed

Formation and toxicity of fatty acid methyl esters (FAMEs) have been reported both in vitro and in vivo. In previous studies, it was shown that fatty acid ethyl ester synthase (FAEES), which catalyzes the formation of FAMEs, also expresses esterase activity. Therefore, it was hypothesized that inhibitors of esterases such as tri-o-tolyl phosphate (TOTP) can modulate the formation of FAMEs. To test this, four groups of rats were used. Group 1 served as control (vehicle only). Group 2 was treated with methanol only (3 g/kg via gavage), group 3 was given TOTP only (100 mg/kg i.p. in corn oil), and group 4 was administered TOTP as in group 3, followed by methanol after 18 h. Three hours after exposure, animals were sacrificed and FAEES activity and FAME levels were measured in blood, liver, pancreas, and brown fat. About 95% of FAEES activity was inhibited in the liver and whole blood of TOTP-treated rats (group 3) but no inhibition was observed in the pancreas or brown fat. Total hepatic FAMEs were found to be lowest for the TOTP-treated group (3) and highest in the methanol-treated animals (group 2). Total pancreatic FAMEs in different groups were not statistically different, while significant increases were observed in the brown fat in both methanol-treated groups. To verify that the oxidative metabolism of methanol was unaffected by TOTP, alcohol dehydrogenase activity was also measured and found to be unchanged in any group as compared to control. These results demonstrate that the formation of FAMEs can be modulated in the liver and probably in blood, but not in the pancreas or brown fat by the inhibitors of FAEES. PMID:15129553

Mericle, Kelly A; Kaphalia, Bhupendra S; Ansari, G A

2004-04-01

385

Effect of water on foaming properties of diglycerol fatty acid ester-oil systems.  

PubMed

We have studied the effect of added water on the nonaqueous foaming properties of diglycerol fatty acid ester nonionic surfactant systems. Diglycerol monomyristate (designated as DGM) could not foam in nonpolar oils squalane and hexadecane at normal room temperature. Nevertheless, addition of a small amount of water induces a dramatic change in foaming properties. Both the foamability and foam stability increases with the amount of added water within the studied concentration range. Phase behavior study showed that in the dilute regions there is dispersion of solid surfactant in the aforementioned oils in the DGM systems. The particle size of the dispersed solid phase was found to be several tens of microns in the water free system, and hence it tends to coagulate and precipitate. In the case of shorter alkyl chain length, diglycerol monolaurate (DGL) surfactant-oil systems, dispersion of lamellar liquid crystal (Lalpha) is observed at room temperature, and the poor foaming properties were attributed to the large particle size of the liquid crystal. In both the DGL and DGM-oil systems, we observed a tendency of the particle size to decrease with the increasing concentration of added water. At higher temperature, the solid surfactant transforms to lamellar liquid crystal phase, and foaming is improved in the DGM/squalane system. Foams are stable for several minutes. Judging from the foaming test and particle size distribution data it can be concluded that the poor foaming in the diglycerol fatty acid esters-oil systems may possibly be due to bigger particle size, which causes precipitation. Addition of water results in the dispersion of smaller particles and improves the foaming behavior. PMID:17523681

Shrestha, Lok Kumar; Shrestha, Rekha Goswami; Solans, Conxita; Aramaki, Kenji

2007-06-19

386

Influence of water solubility, side chain degradability and side chain configuration on the degradation of phthalic acid esters under methanogenic conditions.  

National Technical Information Service (NTIS)

Water solubility and degradability of side chains estrifying phthalic acid are factors possible to influence the degradation of phthalic acid esters (PAEs). To investigate the importance of these factors, degradation of butyl 2-ethylhexyl phthalate (BEHP)...

M. Alnervik

1996-01-01

387

Fast and simple method for determination of fatty acid methyl esters (FAME) in biodiesel blends using X-ray spectrometry  

Microsoft Academic Search

The determination of fatty acid methyl esters (FAME) in diesel fuel blends is an important aspect of production and blending process as well as quality control of distribution operations. In this study, energy-dispersive X-ray fluorescence spectrometer (EDXRF) is used for the first time for determination of FAME in biodiesel blends. The principle of the method is based on intensity difference

Rafal Sitko; Beata Zawisza; Zofia Kowalewska; Karina Kocot; Marzena Polowniak

2011-01-01

388

Ru-catalyzed dehydrogenative coupling of carboxylic acids and silanes - a new method for the preparation of silyl ester  

PubMed Central

Summary Ru3(CO)12/EtI has been found to be an efficient catalyst system for the dehydrosilylation of carboxylic acids with silanes. In the presence of 1 mol% Ru3(CO)12 and 4 mol% EtI, dehydrosilylation reactions in toluene afforded the corresponding silyl esters at 100 C in good and high yields.

Zhao, Hong-Yun

2008-01-01

389

Caffeic acid phenethyl ester attenuates allergic airway inflammation and hyperresponsiveness in murine model of ovalbumin-induced asthma  

Microsoft Academic Search

Caffeic acid phenethyl ester (CAPE) is a biologically active ingredient of propolis, which has several interesting biological properties, including antioxidant and anti-inflammatory; however, its anti-allergic effects are poorly understood. The objective of this study was to determine whether treatment with CAPE results in significant inhibition of asthmatic reactions in a mouse model. Mice sensitized and challenged with ovalbumin (OVA) had

Won-Kyo Jung; Da-Young Lee; Yung Hyun Choi; Sung Su Yea; Inhak Choi; Sae-Gwang Park; Su-Kil Seo; Soo-Woong Lee; Chang-Min Lee; Se-kwon Kim; You-Jin Jeon; Il-Whan Choi

2008-01-01

390

Dietary exposure of Hong Kong adults to fatty acid esters of 3-monochloropropane-1,2-diol.  

PubMed

A total of 290 individual food samples were collected in Hong Kong, China, for 3-monochloropropane-1,2-diol (3-MCPD) fatty acid esters analysis. Most samples were processed food and in ready-to-eat form. The results show that the levels of 3-MCPD fatty acid esters were high in biscuits, fats and oils, snacks and Chinese pastry with mean bound 3-MCPD levels of 440, 390, 270 and 270 ?g kg?, respectively. The dietary exposures to bound 3-MCPD of average and high adult consumers were estimated to be 0.20 and 0.53 ?g kg bw? day?, respectively. The primary toxicological concern of 3-MCPD fatty acid esters is its potential to release 3-MCPD in vivo during digestion in the gastrointestinal tract. 3-MCPD would affect the kidney, the central nervous system and the male reproductive system of rats. Assuming that 100% of the 3-MCPD was released from 3-MCPD fatty acid esters by hydrolysis in the digestive system, the dietary exposures to 3-MCPD for average and high adult consumers were only 10% and 26% of the provisional maximum tolerable daily intake (PMTDI) of 3-MCPD established by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) (2 ?g kg bw? day?), respectively. The results suggest that both average and high adult consumers are unlikely to experience major toxicological effects of 3-MCPD. PMID:23862736

Chung, H Y; Chung, Stephen W C; Chan, B T P; Ho, Yuk Yin; Xiao, Ying

2013-01-01

391

Liver and Adipose Tissue Fatty Acid Ethyl Esters Obtained at Autopsy Are Postmortem Markers for Premortem Ethanol Intake  

Microsoft Academic Search

Background: Fatty acid ethyl esters (FAEEs) are nonoxi- dative ethanol metabolites that have been implicated as mediators of alcohol-induced organ damage. FAEEs are detectable in the blood after ethanol ingestion, and on that basis have been proposed as markers of ethanol intake. Because blood is not always available at autopsy, in this study we quantified FAEEs in human liver and

Majed A. Refaai; Phan N. Nguyen; Thora S. Steffensen; Richard J. Evans; Joanne E. Cluette-Brown; Michael Laposata

2002-01-01

392

Comparison of ethyl glucuronide and fatty acid ethyl ester concentrations in hair of alcoholics, social drinkers and teetotallers  

Microsoft Academic Search

In previous investigations hair analysis for ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE) proved to be suitable for the detection of excessive alcohol consumption. The aim of this study was to compare EtG and FAEE concentrations in hair of alcoholics, social drinkers and teetotallers. Hair samples from 10 alcoholics in withdrawal treatment, 11 fatalities with documented excessive alcohol

M. Yegles; A. Labarthe; V. Auwrter; S. Hartwig; H. Vater; R. Wennig; F. Pragst

2004-01-01

393

Hydroprocessed Esters and Fatty Acids (HEFA) Bio-Based Jet Fuels: Sensory Irritation Study and Human Health Hazard Assessment.  

National Technical Information Service (NTIS)

The purpose of this technical report is two-fold. First, this technical report presents the results of a sensory irritation assay conducted in male Swiss-Webster mice exposed to different concentrations of hydroprocessed esters and fatty acids (HEFA) bio-...

B. A. Wong K. L. Mumy L. M. Sweeney R. A. James T. R. Sterner

2013-01-01

394

What Are the Sources of Exposure to Eight Frequently Used Phthalic Acid Esters in Europeans&quest  

Microsoft Academic Search

Phthalic acid esters (phthalates) are used as plasticizers in numerous consumer products, commodities, and building materials. Consequently, phthalates are found in human residential and occupational environments in high concentrations, both in air and in dust. Phthalates are also ubiquitous food and environmental contaminants. An increasing number of studies sampling human urine reveal the ubiquitous phthalate exposure of consumers in industrialized

Matthias Wormuth; Martin Scheringer; Meret Vollenweider; Konrad Hungerbhler

2006-01-01

395

Palladium-catalyzed dehydrogenative ?'-arylation of ?-keto esters under aerobic conditions: interplay of metal and Brnsted acids.  

PubMed

The Brnsted aids: The first dehydrogenative arylation of ?-keto esters with arenes under ambient aerobic conditions is described. Under a Pd(II)/Brnsted acid co-catalytic system, regioselective arylations with alkoxylated arenes and phenols were achieved in good yields, even in gram-scale conditions. PMID:22915444

Yip, Kai-Tai; Nimje, Roshan Y; Leskinen, Mikko V; Pihko, Petri M

2012-10-01

396

Synthesis of p-aminophenyl aryl H-phosphinic acids and esters via cross-coupling reactions: elaboration to phosphinic acid pseudopeptide analogues of pteroyl glutamic acid and related antifolates.  

PubMed

The synthesis of suitably protected p-aminophenyl H-phosphinic acids and esters from the corresponding para-substituted aryl halides has been accomplished via the Pd-catalyzed cross-coupling reaction of anilinium hypophosphite, either in the absence or presence of a tetraalkyl orthosilicate, to provide the free H-phosphinic acid or the corresponding ester, respectively. Subsequent conjugate addition of either a PIII species or phosphorus anion, generated in situ from either the free H-phosphinic acid or ester, to a 2-methylene glutaric acid ester provided the aryl phosphinic acid analogue of p-aminobenzoyl glutamic acid. Alkylation of these suitably protected p-aminophenyl phosphinic acid esters with a 6-(bromomethyl)pteridine or the corresponding (bromomethyl)pyridopyrmidine, followed by hydrolytic removal of protecting groups, provided the target aryl phosphinic acid analogues of folic acid and related antifolates. Alternatively, for the synthesis of the folate or 5-deazafolate analogues on a slightly larger scale, reductive amination with either N2-acetyl or N2-pivaloyl-6-formylpterin or the corresponding formylpyridopyrmidine and the same suitably protected p-aminophenyl phosphinic acid esters, followed by removal of protecting groups, is preferred. In the course of this research, it was observed that the nucleophilicity of both the aniline nitrogen and various PIII species derived from p-aminophenyl phosphinic acid derivatives is significantly reduced compared to that of the unsubstituted counterpart. PMID:17602593

Yang, Yonghong; Coward, James K

2007-07-20

397

Selective depressions of surface silicic acid within cyclonic mesoscale eddies in the oligotrophic western North Pacific  

NASA Astrophysics Data System (ADS)

To reveal spatial dynamics of silicic acid [Si(OH)4] in the poorly sampled oligotrophic western North Pacific, we investigated the surface distribution of Si(OH)4 and associated biogeochemical parameters by using an underway survey system with a highly sensitive nutrient analyzer along the 138E transect (between 30 and 34N) and the 155E transect (between 10 and 35N) during the summers of 2007 and 2008. Surface Si(OH)4 concentrations ranged from the detection limit (11 nmol L-1) to 2462 nmol L-1. High Si(OH)4 concentrations (>1000 nmol L-1) and dynamic fluctuations were generally observed north of 23N, while consistently stable low concentrations of 415-751 nmol L-1 were observed south of 23N. Surface nitrate+nitrite (N+N) and phosphate (PO43-) were typically depleted to <20 nmol L-1, except for PO43- in the area south of 16N. The majority of the study area was characterized by high-Si(OH)4 and low-N+N and PO43-. However, submesoscale/mesoscale depressions of Si(OH)4 were locally observed in the cyclonic eddy fields north of 23N. Among a total of six Si(OH)4 depressions within the eddies, a complete Si(OH)4 depletion (<11 nmol L-1) was observed on the cyclonic side near the Kuroshio axis (33.1N, 138E). This depletion was closely coupled with a diatom bloom, suggesting that Si(OH)4 was exhausted by diatoms. All of the Si(OH)4 depressions were selective and not accompanied by local depressions of N+N and PO43-. This unique phenomenon might be driven by biogeochemical processes such as selective Si export (Si pump), anomalous Si uptake associated with diatom physiology, and/or Si uptake supported by N2 fixation.

Hashihama, Fuminori; Kanda, Jota; Maeda, Yousaku; Ogawa, Hiroshi; Furuya, Ken

2014-08-01

398

Nipecotic acid ethyl ester: a cholinergic agonist that may differentiate muscarinic receptor subtypes  

SciTech Connect

Reports indicate that nipecotic acid ethyl ester (NAEE) displays cholinomimetic properties in vivo. In the present study a series of physiological and biochemical tests were conducted to characterize this action. NAEE had a negative inotropic effect on the guinea pig atrium, and stimulated contraction of the guinea pig ileum and isolated mouse stomach strip at concentrations similar to bethanechol (BCH). The atrial and ilial effects were reversed by atropine. Unlike BCH, NAEE had no effect on basal acid secretion in the isolated mouse stomach at concentrations < 100 ..mu..M. NAEE was more potent than carbachol (CCH) in displacing /sup 3/H-ONB binding from rat brain membranes. The potency of NAEE to inhibit antagonist binding in rat heart membranes was enhanced by Mg/sup + +/ (Hill coefficient < 1.0) and reduced by Gpp(NH)p. Like CCH, NAEE inhibited GTP-stimulated adenylate cyclase in rat brain striatal membranes. As compared to CCH, NAEE had little effect (< 5%) as a stimulator of inositol phosphate (IP) production in rat brain slices. The results indicate that NAEE is a direct-acting muscarinic receptor agonist. Moreover, its differential effects on acid secretion, IP accumulation, and adenylate cyclase suggest that it may be useful for defining cholinergic receptor subclasses.

Zorn, S.H.; Duman, R.S.; Enna, S.J.; Krogsgaard-Larsen, P.; Micheletti, R.; Giraldo, E.; Giachetti, A.

1986-03-05

399

Aliphatic acid esters of (2-hydroxypropyl) celluloseEffect of side chain length on properties of cholesteric liquid crystals  

Microsoft Academic Search

A series of aliphatic acid esters of (2-hydroxypropyl) cellulose (CnPC) were synthesized via the esterification of aliphatic acid chloride and (2-hydroxypropyl) cellulose (HPC). The liquid crystalline (LC) phases and transitions were investigated using differential scanning calorimetry, wide-angle X-ray diffraction (WAXD), and polarized light microscope (PLM) techniques. This series of CnPC polymers exhibited characteristic features of cholesteric LC phases between their

Bin Huang; Jason J. Ge; Yonghong Li; Haoqing Hou

2007-01-01

400

Assessing human exposure to phthalic acid and phthalate esters from mineral water stored in polyethylene terephthalate and glass bottles  

Microsoft Academic Search

Phthalic acid and phthalate esters are of growing interest due to their significant usage and potential toxicity. Polyethylene terephthalate (PET) and glass are both widely used materials for bottled drinking water. In this study, phthalic acid (PhA), bis(2-ethylhexyl) phthalate (DEHP), dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiisoBP) and dibutyl phthalate (DBP) were analysed in a large number of

P. Montuori; E. Jover; M. Morgantini; J. M. Bayona; M. Triassi

2008-01-01

401

A variant of Yarrowia lipolytica lipase with improved activity and enantioselectivity for resolution of 2-bromo-arylacetic acid esters  

Microsoft Academic Search

A variant of Lip2p lipase from Yarrowia lipolytica yeast was used for the resolution of 2-bromophenyl and o-tolyl acid esters, an important class of chemical intermediates for the pharmaceutical industry. In comparison with wild-type Lip2p, this variant, which contains one single amino acid change in the active site of the enzyme, V232A, displayed an enantioselectivity enhanced by one order of

Miguel Cancino; Philippe Bauchart; Georgina Sandoval; Jean-Marc Nicaud; Isabelle Andr; Valrie Dossat; Alain Marty

2008-01-01

402

Kinetic and stoichiometry of the reaction of chlorogenic acid and its alkyl esters against the DPPH radical.  

PubMed

The lipophilization of polar antioxidants such as phenolics is an efficient way to enhance their solubility in apolar media. Thus, in emulsified systems, lipophilized antioxidants are supposed to locate at the lipid/aqueous phase interface and to lead to a better protection of unsaturated lipids. Herein, the antiradical activity of chlorogenic acid (5-CQA) and its corresponding esters with seven fatty alcohols (from methanol to eicosanol) have been achieved using the well-known 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Hydrophobation was shown to significantly improve the antiradical activity of 5-CQA esters which reached a maximum for butyl- and octyl-chlorogenate. In addition, for both 5-CQA and its esters, it was demonstrated that the global mechanism of DPPH* stabilization proceeded likely by electron transfer (ET), while it appeared that the pathways of DPPH* stabilization were different between 5-CQA and its esters, as confirmed by the LC-MS characterization of reaction products. Finally, strong differences were found between the tested molecules allowing the proposal of different DPPH* stabilization pathways by electron transfer for 5-CQA and its esters. PMID:19143487

Lpez-Giraldo, Luis J; Laguerre, Mickal; Lecomte, Jrome; Figueroa-Espinoza, Maria-Cruz; Bara, Bruno; Weiss, Jochen; Decker, Eric A; Villeneuve, Pierre

2009-02-11

403

Synthesis of Polyfluoroalkyl Esters of (Fluorosulfonyl)difluoroacetic Acid and Diesters of Sulfonyldifluoroacetic Acid.  

National Technical Information Service (NTIS)

Previous investigations dealing with the reactions of tetrafluoroethane-beta-sultone with various nucleophilic reagents, such as amines, mercaptans, alcohols, hydrogen sulfide, and carboxylic acids gave rise to the corresponding derivatives of (fluorosulf...

T. J. Huang Z. X. Dong J. M. Shreeve

1987-01-01

404

Concurrent release of admixed antimicrobials and salicylic acid from salicylate-based poly(anhydride-esters).  

PubMed

A polymer blend consisting of antimicrobials (chlorhexidine, clindamycin, and minocycline) physically admixed at 10% by weight into a salicylic acid-based poly (anhydride-ester) (SA-based PAE) was developed as an adjunct treatment for periodontal disease. The SA-based PAE/antimicrobial blends were characterized by multiple methods, including contact angle measurements and differential scanning calorimetry. Static contact angle measurements showed no significant differences in hydrophobicity between the polymer and antimicrobial matrix surfaces. Notable decreases in the polymer glass transition temperature (T(g)) and the antimicrobials' melting points (T(m)) were observed indicating that the antimicrobials act as plasticizers within the polymer matrix. In vitro drug release of salicylic acid from the polymer matrix and for each physically admixed antimicrobial was concurrently monitored by high pressure liquid chromatography during the course of polymer degradation and erosion. Although the polymer/antimicrobial blends were immiscible, the initial 24 h of drug release correlated to the erosion profiles. The SA-based PAE/antimicrobial blends are being investigated as an improvement on current localized drug therapies used to treat periodontal disease. PMID:19180627

Johnson, Michelle L; Uhrich, Kathryn E

2009-12-01

405

Relative oral bioavailability of 3-MCPD from 3-MCPD fatty acid esters in rats.  

PubMed

In order to quantify the relative oral bioavailability of 3-chloropropane-1,2-diol (3-MCPD) from 3-MCPD fatty acid diesters in vivo, 1,2-dipalmitoyl-3-chloropropane-1,2-diol (3-MCPD diester) and 3-MCPD were orally applied to rats in equimolar doses. In both cases, the time courses of 3-MCPD concentrations were measured in blood, various organs, tissues and intestinal luminal contents. The results show that 3-MCPD is released by enzymatic hydrolysis from the 3-MCPD diester in the gastrointestinal tract and distributed to blood, organs and tissues. Based on the measurements in blood, the areas under the curve (AUC) for 3-MCPD were calculated. By comparing both AUC, the relative amount of 3-MCPD bioavailable from the 3-MCPD diester was calculated to be 86% on average of the amount bioavailable following administration of 3-MCPD. In view of limited experimental data, it is justified for the purpose of risk assessment to assume complete hydrolysis of the diesters in the gastro-intestinal tract. Therefore, assessment of the extent of exposure to 3-MCPD released from its fatty acid esters should be performed in the same way as exposure to the same molar quantity of 3-MCPD. PMID:23229518

Abraham, Klaus; Appel, Klaus E; Berger-Preiss, Edith; Apel, Elisabeth; Gerling, Susanne; Mielke, Hans; Creutzenberg, Otto; Lampen, Alfonso

2013-04-01

406

Kinetics of base hydrolysis of ?-amino acid esters catalyzed by palladium(II) piperazine complex  

Microsoft Academic Search

The kinetics of base hydrolysis of glycine, histidine, and methionine methyl esters in the presence of [Pd(pip)(H2O)2]2+ complex, where pip is piperazine, is studied in aqueous solutions, at T = 25C, and I = 0.1 mol dm?3. The rate of ester hydrolysis for glycine methyl ester is studied at different temperature and dioxane\\/water solutions of\\u000a different compositions. The kinetic data

Azza A. Shoukry; Mohamed M. Shoukry; Mohamed N. Hafez

2010-01-01

407

Oxygen absorption of methyl esters of fat acids, and the effect of antioxidants  

Microsoft Academic Search

SummaryThe oxygen absorption of methyl linolenate, methyl linoleate, methyl oleate, methyl stearate, the distilled methyl esters\\u000a of lard, and various mixtures of the four individual methyl esters were measured at 100 C. in the Barcroft-Warburg apparatus.\\u000a Mixtures of methyl esters absorbed oxygen at a rate which could be approximately predicted from the rate of oxygen absorption\\u000a of each component and

A. J. Stirton; J. Turer; R. W. Riemenschneider

1945-01-01

408

Reductions of Carboxylic Acids and Esters with NaBH4 in Diglyme at 162C  

Microsoft Academic Search

Aromatic esters, including the extremely sterically hindered ester: t-amyl 2-chlorobenzoate, are readily reduced to the corresponding benzyl alcohols in high yield with NaBH4 in refluxing diglyme (162C). In sharp contrast, aliphatic esters usually gave only low yields of alcohols. Instead, diglyme fragmentation products are formed which undergo transesterification reactions, producing complex product mixtures including products such as RCOOCH2CH2OCH3. The mechanism

Hua-Jie Zhu; Charles U. Pittman Jr

2003-01-01

409

Angiotensin converting enzyme inhibitory activity of amino acid esters of carbohydrates  

Microsoft Academic Search

l-Alanyl-d-glucose, l-valyl-d-glucose, l-phenylalanyl-d-glucose and l-phenylalanyl-lactose esters were synthesized enzymatically using two lipases viz., Rhizomucor miehei lipase (RML) and porcine pancreas lipase (PPL) and tested for their potential as inhibitors of angiotensin converting enzyme (ACE) in vitro. The esters exhibited concentration related ACE inhibitory activity. The potency of the various esters measured in terms of IC50 values were as follows: l-phenylalanyl-d-glucose,

Vasudeva Kamath; P. S. Rajini; K. Lohith; B. R. Somashekar; S. Divakar

2006-01-01

410

Fatty Acid methyl ester profiles for characterization of glomalean fungi and their endomycorrhizae.  

PubMed

Arbuscule-forming fungi in the order Glomales form obligate endomycorrhizal associations with plants that make them difficult to quantify, and taxonomy of the group is only beginning to be objectively understood. Fatty acid methyl ester (FAME) profiles were analyzed to assess the diversity and quantity of fatty acids in 53 isolates of 24 glomalean species. Spores and endomycorrhizal roots of sudan grass (Sorghum sudanense) and the citrus rootstock Carrizo citrange (Poncirus trifoliata x Citrus sinensis) were examined. Spores yielded reproducible FAME profiles from replicate spore collections extracted from soil pot cultures despite being grown in association with a host plant and with contaminating microorganisms present. Unweighted pair group analysis revealed relatively tight clusters of groups at the intraspecific, specific, and generic levels; however, lipid profiles at the family level were convergent. Thus, FAME profile comparisons provided a robust measure of similarity below the family level. FAME profiles in sudan grass roots containing vesicles and/or spores of Glomus intraradices were more similar to spore profiles than to profiles from nonmycorrhizal roots. The FAME profiles for Gigaspora species, which do not form vesicles or spores in roots, were less distinct from nonmycorrhizal roots. G. intraradices and G. rosea produced fatty acids in roots that were distinguishable from each other as well as from the host root. Production in citrus roots of the fatty acid 16:1(inf(omega)5) cis by two Glomus species was correlated with the development of mycorrhizal colonization as measured by clearing and staining procedures and by estimates of total incidence and vesicle intensity. FAME analysis of roots not only provided a measure of colonization development but also served as an index of carbon allocated to intraradical fungal growth and lipid storage. PMID:16534923

Graham, J H; Hodge, N C; Morton, J B

1995-01-01

411

Fatty Acid Methyl Ester Profiles for Characterization of Glomalean Fungi and Their Endomycorrhizae  

PubMed Central

Arbuscule-forming fungi in the order Glomales form obligate endomycorrhizal associations with plants that make them difficult to quantify, and taxonomy of the group is only beginning to be objectively understood. Fatty acid methyl ester (FAME) profiles were analyzed to assess the diversity and quantity of fatty acids in 53 isolates of 24 glomalean species. Spores and endomycorrhizal roots of sudan grass (Sorghum sudanense) and the citrus rootstock Carrizo citrange (Poncirus trifoliata x Citrus sinensis) were examined. Spores yielded reproducible FAME profiles from replicate spore collections extracted from soil pot cultures despite being grown in association with a host plant and with contaminating microorganisms present. Unweighted pair group analysis revealed relatively tight clusters of groups at the intraspecific, specific, and generic levels; however, lipid profiles at the family level were convergent. Thus, FAME profile comparisons provided a robust measure of similarity below the family level. FAME profiles in sudan grass roots containing vesicles and/or spores of Glomus intraradices were more similar to spore profiles than to profiles from nonmycorrhizal roots. The FAME profiles for Gigaspora species, which do not form vesicles or spores in roots, were less distinct from nonmycorrhizal roots. G. intraradices and G. rosea produced fatty acids in roots that were distinguishable from each other as well as from the host root. Production in citrus roots of the fatty acid 16:1(inf(omega)5) cis by two Glomus species was correlated with the development of mycorrhizal colonization as measured by clearing and staining procedures and by estimates of total incidence and vesicle intensity. FAME analysis of roots not only provided a measure of colonization development but also served as an index of carbon allocated to intraradical fungal growth and lipid storage.

Graham, J. H.; Hodge, N. C.; Morton, J. B.

1995-01-01

412

Inhibition of human term placental and fetal liver glutathione-S-transferases by fatty acids and fatty acid esters.  

PubMed

Glutathione-S-transferase (GST) activity from human term placenta and human fetal liver towards 1-chloro-2,4-dinitrobenzene as the second substrate was significantly inhibited by the saturated fatty acids, stearic (SA) and palmitic (PA) acids and fatty acid esters, ascorbyl stearate (Asc-S) and ascorbyl palmitate (Asc-P). The nature of inhibition of human placental GST was competitive towards CDNB with Ki values of 3.1, 10.0, 13.5 and 18.5 microM for Asc-S, Asc-P, PA and SA, respectively. The inhibitory effect of Asc-S on human term placental GST was reversible. I50 values for Asc-S, Asc-P, SA and PA were 15, 45, 83 and 78 microM, respectively, for partially purified human fetal liver GSTs and 21, 6, 88 and 117 microM, respectively, for partially pure rat liver GSTs. The evidence suggests that Asc-S, Asc-P, SA and PA are potent inhibitors especially of the pi-class of GST. PMID:1595087

Mitra, A; Govindwar, S; Joseph, P; Kulkarni, A

1992-05-01

413

A modified McLafferty rearrangement in the electron impact mass spectra of dansylated amino-acid methyl esters.  

PubMed

Electron impact mass spectra of dansylated amino-acids and their methyl esters show a very time intense peak at m/z 171. A systematic study failed to show the genesis and origin of this ion. The present work is devoted to the electron impact mass spectrometric (EIMS) analysis of the appearance of this ion m/z 171 in the spectra of dansylated amino-acid methyl esters and its diagnostic importance in the analysis of dansyl derivatives. A structural model for this study is offered by a series of N-alkylated aromatic sulphonamides. The EIMS spectra of these compounds indicate that the classic fragmentation is accompanied by hydrogen migration from aliphatic radicals to the aromatic ring in a manner analogous with dansylated amino-acids. A modified McLafferty rearrangement mechanism is proposed for this EI reaction. The metastable transitions and the deuterium-labelled compounds confirm this mechanism and the origin of the itinerant hydrogen. PMID:8818011

Oprean, R; Roman, L; Sandulescu, R

1996-06-01

414

Evaluation of the retention pattern on ionic liquid columns for gas chromatographic analyses of fatty acid methyl esters.  

PubMed

Fatty acid methyl esters from marine sources were analyzed by gas chromatography-mass spectrometry on three ionic liquid columns, SLB-IL61, SLB-IL82 and SLB-IL100 (Supelco). Retention indices (equivalent chain lengths) are reported for more than 100 compounds and the overlap patterns are evaluated from these data. The influence of chromatographic conditions on the retention indices of unsaturated fatty acid methyl esters is also evaluated. Compared to typical alternative phases the retention patterns on all three columns are highly dependent on the conditions. The SLB-IL61 phase had overlaps between nutritionally important fatty acids that could not be resolved by changing the chromatographic conditions. This column is therefore regarded as unsuitable for clinical and nutritional studies of the fatty acid composition, but similar overlaps may be avoided on IL82 and IL100. On all three columns double bonds close to the carboxyl group in the analytes contribute with limited retention, which makes it challenging to predict the retention of polyunsaturated fatty acid methyl esters. PMID:24873965

Lin, Chen-Chen; Wasta, Ziar; Mjs, Svein A

2014-07-11

415

Porcine liver esterase-catalyzed enantioselective hydrolysis of a prochiral diester into its optically pure (S)-ester acid, a precursor to a growth hormone secretagogue.  

PubMed

A limited screen of several commercially-available and internally-produced lipases and esterases identified porcine liver esterase as a suitable biocatalyst for the enantioselective hydrolysis of a diester into its (S)-ester acid with high optical purity (99%). This (S)-ester acid is a precursor to an experimental growth hormone secretagogue. After identifying xanthan gum as the best emulsifier and optimizing the reaction conditions, hydrolysis rates of 1 g/l.h and final (S)-ester acid (ee > 99%) titers of about 8.5 g/l were routinely achieved. This process supported the production of preparative amounts of optically pure (S)-ester (ee > 99%) with a high reaction yield of 82%. Upon purification, the (S)-ester was successfully used in the subsequent synthetic steps to yield the growth hormone secretagogue. PMID:16232487

Chartrain, M; Maligres, P; Cohen, D; Upadhyay, V; Pecore, V; Askin, D; Greasham, R

1999-01-01

416

High-chain fatty acid esters of myristyl alcohol with even carbon number: Novel organic phase change materials for thermal energy storage1  

Microsoft Academic Search

High-chain fatty acid esters have not been investigated for their thermal properties as phase change materials (PCMs) in thermal energy storage. A series of high-chain fatty acid esters of myristyl alcohol (1-tetradecanol) were synthesized via esterification of lauric, myristic, palmitic, stearic and arachidic acids under vacuum and in the absence of any catalyst. The esterification reactions were studied by FT-IR

Ahmet Alper Ayd?n; Hasancan Okutan

2011-01-01

417

Fatty Acid Ethyl Esters in Meconium: Are They Biomarkers of Fetal Alcohol Exposure and Effect?  

PubMed Central

Background Biomarkers of fetal exposure to alcohol are important to establish so that early detection and intervention can be made on these infants to prevent undesirable outcomes. The aim of this study was to analyze long-chain fatty acid ethyl esters (FAEEs) in meconium as potential biomarkers of fetal alcohol exposure and effect. Methods Fatty acid ethyl esters were analyzed in the meconium of 124 singleton infants by positive chemical ionization gas chromatography/mass spectrometry (GC/MS) and correlated to maternal ethanol use. Results A total of 124 mother/infant dyads were enrolled in the study: 31 were in the control group and 93 were in the alcohol-exposed group. The incidence (28% vs 9.7%, p=0.037) of ethyl linoleate detected in meconium was significantly higher in the alcohol-exposed groups than the control groups. Similarly, when the concentrations of ethyl linoleate in meconium were grouped (trichotomized), there was a significant linear by linear association between alcohol exposure and group concentrations of ethyl linoleate (p=0.013). Furthermore, only alcohol-exposed infants were found in the group with the highest ethyl linoleate concentration. The sensitivity of ethyl linoleate in detecting prenatal alcohol exposure was only 26.9%, and its specificity and positive predictive value were 96.8 and 96.2%, respectively. There was no significant correlation between the concentration of ethyl linoleate in meconium and absolute alcohol consumed (oz) per drinking day across pregnancy, although a trend toward a positive correlation is seen at lower amounts of alcohol consumed. Among the polyunsaturated, long-chain FAEEs, there was weak evidence that the incidence (21.5% vs 6.5%, p=0.057) and concentration (p=0.064) of ethyl arachidonate (AA) were significantly higher in the alcohol-exposed groups than the control groups. Ethyl linolenate and ethyl docosahexanoate (DHA) in meconium were found only in the alcohol group, although not at statistically significant levels. Highly significant correlations were found among the concentrations of ethyl linoleate, ethyl linolenate, ethyl AA, and ethyl DHA in meconium (correlations ranged between rs=0.203, p=0.024; and rs=0.594, p<0.001). Conclusion We conclude that FAEEs in meconium, particularly ethyl linoleate and ethyl AA, are biomarkers of high specificity for prenatal exposure to alcohol in newborn infants. We also propose that ethyl AA and DHA could be potential biomarkers of fetal alcohol effects on the developing fetal brain and should be investigated further.

Ostrea, Enrique M.; Hernandez, Joel D.; Bielawski, Dawn M.; Kan, Jack M.; Leonardo, Gregorio M.; Abela, Michelle Buda; Church, Michael W.; Hannigan, John H.; Janisse, James J.; Ager, Joel W.; Sokol, Robert J.

2011-01-01

418

Antitumor activity of caffeic acid 3,4-dihydroxyphenethyl ester and its pharmacokinetic and metabolic properties.  

PubMed

Caffeic acid 3,4-dihydroxyphenethyl ester (CADPE), a natural polyphenol from Sarcandra glabra, has potent in vitro anticancer activity through multiple targets. This study investigated its in vivo anticancer efficacy and its pharmacokinetic and metabolic characteristics. CADPE at any of the dosage regimes (ip 2.5 mg/kg at an interval of 7 h, 12 h, or 24 h for eight days) significantly decreased tumor growth in hepatoma H22 and sarcoma S180 tumor-bearing mice. CADPE also significantly inhibited H22-induced acute ascites development. The in vivo anticancer efficacies of CADPE in these tumor models were equivalent to those of 5-fluorouracil (10 mg/kg, ip) and cyclophosphamide (10 mg/kg, ip), and CADPE did not show any toxicity. A high performance liquid chromatography method with the aid of liquid chromatography/mass spectrometry was established and validated for the pharmacokinetic and metabolic studies of CADPE. CADPE was detected in blood and the organs including liver, kidney, heart, spleen, and brain 1 min after tail intravenous administration, indicating that CADPE was able to quickly distribute to these organs. CADPE was quickly hydrolyzed both in mice and in vitro mice plasma, but was much stable in vitro human plasma, suggesting a better bioavailability of CADPE in human than in mice. The major metabolites of CADPE in mice were caffeic acid, hydroxytyrosol, and a CADPE glucuronide. This was the first time to reveal the pharmacokinetic and metabolic characteristics of CADPE. Taken together, CADPE had potent in vivo antitumor activity and was able to rapidly reach the body organs and to be hydrolyzed in blood to anticancer agents of caffeic acid and hydroxytyrosol. This study suggested that CADPE has the potential for the treatment of cancers and is worthy of further study. PMID:23642645

Guo, Xin; Shen, Lu; Tong, Yuhua; Zhang, Jian; Wu, Gang; He, Qiong; Yu, Siran; Ye, Xuewei; Zou, Libo; Zhang, Zhizhen; Lian, Xiao-Yuan

2013-07-15

419

Alkyl protocatechuates as novel urinary biomarkers of exposure to p-hydroxybenzoic acid esters (parabens).  

PubMed

Human exposure to p-hydroxybenzoic acid esters (parabens) is a concern, owing to adverse health effects of these compounds. Parabens are metabolized and eliminated from the human bodies within a few hours of exposure. In this study, for the first time, methyl- and ethyl-protocatechuates (OH-MeP and OH-EtP) and their parent compounds, methyl- (MeP) and ethyl-parabens (EtP), were determined in urine samples collected from U.S. children and adults. Alkyl protocatechuates were found in almost all urine samples, with median concentrations of 11.8 (OH-MeP) and 2.90ng/mL (OH-EtP) in adults, and 5.43 (OH-MeP) and 0.85ng/mL (OH-EtP) in children. In adults, the concentrations of urinary OH-MeP and OH-EtP were higher than the corresponding concentrations of MeP and EtP. Significant correlation between OH-MeP/OH-EtP and MeP/EtP was observed. This is the first report to document hydroxylation of parabens in humans, and to propose hydroxylated metabolites (i.e., alkyl protocatechuates) as alternative biomarkers of exposure to parabens in human biomonitoring studies. The rates of transformation of parabens between children and adults appeared to be different, as evidenced from the slopes of regression between alkyl protocatechuates and parabens. In addition to alkyl protocatechuates, hydroxybenzoic acid (4-HB) and 3,4-dihydroxybenzoic acid (3,4-DHB) were found at considerable levels in the urine samples. The occurrence of a significant proportion of alkyl protocatechuates and 3,4-DHB suggests the need for inclusion of these derivatives in accurate estimation of human exposure to parabens and in epidemiological studies that associate paraben exposure to health outcomes in populations. PMID:23747757

Wang, Lei; Kannan, Kurunthachalam

2013-09-01

420

Synthesis and structural characterisation of redox-responsive N-ferrocenoyl amino acid esters; the X-ray crystal structure of N-ferrocenoyl alanine methyl ester; electrochemical anion recognition and 1H NMR complexation studies  

Microsoft Academic Search

The N-ferrocenoyl amino acid ester derivatives FcCOR {Fc=(?5-C5H5)Fe(?5-C5H4)} where R=Gly(OMe) 1, Gly(OEt) 2, Gly(OBn) 3, l-Ala(OMe) 4, l-Ala(OEt) 5, l-Leu(OMe) 6, l-Leu(OEt) 7, l-Leu(OBn) 8, l-Phe(OMe) 9 and l-Phe(OEt) 10, were prepared by coupling ferrocene carboxylic acid with the appropriate amino acid ester starting materials using the 1,3-dicyclohexylcarbodiimide (DCC), 1-hydroxybenzotriazole (HOBt) protocol and these have been characterised by spectroscopic techniques.

Michael J Sheehy; John F Gallagher; Mashita Yamashita; Yoshiteru Ida; Jennifer White-Colangelo; Jeremi Johnson; Ron Orlando; Peter T. M Kenny

2004-01-01

421

SYNTHESIS OF SOME AMINO ACID ESTER LINKED DIOXATHIAPHOSPHOCIN\\/DIOXAPHOSPHOCIN DERIVATIVES  

Microsoft Academic Search

Novel 6\\/8-amido(methoxyglycinyl\\/alaninyl)dioxathiaphosphocins\\/dioxaphosphocins (4, 7, 10) have been synthesized from reactions of monochlorides (3,6,9) with glycine methyl ester or alanine methyl ester hydrochlorides (1a,b) at room temperature in dry tetrahydrofuran in the presence of triethylamine.

L. Nagaprasada Rao; C. Devendranath Reddy; V. Krishna Reddy; K. Ananda Kumar; C. Suresh Reddy

2001-01-01

422

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester  

PubMed Central

Summary An aryl substrate with dual functionality consisting of a nitrile oxide and a pinacolyl boronate ester was prepared by mild hypervalent iodine oxidation (diacetoxyiodobenzene) of the corresponding aldoxime, without decomposition of the boronate functionality. The nitrile oxide was trapped in situ with a variety of dipolarophiles to yield aryl isoxazolines with the boronate ester function intact and available for subsequent reaction.

Harding, Sarah L; Marcuccio, Sebastian M

2012-01-01

423

In vivo and in vitro ant?neoplastic actions of caffeic acid phenethyl ester (CAPE): therapeutic perspectives.  

PubMed

Cancer prevention and treatment strategies have attracted increasing interest. Caffeic acid phenethyl ester (CAPE), an active component of propolis extract, specifically inhibits NF-?B at ?M concentrations and shows ability to stop 5-lipoxygenase-catalyzed oxygenation of linoleic acid and arachidonic acid. Previous studies have demonstrated that CAPE exhibits antioxidant, antiinflammatory, antiproliferative, cytostatic, antiviral, antibacterial, antifungal, and, most improtantly, antineoplastic properties. The primary goal of the present review is to summarize and critically evaluate the current knowledge regarding the anticancer effect of CAPE in different cancer types. PMID:23659443

Akyol, Sumeyya; Ozturk, Gulfer; Ginis, Zeynep; Armutcu, Ferah; Yigitoglu, M Ramazan; Akyol, Omer

2013-01-01

424

A database of chromatographic properties and mass spectra of fatty acid methyl esters from omega-3 products.  

PubMed

Fatty acids in products claimed to contain oils with the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were analyzed as fatty acid methyl esters by gas chromatography-mass spectrometry using electron impact ionization. To cover the variation in products on the market, the 20 products that were studied in detail were selected from a larger sample set by statistical methodology. The samples were analyzed on two different stationary phases (polyethylene glycol and cyanopropyl) and the fatty acid methyl esters were identified by methodology that combines the mass spectra and retention indices into a single score value. More that 100 fatty acids had a chromatographic area above 0.1% of the total, in at least one product. Retention indices are reported as equivalent chain lengths, and overlap patterns on the two columns are discussed. Both columns were found suitable for analysis of major and nutritionally important fatty acids, but the large number of minor compounds that may act as interferents will be problematic if low limits of quantification are required in analyses of similar sample types. A database of mass spectral libraries and equivalent chain lengths of the detected compounds has been compiled and is available online. PMID:23773584

Wasta, Ziar; Mjs, Svein A

2013-07-19

425

Stimulation of H+ Efflux and Inhibition of Photosynthesis by Esters of Carboxylic Acids 1  

PubMed Central

Suspensions of mechanically isolated Asparagus sprengeri Regel mesophyll cells were used to investigate the influence of various carboxyester compounds on rates of net H+ efflux in the dark or light and photosynthetic O2 production. Addition of 0.15 to 1.5 millimolar malathion, ?-naphthyl acetate, phenyl acetate, or p-nitrophenyl acetate stimulated H+ efflux and inhibited photosynthesis within 1 minute. In contrast, the more polar esters methyl acetoacetate or ethyl p-aminobenzoate had little or no effect on either of these two processes. A 0.15 millimolar concentration of ?-naphthylacetate stimulated the normal rate of H+ efflux, 0.77 nanomoles H+ per 106 cells per minute by 750% and inhibited photosynthesis by 100%. The four active carboxyester compounds also stimulated H+ efflux after the normal rate of H+ efflux was eliminated with 0.01 milligrams per milliliter oligomycin or 100% N2. Oligomycin reduced the ATP level by 70%. Incubation of cells with malathion, ?-naphthyl acetate, or p-nitrophenyl acetate resulted in the generation of the respective hydrolysis products ethanol, ?-naphthol, and p-nitrophenol. It is proposed that inhibition of photosynthesis and stimulation of H+ efflux result when nonpolar carboxyester compounds enter the cell and generate acidic carboxyl groups when hydrolyzed by esterase enzymes.

Duhaime, Donna E.; Bown, Alan W.

1983-01-01

426

Study of the pharmacokinetic interaction between simvastatin and prescription omega-3-acid ethyl esters.  

PubMed

The coadministration of prescription omega-3-acid ethyl esters (P-OM3) with a statin may present a treatment option for patients with mixed hyperlipidemia. This open-label, randomized, 2-way crossover, drug-drug interaction study evaluated the impact of P-OM3 capsules on plasma simvastatin pharmacokinetics in 24 healthy volunteers. Under fasted conditions, 80 mg simvastatin was administered with or without 4 g P-OM3 for two 14-day periods. After 14 days of dosing to achieve steady state, no significant differences were found in either the extent (AUC(tau)) or rate (Cmax) of exposure to simvastatin or its major beta-hydroxy metabolite after coadministration of P-OM3 with simvastatin compared with administration of simvastatin alone. At steady state, the coadministration of P-OM3 capsules did not appear to affect the pharmacokinetics of simvastatin tablets. The combination of P-OM3 capsules and simvastatin appeared to be well tolerated. PMID:16809804

McKenney, J M; Swearingen, D; Di Spirito, M; Doyle, R; Pantaleon, C; Kling, D; Shalwitz, R A

2006-07-01

427

Direct GC-(EI)MS determination of fatty acid alkyl esters in olive oils.  

PubMed

A new analytical method for fatty acid alkyl esters (FAAEs) determination by GC-MS in virgin olive oils is proposed. No sample preparation is required and FAAEs are directly thermo-desorbed and cryo-focalised in the cooled injector of a GC-MS (EI) instrument. The analytical conditions were optimized by Design of Experiment (DoE) techniques (an exploratory Plackett-Burman design followed by a factorial design on three selected variables). After the improvement of method performances, several samples of extra virgin and low quality virgin olive oils were analyzed both by the new method and by the Official EU Method of analysis. The application of Principal Component Analysis to the obtained results confirmed that the ability of the proposed method to discriminate between extra virgin and lower quality olive oils is at least equal to that of the Official Method, but the new method is faster, simpler, requires a much lower amount of organic solvents and significantly enhances method repeatability. PMID:24401385

Boggia, Raffaella; Borgogni, Cristina; Hysenaj, Vilma; Leardi, Riccardo; Zunin, Paola

2014-02-15

428

Determination of alkylphenols after derivatization to ferrocenecarboxylic acid esters with gas chromatography-atomic emission detection.  

PubMed

A method is described for the rapid determination of alkylphenols in nonpolar matrixes. The alkylphenols are derivatized with ferrocenecarboxylic acid chloride so that every phenol molecule is labeled with one iron atom. The resulting esters are analyzed by gas chromatography with atomic emission detection (AED) in the iron-selective detection mode. This method utilizes the AED's low detection limit (0.05 pg/s) for iron and the high selectivity versus carbon (3.5 x 10(6)) for the detection of the alkylphenols. Because the derivatization is performed before the first step of sample preparation, the risk of analyte loss by adsorption or volatilization is minimized. The total recoveries in the lower ppm concentration range vary between 79 and 125%. The quantification of 20 C0-C3-alkylphenols in crude oils is demonstrated by analyzing a shale oil (SRM 1580) and a petroleum crude oil (SRM 1582). The complete workup is easily carried out in only 45 min/sample. PMID:11467556

Rolfes, J; Andersson, J T

2001-07-01

429

S-(-)-10,11-dihydroxyfarnesoic Acid methyl ester inhibits melanin synthesis in murine melanocyte cells.  

PubMed

The development of antimelanogenic agents is important for the prevention of serious aesthetic problems such as melasmas, freckles, age spots, and chloasmas. In the course of screening for melanin synthesis inhibitors, we found that the culture broth from an insect morphopathogenic fungus, Beauveria bassiana CS1029, exhibits potent antimelanogenic activity. We isolated and purified an active metabolite and identified it as S-(-)-10,11-dihydroxyfarnesoic acid methyl ester (dhFAME), an insect juvenile hormone. To address whether dhFAME inhibits melanin synthesis, we first measured the size of the melanin biosynthesis inhibition zone caused by dhFAME. dhFAME also showed inhibitory activity against mushroom tyrosinase in Melan-a cells. Intracellular, dose-dependent tyrosinase inhibition activity was also confirmed by zymography. In addition, we showed that dhFAME strongly inhibits melanin synthesis in Melan-a cells. Furthermore, we compared levels of TYR, TRP-1, TRP-2, MITF, and MC1R mRNA expression by reverse-transcription polymerase chain reaction and showed that treatment of Melan-a cells with 35 ?M dhFAME led to an 11-fold decrease in TYR expression, a 6-fold decrease in TRP-2 expression, and a 5-fold decrease in MITF expression. Together, these results indicate that dhFAME is a potent inhibitor of melanin synthesis that can potentially be used for cosmetic biomaterial(s). PMID:25046747

Baek, Seung-Hwa; Ahn, Jun-Won; Nam, Sung-Hee; Yoon, Cheol-Sik; Shin, Jae-Cheon; Lee, Sang-Han

2014-01-01

430

Production of Fatty Acid Butyl Esters Using the Low Cost Naturally Immobilized Carica papaya Lipase.  

PubMed

In this work, the low cost naturally immobilized Carica papaya lipase (CPL) was investigated for production of fatty acid butyl esters (FABE) to fulfill the aim of reducing the lipase cost in the enzymatic butyl-biodiesel process. The CPL showed specificities to different alcohol acyl acceptors. Alcohols with more than three carbon atoms did not have negative effects on the CPL activity. The CPL catalyzed butanolysis for FABE production was systematically investigated. The reaction solvent, alcohol/oil molar ratio, enzyme amount, reaction temperature, and water activity all affected the butanolysis process. Under the optimized conditions, the highest conversion of 96% could be attained in 24 h. These optimal conditions were further applied to CPL catalyzed butanolysis of other vegetable oils. All of them showed very high conversion. The CPL packed-bed reactor was further developed, and could be operated continuously for more than 150 h. All of these results showed that the low cost Carica papaya lipase can be used as a promising lipase for biodiesel production. PMID:24954104

Su, Erzheng; Wei, Dongzhi

2014-07-01

431

Sono-alkalization pretreatment of sewage sludge containing phthalate acid esters.  

PubMed

This work experimentally elucidates the efficiencies of sono-alkalization treatment on municipal sewage sludge. The total solids (TS) concentration of the sewage sludge was pre-adjusted at 29.7 g/L. Two parameters such as sodium hydroxide (NaOH) dosage and sonication time were considered by the central composite design (CCD) program to investigate the effect on the degradation of phthalate acid esters (PAEs) and solubilization of soluble chemical oxygen demand (SCOD). The mean concentrations of dibutyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP) and butyl benzyl phthalate (BBP) in the sewage sludge were 718, 41 and 8 mg/kg dry weight sludge, respectively. Sono-alkalization process was effective on the degradation of DBP but worthless for DEHP and BBP. Overall degradation of DBP in sewage sludge was estimated to be 100% at the NaOH dosage of 68 m Mand sonication time of 2.2 min. Sono-alkalization was responsible for 6,000 mg/L increase of SCOD based on the decrease of volatile solids in sewage sludge. PMID:21847788

Ma, Ying-Shih; Lin, Jih-Gaw

2011-01-01

432

Caffeic acid phenethyl ester protects against tamoxifen-induced hepatotoxicity in rats.  

PubMed

Tamoxifen (TAM) is widely used in the treatment and prevention of breast cancer. Adverse effects of TAM include hepatotoxicity. Caffeic acid phenethyl ester (CAPE), an active component of propolis, has been used in folk medicine for diverse ailments. In the current study, the protective effects of CAPE against TAM-induced hepatotoxicity in female rats were evaluated. TAM (45 mg/kg/day, i.p., for 10 consecutive days) resulted in an elevation of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), depletion of liver reduced glutathione (GSH) and accumulation of oxidized glutathione (GSSG) and lipid peroxidation (LPO). Also, TAM treatment resulted in inhibition of hepatic activity of glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT). Further, it raised liver tumor necrosis factor-alpha (TNF-alpha) level and induced histopathological changes. Pretreatment with CAPE (2.84 mg/kg/day; i.p., for 20 consecutive days, starting 10 days before TAM injection) significantly prevented the elevation in serum activity of the assessed enzymes. CAPE significantly inhibited TAM-induced hepatic GSH depletion and GSSG and LPO accumulation. Consistently, CAPE normalized the activity of GR, GPx, SOD and CAT, inhibited the rise in TNF-alpha and ameliorated the histopathological changes. In conclusion, CAPE protects against TAM-induced hepatotoxicity. PMID:19394397

Albukhari, Ashwag A; Gashlan, Hana M; El-Beshbishy, Hesham A; Nagy, Ayman A; Abdel-Naim, Ashraf B

2009-07-01

433

Caffeic Acid Phenethyl Ester Inhibits Epithelial-Mesenchymal Transition of Human Pancreatic Cancer Cells  

PubMed Central

Background. This study aimed to investigate the effect of propolis component caffeic acid phenethyl ester (CAPE) on epithelial-mesenchymal transition (EMT) of human pancreatic cancer cells and the molecular mechanisms underlying these effects. Methods. The transforming growth factor ? (TGF-?-) induced EMT in human pancreatic PANC-1 cancer cells was characterized by observation of morphology and the expression of E-cadherin and vimentin by western blotting. The migration potential was estimated with wound closure assay. The expression of transcriptional factors was measured by quantitative RT-PCR and immunocytochemistry staining. The orthotopic pancreatic cancer xenograft model was used for in vivo assessment. Results. The overexpression of vimentin was attenuated by CAPE, and the alteration in morphology from polygonal to spindle shape was partially reversed by CAPE. Furthermore, CAPE delayed the TGF-?-stimulated migration potential. CAPE treatment did not reduce the expression levels of Smad 2/3, Snail 1, and Zeb 1 but inhibited the expression of transcriptional factor Twist 2. By using an orthotopic pancreatic cancer model, CAPE suppressed the expression of Twist 2 and growth of PANC-1 xenografts without significant toxicity. Conclusion. CAPE could inhibit the orthotopic growth and EMT of pancreatic cancer PANC-1 cells accompanied by downregulation of vimentin and Twist 2 expression.

Chen, Ming-Jen; Shih, Shou-Chuan; Wang, Horng-Yuan; Lin, Ching-Chung; Liu, Chia-Yuan; Wang, Tsang-En; Chu, Cheng-Hsin; Chen, Yu-Jen

2013-01-01

434

Caffeic acid phenethyl ester as an adjuvant therapy for advanced prostate cancer.  

PubMed

Prostate cancer is the second most frequently diagnosed cancer of men. Androgen ablation therapy is the primary treatment for metastatic prostate cancer. However, the majority of prostate cancer patients receiving the androgen ablation therapy will ultimately develop recurrent castration-resistant tumors within 3 years. Chemotherapy shows little effect on prolonging survival for patients with metastatic hormone-refractory prostate cancer. More than 80% of prostate tumors acquire mutation or deletion of tumor suppressor phosphatase and tensin homolog (PTEN), a negative regulator of PI3K/Akt signaling. Caffeic acid phenethyl ester (CAPE) is a strong antioxidant extracted from honeybee hive propolis. Recent studies indicate that CAPE treatment suppresses tumor growth and Akt signaling in human prostate cancer cells. Combined treatments of CAPE with chemotherapeutic drugs exhibit synergistic suppression effects. Pharmacokinetic studies suggest that intraperitoneal injection of CAPE at concentration of 10mg/kg is not toxic. CAPE treatment sensitizes cancer cells to chemotherapy and radiation treatments. In addition, CAPE treatment protects therapy-associated toxicities in animal models. We therefore propose that administration of CAPE is a potential adjuvant therapy for patients with castration-resistant prostate cancer. PMID:23462369

Liu, Chun-Chieh; Hsu, Jong-Ming; Kuo, Li-Kuo; Chuu, Chih-Pin

2013-05-01

435

Caffeic Acid phenethyl ester inhibits epithelial-mesenchymal transition of human pancreatic cancer cells.  

PubMed

Background. This study aimed to investigate the effect of propolis component caffeic acid phenethyl ester (CAPE) on epithelial-mesenchymal transition (EMT) of human pancreatic cancer cells and the molecular mechanisms underlying these effects. Methods. The transforming growth factor ? (TGF-?-) induced EMT in human pancreatic PANC-1 cancer cells was characterized by observation of morphology and the expression of E-cadherin and vimentin by western blotting. The migration potential was estimated with wound closure assay. The expression of transcriptional factors was measured by quantitative RT-PCR and immunocytochemistry staining. The orthotopic pancreatic cancer xenograft model was used for in vivo assessment. Results. The overexpression of vimentin was attenuated by CAPE, and the alteration in morphology from polygonal to spindle shape was partially reversed by CAPE. Furthermore, CAPE delayed the TGF-?-stimulated migration potential. CAPE treatment did not reduce the expression levels of Smad 2/3, Snail 1, and Zeb 1 but inhibited the expression of transcriptional factor Twist 2. By using an orthotopic pancreatic cancer model, CAPE suppressed the expression of Twist 2 and growth of PANC-1 xenografts without significant toxicity. Conclusion. CAPE could inhibit the orthotopic growth and EMT of pancreatic cancer PANC-1 cells accompanied by downregulation of vimentin and Twist 2 expression. PMID:23662124

Chen, Ming-Jen; Shih, Shou-Chuan; Wang, Horng-Yuan; Lin, Ching-Chung; Liu, Chia-Yuan; Wang, Tsang-En; Chu, Cheng-Hsin; Chen, Yu-Jen

2013-01-01

436

Caffeic Acid phenethyl ester as a potential treatment for advanced prostate cancer targeting akt signaling.  

PubMed

Prostate cancer is the fifth most common cancer overall in the world. Androgen ablation therapy is the primary treatment for metastatic prostate cancer. However, most prostate cancer patients receiving the androgen ablation therapy ultimately develop recurrent castration-resistant tumors within 1-3 years after treatment. The median overall survival time is 1-2 years after tumor relapse. Chemotherapy shows little effect on prolonging survival for patients with metastatic hormone-refractory prostate cancer. More than 80% of prostate tumors acquire mutation or deletion of tumor suppressor phosphatase and tensin homolog (PTEN), a negative regulator of PI3K/Akt signaling, indicating that inhibition of PI3K/Akt might be a potential therapy for advanced prostate tumors. Caffeic acid phenethyl ester (CAPE) is a strong antioxidant extracted from honeybee hive propolis. CAPE is a well-known NF-?B inhibitor. CAPE has been used in folk medicine as a potent anti-inflammatory agent. Recent studies indicate that CAPE treatment suppresses tumor growth and Akt signaling in human prostate cancer cells. We discuss the potential of using CAPE as a treatment for patients with advanced prostate cancer targeting Akt signaling pathway in this review article. PMID:23466879

Lin, Hui-Ping; Lin, Ching-Yu; Liu, Chun-Chieh; Su, Liang-Cheng; Huo, Chieh; Kuo, Ying-Yu; Tseng, Jen-Chih; Hsu, Jong-Ming; Chen, Chi-Kuan; Chuu, Chih-Pin

2013-01-01

437

High biobased content epoxy-anhydride thermosets from epoxidized sucrose esters of Fatty acids.  

PubMed

Novel highly functional biobased epoxy compounds, epoxidized sucrose esters of fatty acids (ESEFAs), were cross-linked with a liquid cycloaliphatic anhydride to prepare polyester thermosets. The degree of cure or conversion was studied using differential scanning calorimetry (DSC), and the sol content of the thermosets was determined using solvent extraction. The mechanical properties were studied using tensile testing to determine Young's modulus, tensile stress, and elongation at break. Dynamic mechanical analysis (DMA) was used to determine glass-transition temperature, storage modulus, and cross-link density. The nanomechanical properties of the surfaces were studied using nanoindentation to determine reduced modulus and indentation hardness. The properties of coatings on steel substrates were studied to determine coating hardness, adhesion, solvent resistance, and mechanical durability. Compared with the control, epoxidized soybean oil, the anhydride-cured ESEFAs have high modulus and are hard and ductile, high-performance thermoset materials while maintaining a high biobased content (71-77% in theory). The exceptional performance of the ESEFAs is attributed to the unique structure of these macromolecules: well-defined compact structures with high epoxide functionality. These biobased thermosets have potential uses in applications such as composites, adhesives, and coatings. PMID:21561167

Pan, Xiao; Sengupta, Partha; Webster, Dean C

2011-06-13

438

Utilization of rapeseed pellet from fatty acid methyl esters production as an energy source.  

PubMed

Rapeseed pellet - crushed seed residue from oil extraction is a by-product of fatty acid methyl esters production process. As other types of biomass, it can either be burned directly in furnaces or processed to increase its energetic value. Biomass is renewable, abundant and has domestic usage; the sources ofbiomass can help the world reduce its dependence on petroleum products, fossil coal and natural gas. Energetically effective utilization of rapeseed pellet could substantially improve the economic balance of an individual household in which biodiesel for fulfilling the producer's own energetic demand is obtained. In this article, the experimental results of combusting rapeseed pellet in a calorimeter, combustion in a boiler heater and the analysis of the emissions level of different pollutants in exhaust fumes during different stages of biomass boiler operation are presented. It has been proved that the pellet, a by-product of biodiesel production, is not only a valuable substitute of animal fodder, but also an excellent renewable and environmentally friendly energy source, viable for use in household tap water heating installations. PMID:24600857

Ciunel, Krzysztof; Klugmann-Radziemska, Ewa

2014-01-01

439

Caffeic acid phenethyl ester (CAPE), an active component of propolis, inhibits Helicobacter pylori peptide deformylase activity.  

PubMed

Helicobacter pylori (H. pylori) is a major causative factor for gastrointestinal illnesses, H. pylori peptide deformylase (HpPDF) catalyzes the removal of formyl group from the N-terminus of nascent polypeptide chains, which is essential for H. pylori survival and is considered as a promising drug target for anti-H. pylori therapy. Propolis, a natural antibiotic from honeybees, is reported to have an inhibitory effect on the growth of H. pylori in vitro. In addition, previous studies suggest that the main active constituents in the propolis are phenolic compounds. Therefore, we evaluated a collection of phenolic compounds derived from propolis for enzyme inhibition against HpPDF. Our study results show that Caffeic acid phenethyl ester (CAPE), one of the main medicinal components of propolis, is a competitive inhibitor against HpPDF, with an IC50 value of 4.02 ?M. Furthermore, absorption spectra and crystal structural characterization revealed that different from most well known PDF inhibitors, CAPE block the substrate entrance, preventing substrate from approaching the active site, but CAPE does not have chelate interaction with HpPDF and does not disrupt the metal-dependent catalysis. Our study provides valuable information for understanding the potential anti-H. pylori mechanism of propolis, and CAPE could be served as a lead compound for further anti-H. pylori drug discovery. PMID:23611786

Cui, Kunqiang; Lu, Weiqiang; Zhu, Lili; Shen, Xu; Huang, Jin

2013-05-31

440

Beneficial effects of caffeic acid phenethyl ester in a rat model of vascular injury  

PubMed Central

The aim of this study was to evaluate whether caffeic acid phenethyl ester (CAPE), an active component of propolis, was able to reduce neointimal formation in a model of endothelial injury of rat carotid artery (balloon angioplasty). Furthermore, we investigated the relationship between neointima formation and nuclear factor-?B (NF-?B) activation and we correlated NF-?B activation to the expression of inducible isoform of cyclo-oxygenase (COX-2) in injured carotids.In control group a significant proliferation of neointima was observed 14 days after balloon angioplasty, which was correlated to an increase of NF-?B/DNA binding activity as well as p50/p65 nuclear levels compared to those observed in the carotids from sham-operated rats. Furthermore, NF-?B activation was correlated to increased COX-2, but not ?-actin, protein expression.Treatment of rats for 14 days with CAPE (3, 10, 30?mg?kg?1) caused a significant inhibition of all the parameters assayed, except ?-actin protein expression.These results indicate that treatment with CAPE may lead to a reduction of neointima formation by inhibiting NF-?B activation and suggest that this agent may have therapeutic relevance for the prevention of human restenosis.

Maffia, Pasquale; Ianaro, Angela; Pisano, Barbara; Borrelli, Francesca; Capasso, Francesco; Pinto, Aldo; Ialenti, Armando

2002-01-01