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Cinnamic acid is a precursor of benzoic acids in cell cultures of Hypericum androsaemum L. but not in cell cultures of Centaurium erythraea RAFN.

Benzoic acids are precursors of xanthone biosynthesis which has been studied in cell cultures of Hypericum androsaemum (Hypericaceae) and Centaurium erythraea (Gentianaceae). In both cell cultures, methyl jasmonate induces the intracellular accumulation of a new xanthone. Under these inductive conditions, feeding experiments were performed with [U-14C]L-phenylalanine, [7-14C]benzoic acid and [7-14C]3-hydroxybenzoic acid. All three precursors were efficiently incorporated into the elicited xanthone in H. androsaemum, whereas 3-hydroxybenzoic acid was the only precursor to be incorporated into xanthones in C. erythraea. In addition, an appreciable increase in phenylalanine ammonia-lyase activity occurred only in methyl-jasmonate-treated cell cultures of H. androsaemum. Benzoic acids thus appear to be formed by different pathways in the two cell cultures studied. In H. androsaemum, benzoic acid is derived from cinnamic acid by side-chain degradation. In C. erythraea 3-hydroxybenzoic acid appears to originate directly from the shikimate pathway.

Acetates↗

Synthesis of 5-nitro-2-[N-3-(4-azidophenyl)-propylamino]-benzoic acid: photoaffinity labeling of human red blood cell ghosts with a 5-nitro-2-(3-phenylpropylamino)-benzoic acid analog.

A photoaffinity analog of the potent epithelial chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid has been synthesized and characterized. In the dark, this reagent, 5-nitro-2-[N-3-(4-azidophenyl)-propylamino]-benzoic acid, and the parent compound reversibly inhibited chloride efflux in human red blood cell ghosts. Irradiation of ghost membranes with 350 microM arylazide analog reduced the rate of chloride efflux to 33% of the control value. The photoinactivation process was not reversed by exhaustive washing of ghost membranes. Covalent incorporation of the photoaffinity reagent was supported by difference ultraviolet spectroscopy, which indicated the attachment of the substituted 2-amino-5-nitrobenzoic acid chromophore to ghost membranes. The novel photolabeling agent described here should be a useful structural probe for chloride channels in erythrocyte membranes and epithelial cells.

Affinity Labels↗

Variations on a theme: synthesis and modification of plant benzoic acids.

Plant benzoic acids (BAs) are critical regulators of a plant's interaction with its environment. In addition, innumerable plant-derived pharmacological agents contain benzoyl moieties. Despite the prevalence and import of plant BAs, their biosynthetic pathways are not well-defined. Mounting evidence suggests that BAs are synthesized both directly from shikimate/chorismate and from phenylalanine in plants; however, few genes in these pathways have been identified. Exciting progress has been made in elucidating genes that modify BAs via methylation, glucosylation, or activation with Coenzyme A. As these modifications alter the stability, solubility, and activity of the BAs, they impact the functional roles of these molecules. The combination of multiple BA biosynthetic routes with a variety of chemical modifications probably facilitates precise temporal and spatial control over active forms, as well as the channeling of intermediates to particular benzoate products.

Bacteria↗

[2-amino-3,5-dichloro-benzoic acid and 3-amino-2,5-dichloro-benzoic acid derivatives with phytotoxic action].

Derivatives of 2-amino-3,5-dichloro- and 3-amino-2,5-dichlorobenzoic acids have been prepared in order to extend previous research regarding the phytotoxicity of these two acids and of the corresponding N,N-di,sec.butylamides. The methyl esters of the two acids, the corresponding acids acetylated on the amino group and their respective methyl esters, and the N,N-di,sec.butylamides acetylated or formylated on the amino group were prepared. All these compounds were subjected to pre- and post-emergence tests using seven representative weeds, using doses of 6 kg/ha and, where substances proved active, at lower doses also. The results showed the importance of the N,N-di,sec.butylamide of 2-amino-3,5-dichlorobenzoic acid which, in contrast to the other derivatives tested, shows selective activity. For 3-amino-2,5-dichlorobenzoic acids and the amides tested, it was confirmed that only the acid shows marked generic phytotoxic activity in both pre- and post-emergence tests. It should be noted that the methyl ester of 3-acetylamino-2,5-dichlorobenzoic acid shows selective phytotoxicity activity.

Chlorobenzoates↗

Effect of valproic acid on glycine conjugation of benzoic acid.

Conjugation with glycine proceeds through ATP-dependent coupling of carboxylic acids with coenzyme A (CoA). Therefore, chemicals that form CoA esters may interfere with glycine conjugation. We tested the hypothesis that valproic acid (VPA), which is esterified with CoA in the first step of its mitochondrial beta-oxidation, may compromise glycine conjugation of aromatic carboxylic acids, by investigating the effect of acute VPA administration on glycine conjugation of benzoic acid in rats. VPA administered 1 hr before injection of benzoate only decreased the blood clearance of benzoate and the urinary excretion of benzoylglycine slightly in normal rats. However, in rats loaded with glycine, 2 and 3 mmol/kg of VPA reduced the blood clearance of benzoate by 34 and 59%, diminished the peak blood level of the glycine conjugate and depressed the maximal urinary excretion rate of benzoylglycine by 28 and 66%, respectively. To elucidate the mechanism of VPA-induced inhibition of benzoylglycine formation, the effects of VPA on hepatic levels of cosubstrates and the activities of enzymes involved in glycine conjugation were also determined. One hour after administration of VPA, hepatic ATP levels remained unchanged, whereas the concentration of CoA was reduced by 67 to 73% and that of glycine was increased by 58 to 67%. Activities of the enzymes of glycine conjugation were not influenced by VPA. However, 2-n-propyl-4-pentenoic acid, a metabolite of VPA, inhibited benzoyl-CoA synthetase. In summary, VPA minimally influenced the capacity of glycine conjugation of benzoic acid in normal rats, but decreased it markedly in glycine-loaded rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Thermal characterization of citric acid solid dispersions with benzoic acid and phenobarbital.

The glass transition temperatures of citric temperatures of citric acid glass were determined by differential scanning calorimetry to be 10.2 and 13.5 degrees for in situ and bulk-prepared samples, respectively. Mechanical stress on citric acid glass induced foci for crystallization. Benzoic acid addition to citric acid glass decreased its glass transition temperature while phenobarbital addition increased its glass transition temperature, the latter forming a glass solution.

Benzoates↗

[Pretreatment of benzoic acid wastewater].

The benzoic acid wastewater produced from toluene by liquid-phase oxidation is one of the difficult wastewater to treat because of multi-component, high CODcr value (20,000-100,000 mg/L) and nonbiodegradability. A pretreatment way of this wastewater by extraction based on chemical complexation was carried out, and tributyl phosphate (TBP), trialkylamine (7301) and trialkyphosphine oxide (TRPO) were used as complexing agent with n-octanol, kerosene as cosolvent and diluent respectively. Results showed that benzoic acid was recovery successfully and the CODcr value of wastewater was reduced to 1/6 of the initial value through multi-stages cross-flow extraction. Back-extraction was quite easy and the solvent could be reused.

Benzoic Acid↗

Induction of Benzoic Acid 2-Hydroxylase in Virus-Inoculated Tobacco.

Salicylic acid (SA) plays an important role in the induction of plant resistance to pathogens. An accompanying article (N. Yalpani, J. Leon, M.A. Lawton, I. Raskin [1993] Plant Physiol 103: 315-321) shows that SA is synthesized via the decarboxylation of cinnamic acid to benzoic acid (BA), which is, in turn, hydroxylated to SA. Leaf extracts of tobacco (Nicotiana tabacum L. cv Xanthi-nc) catalyze the 2-hydroxylation of BA to SA. The monooxygenase catalyzing this reaction, benzoic acid 2-hydroxylase (BA2H), required NAD(P)H or reduced methyl viologen as an electron donor. BA2H activity was detected in healthy tobacco leaf extracts (1-2 nmol h-1 g-1 fresh weight) and was significantly increased upon inoculation with tobacco mosaic virus (TMV). This increase paralleled the levels of free SA in the leaves. Induction of BA2H activity was restricted to tissue expressing a hypersensitive response at 24[deg]C. TMV induction of BA2H activity and SA accumulation were inhibited when inoculated tobacco plants were incubated at 32[deg]C. However, when inoculated plants were incubated for 4 d at 32[deg]C and then transferred to 24[deg]C, they showed a 15-fold increase in BA2H activity and a 65-fold increase in free SA content compared with healthy plants incubated at 24[deg]C. Treatment of leaf tissue with the protein synthesis inhibitor cycloheximide blocked the induction of BA2H activity by TMV. The effect of TMV inoculation on BA2H could be duplicated by infiltrating leaf discs of healthy plants with BA. This response was observed even when applied levels of BA were much lower than the levels observed in vivo after virus inoculation. Feeding tobacco leaves with phenylalanine, cinnamic acid, or o-coumaric acid (putative precursors of SA) failed to trigger the induction of BA2H activity. BA2H appears to be a pathogen-inducible protein with an important regulatory role in SA accumulation during the development of induced resistance to TMV in tobacco.

Journal Article↗

[Pretreatment and resource utilization of industrial effluent with benzoic acid].

Extraction equilibrium of benzoic acid were studied using 20%, 30% and 50% tributyl phosphate (TBP) in kerosene, 1-octanol and toluene as the extractants, to investigate the efficient method of recovering benzoic and acetic acid in the industrial effluent and meeting the requirement of the terminal wastewater treatment. The CODCr value in residual phase and the recovery of benzoic acid in various extractants were measured. The results showed that the recovery of benzoic acid was closed to 100% with 50% TBP/kerosene system, and depended on the polarity of extractant for pure solvent system. The recovery with 1-octanol was equivalent to the one with 30% TBP. The CODCr value in the residual phase depended on the CODCr value from benzoic acid and the solubility of extractant, which does not depend on the benzoic acid concentration in the residue phase apparently, and shown 50% TBP approximately equal to 30% TBP > 1-octanol > 20% TBP > toluene. Meanwhile, the profitable diagram of pretreatment of industrial effluent with benzoic acid was suggested, i.e. firstly, extract benzoic acid with toluene and return the toluene to the benzoic acid reactor, then, extract acetic acid with trialkylphosphine oxide and back-extract the acetic acid with CaO or MgO to produce calcium magnesium acetate.

1-Octanol↗

Effect of chlorophenoxyacetic acid herbicides on glycine conjugation of benzoic acid.

1. 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) (0.1-0.5 mmol/kg i.p.) delayed the disappearance of injected benzoate from blood and diminished the urinary excretion of the formed benzoylglycine, but elevated the blood levels of benzoylglycine in rat, suggesting that these herbicides interfere with both the formation and the renal transport of benzoylglycine. 2. Inhibition of the renal excretion of benzoylglycine by 2,4-D or 2,4,5-T (0.5 mmol/kg i.p.) was directly demonstrated in rat injected with benzoylglycine. 3. Inhibition of benzoylglycine formation from benzoic acid by 2,4-D or 2,4,5-T (0.5 mmol/kg i.p.) was directly demonstrated in renal pedicles-ligated rats injected with benzoate. 4. Neither 2,4-D nor 2,4,5-T influenced the hepatic concentrations of ATP, coenzyme A (CoA) or glycine; therefore, it is unlikely that they inhibit glycine conjugation of benzoic acid by diminishing the availability of co-substrates. 5. Although the chlorophenoxyacetic acids did not appear to be a substrate for the mitochondrial acyl-CoA synthetases, both 2,4-D and 2,4,5-T diminished the activity of benzoyl-CoA synthetase (but not that of benzoyl-CoA:glycine N-acyltransferase) in solubilized hepatic mitochondria. These findings suggest that 2,4-D and 2,4,5-T impair benzoylglycine formation in rat by inhibiting benzoyl-CoA synthetase.

2,4,5-Trichlorophenoxyacetic Acid↗

Chemical structure and biodegradability of halogenate aromatic compounds. Substituent effects on 1,2-dioxygenation of benzoic acid.

Dioxygenation of substituted benzoic acids by whole cells of 3-chlorobenzoate-utilizing Pseudomonas sp. B 13, benzoate-induced cells of Alcaligenes eutrophus B 9 and toluate-grown cells of Pseudomonas putida mt-2 was examined. Electron-attracting substituents like halogen decreased the reaction rates of benzoate 1,2-dioxygenation. Dioxygenation of substituted benzoic acids by P. putida mt-2 was mostly undisturbed by steric effects of the substituents. Good correlation resulted between the log Vrel values and the Hammett substituent constant sigma. In contrast the reaction rates of dioxygenation by Pseudomonas sp. B 13 and A. eutrophus were decreased predominantly by steric effects of substituents. A non-polar reaction mechanism of benzoate 1,2-dioxygenation is discussed. Results from inhibition studies demonstrate high stereospecificities for the 1,2-dioxygenation by Pseudomonas sp. B 13 of benzoic acids with substituents in ortho- or para-position. In the case of P. putida mt-2 steric handrance by substituents was observed only with orth-substituted benzoic acids. Stereospecificities of the benzoate 1,2-dioxygenation by Pseudomonas sp. B 13 and P. putida mt-2 are illustrated schematically.

Bacteria↗

Acidity of ortho-substituted benzoic acids: an infrared and theoretical study of the intramolecular hydrogen bonds.

The structures of ortho-substituted benzoic acids with substituents bearing hydrogen atoms (OH, NH2, COOH and SO2NH2) were investigated by means of IR spectroscopy and of density functional theory at the B3LYP/6-311 + G(d,p) level. All possible conformations, hydrogen bonds, tautomeric forms and zwitterions were taken into consideration and particular attention was given to intramolecular H-bonds and their effect on acidity. Strong H-bonds in the anions of all four acids, were revealed by calculations. In three cases they were confirmed by the IR spectra of the tetrabutylammonium salts in tetrachloromethane solution, while the salt of 1,2-benzenedicarboxylic acid was not sufficiently soluble. The H-bonds are of different strengths but in all cases they are the main cause of the strengthened acidity of these acids in the gas phase and also in solution, although their effect is opposed by weaker H-bonds present in the undissociated acid molecules. The substituent effect on the acidity was evaluated in terms of isodesmic reactions, separately in the acid molecules and in the anions. While the acidity of the 2-OH and 2-NH2 acids is determined essentially by the H-bonds, that of the 2-COOH and 2-SO2NH2 acids is strengthened by the polar effect operating in the undissociated molecule in addition to the H-bond in the anion. The steric inhibition of resonance (SIR), estimated from model conformations with fixed torsional angles, is of little importance. This analysis goes significantly beyond the classical explanation obtained from the acidities in solution but essentially conforms with it.

Journal Article↗

Proteins induced in Escherichia coli by benzoic acid.

Proteins induced by benzoic acid in Escherichia coli were observed on two-dimensional electrophoretic gels (2-D gels). Cultures were grown in glucose-rich medium in the presence or absence of 20 mM benzoate at an external pH of 6.5, where the pH gradient (deltapH) is large and benzoate accumulates, and at an external pH of 8.0, where deltapH is inverted and little benzoate is taken up. Radiolabeled proteins were separated on 2-D gels and were identified on the basis of the index of VanBogelen and Neidhardt. In the absence of benzoic acid, little difference was seen between pH 6.5 and pH 8.0; this confirms that the mechanisms of protein homeostasis in this range are constitutive, including the transition between positive and inverted deltapH. Addition of benzoate at pH 6.5 increased the expression of 33 proteins. Twelve of the benzoate-induced proteins were induced at pH 8.0 as well, and nine of these matched proteins induced by the uncoupler dinitrophenol. Eighteen proteins were induced by benzoate only at pH 6.5, not at pH 8.0, and were not induced by dinitrophenol. One may be the iron and pH regulator Fur, which regulates acid tolerance in Salmonella spp. The other 13 proteins had not been identified previously. The proteins induced by benzoate only at a low pH may reflect responses to internal acidification or to accumulation of benzoate.

Bacterial Proteins↗

In vivo and in vitro renal metabolism and excretion of benzoic acid by a marine teleost, the southern flounder.

In mammals, benzoic acid is primarily metabolized to its glycine conjugate, hippuric acid, which is readily excreted via the renal organic anion transport system. Teleost fish have not been shown to make glycine conjugates of carboxylic acids. Therefore, metabolism, excretion, and renal transport of benzoic acid were examined in the southern flounder, Paralichthys lethostigma. Excretion of injected [14C]benzoic acid was slow (10% of the administrated dose/day) and followed zero order kinetics. More than 95% of the excreted label was a single metabolite which was shown by hydrolysis and TLC to be benzoyltaurine. Isolated renal tubules and both hepatic and renal mitochondria produced benzoyltaurine in vitro. Excretion of benzoic acid and benzoyltaurine were not limited by plasma binding (less than 5% bound). To examine whether the slow excretion reflected renal transport, the transport of 100 microM benzoic acid, benzoyltaurine, and hippuric acid were determined in isolated renal tubules. All three compounds were accumulated via a probenecid- and cyanide-sensitive mechanism. Probenecid-sensitive uptake at 60 min of hippuric acid (436 nmol/mg) was greater than that of benzoyltaurine (164 nmol/mg) and both exceeded uptake of benzoic acid (63 nmol/mg). The same pattern was seen at 10 microM, except that tissue:medium ratios were even greater, indicating at least partial saturation of transport at 100 microM. Thus, the slow excretion of benzoic acid by these flounder was due to a combination of factors, including slow metabolism of benzoic acid to benzoyltaurine, saturation of the transport of benzoyltaurine, and low affinity of secretory transport for benzoic acid and benzoyltaurine, relative to hippuric acid, the mammalian metabolite.

Animals↗