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PubMedDate not supplied

[The nature of melanin pigments from some micro- and macromycetes].

New inhibitors of melanin formation by micromycetes Aspergillus carbonarius, Alternaria alternata, and Paecilomyces variotii and basidiomycetes Inonotus obliquus and Phellinus robustus were found. Precursors of melanin pigments were isolated and identified. p-Hydroxybenzoic acid was identified among the products of alkaline degradation of melanin formed by micromycetes, whereas in the case of macromycetes this was protocatechuic acid. Therefore, melanins of the former were found to belong to the dihydronaphthalene group, whereas those of the latter belong to catechols.

Basidiomycota↗
PubMedDate not supplied

Variability in the enzyme properties of Pseudomonas aeruginosa strain 2x oxidizing p-xylene.

A culture of Pseudomonas aeruginosa 2x was observed for its spontaneous variability for growth on p-xylene and the intermediate products of its metabolism. The highest variability was found for ability to grow on p-xylene and pyrocatechol, and a variability an order of magnitude lower was found for ability to grow on protocatechuate and p-toluate. No variability was found for the character "ability to grow on p-hydroxybenzoate." The activity of the key enzymes for the oxidation of p-xylene was studied in p-xylene-negative strains. The difference between the p-xylene-positive wild type strain and the spontaneous p-xylene-negative strains was found to be linked to changes in the regulatory mechanisms for several enzymes: p-xylene methylhydroxylase and the enzymes involved in the breakdown of the aromatic ring. In addition, the appearance of p-xylene-negative strains was linked with a significant fall in the specific activity of all enzymes, except pyrocatechuase, which was replaced by metapyrocatechuase on a number of substrates.

4-Hydroxybenzoate-3-Monooxygenase↗
PubMed1999

[A study on chemical constituents in seeds of Crataegus pinnatifida Bge. var. major N. E. Br].

OBJECTIVE: To study the chemical constituents in the seed of Crataegus pinnatifida var. major. METHOD: Four compounds were isolated and identified by column chromatography and 1H, 13C-NMR data. RESULTS: The compounds obtained were identified as protocatechuic acid, gallic acid, catechol and p-hydroxybenzoic acid. CONCLUSION: All the compounds were isolated from this plant for the first time.

Catechols↗
PubMed2005

[Studies on the chemical constituents from Fructus Rubi].

Five compounds have been isolated from Fructus Rubi. On the basis of spectral analysis and physicochemical properties, their structures were establised as 4-hydroxy-3-methoxybenzoic acid (I), p-hydroxybenzoic acid (II), gallic acid (III), tiliroside (IV) and ellagic acid (V). I, II and III were found from the plant for the first time.

Benzopyrans↗
PubMedDate not supplied

[Degradation of aniline by Delftia tsuruhatensis 14S in batch and continuous processes].

A Delftia tsuruhatensis strain capable of consuming aniline as the sole source of carbon, nitrogen, and energy at concentrations of up to 3200 mg/l was isolated from activated sludge of purification works of OAO Volzhskii Orgsintez. The strain grew on pyrocatechol and p-hydroxybenzoic acid, but did not consume phenol, 2-aminophenol, 3-chloroaniline, 4-chloroaniline, 2,3-dichloroaniline, 2,4-dichloroaniline, 3,4-dichloroaniline, 2-nitroaniline, 2-chlorophenol, or aminobenzoate. Aniline is degraded by cleavage of the pyrocatechol aromatic ring at the ortho position. Cells were immobilized on polycaproamide fiber. It was shown that the strain degraded aniline at 1000 mg/l in a continuous process over a long period of time.

Aniline Compounds↗
PubMed2005

[Accumulation of phenolic acids in continuously cropped cucumber soil and their effects on soil microbes and enzyme activities].

The study showed that in solar greenhouse continuously cropped cucumber soil, phenolic acids p-hydroxybenzoic acid, ferulic acid and benzoic acid had an obvious accumulation with increasing cropping year, and their contents were significantly higher after continuously cropped for 5 approximately 9 years than for 1 approximately 3 years. With the increasing concentration of treated exogenous phenolic acids, the amounts of bacteria, actinomycetes, total microbes, ammonibacteria, and nitrifying bacteria in cucumber root area increased first, but decreased then. Soil bacteria and actinomycetes had the largest amount at the concentration of 80 microg phenolic acids x g(-1) soil, while soil fungi (including Fusarium and Phytophthora) increased rapidly when the concentration of phenolic acids was lower than 120 microg x g(-1) soil. With increasing phenolic acids concentration, soil enzyme activities also increased first but decreased then, with the peak values differed in different treatments.

Bacteria↗
PubMedDate not supplied

Comparative study of phenolic acids in pseudofruits of some species of roses.

A free and liberated by acid and alkaline hydrolysis phenolic acids from the hips of fourteen species of wildly growing roses were identifed and determined using SPE RP HPLC method. Eleven major phenolic acids (gallic, protocatechuic, gentisic, p-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic. p-hydroxyphenylacetic, salicylic) were quantitatively investigated. The amount of individual compounds ranged from 0.2 mg/g to 303.2 mg/g of dry material. Conjugated forms of phenolic acids were predominated in the fruits and they were hydrolyzed mainly to gallic acid (93-303 mg/g in dry plant material). The total amount of phenolic acid after hydrolyses was from 186.4 mg/g (R. inodora) to 466 mg/g (R. rugosa) of dry weight of plant material.

Animals↗
PubMedDate not supplied

The metabolism of p-methoxyamphetamine in dog and monkey. O-demethylation as a major route.

p-Hydroxyamphetamine (PHA) and p-hydroxybenzoic acid (PHBA) have been isolated by gas-liquid chromatography (GC) as urinary metabolites of p-methoxyamphetamine (PMA) in dogs and rhesus monkeys. The amounts of PMA excreted unchanged in the total 24-hr urine samples in dogs and monkeys were 26% and 3%, respectively, of the total administered doses. The amounts of the pharmacologically active metabolite PHA excreted in 24-hr urine samples were 13% in the dog and 44% in the monkey. In the dog, 72% of the PHA was present as free (unconjugated) PHA, whereas in the monkey the amount of PHA present in the free form was only 14%.

Amphetamines↗
PubMedDate not supplied

[Inhibition of the synthesis of isoprenoid compounds by phenol precursors of the benzoquinone ring of ubiquinone].

Effects of p-hydroxybenzoic and 3,4-dihydroxybenzoic acids on incorporation of I-14C-acetate into ubiquinone, sterols and nonsaponifiable lipid fraction were studied in liver slices. Inhibition of the label incorporation into all the isoprenoid-containing compounds studied was found, when these phenolic acids were used at I mM and higher concentrations. At the same time, inhibition of the ubiquinone biosynthesis was especially distinct although concentration of the substance was increased in mixtures in presence of phenolic acids as compared with controls.

Animals↗
PubMed1984

4-Thioflavins as active site probes of flavoproteins. General properties.

4-Thioflavins (oxygen at position 4 replaced by sulfur) have been studied as potential active site probes of flavoproteins. They react readily with thiol reagents, with large spectral changes, which should be useful for testing the accessibility of the flavin 4-position in flavoproteins. They have an oxidation-reduction potential at pH 7 of -0.055 V, approximately 0.15 V higher than that of native flavins. The spectral characteristics in the fully reduced state show two clear absorption bands, dependent on the ionization state (pK = 4.5). The lowest energy band of the neutral dihydroflavin has a maximum at approximately 485 nm while that of the anion is approximately 425 nm. This should be useful in defining the ionization state of the reduced flavin in flavoproteins. The spectral characteristics of the semiquinoid forms of 4-thioflavins have been determined bound to the apoproteins of flavodoxin and D-amino acid oxidase. The neutral radical has an absorption maximum at 730 nm, while the anion radical has an unusually sharp peak at 415 nm. The reduced forms of 4-thioflavins, free and enzyme bound, react with O2 to regenerate oxidized 4-thioflavin. Reduced 4-thio-FAD p-hydroxybenzoate hydroxylase, however, in its reaction with O2, undergoes a substantial conversion to the native FAD-enzyme. 4-Thioflavins are unusually susceptible to attack by nucleophiles such as hydroxylamine and amines to form the respective 4-hydroxyimino- and 4-aminoflavins, offering the possibility of forming stable covalent flavin-protein linkages with suitably positioned protein residues. Thiols also react with 4-thioflavins, promoting their conversion to the normal (4-oxo) flavin coenzymes. Such reactivity has been found with the apoenzymes of glucose oxidase and lactate oxidase, providing evidence for a thiol residue in the active site of these enzymes.

4-Hydroxybenzoate-3-Monooxygenase↗
PubMed1984

4-Thioflavins as active site probes of flavoproteins. Reactions with sulfite.

4-Thioflavins react with sulfite under aerobic conditions to yield highly fluorescent products with absorption maxima around 410 nm. These products have been identified as 4-hydroxy-4-sulfonylflavins, and have been shown to arise from a series of reactions following the O2-dependent reoxidation of an intermediate with absorption maxima at 363 and 465 nm. Under anaerobic conditions, the same intermediate is formed, but decays to a 350 nm absorbing species, which is probably the N(5)-sulfite adduct of 4-thioflavin. A plausible mechanism is described for the formation of the derivatives, and several of their chemical and physical properties are described. Distinctly different results between different proteins are obtained when sulfite reacts with enzyme-bound 4-thioflavins. 4-Thio-FAD-D-amino acid oxidase and 4-thio-FMN-lactate oxidase react rapidly to yield the N(5)-sulfite adducts, as occurs with the native enzymes. 4-Thio-FAD-p-hydroxybenzoate hydroxylase reacts slowly in a manner paralleling the reaction with the free 4-thioflavins.

4-Hydroxybenzoate-3-Monooxygenase↗
PubMed1983

A critical comment on the use of the plate diffusion test for QSAR considerations.

The plate diffusion test is widely used for the screening of possible antimicrobials. Antibiograms play an important role for the selection of suitable antibiotics in the routine treatment of infections. We are able to show with a series of O-acylated 4-hydroxybenzoic acids that the percentage of the dose which did not diffuse into the agar plate depends on physico-chemical parameters of the compounds. The amount of the residue is linearly related both to the lipophilic behaviour expressed by the partition coefficients (log Pf) and the spatial extension expressed as Van der Waals Volumes (Vw). The plate diffusion test should be used with caution for studies of QSAR and also relative comparisons of activities.

Anti-Bacterial Agents↗
PubMed1983

Aromatic ring cleavage of protocatechuic acid by the white-rot fungus Pleurotus ostreatus.

In Pleurotus ostreatus protocatechuic acid is degraded by protocatechuate 3,4-dioxygenase (protocatechuate: oxygen 3,4-oxidoreductase, EC 1.13.11.3) via "intradiol" cleavage of aromatic ring to form beta-carboxy-cis,cis-muconic acid. The enzyme was isolated from the mycelium induced with p-hydroxybenzoic acid. An about 460-fold purification of the enzyme was achieved by ammonium sulphate fractionation, and DEAE-cellulose and Sephadex G-200 chromatography. The enzyme was homogeneous on analytical electrophoresis under non-denaturing conditions, whereas in the presence of sodium dodecyl sulphate several polypeptides of low molecular weight appeared additionally in trace amounts. Molecular weight of the enzyme, determined by gel filtration and electrophoresis was 200 000 and 205 000, respectively. The enzyme showed low substrate specificity, its pH optimum was 8.0 and Michaelis constant for protocatechuic acid was 14.2 microM.

Basidiomycota↗
PubMedDate not supplied

[Taxonomic study of "Citrobacter freundii" biochemical variants (author's transl)].

Biochemical variants (ornithine-decarboxylase-positive and beta-galactosidase-negative) of Citrobacter freundii were characterized using numerical taxonomy, determination of deoxyribonucleic acid (DNA) base composition and DNA-DNA hybridization. Three clusters were detected by numerical taxonomy based on the assimilation of 146 carbohydrates. The atypical strains were dispersed into two clusters along with typical C. freundii strains. Furthermore, m-hydroxybenzoate metabolism, determination of base composition and DNA reassociation show that all three clusters are closely related. Therefore, the biochemical variants form a biogroup within C. freundii rather than a separate species.

Base Composition↗
PubMed1978

The 4-hydroxybenzoate/4-aminophenazone chromogenic system used in the enzymic determination of serum cholesterol.

A single reagent, containing cholesterol oxidase, cholesterol esterase, peroxidase, 4-hydroxybenzoate, and 4-aminophenazone, is used in determining serum cholesterol. Analysis time is 15 min, and the standard curve is linear to 6.0 g/liter. Analytical recovery of cholesterol was 100.1 +/- 0.4%. Within-run precision (CV) was less than or equal to 1.4 1.4%, between-run less than or equal to 4.8%. Comparison with results by a Liebermann Burchard method [Clin. Chim. Acta 5, 637 (1960)] gave a linear regression of y = 1.08x--0.05, with a correlation coefficient (r) of 0.985. Comparison with the Roeschlau enzymic method [J. Clin. Chem. Clin. Biochem, 12, 226 (1974)] gave y = 1.02x + 0.01 (r = 0.958). Comparison with the enzymic method of Allain et al. [Clin. Chem. 20, 470 (1974)] gave y = 1.01x--0.00 (r = 0.995). The following substances do not interfere up to the indicated concentrations (mg/liter): hemoglobin (5000), bilirubin (100), reduced glutathione (150), l-cysteine (400), urea (3000), creatinine (200), uric acid (200), d-glucose (10000), L-ascorbic acid (50), acetylsalicylic acid (500), L-DOPA (10), ergothioneine (1000), 2,5-dihydroxybenzoic acid (20), and 3,4-dihydroxybenzoic acid (10). Stored in an amber-colored bottle, the working reagent is stable for three months at 2--8 degrees C and for three weeks at 25 degrees C.

Aminopyrine↗
PubMedDate not supplied

[Adaptation of yeasts of the genus Debaryomyces to protocatechuic acid].

Among five yeast strains belonging to the genus Debaryomyces that were unable of utilizing aromatic compounds (phenols and hydroxybenzoic acids), three strains, viz. D. kloeckeri BKM-Y-1044, D. marama BKM-Y-100 and D. marama BKM-Y-2045, were adapted to protocatechuic acid. The adapted yeasts utilized protocatechuic acid if its concentration in the medium was 0.1%, but did not utilize it, or did at a very low rate, if the concentration of protocatechuic acid was decreased to 0.05%. The mechanism of adaptation is rare mutations occurring in succession, and the process takes therefore several months. The adaptation seems to be based on reversion of inactivated genes for enzymes involved in the preparative metabolism of protocatechuic acid. Three typical yeast species of the Debaryomyces genus are proposed (D. hansenii, D. kloeckeri and D. konokotinae) which include all of the Debaryomyces species and strains available at the Institute of Microbiology of the USSR Academy of Sciences.

Adaptation, Physiological↗
PubMed1978

[High-performance liquid chromatography in the determination of organic acids in wine].

We shall distinguish the case of non aromatic organic acids from that one of phenolic acids. In the first one, we have applied to wines a method used for fruit-juices by Palmer and List, 1973. After contact of the wine with a strong acid resin, its is injected on anion exchange resin Aminex A 25 precolumn (formiate form) which retains all the organic acids. The precolumn is washed with water to eliminate neutral components, then connected with the chromatographic column which contains the same resin. The different acids are eluted with a solution of natrium formiate at 70 degrees C. They are detected by differential refractometry (galacturonic, lactic, malic, succinic, tartric acids) and by ultraviolet at 254 nm (shikimic acid). Beside these compounds which are identified by their retention volumes, others not yet attributed peaks are detected. The limits of detection are 2 mg/l for shikimic acid, 30 mg/l for tartric acid and 15 mg/l for the others. Analysis time is about one hour. In the case of phenolic acids, we extract them from wine by diethyl ether after saturation with NaCl or by demixtion. The determination of phenolic acids is done on the ether extract or on the organic layer of the demixtion. Chromatography is obtained on octadecylsilanised column (RP 18) with solvent gradient (from 10% methanol in KH2PO4O,1 M pH 2,1 to 60% methanol in the same buffer) and detection in ultraviolet at 254 nm. The knowledge of recovery of acids by diethyl ether or by demixtion permits to obtain their concentrations in wine. The different so determinated phenolic acids are: gallic, 4 hydroxybenzoic, cafeic, vanillic, syringic and para coumaric acids. We have applied these methods to 32 wines for phenolic acids and 80 wines for non aromatic acids. Some results are presented in the case of 24 wines issued from Gamay and 8 wines from Pinot and it appears that tartric and shikimic acids have more important average concentrations in the former than in the latter.

Acetates↗
PubMed1994

The blocking effect of phenolic acid on N-nitrosomorpholine formation in vitro.

Phenolic acids (PAs) are widely found in many daily consumed vegetables and fruits. The inhibitory effects of PAs on N-nitrosomorpholine (NMOR) formation in vitro under simulated gastric juice condition were studied. The results showed that the inhibitory potency of thirteen varieties of PAs differed greatly, which may be related to their chemical structures; the blocking rate (BR) of different kinds of PAs were as follows: caffeic acid, 92.5%; tannic acid, 90.0%; gallic acid, 86.8%; sinapinic acid, 86.2%; ferulic acid, 81.1%; chlorogenic acid, 69.4%; gentisic acid, 69.2%; syringic acid, 62.1%; protocatechuic acid, 56.0%; p-coumaric acid, 52.5%; vanillic acid, 35.4%; moreover, p-hydroxybenzoic acid and m-coumaric acid had the least blocking effect or even slight catalyzing effect. The results also demonstrated that amounts of NMOR formed were negatively correlated with molar ratio of PAs to nitrite and that the optimum pH for inhibition was between 2 and 3.

Carcinogens↗