PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “SHIKIMIC ACID”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed2001

Algal growth inhibition effects and inducement modes by plant-producing phenols.

Evaluated here are the inhibitory effects on blue-green algae (Microcystis aeruginosa) produced by nine plant-producing phenols (caffeic, p-coumaric, ferulic, protocatechuic, sinapic, syringic, and vanillic acids, catechol, and hydroquinone), two plant-produced acids (quinic and shikimic acid), phenol, resorcinol, hydroxy hydroquinone, and phloroglucinol. Algal assays confirmed growth inhibition of M. aeruginosa by polyphenols, i.e., caffeic/protocatechuic acid, catechol, hydroquinone, hydroxy hydroquinone, and phloroglucinol, and by phenols containing methoxy groups, i.e., vanillic, sinapic, and syringic acids. Accordingly, this indicates good feasibility for controlling growth of M. aeruginosa using such plant-producing polyphenols and/or phenols as additives. A comparison of the inhibitory effects of the polyphenols showed that those induced by polyphenols in which phenolic hydroxy groups bound a benzene ring at ortho- and/or para-positions to another phenolic hydroxy group are stronger than the effects induced by polyphenols in which phenolic hydroxy groups are at only meta-positions. Experiments showed that the only polyphenols demonstrating significant growth inhibition of M. aeruginosa were autoxidized. These results suggest that autoxidation of the polyphenols induces inhibitory effects by producing polyphenol-autoxidized products such as radicals.

Eukaryota↗
PubMed2001

Glyphosate inhibits melanization of Cryptococcus neoformans and prolongs survival of mice after systemic infection.

Cryptococcus neoformans is a major fungal pathogen and is a relatively common cause of life-threatening meningoencephalitis. Glyphosate is a widely used herbicide that inhibits the synthesis of aromatic amino acids via the shikimate acid pathway. This study investigated the effects of glyphosate on C. neoformans growth, melanization, and murine infection. C. neoformans was relatively resistant to glyphosate, requiring concentrations >250 microg/mL for inhibition. Melanization of C. neoformans in the presence of L-dopa was inhibited by subinhibitory concentrations of glyphosate. Glyphosate inhibited autopolymerization of L-dopa and oxidation of L-epinephrine by cryptococcal cells, which is mediated by a laccase. Administration of glyphosate to mice infected with C. neoformans delayed melanization of yeast cells in vivo and prolonged average mouse survival. The results suggest that inhibition of melanization in vivo may facilitate control of C. neoformans infection.

Animals↗
PubMed2002

Acylated and non-acylated flavonol monoglycosides from the Indian minor spice Nagkesar (Mammea longifolia).

A methanol extract of nagkesar (buds of Mammea longifolia), which showed strong radical scavenging activity, yielded 13 compounds by separations using column chromatography and HPLC. Structure elucidation of these compounds was achieved by (1)H and (13)C NMR, including DQF-COSY, TOCSY, DEPT, HMQC, HSQC, and HMBC. They include two new compounds, quercetin 3-O-(2' ',4' 'di-E-p-coumaroyl)-alpha-L-rhamno-pyranoside and quercetin 3-O-(3' ',4' '-di-E-p-coumaroyl)-alpha-L-rhamnopyranoside, along with known compounds kaempferol, quercetin, the isopropylidenedioxy derivative of shikimic acid, kaempferol 3-O-(2' ',4' '-di-E-p-coumaroyl)-alpha-L-rhamnopyranoside, kaempferol 3-O-(3' ',4' '-di-E-p-coumaroyl)-alpha-L-rhamnopyranoside, kaempferol 3-O-alpha-L-rhamnopyranoside, quercetin 3-O-alpha-L-rhamnopyranoside, shikimic acid, kaempferol 3-O-beta-D-glucopyranoside, quercetin 3-O-beta-D-glucopyranoside, and beta-sitosterol 3-O-beta-D-glucopyranoside.

Acylation↗
PubMed2006

Synthesis of trimethyl (2S,3R)- and (2R,3R)-[2-2H1]-homocitrates and dimethyl (2S,3R)- and (2R,3R)-[2-2H1]-homocitrate lactones-an assay for the stereochemical outcome of the reaction catalysed both by homocitrate synthase and by the Nif-V protein.

Trimethyl (3R)-homocitrate 17, trimethyl (2S,3R)-[2-2H1]-homocitrate 17a and (2R,3R)-[2-2H1]-homocitrate 17b, as well as dimethyl (3R)-homocitrate lactone 18, (2S,3R)-[2-2H1]-homocitric lactone 18a and (2R,3R)-[2-2H1]-homocitric lactone 18b have been synthesised. D-quinic acid 12 was used as the source of the (3R)-centre in the unlabelled target compounds 17 and 18. (2)-Shikimic acid 19 and the (2)-[2-2H]-shikimic acid derivative 32 respectively were used in the synthesis of the labelled compounds. In the latter syntheses, Sharpless directed epoxidation of the olefin in the 5-deoxy ester diols 23 and 35 ensured a reaction from the same face as the allylic and homoallylic alcohols, and the reduction of the protected epoxides 25 and 37 ensured that the label was introduced in a stereoselective manner. The 1H NMR spectra of the labelled products present an assay for the stereochemistry of the biological reactions catalysed by homocitrate synthase and by the protein from the nifV gene.

Bacterial Proteins↗
PubMed2002

Thermodynamics of reactions catalyzed by PABA synthase.

Microcalorimetry and high-performance liquid chromatography (HPLC) have been used to conduct a thermodynamic investigation of reactions catalyzed by PABA synthase, the enzyme located at the first step in the shikimic acid metabolic pathway leading from chorismate to 4-aminobenzoate (PABA). The overall biochemical reaction catalyzed by the PabB and PabC components of PABA synthase is: chorismate(aq)+ammonia(aq)=4-aminobenzoate(aq)+pyruvate(aq)+H(2)O(l). This reaction can be divided into two partial reactions involving the intermediate 4-amino-4-deoxychorismate (ADC): chorismate(aq)+ammonia(aq)=ADC(aq)+H(2)O(l) and ADC(aq)=4-aminobenzoate(aq)+pyruvate(aq). Microcalorimetric measurements were performed on all three of these reactions at a temperature of 298.15 K and pH values in the range 8.72-8.77. Equilibrium measurements were performed on the first partial (ADC synthase) reaction at T=298.15 K and at pH=8.78. The saturation molality of 4-aminobenzoate(cr) in water is (0.00382+/-0.0004) mol kg(-1) at T=298.15 K. The results of the equilibrium and calorimetric measurements were analyzed in terms of a chemical equilibrium model that accounts for the multiplicity of ionic states of the reactants and products. These calculations gave thermodynamic quantities at the temperature 298.15 K and an ionic strength of zero for chemical reference reactions involving specific ionic forms. For the reaction: chorismate(2-)(aq)+NH(4)(+)(aq)=ADC(-)(aq)+H(2)O(l), K=(10.8+/-4.2) and Delta(r)H(m)(o)=-(35+/-15) kJ mol(-1). For the reaction: ADC(-)(aq)=4-aminobenzoate(-)(aq)+pyruvate(-)(aq)+H(+)(aq), Delta(r)H(m)(o)=-(139+/-23) kJ mol(-1). For the reaction: chorismate(2-)(aq)+NH(4)(+)(aq)=4-aminobenzoate(-)(aq)+pyruvate(-)(aq)+H(2)O(l)+H(+)(aq), Delta(r)H(m)(o)=-(174+/-6) kJ mol(-1). Thermodynamic cycle calculations were used to calculate thermodynamic quantities for three additional reactions that utilize L-glutamine rather than ammonia and that are pertinent to this branch point of the shikimic acid pathway. The quantities obtained in this study permit the calculation of the position of equilibrium of these reactions as a function of temperature, pH, and ionic strength. Values of the apparent equilibrium constants and the standard transformed Gibbs energy changes Delta(r)G'(m)(o) under approximately physiological conditions are given.

Calorimetry↗
PubMed2006

The prediction of isotopic patterns in phenylpropanoids from their precursors and the mechanism of the NIH-shift: basis of the isotopic characteristics of natural aromatic compounds.

The theoretical 2H-distribution in the aromatic ring of phenylpropanoids can be predicted from that of their precursors--erythrose-4-phosphate, phosphoenolpyruvate and NADPH--and by invoking the mechanism of the NIH-shift and implied deuterium isotope effects. For each position in the non-oxygenated ring, the predicted natural 2H-abundance is in excellent agreement with experimental data obtained from quantitative 2H NMR-measurements on natural compounds, especially concerning the relative 2H-abundances p > o > or = m. For the p-hydroxylated derivatives, the experimentally determined 2H-abundance sequence order m > o can also be deduced, assuming an anisotropic migration (intramolecular isotope effect) of the p-hydrogen atom to the two differently 2H-substituted m-positions during the NIH-shift (intramolecular hydrogen transfer) and an in vivo deuterium kinetic isotope effect of approximately 1.20 on the final hydrogen elimination from the proposed ketodiene intermediate. The predicted 2H-distribution pattern of methyl salicylate 10, a representative of an o-hydroxylated natural compound, is in excellent agreement with that reported from 2H NMR analyses. However, for salicyl alcohol, minor differences between the theoretical and experimentally determined pattern are found that cannot yet be satisfactorily explained. On the other hand, a very good agreement is found between the theoretical and experimental pattern of coumarin, provided a deuterium kinetic isotope effect of approximately 1.30 is assumed for the elimination of the H-atoms from the ketodiene intermediate. The secondary m-hydroxylation of p-coumaric acid in the biosynthesis of vanillin seems to proceed without large isotope effects. Parallel differences are also observed for the 18O-kinetic isotope effects on the corresponding monooxygenase-catalysed reactions. The results demonstrate convincingly that the mechanisms of these general reactions of the phenylpropanoid biosynthetic pathway are identical and follow general principles. Small observed differences between the 2H-patterns of individual natural aromatic compounds originating from the same hydroxylation type can therefore be assigned to differences of the patterns of the precursors, the extent and the orientation of the hydrogen migration, and the kinetic isotope effect on the final hydrogen elimination. The evidence for the existence of general systematic rules governing isotopic patterns in the shikimic acid pathway and its subsequent reactions is further supported by the recently reported 13C-distribution pattern of vanillin, which is also in agreement with that predicted from the precursors. Hence, it is apparent that the systematics of the isotope patterns of phenylpropanoids are in line with the generally accepted biosynthetic reactions in the shikimic acid pathway and that this knowledge can strengthen their value as an essential support for the distinction of natural and synthetic aromatic compounds.

Benzaldehydes↗
PubMed1981

Comparison of dominant lethal and heritable translocation methodologies.

Groups of male Alderly Park mice of proven fertility were dosed by gavage for 5 consecutive days per week for 8 weeks or 5 consecutive days only with 100 or 150 mg/kg body weight ethyl methanesulphonate (EMS) or by intraperitoneal injection once a week for 8 weeks or once only with 500 mg/kg shikimic acid. Animals dosed in this manner were compared in the dominant lethal and heritable translocation assays. Animals were mated for 2 consecutive weeks following the 8-week treatment and for 8 consecutive weeks after the 1-week treatment: regimes which were thus non-specific and specific respectively for the stages of spermatogenesis. An additional method of measuring dominant lethality involving counting uterine scars after weaning (Soares (1972) Mutation Res., 16, 425-427) was used and also compared with the conventional method. EMS was clearly confirmed as a mutagen but this was not the case for shikimic acid. For screening purposes the dominant lethal 8-week mating assay was much more efficient in return for the same effort for detecting mutagenic responses than an 8-week mating heritable translocation assay, since the induction of dominant lethal effects paralleled the induction of heritable translocations. 8-week treatment with EMS showed increased dominant lethality but severely reduced fertility and the small numbers of male offspring born made potential heritable effects difficult to assess. The 1-week treatment with EMS produced both dominant lethal and heritable effects. Soares' method can be useful for determining dominant lethal effects in a heritable translocation assay. The "sieving" method of mating to determine partial and total sterility questions the necessity for a negative control in a heritable translocation study.

Animals↗
PubMed2002

Differential production of meta hydroxylated phenylpropanoids in sweet basil peltate glandular trichomes and leaves is controlled by the activities of specific acyltransferases and hydroxylases.

Sweet basil (Ocimum basilicum) peltate glandular trichomes produce a variety of small molecular weight phenylpropanoids, such as eugenol, caffeic acid, and rosmarinic acid, that result from meta hydroxylation reactions. Some basil lines do not synthesize eugenol but instead synthesize chavicol, a phenylpropanoid that does not contain a meta hydroxyl group. Two distinct acyltransferases, p-coumaroyl-coenzyme A:shikimic acid p-coumaroyl transferase and p-coumaroyl-coenzyme A:4-hydroxyphenyllactic acid p-coumaroyl transferase, responsible for the production of p-coumaroyl shikimate and of p-coumaroyl 4-hydroxyphenyllactate, respectively, were partially purified and shown to be specific for their substrates. p-Coumaroyl-coenzyme A:shikimic acid p-coumaroyl transferase is expressed in basil peltate glands that are actively producing eugenol and is not active in glands of noneugenol-producing basil plants, suggesting that the levels of this activity determine the levels of synthesis of some meta-hydroxylated phenylpropanoids in these glands such as eugenol. Two basil cDNAs encoding isozymes of cytochrome P450 CYP98A13, which meta hydroxylates p-coumaroyl shikimate, were isolated and found to be highly similar (90% identity) to the Arabidopsis homolog, CYP98A3. Like the Arabidopsis enzyme, the basil enzymes were found to be very specific for p-coumaroyl shikimate. Finally, additional hydroxylase activities were identified in basil peltate glands that convert p-coumaroyl 4-hydroxyphenyllactic acid to its caffeoyl derivative and p-coumaric acid to caffeic acid.

Acyl Coenzyme A↗
PubMed1969

Phenol biosynthesis in higher plants. Gallic acid.

The biosynthesis of gallic acid in a number of higher plants was investigated by using l-[U-(14)C]phenylalanine, (-)-[G-(14)C]shikimic acid, d-[1-(14)C]glucose and d-[6-(14)C]glucose as tracers. The results are compared with those obtained similarly for caffeic acid and are interpreted in terms of the dehydrogenation of 5-dehydroshikimic acid as a normal route of metabolism for gallic acid.

Cinnamates↗
PubMed1995

Molecular analysis of genes encoding phenazine biosynthesis in the biological control bacterium. Pseudomonas aureofaciens 30-84.

The DNA sequence of five contiguous open reading frames encoding enzymes for phenazine biosynthesis in the biological control bacterium. Pseudomonas aureofaciens 30-84 was determined. These open reading frames were named phzF, phzA, phzB, phzC and phzD. Protein PhzF is similar to 3-deoxy-D-arabino-heptulosonate-7-phosphate synthases of solanaceous plants. PhzA is similar to 2,3-dihydro-2,3-dihydroxybenzoate synthase (EntB) of Escherichia coli. PhzB shares similarity with both subunits of anthranilate synthase and the phzB open reading frame complemented an E. coli trpE mutant deficient in anthranilate synthase activity. Although phzC shares little similarity to known genes, its product is responsible for the conversion of phenazine-I-carboxylic acid to 2-hydroxy-phenazine-I-carboxylic acid. PhzD is similar to pyridoxamine phosphate oxidases. These results indicate that phenazine biosynthesis in P. aureofaciens shares similarities with the shikimic acid, enterochelin, and tryptophan biosynthetic pathways.

Amino Acid Sequence↗
PubMedDate not supplied

Modulation of phosphoenolpyruvate synthase expression increases shikimate pathway product yields in E. coli.

Product yields in microbial synthesis are ultimately limited by the mechanism utilized for glucose transport. Altered expression of phosphoenolpyruvate synthase was examined as a method for circumventing these limits. Escherichia coli KL3/pJY1.216A was cultured under fed-batch fermentor conditions where glucose was the only source of carbon for the formation of microbial biomass and the synthesis of product 3-dehydroshikimic acid. Shikimate pathway byproducts 3-deoxy-D-arabino-heptulosonic acid, 3-dehydroquinic acid, and gallic acid were also generated. An optimal expression level of phosphoenolpyruvate synthase was identified, which did not correspond to the highest expression levels of this enzyme, where the total yield of 3-dehydroshikimic acid and shikimate pathway byproducts synthesized from glucose was 51% (mol/mol). For comparison, the theoretical maximum yield is 43% (mol/mol) for synthesis of 3-dehydroshikimic acid and shikimate pathway byproducts from glucose in lieu of amplified expression of phosphoenolpyruvate synthase.

Escherichia coli↗
PubMed1967

Observations on the biosynthesis of phytoterpenoid quinone and chromanol nuclei.

1. p-Hydroxy[U-(14)C]benzoic acid, except for loss of the carboxyl group, is effectively incorporated into the nucleus of ubiquinone and an unidentified prenylphenol by maize roots, maize shoots, french-bean leaves, french-bean cotyledons and Ochromonas danica. Plastoquinone, alpha-tocopherol, gamma-tocopherol and alpha-tocopherolquinone are all unlabelled from this substrate. The high radioactivity of the prenylphenol and its behaviour in a pulse-labelling experiment with maize shoots suggested that it may be a ubiquinone precursor. 2. Members of the 2-polyprenylphenol and 6-methoxy-2-polyprenylphenol series, compounds that are known ubiquinone precursors in Rhodospirillum rubrum, could not be detected in maize tissues, but possibly they may occur as their glycosides. 3. [G-(14)C]Shikimic acid is incorporated into the nuclei of phylloquinone, plastoquinone, alpha-tocopherolquinone, gamma-tocopherol, alpha-tocopherol and ubiquinone in maize shoots, showing that in plant tissues the nuclei of these compounds arise via the shikimic acid pathway of aromatic biosynthesis. 4. l-[U-(14)C]Phenylalanine and l-[U-(14)C]tyrosine are incorporated into plastoquinone, gamma-tocopherol, alpha-tocopherolquinone and ubiquinone. alpha-Tocopherol, which is absent from shoots incubated with l-[U-(14)C]tyrosine, is also labelled from l-[U-(14)C]phenylalanine. Degradation studies showed that there is little (14)C radioactivity in the terpenoid portions of the molecules and from this it is concluded that the aromatic portions of these amino acids are giving rise to the quinone and chromanol nuclei. 5. It is proposed that in maize the nucleus of ubiquinone can be formed from either phenylalanine or tyrosine by a pathway involving p-coumaric acid and p-hydroxybenzoic acid. Plastoquinone, tocopherols and tocopherolquinones are formed from tyrosine by some pathway in which the aromatic ring and C-3 of the side chain of this amino acid gives rise to the nucleus and one methyl substituent respectively of these compounds.

Benzoates↗
PubMed1994

Carbohydrate mobilization following shoot defoliation and decapitation in hybrid poplar.

The effects of shoot defoliation, decapitation, and disbudding on carbon mobilization were investigated in rooted cuttings of Populus maximowiczii x nigra L. 'MN9'. Ten days after complete shoot defoliation or decapitation, the stem starch concentration of treated plants declined to one-half that of intact plants, and there were similar or greater reductions in the concentrations of glucose, fructose, sucrose, galactose, and shikimic acid. Partial shoot defoliation (50%) and complete disbudding had no effect on stem starch concentration, but stem sucrose concentration was reduced in all treatments. Sucrose depletion preceded and may have induced other changes in the carbon status of plants subjected to leaf or shoot removal. Four days after shoot decapitation, the sucrose concentration of roots of treated plants was reduced to 25% of that of intact plants. However, the concentrations of fructose and glucose increased in the roots of treated plants and was followed by the accumulation of shikimic acid, salicyl alcohol, unknown compound A and salicin. The possible role of increased concentrations of root organic solutes in the water relations and regrowth process of decapitated plants is discussed.

Journal Article↗
PubMedDate not supplied

Tannins and related compounds: killing of amastigotes of Leishmania donovani and release of nitric oxide and tumour necrosis factor alpha in macrophages in vitro.

The antileishmanial and immunomodulatory potencies of a series of 28 polyphenols were evaluated in terms of extra- and intracellular leishmanicidal activity and macrophage activation for release of nitric oxide (NO), tumour necrosis factor (TNF) and interferon (IFN)-like properties. For this, several functional bioassays were employed including an in vitro model for leishmaniasis in which murine bone marrow-derived macrophages (BMMphi) were infected with the obligate intracellular parasite Leishmania donovani, an extracellular Leishmania proliferation assay, a fibroblast-lysis assay (TNF-activity), and a biochemical assay for NO. Except for gallic acid, its methyl ester, shikimic acid and catechin (EC50 25.8-67.9 nM) all polyphenols tested significantly inhibited the intracellular survival of L. donovani amastigotes (EC50 0.4-13.9 nM) when compared with the clinically used agent, sodium stibogluconate (EC50 10.6 nM). In contrast, none of the samples proved to be directly toxic for the extracellular promastigote form of the parasite. Noteworthy, the phenolic samples showed only moderate or no cytotoxicity against the murine host cells (EC50 10 to >144 nM). Although NO is an important effector molecule in macrophage microbicidal activity, the inducing potential of the test compounds for its release was found to be very moderate ranging from 7-54 microM (IFN-gamma/LPS 119 microM). On the other hand, inhibition of NO production had no apparent effect on intracellular leishmanicidal activity of polyphenols. Their in vitro TNF-inducing potential producing 50% lysis in murine L929 cells increased in the order of simple phenols and flavanols (34-48 U/ml) < A-type proanthocyanidins (53-80 U/ml) < B-type proanthocyanidins (64-200 U/ml) < hydrolyzable tannins (287-350 U/ml) at the host cell subtoxic concentration of 50 microg/ml. Furthermore, gallic acid and some hydrolyzable tannins showed appreciable IFN-like activities (14-23 U/ml) as reflected by inhibition of the cytopathic effect of encephalomyocarditis virus on fibroblast L 929 cells. The results provide a rational basis for the recorded anti-infectious efficacy of traditionally used herbal medicines containing tannins in vivo, in the light of both only moderate direct antimicrobial activities of distinct polyphenols in vitro and the limited knowledge on their uptake in humans.

Animals↗
PubMedDate not supplied

Ubiquinone synthesis by Pneumocystis carinii: incorporation of radiolabeled polyprenyl chain and benzoquinone ring precursors.

Radiolabeled mevalonic acid was incorporated in vitro into Pneumocystis carinii ubiquinone homologs, CoQ9 and CoQ10, demonstrating the isoprenoid branch pathway forming the polyprenyl chain of ubiquinone is functional in the organism. Radiolabeled shikimic acid, tyrosine and p-hydroxybenzoic acid were also incorporated into the two ubiquinone homologs, indicating that P. carinii also possessed the biochemical pathway for de novo synthesis of the CoQ benzoquinone ring.

Coenzymes↗
PubMed1983

Thiamine pyrophosphate requirement for o-succinylbenzoic acid synthesis in Escherichia coli and evidence for an intermediate.

Cell-free extracts of various strains of Escherichia coli synthesize the menaquinone biosynthetic intermediate o-succinylbenzoic acid (OSB) when supplied with chorismic acid, 2-ketoglutaric acid, and thiamine pyrophosphate (TPP). To assay for OSB synthesis, 2-[U-14C]ketoglutaric acid was used as substrate, and the synthesized OSB was examined by radiogas chromatography (as the dimethyl ester). [U-14C]Shikimic acid also gave rise to radioactive OSB if the cofactors necessary for enzymatic conversion to chorismic acid were added. Use of 2-[1-14C]ketoglutaric acid does not give rise to labeled OSB. In the absence of TPP during the incubations, OSB synthesis was much reduced; these observations are consistent with the proposed role for the succinic semialdehyde-TPP anion as the reagent adding to chorismic acid. Extracts of cells from menC and menD mutants did not form OSB separately, but did so in combination. There was evidence for formation of a product, X, by extracts of a menC mutant incubated with chorismic acid, TPP, and 2-ketoglutaric acid; X was converted to OSB by extracts of a menD mutant. It appears that the intermediate, X, is formed by one gene product and converted to OSB by the second gene product.

Chorismic Acid↗