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At least 19 recordsLinked to original sources
PubMed1985

Contact allergy to 3-methylol phenol, 2,4-dimethylol phenol and 2,6-dimethylol phenol.

Thirteen patients with contact allergy to phenol-formaldehyde resins (P-F-R) were patch tested with 3-methylol phenol, 2,4-dimethylol phenol and 2,6-dimethylol phenol. Nine patients reacted to at least 1 compound, all giving positive test responses to 2,4-dimethylol phenol. Seven patients reacted simultaneously to 2,6-dimethylol phenol while only 1 patient reacted to 3-methylol phenol. Negative test responses were noted in 20 controls. Chemical investigation by high pressure liquid chromatography indicated that the compounds tested were pure and separable. The 3 reported sensitizers may, theoretically, be generated during the manufacture of P-F-R. 2,4-Dimethylol phenol and 2,6-dimethylol phenol have been demonstrated and there has been chromatographic evidence of 3-methylol phenol in the P-F-R used in the routine test series at the department.

Benzyl Alcohols↗
PubMed2000

Three types of phenol and p-cresol catabolism in phenol- and p-cresol-degrading bacteria isolated from river water continuously polluted with phenolic compounds.

A total of 39 phenol- and p-cresol-degraders isolated from the river water continuously polluted with phenolic compounds of oil shale leachate were studied. Species identification by BIOLOG GN analysis revealed 21 strains of Pseudomonas fluorescens (4, 8 and 9 of biotypes A, C and G, respectively), 12 of Pseudomonas mendocina, four of Pseudomonas putida biotype A1, one of Pseudomonas corrugata and one of Acinetobacter genospecies 15. Computer-assisted analysis of rep-PCR fingerprints clustered the strains into groups with good concordance with the BIOLOG GN data. Three main catabolic types of degradation of phenol and p-cresol were revealed. Type I, or meta-meta type (15 strains), was characterized by meta cleavage of catechol by catechol 2,3-dioxygenase (C23O) during the growth on phenol and p-cresol. These strains carried C23O genes which gave PCR products with specific xylE-gene primers. Type II, or ortho-ortho type (13 strains), was characterized by the degradation of phenol through ortho fission of catechol by catechol 1,2-dioxygenase (C12O) and p-cresol via ortho cleavage of protocatechuic acid by protocatechuate 3,4-dioxygenase (PC34O). These strains carried phenol monooxygenase gene which gave PCR products with pheA-gene primers. Type III, or meta-ortho type (11 strains), was characterized by the degradation of phenol by C23O and p-cresol via the protocatechuate ortho pathway by the induction of PC34O and this carried C23O genes which gave PCR products with C23O-gene primers, but not with specific xylE-gene primers. In type III strains phenol also induced the p-cresol protocatechuate pathway, as revealed by the induction of p-cresol methylhydroxylase. These results demonstrate multiplicity of catabolic types of degradation of phenol and p-cresol and the existence of characteristic assemblages of species and specific genotypes among the strains isolated from the polluted river water.

Journal Article↗
PubMed1986

Sensitizing capacity of 2-methylol phenol, 4-methylol phenol and 2,4,6-trimethylol phenol in the guinea pig.

The sensitizing capacities of 2-methylol phenol (2-MP), 4-methylol phenol (4-MP) and 2,4,6-trimethylol phenol (2,4,6-MP) were investigated with the guinea pig maximization test. These compounds are known sensitizers in phenol-formaldehyde resins. The study was performed in order to assess and compare the degree of the sensitizing capacities of these chemically related substances. The animals were also rechallenged with the sensitizer and 5 chemically related compounds in order to study the cross-reaction patterns. 2-MP was demonstrated to be a strong sensitizer, 4-MP a moderate sensitizer and 2,4,6-MP a weak sensitizer. With 2-MP as the sensitizer, o-cresol and 2,4-dimethyl phenol were possible cross-reacting substances. p-cresol and 2,4,-dimethylol phenol were possible cross-reacting compounds for 4-MP. The chemical investigation by high pressure liquid chromatography indicated that the compounds tested were pure and separable.

Animals↗
PubMed2000

Phenolic compounds and squalene in olive oils: the concentration and antioxidant potential of total phenols, simple phenols, secoiridoids, lignansand squalene.

The aim of this study was to evaluate the phenolic antioxidant and squalene content in a range of olive and seed oils. A mean of 290 +/- 38 (SEM) mg squalene/100 g was detected. However, while there was a weak significant difference between extra virgin (424 +/- 21 mg/kg) and refined virgin (340 +/- 31 mg/100 g; P<0.05) olive oils, highly significant differences were evident between extra virgin olive oils (P<0.0001) refined virgin olive oils (P<0.0001) and seed oils (24 +/- 5 mg/100 g). While seed oils were devoid, on average, the olive oils contained 196 +/- 19 mg/kg total phenolics as judged by HPLC analysis, but the value for extra virgin (232 +/- 15 mg/kg) was significantly higher than that of refined virgin olive oil (62 +/- 12 mg/kg; P<0.0001). Appreciable quantities of simple phenols (hydroxytyrosol and tyrosol) were detected in olive oils, with significant differences between extravirgin (41.87 +/- 6.17) and refined virgin olive oils (4.72 +/- 215; P<0.01). The major linked phenols were secoiridoids and lignans. Although extra virgin contained higher concentrations of secoiridoids (27.72 +/- 6.84) than refined olive oils (9.30 +/- 3.81) this difference was not significant. On the other hand, the concentration of lignans was significantly higher (P<0.001) in extra virgin (41.53 +/- 3.93) compared to refined virgin olive oils (7.29 +/- 2.56). All classes of phenolics were shown to be potent antioxidants. In future epidemiologic studies, both the nature and source of olive oil consumed should be differentiated in ascertaining cancer risk.

Antioxidants↗
PubMed1997

High level expression and characterization of recombinant human hippocampus phenol sulfotransferase: a novel phenol-sulfating form of phenol sulfotransferase.

Phenol sulfotransferases (PSTs) represent a family of sulfotransferase enzymes that modify the biologic activities and excretion of phenolic compounds and monoamines. A novel human hippocampal PST (H-PST) cDNA with homology to phenol (P) and monoamine (M) forms of PST was previously isolated from brain. To compare the biochemical properties of H-PST with that of phenol (P-PST) and monoamine (M-PST) sulfotransferases, high level expression of recombinant H-PST was achieved in this study with the pET3c vector in BL21(DE3) Escherichia coli cells. Expression was demonstrated by isopropyl beta-D-thiogalactopyranoside induction of 34-kDa H-PST that represented 5-10% of total E. coli proteins. Purification by ion-exchange chromatography on DEAE-Sepharose yielded more than 2 mg of H-PST. Characterization showed that H-PST exists as a homodimer of 60-65 kDa by gel filtration chromatography. H-PST prefers p-nitrophenol as substrate and does not sulfate dopamine or neuropeptide substrates. Kinetic studies showed that H-PST possessed K(m(app)) and Vmax(app) values of 3 microM p-nitrophenol and 160 nmol/min/mg, respectively. H-PST was sensitive to inhibition by DCNP (2,6-dichloro-4-nitrophenol). H-PST is thermolabile since its activity was reduced upon preincubation at 37 degrees C. These results indicate that H-PST shows similarities and differences compared to P-PST and M-PST sulfotransferases. P-PST prefers p-nitrophenol as substrate, is sensitive to inhibition by DCNP, and is thermostable; in contrast, M-PST prefers monoamines as substrate, is not sensitive to DCNP, and is thermolabile. The distinct profile of biochemical properties of H-PST, and its primary sequence homology to P-PST and M-PST, suggests that H-PST represents a novel allelic variant of human phenol sulfotransferases. Importantly, this study demonstrates that high level expression of H-PST allows determination of distinguishing characteristics of variant forms of PSTs.

Alleles↗
PubMed1975

[The phenolics of fruits. VI. The phenolics of currants, gooseberries and blueberries. Changes in phenolic acids and catechins during development of black currants (author's transl)].

Black, red, and white currants, gooseberries and cultivated blueberries contained only small amounts of catechins (total up to 30 mg per kg). Hydroxycinnamic acid derivatives, especially of caffeic and p-coumaric acid, occured mostly in higher concentrations. Furthermore, 4-hydroxygenzoic acid, protocatechuic acid and gallic acid were found after hydrolysis in currants and only protocatechuic acid in gooseberries in different levels. Salicyclic and gentisic acid were found in traces up to 2 mg per kg, occassionally vanillic acid, syringic acid or isoferulic acid. The concentrations of the examined phenolic acids in black currants related to the whole fruit (mg per fruit) increased, and related to fresh weight (mg per 1000 g) decreased during the growth of the fruits with the exception of protocatechuic acid, which appeared mostly in a last stage of the fruit.

Benzopyrans↗
PubMed1976

High-pressure liquid chromatographic separation of 10 benzo(a)pyrene phenols and the identification of 1-phenol and 7-phenol as new metabolites.

The separation of ten isomeric benzo(a)pyrene phenols has been accomplished by the use of high-pressure liquid chromatography utilizing a newly developed recycling technique and new column and solvent systems. Using this new system and comparing the metabolites obtained with authentic standards, we have isolated 1-hydroxybenzo(a)pyrene and 7-hydroxybenzo(a)pyrene and identified them as metabolites formed by rat liver microsomes. In previously reported chromatography systems, the new metabolites migrated with another metabolite, 3-hydroxybenzo(a)pyrene.

Animals↗
PubMed1985

Incorporation of phenol carbon at trace concentrations by phenol-mineralizing microorganisms in fresh water.

The fate of phenol carbon at phenol concentrations ranging from 1 ng/ml to 1 microgram/ml was determined in freshwater samples. Approximately 20% of the parent phenol was incorporated into trichloroacetic acid-precipitable material by the microorganisms capable of mineralizing phenol. There was no apparent lag period before phenol incorporation commenced, and incorporation was complete within 2 h at all concentrations tested. A direct relationship was found between the initial phenol concentrations and both phenol mineralization and incorporation rates, indicating that cometabolism of phenol does not occur at concentrations that are environmentally significant. At all concentrations, approximately 80% of the initial phenol concentration was mineralized. This percentage plus the percentage of phenol incorporated at the various concentrations equaled approximately 100%. Therefore, the parent phenol does not remain in fresh water; it is either incorporated into cellular biomass or mineralized. However, the incorporated phenol carbon is subject to bioaccumulation in nature. There was no apparent lag period before thymidine was incorporated into biomass, and incorporation was complete within 4 to 8 h at all of the phenol concentrations tested. Thymidine incorporation was independent of phenol concentration at all levels tested. This is probably due to the small amount of thymidine incorporated by the phenol-mineralizing microorganisms in comparison with the amount of thymidine incorporated by the total microbial population.

Bacteria↗
PubMed1982

The origin of urinary aromatic compounds excreted by ruminants. 3. The metabolism of phenolic compounds to simple phenols.

Dietary phenolic cinnamic acids are hydrogenated in the side-chain, demethylated and dehydroxylated in the rumen and are responsible for the large urinary output of benzoic acid by ruminants. 2. Decarboxylation of phenolic acids to simple phenols is another reaction of the intestinal microflora and experiments were made to determine the extent of this reaction in the rumen of sheep. 3. In five experiments phenolic compounds, quinic acid or casein were infused into the rumen or abomasum of sheep and increments in urinary outputs of phenolic acids and phenols determined by thin-layer and gas-liquid chromatography. 4. Production of phenols was almost exclusively confined to reactions in the rumen. 5. Rumen administration of phenolic benzoic or phenylacetic acids which contained a 4-hydroxy substituent yielded large increments in urinary phenol outputs. Other phenolic benzoic and phenylacetic acids were not decarboxylated. Rumen decarboxylation of 4-hydroxy-3-phenylpropionic acid did not occur and decarboxylation of 4-hydroxycinnamic acids was slight. 6. Nearly half the tyrosine content of rumen-administered casein was excreted as p-cresol, a decarboxylation product of 4-hydroxyphenylacetic acid, p-Cresol was the principal phenol found in sheep urine. 7. Catechol and phenol were consistently found in sheep urine samples and p-ethylphenol, resorcinol, quinol, 4-methylcatechol, orcinol and pyrogallol were also found when suitable precursors were infused to the rumen. 8. It is concluded that p-cresol is a rumen metabolite of tyrosine. The other phenols found are microbial metabolites of phenolic precursors which are either widely distributed in plants such as 4-hydroxybenzoic, protocatechuic and vanillic acids or of more limited distribution such as the orcinol glycosides of some Ericaceous plants.

Animals↗
PubMed1990

Effect of fluorinated analogues of phenol and hydroxybenzoates on the anaerobic transformation of phenol to benzoate.

The effects of fluorinated analogues on the anaerobic transformation of phenol to benzoate were examined. At greater than or equal to 250 microM 2- or 3-fluorophenol, phenol transformation was delayed. 2-Fluorophenol had no apparent effect on subsequent degradation of benzoate, but benzoate accumulated in the presence of greater than or equal to 250 microM 3-fluorophenol. In contrast, 4-fluorophenol at less than or equal to 2 mM had no effect on either phenol transformation or benzoate degradation. Phenol and 2-, or 3-fluorophenol were transformed simultaneously, but phenol was transformed more rapidly than either fluorophenol. Thus, fluorinated analogues of phenol did not prevent anaerobic transformation of phenol to benzoate. 2-Fluorophenol was converted to 3-fluorobenzoate, and phenol enhanced the rate and extent of its transformation. 3-Fluorophenol was transformed to 2-fluorobenzoate to a limited extent (approximately 3%) when phenol was present. 4-Fluorophenol was not transformed regardless of the presence of phenol. 3-Fluoro-4-hydroxybenzoate, a potential fluorinated intermediate product of para-carboxylation, was transformed rapidly to 2-fluorophenol and 3-fluorobenzoate, irrespective of the presence of phenol, indicating that both dehydroxylation and decarboxylation occurred. Initially, 2-fluorophenol and 3-fluorobenzoate were rapidly formed in an approximate molar ratio of 2:1. Once 3-fluoro-4-hydroxybenzoate was completely removed, the 2-fluorophenol, initially formed, was converted to 3-fluorobenzoate at a slower rate. Thus, phenol enhanced transformation of the fluorinated analogues, and the products of transformation suggested para-carboxylation. 3-Fluoro-2-hydroxybenzoate was not transformed in either the presence or absence of phenol, indicating that ortho-carboxylation did not occur.

Anaerobiosis↗
PubMed1994

Evidence that phenol phosphorylation to phenylphosphate is the first step in anaerobic phenol metabolism in a denitrifying Pseudomonas sp.

Anaerobic phenol degradation has been shown to proceed via carboxylation of phenol to 4-hydroxybenzoate. However, in vitro the carboxylating enzyme was inactive with phenol; only phenylphosphate (phosphoric acid monophenyl ester) was readily carboxylated. We demonstrate in a denitrifying Pseudomonas strain that phenylphosphate is the first detectable product formed from phenol in whole cells and that subsequent phenylphosphate consumption parallels 4-hydroxybenzoate formation. These kinetics are consistent with phosphorylation being the first step in anaerobic phenol degradation. Various cosubstrates failed so far to act as phosphoryl donor for net phosphorylation of phenol in cell extracts. Yet, cells anaerobically grown with phenol contained an enzyme that catalyzed an isotope exchange between [U-14C]phenol and phenylphosphate. This transphosphorylation activity was anaerobically induced by phenol but was stable under aerobic conditions and required Mn2+ and polyethylene glycol. Activity was optimal at pH 5.5 and half-maximal with 0.6 mM Mn2+, 0.2 mM phenylphosphate, and 1 mM phenol. It is proposed that the phenol exchange/transphosphorylation reaction is catalyzed as partial reaction by an inducible phenol phosphorylating enzyme. The isotope exchange demands that a phosphorylated enzyme was formed in the course of the reaction, which might be similar to the phosphotransferase system of sugar transport.

Anaerobiosis↗
PubMed1986

Lethal and sublethal effects of chlorine, phenol, and chlorine-phenol mixtures on the mud crab, Panopeus herbstii.

The mud crab, Panopeus herbstii, was acutely exposed (96-hr) to chlorine-produced oxidants (CPO), phenol, and a CPO-phenolic mixture (1:1) to determine lethal and sublethal effects. The 96-hr (LC50) values were determined for each individual compound and mixture. Additionally, whole-animal respiration rates were measured following acute exposure to sublethal concentrations of each compound or mixture. Phenol uptake/depuration rates were measured in the phenol and CPO-phenol mixture concentrations. Results indicated 96-hr LC50 values of 1.06 mg/L for CPO (fiducial limits (FL) = 0.53-2.01 mg/L), 52.8 mg/L for phenol (FL = 45.6-64.5 mg/L), and 184.7 mg/L total toxicant units (TTU) for the CPO-phenol mixture (FL = 143.7-250.2 mg/L TTU). Statistical analysis indicated that the acute toxicity of the CPO-phenol mixture was less than additive. Sublethal studies indicated that only acute exposure to sublethal concentrations of CPO caused altered respiration rates. After 96-hr depuration, metabolic rates in all CPO-exposure crabs generally returned to control rates. Uptake/depuration rate studies indicated significantly lower phenol uptake rates in crabs exposed to the CPO-phenol mixture. These findings suggest that the less-than-additive toxicity of the CPO-phenol mixture may result from lowered uptake/depuration rate kinetics and indicate that the discharge of chlorinated-phenolic waste may not result in additive and/or synergistic interactions, but rather in less-than-additive effects on decapod aquatic species.

Animals↗
PubMed1998

The crystal structure of phenol hydroxylase in complex with FAD and phenol provides evidence for a concerted conformational change in the enzyme and its cofactor during catalysis.

BACKGROUND: The synthesis of phenolic compounds as by-products of industrial reactions poses a serious threat to the environment. Understanding the enzymatic reactions involved in the degradation and detoxification of these compounds is therefore of much interest. Soil-living yeasts use flavin adenine dinucleotide (FAD)-containing enzymes to hydroxylate phenols. This reaction initiates a metabolic sequence permitting utilisation of the aromatic compound as a source of carbon and energy. The phenol hydroxylase from Trichosporon cutaneum hydroxylates phenol to catechol. Phenol is the best substrate, but the enzyme also accepts simple hydroxyl-, amino-, halogen- or methyl-substituted phenols. RESULTS: The crystal structure of phenol hydroxylase in complex with FAD and phenol has been determined at 2.4 A resolution. The structure was solved by the MIRAS method. The protein model consists of two homodimers. The subunit consists of three domains, the first of which contains a beta sheet that binds FAD with a typical beta alpha beta nucleotide-binding motif and also a fingerprint motif for NADPH binding. The active site is located at the interface between the first and second domains; the second domain also binds the phenolic substrate. The third domain contains a thioredoxin-like fold and is involved in dimer contacts. The subunits within the dimer show substantial differences in structure and in FAD conformation. This conformational flexibility allows the substrate to gain access to the active site and excludes solvent during the hydroxylation reaction. CONCLUSIONS: Two of the domains of phenol hydroxylase are similar in structure to p-hydroxybenzoate hydroxylase. Thus, phenol hydroxylase is a member of a family of flavin-containing aromatic hydroxylases that share the same overall fold, in spite of large differences in amino acid sequences and chain length. The structure of phenol hydroxylase is consistent with a hydroxyl transfer mechanism via a peroxo-FAD intermediate. We propose that a movement of FAD takes place in concert with a large conformational change of residues 170-210 during catalysis.

Amino Acid Sequence↗
PubMed2003

Effects of phenol-depleted and phenol-rich diets on blood markers of oxidative stress, and urinary excretion of quercetin and kaempferol in healthy volunteers.

OBJECTIVE: Epidemiological studies have suggested beneficial effects of dietary polyphenols in reducing the risk of chronic diseases. This study was performed to investigate the effects of polyphenol-depleted and polyphenol-rich diets on blood oxidative stress markers and urinary excretions of major phenols. METHODS: Nineteen healthy female non-smokers 19 to 21 years of age took part in the study, which consisted of two dietary intervention periods separated by three days. Experimental diets were composed of common foods selected to comply with low contents of polyphenols for phenol-depleted intervention and high contents of polyphenols for phenol-rich diets. Blood and urine samples were collected on day 0, 3 and 6 of each intervention. Duplicate portions of foods provided to the subjects were also collected. Blood oxidative stress markers included plasma antioxidant vitamins, erythrocyte superoxide dismutase (SOD) activity and lymphocyte DNA damage. Urinary excretions of major phenols were measured to affirm bioavailability of dietary phenols. RESULTS: Plasma alpha-tocopherol and beta-carotene concentrations were slightly decreased on day 3 and 6 of the phenol-depleted dietary intervention period, although no change was observed with phenol-rich diets. The erythrocyte SOD activity was also slightly decreased during phenol-depleted dietary intervention. However, at day 6 of the phenol-rich intervention, the activity of SOD was significantly increased by 41%. Tail moment and tail length of lymphocyte DNA as markers of DNA damage were higher on day 6 of phenol-depleted intervention, although only tail moment showed a statistical significance. The average intakes of quercetin and kaempferol during the phenol-rich intervention were 21 mg/day and 9 mg/day, respectively. The average urinary excretion rates during phenol-rich intervention were 2.06% for quercetin and 0.46% for kaempferol. There were positive correlations between erythrocyte SOD activity and urinary concentration of quercetin or kaempferol. CONCLUSIONS: These results suggest that polyphenol-rich diets may decrease the risk of chronic diseases by reducing oxidative stress.

Adult↗
PubMed2002

Kinetics of phenol oxidation by Candida tropicalis: effects of oxygen supply rate and nutrients on phenol inhibition.

The kinetics of phenol degradation was estimated in a fed-batch reactor system. Effects of oxygen and nutrient excess or limitation as well as the presence of several essential ions on the phenol- and oxygen-specific uptake rates achieved simultaneously in a bioreactor were shown. Candida tropicalis was grown on phenol as the only carbon and energy source. Applying the best fit of polynomial function, the maximum specific uptake rates of phenol and oxygen, the critical concentrations of phenol, the half-saturation constants and inhibition constants were determined. Linear relationship between specific phenol uptake rate and the exogenous respiration rate was found regardless of the kind and presence of essential nutrients. At oxygen limitation both the phenol uptake rate and the cell affinity to phenol decreased more strongly compared with those under nutrient limitation. Oxygen in excess resulted in a significant increase of cell tolerance toward phenol. The presence of essential nutrients increased the specific phenol degradation rate and led to complete phenol oxidation.

Biodegradation, Environmental↗
PubMed1972

Renal handling of phenol red. I. A comparative study on the accumulation of phenol red and p-aminohippurate in rabbit kidney tubules in vitro.

1. The characteristics of renal accumulation of phenol red and p-aminohippurate (PAH) by slices of rabbit kidney cortex suspended in an electrolyte medium have been compared.2. It has been found that at low medium concentrations the accumulation of phenol red is about 4-5 times as high as that of PAH. Furthermore, phenol red is accumulated by the renal tissue under anaerobic conditions, in contrast to PAH.3. Experiments involving incubation of slices at low temperatures and addition of various metabolic inhibitors to the medium, indicate that the anaerobic accumulation of phenol red is due to binding to cellular constituents. This conclusion is corroborated by studies on renal homogenates from which it appears that phenol red is bound predominantly to the microsomal and mitochondrial fraction.4. The aerobic accumulation of phenol red is less susceptible to inhibition by probenecid, 2,4-dinitrophenol (DNP), and octanoate than is that of PAH. Besides, probenecid, DNP, and octanoate inhibit phenol red binding to the microsomal fraction, whereas mitochondrial binding of phenol red is unaffected by the presence of these substances.5. Fumarate and succinate affect the aerobic accumulation of phenol red and PAH to the same degree. Furthermore, fumarate, succinate, and PAH do not alter anaerobic accumulation of phenol red.6. It is concluded that probenecid, DNP, and octanoate cause more inhibition of organic anion transport than fumarate, succinate, and PAH because of lipophilic interaction with the membrane. The pronounced resistance of phenol red accumulation to inhibition by lipophilic inhibitors is probably due to the ability of the indicator dye to displace these substances from binding sites on the transporting membranes.

Aerobiosis↗