SEARCH · PubMed Health

Results for “PYROCATECHOL”

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 109 records · Page 6Linked to original sources

PubMed1981

Cytomorphological study of cultured mammalian cells treated with benzaldehyde, catechol and their derivatives with special reference to inhibition of DNA synthesis.

Cytotoxicity and cytomorphological changes induced in cultured mammalian cells by the application of benzaldehyde, pyrocatechol and their derivatives were examined. Among the compounds tested, 3,4-dihydroxybenzaldehyde (protocatechualdehyde) and 1,2-dihydroxybenzene (pyrocatechol) produced cytomorphological changes characteristic of specific inhibitors of DNA synthesis in V79 cells and EJ-1 cells. However, they did not induce such changes in HeLa cells. 2,3-Dihydroxybenzaldehyde and catecholamines did not produce such characteristic changes in V79 cells. The cytological effects of protocatechualdehyde and pyrocatechol were confirmed by a study on the incorporation of 3H-precursors of DNA, RNA and protein into 3 cell lines.

Animals↗

PubMed1976

[Microbial breakdown of acid anilide fungicides (author's transl)].

o-Toluylanilide, 2.5-dimethylfuran-3-carboxanilide, 5.6-dihydro-2-methyl-1.4-oxathiine-3-carboxanilide and other acid anilides are systemic fungicides which act selectively on rusts and smuts. From garden soil a Nocardia sp. was isolated which can grow with acid anilide fungicides as the only source of carbon. From this Nocardia sp. it was possible to produce mutants which are blocked genetically at various steps of the breakdown pathway of these acid anilide fungicides. It was possible to follow the breakdown pathway with the aid of accumulates of the rough I strain and of the mutants as well as by growth and enzyme tests. Breakdown starts with hydrolytic splitting of the acid amide bond by an acylamidase. The acid components of the fungicides are accumulated in the medium; they do not affect the growth. The aniline component is oxidized to pyrocatechol by a dioxygenase. Methyl and chloro-derivatives of aniline which are formed in the soil due to the hydrolysis of herbicides and fungicides, are also converted into the respective pyrocatechol derivatives. By orthocleavage cis-cis muconic acid forms from pyrocatechol. This compound is metabolized into succinate and acetyl CoA via the beta ketoadipate pathway.

Amidohydrolases↗

PubMed1994

Accumulation of antifungal compounds in tea leaf tissue infected with Bipolaris carbonum.

Varietal resistance of tea towards Bipolaris carbonum was tested following detached leaf inoculation technique. Among the fourteen varieties tested, three were found to be highly susceptible, while other three were resistant. Leaf exudates and diffusates collected from the resistant varieties were more fungitoxic than those from the susceptible ones. Two antifungal compounds isolated from healthy and B. carbonum-infected tea leaves exhibited clear inhibition zones at RF 0.8 and 0.65, respectively, in a chromatographic bioassay. On the basis of their color reaction on TLC and UV-spectra these were identified to be catechin and pyrocatechol. Resistant and susceptible varieties accumulated 439-510 and 187-212 micrograms/g fresh mass tissue of pyrocatechol, respectively, 2 d after inoculation with B. carbonum, while a low concentration (45-58 micrograms/g) of this compound was detected in healthy leaf tissue.

Antifungal Agents↗

PubMed2002

Bacterial aerobic degradation of benzene, toluene, ethylbenzene and xylene.

Several aerobic metabolic pathways for the degradation of benzene, toluene, ethylbenzene and xylene (BTEX), which are provided by two enzymic systems (dioxygenases and monooxygenases), have been identified. The monooxygenase attacks methyl or ethyl substituents of the aromatic ring, which are subsequently transformed by several oxidations to corresponding substituted pyrocatechols or phenylglyoxal, respectively. Alternatively, one oxygen atom may be first incorporated into aromatic ring while the second atom of the oxygen molecule is used for oxidation of either aromatic ring or a methyl group to corresponding pyrocatechols or protocatechuic acid, respectively. The dioxygenase attacks aromatic ring with the formation of 2-hydroxy-substituted compounds. Intermediates of the "upper" pathway are then mineralized by either ortho- or meta-ring cleavage ("lower" pathway). BTEX are relatively water-soluble and therefore they are often mineralized by indigenous microflora. Therefore, natural attenuation may be considered as a suitable way for the clean-up of BTEX contaminants from gasoline-contaminated soil and groundwater.

Bacteria, Aerobic↗

PubMed2000

Some tryptophan pathways in the phytopathogen Xanthomonas oryzae pv. oryzae.

Xanthomonas oryzae pv. oryzae, the causal organism of bacterial blight of rice which produces leaf blight as well as kresek (wilt) symptoms in plants were tested for indole, auxin production in culture supplemented with L-tryptophan. On the basis of indoleacetic acid (IAA) production the isolates were grouped into IAA-positive and IAA-negative. Out of 17 isolates, 11 were IAA-positive while 6 were IAA-negative. The isolates metabolized tryptophan through two different routes and the isolates vary in the pathway of tryptophan utilization. The IAA-positive isolates converted tryptophan to IAA as the end product, whereas the IAA-negative isolates formed anthranilate as an intermediate metabolite and finally produced pyrocatechol via the kynurenine pathway. Quantification of tryptophan metabolism revealed that the maximum production of IAA and pyrocatechol in culture occurred during 2-d incubation at 30 +/- 2 degrees C.

Catechols↗

PubMed1995

Inhibition of adenylyl cyclase in rat striatal homogenates by combinations of dopamine and ferric iron compounds.

The adenylyl cyclase activity of homogenates of striatal tissue from rat brain has been used as a model to test the hypothesis that the products of the reaction of polyphenols with ferric iron compounds are toxic. Dopamine (DA), at levels that stimulate adenylyl cyclase, inhibited the activity in the presence of 2 mol of potassium ferricyanide (FC), methemoglobin or ferricytochrome c per mol of DA. Combinations of potassium ferrocyanide and DA were not inhibitory. Neither pyrocatechol nor hydroquinone stimulated the activity, but these polyphenols were inhibitory in the presence of FC. Tyramine, phosphorylated DA or phosphorylated pyrocatechol had no effect on the activity of the enzyme in the presence or absence of FC. Forskolin was unable to stimulate the adenylyl cyclase once the latter was inhibited by DA plus FC, and dithiothreitol could not reverse inhibition by DA plus FC. Incubation of DA with FC, in the absence of the homogenate, resulted in substances that were not inhibitory. These findings suggest that the polyphenols plus FC react to yield substances that inhibit the adenylyl cyclase by affecting the catalytic unit of the enzyme complex.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1995

Isolation and characterization of a tyrosinase from the skin of the white silky fowl (Gallina lanigera) employing copper saturated diethylaminoethyl-cellulose.

Tyrosinase was purified to apparent homogeneity from the skin of the White Silky fowl (Gallina lanigera). Under alkaline conditions copper ions from a complex with the diethylaminoethyl moiety of DEAE-cellulose, allowing the purification of the enzyme in a one step chromatography. In polyacrylamide gel electrophoresis containing sodium dodecyl sulfate the purified tyrosinase displays a single band with a relative molecular mass of 66,000 Da. The crystalline tyrosinase was obtained from 32-33% saturated solution of ammonium sulfate. The enzyme catalyzes the o-hydroxylation of L-tyrosine to L-dihydroxyphenylalanine as well as the oxidation of pyrocatechol to o-benzoquinone. For the pyrocatechol oxidation the Michaelis Menten constant Km, is calculated to be around 1.19 x 10(-3) M.

Animals↗

PubMed2004

Micellar electrokinetic chromatography at low pH with polyelectrolyte-coated capillaries.

The performance of capillaries coated with a poly(diallyldimethylammonium) (PDADMA) monolayer or poly(diallyldimethylammonium)-poly(styrenesulfonate) bilayer was investigated and compared under micellar electrokinetic chromatographic (MEKC) conditions. Both monolayer (positively charged) and bilayer (negatively charged) coatings with micellar (sodium dodecyl sulfate) electrolyte generated very stable and pH-independent cathodal electroosmotic flow (EOF). From the results obtained, it can be concluded that in a doubly coated capillary the second poly(styrenesulfonate) layer is replaced by sodium dodecyl sulfate micelles during flushing with micellar electrolyte. Consequently, in order to obtain a stable and pH-independent cathodal electroosmotic flow for the MEKC separations, the capillary coating with the second polyanion layer is not necessary. The importance of the PDADMA coating was illustrated by comparing MEKC separations of the common developing agents (hydroquinone, phenidone, pyrocatechol, pyrogallol and quinone) on a bare uncoated capillary with the coated capillary. The coating provides reproducible MEKC separations at low pH (pH 3.0) with relative standard deviation (R.S.D.) values for migration times and peak areas lower than 0.45 and 3.3%, respectively. Good linearities in the range from 5 x 10(-5) to 2 x 10(-3) mol l(-1) were obtained for all five compounds, with correlation coefficients higher than 0.998. The detection limits were in the range from 5 x 10(-6) mol l(-1) for pyrocatechol to 2 x 10(-5) mol l(-1) for quinone. The proposed MEKC system was applied to the determination of hydroquinone and phenidone in X-ray photographic developer solutions.

Calibration↗

PubMed1981

Comparison of alternative chromogens for renal immunohistochemistry.

Renal immunomicroscopy using enzyme labeled reagents has been shown to be a reliable method for the identification of immunoglobulins and complement in the routine evaluation of glomerular disease. However, the potential carcinogenicity of benzidine derivatives used in the procedure represents a major disadvantage of the technique. With a series of 55 renal biopsy specimens evaluated by light microscopy, immunofluorescence, and electron microscopy from patients with a variety of renal diseases, a study was done comparing aminoethylcarbazole and the Hanker-Yates reagent (p-phenylenediamine and pyrocatechol), chromogens chemically unrelated to benzidine. Aminoethylcarbazole was not suitable for renal immunomicroscopy, since in cases of antiglomerular basement membrane disease the color reaction product was finely granular at high magnification. Specimens immunostained with the Hanker-Yates reagent yielded permanent water insoluble reaction products and immunomicroscopic patterns identical to the results observed with immunofluorescence in all cases. To our knowledge, no carcinogenic properties have been identified for p-phenylenediamine or pyrocatechol. The Hanker-Yates reagent may be used routinely for renal enzyme immunomicroscopic studies with no currently identified carcinogenic hazard to laboratory personnel.

3,3'-Diaminobenzidine↗

PubMed2000

In vivo effects of phenolic compounds on blood parameters of a marine fish (Dicentrarchus labrax).

Sea bass (Dicentrarchus labrax) were injected intraperitoneally once (single dose) or three times (fractionated dose) with phenol or OH-phenols (hydroquinone, resorcinol, and pyrocatechol). On the basis of the lethal doses, OH-phenols were more toxic than phenol, and pyrocatechol was the most powerful compound. Hematological, metabolic and antioxidant blood parameters were measured 3 days after the end of the treatment. Metabolic variations as specific effects on erythrocytes were revealed and differences between single and fractionated doses were observed. OH-phenols-treated fish showed disorders in the metabolic toxicity indicators as hypoglycemia, low blood urea nitrogen level (BUN) and decrease of alkaline phosphatase activity (ALP). In addition, quantitative structure-activity relationships were developed using the n-octanol:water partition coefficient (log K(ow)). Positive correlations were found with ALP, plasma glucose and hemoglobin.

Alkaline Phosphatase↗

PubMed2003

Amperometric biosensors based on recombinant laccases for phenols determination.

Graphite (GE) or printed graphite electrode (PGE) based biosensors containing recombinant fungal laccase Polyporus pinsitus (rPpL), and Myceliophthora thermophila (rMtL) were developed. The enzymes were immobilized using bovine serum albumin and glutaraldehyde. At pH 5.5 and -0.1 V, the calibration graphs of GE based biosensors were hyperbolic if pyrocatechol was used. The concentration of substrate that results in 50% of steady-state response (EC(50)) was 0.7 mM and sensitivity (S) was 3.8 mA/M. The sensitivity increased up to 4 A/M if larger amount of rPpL was used. The sensitivity of biosensors changed little during 9 days of exploitation, but decreased at longer time. The PGE based biosensors were mounted into the flow-through cell and calibrated under kinetic regime. EC(50) of the biosensors containing rPpL varied from 0.6 to 4.0 mM and sensitivity varied from 0.11 to 1.9 mA/M. The response of biosensor containing thermostable laccase rMtL was less, but response saturated at larger pyrocatechol concentration. The sensitivity changed little during 6 days. Both type of biosensors responded also to 1-naphthol, o-phenylenediamine, guaiacol, o-anizidine, benzidine. The experiments demonstrate recombinant laccases application to biosensor engineering and their use to phenol and related compound determination under steady-state and flow-through regimes.

Adsorption↗

PubMed2001

Mut-Test to detect substances suppressing spontaneous mutation due to oxidative damage.

Since it has been considered that suppression of spontaneous mutation in cells is related to suppression of spontaneous carcinogenesis, it is significant to detect substances which suppress spontaneous mutation in bacterial cells such as Escherichia coli and Salmonella typhimurium in the environment. However, since the frequency of spontaneous mutation in bacteria is usually very low, generally 10(-8)-10(-10),it is difficult to determine significant suppressive ability of such substances on spontaneous mutation. A new method, Mut-Test, was developed by us, applying Luria & Delbruck fluctuation test, to detect substances which suppress spontaneous mutation using E. coli mutT mutant in which spontaneous mutation frequency due to oxidative damage is enhanced to approximately 500-1000 times of the wild type strain. Suppressive abilities of two hydroxyl radical scavengers: D(-)-mannitol and thiourea, were examined and clear positive results were obtained, suggesting that the radical scavengers are suitable as the positive control for the test. Using Mut-Test, suppressive abilities of four vitamins: L-ascorbic acid, beta-carotene, folic acid and riboflavin; 10 polyphenols: caffeic acid, ellagic acid, (-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin, gallic acid, pyrocatechol, pyrogallol, quercetin and tannic acid which are recognized as antimutagens, were examined. Furthermore, the concentrations for 50% of suppressive abilities of five positive samples, L-ascorbic acid, folic acid, caffeic acid, pyrocatechol and pyrogallol were compared. Negative results were obtained in nine samples, riboflavin, tannic acid, etc. suggesting that their antimutagenic effect on cells may not be related to oxidative damage in cells.

Antimutagenic Agents↗

PubMed2001

Synthesis and molecular structures of some new titanium(IV) aryloxides.

The coordination chemistry of model phenolic ligands (pyrocatechol, salicylic acid, and 2,2'-biphenol) that are able to form respectively five-, six-, or seven-membered rings with titanium(IV) alkoxides is investigated. With pyrocatechol, a polynuclear complex containing 10 Ti atoms was characterized with a not very common doubly bridging mu3-(O,O,O',O') coordination mode. With salicylic acid, a monomeric tris(chelate) complex was obtained. With 2,2'-biphenol, a polynuclear complex containing six Ti atoms was obtained showing both mu2-(O,O') and mu2-(O,O,O') coordination modes for the ligands. Intermolecular interactions in the solid state for these three new compounds are also quantitatively discussed using the partial charge model.

Catechols↗

PubMedDate not supplied

[Inhibition of the peroxidase-catalyzed oxidation of chromogenic substrates by alkyl-substituted diphenols].

A comparative kinetic study of the peroxidase oxidation of three chromogenic substrates--2,2'-azino-bis(3-ethyl-2,3-dihydrobenzothiazoline-6-sulfonic acid), o-phenylenediamine (PDA), and 3,3',5,5'-tetramethylbenzidine--inhibited by trimethylhydroquinone and six tert-butylated pyrocatechols (InH) was carried out at 20 degrees C in 0.015 M phosphate-citrate buffer (pH 6.0) containing organic cosolvents (0-10% ethanol or DMF). The inhibitors were quantitatively characterized by the inhibition constants (Ki), the duration of the lag period in the oxidation product formation (delta tau), and the stoichiometric coefficient of inhibition that specifies the number of radicals terminated by one InH molecule (f). The inhibition could be competitive, noncompetitive, mixed, or uncompetitive, which depended on the nature and structure of the chromogenic substrate-diatomic phenol pair. Various substrate-diatomic phenol pairs exhibited Ki values within the range of 11-240 microM and f values from 0.7 to 2.6. The absence of a lag period was characteristic of oxidation of the substituted o-phenylenediamine-substituted pyrocatechol. The total kinetic parameters and properties of the components allowed us to suggest six chromogenic substrate-substituted diatomic phenol pairs for use in test systems for the determination of antioxidant activity in human body fluids, natural biological preparations, and food. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 5; see also http: // www.maik.ru.

Benzidines↗

PubMed2002

Adsorption and detection of some phenolic compounds by rice husk ash of Kenyan origin.

Rice husk ash (RHA) obtained from a rice mill in Kenya has been used as an inexpensive and effective adsorbent (and reagent) for the removal (and detection) of some phenolic compounds in water. The abundantly available rice mill waste was used in dual laboratory-scale batch experiments to evaluate its potential in: (i) the removal of phenol, 1,3-dihydroxybenzene (resorcinol) and 2-chlorophenol from water; and (ii) the detection of 1,2-dihydroxybenzene (pyrocatechol) and 1,2,3-trihydroxybenzene (pyrogallol) present in an aqueous medium. The studies were conducted using synthetic water with different initial concentrations of the phenolic compounds. The effects of different operating conditions (such as contact time, concentration of the phenolic compounds, adsorbent quantity, temperature, and pH) were assessed by evaluating the phenolic compound removal efficiency as well as the extent of their color formation reactions (where applicable). RHA exhibits reasonable adsorption capacity for the phenolic compounds and follows both Langmuir and Freundlich isotherm models. Adsorption capacities of 1.53 x 10(-4), 8.07 x 10(-5), and 1.63 x 10(-6) mol g(-1) were determined for phenol, resorcinol and 2-chlorophenol, respectively. Nearly 100% adsorption of the phenolic compounds was possible and this depended on the weight of RHA employed. For the detection experiments, pyrocatechol and pyrogallol present in water formed coloured complexes with RHA, with the rate of colour formation increasing with temperature, weight of RHA, concentration of the phenolic compounds and sonication. This study has proven that RHA is a useful agricultural waste product for the removal and detection of some phenolic compounds.

Adsorption↗

PubMed1979

Biodegradation of C-labeled model and cornstalk lignins, phenols, model phenolase humic polymers, and fungal melanins as influenced by a readily available carbon source and soil.

After 6 months of incubation in a fertile neutral sandy loam, about 48% of the ring carbons and 2-carbons and 60% of the OCH(3) carbons of specifically labeled coniferyl alcohol had evolved as CO(2). After 1 year, corresponding values were 55 and 65%. When coniferyl alcohol units were linked into model and cornstalk lignins, about 23% of the ring carbons and 2-carbons and 39% of the OCH(3) carbons had evolved as CO(2) after 6 months. After 1 year, corresponding values were about 28 and 46%. The addition of orange leaves (0.5%, wt/wt) after 6 months did not significantly increase the evolution of CO(2). Addition of orange leaves (0.5%, wt/wt) with specifically C-labeled pyrocatechol, coumaryl alcohol, model lignins, humic acid-type phenolic polymers and of uniformly C-labeled fungal melanins did not increase labeled C losses or C losses from the orange leaves. Decomposition of protein and pyrocatechol linked into model humic acid polymers, coniferyl alcohol C in model lignins, and Eurotium echinulatum melanin in six soils varied from 2 to 14%. Significant differences in C losses were related to soils and were not influenced by orange leaf applications.

Journal Article↗

PubMed1963

Studies on coccidioides immitis. II. Physiological studies on in vitro spherulation.

Brooks, Lula D. (Arizona State University, Tempe) and William T. Northey. Studies on Coccidioides immitis. II. Physiological studies on in vitro spherulation. J. Bacteriol. 85:12-15. 1963.-Studies on the amino acids assayed in Edamine revealed that the amino acids phenylalanine, tyrosine, and tryptophan, in addition to the amino acid derivatives dihydroxyphenylalanine (DOPA), epinephrine, tyramine monohydrochloride (tyramine HCl), and pyrocatechol play an important role in the Coccidioides immitis conversion process. In the presence of phenylalanine, tyrosine, tryptophan, DOPA, pyrocatechol, dextrose, and biotin, conversion as well as maturation was demonstrated. However, in epinephrine and tyramine HCl combinations, conversion occurred without maturation of the spherules. The availability of increased amounts of melanin precursors is suggested as a possible explanation for the increased susceptibility of the dark-skinned races to disseminated coccidioidomycosis. Conversion and maturation were also noted when lactic and fumaric acids served as carbon sources. The conversion of a limited number of arthrospores to spherules and their subsequent maturation in the presence of only phenol and biotin suggest the possibility that the key to the C. immitis conversion process lies in the availability of certain ring structures.

Biotin↗

PubMed1992

Platelet aggregation inhibitors from Populus sieboldii Miquel.

The water extract of Populus sieboldii Miquel (Salicaceae) inhibited arachidonic acid-induced platelet aggregation. Pyrocatechol and salicyl alcohol were isolated as active constituents. Pyrocatechol showed an inhibitory effect on platelet aggregation induced by arachidonic acid with IC100 value of 4 microM, which was 25 times more potent than aspirin.

Drugs, Chinese Herbal↗