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1

Adsorption kinetics of silicic acid on akaganeite.  

PubMed

As part of a series of studies on the interaction between ferric ions and silicic acid in the hydrosphere, the adsorption of silicic acid on akaganeite was investigated kinetically at various pH values. The adsorption of silicic acid increased with increasing pH over an initial pH range of 4-11.5. In the kinetic experiment, the Cl(-) was released from akaganeite much faster than silicic acid was adsorbed. From this result, we concluded that chloride ions bound on the surface of akaganeite are released and Fe-OH or Fe-O(-) sites are formed, which then acts as an adsorption site for silicic acid. The uptake mechanism of silicic acid by akaganeite is significantly different from that by schwertmannite, despite the presence of the same tunnel structure. PMID:23538050

Naren, Gaowa; Ohashi, Hironori; Okaue, Yoshihiro; Yokoyama, Takushi

2013-06-01

2

Fumaric acid esters in dermatology.  

PubMed

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. PMID:23130241

Wollina, Uwe

2011-07-01

3

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

4

40 CFR 721.10323 - Glycerol fatty acid ester (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Glycerol fatty acid ester (generic). 721...Chemical Substances § 721.10323 Glycerol fatty acid ester (generic). ...chemical substance identified generically as glycerol fatty acid ester (PMN...

2012-07-01

5

40 CFR 721.10323 - Glycerol fatty acid ester (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Glycerol fatty acid ester (generic). 721...Chemical Substances § 721.10323 Glycerol fatty acid ester (generic). ...chemical substance identified generically as glycerol fatty acid ester (PMN...

2013-07-01

6

Quantitative separations of higher fatty acid methyl esters by adsorption chromatography on silica impregnated with silver nitrate  

Microsoft Academic Search

A chromatographic adsorbent has been developed for the separation of geometric isomers of fatty acid methyl esters. The adsorbent\\u000a consists of silicic acid impregnated with silver nitrate.\\u000a \\u000a Quantitative separations of saturated,cis-, andtrans-monoenoic and polyenoic methyl esters in 30 to 100 mg quantities are reported.

B. De Vries

1963-01-01

7

Carboxylic Acid Esters as Substrates of Cholinesterases  

NASA Astrophysics Data System (ADS)

Data on the kinetics of the hydrolysis of various carboxylic acid esters by two main types of cholinesterases — acetylcholinesterase from human erythrocytes and butyrylcholinesterase from horse blood serum — are surveyed. It is shown that the rate of enzyme hydrolysis depends significantly on the structure of the acyl part of the ester molecule, the nature of the ester heteroatom, the structure of the alcohol component, and particularly the structure of the onium group. Esters based on natural products are of special interest as specific substrates of these enzymes. The role of the productive and non-productive sorption of the substrates in enzyme catalysis is demonstrated. The bibliography includes 81 references.

Brestkin, A. P.; Rozengart, E. V.; Abduvakhabov, A. A.; Sadykov, A. A.

1983-10-01

8

Synthesis of optically active phosphonamino acids esters at microwave assistance  

Microsoft Academic Search

A preparative synthesis was developed for phosphonamino acids esters proceeding from natural amino acids with the use of microwave\\u000a assistance. A series of phosphonamino acids esters was prepared from optically active natural ?-amino acids.

M. M. Kabachnik; E. V. Villemson; I. P. Beletskaya

2008-01-01

9

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

10

Performance of sulfoxylated fatty acid methyl esters  

Microsoft Academic Search

Sulfoxidation of fatty acid methyl esters with SO2, O2, and ultraviolet light of appropriate wavelength has led to the synthesis of methyl esters sulfonates or sulfoxylates known\\u000a as ?-MES because of the possible random position of SO3 group in the alkyl chain. This work describes experimental measurements of physical properties such as solubility and viscosity\\u000a of sodium ?-MES water solutions.

Leon Cohen; Francisco Trujillo

1999-01-01

11

21 CFR 172.854 - Polyglycerol esters of fatty acids.  

...Polyglycerol esters of fatty acids. Polyglycerol esters of fatty acids, up to and including the...cottonseed oil, lard, palm oil from fruit, peanut oil, safflower oil...oil, and tallow and the fatty acids derived from these...

2014-04-01

12

Flammability Studies of Polymer Layered Silicate Nanocomposites: Polyolefin, Epoxy and Vinyl Ester Resins  

NSDL National Science Digital Library

In the pursuit of improved approaches to fire retarding polymers a wide variety of concerns must be addressed, in addition to the flammability issues. For commodity polymers the low cost of these materials requires that the fire retardant (FR) approach also be of low cost. This limits solutions to the problem primarily to additive type approaches. These additives must be low cost and easily processed with the polymer. In addition, any additive must not excessively degrade the other performance properties of the polymer, and it must not create environmental problems in terms of recycling or disposal of the final product. Polymer layered silicate (PLS) nanocomposites are materials that may fulfil the above requirements for a high performance flame retardant. PLS nanocomposites are hybrid organic polymer-inorganic materials with unique properties when compared with conventional filled polymers [1]. For example, the mechanical properties of a nylon-6 layered-silicate nanocomposite, with a silicate mass fraction of only 5%, show excellent improvement over those for the pure nylon 6. The nanocomposite exhibits a 40% higher tensile strength, 68% greater tensile modulus, 60% higher flexural strength, and a 126% increased flexural modulus. The heat distortion temperature (HDT) is increased from 65 °C to 152 °C [2]. In some cases, increased thermal stability, an important property for improving flammability performance, as well as decreased gas permeability, and increased solvent resistance accompany the improved physical properties. We have reported on the flammability properties of delaminated nylon 6 layered silicate nanocomposites and intercalated polymer layered-silicate nanocomposites prepared from polystyrene (PS) and polypropylene-graft-maleic anhydride (PP-g-MA) [3, 4]. Here, we will briefly review these results and report on our initial studies of the flammability of thermoset PLS nanocomposites: intercalated vinyl ester silicate and intercalated epoxy silicate nanocomposites.

Gilman, J. W.; Kashiwagi, T.; Nyden, M. R.; Brown, J. E.; Jackson, C. L.; Lomakin, S.

1999-01-01

13

75 FR 71556 - Polyoxyalkylated Glycerol Fatty Acid Esters; Tolerance Exemption  

Federal Register 2010, 2011, 2012, 2013

...EPA-HQ-OPP-2009-0061; FRL-8852-2] Polyoxyalkylated Glycerol Fatty Acid Esters; Tolerance Exemption...tolerance for residues of polyoxyalkylated glycerol fatty acid esters; the mono-, di...oxide, also known as polyoxyalkylated glycerol fatty acid esters, when used as...

2010-11-24

14

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

Code of Federal Regulations, 2011 CFR

...condensate, phosphoric acid ester salts. 721.6200 Section 721...condensate, phosphoric acid ester salts. (a) Chemical substances...condensate, phosphate ester salts (PMNs P-90-1984 and...uses are: (i) Release to water. Requirements as...

2011-07-01

15

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

Code of Federal Regulations, 2013 CFR

...condensate, phosphoric acid ester salts. 721.6200 Section 721...condensate, phosphoric acid ester salts. (a) Chemical substances...condensate, phosphate ester salts (PMNs P-90-1984 and...uses are: (i) Release to water. Requirements as...

2013-07-01

16

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

Code of Federal Regulations, 2012 CFR

...condensate, phosphoric acid ester salts. 721.6200 Section 721...condensate, phosphoric acid ester salts. (a) Chemical substances...condensate, phosphate ester salts (PMNs P-90-1984 and...uses are: (i) Release to water. Requirements as...

2012-07-01

17

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. PMID:24971312

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

2014-01-01

18

Different mechanisms of silicic acid leakage from the Southern Ocean  

NASA Astrophysics Data System (ADS)

Ten years ago, the silicic acid leakage hypothesis (SALH) was proposed to help explain the glacial-interglacial variation in atmospheric CO2. It called on an enhanced delivery of aeolian iron to the glacial Southern Ocean in order to reduce Antarctic diatoms' requirement for silicic acid. SALH proposed that the reduction created a pool of excess silicic acid in the surface Southern Ocean that was subsequently "leaked" to the world ocean by intermediate waters. It further proposed that the leakage fueled changes in the floral composition and drove CO2 down. Here, using an Earth system model of intermediate complexity, we explore two alternative mechanisms of silicic acid leakage: sea ice expansion and changes in southern hemisphere westerlies. We show that, as with iron, these triggers too can cause a silicic acid leakage but with different distributions of production and biogeochemical tracers. The new model results are evaluated in the context of available data.

Matsumoto, K.; Chase, Z.; Kohfeld, K. E.

2012-12-01

19

Poly(carbonate ester)s Based on Units of 6-Hydroxyhexanoic Acid and Glycerol  

E-print Network

Poly(carbonate ester)s Based on Units of 6-Hydroxyhexanoic Acid and Glycerol Jesse B. Wolinsky(trimethylene carbon- ate), and most notably poly(glycolic acid) and poly(lactic acid), have met wide acceptance- and nanoparticles for drug delivery applications.5-8 When a polymer does not meet the requirements for an intended

20

Superacidic cyclization of higher terpenoid acids and their esters  

Microsoft Academic Search

The superacidic cyclization of aliphatic and partially cyclized C15–C25 terpenoid acids and their esters proceeds structure-selectively and stereospecifically, affording a-isomers of completely cyclized epimeric ß,?-unsaturated acids or esters; the configuration of their carboxylic or ester groups is predetermined by the configuration of the double bond conjugated with the carboxyl or ester groups in the starting compounds.

P. F. Vlad; N. D. Ungur; Nguen Tuen

1995-01-01

21

Sulfonated branched chain fatty acids and esters  

Microsoft Academic Search

In continuation of work reported a year ago describing branched chain fatty acids, a series of monosodium methyl 2-sulfo-2-alkylalkanoates\\u000a [RR'C (SO3Na) CO2CH3] were synthesized. The surface active properties of these compounds were evaluated and compared with the corresponding disodium\\u000a 2-sulfo-2-alkylalkanoates [RR'C (SO3Na)CO2Na]. Alkaline hydrolysis rates show that the sodium methyl esters are stable. Relative to the disodium salts, these compounds

T. J. Micich; E. A. Diamond; R. G. Bistline; A. J. Stirton; W. C. Ault

1966-01-01

22

Complexes of Alkyl Esters of Ethylidenediphosphonic Acids with Lanthanide Nitrates  

Microsoft Academic Search

The lanthanide complexes LnL2(NO3)33a?c and 5a?c, where Ln is La, Ce and Sm and L are tetraethyl esters of ethylidenediphosphonic acid 1 (for complexes 3) and tetraisopropyl esters of ethylidenediphosphonic acid 4 (for complexes 5) were synthesized and characterized by elemental analysis, IR and NMR spectroscopy. The crystal structure of DyL2(NO3)37 (L is tetraisopropyl ester of methylenediphosphonic acid) was determined

Vladislav Arabadzhiev; Jordanka Petrova; Erhard T. K. Haupt; Jürgen Kopf; Isabelle Nevoigt

2008-01-01

23

?-Sulfonated fatty acids and esters: Manufacturing process, properties, and applications  

Microsoft Academic Search

?-Sulfonated fatty acid esters, because of their wide-range of application and biological properties, represent an interesting\\u000a class of surfactants. A technical method for the preparation of ?-sulfonated fatty acid esters is described. By using special\\u000a reaction conditions it is possible to ?-sulfonate saturated fatty esters directly without the use of solvents. The use of\\u000a gaseous SO3 gives the product in

W. Stein; H. Baumann

1975-01-01

24

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...

25

Phenylpropanoid acid esters from Korean propolis and their antioxidant activities.  

PubMed

Ten phenylpropanoic acid esters were isolated from an ethanolic extract of Korean propolis. Their structures were elucidated by spectroscopic methods including NMR and ESI-MS. Caffeic acid esters with catechol moiety exhibited significant ABTS and DPPH radical scavenging activity and protective effect against DNA damage by a Fenton reaction. PMID:24928402

Lee, In-Kyoung; Han, Myung-Suk; Kim, Dae-Won; Yun, Bong-Sik

2014-08-01

26

Superacid cyclization of esters of some bishomoisoprenoid acids  

Microsoft Academic Search

It is shown that on the superacid cyclization of esters of bishomobicyclogeranylgeranic and E,E-bishomofarnesic acids fully\\u000a cyclized hydroxyesters are formed in good yield, while on the interaction of esters of 6-hydroxy- and 6-acyloxy-15-bishomobicyclogeranylgeranic\\u000a acids with a superacid no carbocyclization takes place.

N. D. Ungur; Nguen Van Tuen; N. P. Popa; P. F. Vlad

1992-01-01

27

Collagenase inhibitory quinic acid esters from Ipomoea pes-caprae.  

PubMed

Two new quinic acid esters (1 and 2) were isolated from the extract of Ipomoea pes-caprae together with six known quinic acid esters (3-8). The structures of compounds 1 and 2 were elucidated by spectroscopic data interpretation. These new compounds exhibited collagenase inhibitory activity and showed almost no cytotoxicity. PMID:15921434

Teramachi, Fumihiro; Koyano, Takashi; Kowithayakorn, Thaworn; Hayashi, Masahiko; Komiyama, Kanki; Ishibashi, Masami

2005-05-01

28

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

29

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

Code of Federal Regulations, 2011 CFR

...acid ester, substituted amine salt. 721.7770 Section 721...acid ester, substituted amine salt. (a) Chemical substance...acid ester, substituted amine salt (PMN P-92-396) is subject...k). (iii) Release to water. Requirements as...

2011-07-01

30

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

Code of Federal Regulations, 2013 CFR

...acid ester, substituted amine salt. 721.7770 Section 721...acid ester, substituted amine salt. (a) Chemical substance...acid ester, substituted amine salt (PMN P-92-396) is subject...k). (iii) Release to water. Requirements as...

2013-07-01

31

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

Code of Federal Regulations, 2010 CFR

...true Partial phosphoric acid esters of polyester resins. 175.260 Section 175.260...260 Partial phosphoric acid esters of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section...

2010-04-01

32

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

Code of Federal Regulations, 2011 CFR

...false Partial phosphoric acid esters of polyester resins. 175.260 Section 175.260...260 Partial phosphoric acid esters of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section...

2011-04-01

33

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

Code of Federal Regulations, 2010 CFR

... Lactylated fatty acid esters of glycerol and propylene glycol. 172.850... Lactylated fatty acid esters of glycerol and propylene glycol. The food...additive lactylated fatty acid esters of glycerol and propylene glycol may be...

2010-04-01

34

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

...2014-04-01 false Lactylated fatty acid esters of glycerol and propylene glycol...Additives § 172.850 Lactylated fatty acid esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene...

2014-04-01

35

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

...2014-04-01 false Partial phosphoric acid esters of polyester resins. 175.260...Coatings § 175.260 Partial phosphoric acid esters of polyester resins. Partial phosphoric acid esters of polyester resins identified...

2014-04-01

36

21 CFR 184.1101 - Diacetyl tartaric acid esters of mono- and diglycerides.  

...2014-04-01 false Diacetyl tartaric acid esters of mono- and diglycerides. 184...GRAS § 184.1101 Diacetyl tartaric acid esters of mono- and diglycerides. (a) Diacetyl tartaric acid esters of mono- and...

2014-04-01

37

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

...2014-04-01 2014-04-01 false Polyhydric alcohol esters of long chain monobasic acids...Production Aids § 178.3780 Polyhydric alcohol esters of long chain monobasic acids. Polyhydric alcohol esters of long chain monobasic...

2014-04-01

38

Triterpene hexahydroxydiphenoyl esters and a quinic acid purpurogallin carbonyl ester from the leaves of Castanopsis fissa  

Microsoft Academic Search

Triterpene hexahydroxydiphenoyl (HHDP) esters have only been isolated from Castanopsis species, and the distribution of these esters in nature is of chemotaxonomical interest. In this study, the chemical constituents of the leaves of Castanopsis fissa were examined in detail to identify and isolate potential HHDP esters. Together with 53 known compounds, 3,4-di-O-galloyl-1-O-purpurogallin carbonyl quinic acid (1) and 3,24-(S)-HHDP-2?,3?,23,24-tetrahydroxytaraxastan-28,20?-olide (2) were

Yong-Lin Huang; Takaaki Tsujita; Takashi Tanaka; Yosuke Matsuo; Isao Kouno; Dian-Peng Li; Gen-ichiro Nonaka

2011-01-01

39

Effect of formic acid and benzoic acid esters on grass preservation  

E-print Network

alternatives for benzoic acid and propionic acid was the high prices of these components. The esters of benzoicEffect of formic acid and benzoic acid esters on grass preservation A Rauramaa A Tommila J Ltd, Espoo Reseach Centre, PO Box 44, 02271 Espoo, Finland Formic acid is known to improve silage

Paris-Sud XI, Université de

40

ESTIMATION OF CARBOXYLIC ACID ESTER HYDROLYSIS RATE CONSTANTS  

EPA Science Inventory

SPARC chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid esters from molecular structure. The energy differences between the initial state and the transition state for a molecule of interest are factored into internal and external...

41

Triterpene hexahydroxydiphenoyl esters and a quinic acid purpurogallin carbonyl ester from the leaves of Castanopsis fissa.  

PubMed

Triterpene hexahydroxydiphenoyl (HHDP) esters have only been isolated from Castanopsis species, and the distribution of these esters in nature is of chemotaxonomical interest. In this study, the chemical constituents of the leaves of Castanopsis fissa were examined in detail to identify and isolate potential HHDP esters. Together with 53 known compounds, 3,4-di-O-galloyl-1-O-purpurogallin carbonyl quinic acid (1) and 3,24-(S)-HHDP-2?,3?,23,24-tetrahydroxytaraxastan-28,20?-olide (2) were isolated and their structures were elucidated by spectroscopic and chemical methods. The polyphenols of the leaves were mainly composed of galloyl quinic acids, triterpenes HHDP esters, ellagitannins and flavonol glycosides. In particular, the isolation yields of 1,3,4-trigalloyl quinic acid and compound 2 were 1.53% and 0.27%, respectively, from the fresh leaves. The presence of lipid soluble HHDP esters of oleanane-type triterpenes as one of the major metabolites is an important chemotaxonomical discovery. Lipase inhibition activities and ORAC values of the major constituents were compared. The triterpene HHDP ester showed moderate lipase inhibition activity and myricitrin gave the largest ORAC value. PMID:21831402

Huang, Yong-Lin; Tsujita, Takaaki; Tanaka, Takashi; Matsuo, Yosuke; Kouno, Isao; Li, Dian-Peng; Nonaka, Gen-ichiro

2011-11-01

42

[Cutaneous and pulmonary sarcoidosis. Successful therapy with fumaric acid esters].  

PubMed

A 43-year-old man with cutaneous and pulmonary sarcoidosis was treated with fumaric acid esters (Fumaderm®) for 11 months because of the cutaneous lesions. During the treatment the cutaneous lesions and pulmonary changes vanished completely. In addition, serum angiotensin converting enzyme (ACE) levels normalized after end of therapy. This case report is one of a few examples of the successful treatment of cutaneous and pulmonary sarcoidosis with fumaric acid esters (Fumaderm®). PMID:22552842

Wolter, A; Müller, M; Völker, B; Gehring, M; Caldarone, F; Kapp, A; Werfel, T; Raap, U

2012-10-01

43

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

44

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; Hölzl, Georg; Wewer, Vera; Yilmaz, Jenny Lindberg; Lager, Ida; Montandon, Cyrille; Besagni, Céline; Kessler, Felix; Stymne, Sten; Dörmann, Peter

2012-05-01

45

Preparation of ester of alkenylsuccinic acid and oxyethylated alkylphenol  

SciTech Connect

This paper investigates the esterification of alkenylsuccinic acid (ASA) with an oxyethylated alkyphenol (OEP) and investigates the protective efficiency of the ester products. It is shown that the physicochemical properties and the protective efficiency of the ester products are influenced by the conditions of its synthesis. The ester obtained with a ratio of c /SUB ASA/ : c /SUB OEP/ = 1:1 has the best protective properties, thermal stability, and oil solubility. This is apparently related to the fact that the final product does not contain any alkylphenol, which is less thermally stable and is more deficient in terms of thin-film protective properties. The oxyethylated ester of alkenylsuccinic acid is being used as one of the components of highly effective ashless corrosion inhibitors; and as part of these corrosion inhibitors, it is used in operational/preservative oils for various engines, gear, and transmission components.

Mikhailova, O.L.; Shekhter, Y.N.; Vigant, G.T.; Vigant, V.V.

1986-09-01

46

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

...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 §...

2014-07-01

47

21 CFR 178.3770 - Polyhydric alcohol esters of oxidatively refined (Gersthofen process) montan wax acids.  

... 2014-04-01 false Polyhydric alcohol esters of oxidatively refined (Gersthofen...Production Aids § 178.3770 Polyhydric alcohol esters of oxidatively refined (Gersthofen process) montan wax acids. Polyhydric alcohol esters of oxidatively refined...

2014-04-01

48

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

PubMed Central

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

2013-01-01

49

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

50

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 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...

2011-07-01

51

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 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...

2012-07-01

52

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 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...

2013-07-01

53

40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.  

Code of Federal Regulations, 2010 CFR

... false Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester...721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester...identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl...

2010-07-01

54

A corollary to the silicic acid leakage hypothesis  

Microsoft Academic Search

The silicic acid leakage hypothesis (SALH) attempts to explain part of the large and regular atmospheric CO2 changes over the last glacial-interglacial cycles. It calls for a reduction in the carbonate pump through a growth in diatoms at the expense of coccolithophorids in low-latitude surface waters, driven by a “leakage” of high-Si:N waters from the Southern Ocean. Recent studies that

Katsumi Matsumoto; Jorge L. Sarmiento

2008-01-01

55

Electron driven processes in chlorodifluoroacetic acid methyl ester  

NASA Astrophysics Data System (ADS)

Dissociative electron attachment to gas phase 2-chloro-2,2-difluoroacetic acid methyl ester (CClF2COOCH3) is studied by means of a crossed beams apparatus. Effective cleavage of the C-Cl bond is observed within a broad resonance in the energy range 0-1 eV and visible via the appearance of the light fragment Cl-. In chlorodifluoroacetic acid cleavage of the C-Cl bond was observed not only via the Cl- anion formation but predominantly via expulsion of the neutral chlorine atom leading to the formation of the (M-Cl)- anion. Similar to the previously studied esters CF3COOCH3 and CF3COOC2H5[I. Martin, J. Langer, E. Illenberger, Z. Phys. Chem. 222, 1185 (2008)], we observe reaction due to the cleavage of the ester bond resulting in the formation of the closed shell (M-CH3)- anion.

Kopyra, Janina

2014-07-01

56

Dielectric properties of biodegradable polylactic acid and starch ester  

Microsoft Academic Search

In order to examine the applicability of biodegradable polymers to the fields of electrical insulation, several dielectric properties of two typical biodegradable polymers, polylactic acid (PLA) and starch ester (SE), are examined. A fairly larger amount of space charge is accumulated in both polymers in comparison to low-density polyethylene (LDPE). This seems partly due to the presence of hydroxyl and

N. Hirail; Y. Maeno; H. Tamura; D. Kaneko; T. Tanaka; Y. Ohki; Y. Tajitsu; M. Kohtoh; S. Okabe

2004-01-01

57

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

58

78 FR 46283 - Modification of Significant New Uses of Ethaneperoxoic Acid, 1,1-Dimethylpropyl Ester  

Federal Register 2010, 2011, 2012, 2013

...Modification of Significant New Uses of Ethaneperoxoic Acid, 1,1- Dimethylpropyl Ester AGENCY: Environmental Protection Agency...the chemical substance identified as ethaneperoxoic acid, 1,1- dimethylpropyl ester, which was the subject of...

2013-07-31

59

Transferable force field for carboxylate esters: application to fatty acid methylic ester phase equilibria prediction.  

PubMed

In this work, a new transferable united-atoms force field for carboxylate esters is proposed. All Lennard-Jones parameters are reused from previous parametrizations of the AUA4 force field, and only a unique set of partial electrostatic charges is introduced for the ester chemical function. Various short alkyl-chain esters (methyl acetate, ethyl acetate, methyl propionate, ethyl propionate) and two fatty acid methylic esters (methyl oleate and methyl palmitate) are studied. Using this new force field in Monte Carlo simulations, we show that various pure compound properties are accurately predicted: saturated liquid densities, vapor pressures, vaporization enthalpies, critical properties, liquid-vapor surface tensions. Furthermore, a good accuracy is also obtained in the prediction of binary mixture pressure-composition diagrams, without introducing empirical binary interaction parameters. This highlights the transferability of the proposed force field and gives the opportunity to simulate mixtures of industrial interest: a demonstration is performed through the simulation of the methyl oleate + methanol mixture involved in the purification sections of biodiesel production processes. PMID:22369235

Ferrando, Nicolas; Lachet, Véronique; Boutin, Anne

2012-03-15

60

Gas chromatographic analysis of fatty acid methyl esters  

Microsoft Academic Search

The full process of fatty acid methyl ester (FAME) analysis consists of esterification of lipids, and of injection, separation, identification and quantitation of the FAMEs. In order for the required accuracy and precision to be attained, each of these steps has to be optimized.Esterification of lipids can be carried out with several reagents based on acid-catalysed or base-catalysed reactions. The

K. Eder

1995-01-01

61

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

62

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

63

Synthesis of Alkyl Methylphosphonic Acid Esters  

SciTech Connect

This manuscript describes a simple synthesis and purification of cyclohexyl methylphosphonic and isopropyl methylphosphonic acids that provides high purity (>95% purity) product in gram quantities. Based on needs for improved analytical methods for indirect detection of nerve agent use, there is an increasing demand for these nerve agent hydrolysis products. These products are not commercially available. Synthesis is based on reaction of equimolar amounts of alcohol with methylphosphonic dichloride in toluene followed by the addition of excess water (two mole equivalents). The product was then extracted from the resulting aqueous layer into chloroform. The extraction scheme proved highly effective in removing unreacted starting materials and reaction by-products.

Mong, Gary M.; Harvey, Scott D.; Campbell, James A.

2005-08-01

64

Performance and physicochemical properties of ?-sulfo fatty acid methyl esters  

Microsoft Academic Search

The detergency properties of ?-sulfonated fatty acid methyl esters (?-SFMe) were evaluated and compared to those of conventional\\u000a anionic surfactants by using a model heavy-duty detergent formulation. Several physicochemical properties of surfactants were\\u000a measured to investigate the effective factors on detergency. ?-SFMe showed good detergency performance under various washing\\u000a conditions. These results were considered to correlate well with the good

Teruhisa Satsuki; Kenji Umehara; Yuji Yoneyama

1992-01-01

65

Evaluation of salicylic acid fatty ester prodrugs for UV protection.  

PubMed

The purpose of this study was to investigate the physicochemical properties and in vitro evaluation of fatty ester prodrugs of salicylic acid for ultraviolet (UV) protection. The physicochemical properties such as lipophilicity, chemical stability and enzymatic hydrolysis were investigated with the following fatty ester prodrugs of salicylic acid: octanoyl (C8SA), nonanoyl (C9SA), decanoyl (C10SA), lauroyl (C12SA), myristoyl (C14SA) and palmitoyl oxysalicylate (C16SA). Furthermore, their skin permeation and accumulation were evaluated using a combination of common permeation enhancing techniques such as the use of a lipophilic receptor solution, removal of stratum corneum and delipidization of skin. Their k' values were proportional to the degree of carbon-carbon saturation in the side chain. All these fatty esters were highly stable in 2-propanol, acetonitrile and glycerin, but unstable in methanol and ethanol. They were relatively unstable in liver and skin homogenates. In particular, C16SA was mostly hydrolyzed to its parent compound in hairless mouse liver and skin homogenates, suggesting that it might be converted to salicylic acid after its topical administration. In the skin permeation and accumulation study, C16SA showed the poorest permeation in all skins, suggesting that it could not be permeated in the skin. Furthermore, C14SA and C16SA were less accumulated in delipidized skin compared with normal skin or stripped skin, suggesting that these esters had relatively strong affinities for lipids compared with the other prodrugs in the skin. C16SA showed significantly higher dermal accumulation in all skins compared with its parent salicylic acid. Thus, the palmitoyl oxysalicylate (C16SA) might be a potential candidate for UV protection due to its absence of skin permeation, smaller uptake in the lipid phase and relatively lower skin accumulation. PMID:21244220

Im, Jong Seob; Balakrishnan, Prabagar; Oh, Dong Hoon; Kim, Jung Sun; Jeon, Eun-Mi; Kim, Dae-Duk; Yong, Chul Soon; Choi, Han-Gon

2011-07-01

66

Changes in Esters of Fatty Acids of Rhizopus arrhizus During Germination and Growth  

PubMed Central

Natural esters of fatty acids of Rhizopus arrhizus Fischer increased during the first 48 hr of growth. During the 48- to 72-hr period, there was a shift in concentration from the methyl esters to the ethyl esters of fatty acids. PMID:5079078

Hess, S. L.; Weber, D. J.; Gunasekaran, M.

1972-01-01

67

Fatty Acid methyl ester profiles of bat wing surface lipids.  

PubMed

Sebocytes are specialized epithelial cells that rupture to secrete sebaceous lipids (sebum) across the mammalian integument. Sebum protects the integument from UV radiation, and maintains host microbial communities among other functions. Native glandular sebum is composed primarily of triacylglycerides (TAG) and wax esters (WE). Upon secretion (mature sebum), these lipids combine with minor cellular membrane components comprising total surface lipids. TAG and WE are further cleaved to smaller molecules through oxidation or host enzymatic digestion, resulting in a complex mixture of glycerolipids (e.g., TAG), sterols, unesterified fatty acids (FFA), WE, cholesteryl esters, and squalene comprising surface lipid. We are interested if fatty acid methyl ester (FAME) profiling of bat surface lipid could predict species specificity to the cutaneous fungal disease, white nose syndrome (WNS). We collected sebaceous secretions from 13 bat spp. using Sebutape(®) and converted them to FAME with an acid catalyzed transesterification. We found that Sebutape(®) adhesive patches removed ~6× more total lipid than Sebutape(®) indicator strips. Juvenile eastern red bats (Lasiurus borealis) had significantly higher 18:1 than adults, but 14:0, 16:1, and 20:0 were higher in adults. FAME profiles among several bat species were similar. We concluded that bat surface lipid FAME profiling does not provide a robust model predicting species susceptibility to WNS. However, these results provide baseline data that can be used for lipid roles in future ecological studies, such as life history, diet, or migration. PMID:25227993

Pannkuk, Evan L; Fuller, Nathan W; Moore, Patrick R; Gilmore, David F; Savary, Brett J; Risch, Thomas S

2014-11-01

68

Synthesis and Testing of Phosphoric Acid Esters Obtained on a Base of Cyclohexanol Derivatives.  

National Technical Information Service (NTIS)

Five phosphoric acid esters were synthesized on the basis of cyclohexanol derivatives; analysis results show that the elemental composition of these esters is close to the calculated theoretical level. Preliminary studies of the synthesized compounds show...

I. M. Orudzheva, S. M. Novruzov

1971-01-01

69

Effect of organic acid vapors on the alteration of soda silicate glass  

Microsoft Academic Search

Organic acids were previously shown to be involved in the alteration of historic soda silicate glasses in humid atmospheres under museum storage conditions. The present study investigates the role of these pollutants on the visual, compositional and structural modification of soda silicate glasses. Replica glasses aged in humid or humid\\/acidic atmospheres under accelerated conditions were examined and compared using light

Laurianne Robinet; Katherine Eremin; Claude Coupry; Christopher Hall; Nelly Lacome

2007-01-01

70

Silicic acid leakage from the Southern Ocean: Opposing effects of nutrient uptake and oceanic circulation  

E-print Network

in the Antarctic and Subantarctic zones whereby changes in the phytoplankton community from diatoms to non the silicic acid content of Antarctic surface waters in determining the magnitude of silicic acid leakage from favoring the growth of diatoms over calcifying phytoplankton at low latitudes. [3] The SALH is composed

Pahnke, Katharina

71

Effect of iron deficiency on diatom cell size and silicic acid uptake kinetics  

Microsoft Academic Search

We studied the silicic acid uptake kinetics of the pennate diatom Cylindrotheca fusiformis grown under a wide range of iron concentrations (from Fe-limiting to Fe-sufficient conditions) to assess the effect of iron availability on diatom cell size, silicon content, and silicic acid uptake kinetic parameters. As the iron stress increased, the growth rate slowed, cell size decreased, and silicification increased.

A. Leynaert; E. Bucciarelli; P. Claquin; R. C. Dugdale; V. Martin-Jézéquel; P. Pondaven; O. Ragueneau

2004-01-01

72

Fluorophilicity of Alkyl and Polyfluoroalkyl 1 Nicotinic Acid Ester Prodrugs  

PubMed Central

The fluorophilicity of a series of hydrocarbon and fluorocarbon-functionalized nicotinic acid esters (nicotinates) is measured from their partitioning behavior (log KP) in the biphasic solvent system of perfluoro(methylcyclohexane) (PFMC) and toluene. The chain length of the hydrocarbon or fluorocarbon alkyl group of the ester ranges from one to twelve carbon atoms. Knowledge of the fluorophilicity of these solutes is relevant to the design of these prodrugs for fluorocarbon-based drug delivery. The experimental log Kp values range from ?1.72 to ?3.40 for the hydrocarbon nicotinates and ?1.64 to 0.13 for the fluorinated nicotinates, where only the prodrug with the longest fluorinated chain (2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl nicotinic acid ester) partitions preferentially into the fluorinated phase (log Kp = 0.13). Predictions of the partition coefficients using solubility parameters calculated from group contribution techniques or molecular dynamics simulation are in reasonable agreement for the perhydrocarbon nicotinates and short chained perfluorinated nicotinates (? 0.3%-39% deviation). Significant deviations from experimental partition coefficients (greater than 100%) are observed for the longest chain perfluoroalkyl nicotinates. PMID:20567608

Ojogun, Vivian; Knutson, Barbara L; Vyas, Sandhya; Lehmler, Hans-Joachim

2010-01-01

73

Physicochemical properties of ambiently dried sodium silicate based aerogels catalyzed with various acids  

Microsoft Academic Search

Experimental results on the physico-chemical properties of ambiently dried sodium silicate based aerogels catalyzed with various\\u000a acids are reported. The aerogels were prepared by hydrolysis and polycondensation of sodium silicate followed by subsequent\\u000a washings, surface chemical modification and ambient pressure drying using 10 various acid catalysts consisting of strong and\\u000a weak acids. The strength and concentration of acids have the

Uzma K. H. Bangi; A. Parvathy Rao; H. Hirashima; A. Venkateswara Rao

2009-01-01

74

21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.  

...false Methyl and ethyl esters of fatty acids produced from edible fats and oils. ...225 Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils...

2014-04-01

75

21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.  

Code of Federal Regulations, 2012 CFR

...ethyl esters of fatty acids produced from edible fats and oils. 172.225 Section...ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils may be safely used in...

2012-04-01

76

21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.  

Code of Federal Regulations, 2013 CFR

...ethyl esters of fatty acids produced from edible fats and oils. 172.225 Section...ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils may be safely used in...

2013-04-01

77

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

78

ESTIMATION OF HYDROLYSIS RATE CONSTANTS OF CARBOXYLIC ACID ESTER AND PHOSPHATE ESTER COMPOUNDS IN AQUEOUS SYSTEMS FROM MOLECULAR STRUCTURE BY SPARC  

EPA Science Inventory

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 structure. The energy diffe...

79

The solubilization of some local anaesthetic ester of p-aminobenzoic acid by lysophosphatidylcholine.  

PubMed

The solubilization by lysophosphatidylcholine (LPC) of three n-alkyl esters of p-aminobenzoic acid has been studied. These esters have a local anaesthetic action. Quantitative studies show that the amount of compound solubilized is proportional to the LPC concentration and that solubilization increases in the order ethyl, n-propyl and n-butyl ester. 100MHz nmr studies indicate that the local anaesthetic esters are solubilized in the hydrocarbon interior of the LPC. PMID:237071

Hunt, M J; Saunders, L

1975-02-01

80

Toxicokinetics of Phthalic Acid: The Common Final Metabolite of Phthalic Acid Esters in Rats  

Microsoft Academic Search

The toxicokinetic profiles of phthalic acid (PA), which is the common final metabolite of phthalic acid esters (PAE), were studied in rats after orally administering doses 20, 100, or 500 mg\\/kg. Concentrations of PA were determined in serum or urine by high-performance liquid chromatography (HPLC). The plasma concentrations of PA showed a biexponential increase following oral administration of doses ranging

Duck Soo Lim; Bum Soo Shin; Sun Dong Yoo; Hyung Sik Kim; Seung Jun Kwack; Mi Young Ahn; Byung Mu Lee

2007-01-01

81

Inactive Methyl Indole-3-Acetic Acid Ester Can Be Hydrolyzed and Activated by Several Esterases Belonging  

E-print Network

(salicylic acid binding protein 2) hydrolyzes methyl salicylate to salicylic acid. There are 20 homologsInactive Methyl Indole-3-Acetic Acid Ester Can Be Hydrolyzed and Activated by Several Esterases, and peptides. We have recently shown that IAA could be converted to its methyl ester (MeIAA) by the Arabidopsis

Pichersky, Eran

82

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. PMID:16461689

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

2006-01-01

83

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

Microsoft Academic Search

Summary  Adsorption 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

84

Inhibition of hepatic glutathione-S-transferases by fatty acids and fatty acid esters.  

PubMed

Micromolar concentrations of polyunsaturated fatty acids and ascorbate esters of saturated fatty acids were found to cause a marked inhibition of rat and mouse hepatic glutathione-S-transferase (GST) activity towards 1-chloro-2,4-dinitrobenzene. Arachidonic acid was approximately 25 times more potent in inhibiting rat GST than palmitic acid which was the least effective. Both linoleic and arachidonic acids did not inhibit rat liver GST when ethacrynic acid was used as substrate while the reverse was true with 1,2-dichoro-4-nitrobenzene. In contrast, all the chemicals tested inhibited rat liver GST activity towards 4-nitropyridine N-oxide, indicating isozyme specificity. PMID:1949072

Mitra, A; Govindwar, S; Kulkarni, A P

1991-10-01

85

Intramolecular interactions in ortho-methoxyalkylphenylboronic acids and their catechol esters.  

PubMed

Catechol esters of ortho-methoxyalkylphenylboronic acids have been synthesized and characterized by (17)O NMR spectroscopy. The results were compared with the data for the parent acids. The influence of intramolecular and intermolecular hydrogen bonds on the properties of the boronic acids has been discussed. The (17)O NMR data for the boronic esters proved that there are no O ? B interactions in the investigated compounds. This fact is connected with weak Lewis acidity of the parent acids and their low sugars' receptors activity. Crystal structure of ortho-methoxyphenylboronic acid catechol ester was determined. PMID:23978747

Adamczyk-Wo?niak, Agnieszka; Borys, Krzysztof M; Czerwi?ska, Karolina; Gierczyk, B?a?ej; Jakubczyk, Micha?; Madura, Izabela D; Sporzy?ski, Andrzej; Tomecka, Ewelina

2013-12-01

86

Enzymatic production of bioactive docosahexaenoic acid phenolic ester.  

PubMed

Docosahexaenoic acid (DHA) is increasingly considered for its health benefits. However, its use as functional food ingredient is still limited by its instability. In this work, we developed an efficient and solvent-free bioprocess for the synthesis of a phenolic ester of DHA. A fed-batch process catalyzed by Candida antarctica lipase B was optimised, leading to the production of 440g/L vanillyl ester (DHA-VE). Structural characterisation of the purified product indicated acylation of the primary OH group of vanillyl alcohol. DHA-VE exhibited a high radical scavenging activity in acellular systems. In vivo experiments showed increased DHA levels in erythrocytes and brain tissues of mice fed DHA-VE-supplemented diet. Moreover, in vitro neuroprotective properties of DHA-VE were demonstrated in rat primary neurons exposed to amyloid-? oligomers. In conclusion, DHA-VE synergized the main beneficial effects of two common natural biomolecules and therefore appears a promising functional ingredient for food applications. PMID:25308686

Roby, Mohamed H; Allouche, Ahmad; Dahdou, Layal; De Castro, Vanessa C; Alves da Silva, Paulo H; Targino, Brenda N; Huguet, Marion; Paris, Cédric; Chrétien, Françoise; Guéant, Rosa-Maria; Desobry, Stéphane; Oster, Thierry; Humeau, Catherine

2015-03-15

87

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

88

Enzymatic synthesis of a galactopyranose sophorolipid fatty acid-ester  

Microsoft Academic Search

Sophorolipid lactones produced by Candida bombicola were deacetylated and ring opened with sodium methoxide to their corresponding methyl esters. The methyl esters, after re-acetylation with vinyl acetate using an immobilized lipase, were transesterified with 1,2-3,4-di-O-isopropylidene-d-galactopyranose in tetrahydrofuran using the same lipase catalyst. The di-O-isopropylidene sophorolipid sugar esters were hydrolyzed to give the galactopyranose sophorolipid esters as the final products.

Alberto Nuñez; Thomas A. Foglia; Richard Ashby

2003-01-01

89

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

90

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

21 Food and Drugs 3 2014-04-01 2014-04-01...Glyceryl-lacto esters of fatty acids. 172.852 Section 172.852 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...Glyceryl-lacto esters of fatty acids. Glyceryl-lacto...

2014-04-01

91

Colloidal properties of ?-sulfonated fatty acid methyl esters and their applicability in hard water  

Microsoft Academic Search

The calcium salts of a-sulfonated fatty acid methyl esters were prepared, and the physico-chemical properties such as solubility, critical micelle concentration, aggregation number, and precipitation phase boundary were studied to clarify the reasons for the good hardness tolerance manifested by a-sulfonated fatty acid methyl esters.

Masami Fujiwara; M. Miyake; Y. Abe

1993-01-01

92

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 720 mg daily, with complete remission of the psoriatic lesions and neurological stabilization at follow-up at 24 months. 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

93

Analysis of phytostanyl fatty acid esters in enriched foods via UHPLC-APCI-MS.  

PubMed

A method for the analysis of phytostanyl fatty acid esters, the functional ingredients of cholesterol-lowering enriched foods, was developed. The procedure is based on (i) separation of the intact esters via reversed-phase ultrahigh-performance liquid chromatography; (ii) detection by atmospheric pressure chemical ionization-mass spectrometry; and (iii) quantitation using selected ion monitoring (SIM) mode. Employing a C8 column, phytostanyl fatty acid esters sharing the same stanol nucleus could be separated according to the esterified fatty acids while esters with different stanol moieties could be distinguished via SIM based on the formation of an intense fragment ion [M - fatty acid + H](+). The suitability of the approach was demonstrated using different types of enriched foods reflecting the diversity in potential matrices (skimmed milk drinking yogurt, margarine, and soft-cheese-style spread). The developed methodology extends the analytical basis for authenticity and quality assessments of functional foods enriched with phytostanyl fatty acid esters. PMID:24766184

Scholz, Birgit; Barnsteiner, Andreas; Feist, Katharina; Schmid, Wolfgang; Engel, Karl-Heinz

2014-05-14

94

Selective synthesis of either isoindole- or isoindoline-1-carboxylic acid esters by Pd(0)-catalyzed enolate arylation.  

PubMed

Two efficient palladium-catalyzed intramolecular ?-arylation reactions of ?-amino acid esters have been developed that allow either 1-isoindolecarboxylic acid esters or the corresponding isoindolines to be selectively synthesized simply by a slight change of reaction conditions. PMID:20738127

Solé, Daniel; Serrano, Olga

2010-09-17

95

Polymerization of Fatty Acid Methyl Ester Using Acidic Ionic Liquid as Catalyst  

Microsoft Academic Search

The polymerization of fatty acid methyl ester was investigated using biodiesel as the feed in the presence of a Brönsted-Lewis acidic ionic liquid (IL). A synergetic effect of Brönsted and Lewis acid sites enhanced the catalytic performance of the IL. 1-(3-Sulfonic acid)-propyl-3-methylimidazole chlorozincinate ([HO3S-(CH2)3-mim]Cl-ZnCl2, molar fraction of ZnCl2 was 0.67) was an efficient catalyst for the polymerization. The effects of

Shiwei LIU; Lu LI; Shitao YU; Congxia XIE; Fusheng LIU; Zhanqian SONG

2010-01-01

96

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

Federal Register 2010, 2011, 2012, 2013

...FRL-8436-3] Polyglyceryl Phthalate Ester of Coconut Oil Fatty Acids; Exemption from the Requirement...concerning polyglyceryl phthalate ester of coconut oil fatty acids; exemption from the requirement...for ``polyglyceryl phthalate ester of coconut oil fatty acids'' pursuant to a...

2010-04-21

97

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. PMID:23186551

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

2012-01-01

98

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

99

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

100

[Studies on the role of silicic acid in the development of higher plants].  

PubMed

Germanium acid, a specific inhibitor of the silicic acid metabolism in diatoms, inhibits the growth of Sinapis alba, Lemna minor, Wolffia arrhiza, Nicotiana tabacum, Tradescantia spec, Zinnia elegans, and Secale cereale when applied in the same concentrations as those used in the case of diatoms (15-75 ?g GeO2/ml medium). The growth of Aspergillus niger, Phycomyces blakesleanus, Escherichia coli K 12, Euglena gracilis and Pandorina morum is not influenced by these and higher concentrations of Germanium acid. By application of high concentrations of silicic acid, the growth inhibition produced by germanium acid in Lemna minor is partially reduced. Plants of Lemna minor which have been inhibited by germanium acid are essentially smaller than plants grown in a normal medium; their chlorophyll content is significantly decreased. The growth of the roots in Lemna is particularly inhibited. Isolated growing roots of Lycopersicon pimpinellifolium MILL. are inhibited by small concentrations of Ge(OH)4 (ca. 1,5×10(-4) M/l). In contrast to the growth of older plants, the germination of Secale cereale and Sinapis alba is not influenced by Ge(OH)4. The effects of germanium acid are discussed in relation to the physiological role of silicic acid. The results suggest that the element silicon, in the form of silicic acid, is generally essential for the normal development of higher plants. PMID:24549376

Werner, D

1967-03-01

101

An Investigation of Ester Group Steric Effects on Metal Ion Extraction by Symmetrically Substituted Methylenediphosphonic Acids  

Microsoft Academic Search

Symmetrically substituted partial alkyl?esters of methylenediphosphonic acid are powerful metal ion extractants for actinides in all oxidation states. A preliminary study of calcium and americium(III) extraction by the n?octyl and 2?ethylhexyl di?substituted esters of methylenediphosphonic acid revealed the distribution ratios and the nitric acid dependency behaviors for the two extractants to be very similar, with the extraction efficiency for the

D. C. Stepinski; D. R. McAlister; P. R. Zalupski; R. Chiarizia; A. W. Herlinger

2004-01-01

102

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. PMID:3830106

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

1986-01-01

103

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

104

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. PMID:24991246

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

2014-01-01

105

The effect of benzoic acid or its ethyl ester on rumen fermentation parameters  

E-print Network

The effect of benzoic acid or its ethyl ester on rumen fermentation parameters J Nousiainen Valio be used as mould and yeast inhibitors in silage additives to improve the aerobic stability of silage response of BA or its ethyl ester (EB) on the rumen fermentation parameters in the continuous culture

Paris-Sud XI, Université de

106

Preparation of fatty acid methyl ester through temperature gradient driven pervaporation process  

Microsoft Academic Search

Fatty acid esters are useful functional molecules in pharmaceutical, cosmetic and lubricant industries. The conversion of esters may be enhanced by continuous removal of the water produced during the esterification process which is a reversible reaction. Non-porous hydrophilic pervaporation membranes have the ability to remove water using milder conditions compared to conventional technologies. The potential of pervaporation driven by temperature

Baisali Sarkar; S. Sridhar; K. Saravanan; Vijay Kale

2010-01-01

107

Dimerization of fatty acid methyl ester using Brönsted–Lewis acidic ionic liquid as catalyst  

Microsoft Academic Search

The dimerization of fatty acid methyl ester was investigated using Brönsted–Lewis acidic ionic liquids (ILs) as catalysts. It is found that IL (3-sulfonic acid)-propyl-triethylammonium chlorozincinate [HO3S–(CH2)3–NEt3]Cl–ZnCl2 (x=0.64, x: molar fraction of ZnCl2, x=moles of ZnCl2\\/(moles of ZnCl2+moles of ammonium salt) was of good catalytic performance. Under the optimum conditions m(biodiesel):m(IL) 15:1, biodiesel 15g, reaction temperature 240°C, and reaction time 5h,

Shiwei Liu; Hongxia Zhou; Shitao Yu; Congxia Xie; Fusheng Liu; Zhanqian Song

2011-01-01

108

Polyphenol fatty acid esters as serine protease inhibitors: a quantum-chemical QSAR analysis.  

PubMed

We investigated the ability of polyphenol fatty acid esters to inhibit the activity of serine proteases trypsin, thrombin, elastase and urokinase. Potent protease inhibition in micromolar range was displayed by rutin and rutin derivatives esterified with medium and long chain, mono- and polyunsaturated fatty acids (1e-m), followed by phloridzin and esculin esters with medium and long fatty acid chain length (2a-d, 3a-d), while unmodified compounds showed only little or no effect. QSAR study of the compounds tested provided the most significant parameters for individual inhibition activities, i.e. number of hydrogen bond donors for urokinase, molecular volume for thrombin, and solvation energy for elastase. According to the statistical analysis, the action of elastase inhibitors is opposed to those of urokinase and thrombin. Cluster analysis showed two groups of compounds: original polyphenols together with rutin esters with short fatty acid chain length and rutin esters with long fatty acid chain length. PMID:21981000

Viskupicova, Jana; Danihelova, Martina; Majekova, Magdalena; Liptaj, Tibor; Sturdik, Ernest

2012-12-01

109

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

110

Fatty acid ethyl esters. Ethanol metabolites that reflect ethanol intake.  

PubMed

Fatty acid ethyl esters (FAEEs) are nonoxidative 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 represent markers of ethanol intake. FAEEs have also been quantitated in human liver and adipose tissue and have been shown to be postmortem markers of premortem ethanol intake. A substantial difference in FAEE concentration was found in liver and adipose tissue of patients with detectable blood ethanol at the time of autopsy vs those with no detectable blood ethanol, who were either chronic alcoholics or social drinkers. Most currently available diagnostic markers for chronic alcoholism have limited clinical utility. Data in this report demonstrate that the amount or type of FAEEs can be used to differentiate a chronic alcoholic from an episodic heavy drinker (binage drinker) at or near peak blood ethanol concentrations and approximately 24 hours after discontinuation of ethanol. Thus, FAEEs are markers of ethanol intake in blood and tissues and can be useful in distinguishing chronic alcoholics from binge drinkers. PMID:12951847

Soderberg, Britt L; Salem, Raneem O; Best, Catherine A; Cluette-Brown, Joanne E; Laposata, Michael

2003-06-01

111

Effects of caffeic acid phenethyl ester (CAPE) on hepatopulmonary syndrome.  

PubMed

The aim of this study was to investigate the effects of caffeic acid phenethyl ester (CAPE) on inflammatory and related histopathological changes in the lung and liver in experimental hepatopulmonary syndrome (HPS) model. Forty Sprague Dawley rats were used in this study. The animals were divided into four groups of ten rats each. Group 1 and 2 was subjected the common bile duct (CBD) but not ligated, Group 3; (cirrhosis?+?saline): the CBD was ligated and was given intraperitoneal saline infusion treatment during 5 weeks. Group 4; (cirrhosis?+?CAPE): the CBD was ligated and was given intraperitoneal CAPE infusion treatment during 5 weeks. A 5-week waiting period was observed for the development of cirrhosis and the rats' lungs and liver were taken for histopathological examination. The induction of HPS resulted in a significant increase in serum bilurubin, AST, ALT, and NO levels, and decrease PO2 and O2 saturation. The use of CAPE significant decrease these parameters. Histopathological examination revealed less congestion, portal inflammation, and nodular formations of the liver, and less congestion, emphysematous and inflammatory changes and smallest perialviolar vascular diameters, in the lung in the cirrhosis?+?CAPE groups than in the other groups. CAPE treatment may be a potential approach for the treatment of hepatopulmonary syndrome in the future. PMID:21046212

Tekin, Ahmet; Türky?lmaz, Serdar; Küçükkartallar, Tevfik; Cak?r, Murat; Y?lmaz, Hüseyin; Esen, Hasan; Ate?, Burhan; Ciftci, Ilhan; Kartal, Adil

2011-12-01

112

Production of biodiesel and lactic acid from rapeseed oil using sodium silicate as catalyst.  

PubMed

Biodiesel and lactic acid from rapeseed oil was produced using sodium silicate as catalyst. The transesterification in the presence of the catalyst proceeded with a maximum yield of 99.6% under optimized conditions [3% (w/w) sodium silicate, methanol/oil molar ratio 9/1, reaction time 60 min, reaction temperature 60°C, and stirring rate 250 rpm]. After six consecutive transesterification reactions, the catalyst was collected and used for catalysis of the conversion of glycerol to lactic acid. A maximum yield of 80.5% was achieved when the reaction was carried out at a temperature of 300°C for 90 min. Thus, sodium silicate is an effective catalyst for transesterification and lactic acid production from the biodiesel by-product, glycerol. PMID:21530245

Long, Yun-Duo; Guo, Feng; Fang, Zhen; Tian, Xiao-Fei; Jiang, Li-Qun; Zhang, Fan

2011-07-01

113

Stability studies on methyl and ethyl fatty acid esters of sunflowerseed oil  

Microsoft Academic Search

Fatty acid esters, high in linoleic acid, were prepared and stored for long-term engine tests. Storage tests with these esters\\u000a were undertaken to obtain more information on optimal storage requirements and general stability characteristics.\\u000a \\u000a Samples were kept at three temperature levels (20 C, 30 C and fluctuating around 50 C) for a 90-day period and were removed\\u000a at regular intervals

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

1985-01-01

114

Enzymatic synthesis of polyglycerol-fatty acid esters in a solvent-free system  

Microsoft Academic Search

The enzymatic transesterification of fatty acid methyl esters from vegetable oil and polyglycerol has been successfully performed\\u000a in the presence of Lipozyme without any solvent. The optimal conditions to obtain a mixture with lipophilic tensioactive properties\\u000a were found to be a molar ratio of fatty acid methyl esters and polyglycerol of 1.33:1 at 60C. Evaporation of the methanol\\u000a produced in

D. Charlemagne; M. D. Legoy

1995-01-01

115

Enantioselective synthesis of bis-?-amino acid esters via asymmetric phase-transfer catalysis  

Microsoft Academic Search

Application of N-anthracenylmethyl dihydrocinchonidinium bromide quaternary ammonium phase-transfer catalysts to the enantio- and diastereoselective synthesis of a series of bis-?-amino acid esters is reported. Under liquid-liquid phase-transfer conditions the target amino acid esters are obtained with high enantiomeric excess (?95%e.e.) via alkylation of two molecules of a benzophenone-derived glycine-imine with an appropriate dibromide.

Barry Lygo; John Crosby; Justine A. Peterson

1999-01-01

116

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

117

Analysis of the dark-colored impurities in sulfonated fatty acid methyl ester  

Microsoft Academic Search

A fractionally distilled C14?C16 fatty acid methyl ester, derived from palm oil, was sulfonated with gaseous SO3 in a falling film reactor to form an ?-sulfo fatty acid methyl ester (?-SF; unbleached and unneutralized form). The included\\u000a dark-colored impurities were then separated from ?-SF as a diethyl ether-insoluble matter. After purification by thin-layer\\u000a chromatography, the colored species were analyzed by

Kaoru Yamada; Shigeaki Matsutani

1996-01-01

118

The Use of Fatty Acid Esters to Enhance Free Acid Sophorolipid Synthesis  

Microsoft Academic Search

Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate,\\u000a Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid\\u000a sophorolipids (SLs). Fed-batch fermentations of Candida bombicola resulted in SL yields of 46 4 g\\/l, 42 7 g\\/l and 18 6 g\\/l from Me-Soy, Et-Soy, and Pro-Soy, respectively. Liquid chromatography

Richard D. Ashby; Daniel K. Y. Solaiman; Thomas A. Foglia

2006-01-01

119

Ammonolysis of esters of hydroxybenzoic acids on a boron phosphate catalyst  

SciTech Connect

In this investigation boron phosphate catalyst was used for ammonolysis of methyl and ethyl esters of salicylic and 4-hydroxybenzoic acids. It was shown that ammonolysis of methyl and ethyl esters of salicylic and 4-hydroxybenzoic acids in presence of boron phosphate catalyst at a ratio of 3-7 moles of ammonia per mole of ester in a contact time of 1-5 sec at 380-400/sub 0/ can be used for obtaining o- and p- hydroxybenzonitriles in yields of over 90% of the theoretical.

Suvorov, B.V.; Bukeikhanov, N.R.; Li, L.V.; Zulkasheva, A.Z.

1987-09-10

120

A novel route for synthesizing esters and polyesters from the Diels–Alder adduct of levopimaric acid and acrylic acid  

Microsoft Academic Search

A novel route for the esterification of the Diels–Alder adduct between abietic acid, in its isomer form of levopimaric acid, and acrylic acid was established. The high purity Diels–Alder adduct was prepared starting from rosin acids. When the adduct was subjected to a condensation reaction in the presence of a cyclic carbonate ester and of an efficient amine catalyst, hydroxyalkyl

Fanica Mustata; Ioan Bicu

2010-01-01

121

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

122

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. PMID:22623494

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

2012-01-01

123

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

124

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

125

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 Parkinson’s 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. PMID:20703328

Goldberg, Joel S.

2010-01-01

126

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

PubMed

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 Parkinson's 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. PMID:20703328

Goldberg, Joel S

2010-01-01

127

76 FR 7703 - 1,4-Benzenedicarboxylic Acid, Dimethyl Ester, Polymer With 1,4-Butanediol, Adipic Acid, and...  

Federal Register 2010, 2011, 2012, 2013

...EPA-HQ-OPP-2010-0838; FRL-8863-9] 1,4-Benzenedicarboxylic Acid, Dimethyl Ester, Polymer With 1,4- Butanediol, Adipic Acid, and Hexamethylene...requirement of a tolerance for residues of 1,4-benzenedicarboxylic acid, dimethyl...

2011-02-11

128

Improved preparation and structural investigation of 4-aryl-4-oxo-2-hydroxy-2-butenoic acids and methyl esters  

Microsoft Academic Search

A simple and efficient oxalylation of aryl methyl ketones was accomplished with dimethyl oxalate in the presence of sodium methoxide. The unpreviously reported sodium ketoenolate esters were isolated and gently hydrolyzed into the ketoenol esters in good yields. Alternatively the sodium ketoenolate esters hydrolysis could also be conducted to directly afford the ketoenol acids, which represent one of the most

Cédric Maurin; Fabrice Bailly; Philippe Cotelle

2004-01-01

129

Z .European Journal of Pharmacology 353 1998 2331 An entourage effect: inactive endogenous fatty acid glycerol esters  

E-print Network

acid glycerol esters enhance 2-arachidonoyl-glycerol cannabinoid activity Shimon Ben-Shabat a , Ester Abstract Z .2-Arachidonoyl-glycerol 2-Ara-Gl has been isolated from various tissues and identified and gut, 2-Ara-Gl is accompanied by several1 2 Z . Z .2-acyl-glycerol esters, two major ones being 2

Vogel, Zvi

130

Lewis acids catalysed Fries rearrangement of isopropylcresol esters  

Microsoft Academic Search

In the course of the Fries rearrangement, aluminium chloride frequently induces migration or elimination of alkyl groups. The results obtained with titanium tetrachloride for the synthesis of vicinalo-hydroxyketones are compared with those obtained with aluminium chloride for some aliphatic and aromatic esters of isopropylcresols. In order to understand the migration and elimination processes occurring, the stabilities of theo-hydroxyketones are studied

Robert Martin; Pierre Demerseman

1990-01-01

131

Paper chromatography of unsaturated fatty acid esters as their mercuric acetate addition compounds  

Microsoft Academic Search

Summary  A method is described by which unsaturated fatty acid esters can be separated and identified by reversed-phase paper chromatography.\\u000a The procedure is based upon the formation of the mercuric acetate addition compounds of the esters and the detection of the\\u000a compounds on the chromatograms, using the sensitive color reaction with diphenylcarbazone. The application of this technique\\u000a to the analysis of

Yoshiyuki Inouye; Manjiro Noda; Osamu Hirayama

1955-01-01

132

A conformational study of nucleic acid phosphate ester bonds using phosphorus-31 nuclear magnetic resonance.  

PubMed Central

A systematic phosphorus-31 nuclear magnetic resonance study of some nucleic acid constituents (6-N-(dimethyl)adenylyl-(3',5')-uridine and some nucleotide methyl esters) is presented. The temperature dependent phosphorus-31 chemical shifts were analyzed by standard thermodynamic procedures. It is shown that gt conformations about the P-O ester bonds have a lower free energy content relative to gg conformers. PMID:440971

Haasnoot, C A; Altona, C

1979-01-01

133

Myo-Inositol Esters of Indole-3-acetic Acid Are Endogenous Components of Zea mays L. Shoot Tissue 1  

PubMed Central

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-acetic 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. PMID:11540816

Chisnell, John R.

1984-01-01

134

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

Microsoft Academic Search

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

Nita Sahai

2004-01-01

135

The use of fatty acid esters to enhance free acid sophorolipid synthesis.  

PubMed

Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate, Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid sophorolipids (SLs). Fed-batch fermentations of Candida bombicola resulted in SL yields of 46 +/- 4 g/l, 42 +/- 7 g/l and 18 +/- 6 g/l from Me-Soy, Et-Soy, and Pro-Soy, respectively. Liquid chromatography with atmospheric pressure ionization mass spectrometry (LC/API-MS) showed that Me-Soy resulted in 71% open-chain SLs with 59% of those molecules remaining esterified at the carboxyl end of the fatty acids. Et-Soy and Pro-Soy resulted in 43% and 80% open-chain free-acid SLs, respectively (containing linoleic acid and oleic acid as the principal fatty acid species linked to the sophorose sugar at the omega-1 position), with no evidence of residual esterification. PMID:16555009

Ashby, Richard D; Solaiman, Daniel K Y; Foglia, Thomas A

2006-02-01

136

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

137

Inhibitory Effects of Caffeic Acid Phenethyl Ester Derivatives on Replication of Hepatitis C Virus  

PubMed Central

Caffeic acid phenethyl ester (CAPE) has been reported as a multifunctional compound. In this report, we tested the effect of CAPE and its derivatives on hepatitis C virus (HCV) replication in order to develop an effective anti-HCV compound. CAPE and CAPE derivatives exhibited anti-HCV activity against an HCV replicon cell line of genotype 1b with EC50 values in a range from 1.0 to 109.6 µM. Analyses of chemical structure and antiviral activity suggested that the length of the n-alkyl side chain and catechol moiety are responsible for the anti-HCV activity of these compounds. Caffeic acid n-octyl ester exhibited the highest anti-HCV activity among the tested derivatives with an EC50 value of 1.0 µM and an SI value of 63.1 by using the replicon cell line derived from genotype 1b strain Con1. Treatment with caffeic acid n-octyl ester inhibited HCV replication of genotype 2a at a similar level to that of genotype 1b irrespectively of interferon signaling. Caffeic acid n-octyl ester could synergistically enhance the anti-HCV activities of interferon-alpha 2b, daclatasvir, and VX-222, but neither telaprevir nor danoprevir. These results suggest that caffeic acid n-octyl ester is a potential candidate for novel anti-HCV chemotherapy drugs. PMID:24358168

Shen, Hui; Yamashita, Atsuya; Nakakoshi, Masamichi; Yokoe, Hiromasa; Sudo, Masashi; Kasai, Hirotake; Tanaka, Tomohisa; Fujimoto, Yuusuke; Ikeda, Masanori; Kato, Nobuyuki; Sakamoto, Naoya; Shindo, Hiroko; Maekawa, Shinya; Enomoto, Nobuyuki; Tsubuki, Masayoshi; Moriishi, Kohji

2013-01-01

138

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

139

Partitioning of homologous nicotinic acid ester prodrugs (nicotinates) into dipalmitoylphosphatidylcholine (DPPC) membrane bilayers  

Microsoft Academic Search

The partitioning behavior of a series of perhydrocarbon nicotinic acid esters (nicotinates) between aqueous solution and dipalmitoylphosphatidylcholine (DPPC) membrane bilayers is investigated as a function of increasing alkyl chain length. The hydrocarbon nicotinates represent putative prodrugs, derivatives of the polar drug nicotinic acid, whose functionalization provides the hydrophobic character necessary for pulmonary delivery in a hydrophobic, fluorocarbon solvent, such as

Vivian Ojogun; Sandhya M. Vyas; Hans-Joachim Lehmler; Barbara L. Knutson

2010-01-01

140

Structural analysis and antitussive evaluation of five novel esters of verticinone and bile acids.  

PubMed

Shedan-Chuanbei powder, a complex of traditional Chinese medicine preparation, which consists of Snake Bile (Chinese name "Shedan") and Fritillariae Cirrhosae (Chinese name "Chuanbei"), is the most popular antitussive and expectorant formulation in Chinese communities. However, the clinical application of Shedan-Chuanbei powder is now stringently limited because of the shortage of the two crude medicinal materials, especially for the sake of animal protection. In addition, the inherent defects of the most of the complex of traditional Chinese medicine such as the indistinct basal pharmacodynamic materials and the difficulties in quality control had blocked them heading into the international medicinal market. So we attempted to seek new substitute for Shedan-Chuanbei powder for antitussive drugs. In order to gain some new compounds with better bioactivity and attenuated toxicity, we tried to combine two kinds of drugs through ester bond. Enlightened with "combination principle" in drug discovery, we synthesized five novel esters of verticinone and bile acids, both of which are the major bioactive components in Shedan-Chuanbei powder. We then evaluated the antitussive activity and the acute toxicity of the five ester-linked compounds. The five ester-linked compounds had much more potent antitussive activity and expectorant activity than single bile acids at the same doses, and had equivalent antitussive activity and expectorant activity in comparison with about double moles dose of the monomer verticinone. Especially, cholic acid-verticinone ester had much more potent antitussive effects than the monomer verticinone or cholic acid at the same dose. A further acute toxicity study showed that the LD(50) values of the five ester-linked compounds exceeded 3.5g/kg by intraperitoneal injection in mice. Based on the studies of pharmacology and acute toxicity, the five ester-linked compounds have synergic pharmacodynamic action and attenuated toxicity compared with single verticinone and single bile acids. PMID:19154752

Zhang, Jiu-Liang; Wang, Hui; Pi, Hui-Fang; Ruan, Han-Li; Zhang, Peng; Wu, Ji-Zhou

2009-01-01

141

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, François W.; DeVries, Timothy; Matear, Richard

2014-01-01

142

Hydrolysis of fatty acid esters by Malassezia furfur: different utilization depending on alcohol moiety.  

PubMed

The lipophilic yeast Malassezia furfur belongs to the resident skin flora but has been implicated in various skin diseases. While topical oily preparations may support its growth, their formulation may be altered by yeast-dependent enzymatic degradation. Different synthetic fatty acid (mono-)esters used as refatting agents were mixed with 10(4), 10(5) and 5 x 10(5) yeasts/microliters, respectively, and incubated at 35 degrees C for a maximum of 48 h on selective agar for pathogenic fungi (Merck). The amount and pattern of generated free acids were evaluated by densitometric and gas chromatographic analysis, while yeast density was determined in a Neubauer chamber. Depending on the inoculum, yeast-dependent hydrolysis occurred immediately and was best effected in ethyl esters, followed by isopropyl esters, whereas hydrolysis of decyl oleate was only limited. Of the fatty acids released, unsaturated fatty acids were more stimulative to growth than saturated fatty acids; no toxic effects were observed. In conclusion, yeast-dependent hydrolysis of these synthetic fatty acid (mono-)esters was critically dependent on alcohol moiety, while growth promotion was best effected by unsaturated fatty acids. These results may help to improve the compatibility of topical formulations, especially in seborrheic areas. PMID:7604636

Mayser, P; Führer, D; Schmidt, R; Gründer, K

1995-03-01

143

Alternative fuel properties of tall oil fatty acid methyl ester-diesel fuel blends.  

PubMed

In this experimental work, tall oil methyl ester-diesel fuel blends as alternative fuels for diesel engines were studied. Tall oil methyl ester was produced by reacting tall oil fatty acids with methyl alcohol under optimum conditions. The blends of tall oil methyl ester-diesel fuel were tested in a direct injection diesel engine at full load condition. The effects of the new fuel blends on the engine performance and exhaust emission were tested. It was observed that the engine torque and power output with tall oil methyl ester-diesel fuel blends increased up to 6.1% and 5.9%, respectively. It was also seen that CO emissions decreased to 38.9% and NO(x) emissions increased up to 30% with the new fuel blends. The smoke opacity did not vary significantly. PMID:16524723

Altiparmak, Duran; Keskin, Ali; Koca, Atilla; Gürü, Metin

2007-01-01

144

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

PubMed

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 0.5g 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. PMID:22115087

Sharma, Prasesh; Kappler, Andreas

2011-11-01

145

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

146

Effect of iron in zinc silicate concentrate on leaching with sulphuric acid  

Microsoft Academic Search

It is shown that the iron content in zinc silicate concentrates with either high (8–11%) or low (3%) iron does not significantly affect the kinetics or overall recovery of zinc extraction in sulphuric acid. Most of the iron was present as hematite and franklinite with little iron contained in willemite. A small reduction in zinc recovery from 98.5% to 97.5%

A. D. Souza; P. S. Pina; F. M. F. Santos; C. A. da Silva; V. A. Leão

2009-01-01

147

Analysis of sulfoxylated methyl esters (?-MES): Sulfonic acid composition and isomer identification  

Microsoft Academic Search

Derivatization of a C12?-methyl ester sulfonic acid by using iodide-trifluoroacetic anhydride in dimethylformamide in a one-step reaction yielded\\u000a derivatized sulfonic thiotrifluoroacetates. The latter have been analyzed by gas chromatography-mass spectrometry (MS) and\\u000a liquid chromatography-MS techniques so that, for the first time, the acid composition and the mono sulfonic acid isomer distribution\\u000a are shown.

L. Cohen; F. Soto; M. S. Luna; C. R. Pratesi; G. Cassani; L. Faccetti

2003-01-01

148

The Optimization of Conversion of Waste Edible Oil to Fatty Acid Methyl Esters in Homogeneous Media  

Microsoft Academic Search

Conversion of waste edible oil to the fatty acid methyl esters was optimized using sulfuric acid as a catalyst for transesterification and esterification simultaneously, and adding tetrahydrofuran as a cosolvent for producing a homogeneous media. The optimized model was established by the response surface methodology. The optimum conditions were methanol\\/oil molar ratio of 21:1, 3.95% of sulphuric acid based on

L. Zhang; Q. Jin; K. Zhang; J. Huang; X. Wang

2012-01-01

149

A study of the alumina-silica 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.  

PubMed

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 specific surface area of the Si adsorbent was small and it's adsorption capacity of silicic acid was low. Although the specific surface area of the Al adsorbent was also small, it was significantly increased by the adsorption of silicic acid and it's adsorption capacity was high. Based on the change in the local structure of aluminum ion by the adsorption of silicic acid, the Al adsorbent was considered to be silica particles covered with crystalline aluminum hydroxide. Moreover, it was concluded that the increase in the specific surface area of the Al adsorbent and the decrease in the zeta potential were due to the formation of an amorphous aluminosilicate with a large surface area and a negative charge (one 4-coordinated Al) by the reaction between aluminum ions and silicic acids. PMID:16290755

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

2002-08-01

150

Molecular Basis of Prodrug Activation by Human Valacyclovirase, an [alpha]-Amino Acid Ester Hydrolase  

SciTech Connect

Chemical modification to improve biopharmaceutical properties, especially oral absorption and bioavailability, is a common strategy employed by pharmaceutical chemists. The approach often employs a simple structural modification and utilizes ubiquitous endogenous esterases as activation enzymes, although such enzymes are often unidentified. This report describes the crystal structure and specificity of a novel activating enzyme for valacyclovir and valganciclovir. Our structural insights show that human valacyclovirase has a unique binding mode and specificity for amino acid esters. Biochemical data demonstrate that the enzyme hydrolyzes esters of {alpha}-amino acids exclusively and displays a broad specificity spectrum for the aminoacyl moiety similar to tricorn-interacting aminopeptidase F1. Crystal structures of the enzyme, two mechanistic mutants, and a complex with a product analogue, when combined with biochemical analysis, reveal the key determinants for substrate recognition; that is, a flexible and mostly hydrophobic acyl pocket, a localized negative electrostatic potential, a large open leaving group-accommodating groove, and a pivotal acidic residue, Asp-123, after the nucleophile Ser-122. This is the first time that a residue immediately after the nucleophile has been found to have its side chain directed into the substrate binding pocket and play an essential role in substrate discrimination in serine hydrolases. These results as well as a phylogenetic analysis establish that the enzyme functions as a specific {alpha}-amino acid ester hydrolase. Valacyclovirase is a valuable target for amino acid ester prodrug-based oral drug delivery enhancement strategies.

Lai, Longsheng; Xu, Zhaohui; Zhou, Jiahai; Lee, Kyung-Dall; Amidon, Gordon L. (Michigan)

2008-07-08

151

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

Federal Register 2010, 2011, 2012, 2013

...concerning the Notice of Filing (NOF) for Pesticide Petition (PP) 0E7699 for polymerized fatty acid esters with aminoalcohol alkoxylates...Correction Do? The Notice of Filing (NOF) for Pesticide Petition (PP) 0E7699 for polymerized fatty acid esters with aminoalcohol...

2010-11-17

152

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

153

Paper chromatography of phospholipides on silicic acid impregnated glass fiber filter paper  

Microsoft Academic Search

Summary  1. A reasonably reproducible method has been developed for separating lysolecithin, lecithin,, sphingomyelin, and phosphatidylethanolamine,\\u000a using glass fiber filter paper impregnated with silicic acid as the chromatographic medium and 1:1 methanol:ethyl ether as\\u000a the developing solvent.\\u000a \\u000a 2. Hot sulfuric acid was used to locate the chromatographed compounds on the chromatogram. The advantages and disadvantages\\u000a of this reagent and the other

Julius W. Dieckert; Raymond Reiser

1956-01-01

154

Fatty acid esters of monochloropropanediol (MCPD) and glycidol in refined edible oils.  

PubMed

Recently, fatty acid esters of monochloropropanediol (MCPD) and that of glycidol have been reported in refined edible oils. Since then a wealth of research has been published on the factors influencing the formation of these contaminants in foods. It can be noted that the predominant precursors in a given matrix will not necessarily be the same as in other matrices. Further, proven relationships in the past between precursors responsible for free MCPD or free glycidol formation will not necessarily be valid for their fatty acid-esterified counterparts. This review attempts to summarise the current status of the literature as it pertains to the reasons surrounding the manifestation of MCPD esters and glycidyl esters in oils and fats. Recent efforts to mitigate the levels of these contaminants were highlighted and put into the context of their respective reaction matrices. As more accurate occurrence data for MCPD esters and glycidyl esters in other foods are collected, more targeted mitigation experiments can be formulated with respect to the reaction matrices under investigation. PMID:23020600

Craft, B D; Chiodini, A; Garst, J; Granvogl, M

2013-01-01

155

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...

156

SEPARATION OF T-MAZ ETHOXYLATED SORBITAN FATTY ACID ESTERS BY REVERSE PHASE CHROMATOGRAPHY  

EPA Science Inventory

The method for determination of T-MAZ ethoxylated sorbitan fatty acid esters is described. This work demonstrates that with a less retentive C8 alkyl bonded phase packing, reverse phase chromatography can be used to analyze nonionic polymer mixtures with a molecular weight range ...

157

Preferential cytotoxicity on tumor cells by caffeic acid phenethyl ester isolated from propolis  

Microsoft Academic Search

Summary The honeybee hive product, propolis, is a folk medicine employed for treating various ailments. Many important pharmaceutical properties have been ascribed to propolis, including anti-inflammatory, antiviral, immunostimulatory and carcinostatic activities. Propolis extracts have provided an active component identified as caffeic acid phenethyl ester (CAPE), which was readily prepared in one step. Differential cytotoxicity has been observed in normal rat\\/human

D. Grunberger; R. Banerjee; K. Eisinger; E. M. Oltz; L. Efros; M. Caldwell; V. Estevez; K. Nakanishi

1988-01-01

158

Functionally Substituted Amides and Esters of 3,4,4-Trichloro-3-butenoic Acid  

Microsoft Academic Search

Substituted amides and esters of 3,4,4-trichloro-3-butenoic acid were prepared by reactions of its chloride with appropriate amines and alcohols. Treatment of 3,4,4-trichloro-3-butenomorpholide and tert-butyl 3,4,4-trichloro-3-butenoate results in nucleophilic substitution of the internal chlorine atom with the morpholine residue, accompanied by prototropic allyl rearrangement.

S. K. Petkevich; E. A. Dikusar; V. I. Potkin; R. V. Kaberdin; K. L. Moiseichuk; A. P. Yuvchenko; P. V. Kurman

2004-01-01

159

Combustion characteristics of fatty acid methyl esters derived from recycled cooking oil  

Microsoft Academic Search

The goal of this study is to find out the exhaust emissions differences produced by different kinds of fatty acid methyl esters (FAME) derived from used cooking oils and animal fats, as well as the importance of the purification step in exhaust emissions production. A total of 120L of waste vegetable oil and 30L of waste frying oil were collected

Yo-ping Greg Wu; Ya-fen Lin; Chang-Tang Chang

2007-01-01

160

ESTIMATION OF PHOSPHATE ESTER HYDROLYSIS RATE CONSTANTS. II. ACID AND GENERAL BASE CATALYZED HYDROLYSIS  

EPA Science Inventory

SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate acid and neutral hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition states of a ...

161

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

Microsoft Academic Search

Summary  Disodium 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

162

Lowered ?3 polyunsaturated fatty acids in serum phospholipids and cholesteryl esters of depressed patients  

Microsoft Academic Search

Depression is associated with a lowered degree of esterification of serum cholesterol, an increased C20:4?6\\/C20:5?3 ratio and decreases in ?3 fractions in fatty acids (FAs) or in the red blood cell membrane. The aims of the present study were to examine: (i) serum phospholipid and cholesteryl ester compositions of individual saturated fatty acids (SFAs), monounsaturated FAs (MUFAs) and polyunsaturated FAs

Michael Maes; Armand Christophe; Joris Delanghe; Carlo Altamura; Hugo Neels; Herbert Y Meltzer

1999-01-01

163

Synthesis of functional poly(ester-andydride)s based on succinic acid  

Microsoft Academic Search

This paper describes the three-step synthesis and characteristics of succinic acid based functional poly(ester-anhydride)s bearing allyl groups in side chains. Firstly, carboxyl terminated functional oligoesters with molecular weight in the range of 300–1000 were obtained by melt condensation of allyl glycidyl ether with an excess of succinic acid. Secondly, carboxyl end groups of the macromer obtained were converted to mixed

Katarzyna Jaszcz; Jan ?ukaszczyk; Monika ?miga-Matuszowicz

2008-01-01

164

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

165

SYNTHESIS AND STRUCTURE OF THE COMPLEXES OF ESTERS OF SOME PHOSPHONIC ACIDS AND AMIDES WITH MOLYBDENUM DIOXODICHLORIDE  

Microsoft Academic Search

The complexes L?MoO2Cl2 (2), L?·MoO2Cl2 (4), L??·MoO2Cl2 (6) and L????MoO2Cl2 (8) were obtained by the reaction of MoO2Cl2 and the ligands: L=diethyl ester of 2-dimethylamino-2-oxoethylphosphonic acid (1), L?=diethyl ester of 2-amino-2-oxoethylphosphonic acid (3), L??=tetraethyl ester of methylenediphosphonic acid (5) and L???=tetraethylester of ethylenediphosphonic acid (7). They were characterized by elemental analyses, IR and NMR spectroscopy. The crystal structure of the

E. T. K. Haupt; J. Kopf; J. Petrova; S. Momchilova

2002-01-01

166

Synthesis of fatty acid esters by recombinant Staphylococcus epidermidis lipases in aqueous environment.  

PubMed

Various flavor esters were obtained by using recombinant lipases from Staphylococcus epidermidis as a catalyst in an aqueous environment. These esters were enzymatically synthesized to overcome the problems associated with chemical processes. This study showed that the S. epidermidis lipases could catalyze ester synthesis from decyl alcohol and fatty acids of different chain length. The wild-type and mutant lipases (M419A and V649I) could efficiently catalyze the synthesis of decyl alcohol esters of unsaturated fatty acids. In contrast, the yield of decyl laurate was better by wild-type and mutant enzyme V6491, but mutant enzyme M419A only favored the synthesis of decyl myristate. The esterification of oleic acid and various carbon-chain-length alcohols from ethanol to hexadecanol increased up to decanol by wild-type and M419A mutant enzymes and reached an optimum for dodecanol by V6491 mutant enzyme. The enzyme is potentially useful in food industries such as dairy product flavoring. PMID:11368644

Chang, R C; Chou, S J; Shaw, J F

2001-05-01

167

40 CFR 721.2140 - Carbo-poly-cycli-col azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt.  

Code of Federal Regulations, 2012 CFR

...azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt. 721.2140 Section 721...azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt. (a) Chemical substance...azo-al-kyl-a-mino-al-kyl-car-bo-mon-o-cyc-lic ester, halogen acid salt (PMN P-88-1682) is subject...q). (iii) Release to water. Requirements as...

2012-07-01

168

40 CFR 721.2140 - Carbo-poly-cycli-col azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt.  

Code of Federal Regulations, 2013 CFR

...azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt. 721.2140 Section 721...azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt. (a) Chemical substance...azo-al-kyl-a-mino-al-kyl-car-bo-mon-o-cyc-lic ester, halogen acid salt (PMN P-88-1682) is subject...q). (iii) Release to water. Requirements as...

2013-07-01

169

40 CFR 721.2140 - Carbo-poly-cycli-col azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt.  

Code of Federal Regulations, 2011 CFR

...azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt. 721.2140 Section 721...azo-alkyl-aminoalkyl-carbo-mono-cyclic ester, halogen acid salt. (a) Chemical substance...azo-al-kyl-a-mino-al-kyl-car-bo-mon-o-cyc-lic ester, halogen acid salt (PMN P-88-1682) is subject...q). (iii) Release to water. Requirements as...

2011-07-01

170

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

171

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

172

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

173

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

174

40 CFR 721.5375 - Ni-tro-thio-phene-car-boxy-lic acid, ethyl es-ter, bis-[[[[(sub-sti-tut-ed)] amino]-alkyl-phenyl...  

...2014-07-01 false Ni-tro-thio-phene-car-boxy-lic acid, ethyl es-ter, bis...721.5375 Ni-tro-thio-phene-car-boxy-lic acid, ethyl es-ter, bis...chemical substance ni-tro-thio-phene-car-boxy-lic acid, ethyl ester,...

2014-07-01

175

Enzymatic esterification of tapioca maltodextrin fatty acid ester.  

PubMed

In this work new types of hydrophobically modified maltodextrin were prepared by enzyme-catalyzed reaction of maltodextrin and three fatty acids: decanoic acid (C-10), lauric acid (C-12) and palmitic acid (C-16). Lipase obtained from Thermomyces lanuginosus was found to be a useful biocatalyst in the maltodextrin esterification. Esterified maltodextrin with a degree of substitution (DS) 0.015-0.084 was prepared at the optimum conditions of 60 °C for 4 h. The DS was found to be at its highest when maltodextrin and fatty acids were taken in the ratio 1:0.5. The functional properties of these esterified maltodextrin were investigated. All esterified maltodextrin did not completely dissolve in water. Esterified maltodextrin at a concentration of 25% (w/w) exhibited Newtonian flow behavior similar to that of native maltodextrin. Esterified maltodextrin had a higher viscosity compare to native maltodextrin. X-ray diffraction pattern of esterified maltodextrin indicated crystallization of the fatty acid side chains. The thermal stability of esterified maltodextrin was checked by differential scanning calorimetry (DSC). Esterified maltodextrin was then used as an emulsifier to make n-hexadecane O/W emulsions. The emulsions were characterized according to their oil droplet characteristics and emulsification index. PMID:24274521

Udomrati, Sunsanee; Gohtani, Shoichi

2014-01-01

176

Hydroxycinnamic acid ethyl esters as precursors to ethylphenols in wine.  

PubMed

A method for determining ethyl coumarate and ethyl ferulate in wine using GC-MS with deuterium-labeled analogues has been developed and used to measure the evolution of these two esters during the production of two commercial monovarietal red wines, cv. Grenache and Shiraz. During fermentation, the concentration of ethyl coumarate rose from low levels to 0.4 mg/L in Grenache and 1.6 mg/L in Shiraz wines. These concentrations then increased further during barrel aging to 1.4 and 3.6 mg/L, respectively. The concentration of ethyl ferulate was much lower, reaching a maximum of only 0.09 mg/L. Conversion of ethyl coumarate and ethyl ferulate to their corresponding ethylphenols was observed during fermentations of a synthetic medium with two strains of Dekkera bruxellensis (AWRI 1499 and AWRI 1608), while a third (strain AWRI 1613) produced no ethylphenols at all from these precursors. Strains AWRI 1499 and 1608 produced 4-ethylphenol from ethyl coumarate in 68% and 57% yields, respectively. The corresponding yields of 4-ethylguaiacol from ethyl ferulate were much lower, 7% and 3%. Monitoring of ethyl coumarate and ethyl ferulate concentration during the Dekkera fermentations showed that the selectivity for ethylphenol production according to yeast strain and the precursor was principally a result of variation in esterase activity. Consequently, ethyl coumarate can be considered to be a significant precursor to 4-ethylphenol in wines affected by these two strains of Brettanomyces/Dekkera yeast, while ethyl ferulate is not an important precursor to 4-ethylguaiacol. PMID:22324721

Hixson, Josh L; Sleep, Nicola R; Capone, Dimitra L; Elsey, Gordon M; Curtin, Christopher D; Sefton, Mark A; Taylor, Dennis K

2012-03-01

177

Synthesis of sugar fatty acid esters using a ?-xylosidase from Aspergillus awamori for transxylosylation.  

PubMed

Aspergillus awamori K4 ?-xylosidase has broad acceptor specificity. It has been used to synthesize a sugar fatty acid ester via its transxylosylation activity. One xylosyl residue was initially transferred to hexamethylene glycol as a linker with a yield of 0.36 g/g xylobiose. Linoleic acid was subsequently linked to one terminal hydroxyl side of the transfer product hydroxyhexyl xyloside through an esterification reaction catalyzed by a lipase. The synthesis of hexyl linoleoyl xyloside was confirmed by TOF-MS analysis. The binding with a linker improved the esterification reaction because of the hydrophobic hexamethylene chain and also prevented steric hindrance by the xylosyl residue. This sugar fatty acid ester synthesis method using transglycosylation should facilitate the production of emulsifiers or surfactants with various functions. PMID:21805184

Kurakake, Masahiro; Ito, Yosuke; Komaki, Toshiaki

2011-12-01

178

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

SciTech Connect

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 parent. Water CI provides for an approximately 200:1 selectivity of carbonyl species over alkanes. No reagent ions are detected above 55 amu, allowing species as small as acetone, propanal, acetic acid, and methyl formate to be identified. When deuterate water was used as the reagent, only the carboxylic acids and ..beta..-diketones showed significant H/D exchange. The use of water CI to identify carbonyl compounds in a wastewater from the supercritical water extraction of lignite coal, in lemon oil, and in whiskey volatiles is discussed.

Hawthorne, S.B.; Miller, D.J.

1986-11-01

179

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

180

Functional Heterogeneity of Single Pancreatic ?-Cells Stimulated by L-Leucine and the Methyl Ester of Succinic or Glutamic Acid  

Microsoft Academic Search

Single pancreatic ?-cells exposed to D-glucose in the absence or presence of L-leucine and to the amino acid in the absence or presence of either the monomethyl ester of succinic acid (SME) or the dimethyl ester of glutamic acid (SME) were examined in a reverse hemolytic plaque assay for insulin release. At a D-glucose concentration of 11.1 mM, plaque-forming cells

M. Hiriart; M. C. Sanchezsoto; M. C. Ramirezmedeles; W. J. Malaisse

1995-01-01

181

Molecular and enzymatic analyses of lysosomal acid lipase in cholesteryl ester storage disease.  

PubMed

Human lysosomal acid lipase (hLAL) is essential for the hydrolysis of cholesteryl esters and triglycerides in the lysosome. Defective hLAL activity leads to two autosomal recessive traits, Wolman disease (WD) or cholesteryl ester storage disease (CESD). Phenotypically, WD has accumulation of both triglycerides and cholesteryl esters, while CESD has mainly elevated cholesteryl esters. We characterized mutations in the hLAL gene from two CESD siblings. By reverse transcriptase-PCR (RT-PCR) and cDNA cloning and sequencing, we identified homozygous deletion mutations of nucleotides 863 to 934, in the hLAL transcript. Normal levels of LAL mRNA were detected. The deletion in mRNA is due to a G to A transition in the last nucleotide of exon 8 of the hLAL gene, a splice junction mutation (E8SJM) that resulted in exon skipping, and a predicted in-frame deletion of the 24 amino acids. [35S]Met metabolic labeling studies in fibroblasts showed a low level of E8SJM LAL ( approximately 38%) that was highly unstable. Heterologous expression of E8SJM LAL in insect cells gave an LAL with low catalytic activity toward cholesteryl oleate and triolein. The effects of this mutation are complex with the production of decreased amounts of an unstable LAL that is catalytically defective. The results suggest that E8SJM leads to essentially a null allele and that the differences in WD and CESD phenotype involve other factors. PMID:9705237

Du, H; Sheriff, S; Bezerra, J; Leonova, T; Grabowski, G A

1998-06-01

182

ORIGINAL ARTICLE -Aminolevulinic acid and its methyl ester induce  

E-print Network

IX (PpIX), serving as photosensi- tizer in photodynamic therapy (PDT). While PDT is highly effective take up ALA and MAL and synthesize PpIX from both, enabling a direct impact of photodynamic therapy . Methyl- aminolevulinic acid . Photodynamic therapy. Cellular uptake . Protoporphyrin IX . GABA

Lübbert, Hermann

183

Enantio- and chemoselective Brønsted-acid/Mg(nBu)2 catalysed reduction of ?-keto esters with catecholborane.  

PubMed

The first enantio- and chemoselective Brønsted-acid catalysed reduction of ?-keto esters with catecholborane has been developed. The ?-hydroxy esters were obtained under mild reaction conditions in virtually quantitative yields and excellent enantioselectivities. With slight modifications both enantiomers can be obtained without any loss of selectivity. PMID:24643455

Enders, Dieter; Stöckel, Bianca A; Rembiak, Andreas

2014-05-01

184

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 26–27 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

185

In vitro induction of micronuclei by monofunctional methanesulphonic acid esters  

Microsoft Academic Search

Six monofunctional alkylating methanesulphonates of widely varying structures were investigated in the in vitro micronucleus assay with Syrian hamster embryo fibroblast cells. The results were compared with the alkylating activities measured in the 4-(nitrobenzyl)pyridine test (NBP-test) and the N-methyl mercaptoimidazole (MMI-test) as measures for SN2 reactivity as well as in the triflouoroacetic acid (TFA) solvolysis and the hydrolysis reaction as

Erwin Eder; Wolfgang Kütt; Christoph Deininger

2006-01-01

186

Fatty Acid Esters of Phloridzin Induce Apoptosis of Human Liver Cancer Cells through Altered Gene Expression  

PubMed Central

Phloridzin (phlorizin or phloretin 2?-O-glucoside) is known for blocking intestinal glucose absorption. We have investigated the anticarcinogenic effect of phloridzin and its novel derivatives using human cancer cell lines. We have synthesised novel acylated derivatives of phloridzin with six different long chain fatty acids by regioselective enzymatic acylation using Candida Antarctica lipase B. The antiproliferative effects of the new compounds were investigated in comparison with the parent compounds, phloridzin, aglycone phloretin, the six free fatty acids and chemotherapeutic drugs (sorafenib, doxorubicin and daunorubicin) using human hepatocellular carcinoma HepG2 cells, human breast adenocarcinoma MDA-MB-231 cells and acute monocytic leukemia THP-1 cells along with normal human and rat hepatocytes. The fatty acid esters of phloridzin inhibited significantly the growth of the two carcinoma and leukemia cells while similar treatment doses were not toxic to normal human or rat hepatocytes. The antiproliferative potency of fatty esters of phloridzin was comparable to the potency of the chemotherapeutic drugs. The fatty acid esters of phloridzin inhibited DNA topoisomerases II? activity that might induce G0/G1 phase arrest, induced apoptosis via activation of caspase-3, and decreased ATP level and mitochondrial membrane potential in HepG2 cells. Based on the high selectivity on cancer cells, decosahexaenoic acid (DHA) ester of phloridzin was selected for gene expression analysis using RT2PCR human cancer drug target array. Antiproliferative effect of DHA ester of phloridzin could be related to the down regulation of anti-apoptotic gene (BCL2), growth factor receptors (EBFR family, IGF1R/IGF2, PDGFR) and its downstream signalling partners (PI3k/AKT/mTOR, Ras/Raf/MAPK), cell cycle machinery (CDKs, TERT, TOP2A, TOP2B) as well as epigenetics regulators (HDACs). These results suggest that fatty esters of phloridzin have potential chemotherapeutic effects mediated through the attenuated expression of several key proteins involved in cell cycle regulation, DNA topoisomerases II? activity and epigenetic mechanisms followed by cell cycle arrest and apoptosis. PMID:25229655

Nair, Sandhya V. G.; Ziaullah; Rupasinghe, H. P. Vasantha

2014-01-01

187

Alcohol to Ester 21 ALCOHOL TO ESTER  

E-print Network

Alcohol to Ester 21 ALCOHOL TO ESTER Acid-Catalyzed Esterification of an Unknown Alcohol Summary: You will be given an unknown alcohol, you will convert it to an ester, and you will identify both the original alcohol and the derived ester using boiling point and H-NMR. Some Learning Goals: 1. Observe

Jasperse, Craig P.

188

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

189

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

190

Decarboxylative Allylation of Amino Alkanoic Acids and Esters via Dual Catalysis.  

PubMed

A combination of photoredox and palladium catalysis has been employed to facilitate the room temperature decarboxylative allylation of recalcitrant ?-amino and phenylacetic allyl esters. This operationally simple process produces CO2 as the only byproduct and provides direct access to allylated alkanes. After photochemical oxidation, the carboxylate undergoes radical decarboxylation to site-specifically generate radical intermediates which undergo allylation. A radical dual catalysis mechanism is proposed. Free phenylacetic acids were also allylated utilizing similar reactions conditions. PMID:25228064

Lang, Simon B; O'Nele, Kathryn M; Tunge, Jon A

2014-10-01

191

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

192

Saturation vapor pressures and vaporization enthalpies of esters of ethylene glycol and lower carboxylic acids  

NASA Astrophysics Data System (ADS)

Saturation vapor pressures and vaporization enthalpies of ethylene glycol and C1-C5 carboxylic acid disubstituted esters of normal and branched structures are determined by the transfer method in the temperature range of 295 to 327 K. Dependences of vaporization enthalpies versus the number of carbon atoms in a molecule and the retention indices are determined. An analysis of existing calculation schemes is given to help predict the vaporization enthalpy of the compounds under study.

Maslakova, A. S.; Krasnykh, E. L.; Levanova, S. V.

2011-10-01

193

Enzymatic synthesis of arbutin undecylenic acid ester and its inhibitory effect on mushroom tyrosinase  

Microsoft Academic Search

A novel tyrosinase inhibitor, an arbutin derivative having undecylenic acid at the 6-position of its glucose moiety, was enzymatically\\u000a synthesized. Its inhibitory activity was studied in vitro by using catechol and phenol as substrates. The IC50 value of the arbutin ester on tyrosinase using catechol (4 × 10?4 M) was 1% of that when arbutin (4 × 10?2 M) was used. Using phenol, IC50 of the

Y. Tokiwa; M. Kitagawa; T. Raku

2007-01-01

194

Phthalic acid esters found in municipal organic waste: enhanced anaerobic degradation under hyper-thermophilic conditions  

Microsoft Academic Search

Abstract Contamination of the organic fraction of municipal solid waste (OFMSW) with xenobiotic compounds,and their fate during anaerobic digestion was investigated. The phthalic acid ester di-(2- ethylhexyl)phthalate (DEHP) was identified as the main contaminant in OFMSW in concentrations more,than half of the threshold value for the use as fertilizer on agricultural soil in Denmark. Analysis of DEHP in samples before

H. hartmann; B. k. Ahring

195

Caffeic acid phenethyl ester protects against tamoxifen-induced hepatotoxicity in rats  

Microsoft Academic Search

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 (45mg\\/kg\\/day, i.p., for 10

Ashwag A. Albukhari; Hana M. Gashlan; Hesham A. El-Beshbishy; Ayman A. Nagy; Ashraf B. Abdel-Naim

2009-01-01

196

Micelle dyeing with low liquor ratio for reactive dyes using dialkyl maleic acid ester surfactants  

Microsoft Academic Search

Micelle dyeing with low liquor ratio is novel fabric dyeing method for cleaner production. Preparation and interaction of dye-surfactant micelles using dibutyl maleic acid ester sodium sulfate surfactant were investigated by UV–Vis spectra. Dyeing properties of cellulose fabrics using micelle dyeing with low liquor ratio were discussed by color yields (K\\/S), color differences (?E), exhaustion (E), fixation (F) and reactivity

Kongliang Xie; Fangfang Cheng; Weiguo Zhao; Lei Xu

2011-01-01

197

Biodegradation of phthalic acid esters (PAEs) in soil bioaugmented with acclimated activated sludge  

Microsoft Academic Search

The degradation characteristics of four phthalic acid esters (PAEs), i.e. di-methyl phthalate (DMP), di-ethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di-n-octyl phthalate (DOP) in the soil augmented with acclimated sludge was investigated in order to assess the efficacy of bioaugmentation as a strategy for remediating PAEs-contaminated soil and correlate the degradation rate of PAEs with their alkyl chain length. The

Wang Jianlong; Zhao Xuan; Wu Weizhong

2004-01-01

198

Estimation of heat of combustion of triglycerides and fatty acid methyl esters  

Microsoft Academic Search

Equations were developed for the estimation of gross heat of combustion (HG) of triglycerides (TGs) and fatty acid methyl\\u000a esters (FAMEs) from their saponification number (SN) and iodine value (IV). HG of TG=1,896,000\\/SN ? 0.6 IV — 1600 and HG of\\u000a FAME=618,000\\/SN ? 0.08 IV — 430. When these equations were tested on cottonseed oil, soybean oil, partially hydrogenated soybean

Kanit Krisnangkura

1991-01-01

199

Evaluation of eye irritation by S-(-)-10,11-dihydroxyfarnesic acid methyl ester secreted by Beauveria bassiana CS1029  

PubMed Central

The aim of this study was to investigate whether S-(-)-10,11-dihydroxyfarnesic acid methyl ester produced by cell subtype Beauveria bassiana CS1029 causes acute toxicity when used for cosmetic purposes by performing an eye irritation test. New Zealand white (NZW) rabbits were treated with a 100 mg/dose of S-(-)-10,11-dihydroxyfarnesic acid methyl ester according to standard procedure guidelines. No significant changes in terms of ocular lesions of the cornea, turbidity of the cornea, swelling of the eyelid or ocular discharge were observed in the methyl ester-treated groups, while sodium dioctyl sulfosuccinate, a positive control, caused severe toxicity. The anatomical and pathological observations indicate that the methyl ester produced by Beauveria bassiana CS1029 did not induce eye irritation in the lenses of the rabbits. The data suggest that the methyl ester evaluated in this study has promising potential as a cosmetic ingredient that does not irritate the eye. PMID:24137288

SON, HYEONG-U; LEE, SANG-HAN

2013-01-01

200

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

201

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

202

Isolation and Characterization of Esters of Indole-3-Acetic Acid from the Liquid Endosperm of the Horse Chestnut (Aesculus species) 1  

PubMed Central

Esters of indole-3-acetic acid were extracted and purified from the liquid endosperm of immature fruits of various species of the horse chestnut (Aesculus parviflora, A. baumanni, A.pavia rubra, and A. pavia humulis). The liquid endosperm contained, at least 12 chromatographically distinct esters. One of these compounds was purified and characterized as an ester of indole-3-acetic acid and myo-inositol. A second compound was found to be an ester of indole-3-acetic acid and the disaccharide rutinose (glucosyl-rhamnose). A third compound was partially characterized as an ester of indole-3-acetic acid and a desoxyaminohexose. PMID:11539676

Domagalski, Wojciech; Schulze, Aga; Bandurski, Robert S.

1987-01-01

203

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

204

Enantioselective bacterial hydrolysis of amido esters and diamides derived from (±)-trans-cyclopropane-1,2-dicarboxylic acid.  

PubMed

Different optically active amido esters, mixed acid esters, amido acids, and diamides derived from trans-cyclopropane-1,2-dicarboxylic acid were prepared from the commercially available diethyl (±)-trans-cyclopropane-1,2-dicarboxylate. The key step was the Rhodococcus rhodochrous IFO 15564 catalyzed hydrolysis of the corresponding racemic amide. The amidase present in this microorganism showed moderate to high enantioselectivity towards these substrates. In addition a simple and efficient Curtius rearrangement of some of the enzymatically prepared cyclopropanecarboxylic acids allowed us to obtain optically active ?-aminocyclopropanecarboxylic acid derivatives with high yields and enantiomeric excesses. PMID:24292844

Hugentobler, Katharina G; Rebolledo, Francisca

2014-01-28

205

Electrochemical behaviour of new dimeric esters and amides derived from caffeic acid in dimethylsulfoxide.  

PubMed

The electrochemical oxidation in DMSO of four new derivatives of caffeic acid (CA), two dimeric amides and two dimeric esters, is reported in this article. Although all of them contain two caffeoyl electroactive moieties in their structures, small differences in the connectors result in interesting changes in the electrochemical behaviour of this type of compound. Voltammograms of both esters do not show appreciable differences between them; however, an electrografting process occurs during the electrochemical oxidation of one of them, which suggests that the identity of the connector has an influence on the ability of the diesters to interact with the electrode surface. On the other hand, voltammograms of dimeric amides were more complex than those corresponding to dimeric esters. Electronic effects of diamine connectors seem to be related to the fact that caffeoyl moieties suffer from separate oxidation processes in both compounds. In contrast to their ferulic acid (FA) analogues, which have been studied by our group before, CA dimeric amides do not interact in an appreciable way with the electrode surface. In addition, a relationship between the oxidation potential and the inhibition percentage of the DPPH (2,2'-diphenyl-1-picrylhydrazyl) radical was not observed for the symmetrical CA derivatives studied here. However, the molecular flexibility seems to play a very important role in the Free Radical Scavenging Activity (FRSA) of this type of compound. PMID:24988384

Sánchez, Analilia; Martínez-Mora, Omar; Martínez-Benavidez, Evelin; Hernández, Javier; Domínguez, Zaira; Salas-Reyes, Magali

2014-08-21

206

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

207

Biodegradable Coumaric Acid-based Poly(anhydride-ester) Synthesis and Subsequent Controlled Release  

PubMed Central

p-Coumaric acid (pCA), a naturally occurring bioactive, has been chemically incorporated into a poly(anhydride-ester) backbone through solution polymerization following a Knoevenagel synthetic approach to overcome drug delivery issues associated with its short half-life in vivo. Nuclear magnetic resonance and Fourier transform infrared spectroscopies indicated that pCA was successfully incorporated without noticeable alterations in structural integrity. The weight-average molecular weight and thermal properties were determined for the polymer, which exhibited a molecular weight of over 26,000 Da and a glass transition temperature of 57 °C. In addition, in vitro pCA release via hydrolytic anhydride and ester bond cleavage demonstrated pCA release over 30 days and maintained its antioxidant activity, demonstrating its potential as a controlled release system. PMID:23836606

Ouimet, Michelle A.; Stebbins, Nicholas D.; Uhrich, Kathryn E.

2013-01-01

208

Organogels from dimeric bile acid esters: in situ formation of gold nanoparticles.  

PubMed

A new class of steroid dimers (bile acid derivatives) linked through ester functionalities were synthesized, which gelled various aromatic solvents. The organogels formed by the three dimeric ester molecules showed birefringent textures and fibrous nature by polarizing optical microscopy and scanning electron microscopy, respectively. A detailed rheological study was performed to estimate the mechanical strengths of two sets of organogels. In these systems, the storage modulus varied in the range of 0.8-3.5 × 10(4) at 1% w/v of the organogelators. The exponents of scaling of the storage modulus and yield stress of the two systems agreed well with those expected for viscoelastic soft colloidal gels with fibrillar flocs. The nanofibers in the organogel were utilized to engineer gold nanoparticles of different sizes and shapes and generate new gel-nanoparticle hybrid materials. PMID:23751127

Chakrabarty, Arkajyoti; Maitra, Uday

2013-07-01

209

Optimization of extraction of high-ester pectin from passion fruit peel (Passiflora edulis flavicarpa) with citric acid by using  

E-print Network

Optimization of extraction of high-ester pectin from passion fruit peel (Passiflora edulis flavicarpa) with citric acid by using response surface methodology Eloi´sa Rovaris Pinheiro a , Iolanda M to optimize the extraction of pectin with citric acid. The independent variables were citric acid

Ferreira, Márcia M. C.

210

Catalytic, Enantioselective Alkylation of r-Imino Esters: The Synthesis of Nonnatural r-Amino Acid Derivatives  

E-print Network

Catalytic, Enantioselective Alkylation of r-Imino Esters: The Synthesis of Nonnatural r-Amino Acid, 2001 Abstract: Methodology for the practical synthesis of nonnatural amino acids has been developed (up to 25:1/anti:syn), are protected nonnatural amino acids that represent potential precursors

Lectka, Thomas

211

Poly(ortho ester amides): Acid-labile Temperature-responsive Copolymers for Potential Biomedical Applications  

PubMed Central

A new, convenient pathway is developed to synthesize highly hydrolytically labile poly(ortho ester amide) (POEA) copolymers that overcomes some of the major weaknesses of the traditional methods of synthesizing poly(ortho esters) and their derivatives. A diamine monomer containing a built-in, stabilized ortho ester group was synthesized and was used for polycondensation with diacid esters, giving rise to a series of POEA copolymers with unique stimuli-responsive properties. The POEA undergoes temperature-responsive, reversible sol-gel phase transition in water. Phase diagrams of the POEA/H2O mixture reveal the concentration-dependent existence of different phases, including hydrogel and opaque or clear solution. Such behavior may be attributed to the temperature-dependent hydrogen-bonding involving the amide groups in the POEA backbone and hydrophobic interactions between POEA chains, and it is tunable by selecting diacid monomers with different chemical structures. The kinetics of POEA mass loss in physiological aqueous buffers and release of a model macromolecular drug, fluorescently labeled dextran, are nearly zero-order, suggesting predominantly surface-restricted polymer erosion. The rates of polymer erosion and drug release are much faster at pH 5.0 than pH 7.4. No cytotoxicity was found for the polymer extracts and the polymer degradation products at concentrations as high as 1 mg/ml. The normal morphology of fibroblasts cultured directly in contact with POEA films was not altered. These novel acid-labile temperature-responsive POEA copolymers may be potentially useful for a wide range of biomedical applications such as minimal invasive delivery of controlled-release drug formulations that respond to biological temperature and acidic-pH environments in cells and tissues. PMID:19281150

Tang, Rupei; Palumbo, R. Noelle; Ji, Weihang; Wang, Chun

2009-01-01

212

Palmer LTER: Dissolved silicic acid-nitrate relationships during austral autumn 1993  

SciTech Connect

The study of biogeochemical processes in representative antarctic marine ecosystems is a priority objective of the US Joint Global Ocean Flux Study. Carbon and bioelement (especially silica) fluxes in the southern oceans are significant on global scales, but are poorly constrained due to undersampling. Consequently, we are unable to construct accurated coupled physical-biogeochemical models or to predict the response of the southern oceans to global environmental change. Additional information has been gathered in this program by measuring nutrient concentrations throughout the study area to help define the regional variability in water-mass distributions and to map the patterns and magnitudes of regional upper-ocean nutrient depletions resulting from biological activity. These studies focus on the dissolved silicic acid-nitrate relationships. 15 refs. 3 figs.

Houlihan, T.; Karl, D.M. (Univ. of Hawaii, Honolulu, HI (United States))

1993-01-01

213

Optimizing Reaction Conditions for the Isomerization of Fatty Acids and Fatty Acid Methyl Esters to Their Branch Chain Products  

Microsoft Academic Search

In order to improve the oxidative stability and cold flow properties of oleic acid or methyl oleate, branch chain isomerization\\u000a was conducted using a beta zeolite catalyst. Reaction conditions of temperature (200–300 °C), pressure (0.1–3.0 MPa), and\\u000a co-catalyst (0–2 wt%) were optimized based on branch chain conversion and the cloud point of the ester following the isomerization\\u000a reaction of oleic acid or

Stephen J. Reaume; Naoko Ellis

2011-01-01

214

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 PMID:16345583

Bobbie, Ronald J.; White, David C.

1980-01-01

215

Evidence of silicic acid leakage to the tropical Atlantic via Antarctic Intermediate Water during Marine Isotope Stage 4  

NASA Astrophysics Data System (ADS)

Antarctic Intermediate Water (AAIW) and Subantarctic Mode Water (SAMW) are the main conduits for the supply of dissolved silicon (silicic acid) from the deep Southern Ocean (SO) to the low-latitude surface ocean and therefore have an important control on low-latitude diatom productivity. Enhanced supply of silicic acid by AAIW (and SAMW) during glacial periods may have enabled tropical diatoms to outcompete carbonate-producing phytoplankton, decreasing the relative export of inorganic to organic carbon to the deep ocean and lowering atmospheric pCO2. This mechanism is known as the "silicic acid leakage hypothesis" (SALH). Here we present records of neodymium and silicon isotopes from the western tropical Atlantic that provide the first direct evidence of increased silicic acid leakage from the Southern Ocean to the tropical Atlantic within AAIW during glacial Marine Isotope Stage 4 (~60-70 ka). This leakage was approximately coeval with enhanced diatom export in the NW Atlantic and across the eastern equatorial Atlantic and provides support for the SALH as a contributor to CO2 drawdown during full glacial development.

Griffiths, James D.; Barker, Stephen; Hendry, Katharine R.; Thornalley, David J. R.; Flierdt, Tina; Hall, Ian R.; Anderson, Robert F.

2013-06-01

216

Effect of silicic acid on arsenate and arsenite retention mechanisms on 6-L ferrihydrite: A spectroscopic and batch adsorption approach  

PubMed Central

The competitive adsorption of arsenate and arsenite with silicic acid at the ferrihydrite-water interface was investigated over a wide pH range using batch sorption experiments, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, extended X-ray absorption fine structure (EXAFS) spectroscopy, and density functional theory (DFT) modeling. Batch sorption results indicate that the adsorption of arsenate and arsenite on the 6-L ferrihydrite surface exhibits a strong pH-dependence, and the effect of pH on arsenic sorption differs between arsenate and arsenite. Arsenate adsorption decreases consistently with increasing pH; whereas arsenite adsorption initially increases with pH to a sorption maximum at pH 7–9, where after sorption decreases with further increases in pH. Results indicate that competitive adsorption between silicic acid and arsenate is negligible under the experimental conditions; whereas strong competitive adsorption was observed between silicic acid and arsenite, particularly at low and high pH. In-situ, flow-through ATR-FTIR data reveal that in the absence of silicic acid, arsenate forms inner-sphere, binuclear bidentate, complexes at the ferrihydrite surface across the entire pH range. Silicic acid also forms inner-sphere complexes at ferrihydrite surfaces throughout the entire pH range probed by this study (pH 2.8 – 9.0). The ATR-FTIR data also reveal that silicic acid undergoes polymerization at the ferrihydrite surface under the environmentally-relevant concentrations studied (e.g., 1.0 mM). According to ATR-FTIR data, arsenate complexation mode was not affected by the presence of silicic acid. EXAFS analyses and DFT modeling confirmed that arsenate tetrahedra were bonded to Fe metal centers via binuclear bidentate complexation with average As(V)-Fe bond distance of 3.27 Å. The EXAFS data indicate that arsenite forms both mononuclear bidentate and binuclear bidentate complexes with 6-L ferrihydrite as indicated by two As(III)-Fe bond distances of ~2.92–2.94 and 3.41–3.44 Å, respectively. The As-Fe bond distances in both arsenate and arsenite EXAFS spectra remained unchanged in the presence of Si, suggesting that whereas Si diminishes arsenite adsorption preferentially, it has a negligible effect on As-Fe bonding mechanisms. PMID:25382933

Gao, Xiaodong; Root, Robert A.; Farrell, James; Ela, Wendell; Chorover, Jon

2014-01-01

217

Development of biodegradable flexible films of starch and poly(lactic acid) plasticized with adipate or citrate esters.  

PubMed

Biodegradable films were produced from blends contained a high amount of thermoplastic starch (TPS) and poly(lactic acid) (PLA) plasticized with different adipate or citrate esters. It was not possible to obtain pellets for the production of films using only glycerol as a plasticizer. The plasticization of the PLA with the esters and mixture stages added through extrusion was critical to achieve a blend capable of producing films by blow extrusion. Adipate esters were the most effective plasticizers because they interacted best with the PLA and yielded films with appropriate mechanical properties. PMID:23218260

Shirai, M A; Grossmann, M V E; Mali, S; Yamashita, F; Garcia, P S; Müller, C M O

2013-01-30

218

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

219

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

220

Synthesis of trimethylolpropane esters of oleic acid by Lipoprime 50T  

Microsoft Academic Search

The ability of the commercial lipolytic enzyme Lipoprime 50T to catalyze the biotechnologically important synthesis of the\\u000a biodegradable and environmentally acceptable trimethylolpropane (2-ethyl-2-(hydroxymethyl)-1,3-propanediol) ester of oleic\\u000a acid was investigated. Simple and accurate thin-layer chromatography and computer analysis methods were used that enable one\\u000a to follow changes of all reaction mixture components simultaneously. The processes of transesterification and esterification\\u000a were compared.

Vita Kiriliauskait?; Vida Bendikien?; Benediktas Juodka

221

Multicolored electrochromism in 4,4'-biphenyl dicarboxylic acid diethyl ester.  

PubMed

We investigated the properties of 4,4'-biphenyl dicarboxylic acid diethyl ester (PCE). The PCE underwent a 2-step reduction at -1.5 V and -2.2 V. The color of the PCE changed from colorless to yellow in the first step and consequently to red in the second reduction step. A PCE based EC cell using an NiO-modified electrode was also fabricated. The NiO electrode worked as a counter reaction material for PCE reduction. The PCE-NiO cell achieved multi-coloration ranging from colorless to yellow and red, and also achieved high coloration efficiency and long term switching stability. PMID:21614355

Imaizumi, Kinji; Watanabe, Yuichi; Nakamura, Kazuki; Omatsu, Takashige; Kobayashi, Norihisa

2011-07-01

222

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.

223

Linear and cyclic ester Oligomers of succinic acid and 1,4-butanediol: Biocatalytic synthesis and characterization  

Microsoft Academic Search

The lipase-catalyzed synthesis of cyclic ester oligomers from non-activated succinic acid (A) and 1,4-butanediol (B) in the presence of immobilized Candida antarctica lipase B was investigated. Batch and pulse fed-batch systems were implemented to increase the formation of cyclic ester products. The substrate conversions after 24 h were 86% and 95% under batch and fed-batch operation, respectively and the product

D. I. Habeych Narvaez; G. Eggink; C. G. Boeriu

2011-01-01

224

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

225

Effect of ester side chains and solvent polarity on the electronic spectra and coordination chemistry of aquacyanocobyrinic acid heptamethylester  

Microsoft Academic Search

Aquacyanocobyrinic acid heptamethyl ester (Aquacyanocobester) has been prepared from vitamin B12 after converting the seven amide side chains into methyl esters. The solvent dependence of the absorption spectrum of aquacyanocobester has shown that the wavelengths of the ?-band varied from 362.5 nm in non-polar solvent (CCl4) through 359.5 nm in a more polar solvent (CH3CN) to 353 nm in protic

M. S. A Hamza

1998-01-01

226

Caffeic acid phenethyl ester (CAPE): correlation of structure and antioxidant properties.  

PubMed

Caffeic acid phenethyl ester (CAPE), a plant polyphenolic concentrated in honeybee propolis, has been found to be biologically active in a variety of pathways. The aim of this study was to determine the antioxidant activity of CAPE using different methods such as total antioxidant activity by the thiocyanate method, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid radicals, 1,1-diphenyl-2-picryl-hydrazyl free radicals, N,N-dimethyl-p-phenylenediamine dihydrochloride radicals and superoxide anion radicals scavenging activities, reducing power and ferrous ions (Fe(2+)) chelating activities. CAPE showed 97.9% inhibition on lipid peroxidation of linoleic acid emulsion. On the other hand, butylated hydroxyanisole, butylated hydroxytoluene, ?-tocopherol and trolox indicated an inhibition of 87.3, 97.6, 75.3 and 90.3% on peroxidation in the same system, respectively. PMID:21631390

Göçer, Hülya; Gülçin, Ilhami

2011-12-01

227

TREATMENT OF WOOD WITH POLYSILICIC ACID DERIVED FROM SODIUM SILICATE FOR FUNGAL DECAY PROTECTION1  

Microsoft Academic Search

The aim of this study was to investigate safer, more inexpensive chemicals derived from sodium silicate that can be used to protect wood against fungal degradation. Desiccant and surfactant properties of sodium silicate-derived products have been used since the early 19th century and may find application for wood decay protection. In our study, wood was impregnated with 19.5% sodium silicate

George C. Chen

228

Alkyl esters of hydroxycinnamic acids with improved antioxidant activity and lipophilicity protect PC12 cells against oxidative stress.  

PubMed

Hydroxycinnamic acids (HCAs) are phenolic compounds present in dietary plants, which possess considerable antioxidant activity. In order to increase the lipophilicity of HCAs, with the aim of improving their cellular absorption and expansion of their use in lipophilic media, methyl, ethyl, propyl and butyl esters of caffeic acid and ferulic acid have been synthesized. All caffeate esters had a slightly lower DPPH IC(50) (13.5-14.5 ?M) and higher ferric reducing antioxidant power (FRAP) values (1490-1588 mM quercetin/mole [mMQ/mole]) compared to caffeic acid (16.6 ?M and 1398 mMQ/mole, respectively) in antioxidant assays. In contrast, ferulate esters were less active in DPPH (56.3-74.7 ?M) and FRAP assays (193-262 mMQ/mole) compared to ferulic acid (44.6 ?M and 324 mMQ/mole, respectively). Redox properties of HCAs were in line with their antioxidant capacities, so that compounds with higher antioxidant activities had lower oxidation potentials. Measurement of partition coefficients disclosed the higher lipophilicity of the esters compared to parent compounds. All esters of caffeic acid significantly inhibited hydrogen peroxide-induced neuronal PC12 cell death assessed by MTT assay at 5 and 25 ?M. However, caffeic acid, ferulic acid and ferulate esters were not able to protect the cells. In conclusion, these findings suggest that alkyl esterification of some HCAs augments their antioxidant properties as well as their lipophilicity and as a consequence, improves their cell protective activity against oxidative stress. These compounds could have useful applications in conditions where oxidative stress plays a pathogenic role. PMID:22210493

Garrido, Jorge; Gaspar, Alexandra; Garrido, E Manuela; Miri, Ramin; Tavakkoli, Marjan; Pourali, Samaneh; Saso, Luciano; Borges, Fernanda; Firuzi, Omidreza

2012-04-01

229

Probing the reactivity of o-phthalaldehydic acid/methyl ester: synthesis of N-isoindolinones and 3-arylaminophthalides.  

PubMed

A new method for the synthesis of N-substituted isoindolinones and 3-arylaminophthalides was developed through aza-Wittig/cyclisation. The reaction of o-phthalaldehydic acid methyl ester with benzylic, aromatic and aliphatic azides gave N-isoindolinones whereas reaction of o-phthalaldehydic acid with the aromatic azides gave 3-arylaminophthalides. PMID:23939425

Mamidyala, Sreeman K; Cooper, Matthew A

2013-09-28

230

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 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...

2012-07-01

231

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

232

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 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...

2011-07-01

233

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

234

QSTR studies regarding the ECOSAR toxicity of benzene-carboxylic acid' esters to fathead minnow fish (Pimephales promelas).  

PubMed

The present work employs 152 benzene-carboxylic acid' esters having computed the toxicity within the range [2.251, 10.222] for fathead minnow fish (Pimephales promelas). Calibration set includes many pairs having very similar chemical structure, size, shape and hydrophilicity, but very different value of ECOSAR toxicity or vice versa. The QSTR study, which uses all esters as calibration set, emphasized a large percent (16.2%) of outliers. In this QSTR study most of the estimated values of toxicity for outliers are much lower than ECOSAR toxicity. The LogP and some aromaticity descriptors are predictors. The best QSTR for esters having low value (< 5.5) of ECOSAR toxicity and the best QSTR for esters having high value (> 5.5) of ECOSAR toxicity are obtained when the number of outliers is very small. These QSTRs are different enough and highlight opposite influences of certain descriptors on toxicity. The results emphasize two possibilities: (a) the esters having low value of ECOSAR toxicity and the esters having high value of ECOSAR toxicity are included in two different classes from the point of view of structure-toxicity relationship and/or (b) many high values of ECOSAR toxicity are wrong. By comparison, a QSTR using experimental values of toxicity against rats for 37 benzene-carboxylic esters included in the same database gives good correlation experimental/computed values of toxicity, the number of outliers is null and the result of validation test is good. PMID:24724900

Tarko, Laszlo; Putz, Mihai V; Ionascu, Cosmin; Putz, Ana-Maria

2014-01-01

235

A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters.  

PubMed

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 37°C 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. PMID:21915852

Urban, Jiri; Svec, Frantisek; Fréchet, Jean M J

2012-02-01

236

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 37°C 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. PMID:21915852

Urban, Jiri; Svec, Frantisek; Frechet, Jean M.J.

2011-01-01

237

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. PMID:24455184

Zarubina, S.A.; Uporov, I.V.; Fedorchuk, E.A.; Fedorchuk, V.V.; Sklyarenko, A.V.; Yarotsky, S.V.; Tishkov, V.I.

2013-01-01

238

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 5 K/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

239

Lysosomal acid lipase mutations that determine phenotype in Wolman and cholesterol ester storage disease.  

PubMed

Mechanisms producing the divergent phenotypes, Wolman disease (WD) and cholesterol ester storage disease (CESD), associated with the genetic deficiency of human lysosomal acid lipase/cholesterol ester hydrolase (hLAL) function were investigated with the determination of HLAL activity levels, mRNA and protein expression, and defects in structural gene sequences in cells from three WD and five CESD patients. Measured with natural substrates, HLAL activities were all below 2% of normal, regardless of phenotype. Immunoblotting showed a lack of detectable hLAL protein in all mutant fibroblasts. Four CESD, but no WD genomes contained at least one allele with a specific exon 8 splice junction mutation, c.894 G>A, that encodes a shortened form of hLAL mRNA. Other CESD mutations were identical in type to the WD defects: nucleotide deletions (positions 397, 684, 980), insertions (594), or substitutions (193, 347) that result in premature terminations precluding any function. The only exception was a substitution at nucleotide 866 in the CESD case without an exon 8 splicing mutation; expression of the predicted S289C change in a transfection assay produced a low, but clearly measurable, level of acid esterase activity. Although it is not easily demonstrated in conventional assays, CESD is distinct from WD in that at least one mutant allele has the potential to produce enough residual enzymatic function to ameliorate the phenotype; in the majority of CESD cases this may come from a single, easily detected, splicing mutation in one allele. PMID:10562460

Anderson, R A; Bryson, G M; Parks, J S

1999-11-01

240

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

241

Electrical properties of pSi/[6,6] phenyl-C61 butyric acid methyl ester/Al hybrid heterojunctions: Experimental and theoretical evaluation of diode operation  

NASA Astrophysics Data System (ADS)

In this work, we analyze electrically the Al/p-Si/[6,6] phenyl-C61 butyric acid methyl ester/Al hybrid heterojunction. The barrier height at the p-Si/PCBM interface corresponding to the difference between Si valence band edge and the lowest unoccupied molecular orbital energy level of PCBM is studied with current-voltage (J-V) and capacitance-voltage (C-V) methods and determined to be ?0.55 eV. This value is in agreement with the onset energy of spectrally resolved photocurrent measurements presented in a previous publication [Matt et al., Adv. Mater. 22, 647 (2010)]. For the J-V characteristics, a thorough model based on an interface generation-recombination current is proposed. All relevant energy levels for this model are obtained experimentally. As origin of the large reverse current, the thermal generation of charge carriers throughout the Si depletion region is identified by the thermal activation measurements.

Bednorz, Mateusz; Fromherz, Thomas; Matt, Gebhard J.; Brabec, Christoph J.; Scharber, Markus; Serdar Sariciftci, N.

2012-12-01

242

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

243

Carotenoids and their fatty acid esters in the petals of Adonis aestivalis.  

PubMed

Carotenoids and their fatty acid esters were investigated in the petals of Adonis aestivalis by UV-VIS, (1)H-NMR, FAB-MS, and CD spectrometry. (3S,3'S)-astaxanthin (diester: 72.2%, monoester: 13.8%, free: 1.4%) and (3S)-adonirubin (monoester: 13.8%, free: 0.3%) were identified as the major components. The fatty acids esterified with astaxanthin and adonirubin were assigned as C18:0, C18:1, C16:0, C16:1, C14:0, C12:0, and C10:0 from the FAB-MS spectral data. PMID:21263199

Maoka, Takashi; Etoh, Tetsuji; Kishimoto, Sanae; Sakata, Syusaku

2011-01-01

244

Behavior of the rare earth elements and other trace elements during interactions between acidic hydrothermal solutions and silicic volcanic rocks, southwestern Japan  

Microsoft Academic Search

Rare earth elements and other trace elements in some Roseki deposits (mostly pyrophyllite and sericite), silicastones, alunites, and related rocks were determined in order to examine behavior of the trace elements in the acidic hydrothermal alteration of silicic volcanic rocks. The analyzed concentrations were normalized to the probable unaltered original rock values inferred from the averaged data of some silicic

Y. Terakado; T. Fujitani

1998-01-01

245

The fusion of erythrocytes by fatty acids, esters, retinol and ?-tocopherol  

PubMed Central

1. The ability of a number of carboxylic acids, their esters, retinol and ?-tocopherol to induce fusion of hen erythrocytes in vitro was investigated. 2. Some 30 different fat-soluble substances (100?g/ml) were found to cause the formation of multinucleated erythrocytes with a suspension of 3×108 erythrocytes/ml. The most effective agents induced fusion within 5–10min at 37°C; some substances required about 1h. 3. Inclusion of Dextran 60C in the test medium minimized colloid osmotic lysis caused by exogenous lipids that induce cell fusion. 4. Cell swelling, followed by cell adhesion, was then seen to precede cell fusion. 5. Fusion occurred with C10–C14 saturated carboxylic acids, with unsaturated, longer-chain carboxylic acids and their mono-esters; retinol, and to a lesser extent ?-tocopherol, also caused cell fusion. 6. C6–C9, C15, C16 and C18 saturated carboxylic acids did not induce fusion within 4h; glyceryl dioleate was only weakly active, and glyceryl trioleate was inactive in the test system. 7. Fusion was facilitated by a high ratio of chemical agents to cell number and by incubation between pH5 and 6. It was inhibited by EDTA and by serum albumin. 8. Glyceryl mono-oleate caused both a similar fusion of several species of mammalian erythrocyte and the interspecific fusion of human and chicken erythrocytes. 9. The term `fusogenic' is proposed to describe chemical, viral and physical agents that cause membranes to fuse. 10. The biochemical mechanisms involved and the possible biological significance of membrane fusion by fusogenic lipids are discussed. ImagesPLATE 2PLATE 1 PMID:4204034

Ahkong, Q. F.; Fisher, D.; Tampion, W.; Lucy, J. A.

1973-01-01

246

Supported phosphate and carbonate salts for heterogeneous catalysis of triglycerides to fatty acid methyl esters  

NASA Astrophysics Data System (ADS)

Fatty acid methyl esters made from vegetable oil, or biodiesel, have been identified as a substitute for diesel derived from crude oil. Biodiesel is currently made using a homogeneous base catalyst to perform the transesterification of triglycerides with methanol to generate fatty acid methyl esters (FAME). The use of a homogeneous catalyst necessitates additional purification of the product and byproducts before sale, and the catalyst is consumed and discarded. The development of a heterogeneous basic catalyst for the production of FAME is desirable. Tribasic phosphate salts and dibasic carbonate salts are active for the production of FAME but generally operate as homogeneous catalysts. Supporting these phosphate and carbonate salts on mesoporous MCM-41, microporous silica gel, and nonporous a-alumina proved successful to greater or lesser degrees depending on the identity of the support and pretreatment of the support. Although these salts were supported and were active for the production of FAME from canola oil, they proved to be operating as homogeneous catalysts due to leaching of the active species off the surface of the support. Further investigation of the active species present in the tribasic phosphate catalysts identified the active support as orthophosphate, and NMR studies revealed the phosphorus to be present as orthophosphate and diphosphate in varying proportions in each catalyst. Evaluation of the acid-washing support pretreatment process revealed that the exposure of the support to acid plays a large role in the development of activity on the surface of the catalyst, but manipulation of these parameters did not prevent leaching of the active site off the surface of the catalyst. Alternate methods of support pretreatment were no more effective in preventing leaching. Tribasic phosphate supported on silica gel is not effective as a heterogeneous catalyst for FAME production from triglycerides because of the lack of stability of the phosphate on the support. The support is not stable under the reaction conditions, and alternatives should be explored to develop a heterogeneous base catalyst for the production of FAME.

Britton, Stephanie Lynne

247

Kinetic resolution of racemic mandelic Acid esters by n,n'-dioxide-scandium-complex-catalyzed enantiomer-selective acylation.  

PubMed

A simple and efficient acylative kinetic resolution of racemic mandelic acid esters was accomplished with a chiral N,N'-dioxide-scandium(III) complex under mild and base-free reaction conditions. A variety of mandelic acid esters performed well in the reaction, obtaining both acylated products (up to 49% yield, 97% ee) and recovered substrates (up to 49% yield, 95% ee) in high enantioselectivities with perfect selectivity factors (up to 247). The enantioselective recognition and catalytic models were also proposed for the catalytic KR reaction. PMID:25284213

Zhang, Yuheng; Liu, Xiaohua; Zhou, Lin; Wu, Wangbin; Huang, Tianyu; Liao, Yuting; Lin, Lili; Feng, Xiaoming

2014-11-24

248

Retention indices, relative response factors, and mass spectra of trifluoroethyl and heptafluorobutyl esters of carboxylic acids determined by capillary GC/MS  

SciTech Connect

The GC/MS characteristics of carboxylic acid esters prepared from fluorine-containing alcohols were compared to those of methyl esters. The GC retention of 2,2,2-trifluoroethyl (TFE) esters was less than, and 2,2,3,3,4,4,4-heptafluoro-1-butyl (HFB) esters approximately equivalent to that of methyl esters. The peak shape of both TFE and HFB esters was slightly superior to that of methyl esters. Mass spectra of TFE and HFB aliphatic esters show significantly more intense molecular and key fragment ions than those of methyl esters. Also, owing to their significantly higher molecular weights, TFE or HFB ester molecular ions and most fragment ions of interest occur at significantly higher m/z values than most potential interfering ions. The GC retention indices, relative GC/MS total ion current response factors, and 70 eV electron impact mass spectra of about 70 TFE and 70 HFB carboxylic acid esters are reported. Results from analysis of a TFE/HFB esterified petroleum carboxylic acid concentrate are discussed in detail. 26 refs., 17 figs., 3 tabs.

Yu, S.K.-T.; Vrana, R.P.; Green, J.B.

1990-11-01

249

Application of specific response factors in the gas chromatographic analysis of methyl esters of fatty acids with flame ionization detectors  

Microsoft Academic Search

The relative responses for flame ionization detectors in the analysis of the longer chain fatty acid methyl esters are shown\\u000a to correlate with the theoretical responses based on weight percent content of “active” carbon. While particularly affecting\\u000a estimation of the shorter chain length saturated fatty acids, these corrections have a less marked effect on the estimation\\u000a of unsaturated fatty acids.

R. G. Ackman; J. C. Sipos

1964-01-01

250

Separation and purification of the antioxidant compounds, caffeic acid phenethyl ester and caffeic acid from mushrooms by molecularly imprinted polymer.  

PubMed

Caffeic acid phenethyl ester (CAPE) and caffeic acid (CA), two naturally occurring phenolic antioxidants, have been reported to have a diversity of biological activities. In this investigation, a novel approach to separate and enrich CAPE and CA from 25 species of mushrooms using molecularly imprinted polymers (MIPs) as the sorbent material is reported. The MIPs were synthesized using CAPE as the template, and its adsorption behavior was investigated in detail. In comparison with C18-solid phase extraction (SPE), MIP-SPE displayed high selectivity and good affinity for CAPE and CA. The antioxidant potential of the mushroom extracts, before and after preconcentration using MIPs, was assayed by inhibition of erythrocyte hemolysis and lipid peroxidation. Application of MIPs with a high affinity toward CAPE and CA provides a novel method for obtaining active compounds from natural products. PMID:23561222

Li, Ning; Ng, Tzi Bun; Wong, Jack Ho; Qiao, Ji Xuan; Zhang, Ye Ni; Zhou, Rong; Chen, Rong Rong; Liu, Fang

2013-08-15

251

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 90°C 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 sulfate–16% 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. PMID:9797298

Janes, M. E.; Nannapaneni, R.; Proctor, A.; Johnson, M. G.

1998-01-01

252

Rice hull ash and silicic acid as adsorbents for concentration of bacteriocins  

PubMed

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 90 degreesC 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 sulfate-16% 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. PMID:9797298

Janes; Nannapaneni; Proctor; Johnson

1998-11-01

253

Mobilization of lead by esters of meso-2,3-dimercaptosuccinic acid.  

PubMed

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. PMID:2547977

Singh, P K; Jones, M M; Xu, Z; Gale, G R; Smith, A B; Atkins, L M

1989-01-01

254

Ester synthesis in an aqueous environment by Streptococcus thermophilus and other dairy lactic acid bacteria.  

PubMed

The ability of Streptococcus thermophilus ST1 and 19 other dairy lactic acid bacteria (LAB) to synthesize esters was investigated in an aqueous environment. These LAB were able to synthesize esters from alcohols and glycerides via a transferase reaction (alcoholysis) in which fatty acyl groups from glycerides were transferred to alcohols. S. thermophilus ST1 was active on tributyrin and on di- or monoglycerides of up to C10 with ethanol as the acyl acceptor. This strain was also active on a diglyceride of C6 and monoglyceride of C8 with 2-phenyl ethanol as the acyl acceptor. Alcoholysis occurred preferentially over hydrolysis. S. thermophilus ST1 had an apparent K(m) value of 250 mM for ethanol and an apparent K(m) value of 1.3 mM for tributyrin, measured against whole cells. Around 80% of both the transferase activity and the esterase activity were detected in the cell-free extract (CFE) of strain ST1. Both activities in the CFEs of five LAB tested were, to a similar degree, enhanced slightly by growth in the presence of ethanol and tributyrin. Using tributyrin and ethanol as substrates, the transferase activities ranged over 0.006-1.37 units/mg cell dry weight among the LAB tested and were both species- and strain-dependent. PMID:12819958

Liu, S-Q; Holland, R; Crow, V L

2003-11-01

255

Fabrication of biodegradable poly(ester-amide)s based on tyrosine natural amino acid.  

PubMed

N,N'-Bis[2-(methyl-3-(4-hydroxyphenyl)propanoate)]isophthaldiamide (5), a novel diol monomer containing chiral group, was prepared by the reaction of S-tyrosine methyl ester (3) with isophthaloyl dichloride (4a). A new family of optically active and potentially biodegradable poly(ester-amide)s (PEAs) based on tyrosine amino acid were prepared by the polycondensation reaction of diol monomer 5 with several aromatic diacid chlorides. The resulting new polymers were obtained in good yields with inherent viscosities ranging between 0.25 and 0.42 dL/g and are soluble in polar aprotic solvents. They showed good thermal stability and high optical purity. The synthetic compounds were characterized and studied by FT-IR, 1H-NMR, specific rotation, elemental and thermogravimetric analysis (TGA) techniques and typical ones by 13C-NMR, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) analysis. Soil burial test of the diphenolic monomer 5, and obtained PEA6a, and soil enzymatic assay showed that the synthesized diol and its polymer are biologically active and probably biodegradable in soil environment. PMID:21607747

Abdolmaleki, Amir; Mallakpour, Shadpour; Borandeh, Sedigheh; Sabzalian, Mohammad R

2012-05-01

256

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, Patrícia

2014-03-15

257

Soybean biodiesel methyl esters, free glycerin and acid number quantification by 1H nuclear magnetic resonance spectroscopy.  

PubMed

Production of alternative fuels, such as biodiesel, from transesterification of vegetable oil driven by heterogeneous catalysts is a promising alternative to fossil diesel. However, achieving a successful substitution for a new renewable fuel depends on several quality parameters. (1)H NMR spectroscopy was used to determine the amount of methyl esters, free glycerin and acid number in the transesterification of soybean oil with methanol in the presence of hydrotalcite-type catalyst to produce biodiesel. Reaction parameters, such as temperature and time, were used to evaluate soybean oil methyl esters rate conversion. Temperatures of 100 to 180 °C and times of 20 to 240 min were tested on a 1 : 12 molar ratio soybean oil/methanol reaction. At 180 °C/240 min conditions, a rate of 94.5 wt% of methyl esters was obtained, where free glycerin and free fatty acids were not detected. PMID:23225640

Coral, Natasha; Rodrigues, Elizabeth; Rumjanek, Victor; Zamian, José Roberto; da Rocha Filho, Geraldo Narciso; da Costa, Carlos Emmerson Ferreira

2013-02-01

258

First confirmation of human diarrhoeic poisonings by okadaic acid esters after ingestion of razor clams ( Solen marginatus) and green crabs ( Carcinus maenas) in Aveiro lagoon, Portugal and detection of okadaic acid esters in phytoplankton  

Microsoft Academic Search

A new outbreak of human diarrhoeic poisonings (DSP) with esters of okadaic acid (OA) was confirmed after ingestion of razor clams (Solen marginatus) harvested at Aveiro lagoon (NW Portugal) in the summer of 2001. Accumulation of marine toxins in second order consumers was investigated in the edible parts of a shellfish predator abundant at Aveiro lagoon, the green crab Carcinus

Paulo Vale; Maria Antónia de M. Sampayo

2002-01-01

259

Fumaric acid and its esters: an emerging treatment for multiple sclerosis with antioxidative mechanism of action.  

PubMed

Fumaric acid was originally therapeutically used in psoriasis. Several lines of evidence have demonstrated immunomodulatory but also neuroprotective 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 dimethylfumarate (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 experiments in the mouse model of central nervous system demyelination, MOG-induced experimental autoimmune encephalomyelitis, revealed a clear preservation of myelin and axonal density in the plaque. Molecular studies showed that this is based on the antioxidative mechanism of action via induction of the transcription factor Nrf-2. A phase II clinical trial in relapsing-remitting multiple sclerosis (RRMS) patients with dimethylfumarate showed a significant reduction in the number of gadolinium enhancing lesions after 24weeks. PMID:21414846

Gold, R; Linker, R A; Stangel, M

2012-01-01

260

Continuous lipase-catalyzed production of fatty acid ethyl esters from soybean oil in compressed fluids.  

PubMed

This work investigates the continuous production of fatty acid ethyl esters from soybean oil in compressed fluids, namely carbon dioxide, propane and n-butane, using immobilized Novozym 435 as catalyst. The experiments were performed in a packed-bed bioreactor evaluating the effects of temperature in the range of 30-70 degrees C, from 50 to 150 bar, oil to ethanol molar ratio of 1:6-1:18 and solvent to substrates mass ratio of 4:1-10:1. In contrast to the use of carbon dioxide and n-butane, results showed that lipase-catalyzed alcoholysis in a continuous tubular reactor in compressed propane might be a potential route to biodiesel production as high reaction conversions were achieved at mild temperature (70 degrees C) and pressure (60 bar) conditions in short reaction times. PMID:19616937

Dalla Rosa, C; Morandim, M B; Ninow, J L; Oliveira, D; Treichel, H; Oliveira, J Vladimir

2009-12-01

261

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

262

[Comparative assessment of Cladophora, Spirogyra and Oedogonium biomass for the production of fatty acid methyl esters].  

PubMed

The use of alternative fuels for the mitigation of ecological impacts by use of diesel has been focus of intensive research. In the present work, algal oils extracted from cultivated biomass of Cladophora sp., Spirogyra sp. and Oedogonium sp. were evaluated for the lipase-mediated synthesis of fatty acid monoalkyl esters (FAME, biodiesel). To optimize the transesterification of these oils, different parameters such as the alkyl group donor, reaction temperature, stirring time and oil to alcohol ratio were investigated. Four different alcohols i.e. methanol, ethanol, n-propanol and n-butanol were tested as alkyl group donor for the biosynthesis FAME and methanol was found to be the best. Similarly, temperature 50 C and stirring time of 6 h were optimized for the transesterification of oils with methanol. The maximum biodiesel conversions from Cladophora (75.0%), Spirogyra (87.5%) and Oedogonium (92.0%) were obtained when oil to alcohol ratio was 1 : 8. PMID:25272756

Haq, I; Muhammad, A; Hameed, U

2014-01-01

263

Experimental and computational thermochemical study of 2- and 3-thiopheneacetic acid methyl esters.  

PubMed

Thiophene-based compounds have widespread use in modern drug design, biodiagnostics, electronic and optoelectronic devices, and conductive polymers. The present study reports an experimental and computational thermochemical study on the relative stabilities of 2- and 3-thiopheneacetic acid methyl esters. The enthalpies of combustion and vaporization were measured by a rotating-bomb combustion calorimeter, Calvet microcalorimetry, and correlation gas chromatography, and the gas-phase enthalpies of formation at T=298.15 K were determined. Standard ab initio molecular orbital calculations at the G3 level were performed, and a theoretical study of the molecular and electronic structure of the compounds studied was carried out. Calculated enthalpies of formation, using atomization and isodesmic reactions are in very good agreement with the experimental results. PMID:17530748

Roux, María Victoria; Temprado, Manuel; Notario, Rafael; Chickos, James S; Santos, Ana Filipa L O M; da Silva, Manuel A V Ribeiro

2007-06-21

264

Aquatic risk assessment of 2-sulfonato fatty acid methyl ester sodium salt (MES).  

PubMed

The aquatic risk of 2-sulfonato fatty acid methyl ester sodium salt (MES) used in household detergents was assessed. The environmental exposure assessment expressed as predicted environmental concentration (PEC) was determined on the basis of monitoring results from the seven sites of four rivers in the urban area in Tokyo and Osaka. The 95 percentile as well as geometric mean of the MES concentration was found to exhibit a good correlation with the geometric mean of the Biochemical Oxygen Demand (BOD; the latter's regression was greater than 0.99). The predicted no effect concentration (PNEC) for the aquatic environment was estimated by performing chronic assays of algae and daphnia. The risk characterization ratio (RCR: PEC/PNEC) was less than 1. Therefore, it is concluded that MES will not adversely affect the aquatic environment in Japan. PMID:17898473

Miura, Kazuaki

2007-01-01

265

Polar and aliphatic domains regulate sorption of phthalic acid esters (PAEs) to biochars.  

PubMed

Molecular variations among different biochar categories translate into differences in their ability to function as sorbents to three phthalic acid esters (PAEs) representing a gradient in hydrophobicity. The sorption capacity (K(OC)) for all three PAEs was the greatest for amorphous biochars (heat treatment temperature HTT=400 °C), followed by biochars produced at 300 °C, and was best explained by the hydrophobicity of the sorbate. Greater alkyl C content and higher polarity of grass chars versus wood chars prepared at similar temperatures explained both (a) the difference in sorbent strength between feedstocks and (b) the maximum in sorbent strength at relatively low HTTs (300-400 °C). Hydrophobic partitioning into 'soft' alkyl carbon and specific H-bonding involving char-bound O and N groups jointly account for high affinities of PAEs for low-HTT biochars. The results highlight the influence of feedstocks and HTTs on PAEs sorption strength and mechanism. PMID:22705514

Sun, Ke; Jin, Jie; Keiluweit, Marco; Kleber, Markus; Wang, Ziying; Pan, Zezhen; Xing, Baoshan

2012-08-01

266

Synthesis, molecular modeling, and biological evaluation of cinnamic acid metronidazole ester derivatives as novel anticancer agents.  

PubMed

A series of novel cinnamic acid metronidazole ester derivatives have been designed and synthesized, and their biological activities were also evaluated as potential EGFR and HER-2 kinase inhibitors. Compound 3h showed the most potent biological activity (IC50=0.62 microM for EGFR and IC50=2.15 microM for HER-2). Docking simulation was performed to position compound 3h into the EGFR active site to determine the probable binding model. Antiproliferative assay results demonstrated that some of these compounds possessed good antiproliferative activity against MCF-7. Compound 3h with potent inhibitory activity in tumor growth inhibition may be a potential anticancer agent. PMID:20594859

Qian, Yong; Zhang, Hong-Jia; Zhang, Hao; Xu, Chen; Zhao, Jing; Zhu, Hai-Liang

2010-07-15

267

Caffeic Acid phenethyl ester: its protective role against certain major eye diseases.  

PubMed

Abstract As an effective compound found mainly in the honeybee product propolis, caffeic acid phenethyl ester (CAPE) has been commonly utilized as a medicine and remedial agent, in a number of countries. Specifically, it might inhibit nuclear factor kappa B at micromolar concentrations and demonstrate antioxidant, antineoplastic, antiproliferative, cytostatic, antiviral, antibacterial, antifungal, and anti-inflammatory features. This review article summarizes the recent progress regarding the favorable effects of CAPE on a number of eye disease models, including cataract and posterior capsule opacification, corneal diseases, retina and optic nerve-related diseases, ischemia/reperfusion injury of retina, inflammation and infection-related diseases. CAPE has been found to exhibit promising efficacy, with minimal adverse effects, in animal and cell culture studies of several eye diseases. PMID:25100535

Akyol, Sumeyya; Ugurcu, Veli; Balci, Mehmet; Gurel, Ayse; Erden, Gonul; Cakmak, Ozlem; Akyol, Omer

2014-11-01

268

Iron and silicic acid concentrations regulate Si uptake north and south of the Polar Frontal Zone in the Pacific Sector of the Southern Ocean  

Microsoft Academic Search

We investigated the relative roles of Fe and silicic acid availabilities in regulating Si uptake rates across the Polar Frontal Zone in the Pacific Sector of the Southern Ocean (59–68°S, 170°W) during the US JGOFS Antarctic Environment Southern Ocean Process Study (AESOPS). Meridional gradients in silicic acid concentration ([Si(OH)4]) of about 0.25–0.56?Mkm?1 were observed in this area during austral spring

Valerie M. Franck; Mark A Brzezinski; Kenneth H Coale; David M Nelson

2000-01-01

269

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

270

Organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium or azolium enolates.  

PubMed

This tutorial review highlights the organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium/azolium enolates. The generation and synthetic utility of these powerful intermediates is highlighted through their application in various methodologies including aldol-lactonisations, Michael-lactonisations/lactamisations and [2,3]-rearrangements. PMID:24867308

Morrill, Louis C; Smith, Andrew D

2014-09-01

271

Astaxanthin from the red crab langostilla ( Pleuroncodes planipes): optical R\\/ S isomers and fatty acid moieties of astaxanthin esters  

Microsoft Academic Search

The composition of the fatty acids of astaxanthin esters and the distribution of astaxanthin optical RS isomers in the esterified and unesterified astaxanthin fractions extracted from the meal of the pelagic red crab langostilla (Pleuroncodes planipes; Decapoda, Anomura) were determined. Astaxanthin diesters comprised approximately 70%, monoesterified astaxanthin approximately 12%, and unesterified astaxanthin approximately 10% of total carotenoids, respectively. Unidentified carotenes

Gladis Nancy Coral-Hinostroza; Bjørn Bjerkeng

2002-01-01

272

40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...  

Code of Federal Regulations, 2010 CFR

. (1) The chemical substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (PMN P-05-177) is subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this...

2010-07-01

273

Determination of Total Lipids as Fatty Acid Methyl Esters (FAME) by in situ Transesterification: Laboratory Analytical Procedure (LAP)  

SciTech Connect

This procedure is based on a whole biomass transesterification of lipids to fatty acid methyl esters to represent an accurate reflection of the potential of microalgal biofuels. Lipids are present in many forms and play various roles within an algal cell, from cell membrane phospholipids to energy stored as triacylglycerols.

Van Wychen, S.; Laurens, L. M. L.

2013-12-01

274

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 138°E transect (between 30 and 34°N) and the 155°E transect (between 10 and 35°N) 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 23°N, while consistently stable low concentrations of 415-751 nmol L-1 were observed south of 23°N. Surface nitrate+nitrite (N+N) and phosphate (PO43-) were typically depleted to <20 nmol L-1, except for PO43- in the area south of 16°N. 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 23°N. 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 (33.1°N, 138°E). 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

275

Gene cloning and characterization of ?-amino acid ester acyl transferase in Empedobacter brevis ATCC14234 and Sphingobacterium siyangensis AJ2458.  

PubMed

The gene encoding ?-amino acid ester acyl transferase (AET), the enzyme that catalyzes the peptide-forming reaction from amino acid methyl esters and amino acids, was cloned from Empedobacter brevis ATCC14234 and Sphingobacterium siyangensis AJ2458 and expressed in Escherichia coli. This is the first report on the aet gene. It encodes a polypeptide composed of 616 (ATCC14234) and 619 (AJ2458) amino acids residues. The V(max) values of these recombinant enzymes during the catalysis of L-alanyl-L-glutamine formation from L-alanine methylester and L-glutamine were 1,010 U/mg (ATCC14234) and 1,154 U/mg (AJ2458). An amino acid sequence similarity search revealed 35% (ATCC14234) and 36% (AJ2458) identity with an ?-amino acid ester hydrolase from Acetobacter pasteurianus, which contains an active-site serine in the consensus serine enzyme motif, GxSYxG. In the deduced amino acid sequences of AET from both bacteria, the GxSYxG motif was conserved, suggesting that AET is a serine enzyme. PMID:22056425

Abe, Isao; Hara, Seiichi; Yokozeki, Kenzo

2011-01-01

276

On the Rate of Boronate Ester Formation in ortho-Aminomethyl Functionalized Phenyl Boronic Acids  

PubMed Central

The role of the ortho-aminomethyl functional group in phenyl boronic acids for sugar complexation is a topic of debate. To decipher its effect on the kinetics of boronate ester formation, we first performed pseudo-first order kinetics analyses at five pH values up to 4 mM in fructose, revealing a first-order kinetic dependence upon fructose. Under these conditions, the reaction is in equilibrium and does not reach completion, but at 50 mM fructose saturation is achieved revealing zero-order dependence upon fructose. This indicates rate-determining creation of an intermediate prior to reaction with fructose, which we propose involves leaving group departure of inserted solvent. Further, the region of kinetics displaying zero-order dependence has a kinetic isotope effect (KIE) of 1.42, showing involvement of a proton transfer in the leaving group departure. The ratio of forward and reverse rate constants branching from the intermediate shows that fructose is several thousand times more nucleophilic than the solvent. Overall, the data supports a mechanism where the o-aminomethyl group lowers the pKa of the proximal boronic acid and acts as a general-acid (as an ammonium) to facilitate leaving group departure. Consequently, by microscopic reversibility the resulting amine must perform general-base catalysis to deliver fructose. PMID:23441105

Collins, Byron E.; Metola, Pedro

2012-01-01

277

Mutations at the lysosomal acid cholesteryl ester hydrolase gene locus in Wolman disease.  

PubMed Central

The genomic sequences encoding the human lysosomal acid lipase/cholesteryl esterase (sterol esterase; EC 3.1.1.13) have been isolated and sequenced, and the information has been used to identify mutations in both alleles of the gene from a patient with Wolman disease, an autosomal recessive lysosomal lipid storage disorder. The genomic locus consists of 10 exons spread over 36 kb. The 5' flanking region is G+C-rich and has characteristics of a "housekeeping" gene promoter. One of the identified mutations involves the insertion of a T residue after position 634, resulting in the appearance of an in-frame translation stop signal 13 codons downstream. The second mutation is a T-to-C transition at nucleotide 638. This results in a leucine-to-proline substitution at amino acid 179 and is predicted to lead to the disruption of the alpha-helical structure in a highly conserved region of the protein. These mutations are each capable of completely disrupting the catalytic function of the lysosomal acid cholesteryl ester hydrolase; their presence can account for the extreme phenotype of the lysosomal lipid storage disorder manifested in members of this patient's family. Images PMID:8146180

Anderson, R A; Byrum, R S; Coates, P M; Sando, G N

1994-01-01

278

Metabolic engineering of Escherichia coli for production of fatty acid short-chain esters through combination of the fatty acid and 2-keto acid pathways.  

PubMed

Fatty acid short-chain esters (FASEs) are biodiesels that are renewable, nontoxic, and biodegradable biofuels. A novel approach for the biosynthesis of FASEs has been developed using metabolically-engineered E. coli through combination of the fatty acid and 2-keto acid pathways. Several genetic engineering strategies were also developed to increase fatty acyl-CoA availability to improve FASEs production. Fed-batch cultivation of the engineered E. coli resulted in a titer of 1008 mg/L FASEs. Since the fatty acid and 2-keto acid pathways are native microbial synthesis pathways, this strategy can be implemented in a variety of microorganisms to produce various FASEs from cheap and readily-available, renewable, raw materials such as sugars and cellulose in the future. PMID:24440714

Guo, Daoyi; Zhu, Jing; Deng, Zixin; Liu, Tiangang

2014-03-01

279

Metal Extraction by Silyl?Substituted Diphosphonic Acids. III. Ester Group Substituent Effects on Phosphoryl Oxygen Basicity  

Microsoft Academic Search

Partial esters of alkylenediphosphonic acids are powerful metal ion extractants for actinides in all oxidation states. A study of americium extraction by silyl?substituted alkylenediphosphonic acids revealed higher extraction efficiency for these ligands compared to their 2?ethylhexyl analogs. The increased efficiency of silyl extractants could arise from differences in phosphoryl oxygen basicity and\\/or metal complex aqueous phase solubility. Substituent effects for

P. R. Zalupski; D. R. McAlister; D. C. Stepinski; A. W. Herlinger

2003-01-01

280

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

281

Control and analysis of alkyl esters of alkyl and aryl sulfonic acids in novel active pharmaceutical ingredients (APIs)  

Microsoft Academic Search

This article reviews current regulatory guidelines and relevant scientific literature pertaining to the control and analysis of potential genotoxic impurities (PGIs) in new active pharmaceutical ingredients (APIs) with specific reference to a certain sub-class of PGIs, namely alkyl esters of alkyl and aryl sulfonic acids. Sulfonic acids are very important in pharmaceutical R&D employed both as counter-ions in the formation

D. P. Elder; A. Teasdale; A. M. Lipczynski

2008-01-01

282

Omega-3 polyunsaturated fatty acids and cardiovascular disease: an emphasis on omega-3-acid ethyl esters 90 for the treatment of hypertriglyceridemia.  

PubMed

A number of epidemiological/observational studies, as well as large-scale randomized intervention studies, have been conducted to provide evidence for the efficacy of ?-3 fatty acids against atherosclerotic diseases. Currently, ?-3 fatty acids are commercially available in many parts of the world containing the same active ingredients as Lotriga(®) (?-3-acid ethyl esters 90 [O3AE highly concentrated ?-3 fatty acid ethyl esters, consisting of eicosapentaenoic acid-ethyl ester and docosahexaenoic acid-ethyl ester [EPA-E/DHA-E]). A recent head-to-head comparative study of O3AEE90 versus EPA-E demonstrated that O3AEE90 4g/day led to a significantly greater reduction in triglycerides (TG) than EPA-E 1.8g/day and that O3AEE90 2g/day produced comparable effects on TG to those with EPA-E 1.8g/day. While both agents were shown to be useful in lowering TG, the hallmark feature of O3AEE90, that is, the presence of the DHA-E component versus its absence in EPA-E, needs to be further examined for its clinical implications. PMID:25319059

Tatsuno, Ichiro

2014-11-01

283

Role of HCA? (GPR109A) in nicotinic acid and fumaric acid ester-induced effects on the skin.  

PubMed

Nicotinic acid (NA) and fumaric acid esters (FAE) such as monomethyl fumarate or dimethyl fumarate are drugs that elicit a cutaneous reaction called flushing as a side effect. NA is used to reduce progression of atherosclerosis through its anti-dyslipidemic activity and lipid-independent mechanisms involving immune cells, whereas FAE are used to treat psoriasis via largely unknown mechanisms. Both, NA and FAE, induce flushing by the activation of the G-protein-coupled receptor (GPCR) Hydroxy-carboxylic acid receptor 2 (HCA?, GPR109A) in cells of the epidermis. While the wanted effects of NA are at least in part also mediated by HCA?, it is currently not clear whether this receptor is also involved in the anti-psoriatic effects of FAE. The HCA?-mediated flushing response to these drugs involves the formation of prostaglandins D? and E? by Langerhans cells and keratinocytes via COX-1 in Langerhans cells and COX-2 in keratinocytes. This review summarizes recent progress in the understanding of the mechanisms underlying HCA?-mediated flushing, describes strategies to mitigate it and discusses the potential link between flushing, HCA? and the anti-psoriatic effects of FAE. PMID:22743741

Hanson, Julien; Gille, Andreas; Offermanns, Stefan

2012-10-01

284

Effect of ionic liquids on enzymatic synthesis of caffeic acid phenethyl ester.  

PubMed

Although caffeic acid phenethyl ester (CAPE), an active flavonoid, plays an important role in the antioxidant activity of honeybee propolis, the isolation of CAPE from honeybee propolis is time-consuming due to wide variety of impurities present. Therefore, biochemical method to synthesize CAPE was investigated in this study. Since ionic liquids (ILs) possess some unique characteristics as appreciated alternatives to conventional solvents for certain biotransformation, the effect of ILs as reaction media for enzymatic synthesis of CAPE was assessed. Several factors including substrate molar ratio, and reaction temperature affecting the conversion yield of lipase-catalyzed CAPE synthesis were also investigated. Reaction yields were significantly higher in hydrophobic ILs than in hydrophilic ILs (almost zero). Among nine hydrophobic ILs tested, the highest conversion of synthetic reaction was obtained in 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][Tf(2)N]). A reaction temperature of 70 °C was found to give high conversion. In addition, optimal substrate molar ratio between phenethyl alcohol and caffeic acid (CA) was decreased significantly from 92:1 to 30:1 when ILs were used instead of isooctane. PMID:21909673

Ha, Sung Ho; Anh, Tran Van; Lee, Sang Hyun; Koo, Yoon-Mo

2012-01-01

285

Formation of polyol-fatty acid esters by lipases in reverse micellar media.  

PubMed

The synthesis of polyol-fatty acid esters has strong implications in such industries as foods, cosmetics, and polymers. We have investigated these esterification reactions employing the polyols ethylene glycol, 2-monoglyceride, and sugars and their derivatives with the biocatalyst lipase in water/AOT/isooctane reverse micellar media. For the first reaction, 50-60% conversion was achieved and product selectivity toward the monoester over the diester shown possible by employing lipase from Rhizopus delemar. A simple kinetic model based on the formation of acyl-enzyme intermediate accurately predicted the effect of polyol concentration but not the effect of fatty acid or water concentration probably due to the model exclusion of partitioning effects. The success of this reaction in reverse micellar media is due greatly to its capacity to solubilize large quantities of glycol despite the media's overall hydrophobicity. The second reaction, investigated for its potential for production of "mixed" glycerides, also achieved about 50% conversion but had only a small portion of triglyceride in its product distribution. Also, isomerization of the 2-monoglyceride to 1-monoglyceride, followed by hydrolysis of the latter, unfortunately occurred to a significant extent. Attempts at esterification with hexoses and their derivatives such as glucose and mannitol produced no conversion. PMID:18601051

Hayes, D G; Gulari, E

1992-06-01

286

In vitro digestion of citric acid esters of mono- and diglycerides (CITREM) and CITREM-containing infant formula/emulsions.  

PubMed

CITREM is an emulsifier used in the food industry and contains citric acid esters of mono- and diglycerides (GCFE). It is generally recognized as safe but no publication on its digestibility under gastrointestinal conditions and impact on fat digestion was available. It was shown here that fatty acids are released from CITREM by gastric lipase, pancreatic lipase, pancreatic-lipase-related protein 2 and carboxyl ester hydrolase. A two-step in vitro digestion model mimicking lipolysis in the stomach and upper small intestine of term and preterm infants was then used to evaluate the digestibility of CITREM alone, CITREM-containing infant formula and fat emulsions, and isolated GCFE fractions. Overall, it was shown that fat digestion is not significantly changed by the presence of CITREM, and fatty acids contained in CITREM compounds are released to a large extent by lipases. Nevertheless, undigestible water-soluble compounds containing glycerol and citric acid units were identified, indicating that the ester bond between citric acid and glycerol is not fully hydrolyzed throughout the proposed digestion. PMID:24777447

Amara, Sawsan; Patin, Amaury; Giuffrida, Francesca; Wooster, Tim J; Thakkar, Sagar K; Bénarouche, Anaïs; Poncin, Isabelle; Robert, Sylvie; Point, Vanessa; Molinari, Sacha; Gaussier, Hélène; Diomande, Sadia; Destaillats, Frédéric; Cruz-Hernandez, Cristina; Carrière, Frédéric

2014-07-25

287

Structural correlation of unsaturated fatty acid esters through graphical comparison of gas-liquid chromatographic retention times on a polyester substrate  

Microsoft Academic Search

The correlation of structures of esters of certain unsaturated fatty acids is possible through a linear relation when logarithms\\u000a of retention time on polyester substrates are plotted against the number of carbon atoms in the fatty acid chain.\\u000a \\u000a This correlation is independent of any relation to the retention times of the esters of the saturated fatty acids, and depends\\u000a solely

R. G. Ackman

1963-01-01

288

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

289

Morphology and metabolism of hepatocytes cultured in Petri dishes on films and in non-woven fabrics of hyaluronic acid esters  

Microsoft Academic Search

Polymers of hyaluronic acid (Hyal) esters exhibit good tissue compatibility and are available in various geometrical configurations. These properties can be exploited for the design of innovative bioartificial liver support devices (BALSDs) using primary hepatocytes. In this paper, we report a preliminary investigation of the polymer feasibility of the ethyl and the benzyl Hyal ester in the form of films

G. Catapano; L. De Bartolo; V. Vico; L. Ambrosio

2001-01-01

290

Selective synthesis of perfumery grade cyclohexyl esters from cyclohexene and carboxylic acids over ion exchange resins: an example of 100% atom economy  

Microsoft Academic Search

Summary Esterification is important in the perfumery and flavour chemical industry, wherein, both homogeneous and heterogeneous cata- lysts have been widely used. The use of solid acid catalysts can be effective from the view of activity, selectivity, reusability and economy in the manufacture of perfumery esters. This paper delineates a 100% atom economical process for the preparation of cyclohexyl esters

G. D. Yadav; P. K. Goel

2000-01-01

291

Fumaric Acid Esters Stimulate Astrocytic VEGF Expression through HIF-1? and Nrf2  

PubMed Central

Fumaric acid esters (FAE) are oral analogs of fumarate that have recently been shown to decrease relapse rate and disease progression in multiple sclerosis (MS), prompting to investigate their protective potential in other neurological diseases such as amyotrophic lateral sclerosis (ALS). Despite efficacy in MS, mechanisms of action of FAEs are still largely unknown. FAEs are known to activate the transcription factor Nrf2 and downstream anti-oxidant responses through the succination of Nrf2 inhibitor KEAP1. However, fumarate is also a known inhibitor of prolyl-hydroxylases domain enzymes (PhD), and PhD inhibition might lead to stabilization of the HIF-1? transcription factor under normoxic conditions and subsequent activation of a pseudo hypoxic response. Whether Nrf2 activation is associated with HIF-1? stabilization in response to FAEs in cell types relevant to MS or ALS remains unknown. Here, we show that FAEs elicit HIF-1? accumulation, and VEGF release as its expected consequence, in astrocytes but not in other cell types of the central nervous system. Reporter assays demonstrated that increased astrocytic VEGF release in response to FAEs was dependent upon both HIF-1? and Nrf2 activation. Last, astrocytes of transgenic mice expressing SOD1(G93A), an animal model of ALS, displayed reduced VEGF release in response to FAEs. These studies show that FAEs elicit different signaling pathways in cell types from the central nervous system, in particular a pseudo-hypoxic response in astrocytes. Disease relevant mutations might affect this response. PMID:24098549

Wiesner, Diana; Merdian, Irma; Lewerenz, Jan; Ludolph, Albert C.; Dupuis, Luc; Witting, Anke

2013-01-01

292

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

293

Effects of fumaric acid esters on blood-brain barrier tight junction proteins.  

PubMed

The blood-brain barrier (BBB) is composed of a network of tight junctions (TJ) which interconnect cerebral endothelial cells (EC). Alterations in the TJ proteins are common in inflammatory diseases of the central nervous system (CNS) like multiple sclerosis (MS). Modulation of the BBB could thus represent a therapeutic mechanism. One pathway to modulate BBB integrity could be the induction of nuclear-factor (erythroid derived 2) related factor-2 (Nrf2) mediated oxidative stress responses which are targeted by fumaric acid esters (FAE). Here we analyze effects of FAE on the expression of TJ proteins in the human cerebral endothelial cell line hCMEC/D3 and experimental autoimmune encephalomyelitis (EAE). We show that dimethylfumarate (DMF) and its primary metabolite monomethylfumarate (MMF) induce the expression of the Nrf2/NQO1 pathway in endothelial cells. Neither MMF nor DMF had a consistent modulatory effect on the expression of TJ molecules in hCMEC/D3 cells. Tumor necrosis factor (TNF?)-induced downregulation of TJ proteins was at least partially reversed by treatment with FAE. However, DMF had no effect on claudin-5 expression in EAE, despite its effect on the clinical score and infiltration of immune cells. These data suggest that the modulation of the BBB is not a major mechanism of action of FAE in inflammatory demyelinating diseases of the CNS. PMID:24076006

Bénardais, Karelle; Pul, Refik; Singh, Vikramjeet; Skripuletz, Thomas; Lee, De-Hyung; Linker, Ralf A; Gudi, Viktoria; Stangel, Martin

2013-10-25

294

Gallic acid esters from the stem bark of Mimusops elengi L.  

PubMed

Phytochemical investigation of the ethanolic extract of the stem bark of Mimusops elengi L. (Sapotaceae) led to the isolation of new gallic acid esters, characterised as phenyl propanoxyl gallate (1), beta-D-glucopyranosyl (6'-->1'')-beta-D-glucopyranosyl-4''-(4''-ethylphenyl) gallate (2), 2'-(1'''-geranyloxy)-beta-D-glucopyranosyl (6'-->1'')-beta-D-glucopyranosyl-4''-phenoxy gallate (3), beta-D-glucopyranosyl (6'-->1'')-beta-D-glucopyranosyl 3,4,5-trihydroxy benzoate (4), beta-D-glucopyranosyl-(6'-->1'')-beta-D-glucopyranosyl-4''-(4'''-n-butylphenyl) 3,4,5-trihydroxy benzoate (5), beta-D-glucopyranosyl(6'-->1'')-beta-D-rhamnosyl 3,4,5-trihydroxy benzoate (6) and beta-D-(2'-phenyl glucopyranosyl)-(6'-->1'')-(2'', 4''-diphenylrhamnopyranosyl)-3,4,5-trihydroxylbenzoate (7), along with the known compounds: farnon-3-one, stigmasta-5-en-3-beta-ol, olean-18-en-2-one-3-ol, lup-20(29)-en-3beta-ol and stigmasta-5-en-3beta-D-glucopyranoside. Their structures were elucidated on the basis of spectroscopic analyses and chemical reactions. PMID:20496236

Akhtar, Nida; Ali, Mohd; Alam, Mohd Sarwar

2010-06-01

295

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

296

Beneficial effects of caffeic acid phenethyl ester in a rat model of vascular injury.  

PubMed

1. 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-kappaB (NF-kappaB) activation and we correlated NF-kappaB activation to the expression of inducible isoform of cyclo-oxygenase (COX-2) in injured carotids. 2. In control group a significant proliferation of neointima was observed 14 days after balloon angioplasty, which was correlated to an increase of NF-kappaB/DNA binding activity as well as p50/p65 nuclear levels compared to those observed in the carotids from sham-operated rats. Furthermore, NF-kappaB activation was correlated to increased COX-2, but not beta-actin, protein expression. 3. Treatment of rats for 14 days with CAPE (3, 10, 30 mg x kg(-1)) caused a significant inhibition of all the parameters assayed, except beta-actin protein expression. 4. These results indicate that treatment with CAPE may lead to a reduction of neointima formation by inhibiting NF-kappaB activation and suggest that this agent may have therapeutic relevance for the prevention of human restenosis. PMID:12023937

Maffia, Pasquale; Ianaro, Angela; Pisano, Barbara; Borrelli, Francesca; Capasso, Francesco; Pinto, Aldo; Ialenti, Armando

2002-06-01

297

Caffeic acid phenethyl ester reduces spinal cord injury-evoked locomotor dysfunction.  

PubMed

Caffeic acid phenethyl ester (CAPE) is a component of propolis, which is a substance taken from the hives of honeybees, and is known to exhibit an anti-inflammatory activity. Such activity has been thought to be partly based on its potential and specific inhibitory activities toward nuclear factor-?B, a transcription factor. Therefore, in the present study, we evaluated the effect of CAPE on functional locomotor recovery after spinal cord injury (SCI) caused by hemi-transection, because inflammatory responses are a major cause of the secondary injury observed following SCI and play a pivotal role in regulating the pathogenesis of acute and chronic SCI. When CAPE was i.p.-administered at a dosage of 10 µmol/kg, it enhanced the recovery of locomotor function and reduced the lesion size while suppressing the expression of the mRNAs for a pro-inflammatory cytokine interleukin-1? and the inflammatory enzymes, inducible nitric oxide synthase and cyclooxygenase-2. These results suggest CAPE to be a promising therapeutic tool for reducing the secondary neuronal damage following primary physical injury to the spinal cord. PMID:21383505

Kasai, Masaki; Fukumitsu, Hidefumi; Soumiya, Hitomi; Furukawa, Shoei

2011-02-01

298

Enhancing fatty acid ethyl ester production in Saccharomyces cerevisiae through metabolic engineering and medium optimization.  

PubMed

Biodiesels in the form of fatty acyl ethyl esters (FAEEs) are a promising next generation biofuel due to their chemical properties and compatibility with existing infrastructure. It has recently been shown that expression of a bacterial acyl-transferase in the established industrial workhorse Saccharomyces cerevisiae can lead to production of FAEEs by condensation of fatty acyl-CoAs and ethanol. In contrast to recent strategies to produce FAEEs in S. cerevisiae through manipulation of de novo fatty acid biosynthesis or a series of arduous genetic manipulations, we introduced a novel genetic background, which is comparable in titer to previous reports with a fraction of the genetic disruption by aiming at increasing the fatty acyl-CoA pools. In addition, we combined metabolic engineering with modification of culture conditions to produce a maximum titer of over 25?mg/L FAEEs, a 40% improvement over previous reports and a 17-fold improvement over our initial characterizations. Biotechnol. Bioeng. 2014;111: 2200-2208. © 2014 Wiley Periodicals, Inc. PMID:24895195

Thompson, R Adam; Trinh, Cong T

2014-11-01

299

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

2014-02-01

300

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

301

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

302

Caffeic Acid Phenethyl Ester as a Potential Treatment for Advanced Prostate Cancer Targeting Akt Signaling  

PubMed Central

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

303

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

304

Simultaneous production of fatty acid methyl esters and diglycerides by four recombinant Candida rugosa lipase's isozymes.  

PubMed

In this study, the catalytic efficiency of four recombinant CRL (Candida rugosa lipase) isozymes (LIP1-LIP4) towards the production of fatty acid methyl ester (FAME) was compared and evaluated as an alternative green method for industrial applications. The results indicated that the recombinant C. rugosa LIP1 enzyme exhibited the highest catalytic efficiency for FAME production compared to the recombinant C. rugosa LIP2-LIP4 enzymes. The optimal conditions were as follows: pH 7.0, methanol/soybean oil molar ratio: 3/1, enzyme amount: 2U (1.6 ?L), reaction temperature: 20°C, 22 h of reaction time, and 3 times of methanol addition (1 mol/6h), and resulted in 61.5 ± 1.5 wt.% of FAME conversion. The reaction product contained also 10 wt.% of DAG with a ratio of 1,3-DAG to 1,2-DAG of approximately 4:6, and can be potentially used in industrial applications as a food emulsifier. PMID:24594166

Chang, Shu-Wei; Huang, Myron; Hsieh, Yu-Hsun; Luo, Ying-Ting; Wu, Tsung-Ta; Tsai, Chia-Wen; Chen, Chin-Shuh; Shaw, Jei-Fu

2014-07-15

305

Electron Affinity of Phenyl-C61-Butyric Acid Methyl Ester (PCBM)  

SciTech Connect

The gas-phase electron affinity (EA) of phenyl-C61-butyric acid methyl ester (PCBM), one of the best-performing electron acceptors in organic photovoltaic devices, is measured by lowtemperature photoelectron spectroscopy for the first time. The obtained value of 2.63(1) eV is only ca. 0.05 eV lower than that of C60 (2.68(1) eV), compared to a 0.09 V difference in their E1/2 values measured in this work by cyclic voltammetry. Literature E(LUMO) values for PCBM that are typically estimated from cyclic voltammetry, and commonly used as a quantitative measure of acceptor properties, are dispersed over a wide range between -4.3 and -3.62 eV; the reasons for such a huge discrepancy are analyzed here, and the protocol for reliable and consistent estimations of relative fullerene-based acceptor strength in solution is proposed.

Larson, Bryon W.; Whitaker, James B.; Wang, Xue B.; Popov, Alexey A.; Rumbles, Garry; Kopidakis, Nikos; Strauss, Steven H.; Boltalina, Olga V.

2013-07-25

306

New eudesmenoic acid methyl esters from the seed oil of Jatropha curcas.  

PubMed

Three new eudesmenoic acid methyl esters (1-3), as well as five known compounds, including three germacranolides (4-6) and two eudesmanolides (7 and 8), were isolated from the seed oil of Jatropha curcas. The new compounds were elucidated by means of spectroscopic methods, including extensive NMR spectra. In addition, the structure of 8 was confirmed by a single-crystal X-ray diffraction analysis. Among the isolates, compounds 4-6 were the first reported from the genus Jatropha. Using MTS viability assay, the cytotoxicity of compounds 2-8 were evaluated against HL-60, SMMC-7721, A-549, MCF-7, and SW480 human tumor cell lines. Compounds 4 and 5 showed remarkable cytotoxicity against all the tested cell lines with IC50 values from 0.5 to 3.5 ?M, and the new compound 3 displayed selective cytotoxic activity against A-549 cell with an IC50 value of 7.24 ?M, but slight cytotoxicity against HL-60 and MCF-7 with IC50 values of 23.77 and 22.37 ?M, respectively. PMID:23811432

Yang, Yuan-Feng; Liu, Jie-Qing; Li, Zhong-Rong; Li, Yan; Qiu, Ming-Hua

2013-09-01

307

S-(-)-10,11-Dihydroxyfarnesoic Acid Methyl Ester Inhibits Melanin Synthesis in Murine Melanocyte Cells  

PubMed Central

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

308

Phthalate acid esters in Potamogeton crispus L. from Haihe River, China.  

PubMed

This study was conducted in Haihe River, China, in order to assess the ability of Potamogeton crispus L. (P. crispus), a submerged plant, to accumulate phthalic acid esters (PAEs). Dibutyl phthalate (DBP) and di-2-ethylexyl phthalate (DEHP) were measured in samples of water, sediment and P. crispus plant from March to May 2008. The results showed that the highest levels of DBP and DEHP in above-ground tissues appeared during the blooming period of P. crispus, which was consistent with the results obtained with the water samples. Regression analysis reveals that concentrations of PAEs in above-ground tissues were mainly influenced by PAE concentrations in the water of Haihe River. Enrichment of DBP and DEHP in above-ground tissues was observed, with bioconcentration factors (BCFs) of 4.82-83.65Lkg(-1) for DBP and 6.71-93.70Lkg(-1) for DEHP. The distribution pattern of DBP in roots, surface and near root sediments was different from that of DEHP. Concentrations of DBP in near root sediments were lower than those in roots and comparable to those in surface sediments, while concentrations of DEHP in roots were lower than those in near root sediments but higher than those in surface sediments. PMID:19545887

Chi, Jie

2009-09-01

309

Gas-phase preparation of carbonic Acid and its monomethyl ester.  

PubMed

Carbonic acid (H2 CO3 ), an essential molecule of life (e.g., as bicarbonate buffer), has been well characterized in solution and in the solid state, but for a long time, it has eluded its spectral characterization in the gas phase owing to a lack of convenient preparation methods; microwave spectra were recorded only recently. Here we present a novel and general method for the preparation of H2 CO3 and its monomethyl ester (CH3 OCO2 H) through the gas-phase pyrolysis of di-tert-butyl and tert-butyl methyl carbonate, respectively. H2 CO3 and CH3 OCO2 H were trapped in noble-gas matrices at 8?K, and their infrared spectra match those computed at high levels of theory [focal point analysis beyond CCSD(T)/cc-pVQZ] very well. Whereas the spectra also perfectly agree with those of the vapor phase above the ?-polymorph of H2 CO3 , this is not true for the previously reported ?-polymorph. Instead, the vapor phase above ?-H2 CO3 corresponds to CH3 OCO2 H, which sheds new light on the research that has been conducted on molecular H2 CO3 over the last decades. PMID:25196920

Reisenauer, Hans Peter; Wagner, J Philipp; Schreiner, Peter R

2014-10-27

310

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

311

Investigation of 60Co ?-irradiated L-(-) malic acid, N-methyl- DL-valine and L-glutamic acid ?-ethyl ester by electron paramagnetic resonance technique  

NASA Astrophysics Data System (ADS)

The electron paramagnetic resonance spectra of ?-irradiated L-(-) malic acid, N-methyl- DL-valine and L-glutamic acid ?-ethyl ester powders have been investigation at room temperature. Radiation damage centres are attributed to HOOCCH 2?HCOOH, (CH 3) 2?CH(NHCH 3)COOH and C 2H 5OCOCH 2CH 2?(NH 2)COOH radicals, respectively. The spectra have been computer simulated. The EPR parameters of the observed radicals have been determined and discussed.

Ba?kan, M. Halim; Ayd?n, Murat; Osmano?lu, ?emsettin

312

Synthesis and Antioxidant Evaluation of Enantiomerically Pure Bis-(1,2,3-triazolylmethyl)amino Esters from Modified ?-Amino Acids  

PubMed Central

The efforts for synthesis of enantiomerically pure bis-(1,2,3-triazolylmethyl)amino esters 6 are reported in good yields from an in situ generated ?-azidomethyl ketone. Optimum experimental conditions were established for preparation of ?-halomethyl ketones 10 and ?-N,N-dipropargylamino esters 11, all derived from ?-amino acids. The starting materials reacted under conventional click chemistry conditions, revealing a specific reactivity of bromomethyl ketones over chloromethyl ketones. The antioxidant activity of compounds 6 was assayed by DPPH method. The compound 6c with an IC50 of 75.57 ± 1.74??g?mL?1 was the most active. Technically, this methodology allows the preparation of a combinatorial library of analogues with different structural characteristics depending on the nature of the modified ?-amino acids employed in the synthesis. PMID:25386592

Sarmiento-Sánchez, Juan I.; Ochoa-Terán, Adrián; Rivero, Ignacio A.

2014-01-01

313

Synthesis, Chemical and Enzymatic Hydrolysis, and Aqueous Solubility of Amino Acid Ester Prodrugs of 3-Carboranyl Thymidine Analogues for Boron Neutron Capture Therapy of Brain Tumors  

PubMed Central

Various water-soluble L-valine-, L-glutamate-, and glycine ester prodrugs of two 3-Carboranyl Thymidine Analogues (3-CTAs), designated N5 and N5-2OH, were synthesized for Boron Neutron Capture Therapy (BNCT) of brain tumors since the water solubilities of the parental compounds proved to be insufficient in preclinical studies. The amino acid ester prodrugs were prepared and stored as hydrochloride salts. The water solubilities of these amino acid ester prodrugs, evaluated in phosphate buffered saline (PBS) at pH 5, pH 6 and pH 7.4, improved 48 to 6600 times compared with parental N5 and N5-2OH. The stability of the amino acid ester prodrugs was evaluated in PBS at pH 7.4, Bovine serum, and Bovine cerebrospinal fluid (CSF). The rate of the hydrolysis in all three incubation media depended primarily on the amino acid promoiety and, to a lesser extend, on the site of esterification at the deoxyribose portion of the 3-CTAs. In general, 3'-amino acid ester prodrugs were less sensitive to chemical and enzymatic hydrolysis than 5'-amino acid ester prodrugs and the stabilities of the latter decreased in the following order: 5'-valine > 5'-glutamate > 5'-glycine. The rate of the hydrolysis of the 5'-amino acid ester prodrugs in Bovine CSF was overall higher than in PBS and somewhat lower than in Bovine serum. Overall, 5'-glutamate ester prodrug of N5 and the 5'-glycine ester prodrugs of N5 and N5-2OH appeared to be the most promising candidates for preclinical BNCT studies. PMID:22889558

Hasabelnaby, Sherifa; Goudah, Ayman; Agarwal, Hitesh K.; Abd alla, Mosaad S. M.; Tjarks, Werner

2012-01-01

314

Preparation of C18-functionalized Fe3O4@SiO2 core-shell magnetic nanoparticles for extraction and determination of phthalic acid esters in Chinese herb preparations.  

PubMed

The extraction and determination of phthalic acid esters (PAEs) residue in Chinese herbal preparations (CHP) by C18-functionalized magnetic nanoparticles (C18-FS-MNP) has been firstly performed. It was synthesized through coating Fe3O4 nanoparticles with sodium silicate, followed by freeze-drying technique and then modified with C18 groups. C18-FS-MNPs prepared via freeze-drying technique were superior to those particles prepared via common vacuum drying method in terms of dispersion and extraction recovery. C18-FS-MNPs demonstrated obvious enrichment effect for four model PAEs and 478-627-fold enrichment factors were obtained. The limit of detection was <1.89ng/mL and relative standard deviation was ranging from 3.7 to 5.8%. It was successfully applied for determination of trace PAEs residue in CHP with good recoveries. PMID:25213260

Guo, Bize; Ji, Shunli; Zhang, Feifang; Yang, Bingcheng; Gu, Jiangping; Liang, Xinmiao

2014-11-01

315

Therapeutic effects of docosahexaenoic acid ethyl ester in patients with generalized peroxisomal disorders.  

PubMed

Generalized peroxisomal disorders are severe congenital diseases that involve the central nervous system, leading to severe psychomotor retardation, retinopathy, liver disease, and early death. In these disorders, peroxisomes are not normally formed and their enzymes are deficient. Characteristically, plasmalogen synthesis and beta-oxidation of very-long-chain fatty acids (VLCFAs) are affected. We found that patients with generalized peroxisomal disorders have a profound brain deficiency of docosahexaenoic acid (DHA; 22:6n-3) and low DHA concentrations in all tissues and the blood. Given the fundamental role of DHA in neuronal and retinal membranes, a DHA deficiency of this magnitude might be pathogenic. Thus, we studied the possible therapeutic effect of normalizing DHA concentrations in patients with peroxisomal disorders. We chose the DHA ethyl ester (DHA-EE) because of its high degree of purity at daily oral doses of 100-500 mg. This article summarizes the results of treatment of 13 patients with DHA-EE, with some follow-up evidence of clinical improvement. Supplementation with DHA-EE normalized blood DHA values within a few weeks. Plasmalogen concentrations increased in erythrocytes in most patients and after DHA concentrations were normalized, amounts of VLCFAs decreased in plasma. Liver enzymes returned almost to normal in most cases. From a clinical viewpoint, most patients showed improvement in vision, liver function, muscle tone, and social contact. In 3 patients, normalization of brain myelin was detected by magnetic resonance imaging. In 3 others, myelination improved. In a seventh patient, myelination is progressing at a normal rate. These results suggest a fundamental role of DHA in the pathogenesis of Zellweger syndrome. DHA therapy is thus strongly recommended, not only to alleviate symptoms in patients with life-threatening diseases, but also to clarify remaining questions regarding the role of DHA in health and disease. PMID:10618001

Martínez, M; Vázquez, E; García-Silva, M T; Manzanares, J; Bertran, J M; Castelló, F; Mougan, I

2000-01-01

316

Partitioning of Homologous Nicotinic Acid Ester Prodrugs (Nicotinates) into Dipalmitoylphosphatidylcholine (DPPC) Membrane Bilayers  

PubMed Central

The partitioning behavior of a series of perhydrocarbon nicotinic acid esters (nicotinates) between aqueous solution and dipalmitoylphosphatidylcholine (DPPC) membrane bilayers is investigated as a function of increasing alkyl chain length. The hydrocarbon nicotinates represent putative prodrugs, derivatives of the polar drug nicotinic acid, whose functionalization provides the hydrophobic character necessary for pulmonary delivery in a hydrophobic, fluorocarbon solvent, such as perfluorooctyl bromide. Independent techniques of differential scanning calorimetry and 1,6-diphenyl-1,3,5 hexatriene (DPH) fluorescence anisotropy measurements are used to analyze the thermotropic phase behavior and lipid bilayer fluidity as a function of nicotinate concentration. At increasing concentrations of nicotinates over the DPPC mole fraction range examined (XDPPC = 0.6 – 1.0), all the nicotinates (ethyl (C2H5); butyl (C4H9); hexyl (C6H13); and octyl (C8H17)) partition into the lipid bilayer at sufficient levels to eliminate the pretransition, and decrease and broaden the gel to fluid phase transition temperature. The concentration at which these effects occur is chain length-dependent; the shortest chain nicotinate, C2H5, elicits the least dramatic response. Similarly, the DPH anisotropy results demonstrate an alteration of the bilayer organization in the liposomes as a consequence of the chain length-dependent partitioning of the nicotinates into DPPC bilayers. The membrane partition coefficients (logarithm values), determined from the depressed bilayer phase transition temperatures, increase from 2.18 for C2H5 to 5.25 for C8H17. The DPPC membrane/water partitioning of the perhydrocarbon nicotinate series correlates with trends in the octanol/water partitioning of these solutes, suggesting that their incorporation into the bilayer is driven by increasing hydrophobicity. PMID:20227859

Ojogun, Vivian; Vyas, Sandhya M.; Lehmler, Hans-Joachim; Knutson, Barbara L

2010-01-01

317

Partitioning of homologous nicotinic acid ester prodrugs (nicotinates) into dipalmitoylphosphatidylcholine (DPPC) membrane bilayers.  

PubMed

The partitioning behavior of a series of perhydrocarbon nicotinic acid esters (nicotinates) between aqueous solution and dipalmitoylphosphatidylcholine (DPPC) membrane bilayers is investigated as a function of increasing alkyl chain length. The hydrocarbon nicotinates represent putative prodrugs, derivatives of the polar drug nicotinic acid, whose functionalization provides the hydrophobic character necessary for pulmonary delivery in a hydrophobic, fluorocarbon solvent, such as perfluorooctyl bromide. Independent techniques of differential scanning calorimetry and 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence anisotropy measurements are used to analyze the thermotropic phase behavior and lipid bilayer fluidity as a function of nicotinate concentration. At increasing concentrations of nicotinates over the DPPC mole fraction range examined (X(DPPC)=0.6-1.0), all the nicotinates (ethyl (C2H5); butyl (C4H9); hexyl (C6H13); and octyl (C8H17)) partition into the lipid bilayer at sufficient levels to eliminate the pretransition, and decrease and broaden the gel to fluid phase transition temperature. The concentration at which these effects occur is chain length-dependent; the shortest chain nicotinate, C2H5, elicits the least dramatic response. Similarly, the DPH anisotropy results demonstrate an alteration of the bilayer organization in the liposomes as a consequence of the chain length-dependent partitioning of the nicotinates into DPPC bilayers. The membrane partition coefficients (logarithm values), determined from the depressed bilayer phase transition temperatures, increase from 2.18 for C2H5 to 5.25 for C8H17. The DPPC membrane/water partitioning of the perhydrocarbon nicotinate series correlates with trends in the octanol/water partitioning of these solutes, suggesting that their incorporation into the bilayer is driven by increasing hydrophobicity. PMID:20227859

Ojogun, Vivian; Vyas, Sandhya M; Lehmler, Hans-Joachim; Knutson, Barbara L

2010-06-15

318

Regioselective cross-coupling of allylboronic acid pinacol ester derivatives with aryl halides via Pd-PEPPSI-IPent.  

PubMed

The cross-coupling reactions of allylboronic acid pinacol ester derivatives with aryl and heteroaryl halides occurred with high selectivity (>97%) at the ?-carbon of the allylboron reagent in the presence of Pd-PEPPSI-IPent precatalyst and 5 M KOH in refluxing THF. In the case of trisubstituted allylboronates with different substituents on the olefin, minor olefin geometry isomerization was observed (E/Z ? 80/20). PMID:23046477

Farmer, Jennifer L; Hunter, Howard N; Organ, Michael G

2012-10-24

319

Lipase-Catalyzed Synthesis of Saccharide–Fatty Acid Esters Using Suspensions of Saccharide Crystals in Solvent-Free Media  

Microsoft Academic Search

Saccharide–fatty acid esters, important biobased and biodegradable emulsifiers in foods, cosmetics, and pharmaceuticals, were\\u000a produced with high yields and productivity via immobilized Rhizomucor miehei lipase-catalyzed esterification in solvent-free systems at 65 °C. Preliminary experiments demonstrated high rates of reaction\\u000a occurred in the presence of acetone near or above its boiling point, due to the formation of 10–200 ?m suspensions of saccharide\\u000a particles.

Ran Ye; Sang-Hyun Pyo; Douglas G. Hayes

2010-01-01

320

Laundering procedures for removal of 2,4-dichlorophenoxyacetic acid ester and amine herbicides from contaminated fabrics  

Microsoft Academic Search

Denim fabrics were contaminated with 2,4-dichlorophenoxyacetic acid (2,4-D) ester and 2,4-D amine formulations and laundered. The variables examined were pesticide formulations, temperatures, pre-rinse conditions, detergents, ammonia additive, and number of washings. A clean fabric, designated the “transfer fabric”, was laundered with the contaminated denim to assess amounts of herbicide transferred during laundering. Solubility of the formulation was a major factor

Carol Bryan Easley; Joan M. Laughlin; Roger E. Gold; Duane R. Tupy

1983-01-01

321

The metabolic bioactivation of caffeic acid phenethyl ester (CAPE) mediated by tyrosinase selectively inhibits glutathione S-transferase  

Microsoft Academic Search

Glutathione S-transferase (GST) and multidrug resistance-associated proteins (MRPs) play major roles in drug resistance in melanoma. In this study, we investigated caffeic acid phenethyl ester (CAPE) as a selective GST inhibitor in the presence of tyrosinase, which is abundant in melanoma cells. Tyrosinase bioactivates CAPE to an o-quinone, which reacts with glutathione to form CAPE-SG conjugate. Our findings indicate that

Shashi K. Kudugunti; Helen Thorsheim; Mohammad S. Yousef; Lan Guan; Majid Y. Moridani

2011-01-01

322

Inhibitors of mammalian melanocyte tyrosinase: in vitro comparisons of alkyl esters of gentisic acid with other putative inhibitors  

Microsoft Academic Search

To discover safe and effective topical skin-lightening agents, we have evaluated alkyl esters of the natural product gentisic acid (GA), which is related to our lead compound methyl gentisate (MG), and four putative tyrosinase inhibitors, utilizing mammalian melanocyte cell cultures and cell-free extracts. Desirable characteristics include the ability to inhibit melanogenesis in cells (ic50 < 100 ?g\\/mL) without cytotoxicity, preferably

Ernest V Curto; Cecil Kwong; Heino Hermersdörfer; Hansruedi Glatt; Chie Santis; Victoria Virador; Vincent J Hearing; Thomas P Dooley

1999-01-01

323

Inhibition of TVimor Promoter-mediated Processes in Mouse Skin and Bovine Lens by Caffeic Acid Phenethyl Ester1  

Microsoft Academic Search

Caffeic acid phenethyl ester (CAPE) was isolated from propolis (a product of honeybee hives) that has been used in folk medicine as a potent antiinflammatory agent. CAPE is cytotoxic to tumor and virally trans formed but not to normal cells. Our main goal was to establish whether CAPE inhibits the tumor promoter (12-0-tetradecanoylphorbol-13-ace- tate)-induced processes associated with carcinogenesis. Topical treatment

Krystyna Frenkel; Huachen Wei; Ramesh Bhimani; Jose A. Zadunaisky; Thomas Ferrare; Allan H. Conney; Dezider Grunberger

1993-01-01

324

Synthesis of biodegradable lauric acid ester quaternary ammonium salt cationic surfactant and its utilization as calico softener  

Microsoft Academic Search

Esterquat cationic surfactant was considered as a new type of biodegradable material utilized as a textile softening agent. In this work, cationic lauric ester quaternary ammonium salt (N-(2-hydroxyl-3-lauryloyloxypropyl) dimethyldodecylammonium chloride (HDAC)) was obtained via reaction between lauric acid and N-(2,3-epoxypropyl) dodecyldimethyl ammonium chloride (DCSA) synthesized from dodecyl dimethylammonium (DTA) and epichlorohydrin (EPIC). The optimum synthesis conditions for DCSA were found

Zongcheng Miao; Jianzhou Yang; Lei Wang; Yong Liu; Long Zhang; Xuelei Li; Lei Peng

2008-01-01

325

Rigid urethane foams from hydroxymethylated castor oil, safflower oil, oleic safflower oil, and polyol esters of castor acids  

Microsoft Academic Search

Castor, safflower, and oleic safflower oil derivatives with enhanced reactivity and hydroxyl group content were prepared by\\u000a hydroformylation with a rhodium-triphenylphosphine catalyst, followed by hydrogenation. Rigid urethane foams prepared from\\u000a these hydroxymethylated derivatives had excellent compressive strengths, closed cell contents, and dimensional stability.\\u000a Best properties were obtained from hydroxymethylated polyol esters of castor acids.

C. K. Lyon; V. H. Garrett; E. N. Frankel

1974-01-01

326

Biodegradable thermogelling poly(ester urethane)s consisting of poly(lactic acid) – Thermodynamics of micellization and hydrolytic degradation  

Microsoft Academic Search

Multiblock poly(ether ester urethane)s comprising of poly(lactic acid) (PLA), poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) segments were synthesized, and their aqueous solutions exhibited thermogelling behavior at critical gelation concentrations (CGC) ranging from 7 to 9wt%. The chemical structures and molecular characteristics of the copolymers were studied by GPC, 1H NMR, 13C NMR and FTIR. The thermal stability of the

Xian Jun Loh; Yun Xuan Tan; Ziyun Li; Lin Shin Teo; Suat Hong Goh; Jun Li

2008-01-01

327

Ethyl arachidonate is the predominant fatty acid ethyl ester in the brains of alcohol-intoxicated subjects at autopsy  

Microsoft Academic Search

The role of fatty acid ethyl esters (FAEE), the nonoxidative ethanol metabolites, as mediators of alcohol-induced organ damage\\u000a is increasingly being recognized. FAEE are detectable in the blood and in liver and adipose tissue after ethanol ingestion,\\u000a and on that basis, FAEE can be used as markers of ethanol intake. In this study, 10 samples of human brain were collected

M. A. Refaai; P. N. Nguyen; J. E. Cluette-Brown; M. Laposata

2003-01-01

328

Human lysosomal acid lipase/cholesteryl ester hydrolase. Purification and properties of the form secreted by fibroblasts in microcarrier culture.  

PubMed

Lysosomal acid lipase was purified to near homogeneity in a yield of 25-30% from secretions of human fibroblasts grown on microcarriers in spinner culture. Ammonium chloride was added to the serum-free medium to stimulate production of extracellular enzyme and minimize modifications, including proteolytic processing and destruction of the mannose 6-phosphate recognition marker, that have been associated with packaging and maturation of acid hydrolases in lysosomes. Chromatography of secretions by decyl-agarose, hydroxylapatite, phenylboronate-agarose, and gel filtration resulted in greater than 1500-fold purification of the lipase, representing a 10,000-fold increase above the specific activity of intracellular enzyme. The apparent molecular weight of approximately 49,000, estimated for the lipase by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, was similar to that determined for the native enzyme by gel filtration (Mr approximately 47,000). By contrast, a smaller molecular weight (Mr approximately 41,000) was estimated for the intracellular enzyme. The purified enzyme was susceptible to hydrolysis by endo-beta-N-acetylglucosaminidase H, which resulted in at least two new forms, reduced in apparent molecular weight by approximately 4,000-6,000. Treatment with the endoglycosidase did not alter the catalytic activity or heat stability of the acid lipase. However, the treated enzyme was no longer internalized by fibroblasts via the mannose 6-phosphate receptor and thereby had lost the capacity to correct cholesteryl ester accumulation in cultured lipase-deficient cells. Acid fatty acyl hydrolase activity for cholesteryl oleate, triolein, and methylumbelliferyl oleate co-purified. All three esters were hydrolyzed optimally at pH 4.0, but the pH profile was altered by addition of salts or albumin to the phospholipid-bile salt substrate mixtures. In a series of saturated fatty acyl esters of 4-methylumbelliferone, a derivative with an intermediate chain length (9 carbons) was the best substrate and was hydrolyzed at a rate comparable to that of the oleate ester at pH 4. The optimal pH for hydrolysis of the intermediate and shorter chain length esters was higher by about 2 pH units than that for the longer chain esters (pH approximately 4). The activity of the purified lipase was stimulated by several different proteins. The relationship of this effect to the possible requirement for a natural activator substance has not been determined.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:4066668

Sando, G N; Rosenbaum, L M

1985-12-01

329

Synthesis, chemical and enzymatic hydrolysis, and bioavailability evaluation in rabbits of metronidazole amino acid ester prodrugs with enhanced water solubility.  

PubMed

A series of amino acid esters (3a-e) have been synthesized and evaluated as potential prodrugs of metronidazole with the aim of improving aqueous solubility and therapeutic efficacy. The aqueous solubility and the lipophilicity (expressed as the log P value) of metronidazole and its esters were investigated. In general the prodrugs revealed enhanced water solubility compared with metronidazole. N,N-diethylglycinate hydrochloride (3a) and 4-ethylpiperazinoacetate (3e) derivatives displayed higher aqueous solubility, which exceeded that of the parent drug by factors of approximately 140 and 100, respectively. All the esters revealed lower log P values than metronidazole except for the 4-phenylpiperazinoacetate derivative (3f), which was 6.5-times more lipophilic than metronidazole. The hydrolysis kinetics of the esters were studied in aqueous phosphate buffer (pH 7.4) and 80% human plasma at 37 degrees C. In all cases the hydrolysis followed pseudo-first-order kinetics and resulted in a quantitative reversion to metronidazole as evidenced by HPLC analysis. The prodrugs exhibited adequate chemical stability (half-life, t1/2, 4-16 h) in aqueous phosphate solution of pH 7.4. In 80% human plasma they were hydrolysed within a few minutesto metronidazole. The esters 3d (methylpiperazinoacetate derivative) and 3f were exempted since their t1/2 values were approximately 2.5 and 8.5 h, respectively. A comparative pH-rate profile study of N,N-diethylglycinate hydrochloride (3a) and 4-ethyl-piperazinoacetate (3e) derivatives in aqueous buffer solution over the pH range 2.2-10 was investigated. The results indicated that 3a showed marked stability at pH 2-6 followed by accelerated hydrolysis at pH 7.4. The basic ester 3e was found to be less stable at lower pH values but exhibited comparative stability at physiological pH. Moreover, in-vivo experiments in rabbits revealed a higher metronidazole plasma level with sustained release characteristics within the prodrug-treated animals (10- and 2.5-fold) as compared with the parent drug-treated group. In conclusion, the designed amino acid esters 3a and 3c-e might be considered as good candidates for water-soluble prodrug forms of metronidazole. PMID:11428660

Mahfouz, N M; Hassan, M A

2001-06-01

330

Acidic 1,3-propanediaminetetraacetato lanthanides with luminescent and catalytic ester hydrolysis properties  

NASA Astrophysics Data System (ADS)

In acidic solution, a serials of water-soluble coordination polymers (CPs) were isolated as zonal 1D-CPs 1,3-propanediaminetetraacetato lanthanides [Ln(1,3-H3pdta)(H2O)5]n·2Cln·3nH2O [Ln=La, 1; Ce, 2; Pr, 3; Nd, 4; Sm, 5] (1,3-H4pdta=1,3-propanediaminetetraacetic acid, C11H18N2O8) in high yields. When 1 eq. mol potassium hydroxide was added to the solutions of 1D-CPs, respectively, two 1D-CPs [Ln(1,3-H2pdta)(H2O)3]n·Cln·2nH2O [Ln=Sm, 6; Gd, 7] were isolated at room temperature and seven 2D-CPs [Ln(1,3-H2pdta)(H2O)2]n·Cln·2nH2O [Ln=La, 8; Ce, 9; Pr, 10; Nd, 11; Sm, 12; Eu, 13; Gd, 14] were isolated at 70 °C. When the crystals of 1-4 were hydrothermally heated at 180 °C with 1-2 eq. mol potassium hydroxide, four 3D-CPs [Ln(1,3-Hpdta)]n·nH2O [Ln=La, 15; Ce, 16; Pr, 17; Nd, 18] were obtained. The two 2D-CPs [Ln(1,3-Hpdta)(H2O)]n·4nH2O (Sm, 19; Eu, 20) were isolated in similar reaction conditions. With the increments of pH value in the solution and reaction temperature, the structure becomes more complicated. 1-5 are soluble in water and 1 was traced by solution 13C{1H} NMR technique, the water-soluble lanthanides 1 and 5 show catalytic activity to ester hydrolysis reaction respectively, which indicate their important roles in the hydrolytic reaction. The europium complexes 13 and 20 show visible fluorescence at an excitation of 394 nm. The structure diversity is mainly caused by the variation of coordinated ligand in different pH values and lanthanide contraction effect. Acidic conditions are favorable for the isolations of lanthanide complexes in different structures and this may helpful to separate different lanthanides. The thermal stability investigations reveal that acidic condition is favorable to obtain the oxides at a lower temperature.

Chen, Mao-Long; Shi, Yan-Ru; Yang, Yu-Chen; Zhou, Zhao-Hui

2014-11-01

331

Degradation of cyanidin-3-rutinoside and formation of protocatechuic acid methyl ester in methanol solution by gamma irradiation.  

PubMed

Anthocyanins are naturally occurring phenolic compounds having broad biological activities including anti-mutagenesis and anti-carcinogenesis. We studied the effects and the degradation mechanisms of the most common type of anthocyanins, cyanidin-3-rutinoside (cya-3-rut), by using gamma ray. Cya-3-rut in methanol (1mg/ml) was exposed to gamma-rays from 1 to 10kGy. We found that the reddish colour of cya-3-rut in methanol disappeared gradually in a dose-dependent manner and effectively disappeared (>97%) at 10kGy of gamma ray. Concomitantly, a new phenolic compound was generated and identified as a protocatechuic acid methyl ester by liquid chromatography, (1)H, and (13)C NMR. The formation of protocatechuic acid methyl ester increased with increasing irradiation and the amount of protocatechuic acid methyl ester formed by decomposition of cya-3-rut (20?g) at 10kGy of gamma ray was 1.95?g. In addition, the radical-scavenging activities were not affected by gamma irradiation. PMID:24629974

Lee, Seung Sik; Kim, Tae Hoon; Lee, Eun Mi; Lee, Min Hee; Lee, Ha Yeong; Chung, Byung Yeoup

2014-08-01

332

Potential cytoprotection: antioxidant defence by caffeic acid phenethyl ester against free radical-induced damage of lipids, DNA, and proteins.  

PubMed

Oxidative stress is considered to be a major cause of cellular injuries in a variety of chronic health problems, such as carcinogenesis and neurodegenerative disorders. Caffeic acid phenethyl ester (CAPE), derived from the propolis of honeybee hives, possesses a variety of biological and pharmacological properties including antioxidant and anticancer activity. In the present study, we focused on the diverse antioxidative functionalities of CAPE and its related polyphenolic acid esters on cellular macromolecules in vitro. The effects on human erythrocyte membrane ghost lipid peroxidation, plasmid pBR322 DNA, and protein damage initiated by the water-soluble initiator 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH) and hydrogen peroxide (H(2)O(2)) were monitored by formation of hydroperoxides and by DNA nicking assay, single-cell alkaline electrophoresis, and SDS-polyacrylamide gel electrophoresis. Our results showed that CAPE and its related polyphenolic acid esters elicited remarkable inhibitory effects on erythrocyte membrane lipid peroxidation, cellular DNA strand breakage, and protein fragmentation. The results suggest that CAPE is a potent exogenous cytoprotective and antigenotoxic agent against cell oxidative damage that could be used as a template for designing novel drugs to combat diseases induced by oxidative stress components, such as various types of cancer. PMID:18432289

Wang, Ting; Chen, Lixiang; Wu, Weimin; Long, Yuan; Wang, Rui

2008-05-01

333

Highly diastereofacial anti-aldol reaction: practical synthesis of optically active anti-2-alkyl-3-hydroxycarboxylic acid ester units.  

PubMed

A variety of esters derived from commercially available norephedrine were used in diastereoselective anti-aldol reactions. The aldol reaction of designed 2-(N-2-methylbenzyl-N-2,4,6-trimethylbenzyl)amino-1-phenylpropanol esters 4a-d with aldehydes furnished anti-2-alkyl-3-hydroxycarboxylic acid esters in excellent diastereomeric ratios (>98:2) when LDA-Cp2ZrCl2 (0.3 equiv) was used for enolization, followed by transmetalation into the zirconium enolate for aldolization. The novel auxiliary 3 for the anti-aldol reaction does not exhibit the ordinary basicity of tertiary amines; 3 can be extracted from acidic media with organic solvents. Its use is, therefore, very advantageous not only for extraction of the aldol products from the acidic water solutions, but also for recovering the chiral auxiliary 3 after the reductive cleavage. Treatment of aldol or 3-protected aldol products with DIBAL-H or LiAlH4 affords the versatile synthons, 2-alkyl-propane-1,3-diols or those 3-protected diols in >98% ee's together with 3 in nearly quantitative recovery. PMID:11312949

Kurosu, M; Lorca, M

2001-02-23

334

A convenient asymmetric synthesis of a beta-amino ester with additional functionalization as a precursor for peptide nucleic acid (PNA) monomers.  

PubMed

We report the asymmetric synthesis of di-3-pentyl (3S,alphaS,7E)-3-N-benzyl-N-alpha-methylbenzylamino-dec-7-enedioate (9), which contains the correct functionalization to produce delta-amino acid derivatives to be used as monomers for Peptide Nucleic Acid (PNA) formation With this aim, thymine-pentanoic acid 15 and some of its ester derivatives were obtained, their reactivity was studied and the noteworthy ethyl ester 12 was quantitatively produced by transesterification of methyl ester 11, thus paving the way for the synthesis of the thymine-containing amino ester IV, which has been designed as a building block for a Nucleic-Acid analog with a chiral, flexible peptide backbone. PMID:17962776

Garrido, Narciso M; Díez, David; Domínguez, Sara H; Sánchez, M Rosa; García, Mercedes; Urones, Julio G

2006-01-01

335

Surfactants from biomass: a two-step cascade reaction for the synthesis of sorbitol fatty acid esters using solid acid catalysts.  

PubMed

Sorbitol fatty esters have been prepared through a two-step catalytic process which involves the protection of the polyalcohol by ketalization followed by esterification with the fatty acid. Inorganic molecular sieves with different pore topologies as well as heteropolyacids (HPA) were used as acid catalysts to perform both the ketalization and the esterification step. These catalysts are found to hydrolyze the ketal function and promote the esterification between the free hydroxy groups and oleic acid in a cascade process. The results show a positive shape-selectivity effect when the process is carried out using tridirectional, and especially monodirectional (mordenite), zeolites, such that the ratio of mono- to higher esters and the hydroxy number of the final product are increased as compared to those obtained for the homogeneous-catalyzed process. PMID:18605669

Corma, Avelino; Hamid, Sharifah B A; Iborra, Sara; Velty, Alexandra

2008-01-01

336

Contribution to the analysis of the essential oil of Helichrysum italicum (Roth) G. Don. Determination of ester bonded acids and phenols.  

PubMed

The essential oil of Helichrysum italicum (Roth) G. Don (everlasting or Immortelle essential oil) was isolated by hydrodistillation and analysed by GC and GCMS. Forty four compounds were identified. The main components were alpha-pinene(12.8%), 2-methyl-cyclohexyl pentanoate (11.1 %), neryl acetate (10.4%), 1,7-di-epi-alpha-cedrene (6.8%) and other compounds. The oil was fractionated and ester-containing fraction was hydrolysed with KOH/H(2)SO(4). The liberated volatiles were analysed by GC and GC-MS: three phenols and twenty seven volatile carboxylic acids were identified[70% low fatty acids (C(2)-C(5)), 15% C(10)-C(12) acids and 15% other acids]. The main acids were acetic acid (24.3%) propanoic acid (17.2%), 2-methylpropanoic acid (11.4%),dodecanoic acid (8.7%), 2-methylbutanoic acid (8.3%), (Z)-2-methylbutenoic acid(5.1%) and decanoic acid (4.6%). With respect to the identified bonded carboxylic acids,the minimal number of esters in the oil was twenty seven, but their overall quantity was probably larger due to different possible combinations of alcohols with acids to form esters. On the other hand, only six main esters were identified in the oil before fractionation and hydrolysis. PMID:18463581

Masteli?, Josip; Politeo, Olivera; Jerkovi?, Igor

2008-01-01

337

Intestinal absorption and biliary elimination of glycyrrhizic acid diethyl ester in rats  

PubMed Central

Background The purpose of this study was to evaluate absorption and elimination from the gastrointestinal tract of glycyrrhizic acid diethyl ester (GZ-DE) which was prepared as a prodrug of glycyrrhizic acid (a poorly absorbed compound) in rats. Methods After the GZ-DE solution was administered via the intravenous, intraduodenal, intraileal, and stomach routes, GZ-DE and GZ concentrations in bile were determined by high-performance liquid chromatography. The stability of GZ-DE was estimated from residual GZ-DE and GZ produced in GZ-DE solutions prepared with distilled water, a pH 1.2 solution, 0.9% NaCl solution, and phosphate-buffered solution (pH 7.4) at 37°C. Results GZ-DE was eliminated into bile by the pharmacokinetic parameters of apparent distribution rate constant (4.56 ± 0.36 per hour) and apparent elimination rate constant (0.245 ± 0.042 per hour). After intravenous and intraduodenal administration of GZ-DE, the concentration ratio of GZ-DE to GZ in bile was approximately 4:1, and the bioavailability of GZ containing GZ-DE was three-fold higher compared with the bioavailability of GZ after intraduodenal administration. GZ-DE was immediately precipitated in pH 1.2 solution and was converted to GZ by hydrolysis in pH 7.4 solution. Conclusion Improvement of intestinal absorption of GZ was made possible by administration of GZ-DE into the intestine where absorption of GZ is lower than in the strong acidic environment of the stomach. However, because the elimination rate in bile simulated from kinetic parameters of GZ-DE was higher than the conversion rate from GZ-DE to GZ by hydrolysis, it is thought that the availability of GZ as a revolutionary prodrug was not high from the viewpoint of bioavailability of GZ in the liver by intestinal administration of GZ-DE. PMID:24174868

Koga, Kenjiro; Kawamura, Mayuri; Iwase, Hiroshi; Yoshikawa, Nobuji

2013-01-01

338

Production of Fatty Acid Methyl Esters via the In Situ Transesterification of Soybean Oil in Carbon Dioxide-Expanded Methanol  

Microsoft Academic Search

The production of fatty acid methyl esters (FAME) by direct alkali- and acid-catalyzed in situ transesterification of soybean\\u000a flakes in CO2-expanded methanol was examined at various temperatures and pressures. Attempts to synthesize FAME from soy flakes via alkaline\\u000a catalysis, using sodium methoxide as a catalyst, in gas-expanded methanol were unsuccessful. However, performing the reactions\\u000a in 54 mL of a 1.2 N sulfuric

Victor T. Wyatt; Michael J. Haas

2009-01-01

339

Tallow based detergent formulations: Mixtures of alcohol sulfates, salts of a -sulfo acids and esters, and soap  

Microsoft Academic Search

Saturated (I, ROSO3Na) and unsaturated (II, R’OSO3Na) tallow alcohol sulfates, the disodium salt ofa-sulfonated saturated tallow fatty acids (III, RCH(SO3Na)CO2Na), the sodium salt of the methyl ester ofa-sulfonated saturated tallow fatty acids (IV, RCH(SO3Na) CO2CH3), and commercial tallow soap flakes (V) were compared, singly and in combinations, as built and unbuilt solutions in soft\\u000a and hard water, with respect to

A. J. Stirton; R. G. Bistline; Eileen B. Leardi; M. V. Nuñez-Ponzoa

1967-01-01

340

Mechanisms of Oxidative Damage in Multiple Sclerosis and Neurodegenerative Diseases: Therapeutic Modulation via Fumaric Acid Esters.  

PubMed

Oxidative stress plays a crucial role in many neurodegenerative conditions such as Alzheimer's disease, amyotrophic lateral sclerosis and Parkinson's as well as Huntington's disease. Inflammation and oxidative stress are also thought to promote tissue damage in multiple sclerosis (MS). Recent data point at an important role of anti-oxidative pathways for tissue protection in chronic-progressive MS, particularly involving the transcription factor nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2). Thus, novel therapeutics enhancing cellular resistance to free radicals could prove useful for MS treatment. Here, fumaric acid esters (FAE) are a new, orally available treatment option which had already been tested in phase II/III MS trials demonstrating beneficial effects on relapse rates and magnetic resonance imaging markers. In vitro, application of dimethylfumarate (DMF) leads to stabilization of Nrf2, activation of Nrf2-dependent transcriptional activity and abundant synthesis of detoxifying proteins. Furthermore, application of FAE involves direct modification of the inhibitor of Nrf2, Kelch-like ECH-associated protein 1. On cellular levels, the application of FAE enhances neuronal survival and protects astrocytes against oxidative stress. Increased levels of Nrf2 are detected in the central nervous system of DMF treated mice suffering from experimental autoimmune encephalomyelitis (EAE), an animal model of MS. In EAE, DMF ameliorates the disease course and improves preservation of myelin, axons and neurons. Finally, Nrf2 is also up-regulated in the spinal cord of autopsy specimens from untreated patients with MS, probably as part of a naturally occurring anti-oxidative response. In summary, oxidative stress and anti-oxidative pathways are important players in MS pathophysiology and constitute a promising target for future MS therapies like FAE. PMID:23109883

Lee, De-Hyung; Gold, Ralf; Linker, Ralf A

2012-01-01

341

Identification of differential proteins in colorectal cancer cells treated with caffeic acid phenethyl ester  

PubMed Central

AIM: To investigate the molecular mechanisms of the anti-cancer activity of caffeic acid phenethyl ester (CAPE). METHODS: Protein profiles of human colorectal cancer SW480 cells treated with or without CAPE were analysed using a two-dimensional (2D) electrophoresis gel-based proteomics approach. After electrophoresis, the gels were stained with Coomassie brilliant blue R-250. Digital images were taken with a GS-800 Calibrated Densitometer, and image analysis was performed using PDQuest 2-D Analysis software. The altered proteins following CAPE treatment were further identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry following a database search. The identified proteins were validated by Western blot and immunofluorescence assay. RESULTS: CAPE induced human colorectal cancer cell apoptosis. Four up-regulated proteins and seven down-regulated proteins in colorectal cancer cells treated with CAPE were found. The identified down-regulated proteins in CAPE-treated colorectal cancer cells were Triosephosphate Isomerase (Tim), Proteasome subunit alpha 4 (PSMA4) protein, Guanine nucleotide binding protein beta, Phosphoserine aminotransferase 1 (PSAT1), PSMA1, Myosin XVIIIB and Tryptophanyl-tRNA synthetase. Notably, CAPE treatment led to the down-regulation of PSAT1 and PSMA1, two proteins that have been implicated in tumorigenesis. The identified up-regulated proteins were Annexin A4, glyceraldehyde-3-phosphate dehydrogenase, Glucosamine-6-phosphate deaminase 1 (GNPDA1), and Glutathione peroxidase (GPX-1). Based on high match scores and potential role in cell growth control, PSMA1, PSAT1, GNPDA1 and GPX-1 were further validated by Western blotting and immunofluorescence assay. PSMA1 and PSAT1 were down-regulated, while GNPDA1 and GPX-1 were up-regulated in CAPE-treated colorectal cancer cells. CONCLUSION: These differentiated proteins in colorectal cancer cells following CAPE treatment, may be potential molecular targets of CAPE and involved in the anti-cancer effect of CAPE. PMID:25206290

He, Yu-Jun; Li, Wan-Ling; Liu, Bao-Hua; Dong, Hui; Mou, Zhi-Rong; Wu, Yu-Zhang

2014-01-01

342

Caffeic acid phenethyl ester decreases acute pneumonitis after irradiation in vitro and in vivo  

PubMed Central

Background Lung cancer is relatively resistant to radiation treatment and radiation pneumonitis is a major obstacle to increasing the radiation dose. We previously showed that Caffeic acid phenethyl ester (CAPE) induces apoptosis and increases radiosensitivity in lung cancer. To determine whether CAPE, an antioxidant and an inhibitor of NF-kappa B, could be a useful adjuvant agent for lung cancer treatment, we examine the effects of CAPE on irradiated normal lung tissue in this study. Methods We compared the effects of CAPE on cytotoxicity and intracellular oxidative stress in normal lung fibroblast and a lung cancer cell line. For in vivo analysis, whole thorax radiation (single dose 10 Gy and 20 Gy) was delivered to BALB/c male mice with or without CAPE pretreatment. NF- kappaB activation and the expression levels of acute inflammatory cytokines were evaluated in mice after irradiation. Results The in vitro studies showed that CAPE cause no significant cytotoxicity in normal lung as compared to lung cancer cells. This is probably due to the differential effect on the expression of NF-kappa B between normal and malignant lung cells. The results from in vivo study showed that CAPE treatment decreased the expression of inflammatory cytokines including IL-1 alpha and beta, IL-6, TNF-alpha and TGF- beta, after irradiation. Moreover, histological and immunochemical data revealed that CAPE decreased radiation- induced interstitial pneumonitis and TGF-beta expression. Conclusion This study suggests that CAPE decreases the cascade of inflammatory responses induced by thoracic irradiation without causing toxicity in normal lung tissue. This provides a rationale for combining CAPE and thoracic radiotherapy for lung cancer treatment in further clinical studies. PMID:16336675

Chen, Miao-Fen; Keng, Peter C; Lin, Paul-Yang; Yang, Cheng-Ta; Liao, Shuen-Kuei; Chen, Wen-Cheng

2005-01-01

343

Phase behavior of diglycerol fatty acid esters-nonpolar oil systems.  

PubMed

Phase behavior of diglycerol fatty acid esters (Qn-D, where n represents the carbon number in the alkyl chain length of amphiphile, n = 10-16) were investigated in different nonpolar oils, liquid paraffin (LP70), squalane, and squalene. There is surfactant solid at lower temperature, and the surfactant solid does not swell in oil, and the melting temperature is almost constant in a wide range of compositions. In all of the systems, a lamellar liquid crystal (L(alpha)) is formed in a concentrated region at a temperature between the solid melting temperature and the isotropic two- or single-phase regions. In the dilute regions, reverse vesicles are formed in L(alpha) + O regions. There are two liquid-phase regions above the L(alpha) present region. This two-phase boundary corresponds to the cloud-point curve of nonionic surfactant aqueous solutions. However, instead of being less soluble in water at high temperature for the cloud point, the surfactant becomes more soluble in the organic solvents at high temperature. Namely, the effect of temperature on the solubility is opposite to the clouding phenomenon. When the hydrocarbon chain of the diglycerol surfactant decreases, the two-phase region becomes wider. In the case of a fixed surfactant, the surfactant is most miscible with squalene (narrowest two-phase regions) and the order of dissolutions tendency is squalene > LP70 > squalane. These results show that the hydrophilic moiety (diglycerol group) is more insoluble in oil compared with that of a conventional poly(oxyethylene)-type nonionic surfactant. Formation of reversed rodlike micelles was confirmed by SAXS scattering curve. When the hydrocarbon chain of surfactant is short, the micellar size becomes larger. In a fixed surfactant system, the reverse micellar size increases by changing oil from squalene to LP70. A small amount of water induces a dramatic elongation of reverse micelles. PMID:16460060

Shrestha, Lok Kumar; Kaneko, Masaya; Sato, Takaaki; Acharya, Durga P; Iwanaga, Tetsuro; Kunieda, Hironobu

2006-02-14

344

Effects of Potamogeton crispus L. on the fate of phthalic acid esters in an aquatic microcosm.  

PubMed

To study the effects of submerged hydrophytes on the fate of dibutyl phthalate (DBP) and di-2-ethylexyl phthalate (DEHP) in the aquatic environment, a Potamogeton crispus L. (P. crispus) microcosm was constructed. A four-compartment (i.e., water, plant, non-rhizosphere and rhizosphere sediments) level IV fugacity model was established and applied to the simulation experiments in the microcosm. Data obtained from model calculations were in good agreement with those from the experiments. Results of the model calculations showed that the total residues of DBP and DEHP in the microcosm with P. crispus were 39.7% and 19.8% lower than those in the microcosm without P. crispus. The overall biodegradation fluxes of DBP and DEHP in the microcosm with P. crispus increased by 4.7% and 12.3%, respectively, and meanwhile, advective outflow decreased. In the presence of P. crispus, a large fraction of loaded DBP and DEHP (17.7% and 29.0%) transferred to plants, and then to the rhizosphere. 4.8% and 28.0% of loaded DBP and DEHP were removed by biodegradation in P. crispus, and the remaining 12.9% and 1.0% were by biodegradation in rhizosphere sediment which was 3.6% of the total sediment. This finding demonstrates that P. crispus can substantially reduce the accumulation of phthalic acid esters (PAEs) in the experiment system and enhance the removal of PAEs. The enhancement of PAE removal is related to the biodegradation of PAEs in P. crispus, especially for the more hydrophobic DEHP. For the less hydrophobic DBP, biodegradation in the rhizosphere also plays a key role. In addition to nutrient uptake from sediment, transport process between P. crispus and the rhizosphere has also a significant influence on the distribution and fate of PAEs in the aquatic environment. PMID:22405677

Chi, Jie; Yang, Qing

2012-05-15

345

Examination of sex differences in fatty acid ethyl ester and ethyl glucuronide hair analysis.  

PubMed

Clinical studies examining performance of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in identifying excessive alcohol consumption have been primarily conducted in male populations. An impact of hair cosmetics in producing both false-negative EtG results and false-positive FAEE results has been demonstrated, suggesting a possible bias in female populations. This study evaluates FAEE-positive hair samples (>0.50?ng/mg) from n?=?199 female and n?=?73 male subjects for EtG. Higher FAEE/EtG concordance was observed amongst male over female subjects. Performance of multiple proposed EtG cut-off levels were assessed; amongst female samples, FAEE/EtG concordance was 36.2% (30?pg/mg), 36.7% (27?pg/mg), and 43.7% (20?pg/mg). Non-coloured hair demonstrated a two-fold increase in concordance (41.8 v. 20.8%) over coloured hair in the female cohort. FAEE levels did not differ between male and female subjects; however they were lower in coloured samples (p?=?0.046). EtG was lower in female subjects (p?=?0.019) and coloured samples (p?=?0.026). A total of n?=?111 female samples were discordant. Amongst discordant samples (EtG-negative), 26% had evidence of recent alcohol use including consultation histories (n?=?20) and detectable cocaethylene (n?=?9); 29% of discordant samples were coloured. False-negative risk with ethyl glucuronide analysis in females was mediated by cosmetic colouring. These findings suggest that combined analysis of FAEE and EtG is optimal when assessing a female population and an EtG cut-off of 20?pg/mg is warranted when using combined analysis. While concordant FAEE/EtG-positive findings constitute clear evidence, discordant FAEE/EtG findings should still be considered suggestive evidence of chronic excessive alcohol consumption. PMID:24817046

Gareri, Joey; Rao, Chitra; Koren, Gideon

2014-06-01

346

Caffeic Acid Phenethyl Ester Protects against Amphotericin B Induced Nephrotoxicity in Rat Model  

PubMed Central

The present study was conducted to investigate whether caffeic acid phenethyl ester (CAPE), an active component of propolis extract, has a protective effect on amphotericin B induced nephrotoxicity in rat models. Male Wistar-Albino rats were randomly divided into four groups: (I) control group (n = 10), (II) CAPE group (n = 9) which received 10??mol/kg CAPE intraperitoneally (i.p.), (III) amphotericin B group (n = 7) which received one dose of 50?mg/kg amphotericin B, and (IV) amphotericin B plus CAPE group (n = 7) which received 10??mol/kg CAPE i.p. and one dose of 50?mg/kg amphotericin B. The left kidney was evaluated histopathologically for nephrotoxicity. Levels of malondialdehyde (MDA), nitric oxide (NO), enzyme activities including catalase (CAT), and superoxide dismutase (SOD) were measured in the right kidney. Histopathological damage was prominent in the amphotericin B group compared to controls, and the severity of damage was lowered by CAPE administration. The activity of SOD, MDA, and NO levels increased and catalase activity decreased in the amphotericin B group compared to the control group (P = 0.0001, P = 0.003, P = 0.0001, and P = 0.0001, resp.). Amphotericin B plus CAPE treatment caused a significant decrease in MDA, NO levels, and SOD activity (P = 0.04, P = 0.02, and P = 0.0001, resp.) and caused an increase in CAT activity compared with amphotericin B treatment alone (P = 0.005). CAPE treatment seems to be an effective adjuvant agent for the prevention of amphotericin B nephrotoxicity in rat models. PMID:25032223

Altuntas, Atila; Y?lmaz, H. Ramazan; Altuntas, Aysegul; Uz, Efkan; Demir, Murat; Gokcimen, Alparslan; Aksu, Oguzhan; Bayram, Dilek Senol; Sezer, Mehmet Tugrul

2014-01-01

347

Phthalic Acid Esters in Soils from Vegetable Greenhouses in Shandong Peninsula, East China  

PubMed Central

Soils at depths of 0 cm to 10 cm, 10 cm to 20 cm, and 20 cm to 40 cm from 37 vegetable greenhouses in Shandong Peninsula, East China, were collected, and 16 phthalic acid esters (PAEs) were detected using gas chromatography-mass spectrometry (GC-MS). All 16 PAEs could be detected in soils from vegetable greenhouses. The total of 16 PAEs (?16PAEs) ranged from 1.939 mg/kg to 35.442 mg/kg, with an average of 6.748 mg/kg. Among four areas, including Qingdao, Weihai, Weifang, and Yantai, the average and maximum concentrations of ?16PAEs in soils at depths of 0 cm to 10 cm appeared in Weifang, which has a long history of vegetable production and is famous for extensive greenhouse cultivation. Despite the different concentrations of ?16PAEs, the PAE compositions were comparable. Among the 16 PAEs, di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DnOP), di-n-butyl phthalate (DnBP), and diisobutyl phthalate (DiBP) were the most abundant. Compared with the results on agricultural soils in China, soils that are being used or were used for vegetable greenhouses had higher PAE concentrations. Among PAEs, dimethyl phthalate (DMP), diethyl phthalate (DEP) and DnBP exceeded soil allowable concentrations (in US) in more than 90% of the samples, and DnOP in more than 20%. Shandong Peninsula has the highest PAE contents, which suggests that this area is severely contaminated by PAEs. PMID:24747982

Chai, Chao; Cheng, Hongzhen; Ge, Wei; Ma, Dong; Shi, Yanxi

2014-01-01

348

Effects of caffeic acid phenethyl ester on palatal mucosal defects and tooth extraction sockets  

PubMed Central

Aim The purpose of this study was to evaluate the effects of caffeic acid phenethyl ester (CAPE) on palatal mucosal defects and tooth extraction sockets in an experimental model. Materials and methods Forty-two male Sprague-Dawley rats with a mean age of 7 weeks and weighing 280–490 g were used in this study. The rats were randomly divided into two groups: group A (the control group, n=21) and group B (the experimental group, n=21). Under anesthesia with ketamine (8 mg/100 g, intraperitoneally), palatal mucosal defects were created and tooth extraction was performed in the rats in groups A and B. Group A received no treatment, whereas group B received CAPE. CAPE was injected daily (10 ?mol/kg, intraperitoneally). The rats were killed on days 7, 14, and 30 after the procedures. Palatal mucosa healing and changes in bone tissue and fibrous tissue were evaluated histopathologically. Result Pairwise comparisons showed no statistically significant difference between days 7 and 14 in either group (P>0.05). At day 30, bone healing was significantly better in group B (CAPE) than in group A (control) (P<0.05). Fibrinogen levels at day 30 were significantly higher in group A (control) than in group B (CAPE) (P<0.05). Pairwise comparisons showed no statistically significant difference in palatal mucosa healing levels between days 7 and 14 in both groups (P>0.05). Conclusion In conclusion, the findings of this study suggest that CAPE can significantly improve tooth socket healing. PMID:25364232

Gunay, Ahmet; Arpag, Osman Fatih; Atilgan, Serhat; Yaman, Ferhan; Atalay, Yusuf; Acikan, Izzet

2014-01-01

349

Mechanisms of Oxidative Damage in Multiple Sclerosis and Neurodegenerative Diseases: Therapeutic Modulation via Fumaric Acid Esters  

PubMed Central

Oxidative stress plays a crucial role in many neurodegenerative conditions such as Alzheimer’s disease, amyotrophic lateral sclerosis and Parkinson’s as well as Huntington’s disease. Inflammation and oxidative stress are also thought to promote tissue damage in multiple sclerosis (MS). Recent data point at an important role of anti-oxidative pathways for tissue protection in chronic-progressive MS, particularly involving the transcription factor nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2). Thus, novel therapeutics enhancing cellular resistance to free radicals could prove useful for MS treatment. Here, fumaric acid esters (FAE) are a new, orally available treatment option which had already been tested in phase II/III MS trials demonstrating beneficial effects on relapse rates and magnetic resonance imaging markers. In vitro, application of dimethylfumarate (DMF) leads to stabilization of Nrf2, activation of Nrf2-dependent transcriptional activity and abundant synthesis of detoxifying proteins. Furthermore, application of FAE involves direct modification of the inhibitor of Nrf2, Kelch-like ECH-associated protein 1. On cellular levels, the application of FAE enhances neuronal survival and protects astrocytes against oxidative stress. Increased levels of Nrf2 are detected in the central nervous system of DMF treated mice suffering from experimental autoimmune encephalomyelitis (EAE), an animal model of MS. In EAE, DMF ameliorates the disease course and improves preservation of myelin, axons and neurons. Finally, Nrf2 is also up-regulated in the spinal cord of autopsy specimens from untreated patients with MS, probably as part of a naturally occurring anti-oxidative response. In summary, oxidative stress and anti-oxidative pathways are important players in MS pathophysiology and constitute a promising target for future MS therapies like FAE. PMID:23109883

Lee, De-Hyung; Gold, Ralf; Linker, Ralf A.

2012-01-01

350

Concise asymmetric synthesis of a (1R,2S)-1-amino- 2-vinylcyclopropanecarboxylic acid-derived sulfonamide and ethyl ester.  

PubMed

The development and demonstration of short, robust and chromatography-free sequences for the preparation of a (1R,2S)-1-amino-2-vinylcyclopropane-carboxylic acid-derived sulfonamide and ethyl ester in ?99% ee are described. Both compounds are common building blocks in multiple preparations of potent HCV NS3 protease inhibitors. The robustness of the asymmetric cyclopropanation of (E)-N-benzylideneglycine ethyl ester under phase transfer catalysis conditions is significantly improved based on a detailed mechanistic investigation that included an analysis of the catalyst decomposition pathway, a postulated model for the stereo-selectivity that was guided by calculations and rigorous quality control of the starting materials and reagents. Wet milling has been demonstrated to dramatically accelerate this phase transfer reaction. A bench stable benzylidene-protected primary 1-amino-2-vinylcyclopropane amide intermediate was isolated and its reliable enantiomeric enrichment was achieved by a controlled crystallization process. A chemical resolution procedure was identified using di-p-toluoyl-(D)-tartaric acid to access (1R,2S)-1-amino-2-vinyl-cyclopropanecarboxylic ester in high ee. PMID:24175327

Lou, Sha; Cuniere, Nicolas; Su, Bao-Ning; Hobson, Lindsay A

2013-10-21

351

Pharmacokinetics of amino acid ester prodrugs of acyclovir after oral administration: interaction with the transporters on Caco-2 cells.  

PubMed

In vivo systemic absorption of the amino acid prodrugs of acyclovir (ACV) after oral administration was evaluated in rats. Stability of the prodrugs, L-alanine-ACV (AACV), L-serine-ACV (SACV), L-isoleucine-ACV (IACV), gamma-glutamate-ACV (EACV) and L-valine-ACV (VACV) was evaluated in various tissues. Interaction of these prodrugs with the transporters on Caco-2 cells was studied. In vivo systemic bioavailability of these prodrugs upon oral administration was evaluated in jugular vein cannulated rats. The amino acid ester prodrugs showed affinity towards various amino acid transporters as well as the peptide transporter on the Caco-2 cells. In terms of stability, EACV was most enzymatically stable compared to other prodrugs especially in liver homogenate. In oral absorption studies, ACV and AACV showed high terminal elimination rate constants (lambda(z)). SACV and VACV exhibited approximately five-fold increase in area under the curve (AUC) values relative to ACV (p<0.05). C(max(T)) (maximum concentration) of SACV was observed to be 39+/-22 microM in plasma which is 2 times better than VACV and 15 times better than ACV. C(last(T)) (concentration at the last time point) of SACV was observed to be 0.18+/-0.06 microM in plasma which is two times better than VACV and three times better than ACV. Amino acid ester prodrugs of ACV were absorbed at varying amounts (C(max)) and eliminated at varying rates (lambda(z)) thereby leading to varying extents (AUC). The amino acid ester prodrug SACV owing to its enhanced stability, higher AUC and better concentration at last time point seems to be a promising candidate for the oral treatment of herpes infections. PMID:18638532

Katragadda, Suresh; Jain, Ritesh; Kwatra, Deep; Hariharan, Sudharshan; Mitra, Ashim K

2008-10-01

352

Caffeic Acid Phenethyl Ester as a Protective Agent against Nephrotoxicity and/or Oxidative Kidney Damage: A Detailed Systematic Review  

PubMed Central

Caffeic acid phenethyl ester (CAPE), an active component of propolis, has been attracting the attention of different medical and pharmaceutical disciplines in recent years because of its antioxidant, anti-inflammatory, antiproliferative, cytotoxic, antiviral, antifungal, and antineoplastic properties. One of the most studied organs for the effects of CAPE is the kidney, particularly in the capacity of this ester to decrease the nephrotoxicity induced by several drugs and the oxidative injury after ischemia/reperfusion (I/R). In this review, we summarized and critically evaluated the current knowledge regarding the protective effect of CAPE in nephrotoxicity induced by several special medicines such as cisplatin, doxorubicin, cyclosporine, gentamycin, methotrexate, and other causes leading to oxidative renal injury, namely, I/R models and senility. PMID:25003138

Akyol, Sumeyya; Ugurcu, Veli; Altuntas, Aynur; Hasgul, Rukiye; Cakmak, Ozlem

2014-01-01

353

Induction of apoptosis by a potent caffeic acid derivative, caffeic acid undecyl ester, is mediated by mitochondrial damage in NALM-6 human B cell leukemia cells  

PubMed Central

Caffeic acid esters have various biological activities, and we previously reported that undecyl caffeate (caffeic acid undecyl ester, CAUE), a new caffeic acid derivative, has strong pharmacological activity. The present study investigated the cytotoxicity of both CAUE and its parent compound, caffeic acid phenethyl ester (CAPE), and characterized the mechanisms by which they induce apoptosis in the human B cell leukemia cell line NALM-6. Treatment with CAUE reduced cell survival in NALM-6 cells but had no significant effect on the survival of normal lymphocytes. When assessing the 50% inhibitory concentration (IC50) for cytotoxicity, CAUE had 10-fold higher activity than CAPE in NALM-6 cells. CAUE treatment resulted in induction of apoptotic features in NALM-6 cells, including cleaved poly (ADP-ribose) polymerase and activated caspase-3. A caspase inhibitor completely blocked CAUE-induced apoptosis. CAUE treatment resulted in a concentration- and time-dependent decrease in both mitochondrial membrane potential and downregulation of Bcl-2 expression. Moreover, CAUE-induced apoptosis was enhanced in the Bcl-2 knockdown condition induced by small interfering RNA. These data suggest that CAUE-induced apoptosis was mediated via an apoptotic intrinsic pathway including mitochondrial damage and was caspase-dependent. These data also suggest that CAUE is a powerful anti-leukemic agent that acts via induction of apoptosis by mitochondrial damage and selective action in leukemia cells. PMID:23229564

TOMIZAWA, AYAKO; KANNO, SYU-ICHI; OSANAI, YUU; GOTO, AKANE; SATO, CHIZURU; YOMOGIDA, SHIN; ISHIKAWA, MASAAKI

2013-01-01

354

40 CFR 721.5375 - Ni-tro-thio-phene-car-boxy-lic acid, ethyl es-ter, bis-[[[[(sub-sti-tut-ed)] amino]-alkyl-phenyl...  

Code of Federal Regulations, 2010 CFR

...Ni-tro-thio-phene-car-boxy-lic acid, ethyl es-ter...sub-sti-tut-ed)] amino]-alkyl-phenyl...Ni-tro-thio-phene-car-boxy-lic acid, ethyl es-ter...sub-sti-tut-ed)] amino]-alkyl-phenyl...ni-tro-thio-phene-car-boxy-lic acid, ethyl ester,...

2010-07-01

355

Understanding hypertriglyceridemia in women: clinical impact and management with prescription omega-3-acid ethyl esters  

PubMed Central

Background: Elevated triglycerides (TGs) are a common lipid disorder in the US and are associated with comorbidities such as pancreatitis, obesity, type 2 diabetes, and metabolic syndrome. TGs are generally elevated in postmenopausal women compared with premenopausal women. Meta-analysis has shown that elevated TGs are associated with an increased risk of coronary heart disease (CHD). Objective: This article provides a general overview of TG metabolism and reviews data on the epidemiology and risk of elevated TGs in women, as pregnancy and menopause, in particular, have been associated with unfavorable changes in the lipoprotein profile, including elevations in TGs. In addition, this review seeks to explain the recommended TG goals and treatment options for hypertriglyceridemia with an emphasis on severe hypertriglyceridemia (TGs ? 500 mg/dL) and its respective treatment with prescription omega-3-acid ethyl esters (P-OM3). Methods: MedLine was searched for articles published through August 2009 using the terms “hypertriglyceridemia” and “dyslipidemia”, with subheadings for “prevalence”, “women”, “treatment”, “guidelines”, “risk”, and “omega-3 fatty acids”. Publications discussing the epidemiology of hypertriglyceridemia, CHD risk, treatment guidelines for lipid management, or clinical trials involving P-OM3 were selected for review. The reference lists of relevant articles were also examined for additional citations. Results: Hypertriglyceridemia is associated with increased CHD risk. Women, especially those with polycystic ovarian syndrome, type 2 diabetes, or who are postmenopausal, should be monitored regularly for the impact of hypertriglyceridemia on their lipid profile. Cardiovascular risk of TGs can be indirectly assessed by monitoring non-high-density lipoprotein cholesterol (non-HDL-C) levels. There are multiple sets of guidelines providing recommendations for desirable low-density lipoprotein cholesterol, TG, and non-HDL-C levels. Treatment of hypertriglyceridemia includes lifestyle interventions and, if needed, pharmacologic therapy. In patients with severe hypertriglyceridemia, P-OM3 can reduce TGs by up to 45%. Conclusion: Physicians should regularly monitor the lipid profile of their female patients. Any lipid abnormality should be managed promptly according to established guidelines. P-OM3 provide a well-tolerated option for the treatment of severe hypertriglyceridemia. PMID:21445284

Dayspring, Thomas D

2011-01-01

356

EXTRACTION OF RARE EARTH METALS WITH 2-ETHYLHEXYL PHOSPHONIC ACID MONO2-ETHYLHEXYL ESTER IN THE PRESENCE OF DIETHYLENETRIAMINEPENTAACETIC ACID IN AQUEOUS PHASE  

Microsoft Academic Search

The extraction equilibria of rare earth metals with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (commercial name, PC-88A, henceforth abbreviated as HR) dissolved in n-heptane were measured at 303 K. It was found that rare earth metals are extracted with the dimer of the extractant, (HR)2, as follows.The extraction equilibrium constants of metals were obtained and compared with the extraction equilibrium constants

Fukiko Kubota; Masahiro Goto; Fumiyuki Nakashio

1993-01-01

357

Enantioselectivity of Candida rugosa lipases (Lip1, Lip3, and Lip4) towards 2-bromo phenylacetic acid octyl esters controlled by a single amino acid.  

PubMed

Enantiomer discrimination by enzymes is a very accurate mechanism, which often involves few amino acids located at the active site. Lipase isoforms from Candida rugosa are very good enzymatic models to study this phenomenon as they display high sequence homology (>80%) and their enantioselectivity is often pointed out. In the present work, we investigated three lipases from C. rugosa (Lip1, Lip3, and Lip4, respectively) towards the resolution of 2-bromo-arylacetic acid esters, an important class of chemical intermediates in the pharmaceutical industry. All exhibited a high enantioselectivity, with Lip4 preferring the R-enantiomer (E-value = 15), while Lip1 and Lip3 showed an S-enantioselectivity >200. A combination of sequence and structure analysis of the three C. rugosa lipases suggested that position 296 could play a role in S- or R-enantiomer preference of C. rugosa lipases. This led to the construction by site-directed mutagenesis of Lip1 and Lip4 variants in which position 296 was, respectively, exchanged by a Gly, Ala, Leu, or Phe amino acid. Screening of these variants for their enantioselectivity toward 2-bromo phenyl acetic acid octyl esters revealed that steric hindrance of the amino acid residue introduced at position 296 controls both the enantiopreference and the enantioselectivity value of the lipase: bulkier is the amino acid at position 296, larger is the selectivity towards the S-enantiomer. To investigate further these observations at an atomic level, we carried out a preliminary modeling study of the tetrahedral intermediates formed by Lip1 and Lip4 with the (R, S)-2-bromo-phenylacetic acid octyl ester enantiomers that provides some insight regarding the determinants responsible for lipase enantiodiscrimination. PMID:21391204

Piamtongkam, Rungtiwa; Duquesne, Sophie; Bordes, Florence; Barbe, Sophie; André, Isabelle; Marty, Alain; Chulalaksananukul, Warawut

2011-08-01

358

Salicylic acid, ethephon, and methyl jasmonate enhance ester regeneration in 1-MCP-treated apple fruit after long-term cold storage.  

PubMed

Volatile esters, primarily synthesized in peel tissues, are major aromatic components of apple fruits [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.]. The use of cold storage combined with 1-methylcyclopropene (1-MCP) treatment prolongs the life of apples but represses the regeneration of esters during poststorage ripening. In this study, the regeneration of total esters was significantly increased in apple fruits treated with salicylic acid (SA) and Ethephon (ETH) that had been treated once or twice with 1-MCP. However, methyl jasmonate (MeJA) treatment resulted in regeneration of total esters after a single 1-MCP treatment. To determine the mechanism by which SA, ETH, and MeJA regulate ester regeneration, the apple alcohol acyltransferase gene (MdAAT2) was investigated at the mRNA, protein, and enzyme activity levels. Genes associated with ethylene perception were also investigated by RT-PCR. The results suggest that MdAAT2 controls ester regeneration and that MdETR1 plays a key role in ethylene perception and regulation of downstream MdAAT2 gene expression during poststorage. Ester compounds and concentrations differed in peels treated with different signal molecules, indicating that regulation of the pathway upstream of straight-chain ester biosynthesis depended on the regulation of lipoxygenase (LOX) and alcohol dehydrogenase (ADH) activity by SA, ETH, and MeJA during poststorage ripening. PMID:16719511

Li, Da-Peng; Xu, Yun-Feng; Sun, Li-Ping; Liu, Li-Xia; Hu, Xiao-Li; Li, De-Quan; Shu, Huai-Rui

2006-05-31

359

An entourage effect: inactive endogenous fatty acid glycerol esters enhance 2-arachidonoyl-glycerol cannabinoid activity  

Microsoft Academic Search

2-Arachidonoyl-glycerol (2-Ara-Gl) has been isolated from various tissues and identified as an endogenous ligand for both cannabinoid receptors, CB1 and CB2. Here we report that in spleen, as in brain and gut, 2-Ara-Gl is accompanied by several 2-acyl-glycerol esters, two major ones being 2-linoleoyl-glycerol (2-Lino-Gl) and 2-palmitoyl-glycerol (2-Palm-Gl). These two esters do not bind to the cannabinoid receptors, nor do

Shimon Ben-Shabat; Ester Fride; Tzviel Sheskin; Tsippy Tamiri; Man-Hee Rhee; Zvi Vogel; Tiziana Bisogno; Luciano De Petrocellis; Vincenzo Di Marzo; Raphael Mechoulam

1998-01-01

360

Genome-Wide Transcriptome Analyses of Silicon Metabolism in Phaeodactylum tricornutum Reveal the Multilevel Regulation of Silicic Acid Transporters  

PubMed Central

Background Diatoms are largely responsible for production of biogenic silica in the global ocean. However, in surface seawater, Si(OH)4 can be a major limiting factor for diatom productivity. Analyzing at the global scale the genes networks involved in Si transport and metabolism is critical in order to elucidate Si biomineralization, and to understand diatoms contribution to biogeochemical cycles. Methodology/Principal Findings Using whole genome expression analyses we evaluated the transcriptional response to Si availability for the model species Phaeodactylum tricornutum. Among the differentially regulated genes we found genes involved in glutamine-nitrogen pathways, encoding putative extracellular matrix components, or involved in iron regulation. Some of these compounds may be good candidates for intracellular intermediates involved in silicic acid storage and/or intracellular transport, which are very important processes that remain mysterious in diatoms. Expression analyses and localization studies gave the first picture of the spatial distribution of a silicic acid transporter in a diatom model species, and support the existence of transcriptional and post-transcriptional regulations. Conclusions/Significance Our global analyses revealed that about one fourth of the differentially expressed genes are organized in clusters, underlying a possible evolution of P. tricornutum genome, and perhaps other pennate diatoms, toward a better optimization of its response to variable environmental stimuli. High fitness and adaptation of diatoms to various Si levels in marine environments might arise in part by global regulations from gene (expression level) to genomic (organization in clusters, dosage compensation by gene duplication), and by post-transcriptional regulation and spatial distribution of SIT proteins. PMID:19829693

Sapriel, Guillaume; Quinet, Michelle; Heijde, Marc; Jourdren, Laurent; Tanty, Veronique; Luo, Guangzuo; Le Crom, Stephane; Lopez, Pascal Jean

2009-01-01

361

Lithium-induced renal toxicity in rats: protection by a novel antioxidant caffeic acid phenethyl ester.  

PubMed

Lithium carbonate used in the long-term treatment of manic-depressive illness has been reported to lead to progressive renal impairment in rats and humans. Caffeic acid phenethyl ester (CAPE), a component of honeybee propolis, protects tissues from reactive oxygene species mediated oxidative stress in ischemia-reperfusion and toxic injuries. The beneficial effect CAPE on lithium-induced nephrotoxicity has not been reported yet. The purpose of this study was to examine a possible renoprotective effect of CAPE against lithium-induced nephrotoxicity in a rat model. Twenty-two adult male rats were randomly divided into three experimental groups, as follows: control group, lithium-treated group (Li), and lithium plus CAPE-treated group (Li+CAPE). Li were treated intraperitoneally (i.p.) with 25 mg/kg Li2CO3 solution in 0.9% NaCl twice daily for 4 weeks. CAPE was co-administered i.p. with a dose of 10 microM/kg/day for 4 weeks. Serum Li, blood urea nitrogen and plasma creatinine, urinary N-acetyl-beta-D-glucosaminidase (NAG, a marker of renal tubular injury), and malondialdehyde (MDA, an index of lipid peroxidation), were used as markers of oxidative stress-induced renal impairment in Li-treated rats. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were studied to evaluate the changes of antioxidant status in renal tissue. Serum Li levels were found high in the Li and Li+CAPE groups. In Li-administrated rats, urinary NAG and renal MDA levels were increased according to control and Li+CAPE groups (p < 0.05). CAPE caused a significant reduction in the levels of these parameters. Likewise, renal SOD, CAT and GSH-Px activities were decreased in Li-administrated animals; CAPE caused a significant increase in the activities of these antioxidant enzymes. In conclusion, CAPE treatment has a protective effect against Li-induced renal tubular damage and oxidative stress in a rat model. PMID:16132721

Oktem, Faruk; Ozguner, Fehmi; Sulak, Osman; Olgar, Seref; Akturk, Onur; Yilmaz, H Ramazan; Altuntas, Irfan

2005-09-01

362

A simple synthesis of 2-keto-3-deoxy-D-erythro-hexonic acid isopropyl ester, a key sugar for the bacterial population living under metallic stress.  

PubMed

2-Keto-3-deoxy-D-erythro-hexonic acid (KDG) is the key intermediate metabolite of the Entner Doudoroff (ED) pathway. A simple, efficient and stereoselective synthesis of KDG isopropyl ester is described in five steps from 2,3-O-isopropylidene-D-threitol with an overall yield of 47%. KDG isopropyl ester is studied as an attractive marker of a functional Entner Doudoroff pathway. KDG isopropyl ester is used to promote growth of ammonium producing bacterial strains, showing interesting features in the remediation of heavy-metal polluted soils. PMID:24333566

Grison, Claire M; Renard, Brice-Loïc; Grison, Claude

2014-02-01

363

ACUTE TOXICITY OF SELECTED SUBSTITUTED PHENOLS, BENZENES AND BENZOIC ACID ESTERS TO FATHEAD MINNOWS 'PIMEPHALES PROMELAS'  

EPA Science Inventory

Flow-through acute toxicity tests were conducted with 24 organic compounds using fathead minnows Pimephales promelas as test organisms. The tested toxicants consisted of 11 substituted phenols, four substituted benzenes and nine esters. The 96-h LC50 values determined for these c...

364

Characterization of Mefenamic Acid-Guaiacol Ester: Stability and Transport Across Caco-2 Cell Monolayers  

Microsoft Academic Search

Purpose. Prodrug of non-steroidal anti-inflammatory drugs (NSAIDs) or NSAIDs linked with guaiacol have been reported to suppress gastrointestinal (GI) toxicity or induce GI protective effect. In this study, mefenamic-guaiacol ester was synthesized and its physicochemical properties, stability, and transport across Caco-2 monolayers were investigated.

Vimon Tantishaiyakul; Kamonthip Wiwattanawongsa; Sirirat Pinsuwan; Srirat Kasiwong; Narubodee Phadoongsombut; Sanae Kaewnopparat; Nattha Kaewnopparat; Yon Rojanasakul

2002-01-01

365

?-Sulfonato palmitic acid methyl ester-hexaoxyethylene monododecyl ether mixed surfactant system: Interfacial, thermodynamic, and performance property study  

Microsoft Academic Search

Interfacial, thermodynamic, and performance properties of aqueous binary mixtures of ?-sulfonato palmitic acid methyl ester,\\u000a C14H29CH(SO3Na)COOCH3(PES), and hexaoxyethylene monododecyl ether, CH3(CH2)11(OCH2CH2)6OH (C12E6), were investigated with tensiometric, conductometric, fluorimetric, and viscometric techniques. The critical micelle concentration\\u000a (CMC), maximum surface excess, minimum area per molecule of surfactant at the air\\/water interface, and the thermodynamics\\u000a of micellization and adsorption were determined. The CMC

Sandeep R. Patil; Tsuneharu Mukaiyama; Animesh Kumar Rakshit

2004-01-01

366

Synthesis of [26,27- 2H 6]brassinosteroids from 23,24-bisnorcholenic acid methyl ester  

Microsoft Academic Search

A number of hexadeuterated brassinosteroids (BS) containing a hydroxy group at C-22 or a 22R,23R-diol function were prepared starting from 23,24-bisnorcholenic acid methyl ester for biosynthetic studies. Synthesis of the cyclic part was accomplished via the initial hydroboration–oxidation of ?5-double bond. The key step in the synthesis of the side chain involved addition of (2S)-[3,4-2H6]2,3-dimethylbutylphenyl sulfone to the corresponding C-22

Andrey P. Antonchick; Bernd Schneider; Vladimir N. Zhabinskii; Vladimir A. Khripach

2004-01-01

367

Synergistic Extraction and Separation of Heavy Lanthanide by Mixtures of Bis(2,4,4?trimethylpentyl)phosphinic Acid and 2?Ethylhexyl Phosphinic Acid Mono?2?Ethylhexyl Ester  

Microsoft Academic Search

The extraction of Yb from chloride solution has been studied using mixtures of bis(2,4,4?trimethylpentyl)phosphinic acid (Cyanex272) and 2?ethylhexyl phosphinic acid mono?2?ethylhexl ester (P507). The results show that Yb is extracted into heptane as YbA3(HA)3 with Cyanex272, YbL3(HL)3 with P507, and YbA2L4H3 with synergistic mixture. The equilibrium constants, formation constants, and thermodynamic functions have been determined. Extraction mechanism and extraction process

Ying Xiong; Xianglan Wang; Deqian Li

2005-01-01

368

The role of boric acid in the synthesis of Eni Carbon Silicates.  

PubMed

The influence of H3BO3 on the crystallization of hybrid organic-inorganic aluminosilicates denoted as Eni Carbon Silicates (ECS's) was investigated. Syntheses were carried out at 100 °C under different experimental conditions, using bridged silsesquioxanes of general formula (EtO)3Si-R-Si(OEt)3 (R = -C6H4- (BTEB), -C10H6- (BTEN) and -C6H4-C6H4- (BTEBP)), in the presence of equimolar concentrations of NaAlO2 and H3BO3. The study, involving the synthesis of three different but structurally related phases (ECS-14 from BTEB, ECS-13 here described for the first time from BTEN, and ECS-5 from BTEBP), confirmed a catalytic role for H3BO3 which in general increased the crystallization rate and improved the product quality in terms of amount of crystallized phase (crystallinity), size of the crystallites and phase purity, while it was weakly incorporated in trace amounts in the framework of ECS's. PMID:24835643

Zanardi, Stefano; Bellussi, Giuseppe; Parker, Wallace O'Neil; Montanari, Erica; Bellettato, Michela; Cruciani, Giuseppe; Carati, Angela; Guidetti, Stefania; Rizzo, Caterina; Millini, Roberto

2014-07-21

369

Antinociceptive activity of Paederosidic Acid Methyl Ester (PAME) from the n-butanol fraction of Paederia scandens in mice.  

PubMed

Antinociceptive activity of Paederosidic Acid Methyl Ester (PAME), a chemical compound isolated from the n-butanol fraction of Paederia scandens, was evaluated in mice using chemical and thermal models of nociception. PAME given by intraperitoneal injection at doses of 20, 40 and 60 mg/kg produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid, subplantar formalin or capsaicin injections and on thermal nociception in the tail-flick test and the hot plate test. In the pentobarbital sodium-induced sleep time test and the open-field test, PAME neither significantly enhanced the pentobarbital sodium-induced sleep time nor impaired the motor performance, indicating that the observed antinociceptive activity of PAME was unlikely due to sedation or motor abnormality. Core body temperature measurement showed that PAME did not affect temperature within a 2-h period. Moreover, PAME-induced antinociception in the hot plate test was insensitive to naloxone or nimodipine but significantly antagonized by L-NAME (N (G)-nitro-L-arginine methyl ester), methylene blue and glibenclamide. These results suggested that PAME-produced antinociception was possibly related to the pathway of NO-cGMP-ATP sensitive K(+) channels, which merited further studies regarding the precise site and mechanisms of action. PMID:19409921

Chen, Yu-Feng; Huang, Ying; Tang, Wei-Zhong; Qin, Lu-Ping; Zheng, Han-chen

2009-08-01

370

Importance of Solvation in Understanding the Chiroptical Spectra of Natural Products in Solution Phase: Garcinia Acid Dimethyl Ester  

PubMed Central

The optical rotatory dispersion (ORD), electronic circular dichroism (ECD), and vibrational circular dichroism (VCD) spectra of (+)-garcinia acid dimethyl ester have been measured and analyzed by comparison with the corresponding spectra predicted by quantum chemical methods for (2S,3S)-garcinia acid dimethyl ester. For solution-phase calculations the recently developed continuous surface charge polarizable continuum model (PCM) has been used. It is found that gas-phase predictions and PCM predictions at the B3LYP/aug-cc-pVDZ level yield nearly mirror-image ECD spectra in the 190–250 nm region for the same absolute configuration and that gas-phase ECD predictions lead to incorrect absolute configuration. At the CAM-B3LYP/aug-cc-pVDZ level, however, gas-phase predictions and PCM predictions of ECD in the 190–250 nm region are not so different, but PCM predictions provide better agreement with the experimental observations. For carbonyl stretching vibrations, the vibrational band positions predicted at the B3LYP/aug-cc-pVDZ level in gas-phase calculations differ significantly from the corresponding experimentally observed band positions, and this discrepancy has also been corrected by the use of PCM. In addition, the solution-phase VCD predictions provided better agreement (with experimental VCD observations) than gas-phase VCD predictions. These observations underscore the importance of including solvent effects in quantum chemical calculations of chiroptical spectroscopic properties. PMID:21114277

Polavarapu, Prasad L.; Scalmani, Giovanni; Hawkins, Edward K.; Rizzo, Carmelo; Jeirath, Neha; Ibnusaud, Ibrahim; Habel, Deenamma; Nair, Divya Sadasivan; Haleema, Simimole

2013-01-01

371

Extended use of a selective inhibitor of acid lipase for the diagnosis of Wolman disease and cholesteryl ester storage disease.  

PubMed

Lysosomal acid lipase (LAL) deficiency produces two well defined inborn disorders, Wolman disease (WD) and cholesteryl ester storage disease (CESD). WD is a severe, early-onset condition involving massive storage of triglycerides and cholesteryl esters in the liver, with death usually occurring before one year of life. CESD is a more attenuated, later-onset disease that leads to a progressive and variable liver dysfunction. Diagnosis of LAL deficiency is mainly based on the enzyme assay of LAL activity in fibroblasts. Recently, a selective acid lipase inhibitor was used for the determination of enzyme activity in dried-blood filter paper (DBFP) samples. To extend and to validate these studies, we tested LAL activity with selective inhibition on DBFP samples, leukocytes and fibroblasts. Our results showed a clear discrimination between patients with LAL deficiency and healthy controls when using DBFP, leukocytes or fibroblasts (p<0.001). Deficiency of LAL was also demonstrated in individuals referred to our laboratory with suspected clinical diagnosis of WD, CESD, and Niemann-Pick type B. We conclude that the assay of LAL using selective inhibitor is a reliable and useful method for the identification of LAL deficiency, not only in DBFP samples but also in leukocytes and fibroblasts. This is important as enzyme replacement therapy for LAL deficiency is currently being developed, making the correct diagnosis a critical issue. PMID:24508470

Civallero, G; De Mari, J; Bittar, C; Burin, M; Giugliani, R

2014-04-10

372

[Distribution of phthalate acid esters in waters and Potamogeton crispus L. from the mainstream of Haihe River].  

PubMed

Concentrations of phthalate acid esters(PAEs) in waters and aquatic plant, Potamogeton crispus L., were measured from March 29 to May 25, 2008 in the mainstream of Haihe River. The results showed that dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) were detected in all samples of waters and Potamogeton crispus L.. Concentrations of DBP and DEHP in water samples ranged from 0.35-40.68 microg/L (mean 7.32 microg/L) and 3.54-101.2 microg/L (mean 21.72 microg/L), respectively. Concentrations of DBP and DEHP in Potamogeton crispus L. ranged from 0.007-0.242 microg/g (0.078 microg/g) and 0.163-1.286 microg/g (0.457 microg/g), respectively. Concentrations of DBP and DEHP in Potamogeton crispus L. reached the highest value during Potamogeton crispus L. blooming period and were significantly related to concentrations of DBP and DEHP in waters. PCF values of DBP and DEHP by Potamogeton crispus L. were obviously above 1, and the PCFs value reached the maxima during the early growing period and the minima during the period of decay. Concentration and PCF of DBP were both lower than those of DEHP. Potamogeton crispus L. was an important sink of phthalate acid esters, a kind of hydrophobic organic compounds, because of its abundance in Haihe River. PMID:20063741

Chi, Jie; Zheng, Yan

2009-11-01

373

Simultaneous determination of total fatty acid esters of chloropropanols in edible oils by gas chromatography-mass spectrometry with solid-supported liquid-liquid extraction.  

PubMed

This study aimed to establish a novel robust method for the simultaneous determination of total fatty acid esters of 4 chloropropanols including fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD esters), 2-monochloropropane-1,3-diol (2-MCPD esters), 1,3-dichloropropan-2-ol (1,3-DCP esters) and 2,3-dichloropropan-1-ol (2,3-DCP esters) in edible oils. In this method, sodium methylate in methanol was used as the reagent for the ester cleavage reaction of chloropropanols esters. The reaction products were extracted by a sodium sulfate solution, and then purified by solid-supported liquid-liquid extraction (SLE) using diatomaceous earth (Hydromatrix™) as the sorbent. Finally, the extracts were derivatized with heptafluorobutyrylim idazole (HFBI) and analyzed by gas chromatography-mass spectrometry (GC-MS). Quantification was achieved using deuterated chloropropanols as their respective internal standards, including 3-MCPD-d5, 2-MCPD-d5, 1,3-DCP-d5 and 2,3-DCP-d5. A good linear relationship between peak area and concentrations was obtained within the range of 0.025-2.000mgL(-1) with a correlation coefficients not less than 0.999 for all the chloropropanols esters. The limits of detection (LODs) of esters of 3-MCPD, 2-MCPD, 1,3-DCP and 2,3-DCP (calculated as corresponding chloropropanols) were 30, 30, 100 and 30?gkg(-1), respectively. The average recoveries of the 3-MCPD esters and the 4 chloropropanols spiked at 0.1, 0.5 and 2mgkg(-1) into blank oil matrix were typically in a range from 70.7% to 113.3%. The robust method validation data including calibration, LOD/LOQ, accuracy and repeatability and proficiency test results (Z-score: -0.5) of the official Food Analysis Performance Assessment Scheme (FAPAS) indicated that the present quantitative method could be successfully applied to the determination of total chloropropanols esters in various edible oils. PMID:24070627

Liu, Qing; Han, Feng; Xie, Ke; Miao, Hong; Wu, Yongning

2013-11-01

374

Human lysosomal acid lipase/cholesteryl ester hydrolase and human gastric lipase: identification of the catalytically active serine, aspartic acid, and histidine residues.  

PubMed

Human lysosomal acid lipase/cholesteryl ester hydrolase (HLAL), human gastric lipase (HGL), and rat lingual lipase (RLL) constitute a family of mammalian lipases characterized by an acidic pH optimum. HGL and RLL are secreted by the chief cells of the stomach and by the serous von Ebner's glands of the tongue, respectively, and hydrolyze dietary longchain triglycerides in the gastrointestinal tract. HLAL, in contrast, catalyzes the intralysosomal degradation of both triglycerides and cholesteryl esters in virtually all cells except erythrocytes. All three enzymes are proposed to be serine esterases with a catalytic Ser-Asp-His triad similar to other lipases, despite their sensitivity towards sulfhydryl modifying reagents. To investigate the role of conserved serine, aspartic acid, and histidine residues in HLAL and HGL, we constructed 24 mutant lipases with single amino acid substitutions using the site-directed mutagenesis approach. Our combined data strongly support the conclusion that Ser153, Asp324, and His355 are components of the catalytic triad of HLAL and HGL. Structural integrity of the conserved His-Gly dipeptide of lipases also appears to be important for neutral lipid hydrolysis, as replacement of His65 by glutamine abolished HLAL and HGL enzymic activity. Substitution of HLAL residues Asp93, Asp130, and Asp328 with glycine, in contrast, had a more pronounced impact on cholesteryl oleate hydrolysis than on triglyceride hydrolysis. These results provide new insights into the structural basis of HLAL and HGL function. PMID:9186907

Lohse, P; Chahrokh-Zadeh, S; Lohse, P; Seidel, D

1997-05-01

375

Ordered cleavage of myeloperoxidase ester bonds releases active site heme leading to inactivation of myeloperoxidase by benzoic acid hydrazide analogs.  

PubMed

Myeloperoxidase (MPO) catalyzes the breakdown of hydrogen peroxide and the formation of the potent oxidant hypochlorous acid. We present the application of the fluorogenic peroxidase substrate 10-acetyl-3,7-dihydroxyphenoxazine (ADHP) in steady-state and transient kinetic studies of MPO function. Using initial kinetic parameters for the MPO system, we characterized under the same conditions a number of gold standards for MPO inhibition, namely 4-amino benzoic acid hydrazide (4-ABAH), isoniazid and NaN3 before expanding our focus to isomers of 4-ABAH and benzoic acid hydrazide analogs. We determined that in the presence of hydrogen peroxide that 4-ABAH and its isomer 2-ABAH are both slow-tight binding inhibitors of MPO requiring at least two steps, whereas NaN3 and isoniazid-based inhibition has a single observable step. We also determined that MPO inhibition by benzoic acid hydrazide and 4-(trifluoromethyl) benzoic acid hydrazide was due to hydrolysis of the ester bond between MPO heavy chain Glu 242 residue and the heme pyrrole A ring, freeing the light chain and heme b fragment from the larger remaining MPO heavy chain. This new mechanism would essentially indicate that the benzoic acid hydrazide analogs impart inhibition through initial ejection of the heme catalytic moiety without prior loss of the active site iron. PMID:24632143

Huang, Jiansheng; Smith, Forrest; Panizzi, Peter

2014-04-15

376

Inhibitory Activities of Propolis and Its Promising Component, Caffeic Acid Phenethyl Ester, against Amyloidogenesis of Human Transthyretin.  

PubMed

Transthyretin (TTR) is a homotetrameric serum protein associated with amyloidoses such as familial amyloid polyneuropathy and senile systemic amyloidosis. The amyloid fibril formation of TTR can be inhibited through stabilization of the TTR tetramer by the binding of small molecules. In this study, we examined the inhibitory potency of caffeic acid phenethyl ester (CAPE) and its derivatives. Thioflavin T assay showed that CAPE suppressed the amyloid fibril formation of TTR. Comparative analysis of the inhibitory potencies revealed that phenethyl ferulate was the most potent among the CAPE derivatives. The binding of phenethyl ferulate and the selected compounds to TTR were confirmed by the 8-anilino-1-naphthalenesulfonic acid displacement and X-ray crystallography. It was also demonstrated that Bio 30, which is a CAPE-rich commercially available New Zealand propolis, inhibited TTR amyloidogenesis and stabilized the TTR tetramer. These results suggested that a propolis may be efficient for preventing TTR amyloidosis. PMID:25314129

Yokoyama, Takeshi; Kosaka, Yuto; Mizuguchi, Mineyuki

2014-11-13

377

Guiding optimal biofuels : a comparative analysis of the biochemical production of ethanol and fatty acid ethyl esters from switchgrass.  

SciTech Connect

In the current study, processes to produce either ethanol or a representative fatty acid ethyl ester (FAEE) via the fermentation of sugars liberated from lignocellulosic materials pretreated in acid or alkaline environments are analyzed in terms of economic and environmental metrics. Simplified process models are introduced and employed to estimate process performance, and Monte Carlo analyses were carried out to identify key sources of uncertainty and variability. We find that the near-term performance of processes to produce FAEE is significantly worse than that of ethanol production processes for all metrics considered, primarily due to poor fermentation yields and higher electricity demands for aerobic fermentation. In the longer term, the reduced cost and energy requirements of FAEE separation processes will be at least partially offset by inherent limitations in the relevant metabolic pathways that constrain the maximum yield potential of FAEE from biomass-derived sugars.

Paap, Scott M.; West, Todd H.; Manley, Dawn Kataoka; Dibble, Dean C.; Simmons, Blake Alexander; Steen, Eric J. [Joint BioEnergy Institute, Emeryville, CA; Beller, Harry R. [Lawrence Berkeley National Laboratory, Berkeley, CA; Keasling, Jay D. [Lawrence Berkeley National Laboratory, Berkeley, CA; Chang, Shiyan [Tsinghua University, Beijing, PR China

2013-01-01

378

Palladium-catalyzed C-N and C-O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols  

PubMed Central

Summary Simple and efficient procedures for palladium-catalyzed cross-coupling reactions of N-substituted 4-bromo-7-azaindole (1H-pyrrole[2,3-b]pyridine), with amides, amines, amino acid esters and phenols through C–N and C–O bond formation have been developed. The C–N cross-coupling reaction of amides, amines and amino acid esters takes place rapidly by using the combination of Xantphos, Cs2CO3, dioxane and palladium catalyst precursors Pd(OAc)2/Pd2(dba)3. The combination of Pd(OAc)2, Xantphos, K2CO3 and dioxane was found to be crucial for the C–O cross-coupling reaction. This is the first report on coupling of amides, amino acid esters and phenols with N-protected 4-bromo-7-azaindole derivatives. PMID:23209536

Surasani, Rajendra; Rao, A V Dhanunjaya; Chandrasekhar, K B

2012-01-01

379

Palladium-catalyzed C-N and C-O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols.  

PubMed

Simple and efficient procedures for palladium-catalyzed cross-coupling reactions of N-substituted 4-bromo-7-azaindole (1H-pyrrole[2,3-b]pyridine), with amides, amines, amino acid esters and phenols through C-N and C-O bond formation have been developed. The C-N cross-coupling reaction of amides, amines and amino acid esters takes place rapidly by using the combination of Xantphos, Cs(2)CO(3), dioxane and palladium catalyst precursors Pd(OAc)(2)/Pd(2)(dba)(3). The combination of Pd(OAc)(2), Xantphos, K(2)CO(3) and dioxane was found to be crucial for the C-O cross-coupling reaction. This is the first report on coupling of amides, amino acid esters and phenols with N-protected 4-bromo-7-azaindole derivatives. PMID:23209536

Surasani, Rajendra; Kalita, Dipak; Rao, A V Dhanunjaya; Chandrasekhar, K B

2012-01-01

380

The anticonvulsant sulfamates. 2. (1,4-benzodioxin-2(3H)-yl)- and (1,2,3,4-tetrahydro-2-naphthalenyl) methyl sulfamic acid esters  

Microsoft Academic Search

The crystal structures of two sulfamates: (1,4-benzodioxin-2(3H)-yl) methyl sulfamic acid ester, C9H11NO5S (1); and (1,2,3,4-tetrahydro-2-naphthalenyl) methyl sulfamic acid ester, C11H15NO3S (2), have been determined by single crystal X-ray diffraction. In compound 1, the conformation of dihydrodioxine ring is close to an ideal half-chair conformation. In 2 the puckered tetrahydrophenyl ring is observed in two conformations: a half-chair, and a sofa

M. Kubicki; P. W. Codding

2001-01-01

381

Astaxanthin from the red crab langostilla (Pleuroncodes planipes): optical R/S isomers and fatty acid moieties of astaxanthin esters.  

PubMed

The composition of the fatty acids of astaxanthin esters and the distribution of astaxanthin optical RS isomers in the esterified and unesterified astaxanthin fractions extracted from the meal of the pelagic red crab langostilla (Pleuroncodes planipes; Decapoda, Anomura) were determined. Astaxanthin diesters comprised approximately 70%, monoesterified astaxanthin approximately 12%, and unesterified astaxanthin approximately 10% of total carotenoids, respectively. Unidentified carotenes and minor yellow xanthophylls represented approximately 8% of the total carotenoids. Three astaxanthin diester fractions (ratio 5:4:1) and one monoester fraction were clearly distinguished by thin-layer chromatography, and fatty acid moieties were determined in all of them. Saturated fatty acids accumulated in astaxanthin diesters, but were reduced in the monoester fraction when compared to langostilla crude oil extract (CE). Astaxanthin diesters, but not monoesters were enriched in C16:0 and C18:1n-9, when compared to the CE. Astaxanthin monoesters were rich in polyunsaturated fatty acids (approximately 70% of total fatty acids), in particular C20:5n-3 and C22:6n-3. Acylation of astaxanthin in langostilla seems to be selective rather than specific. The three diesterified astaxanthin fractions of langostilla had a ratio of approximately 3:1:3 between the (3R,3'R)-, (3R,3'S)-, and (3S,3'S)-astaxanthin isomers, whereas in the monoesterified and unesterified fractions the ratio was approximately 4:1:4. The astaxanthin optical RS isomer composition indicates that langostilla is unable to racemize astaxanthin. PMID:12431411

Coral-Hinostroza, Gladis Nancy; Bjerkeng, Bjørn

2002-11-01

382

Hydroxycinnamoyltransferases lnvolved in the Accumulation of Caffeic Acid Esters in Cametophytes and Sporophytes of Equisetum arvense  

Microsoft Academic Search

Four hydroxycinnamoyltransferases from Equisefum arvense L. were studied that catalyze the formation of mono-Ocaffeoyl- meso-tartrate, di-O-caffeoyl-meso-tartrate, 5-Ocaffeoylshikimate (dactylifrate), and 5-Ocaffeoylquinate (chlorogenate). lhe en- zymes were classified as coenzyme A (COA)-ester-dependent acyl- transferases (EC 2.3.1), i.e. hydroxycinnamoyl-CoAmeso-tartrate hydroxycinnamoyltransferase (CTT), hydroxycinnamoyl-CoA:caf- feoyl-meso-tartrate hydroxycinnamoyltransferase (CCT), hydroxy- cinnamoyl-CoAshikimate hydroxycinnamoyltransferase (CST), and hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase. The CTT, CCT, and CST were partially purified and separated from

Marianne Hohlfeld; Markus Veit; Dieter Strack

383

Production and characterization of methyl ester sophorolipids with 22-carbon-fatty acids  

Microsoft Academic Search

In this study, various fatty acids of 18 and 22 carbons were used as substrates to produce sophorolipids in Candida bombicola ATCC 22214. Methyl esterification of erucic acid and C22-enriched rapeseed oil generated mainly acidic sophorolipids with different degrees of saturation in the fatty acid chain, which was demonstrated by structural analysis using HPLC, LC–MS and NMR spectroscopy. Regardless of

Jae Dong Shin; Jeongmi Lee; Yong Bum Kim; In-sun Han; Eun-Ki Kim

2010-01-01

384

Extraction of rare earth metals with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester in the presence of diethylenetriaminepentaacetic acid in aqueous phase  

SciTech Connect

The extraction equilibria of rare earth metals with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (commercial name, PC-88A, henceforth abbreviated as HR) dissolved in n-heptane were measured at 303 K. It was found that rare earth metals are extracted with the dimer of the extractant, (HR){sub 2}, as follows. M{sub aq}{sup 3+} + 3(HR){sub 2 org} MR{sub 3} {center_dot} 3HR{sub org} + 3H{sub aq}{sup +} The extraction equilibrium constants of metals were obtained and compared with the extraction equilibrium constants obtained by di(2-ethylhexyl)phosphoric acid (henceforth DZEHPA). Furthermore, the extraction equilibria of rare earth metals with PC-88A in the presence of diethylenetriaminepentaacetic acid (henceforth DTPA) in an aqueous phase were also measured to discuss the effect of DTPA on the extraction of rare earth metals. 13 refs., 8 figs., 2 tabs.

Kubota, Fukiko; Goto, Masahiro; Nakashio, Fumiyuki [Kyushu Univ., Fukuoka (Japan)

1993-07-01

385

Selective uptake of cholesteryl esters from apolipoprotein-E-free high-density lipoproteins by rat parenchymal cells in vivo is efficiently coupled to bile acid synthesis.  

PubMed Central

[3H]Cholesteryl ester-labelled human high-density lipoprotein (HDL) was injected into rats and its decay, intrahepatic cellular distribution and the kinetics of biliary secretion were determined. At 10 min after injection the hepatic uptake of cholesteryl esters from HDL was 3-fold higher as compared with the apolipoprotein. Selective uptake was exerted only by parenchymal cells (5.6-fold more cholesteryl esters than apolipoprotein) and not by liver endothelial or Kupffer cells. The kinetics of biliary secretion of processed cholesteryl esters initially associated with HDL or low-density lipoprotein (LDL) were compared in unrestrained rats, equipped with permanent catheters in bile duct, duodenum and heart. At 72 h after injection of [3H]cholesteryl oleate-labelled HDL, 51.0 +/- 2.5% of the injected dose was recovered as bile acids, which is about twice as high as the secretion of biliary radioactivity after injection of [3H]cholesteryl oleate-labelled LDL. Oestradiol treatment stimulated only liver uptake of LDL cholesteryl esters, and resulted in a 2-fold higher liver uptake than with HDL. However, the rate of radioactive bile acid formation from [3H]cholesteryl oleate-labelled HDL was still more rapid than for LDL. It is concluded that the selective uptake pathway for cholesteryl esters from HDL in parenchymal cells is more efficiently coupled to the formation of bile acids than is the cholesteryl ester uptake from LDL. This efficient coupling may facilitate the role of HDL in reverse cholesterol transport. PMID:1747108

Pieters, M N; Schouten, D; Bakkeren, H F; Esbach, B; Brouwer, A; Knook, D L; van Berkel, T J

1991-01-01

386

Changes in ester-linked phospholipid fatty acid profiles of subsurface bacteria during starvation and desiccation in a porous medium  

SciTech Connect

Ester-linked phospholipid fatty acid (PLFA) profiles of a Pseudomonas aureofaciens strain and an Arthrobacter protophormiae strain, each isolated from a subsurface sediment, were quantified in a starvation experiment in a silica sand porous medium under moist and dry conditions. Washed cells were added to sand microcosms and maintained under saturated conditions or subjected to desiccation by slow drying over a period of 16 days. In a third treatment, cells were added to saturated microcosms along with organic nutrients and maintained under saturated conditions. The numbers of culturable cells of both bacterial strains declined to below detection level within 16 days in both the moist and dried nutrient-deprived conditions, while direct counts and total PLFAs remained relatively constant. Both strains of bacteria maintained culturability in the nutrient-amended microcosms. The dried P. aureofaciens cells showed increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl fatty acids to their monoenoic precursors. P. aureofaciens starved under moist conditions showed few changes in PLFA profiles during the 16-day incubation, whereas cells incubated in the presence of nutrients showed decreases in the ratios of both saturated fatty acids to unsaturated fatty acids and cyclopropyl fatty acids to their monoenoic precursors. The PLFA profiles of A. protophormiae changed very little in response to either nutrient deprivation or desiccation. Diglyceride fatty acids, proposedindicators of dead or lysed cells, remained relatively constant throughout the experiment. The results of this laboratory experiment can be useful for interpreting PLFA profiles of subsurface communities of microorganisms for the purpose of determining their physiological status. 43 refs., 8 figs.

Kieft, T.L. [New Mexico Institute of Mining and Technology, Socorro, NM (United States); Ringelberg, D.B.; White, D.C. [Univ. of Tennessee, Knoxville, TN (United States)

1994-09-01

387

Bias voltage dependence of molecular orientation of dialkyl ketone and fatty acid alkyl ester at the liquid-graphite interface  

NASA Astrophysics Data System (ADS)

Molecular orientations of self-assembled 18-pentatriacontanone (as ketone) and stearyl stearate (as ester) monolayers adsorbed on a graphite surface were studied by scanning tunneling microscopy (STM) at the liquid-solid interface. At a positive sample bias, the central areas of the dialkyl ketone and fatty acid alkyl ester molecules in the STM images appeared as two bright regions on both sides of a dim spot and a bright region on one side of a dim spot, whereas at a negative sample bias, the areas appeared dim. This contrast variation indicates that a perpendicular carbon skeleton-plane orientation with the CO pointing down on the surface is favorable for a substrate with positive charge and vice versa because of the greater electronegativity of the oxygen atom. Upon the bias voltage reversal, the delay time for the STM image contrast change in the region was observed on a time scale of minutes. The difference between the delay time lengths for the direction of bias polarity change indicates that the perpendicular configuration with CO pointing up is more stable than that with CO pointing down. These results indicate that the use of an electric field along a direction vertical to the monolayer on the substrate provides control over the orientations of the molecules between two stable states at the liquid-solid interface.

Hibino, Masahiro; Tsuchiya, Hiroshi

2014-10-01

388

Biocatalytic potential of lipase from Staphylococcus sp. MS1 for transesterification of jatropha oil into fatty acid methyl esters.  

PubMed

An extracellular lipase producing isolate Staphylococcus sp. MS1 was optimized for lipase production and its biocatalytic potential was assessed. Medium with tributyrin (0.25 %) and without any exogenous inorganic nitrogen source was found to be optimum for lipase production from Staphylococcus sp. MS1. The optimum pH and temperature for lipase production were found to be pH 7 and 37 °C respectively, showing lipase activity of 37.91 U. It showed good lipase production at pH 6-8. The lipase was found to be stable in organic solvents like hexane and petroleum ether, showing 98 and 88 % residual activity respectively. The biotransformation using the concentrated enzyme in petroleum ether resulted in the synthesis of fatty acid methyl esters like methyl oleate, methyl palmitate and methyl stearate. Thus, the lipase under study has got the potential to bring about transesterification of oils into methyl esters which can be exploited for various biotechnological applications. PMID:25115850

Sharma, Monika; Singh, Shelley Sardul; Maan, Pratibha; Sharma, Rohit

2014-11-01

389

Wolman disease/cholesteryl ester storage disease: efficacy of plant-produced human lysosomal acid lipase in mice.  

PubMed

Lysosomal acid lipase (LAL) is an essential enzyme that hydrolyzes triglycerides (TGs) and cholesteryl esters (CEs) in lysosomes. Genetic LAL mutations lead to Wolman disease (WD) and cholesteryl ester storage disease (CESD). An LAL-null (lal(-/-)) mouse model resembles human WD/CESD with storage of CEs and TGs in multiple organs. Human LAL (hLAL) was expressed in Nicotiana benthamiana using the GENEWARE expression system (G-hLAL). Purified G-hLAL showed mannose receptor-dependent uptake into macrophage cell lines (J774E). Intraperitoneal injection of G-hLAL produced peak activities in plasma at 60 min and in the liver and spleen at 240 min. The t(1/2) values were: approximately 90 min (plasma), approximately 14 h (liver), and approximately 32 h (spleen), with return to baseline by approximately 150 h in liver and approximately 200 h in spleen. Ten injections of G-hLAL (every 3 days) into lal(-/-) mice produced normalization of hepatic color, decreases in hepatic cholesterol and TG contents, and diminished foamy macrophages in liver, spleen, and intestinal villi. All injected lal(-/-) mice developed anti-hLAL protein antibodies, but suffered no adverse events. These studies demonstrate the feasibility of using plant-expressed, recombinant hLAL for the enzyme therapy of human WD/CESD with general implications for other lysosomal storage diseases. PMID:18413899

Du, Hong; Cameron, Terri L; Garger, Stephen J; Pogue, Gregory P; Hamm, Lee A; White, Earl; Hanley, Kathleen M; Grabowski, Gregory A

2008-08-01

390

Wolman disease/cholesteryl ester storage disease: efficacy of plant-produced human lysosomal acid lipase in mice*  

PubMed Central

Lysosomal acid lipase (LAL) is an essential enzyme that hydrolyzes triglycerides (TGs) and cholesteryl esters (CEs) in lysosomes. Genetic LAL mutations lead to Wolman disease (WD) and cholesteryl ester storage disease (CESD). An LAL-null (lal?/?) mouse model resembles human WD/CESD with storage of CEs and TGs in multiple organs. Human LAL (hLAL) was expressed in Nicotiana benthamiana using the GENEWARE® expression system (G-hLAL). Purified G-hLAL showed mannose receptor-dependent uptake into macrophage cell lines (J774E). Intraperitoneal injection of G-hLAL produced peak activities in plasma at 60 min and in the liver and spleen at 240 min. The t1/2 values were: ?90 min (plasma), ?14 h (liver), and ?32 h (spleen), with return to baseline by ?150 h in liver and ?200 h in spleen. Ten injections of G-hLAL (every 3 days) into lal?/? mice produced normalization of hepatic color, decreases in hepatic cholesterol and TG contents, and diminished foamy macrophages in liver, spleen, and intestinal villi. All injected lal?/? mice developed anti-hLAL protein antibodies, but suffered no adverse events. These studies demonstrate the feasibility of using plant-expressed, recombinant hLAL for the enzyme therapy of human WD/CESD with general implications for other lysosomal storage diseases. PMID:18413899

Du, Hong; Cameron, Terri L.; Garger, Stephen J.; Pogue, Gregory P.; Hamm, Lee A.; White, Earl; Hanley, Kathleen M.; Grabowski, Gregory A.

2008-01-01

391

Biosynthesis of D-alanyl-lipoteichoic acid by Lactobacillus casei: interchain transacylation of D-alanyl ester residues  

SciTech Connect

Lipoteichoic acid (LTA) from Lactobacillus casei contains poly(glycerophosphate) substituted with D-alanyl ester residues. The distribution of these residues in the in vitro-synthesized polymer is uniform. Esterification of LTA with D-alanine may occur in one of two modes: (i) addition at random or (ii) addition at a defined locus in the poly(glycerophosphate) chain followed by redistribution of the ester residues. A time-dependent transacylation of these residues from D-(/sup 14/C)alanyl-lipophilic LTA to hydrophilic acceptor was observed. The hydrophilic acceptor was characterized as D-alanyl-hydrophilic LTA. This transacylation requires neither ATP nor the D-alanine incorporation system, i.e., the D-alanine activating enzyme and D-alanine:membrane acceptor ligase. No evidence for an enzyme-catalyzed transacylation reaction was observed. The authors propose that this process of transacylation may be responsible for the redistribution of D-alanyl residues after esterification to the poly(glycerophosphate). As a result, it is difficult to distinguish between these proposed modes of addition.

Childs, W.C. 3d.; Taron, D.J.; Neuhaus, F.C.

1985-06-01

392

Lipase immobilization on hyper-cross-linked polymer-coated silica for biocatalytic synthesis of phytosterol esters with controllable fatty acid composition.  

PubMed

In this study, a novel mixed-mode composite material, SiO(2)@P(MAA-co-VBC-co-DVB), was prepared via the hyper-cross-linking of its precursor, which was produced via suspension polymerization in the presence of SiO(2) particles. Candida rugosa lipase (CRL) was immobilized on the SiO(2)@P(MAA-co-VBC-co-DVB) particles via hydrophobic and weak cation-exchange interaction. The resulting immobilized CRL showed much better thermal stability and reusability in comparison to free CRL. On the basis of the excellent biocatalyst prepared, a method for high-efficiency enzymatic esterification of phytosterols with different fatty acids to produce the corresponding phytosterol esters was developed. Six phytosterol esters with conversions above 92.1% and controllable fatty acid composition were obtained under the optimized conditions: 80 ?mol/mL phytosterols, 160 ?mol/mL linolenic acid, and 15 mg/mL CRL@HPCS at 300 rpm and 50 °C for 7 h in 30 mL of isooctane. The prepared phytosterol esters possessed a low acid value (?0.86 mg of KOH/g), peroxide value (?3.3 mequiv/kg), and conjugated diene value (?1.74 mmol/kg) and high purity (?97.8%) and fatty solubility (?28.9 g/100 mL). All the characteristics favored the wide application of phytosterol esters with controllable fatty acid composition in different fields of functional food. PMID:23199227

Zheng, Ming-Ming; Lu, Yong; Huang, Feng-Hong; Wang, Lian; Guo, Ping-Mei; Feng, Yu-Qi; Deng, Qian-Chun

2013-01-01

393

Substituted thiobenzoic acid S-benzyl esters as potential inhibitors of a snake venom phospholipase A2: Synthesis, spectroscopic and computational studies  

NASA Astrophysics Data System (ADS)

4-Chlorothiobenzoic acid S-benzyl ester (I), 3-nitrothiobenzoic acid S-benzyl ester (II), 4-nitrothiobenzoic acid S-benzyl ester (III) and 4-methylthiobenzoic acid S-benzyl ester (IV) were prepared and characterized by 1H and 13C NMR, Mass spectrometry and IR spectroscopy. Quantum chemical calculations were performed with Gaussian 09 to calculate the geometric parameters and vibrational spectra. Phospholipase A2 (PLA2) was purified from Crotalus durissus cumanensis venom by molecular exclusion chromatography, followed by reverse phase-high performance liquid chromatography. Two studies of the inhibition of phospholipase A2 activity were performed using phosphatidilcholine and 4-nitro-3-octanoyloxybenzoic acid as substrates, in both cases compound II showed the best inhibitory ability, with 74.89% and 69.91% of inhibition, respectively. Average percentage of inhibition was 52.49%. Molecular docking was carried out with Autodock Vina using as ligands the minimized structures of compounds (I-IV) and as protein PLA2 (PDB code 2QOG). The results suggest that compounds I-IV could interact with His48 at the active site of PLA2. In addition, all compounds showed Van der Waals interactions with residues from hydrophobic channel of the enzyme. This interaction would impede normal catalysis cycle of the PLA2.

Henao Castañeda, I. C.; Pereañez, J. A.; Jios, J. L.

2012-11-01

394

Fast and accurate preparation fatty acid methyl esters by microwave-assisted derivatization in the yeast Saccharomyces cerevisiae.  

PubMed

We present a fast and accurate method for preparation of fatty acid methyl esters (FAMEs) using microwave-assisted derivatization of fatty acids present in yeast samples. The esterification of free/bound fatty acids to FAMEs was completed within 5 min, which is 24 times faster than with conventional heating methods. The developed method was validated in two ways: (1) through comparison with a conventional method (hot plate) and (2) through validation with the standard reference material (SRM) 3275-2 omega-3 and omega-6 fatty acids in fish oil (from the Nation Institute of Standards and Technology, USA). There were no significant differences (P>0.05) in yields of FAMEs with both validations. By performing a simple modification of closed-vessel microwave heating, it was possible to carry out the esterification in Pyrex glass tubes kept inside the closed vessel. Hereby, we are able to increase the number of sample preparations to several hundred samples per day as the time for preparation of reused vessels was eliminated. Pretreated cell disruption steps are not required, since the direct FAME preparation provides equally quantitative results. The new microwave-assisted derivatization method facilitates the preparation of FAMEs directly from yeast cells, but the method is likely to also be applicable for other biological samples. PMID:22569641

Khoomrung, Sakda; Chumnanpuen, Pramote; Jansa-ard, Suwanee; Nookaew, Intawat; Nielsen, Jens

2012-06-01

395

Caffeic Acid phenethyl ester: consequences of its hydrophobicity in the oxidative functions and cytokine release by leukocytes.  

PubMed

Numerous anti-inflammatory properties have been attributed to caffeic acid phenethyl ester (CAPE), an active component of propolis. NADPH oxidases are multienzymatic complexes involved in many inflammatory diseases. Here, we studied the importance of the CAPE hydrophobicity on cell-free antioxidant capacity, inhibition of the NADPH oxidase and hypochlorous acid production, and release of TNF-? and IL-10 by activated leukocytes. The comparison was made with the related, but less hydrophobic, caffeic and chlorogenic acids. Cell-free studies such as superoxide anion scavenging assay, triene degradation, and anodic peak potential (E pa) measurements showed that the alterations in the hydrophobicity did not provoke significant changes in the oxidation potential and antiradical potency of the tested compounds. However, only CAPE was able to inhibit the production of superoxide anion by activated leukocytes. The inhibition of the NADPH oxidase resulted in the blockage of production of hypochlorous acid. Similarly, CAPE was the more effective inhibitor of the release of TNF-? and IL-10 by Staphylococcus aureus stimulated cells. In conclusion, the presence of the catechol moiety and the higher hydrophobicity were essential for the biological effects. Considering the involvement of NADPH oxidases in the genesis and progression of inflammatory diseases, CAPE should be considered as a promising anti-inflammatory drug. PMID:25254058

Paracatu, Luana Chiquetto; Faria, Carolina Maria Quinello Gomes; Quinello, Camila; Rennó, Camila; Palmeira, Patricia; Zeraik, Maria Luiza; da Fonseca, Luiz Marcos; Ximenes, Valdecir Farias

2014-01-01

396

Caffeic Acid Phenethyl Ester: Consequences of Its Hydrophobicity in the Oxidative Functions and Cytokine Release by Leukocytes  

PubMed Central

Numerous anti-inflammatory properties have been attributed to caffeic acid phenethyl ester (CAPE), an active component of propolis. NADPH oxidases are multienzymatic complexes involved in many inflammatory diseases. Here, we studied the importance of the CAPE hydrophobicity on cell-free antioxidant capacity, inhibition of the NADPH oxidase and hypochlorous acid production, and release of TNF-? and IL-10 by activated leukocytes. The comparison was made with the related, but less hydrophobic, caffeic and chlorogenic acids. Cell-free studies such as superoxide anion scavenging assay, triene degradation, and anodic peak potential (Epa) measurements showed that the alterations in the hydrophobicity did not provoke significant changes in the oxidation potential and antiradical potency of the tested compounds. However, only CAPE was able to inhibit the production of superoxide anion by activated leukocytes. The inhibition of the NADPH oxidase resulted in the blockage of production of hypochlorous acid. Similarly, CAPE was the more effective inhibitor of the release of TNF-? and IL-10 by Staphylococcus aureus stimulated cells. In conclusion, the presence of the catechol moiety and the higher hydrophobicity were essential for the biological effects. Considering the involvement of NADPH oxidases in the genesis and progression of inflammatory diseases, CAPE should be considered as a promising anti-inflammatory drug. PMID:25254058

Paracatu, Luana Chiquetto; Faria, Carolina Maria Quinello Gomes; Renno, Camila; Palmeira, Patricia; da Fonseca, Luiz Marcos; Ximenes, Valdecir Farias

2014-01-01

397

Preparation, mechanical property and cytocompatibility of poly(L-lactic acid)/calcium silicate nanocomposites with controllable distribution of calcium silicate nanowires.  

PubMed

How to accurately control the microstructure of bioactive inorganic/organic nanocomposites still remains a significant challenge, which is of great importance in influencing their mechanical strength and biological properties. In this study, using a combined method of electrospinning and hot press processing, calcium silicate hydrate (CSH) nanowire/poly(L-lactide) (PLLA) nanocomposites with controllable microstructures and tailored mechanical properties were successfully prepared as potential bone graft substitutes. The electrospun hybrid nanofibers with various degrees of alignment were stacked together in a predetermined manner and hot pressed into hierarchically structured nanocomposites. The relationship between the microstructure and mechanical properties of the as-prepared nanocomposites were systematically evaluated. The results showed that CSH nanowires in a PLLA matrix were able to be controlled from completely randomly oriented to uniaxially aligned, and then hierarchically organized with different interlayer angles, leading to corresponding nanocomposites with improved mechanical properties and varied anisotropies. It was also found that the bending strength of nanocomposites with 5 wt.% CSH nanowires (130 MPa) was significantly higher than that of pure PLLA (86 MPa) and other composites. The addition of CSH nanowires greatly enhanced the hydrophilicity and apatite-forming ability of PLLA films, as well as the attachment and proliferation of bone marrow stromal cells. The study suggested that a combination of electrospinning and hot pressing is a viable means to control the microstructure and mechanical properties, and improve the mineralization ability and cellular responses, of CSH/PLLA nanocomposites for potential bone repair applications. PMID:22813849

Dou, Yuandong; Wu, Chengtie; Chang, Jiang

2012-11-01

398

Testing for ethanol markers in hair: Discrepancies after simultaneous quantification of ethyl glucuronide and fatty acid ethyl esters.  

PubMed

The hair of 97 cases were analysed for ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE, including ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) according to the Society of Hair Testing guidelines to examine the role of both tests in documenting chronic excessive alcohol drinking, particularly when the results are in contradiction. 27 (27.8%) results were EtG negative and FAEE positive, when applying the SoHT cut-offs, probably due to the use of alcohol-containing hair products. Four cases (4.1%) were EtG positive and FAEE negative that were attributed to the use of herbal lotions containing EtG. PMID:24794020

Kintz, P; Nicholson, D

2014-10-01

399

Catalyst-free fatty acid methyl ester production from wet activated sludge under subcritical water and methanol condition.  

PubMed

Wet activated sludge was converted directly into biodiesel using water as hydrolysis reagent to enhance the extraction of lipid in activated sludge, and as catalyst for the conversion of neutral lipids into biodiesel under subcritical conditions. At 175°C, 3.5MPa, a methanol to sludge ratio of 30 (mL/g) and a sludge water content of 84wt.%, about 90% conversion to fatty acid methyl esters was achieved within 24h without the need for conventional catalysts such as KOH and H(2)SO(4). Since water is employed as a catalyst, its removal is not required; therefore, the processing costs for producing biodiesel from activated sludge are reduced. The method has the potential for applications to other feedstock with high water contents such as micro-algae. PMID:22940307

Huynh, Lien Huong; Tran Nguyen, Phuong Lan; Ho, Quoc Phong; Ju, Yi-Hsu

2012-11-01

400

Effect of caffeic acid phenethyl ester on survival of axial pattern flaps in rats with ischaemia-reperfusion injuries.  

PubMed

Oxygen-derived free radicals have been implicated in the pathogenesis of tissue injury after ischaemia-reperfusion. Caffeic acid phenethyl ester (CAPE), an active ingredient of honeybee propolis, has been identified as having potent antioxidant and anti-inflammatory properties. We evaluated the ability of CAPE applied intraperitoneally in reducing tissue injury after ischaemia-reperfusion. To investigate whether treatment with CAPE modifies the concentrations of the endogenous indices of oxidant stress, we examined its effects on a model of flap ischaemia-reperfusion injury in rats. CAPE (10 micromol/kg) was given through the peritoneum before reperfusion. CAPE given intraperitoneally had an inhibitory effect on tissue injury after ischaemia-reperfusion comparable to that of a control group. The anti-inflammatory and antioxidant properties of CAPE may contribute to its suppression of tissue injury. PMID:16537252

Bilen, Bilge Türk; Kilinç, Hidir; Alaybeyoglu, Nezih; Celik, Mehmet; Iraz, Mustafa; Sezgin, Nurzen; Gültek, Ahmet

2006-01-01

401

The biocide tributyltin reduces the accumulation of testosterone as fatty acid esters in the mud snail (Ilyanassa obsoleta).  

PubMed Central

Imposex, the development of male sex characteristics by female gonochoristic snails, has been documented globally and is causally associated with exposure to the ubiquitous environmental contaminant tributyltin (TBT). Elevated testosterone levels in snails also are associated with TBT, and direct exposure to testosterone has been shown to cause imposex. We discovered previously that the mud snail (Ilyanassa obsoleta)biotransforms and retains excess testosterone primarily as fatty acid esters. The purpose of this study was to determine whether TBT interferes with the esterification of testosterone, resulting in the elevated free (unesterified) testosterone levels associated with imposex. Exposure of snails to environmentally relevant concentrations of TBT (> or = 1.0 ng/L as tin) significantly increased the incidence of imposex. Total (free + esterified) testosterone levels in snails were not altered by TBT; however, free testosterone levels increased with increasing exposure concentration of TBT. TBT-exposed snails were given [14C

Gooding, Meredith P; Wilson, Vickie S; Folmar, Leroy C; Marcovich, Dragoslav T; LeBlanc, Gerald A

2003-01-01

402

Structural and spectroscopic studies of a new 2-naphthylmethyl ester of lasalocid acid  

NASA Astrophysics Data System (ADS)

A new lasalocid 2-naphthylmethyl ester (NAFB) has been synthesised and studied by X-ray, 1H NMR, 13C NMR, FT-IR, UV-vis, fluorescence-spectroscopy as well as by the PM5 semiempirical method. The crystals of NAFB are monoclinic, space group P2 1 with a = 10.120(2) Å, b = 18.245(3) Å, c = 12.354(3) Å, ? = 109.65(3)? and Z = 2. The molecular conformation of NAFB in the solid state is stabilized by three intramolecular hydrogen bonds, and no intermolecular H-bonds are formed. The FT-IR spectrum of NAFB in chloroform indicates equilibrium between two NAFB conformers. In the first conformer the keto group forms an intramolecular hydrogen bond, while in the second one this group is not involved in any hydrogen bonds. The two structures of NAFB are calculated by the PM5 method and discussed in detail.

Huczy?ski, Adam; Paluch, Izabela; Ratajczak-Sitarz, Ma?gorzata; Katrusiak, Andrzej; Brzezinski, Bogumil; Bartl, Franz

2009-01-01

403

Very long chain fatty acid methyl esters in transesterified palm oil.  

PubMed

Some unidentified minor compounds have been observed in the residue from short-path distillation of transesterified palm oil that are not detected in the original palm oil. A method combining short-path distillation to enrich the unknowns with fractionation using solid-phase extraction is described. The fractionated components were identified using GC coupled with MS. The transesterified palm oil was found to contain methyl esters of up to C32 carbon atoms. In the very long chain FAME with carbon numbers > or = 20, both even and odd carbon numbers accounted for 0.26 wt%, with C24 and C26 being the major ones present in the residue after short-path distillation of transesterified palm oil. PMID:16711607

Puah, Chiew Wei; Choo, Yuen May; Ma, Ah Ngan; Chuah, Cheng Hock

2006-03-01

404

40 CFR 721.8350 - 2-Propenoic acid, 7-oxa-bi-cy-clo[4.1.0]hept-3-ylmethyl ester.  

Code of Federal Regulations, 2010 CFR

(1) The chemical substance 2-propenoic acid, 7-oxabicyclo[4.1.0]hept-3-ylmethyl ester (PMN P-89-31) is subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this section. (2) The significant new uses are: (i) Protection in the...

2010-07-01

405

Switchable reactivity of acylated alpha, beta-dehydroamino ester in the Friedel-Crafts alkylation of indoles by changing the Lewis acid.  

PubMed

Highly regioselective electrophilic substitution of indoles with N-acetylated alpha,beta-dehydroalanine methyl ester, promoted by different transition metal salts was achieved. The orthogonal regioselectivity provides an efficient protocol toward highly functionalized 3-indolyl-alpha-amino acids. The mechanism of the reactions was explored by NMR studies. PMID:18558761

Angelini, Elena; Balsamini, Cesarino; Bartoccini, Francesca; Lucarini, Simone; Piersanti, Giovanni

2008-07-18

406

Rapid analysis of phthalic acid esters in environmental water using fast elution gas chromatography with mass spectrometry and adaptive library spectra.  

PubMed

A method for the fast determination of the components in a complex sample by using gas chromatography with mass spectrometry was developed and used for the quantitative analysis of phthalic acid esters in environmental water. In the method, the adaptively corrected mass spectra were used to compensate for the differences between the library spectra and the measured ones in the experiment. The correction was obtained by the iterative transformation of the library spectra using iterative target transformation factor analysis, and the resolution was performed by non-negative immune algorithm using the corrected spectra. Rapid analysis of 16 phthalic acid esters in water samples was achieved using fast elution gas chromatography with mass spectrometry measurements. The results show that the mass spectra and chromatographic profiles of the phthalic acid esters can be obtained from the overlapping signal of 13 min elution, and accurate quantitative analysis can be obtained. The recoveries of the phthalic acid esters obtained by standard addition are between 90.3 and 107.4%, and the relative standard deviations obtained in repeated measurements are less than 9%. PMID:24737593

Li, Pao; Mei, Zhen; Cai, Wensheng; Shao, Xueguang

2014-07-01

407

Effect of hair care and hair cosmetics on the concentrations of fatty acid ethyl esters in hair as markers of chronically elevated alcohol consumption  

Microsoft Academic Search

Fatty acid ethyl esters (FAEE) can be used as alcohol markers in hair. It was investigated in this study whether this diagnostic method is disturbed by hair care and hair cosmetics. Traces of ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate were detected in all of 49 frequently applied hair care products by headspace solid phase microextraction (HS-SPME) and

Sven Hartwig; Volker Auwärter; Fritz Pragst

2003-01-01

408

Practical experiences in application of hair fatty acid ethyl esters and ethyl glucuronide for detection of chronic alcohol abuse in forensic cases  

Microsoft Academic Search

This article presents results from 1872 hair samples, which were analyzed for fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG). The results were evaluated in the context of self-reported drinking behavior, the use of hair cosmetics, the gender of the sample donors and hair sample length. For comparison, CDT and GGT in serum were available in 477 and 454

S. Suesse; F. Pragst; T. Mieczkowski; C. M. Selavka; A. Elian; H. Sachs; M. Hastedt; M. Rothe; J. Campbell

409

Optimization of transesterification conditions for the production of fatty acid methyl ester (FAME) from Chinese tallow kernel oil with surfactant-coated lipase  

Microsoft Academic Search

Surfactant-coated lipase was used as a catalyst in preparing fatty acid methyl ester (FAME) from Chinese tallow kernel oil from Sapium sebiferum (L.) Roxb. syn. Triadica sebifera (L.) small. FAME transesterification was analyzed using response surface methodology to find out the effect of the process variables on the esterification rate and to establish prediction models. Reaction temperature and time were

Yin-yu Gao; Wen-wei Chen; Hanwu Lei; Yuhuan Liu; Xiangyang Lin; Roger Ruan

2009-01-01

410

Depression and adipose and serum cholesteryl ester polyunsaturated fatty acids in the survivors of the seven countries study population of Crete  

Microsoft Academic Search

BACKGROUND: Studies have shown that depression relates to biomarkers of both short- and long-term polyunsaturated fatty acid (PUFA) intake. However, it is not known which of these two biomarkers has the closest relationship to depression. OBJECTIVE: To examine the relationship of depression with both adipose tissue and serum cholesteryl ester PUFA and to assess the importance of each of these

G Mamalakis; E Jansen; H Cremers; M Kiriakakis; G Tsibinos; A Kafatos

2007-01-01

411

TERATOLOGY AND POSTNATAL STUDIES IN RATS OF THE PROPYLENE GLYCOL BUTYL ETHER AND ISOOCTYL ESTERS OF 2,4-DICHLOROPHENOXYACETIC ACID  

EPA Science Inventory

The purpose of this study was to evaluate the teratogenic potential of the propylene glycol butyl ether (PGBE) and isooctyl (IO) esters of 2,4-dichlorophenoxyacetic acid (2,4-D). Accordingly, groups of pregnant CD rats received daily oral doses of PGBE or IO equivalent to 0, 6.25...

412

Functional Co-substituted Poly[(amino acid ester)phosphazene] Biomaterials.  

E-print Network

??The development of new and improved biomaterials is essential for tissue engineering and regenerative medicine applications. Amino acid-based polyphosphazenes are being explored as scaffold materials… (more)

Baillargeon, Amanda L

2014-01-01

413

Effects of Prescription Omega-3-Acid Ethyl Esters on Non--High-Density Lipoprotein Cholesterol When Coadministered With Escalating Doses of Atorvastatin  

PubMed Central

OBJECTIVE: To evaluate the effects of prescription omega-3-acid ethyl esters on non—high-density lipoprotein cholesterol (HDL-C) levels in atorvastatin-treated patients with elevated non—HDL-C and triglyceride levels. PATIENTS AND METHODS: This study, conducted between February 15, 2007, and October 22, 2007, randomized patients with elevated non—HDL-C (>160 mg/dL) and triglyceride (?250 mg/dL and ?599 mg/dL) levels to double-blind treatment with prescription omega-3-acid ethyl esters, 4 g/d, or placebo for 16 weeks. Patients also received escalating dosages of open-label atorvastatin (weeks 0-8, 10 mg/d; weeks 9-12, 20 mg/d; weeks 13-16, 40 mg/d). RESULTS: Prescription omega-3-acid ethyl esters plus atorvastatin, 10, 20, and 40 mg/d, reduced median non—HDL-C levels by 40.2% vs 33.7% (P<.001), 46.9% vs 39.0% (P<.001), and 50.4% vs 46.3% (P<.001) compared with placebo plus the same doses of atorvastatin at the end of 8, 12, and 16 weeks, respectively. Prescription omega-3-acid ethyl esters plus atorvastatin also reduced median total cholesterol, triglyceride, and very low-density lipoprotein cholesterol levels and increased HDL-C levels to a significantly greater extent than placebo plus atorvastatin. Percent changes from baseline low-density lipoprotein-cholesterol, apolipoprotein A-I, and apolipoprotein B levels were not significantly different between groups at the end of the study. CONCLUSION: Prescription omega-3-acid ethyl esters plus atorvastatin produced significant improvements in non—HDL-C and other lipid parameters in patients with elevated non—HDL-C and triglyceride levels. PMID:20118387

Bays, Harold E.; McKenney, James; Maki, Kevin C.; Doyle, Ralph T.; Carter, Roderick N.; Stein, Evan

2010-01-01

414

New entry for synthesis of N-acylhydrazones, pyridazinones, and 1,3,4-oxadiazin-6-ones from alpha-amino acid esters.  

PubMed

Versatile electrophiles N-acylhydrazones are synthesized via diazotization, reduction, and acylation of alpha-amino acid esters. Reduction of diazo esters with L-selectride or tributylphosphine affords the corresponding hydrazones in good yields. Both reducing agents give anti-hydrazones as the major product although the reactivity of each reductant is slightly different. The resulting hydrazones are acylated to give N-acylhydrazones, which are subjected to further reactions to give 1,3,4-oxadiazin-6-ones that serve as useful synthetic intermediates for the Diels-Alder reaction. PMID:17978531

Yasui, Eiko; Wada, Masao; Takamura, Norio

2007-11-01

415

Isolation of interleukin 2 (IL-2) from human and mouse lymphocyte culture supernatants by batch adsorption onto silicic acid.  

PubMed

Described herein is a simple, efficient and inexpensive batch adsorption procedure for the isolation and partial purification of the hydrophobic T cell growth-promoting lymphokine interleukin 2 (IL-2) from crude culture supernatants (SN) of freshly isolated human lymphocytes and leukemic T cells of established lines including human Jurkat J6.2, Gibbon ape MLA-144 and mouse EL-4. In this method, IL-2 was isolated by batch adsorption onto microparticulate silicic acid (SA) by stir-mixing the SA with SN (10 mg/ml; 30 min; 37 degrees C). Thereafter, the SA was pelleted by centrifugation and washed twice with phosphate-buffered saline (PBS). The IL-2 was eluted by adding to the pelleted IL-2-binding SA 5 vols. of ethylene glycol (EG; 50%, v/v) in PBS (pH 7.2) with high salt (1.4 M NaCl). The lymphokine-rich concentrate was then dialyzed (6 kDa MWCO) against PBS to remove the EG and low molecular weight growth inhibitors. The application of the proposed procedure was further defined in experiments in which SA was successfully employed for recovering IL-2 from SN of cultures in which the medium had been supplemented with fetal calf (FCS) or human serum to achieve maximal lymphokine production. Also presented are the results of experiments defining the SA adsorption of proteins from whole sera (e.g., FCS, calf, human and horse) and the relative affinity of different purified proteins for this matrix (e.g., bovine serum albumin, human serum albumin, casein hydrolysate, bovine gamma-globulin and bovine beta-lactoglobulin). The proposed SA procedure may prove useful for isolating other hydrophobic immunoregulatory molecules, and a 2-step purification scheme is anticipated in which the SA adsorption procedure will be used as a preparative method preceding reverse phase high performance liquid chromatography and monoclonal antibody affinity chromatography. PMID:6096448

Pauly, J L; Ovak, G M; Russell, C W

1984-12-14

416

Accurate and Reliable Quantification of Total Microalgal Fuel Potential as Fatty Acid Methyl Esters by in situ Transesterfication  

SciTech Connect

In the context of algal biofuels, lipids, or better aliphatic chains of the fatty acids, are perhaps the most important constituents of algal biomass. Accurate quantification of lipids and their respective fuel yield is crucial for comparison of algal strains and growth conditions and for process monitoring. As an alternative to traditional solvent-based lipid extraction procedures, we have developed a robust whole-biomass in situ transesterification procedure for quantification of algal lipids (as fatty acid methyl esters, FAMEs) that (a) can be carried out on a small scale (using 4-7 mg of biomass), (b) is applicable to a range of different species, (c) consists of a single-step reaction, (d) is robust over a range of different temperature and time combinations, and (e) tolerant to at least 50% water in the biomass. Unlike gravimetric lipid quantification, which can over- or underestimate the lipid content, whole biomass transesterification reflects the true potential fuel yield of algal biomass. We report here on the comparison of the yield of FAMEs by using different catalysts and catalyst combinations, with the acid catalyst HCl providing a consistently high level of conversion of fatty acids with a precision of 1.9% relative standard deviation. We investigate the influence of reaction time, temperature, and biomass water content on the measured FAME content and profile for 4 different samples of algae (replete and deplete Chlorella vulgaris, replete Phaeodactylum tricornutum, and replete Nannochloropsis sp.). We conclude by demonstrating a full mass balance closure of all fatty acids around a traditional lipid extraction process.

Laurens, L. M. L.; Quinn, M.; Van Wychen, S.; Templeton, D. W.; Wolfrum, E. J.

2012-04-01

417

Determination of C 1 ?C 4 fatty acids as p-bromophenacyl esters using glass-capillary gas chromatography and electron-capture detection  

Microsoft Academic Search

Summary  A method for the determination of low relative molecular mass carboxylic acids (C1–C4) in water is reported. The acids are converted to p-bromophenacyl esters prior to a glass-capillary gas chromatographic separation. By utilizing electron-caputre detection the detectability is substantially improved compared to flame-ionization detection. A comparison of three different ways to treat the water samples and to produce the derivatives

M. Larsson; C. Roos

1983-01-01

418

Fluorinative hydrolysis of phosphorothioic acid esters with a binaphthyl group through axis-to-center chirality transfer leading to the formation of P-chiral phosphorothioic monofluoridic acid salts.  

PubMed

Asymmetric synthesis of P-chiral phosphorothioic monofluoridic acid ammonium salts was achieved via axis-to-center chirality transfer reactions by using phosphorothioic acid O-esters with a binaphthyl group, and the absolute stereochemistry of the salts was determined by X-ray analyses and by comparison of their CD spectra. PMID:25195782

Murai, Toshiaki; Hayashi, Takae; Yamada, Kyohei; Maekawa, Yuuki; Minoura, Mao

2014-09-18

419

Difference in substrate specificity between human and mouse lysosomal acid lipase: low affinity for cholesteryl ester in mouse lysosomal acid lipase.  

PubMed

Lysosomal acid lipase (LAL) is essential for the intracellular degradation of cholesteryl esters (CE) and triacylglycerols (TG) that are delivered to lysosomes by low density lipoprotein (LDL) receptor mediated endocytosis. We have analysed the difference in the catalytic properties and substrate specificity of human and mouse LALs. LAL activities were measured in human and mouse fibroblasts and in HeLa cells transiently expressing wild-type or site-directed mutant LALs of the two species using the T7 vaccinia system. Cholesteryl esterase and triacylglycerol lipase activities were determined in cellular homogenates with a phospholipid/detergent vesicle assay, an assay frequently used to diagnose human LAL deficiency syndromes, and with LDL particles, a more physiological substrate. Characterisation of human and mouse LAL using these two assays demonstrated marked differences in their TG and CE hydrolysing activities. Compared to human LAL mouse LAL showed a much lower cholesteryl esterase activity in both assays used. The difference was more pronounced in the vesicle assay. The lower cholesteryl esterase activity of mouse LAL did not affect the LDL-CE degradation in intact fibroblasts. The analysis of site-directed mutants suggests a role of the non-conserved cysteine residue at position 240 in cholesteryl esterase activity in human LAL. Our results show a significant difference between human and mouse LAL in their specificity toward cholesteryl esters. The low cholesteryl esterase activity does not result in reduced LDL-cholesterol ester degradation in mouse fibroblasts in situ. In addition, this work emphasises the importance of the physical state of substrates in studies of the specificity and properties of lipolytic enzymes. PMID:11018468

Groener, J E; Bax, W; Stuani, C; Pagani, F

2000-09-27

420

Production and characterization of methyl ester sophorolipids with 22-carbon-fatty acids.  

PubMed

In this study, various fatty acids of 18 and 22 carbons were used as substrates to produce sophorolipids in Candida bombicola ATCC 22214. Methyl esterification of erucic acid and C22-enriched rapeseed oil generated mainly acidic sophorolipids with different degrees of saturation in the fatty acid chain, which was demonstrated by structural analysis using HPLC, LC-MS and NMR spectroscopy. Regardless of methyl esterification, the rapeseed oil served as the best substrate for high production of sophorolipids among the tested. Methyl esterification also had no noticeable effect on the interfacial properties of sophorolipids. However, 22 carbons introduced in the fatty acid chain increased the hydrophobicity of sophorolipids, and therefore improved surface-active properties and biodegradability. PMID:20053555

Shin, Jae Dong; Lee, Jeongmi; Kim, Yong Bum; Han, In-Sun; Kim, Eun-Ki

2010-05-01

421

The effects of solvent mixtures on the gel permeation chromatography of alkanes, fatty acids, and fatty acid esters  

E-print Network

of the samples in the different solvents was calculated using Equation 2. (41). 22828 Ol Z O O III e QJ O e K e e K Ill e c o e ID IA O 0 rO o o e 0 e e e o e 4J QJ Cl e e CI O O e e &( Cl 22 26 28 3B 32 34 36 38 &B MINUTES Figure 1... III U 4J O O QJ O III lll O III 5356 O W Ill Ill E E 4J O Ill E E ze 22 24 26 28 38 32 34 36 38 'le l1IMUTES Figure 3. GPC chromatogram of a series of methyl esters in THF. 28277 N Z 0 0 CU IO CU CU 0 CUBIC-I C CU IU IU CU IU IU...

Bolton, Patrick Lee

2012-06-07

422

High-yield preparation of wax esters via lipase-catalyzed esterification using fatty acids and alcohols from crambe and camelina oils.  

PubMed

Fatty acids obtained from seed oils of crambe (Crambe abyssinica) and camelina (Camelina sativa) via alkaline saponification or steam splitting were esterified using lipases as biocatalysts with oleyl alcohol and the alcohols derived from crambe and camelina oils via hydrogenolysis of their methyl esters. Long-chain wax esters were thus obtained in high yields when Novozym 435 (immobilized lipase B from Candida antarctica) and papaya (Carica papaya) latex lipase were used as biocatalysts and vacuum was applied to remove the water formed. The highest conversions to wax esters were obtained with Novozym 435 (> or =95%) after 4-6 h of reaction, whereas with papaya latex lipase such a high degree of conversion was attained after 24 h. Products obtained from stoichiometric amounts of substrates were almost exclusively (>95%) composed of wax esters having compositions approaching that of jojoba (Simmondsia chinensis) oil, especially when crambe fatty acids in combination with camelina alcohols or camelina fatty acids in combination with crambe alcohols were used as substrates. PMID:11262006

Steinke, G; Weitkamp, P; Klein, E; Mukherjee, K D

2001-02-01

423

Synthetic resin-bound truncated Candida antarctica lipase B for production of fatty acid alkyl esters by transesterification of corn and soybean oils with ethanol or butanol.  

PubMed

A gene encoding a synthetic truncated Candida antarctica lipase B (CALB) was generated via automated PCR and expressed in Saccharomyces cerevisiae. Western blot analysis detected five truncated CALB variants, suggesting multiple translation starts from the six in-frame ATG codons. The longest open reading frame, which corresponds to amino acids 35-317 of the mature lipase, appeared to be expressed in the greatest amount. The truncated CALB was immobilized on Sepabeads® EC-EP resin and used to produce ethyl and butyl esters from crude corn oil and refined soybean oil. The yield of ethyl esters was 4-fold greater from corn oil than from soybean oil and was 36% and 50% higher, respectively, when compared to a commercially available lipase resin (Novozym 435) using the same substrates. A 5:1 (v/v) ratio of ethanol to corn oil produced 3.7-fold and 8.4-fold greater yields than ratios of 15:1 and 30:1, respectively. With corn oil, butyl ester production was 56% higher than ethyl ester production. Addition of an ionic catalytic resin step prior to the CALB resin increased yields of ethyl esters from corn oil by 53% compared to CALB resin followed by ionic resin. The results suggest resin-bound truncated CALB has potential application in biodiesel production using biocatalysts. PMID:22342374

Hughes, Stephen R; Moser, Bryan R; Robinson, Samantha; Cox, Elby J; Harmsen, Amanda J; Friesen, Jon A; Bischoff, Kenneth M; Jones, Marjorie A; Pinkelman, Rebecca; Bang, Sookie S; Tasaki, Ken; Doll, Kenneth M; Qureshi, Nasib; Liu, Siqing; Saha, Badal C; Jackson, John S; Cotta, Michael A; Rich, Joseph O; Caimi, Paolo

2012-05-31

424

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

Code of Federal Regulations, 2013 CFR

...percent; and acid number, 12 maximum. (c) It is used in amounts not in excess of that reasonably required to produce the intended physical effect as an emulsifier, plasticizer, or surface-active agent in...

2013-04-01

425

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

Code of Federal Regulations, 2012 CFR

...percent; and acid number, 12 maximum. (c) It is used in amounts not in excess of that reasonably required to produce the intended physical effect as an emulsifier, plasticizer, or surface-active agent in...

2012-04-01

426

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

Code of Federal Regulations, 2011 CFR

...percent; and acid number, 12 maximum. (c) It is used in amounts not in excess of that reasonably required to produce the intended physical effect as an emulsifier, plasticizer, or surface-active agent in...

2011-04-01

427

A novel continuous flow biosynthesis of caffeic acid phenethyl ester from alkyl caffeate and phenethanol in a packed bed microreactor.  

PubMed

Caffeic acid phenethyl ester (CAPE) is a rare natural ingredient with several biological activity, but the industrial production of CAPE using lipase-catalyzed esterification of caffeic acid (CA) and 2-phenylethanol (PE) in ionic liquids is hindered by low substrate concentrations and a long reaction time. To establish a high-efficiency bioprocess for obtaining CAPE, a novel continuous flow biosynthesis of CAPE from alkyl caffeate and PE in [Bmim][Tf2N] using a packed bed microreactor was successfully carried out. Among the tested alkyl caffeates and lipases, methyl caffeate and Novozym 435, respectively, were selected as the suitable substrate and biocatalyst. Under the optimum conditions selected using response surface methodology, a 93.21% CAPE yield was achieved in 2.5h using a packed bed microreactor, compared to 24h using a batch reactor. The reuse of Novozym 435 for 20 cycles and continuous reaction for 9 days did not result in any decrease in activity. PMID:24583213

Wang, Jun; Gu, Shuang-Shuang; Cui, Hong-Sheng; Wu, Xiang-Yang; Wu, Fu-An

2014-04-01

428

Hydroxycinnamoyltransferases Involved in the Accumulation of Caffeic Acid Esters in Gametophytes and Sporophytes of Equisetum arvense.  

PubMed

Four hydroxycinnamoyltransferases from Equisetum arvense L. were studied that catalyze the formation of mono-O-caffeoyl-meso-tartrate, di-O-caffeoyl-meso-tartrate, 5-O-caffeoylshikimate (dactylifrate), and 5-O-caffeoylquinate (chlorogenate). The enzymes were classified as coenzyme A (CoA)-ester-dependent acyltransferases (EC 2.3.1), i.e. hydroxycinnamoyl-CoA:meso-tartrate hydroxycinnamoyltransferase (CTT), hydroxycinnamoyl-CoA:caf-feoyl-meso-tartrate hydroxycinnamoyltransferase (CCT), hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (CST), and hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase. The CTT, CCT, and CST were partially purified and separated from E. arvense gametophytes by hydrophobic interaction chromatography on Fractogel TSK Butyl-650 followed by molecular exclusion on fast protein liquid chromatography-Superdex-75 with 87-, 62-, and 130- fold enrichments and 12, 8, and 11% yields, respectively. The enzyme activities obtained with caffeoyl-CoA were 95 (CTT), 74 (CCT), and 200 [mu]kat (CST) kg-1 protein. The apparent native relative molecular weight values were found to be approximately 45,000 (CTT), 52,000 (CCT), and 50,000 (CST). Each enzyme showed highest activities at pH 7.5, the CCT and CST in Tris-HCl (1.2 and 1.0 M) and the CTT in imidazole-HCl (1.25 M). Enzyme activities were stimulated more than 3-fold by 100 mM ascorbate. The apparent energies of activation (kilojoules mol-1) were calculated to be 56 (CTT), 69 (CST), and 76 (CCT). The enzymes accepted cinnamoyl-CoA and various hydroxycinnamoyl-CoAs. The time course of the transferase activities along with that of a fourth one, hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase, and the pattern of product accumulation were determined during a 1-year growth period of the E. arvense sporophytes. PMID:12226354

Hohlfeld, M.; Veit, M.; Strack, D.

1996-08-01

429

Metabolism of arachidonic acid in phorbol ester, interferon and dimethyl sulfoxide differentiation induced U937 cells  

SciTech Connect

U937, a human macrophage cell line can metabolize arachidonic acid to a prostaglandin E2-like substance, and an unidentified lipoxygenase product. This metabolism occurs at very low levels however since these cells have low lipase and fatty acid oxygenase activities. The investigated the appearance of these enzyme activities during differentiation induced by phorbol-12-myristate-13-acetate (PMA), human gamma interferon (INF), and dimethyl sulfoxide (DMSO) on days 1,3 and 5 of stimulation using /sup 3/H-arachidonic acid (/sup 3/H-AA). Culture supernatants were analyzed for free /sup 3/H-AA and /sup 3/H metabolites by radio-thin layer chromatography (/sup 3/H-MET). The increasing percentage of /sup 3/H-AA release suggests the appearance of phospholipase activity during differentiation.

Ou, D.W.; Wiederhold, M.D.

1986-03-05

430

Clinical Effect and Safety Profile of Recombinant Human Lysosomal Acid Lipase in Patients with Cholesteryl Ester Storage Disease  

PubMed Central

Background & Aims Cholesteryl Ester Storage Disease, an inherited deficiency of lysosomal acid lipase, is an underappreciated cause of progressive liver disease with no approved therapy. Presenting features include dyslipidemia, elevated transaminases, and hepatomegaly. Methods To assess the clinical effects and safety of the recombinant human lysosomal acid lipase, sebelipase alfa, 9 patients received 4 once-weekly infusions (0.35, 1, or 3 mg·kg?1) in LAL-CL01 which is the first human study of this investigational agent. Patients completing LAL-CL01 were eligible to enroll in the extension study (LAL-CL04) in which they again received 4 once-weekly infusions of sebelipase alfa (0.35, 1, or 3 mg·kg?1) before transitioning to long term every other week infusions (1 or 3 mg·kg?1). Results Sebelipase alfa was well-tolerated with mostly mild adverse events unrelated sebelipase alfa. No anti-drug antibodies were detected. Transaminases decreased in patients in LAL-CL01 and increased between studies. In 7 patients receiving ongoing sebelipase alfa treatment in LAL-CL04, mean±SD decreases for alanine transaminase and aspartate aminotransferase at week 12 compared to the baseline values in LAL-CL01 were 46±21U/L (-52%) and 21±14U/L (-36%), respectively (p<0.05). Through week 12 of LAL-CL04, these 7 patients also showed mean decreases from baseline in total cholesterol of 44±41mg/dL (-22%; p=0.047), low density lipoprotein-cholesterol of 29±31mg/dL (-27%; p=0.078), and triglycerides of 50±38mg/dL (-28%, p=0.016) and increases in high density lipoprotein-cholesterol of 5mg/dL (15%; p=0.016). Conclusions These data establish that sebelipase alfa, an investigational enzyme replacement, in patients with Cholesteryl Ester Storage Disease is well tolerated, rapidly decreases serum transaminases and that these improvements are sustained with long term dosing and are accompanied by improvements in serum lipid profile. PMID:23348766

Balwani, Manisha; Breen, Catherine; Enns, Gregory M; Deegan, Patrick B; Honzik, Tomas; Jones, Simon; Kane, John P; Malinova, Vera; Sharma, Reena; Stock, Eveline O; Valayannopoulos, Vassili; Wraith, J Edmond; Burg, Jennifer; Eckert, Stephen; Schneider, Eugene; Quinn, Anthony G

2013-01-01

431

Study on analysis of waste edible oil with deterioration and removal of acid value, carbonyl value, and free fatty acid by a food additive (calcium silicate).  

PubMed

This study investigated the regeneration of waste edible oil using a food additive (calcium silicate, CAS). Waste edible oil was prepared by combined heat and aeration treatment. Moreover, the deterioration of edible oil by combined heat and aeration treatment was greater than that by heat treatment alone. The acid value (AV) and carbonyl value (CV) increased with increasing deterioration; conversely, the tocopherol concentration decreased with increasing deterioration. The specific surface area, pore volume, and mean pore diameter of the 3 CAS formulations used (CAS30, CAS60, and CAS90) were evaluated, and scanning electron microscopic images were taken. The specific surface area increased in the order of CAS30 (115.54 m(2)/g) < CAS60 (163.93 m(2)/g) < CAS90 (187.47 m(2)/g). The mean pore diameter increased in the order of CAS90 (170.59 Å) < CAS60 (211.60 Å) < CAS30 (249.70 Å). The regeneration of waste edible oil was possible with CAS treatment. The AV reduced by 15.2%, 10.8%, and 23.1% by CAS30, CAS60, and CAS90 treatment, respectively, and the CV was reduced by 35.6%, 29.8%, and 31.3% by these 3 treatments, respectively. Moreover, the concentrations of tocopherol and free fatty acids did not change with CAS treatment. The characteristics of CAS were not related to the degree of change of AV and CV. However, the adsorption mechanism of polar and non-polar compounds generated in waste edible oil by CAS was related with the presence of silica gel molecules in CAS. The findings indicated that CAS was useful for the regeneration of waste edible oil. PMID:23391535

Ogata, Fumihiko; Tanaka, Yuko; Tominaga, Hisato; Kangawa, Moe; Inoue, Kenji; Ueda, Ayaka; Iwata, Yuka; Kawasaki, Naohito

2013-01-01

432

Highly efficient enzymatic synthesis of an ascorbyl unstaturated fatty acid ester with ecofriendly biomass-derived 2-methyltetrahydrofuran as cosolvent.  

PubMed

Enzymatic synthesis of ascorbyl undecylenate, an unsaturated fatty acid ester of ascorbic acid, was reported with biomass-derived 2-methyltetrahydrofuran (MeTHF) as the cosolvent. Of the immobilized lipases tested, Candida antarctica lipase B (CAL-B) showed the highest activity for enzymatic synthesis of ascorbyl undecylenate. Effect of reaction media on the enzymatic reaction was studied. The cosolvent mixture, t-butanol-MeTHF (1:4, v/v) proved to be the optimal medium, in which not only ascorbic acid had moderate solubility, but also CAL-B showed a high activity, thus addressing the major problem of the solvent conflict for dissolving substrate and keeping satisfactory enzyme activity. In addition, the enzyme was much more stable in MeTHF and t-butanol-MeTHF (1:4) than in previously widely used organic solvents, t-butanol, 2-methyl-2-butanol, and acetone. The much higher initial reaction rate in this cosolvent mixture may be rationalized by the much lower apparent activation energy of this enzymatic reaction (26.6 vs. 38.1-39.1 kJ/mol) and higher enzyme catalytic efficiency (Vmax /Km , 8.4 vs. 1.3-1.4 h(-1) ). Ascorbyl undecylenate was obtained with the yields of 84-89% and 6-regioselectivity of >99% in t-butanol-MeTHF (1:4) at supersaturated substrate concentrations (60 and 100 mM) after 5-8 h. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1005-1011, 2014. PMID:24891225

Hu, Ying-Dan; Qin, Ye-Zhi; Li, Ning; Zong, Min-Hua

2014-09-01

433

Determination of methyl and ethyl esters of methanesulfonic, benzenesulfonic and p-toluenesulfonic acids in active pharmaceutical ingredients by solid-phase microextraction (SPME) coupled to GC\\/SIM-MS  

Microsoft Academic Search

The development, optimization and validation of an extraction method for methyl and ethyl esters of various sulfonic acids is presented. The extraction and determination of these esters in active pharmaceutical ingredients (APIs) was accomplished using solid-phase microextraction coupled to GC\\/MS in the SIM mode. The factors affecting the extraction efficiency are discussed. This method was validated as a limits test

Ivelisse Colón; Stephen M. Richoll

2005-01-01

434

Studies on the Separation and Recovery of Thorium from Nitric Acid Medium using (2-ethyl hexyl) Phosphonic Acid, Mono (2-ethyl hexyl) Ester (PC88A)\\/N-Dodecane as Extractant System  

Microsoft Academic Search

This paper deals with the studies on the separation and recovery of thorium and 233-uranium from nitric acid medium using (2-ethyl hexyl) phosphonic acid, mono (2-ethyl hexyl) ester\\/n-dodecane as an extractant system. The different extraction parameters were investigated. The distribution ratio of thorium decreased with increase in nitric acid concentration. The optimum solvent concentration for quantitative separation of thorium from

A. K. Dinkar; Suman Kumar Singh; S. C. Tripathi; R. Verma; A. V. R. Reddy

2012-01-01

435

Studies on Separation and Recovery of Thorium From Nitric Acid Medium Using (2-ethyl Hexyl) Phosphonic Acid, Mono (2-ethyl Hexyl) Ester (PC88A) \\/ N- Dodecane as Extractant System  

Microsoft Academic Search

This paper deals with the studies on the separation and recovery of thorium and 233-uranium from nitric acid medium using (2-ethyl hexyl) phosphonic acid, mono (2-ethyl hexyl) ester\\/n-dodecane as an extractant system. The different extraction parameters were investigated. The distribution ratio of thorium decreased with increase in nitric acid concentration. The optimum solvent concentration for quantitative separation of thorium from

A. K. Dinkar; Suman Kumar Singh; S. C. Tripathi; R. Verma; A. V. R. Reddy

2012-01-01

436

Quantitative determination of 2,5-piperazinediones in the products of the polycondensation of esters of ?-amino acids  

Microsoft Academic Search

Summary 1.A new method is proposed for the quantitative determination of piperazinediones in presence of peptides from the amount of dipeptides formed by alkaline hydrolysis. Titration with a copper salt and measurement of the increase in amine nitrogen give agreeing results.2.The piperazinedione contents of the polycondensation products obtained from the ethyl ester of glycine and from the ethyl ester of

K. T. Poroshin; T. D. Kozarenko; Yu. I. Khurgin

1955-01-01

437

Solid-phase extraction of galloyl- and caffeoylquinic acids from natural sources (Galphimia glauca and Arnicae flos) using pure zirconium silicate and bismuth citrate powders as sorbents inside micro spin columns.  

PubMed

Galloyl- and caffeoylquinic acids are among the most important pharmacological active groups of natural compounds. This study describes a pre-step in isolation of some selected representatives of these groups from biological samples. A selective solid-phase extraction (SPE) method for these compounds may help assign classes and isomer designations within complex mixtures. Pure zirconium silicate and bismuth citrate powders (325 mesh) were employed as two new sorbents for optimized SPE of phenolic acids. These sorbents possess electrostatic interaction sites which accounts for additional interactions for carbon acid moieties as compared to hydrophilic and hydrophobic sorbents alone. Based on this principle, a selective SPE method for 1,3,4,5-tetragalloylquinic acid (an anti-HIV and anti-asthamatic agent) as a starting compound was developed and then deployed upon other phenolic acids with success. The recoveries and selectivities of both sorbents were compared to most commonly applied and commercially available sorbents by using high performance liquid chromatography. The nature of interaction between the carrier sorbent and the acidic target molecules was investigated by studying hydrophilic (silica), hydrophobic (C18), mixed-mode (ionic and hydrophobic: Oasis(®) MAX) and predominantly electrostatic (zirconium silicate) materials. The newly developed zirconium silicate and bismuth citrate stationary phases revealed promising results for the selective extraction of galloyl- and caffeoylquinic acids from natural sources. It was observed that zirconium silicate exhibited maximum recovery and selectivity for tetragalloylquinic acid (84%), chlorogenic acid (82%) and dicaffeoylquinic acid (94%) among all the tested sorbents. PMID:23831490

Hussain, Shah; Schönbichler, Stefan A; Güzel, Yüksel; Sonderegger, Harald; Abel, Gudrun; Rainer, Matthias; Huck, Christian W; Bonn, Günther K

2013-10-01

438

Novel multifunctional acyloxyalkyl ester prodrugs of 5-aminolevulinic acid display improved anticancer activity dependent on photoactivation  

NASA Astrophysics Data System (ADS)

New approaches to PDT using multifunctional 5-aminolevulinic acid (ALA) based prodrugs activating mutual routes of toxicity are described. We investigated the mutual anti-cancer activity of ALA prodrugs which upon metabolic hydrolysis by unspecific esterases release ALA, formaldehyde or acetaldehye and the histone deacetylase inhibitor (HDACI) butyric acid. The most potent prodrug in this study was butyryloxyethyl 5-amino-4-oxopentanoate (AN-233) that stimulated a rapid biosynthesis of protoporphyrin IX (PpIX) in human glioblastoma U-251 cells and generated an efficient photodynamic destruction. AN-233 induced a considerable high level of intracellular ROS in the cells following light irradiation, reduction of mitochondrial activity, dissipation of the mitochondrial membrane potential resulting in necrotic and apoptotic cell death. The main advantage of AN-233 over ALA stems from