PURPOSE: The purpose of this study was to determine the protective effect of alpha-lipoic acid against oxidative damage in rabbit conjunctiva and cornea exposed to ultraviolet radiation. METHODS: 20 rabbits weighing 2,500- 3,000 g were used, and we divided them into 4 groups with 5 randomly selected rabbits. The rabbits ...

We have examined the effects of midazolam, Ro 5-4864 (agonist for "peripheral" [p] benzodiazepine receptors [BR]), PK 11195 (antagonist for pBR), flumazenil (antagonist for "central" BR), naloxone (antagonist for opiate receptors) and the combination of midazolam and Ro 5-4864, PK 11195, flumazenil or naloxone on intracellular amino- and alpha-keto acids ...

A simple method for preparation of fluoroalkyl beta-enaminophosphonates 1 from alkylphosphonates 2 and perfluoroalkyl nitriles 3 is reported. Olefination reaction of functionalized phosphates 1 with aldehydes gives alpha,beta-unsaturated imines 5. Acid hydrolysis of these fluoroalkyl derivatives 5 affords alpha,beta-unsaturated ketones 6, while their selective reduction with hydrides leads to the ...

Obesity shortens life expectancy and is a risk factor for hypertension and Type 2 diabetes. When added to the standard chow of Sprague-Dawley or Otsuka Long-Evans Tokushima Fatty rats, alpha-lipoic acid (0.5% weight/weight) reduced body weight and food intake. Alpha-lipoic acid also increased whole-body energy expenditure. It exerts its effects ...

Non-alpha-tocopherols are hydroxymethylated and hydrogenated to produce alpha-tocopherol in one pot process by simultaneously reacting with paraformaldehyde and hydrogen in the presence of catalysts of benzenesulfonic acid and 5% Pd/C in an autoclave. Effects of various operation conditions have been studied. The preferable reaction conditions are: temperature 180 degrees C ...

The physiological effects of 9cis,11trans,13cis-conjugated linolenic acid (9c,11t,13c-CLNA), one of the CLNA isomers, were studied in human hepatoma HepG2 cells. 9c,11t,13c-CLNA significantly decreased apolipoprotein B100 secretion compared with alpha-linolenic acid (alpha-LNA). The uptake of (14)C-oleate into newly synthesized cellular triacylglycerol was also decreased by 9c,11t,13c-CLNA more than by alpha-LNA treatment. ...

A series of zwitterionic lambda(5)Si-silicates with a (2,2,6,6-tetramethylpiperidinio)methyl group and two identical bidentate ligands derived from glycine, (S)-alanine, (S)-phenylalanine, glycolic acid, (S)-lactic acid, (S)-3-phenyllactic acid, or (S)-mandelic acid were synthesized and structurally characterized (solution and solid-state NMR spectroscopy; single-crystal X-ray diffraction). The chiral lambda(5)Si-silicates with ligands derived from optically active ...

We examined the mechanisms underlying the activation of group IVA cytosolic phospholipase A(2) (cPLA(2)alpha) contributing to the supply of fatty acids required for the formation of cholesteryl ester in oxidized low-density lipoprotein (oxLDL)-stimulated macrophages. The possible involvement of oxidized lipids was also examined. In [(3)H]arachidonic acid-labeled mouse peritoneal macrophages, oxLDL ...

The objective of this study was to determine the effects of ornithine on polymorphonuclear leucocyte (PMN) free amino- and alpha-keto acid profiles, superoxide anion (O2-) generation, hydrogen peroxide (H2O2) formation and released myeloperoxidase activity (MPO). Exogenous ornithine significantly increased PMN asparagine, glutamine, aspartate, glutamate, arginine, citrulline, alanine, alpha-ketoglutarate and pyruvate ...

o-Phthalaldehyde in combination with chiral thiols is described as a chiral reagent for the resolution of the enantiomers of alpha-H-alpha-aminonitriles and alpha-alkyl-alpha-aminonitriles. Separation of the resulting diastereomers was carried out by reversed-phase chromatography and the derivatives were detected at UV 340 nm. The identity of the diastereomeric derivatives was confirmed ...

OBJECTIVE: We have examined the effect of alpha-lipoic acid (ALA, tioctic acid; Tiobec), a free radical scavenger, on the discomfort of burning mouth syndrome (BMS) in patients who had used tranquillizers previously, compared with those who had not. METHODS: In this study we gave lipoic acid for 2 months to ...

Low concentrations of branched-chain fatty acids, such as isobutyric and isovaleric acids, develop during the ripening of hard cheeses and contribute to the beneficial flavor profile. Catabolism of amino acids, such as branched-chain amino acids, by bacteria via aminotransferase reactions and alpha-keto acids is one mechanism to generate these flavorful ...

Dissolution enthalpies of L-alpha-aminobutyric acid, L-alpha-isoleucine, L-alpha-phenylalanine, L-alpha-methionine, L-alpha-serine, L-alpha-threonine, L-alpha-cysteine, L-alpha-asparagine and L-alpha-glutamine in aqueous solutions of urea have been measured by calorimetry at 298.15 K. The obtained results were used to calculate the enthalpic interaction coefficients between the zwitterions of the L-alpha-amino acids and a molecule of urea ...

Lipoic acid was found to inhibit the firefly luciferin-luciferase reaction. The inhibition is competitive and is the strongest known (Ki = 0.026 +/- 0.013 microM) compared with other reported inhibitors. Considering the structure-activity correlations, the mechanism of inhibition may originate from the sulfur atom and carboxyl moiety of lipoic acid ...

[reaction: see text] We report a new enantioselective synthesis of (-)-alpha-kainic acid from d-serine methyl ester hydrochloride, based on a (-)-sparteine-mediated asymmetric deprotonation of an intermediate carbamate that, by stereospecific anti S(N)'S(E)' intramolecular cycloalkylation, leads to the pyrrolidine ring precursor of (-)-alpha-kainic acid, in high yield and diastereoselectivity. The intermediate ...

A practical, one-pot process for the preparation of beta-keto amides via a three-component reaction, including Meldrum's acid, an amine, and a carboxylic acid, has been developed. Key to development of an efficient, high-yielding process was an in-depth understanding of the mechanism of the multistep process. Kinetic studies were carried out ...

The four pyruvate dehydrogenase kinase (PDK) and two pyruvate dehydrogenase phosphatase (PDP) isoenzymes that are present in mammalian tissues regulate activity of the pyruvate dehydrogenase complex (PDC) by phosphorylation/dephosphorylation of its pyruvate dehydrogenase (E1) component. The effect of lipoic acids on the activity of PDKs and PDPs was investigated in ...

Metabolism of aromatic amino acids by lactic acid bacteria is an important source of off-flavor compounds in Cheddar cheese. Previous work has shown that alpha-keto acids produced from Trp, Tyr, and Phe by aminotransferase enzymes are chemically labile and may degrade spontaneously into a variety of off-flavor compounds. However, dairy ...

The gas-phase acidity of D-glucopyranose was studied by means of B3LYP calculations combined with 6-31G(d,p) or 6-31+G(d,p) standard basis sets. For each anomer, deprotonation of the various primary and secondary hydroxyl groups was considered. As in solution, the anomeric hydroxyl is found to be the most acidic for both anomers, ...

External addition of the beta-lactam precursor alpha-aminoadipic acid to the filamentous fungus Penicillium chrysogenum leads to an increased intracellular alpha-aminoadipic acid concentration and an increase in penicillin production. The exact route for alpha-aminoadipic acid uptake is not known, although the general amino acid and acidic amino acid permeases have been ...

13C-NMR has been used to follow the tryptophan synthase (EC 4.2.1.20) catalysed hydrogen-deuterium exchange of the pro-2R and pro-2S protons of [2-13C]glycine at pH 7.8. 1H-NMR has also been used to follow the tryptophan-synthase-catalysed hydrogen-deuterium exchange of the alpha-protons of a range of L- and D-amino acids at pH 7.8. ...

Lipoic acid is an essential cofactor of alpha-keto acid dehydrogenase complexes (KADHCs). This study shows that Plasmodium falciparum possesses two distinct lipoylation pathways that are found in separate subcellular localizations. Lipoic acid synthesis comprising lipoic acid synthase and lipoyl-ACP:protein N-lipoyl transferase is present in the parasite's apicoplast, whereas the second ...

Although a large number of key odorants of Swiss-type cheese result from amino acid catabolism, the amino acid catabolic pathways in the bacteria present in these cheeses are not well known. In this study, we compared the in vitro abilities of Lactobacillus delbrueckii subsp. lactis, Lactobacillus helveticus, and Streptococcus thermophilus ...

Detailed investigation on the origin of the acidity of the alpha-protons of a set of the carbonyl molecules was carried out on the basis of properties of the localized molecular orbital. An anomalously high acidity of Meldrum's acid, as compared with those of dimedone and dimethyl malonate, is one of ...

BACKGROUND: We studied the effect on skin papillomas of topical application of a complex of alpha-lactalbumin and oleic acid (often referred to as human alpha-lactalbumin made lethal to tumor cells [HAMLET]) to establish proof of the principle that alpha-lactalbumin-oleic acid kills transformed cells but not healthy, differentiated cells. METHODS: Forty ...

O-Protected 3-hydroxyoxazolidin-2,4-diones have been prepared in a novel one-pot reaction by subsequent treatment of cyanohydrins with 1,1'-carbonyldiimidazole and O-protected hydroxylamines followed by acidic hydrolysis of the intermediate 4-imino-oxazolidin-2-ones. Decarbonylation of O-protected 3-hydroxyoxazolidin-2,4-diones by catalytic amounts of sodium methoxide, lithium hydroxide, sodium carbonate and caesium carbonate in methanol afforded O-protected alpha-hydroxyhydroxamic ...

trans-Cinnamic acid and its derivatives were investigated for the alpha-glucosidase inhibitory activity. 4-Methoxy-trans-cinnamic acid and 4-methoxy-trans-cinnamic acid ethyl ester showed the highest potent inhibitory activity among those of trans-cinnamic acid derivatives. The presence of substituents at 4-position in trans-cinnamic acid altered the alpha-glucosidase inhibitory activity. Increasing of bulkiness and the ...

A chelating resin was synthesized by incorporating thiosemicarbazide into Amberlite IRC-50, a weakly acidic polymer. Astatine radionuclides produced by alpha-irradiating bismuth oxide were separated using the newly synthesized chelating resin. The resin showed high selectivity for astatine. The adsorbed astatine was recovered using 0.1M EDTA at pH approximately 10.

A stereoselective synthesis of functionalised (2R,3R)-2,3-dimethyl-3-amidotetrahydrofuran-4-one, its (2S,3R)-epimer and (3aR,6aR)-N-(3-oxo-hexahydrocyclopenta[b]furan-3a-yl)acylamide cysteinyl proteinase inhibitors has been developed using Fmoc-protected scaffolds 6-8 in a solid-phase combinatorial strategy. Within these scaffolds, the introduction of an alkyl substituent alpha to the ketone affords chiral stability to an otherwise configurationally labile molecule. Preparation of scaffolds ...

Camphene is an industrial intermediate compound for commercial chemicals such as isoborneol, isobornyl acetate and camphor. Industrially, the conventional process for camphene production consists of the isomerization of alpha-pinene using acidic TiO2 as catalyst. The use of this catalyst presents problems such as considerable time for preparation, reproducibility and recovery ...

Five-, six-, and seven-membered cyclic alpha-amino phosphonates, amino acid surrogates, are prepared in enantiomerically pure form via the highly diastereomeric addition of metal phosphonates to masked oxo sulfinimines. Hydrolysis of the resulting masked oxo alpha-amino phosphonates followed by reduction of the intermediate cyclic imino phosphonates affords the title compounds in ...

Protected alpha-formyl amino acids, themselves available from the corresponding alpha-vinyl amino acids, are stereoselectively transformed into the (Z)-configured alpha-(2'-fluoro)vinyl amino acids via a three-step sequence. The route employs McCarthy's reagent, diethyl alpha-fluoro-alpha-(phenylsulfonyl)methyl phosphonate, and proceeds via the intermediate (E)-alpha-fluorovinyl sulfones and (E)-alpha-fluorovinylstannanes. The latter may either be exploited as novel ...

The interferon-alpha genes from three chicken lines were cloned by a direct PCR technique, and the effects of recombinant protein expressed in a prokaryotic system on highly pathogenic H9N2 influenza viruses were investigated. The cloned ChIFN-alpha gene encoded a protein of 193 amino acids with a signal sequence of 31 ...

Alpha-hydroxy acids have been used for rejuvenation since ancient times, and now there are several on the market. Depending on the concentration, some have been shown to be effective as peeling agents and for rejuvenation. Glycolic acid and lactic acid are the alpha-hydroxy acids most frequently used in cosmetics, although ...

alpha-Amino acids are important building blocks for the synthesis of a large number of bioactive compounds and pharmaceutical drugs. However, a literature survey revealed that no theoretical conformational study of alpha-amino acids with cage carbon frameworks has been performed to date. This paper reports the results of a conformational study ...

A general two-step preparation of enantiopure N(alpha),N(beta)-orthogonally diprotected alpha-hydrazino acids 1 is developed on a multigram scale. The key reaction is the efficient electrophilic amination of N-benzyl amino acids 6 with N-Boc-oxaziridine 7 and accommodates various functional groups encountered in side chains of amino acids. The cyclic 2,3,4,5-tetrahydro-3-pyridazine carboxylic acid ...

PURPOSE: Several studies have examined the association between polyunsaturated fatty acids and prostate cancer risk. We evaluated the evidence on the association between the essential polyunsaturated fatty acid, known as alpha-linolenic acid, and the risk of prostate cancer in humans. MATERIALS AND METHODS: We comprehensively reviewed published studies on the ...

Formation of flavor compounds from branched-chain alpha-keto acids in fermented foods such as cheese is believed to be mainly an enzymatic process, while the conversion of phenyl pyruvic acid, which is derived from phenylalanine, also proceeds chemically. In this research, the chemical conversion of alpha-keto acids to aldehydes with strong ...

PURPOSE OF REVIEW: This review critically evaluates current knowledge of alpha-linolenic acid metabolism in adult humans based on the findings of studies using stable isotope tracers and on increased dietary alpha-linolenic acid intake. The relative roles of alpha-linolenic acid and of longer-chain polyunsaturated fatty acids in cell structure and function ...

Herein we report an efficient procedure to synthesize S-4-(3-thienyl)phenyl-alpha-methylacetic acid, an enantiomerically pure intermediate of a recently approved nonsteroidal antiinflammatory cyclooxygenase inhibitor, atliprofen [methyl RS-4-(3-thienyl)phenyl-alpha-methylacetate]. The interactions of the active S-isomer of the acid were theoretically compared with those of S-ibuprofen through molecular docking studies using COX-1 and COX-2 protein ...

Modifications of the alkyl acetic acid portion and the phenyl on pyrrolidine in our lead pyrazole compound 1 afforded the isopropyl compound 9. This compound is a potent CCR5 antagonist showing good in vitro antiviral activity against HIV-1, an excellent selectivity profile, and good oral bioavailability in three animal species. ...

A practical synthesis for the preparation of a diverse series of cyclopropane alpha-amino acids is described. Nitrocyclopropane carboxylates can be readily prepared through treatment of alpha-nitroesters and iodobenzene diacetate or alpha-nitro-alpha-diazoesters with a Rh(II) catalyst and an olefin. Reduction of the nitro group using zinc/HCl in i-PrOH affords substituted cyclopropane ...

[reaction: see text] The preparation of depsi-peptides, amide-to-ester-substituted peptides used to probe the role of hydrogen bonding in protein folding energetics, is accomplished by replacing specific l-alpha-amino acid residues by their alpha-hydroxy acid counterparts in a solid-phase synthesis employing a t-Boc strategy. Herein we describe the efficient stereoselective synthesis of ...

[reaction: see text] Beta-substituted alpha,beta-unsaturated alpha-nitro esters and amides undergo radical conjugate additions when treated with an appropriate Lewis acid. Deuterium studies revealed that the acidic alpha-stereocenter of the alpha-nitro ester products does not racemize under strictly controlled workup conditions. The alpha-nitro amides did racemize significantly during chromatography, but this ...

The novel Calpha-tetrasubstituted alpha-amino acid Calpha-methyl, Calpha-cyclohexylglycine was prepared by hydrogenation of its Calpha-methyl, Calpha-phenylglycine precursor. Terminally protected homodi-, homotri-, and homotetrapeptides from Calpha-methyl, Calpha-cyclohexylglycine and co-oligopeptides to the pentamer level in combination with Gly or alpha-aminoisobutyric acid residues were prepared by solution methods and fully characterized. The results of ...

Lipoic acid-dependent pathways of alpha-keto acid oxidation by mitochondria were investigated in pea (Pisum sativum), rice (Oryza sativa), and Arabidopsis. Proteins containing covalently bound lipoic acid were identified on isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis separations of mitochondrial proteins by the use of antibodies raised to this cofactor. All these ...

The CHCl(3) extract of the bark of Garcinia speciosa contained four 17,14-friedolanostanes and five lanostanes as well as friedelin and common plant constituents. The friedolanostanes were the previously known methyl ester of (24E)-3 alpha,23 alpha-dihydroxy-17,14-friedolanostan-8,14,24-trien-26-oic acid and the methyl esters of three hitherto unknown acids, 3 alpha-hydroxy-16 alpha,23 alpha-epoxy-17,14-friedolanostan-8,14,24-trien-26-oic acid, ...

Alpha-oxoglutaric acid was attached to trypsin via reductive alkylation with NaBH4 thereby introducing metal-chelating groups at the protein surface. The thermostability of the modified enzyme was increased by 6.5-13 degrees C and its resistance to autolytic degradation was improved 2- to 4-fold in 5 mM ZnCl2, MnCl2 or MgCl2.

Stir bar sorptive extraction-liquid desorption (SBSE-LD) has been applied as an efficient sample preparation method for the analysis of beer bitter acids. Extracts free of almost all interfering compounds were obtained, allowing simultaneous analysis of iso-alpha-acids and reduced iso-alpha-acids. A robust micellar electrokinetic chromatography (MEKC) method was developed that enables ...

[reaction: see text] An efficient and cost-effective synthesis of N(alpha)-Boc2-N(beta)-Cbz-2,3-diaminopropionic acid is reported. The synthesis starts from commercially available N(alpha)-Boc-Asp(OBn)-OH and employs a Curtius rearrangement to establish the beta-nitrogen. Proper protection of the alpha-nitrogen is essential for the success of the Curtius rearrangement.