Showing papers on "Benzoic acid published in 2002"

Isolation and quantitative analysis of phenolic antioxidants, free sugars, and polyols from mango (Mangifera indica L.) stem bark aqueous decoction used in Cuba as a nutritional supplement.

Abstract: An aqueous decoction of mango (Mangifera indica L.) stem bark has been developed in Cuba on an industrial scale to be used as a nutritional supplement, cosmetic, and phytomedicine. Previously we reported its antioxidant activity, and we concluded that the product could be useful to prevent the production of reactive oxygen species and oxidative tissue damage in vivo. A phytochemical investigation of mango stem bark extract has led to the isolation of seven phenolic constituents: gallic acid, 3,4-dihydroxy benzoic acid, gallic acid methyl ester, gallic acid propyl ester, mangiferin, (+)-catechin, (-)-epicatechin, and benzoic acid and benzoic acid propyl ester. All structures were elucidated by ES-MS and NMR spectroscopic methods. Quantitative analysis of the compounds has been performed by HPLC, and mangiferin was found to be the predominant component. Total polyphenols were assayed also by the Folin-Ciocalteu method. The free sugars and polyols content was also determined by GC-MS.

Separation, characterization, and quantitation of benzoic and phenolic antioxidants in American cranberry fruit by GC-MS.

Abstract: A GC-MS method is reported for separation and characterization of widely different amounts of benzoic and phenolic acids as their trimethylsilyl derivatives simultaneously in cranberry. Fifteen benzoic and phenolic acids (benzoic, o-hydroxybenzoic, cinnamic, m-hydroxybenzoic, p-hydroxybenzoic, p-hydroxyphenyl acetic, phthalic, 2,3-dihydroxybenzoic, vanillic, o-hydroxycinnamic, 2,4-dihydroxybenzoic, p-coumaric, ferulic, caffeic, and sinapic acid) were identified in cranberry fruit in their free and bound forms on the basis of GC retention times and simultaneously recorded mass spectra. Except for benzoic, p-coumaric, caffeic, ferulic, and sinapic acids, 10 other phenolic acids identified have not been reported in cranberry before. The quantitation of the identified components was based on total ion current (TIC). The experimental results indicated cranberry fruit contains a high content of benzoic and phenolic acids (5.7 g/kg fresh weight) with benzoic acid being the most abundant (4.7 g/kg fresh weight). The next most abundant are p-coumaric (0.25 g/kg fresh weight) and sinapic (0.21 g/kg fresh weight) acid. Benzoic and phenolic acids occur mainly in bound forms and only about 10% occurs as free acid.

Tyrosinase inhibitors of Pulsatilla cernua root-derived materials.

Abstract: The inhibition of mushroom tyrosinase by Pulsatilla cernua root-derived materials was evaluated. The bioactive components of Pulsatilla cernua root were characterized by spectroscopic analyses as 3,4-dihydroxycinnamic acid and 4-hydroxy-3-methoxycinnamic acid, which exhibited potent antityrosinase activity. The ID50 values of 3,4-dihydroxycinnamic acid and 4-hydroxy-3-methoxycinnamic acid were 0.97 and 0.33 mM, respectively. The compounds isolated from Pulsatilla cernua roots exhibited noncompetitive inhibition against oxidation of L-DOPA by mushroom tyrosinase. This activity was compared with that of three cinnamic acid derivatives and four well-known tyrosinase inhibitors. The ID50 of 4-hydroxy-3-methoxycinnamic acid exhibited superior activity relative to anisaldehyde, anisic acid, benzoic acid, benzaldehyde, cinnamic acid, and cinnamaldehyde; but antityrosinase inhibitors and cinnamic acid derivatives, except for cinnamyl alcohol, were slightly more effective than 3,4-dihydroxycinnamic acid. In the ca...

New prenylated benzoic acid and other constituents from almond hulls (Prunus amygdalus Batsch).

Abstract: One new prenylated benzoic acid derivative, 3-prenyl-4-O-β-d-glucopyranosyloxy-4-hydroxylbenzoic acid, and three known constituents, catechin, protocatechuic acid, and ursolic acid, have been isolated from the hulls of almond (Prunus amygdalus) Complete assignments of the proton and carbon chemical shifts for the new prenylated benzoic acid derivative were accomplished on the basis of high-resolution 1D and 2D nuclear magnetic resonance data All of these compounds except ursolic acid are being reported from almond hulls (P amygdalus) for the first time Keywords: Almond hulls; Prunus amygdalus; prenylated benzoic acid derivative

Benzoic acid biosynthesis in cell cultures of Hypericum androsaemum

Abstract: Biosynthesis of benzoic acid from cinnamic acid has been studied in cell cultures of Hypericum androsaemum L. The mechanism underlying side-chain shortening is CoA-dependent and non-β-oxidative. The enzymes involved are cinnamate:CoA ligase, cinnamoyl-CoA hydratase/lyase and benzaldehyde dehydrogenase. Cinnamate:CoA ligase was separated from benzoate:CoA ligase and 4-coumarate:CoA ligase, which belong to xanthone biosynthesis and general phenylpropanoid metabolism, respectively. Cinnamoyl-CoA hydratase/lyase catalyzes hydration and cleavage of cinnamoyl-CoA to benzaldehyde and acetyl-CoA. Benzaldehyde dehydrogenase finally supplies benzoic acid. In cell cultures of H. androsaemum, benzoic acid is a precursor of xanthones, which accumulate during cell culture growth and after methyl jasmonate treatment. Both the constitutive and the induced accumulations of xanthones were preceded by increases in the activities of all benzoic acid biosynthetic enzymes. Similar changes in activity were observed for phenylalanine ammonia-lyase and the xanthone biosynthetic enzymes benzoate:CoA ligase and benzophenone synthase.

Core-functionalized star polymers by transition metal-catalyzed living radical polymerization. 2. Selective interaction with protic guests via core functionalities

Abstract: Core-functionalized star-shaped polymers consisting of linear poly(methyl methacrylate) arms and a microgel core with functional groups were found to act as efficient hosts for selective interaction with small organic molecules as guests. For example, star polymer 1 with an amide-functionalized core (Mw = 1.21 × 103; DP(arm) = 100; 71 arms/molecule; −NH−CO− in the core) could interact with benzoic acid, benzyl alcohol, and benzylamine, whereas such interaction was absent with acetophenone, ethyl benzoate, and amylbenzene, indicating that the interaction stems from hydrogen bonding between the host's amide core and the guest. Thus, polymer 1 specifically interacts with benzoic acid in an equimolar mixture of the acid and its ethyl ester. The host−guest interaction is inhibited by polar solvents such as DMF and by acids like CF3CO2H.

Measurements and modeling of the phase behavior of ternary systems of interest for the GAS process: I. The system carbon dioxide+1-propanol+salicylic acid

Abstract: As a representative model system for the gas-anti-solvent (GAS) process, the phase behavior of the ternary system carbon dioxide+1-propanol+salicylic acid has been studied experimentally. For this purpose, carbon dioxide has been chosen as the anti-solvent gas, 1-propanol as the organic solvent, and salicylic acid (2-hydroxy benzoic acid) as the model drug. In each experiment, a solution of salicylic acid in 1-propanol was expanded using carbon dioxide as the anti-solvent. A synthetic method was used for measuring bubble point curves, and the solid (salicylic acid)–liquid boundaries. Three-phase equilibrium data solid (salicylic acid)–liquid–vapor were obtained from intersection of two-phase isopleths vapor–liquid and solid–liquid. Results are reported for this ternary system at carbon dioxide concentrations ranging from 8.0 to 90.6 mol%, and within temperature and pressure ranges of 273–367 K and 1.0–12.5 MPa, respectively. It has been observed that the carbon dioxide concentration significantly affects the optimum operational conditions of the GAS process, i.e. at lower concentrations carbon dioxide acts as a co-solvent, while at higher concentrations it acts as an anti-solvent. Also, it is shown that at a proper temperature, it is possible to precipitate most of the dissolved solute with only a small change of the pressure. The Peng–Robinson equation of state as modified by Stryjek and Vera (PRSV EOS) has been used to model the ternary system.

Antifungal activity of benzoic acid derivatives from Piper lanceaefolium.

Abstract: Bioactivity-guided fractionation of a methanol extract from the leaves of Piper lanceaefolium resulted in the isolation of four new benzoic acid derivatives (1-4), together with taboganic acid, pinocembrin, and pinocembrin chalcone. Lanceaefolic acid methyl ester (3) and pinocembrin chalcone displayed activity against Candida albicans with a minimal inhibitory concentration value of 100 microg/mL in both cases.

Ruthenium Indenylidene and Vinylidene Complexes bearing Schiff Bases: Potential Catalysts in Enol-Ester Synthesis

Abstract: In an extension of our previous investigations on the ruthenium(II) Schiff-base chemistry, complexes 1, 2, 3a-b and 4a-b were synthesized and tested as catalyst for the nucleophilic addition of carboxylic acids to terminal alkynes. A careful choice of the catalytic system, substrate and carboxylic acid can provide alk- 1-en-2-yl esters, alk-1-en-1-yl esters synthesis or enyne dimerization. In this way substituted isopropenol and α-methylenebenzyl formates, (geminal, geminal) dienol diesters were synthesized in one step by direct addition of formic acid or benzoic acid to terminal mono- and di-ynes.

Model compounds and monomers for phenylene ether carboranylene ketone (PECK) polymer synthesis: preparation and characterization of boron-arylated ortho-carboranes bearing carboxyphenyl, phenoxyphenyl or benzoylphenyl substituents

Abstract: Fourteen new derivatives of ortho-carborane, 1,2-C2B10H12, have been prepared containing functionalized aryl groups attached to one or both of the boron atoms (B9 and B12) antipodal to the carbon atoms, in order to test the suitability of such species for use in the preparation of new categories of phenylene ether carboranylene ketone (PECK) polymers. Model compounds prepared from 9-iodo-ortho-carborane 1 to test synthetic procedures and reactions included the mono-substituted carboranes 9-R1-1,2-C2B10H11 in which the boron attached group R1 was p-tolyl (2), p-HO2CC6H43, p-MeOC6H4COC6H44, p-PhOC6H45 or p-PhCOC6H4OC6H46 (C6H4 represents para-phenylene throughout). Formation of 3 from 2 by CrO3 oxidation showed the capacity of the boron–aryl link to withstand strongly oxidizing conditions. Formation of 4 from 3 and anisole, PhOMe, in trifluoromethane sulfonic acid (TFSA), and of 6 from 5 and benzoic acid, PhCO2H, in TFSA showed such systems could undergo the acylation reactions that would allow polymer formation from suitable diarylcarborane monomers. Compound 7, 9-(3-PhCO-4-PhO-C6H3)-1,2-C2B10H11 an isomer of 6, was also obtained during the synthesis of 6 from 5 and benzoic acid. The diarylcarboranes 9,12-R22-1,2-C2B10H10 with R2 = p-tolyl 9, p-HO2CC6H410 or p-MeOC6H4COC6H411, bearing identical functionalised aryl groups attached to both antipodal boron atoms, were prepared from 9,12-I2-1,2-C2B10H108. Further series of diarylcarboranes 1,9- and 1,12-R32-1,2-C2B10H10, bearing identical aryl groups R3 on one carbon atom (C1) and on the antipodal boron atom (B12), or on the boron atom (B9) antipodal to the unsubstituted carbon atom (C2), have also been prepared and characterized, with R3 = p-tolyl 12, 13, p-HO2CC6H414, 15 or p-MeOC6H4COC6H416, 17.

Degradation of biphenyl by Mycobacterium sp. strain PYR-1.

Abstract: The metabolism of biphenyl by Mycobacterium sp PYR-1 was investigated The Mycobacterium sp degraded >98% of the biphenyl added within 72 h Analysis of ethyl acetate extracts of the culture medium by HPLC indicated that benzoic acid was the major metabolite Other products were 4-hydroxybiphenyl, 4-hydroxybenzoic acid, and 5-oxo-5-phenylpentanoic acid The metabolites were characterized by mass and 1H NMR spectrometry Identification of benzoic acid and 5-oxo-5-phenylpentanoic acid indicates that biphenyl degradation by Mycobacterium sp PYR-1 is generally similar to known pathways A novel alternative metabolic pathway consisted of monooxygenation at C-4 of biphenyl to give 4-hydroxybiphenyl, with subsequent degradation via ring cleavage to 4-hydroxybenzoic acid

Crystal structure of hydroxynitrile lyase from Sorghum bicolor in complex with the inhibitor benzoic acid: a novel cyanogenic enzyme.

Abstract: The crystal structure of the hydroxynitrile lyase from Sorghum bicolor (SbHNL) in complex with the inhibitor benzoic acid has been determined at 2.3 A resolution and refined to a crystallographic R-factor of 16.5%. The SbHNL sequence places the enzyme in the α/β hydrolase family where the active site nucleophile is predicted to be organized in a characteristic pentapeptide motif which is part of the active site strand−turn−helix motif. In SbHNL, however, a unique two-amino acid deletion is next to the putative active site Ser158, removing thereby the putative oxyanion hole-forming Tyr residue. The presented X-ray structure shows that the overall folding pattern of SbHNL is similar to that of the closely related wheat serine carboxypeptidase (CPD-WII); however, the deletion in SbHNL is forcing the putative active site residues away from the expected hydrolase binding site toward a small hydrophobic cleft, which also contains the inhibitor benzoic acid, defining thereby a completely different SbHNL active s...