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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↗

PubMed2003

Inhibition of the acetoclastic methanogenic activity by phenol and alkyl phenols.

Chemical and petrochemical industries are important sources of aromatic pollutants. Petrochemical processes like caustic washing of middle distillates produce the spent caustic liquors highly concentrated in phenol and alkyl phenols. The anaerobic technology is considered a feasible strategy for petrochemical wastewater pre-treatment although high concentrations of phenol could limit its efficiency. The goal of this work was to determine the toxicity of both selected alkyl phenols and a synthetic "spent-caustic phenols mixture" on the acetoclastic Specific Methanogenic Activity (SMA) of unadapted and phenol-adapted granular sludge. Alkyl phenols were responsible for 50% (IC50) and 100% (IC100) inhibition of the SMA at concentrations ranging from 1.6 to 5.0 mM and from 4.1 to 27.5 mM, respectively, for un-adapted granular sludge. In the case of phenol-adapted granular sludge, the inhibitory concentrations ranged from 1.7 to 14.9 mM and from 4.0 to 83.0 for IC50 and IC100, respectively, highlighting the impact of sludge acclimation. The inhibition produced by 2-ethylphenol was more acute compared to phenol and was not reduced by the phenol acclimation process. The IC50 and IC100 values obtained for the synthetic "spent-caustic phenols mixture" were 9.5 mM and 88.4 mM, respectively. The inhibitory concentrations of phenol compounds were closely correlated with compound apolarity (log P), indicating that the lipophilic character of the tested compounds was responsible for their methanogenic toxicity. An inhibition model is confirmed to estimate the IC50 and IC100.

Bacteria, Anaerobic↗

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↗

PubMed2005

Postprandial LDL phenolic content and LDL oxidation are modulated by olive oil phenolic compounds in humans.

Olive oil phenolic compounds are potent antioxidants in vitro, but evidence for antioxidant action in vivo is controversial. We examined the role of the phenolic compounds from olive oil on postprandial oxidative stress and LDL antioxidant content. Oral fat loads of 40 mL of similar olive oils, but with high (366 mg/kg), moderate (164 mg/kg), and low (2.7 mg/kg) phenolic content, were administered to 12 healthy male volunteers in a cross-over study design after a washout period in which a strict antioxidant diet was followed. Tyrosol and hydroxytyrosol, phenolic compounds of olive oil, were dose-dependently absorbed (p<0.001). Total phenolic compounds in LDL increased at postprandial state in a direct relationship with the phenolic compounds content of the olive oil ingested (p<0.05). Plasma concentrations of tyrosol, hydroxytyrosol, and 3-O-methyl-hydroxytyrosol directly correlated with changes in the total phenolic compounds content of the LDL after the high phenolic compounds content olive oil ingestion. A 40 mL dose of olive oil promoted a postprandial oxidative stress, the degree of LDL oxidation being lower as the phenolic content of the olive oil administered increases. In conclusion, olive oil phenolic content seems to modulate the LDL phenolic content and the postprandial oxidative stress promoted by 40 mL olive oil ingestion in humans.

Adult↗

PubMed2004

Characterization of hydrated Na+(phenol) and K+(phenol) complexes using infrared spectroscopy.

Hydrated alkali metal ion-phenol complexes were studied to model these species in aqueous solution for M=Na and K. IR predissociation spectroscopy in the O-H stretch region was used to analyze the structures of M+(Phenol)(H2O)n cluster ions, for n = 1-4. The onset of hydrogen bonding was observed to occur at n=4. Ab initio calculations were used to qualitatively explore the types of hydrogen-bonded structures of the M+(Phenol)(H2O)4 isomers. By combining the ab initio calculations and IR spectra, several different structures were identified for each metal ion. In contrast to benzene, detailed in a previous study of Na+(Benzene)n(H2O)m [J. Chem. Phys. 110, 8429 (1999)], phenol is able to bind directly to Na+ even in the presence of four waters. This is likely the result of the sigma-type interaction between the phenol oxygen and the ion. With K+, the dominant isomers are those in which the phenol O-H group is involved in a hydrogen bond with the water molecules, while with Na+, the dominant isomers are those in which the phenol O-H group is free and the water molecules are hydrogen-bonded to each other. Spectra and ab initio calculations for the M+(Phenol)Ar cluster ions for M=Na and K are reported to characterize the free phenol O-H stretch in the M+(Phenol) complex. While pi-type configurations were observed for binary M+(Phenol) complexes, sigma-type configurations appear to dominate the hydrated cluster ions.

Journal Article↗

PubMed2005

Isolation and identification of novel high strength phenol degrading bacterial strains from phenol-formaldehyde resin manufacturing industrial wastewater.

Phenols are toxic to all types of organisms. Two bacterial strains capable of utilizing phenol as a sole carbon source were isolated from the phenol bearing industrial wastewater. Based on the biochemical test results the organisms were identified as Pseudomonas cepacia and Bacillus brevis. The organisms were very efficient in phenol degradation, the lag phase increased with increase in phenol concentration. The well-acclimatized cultures of P. cepacia and B. brevis degraded 2500 and 1750 mg l(-1) of phenol in 144 h, respectively. The organisms degrade phenol even in the presence of toxicants like thiocyanate, sulphide and cyanide. The organisms can be effectively used for treating high strength phenol containing thiocyanate, sulphide and cyanide. The P. cepacia degrades phenol with a faster rate than B. brevis. P. cepacia can be used effectively for treating high strength phenolic wastewater.

Biodegradation, Environmental↗

PubMed2005

Kinetics of the oxidation of phenols and phenolic endocrine disruptors during water treatment with ferrate (Fe(VI)).

The ability of ferrate (Fe(VI)) to oxidize phenolic endocrine-disrupting chemicals (EDCs) and phenols during water treatment was examined by determining the apparent second-order rate constants (k(app0) for the reaction of Fe(VI) with selected environmentally relevant phenolic EDCs (17alpha-ethinylestradiol, beta-estradiol, and bisphenol A) and 10 substituted phenols at pH values ranging from 6 to 11. The three selected groups of EDCs showed appreciable reactivity with Fe(VI) (kapp at pH 7 ranged from 6.4 x 102 to 7.7 x 10(2) M(-1) s(-1)). The k(app) for the substituted phenols studied at pH 7 ranged from 6.6 to 3.6 x 10(3) M(-1) s(-1), indicating that many other potential phenolic EDCs can be oxidized by Fe(VI) during water treatment. The Hammett-type correlations were determined for the reaction between HFeO4- and the undissociated (log(k) = 2.24-2.27sigma+) and dissociated phenol (log(k) = 4.33-3.60sigma+). A comparison of the Hammett correlation obtained for the reaction between HFeO4- and dissociated phenol with those obtained from other drinking water oxidants revealed that HFeO4- is a relatively mild oxidant of phenolic compounds. The effectiveness of Fe(VI) for the oxidative removal of phenolic EDCs was also confirmed in both natural water and wastewater.

Endocrine Disruptors↗

PubMed2001

Efficacy of topical phenol decontamination strategies on severity of acute phenol chemical burns and dermal absorption: in vitro and in vivo studies in pig skin.

Pure phenol is colorless and used in the manufacture of phenolic resins, plastics, explosives, fertilizers, paints, rubber, textiles, adhesives, pharmaceuticals, paper, soap, and wood preservatives. The purpose of this study was to compare the efficacy of several phenol decontamination strategies following dermal exposure using the pig as a model for human exposure, and then assess the effect of the two best treatments on phenol absorption in the isolated perfused porcine skin flap (IPPSF). Six anesthetized Yorkshire pigs were exposed to 89% aqueous phenol for 1 min using Hilltop chambers (10 skin sites/pig; 400 microl/site). Exposure to phenol was followed by one of 10 different decontamination procedures: 1-, 5-, 15-, and 30-min water wash; Ivory soap solution; polyethylene glycol (PEG 400); PEG 400/industrial methylated spirits (IMS); PEG 400/ethanol (EtOH); polyvinyl pyrrolidone (PVP)/70% isopropanol (IPA); and 70% IPA. For each of the last five strategies, 1-min treatment washes were repeatedly alternated with 1-min water washes for a total of 15 min. Evaluation was based on scoring of erythema, edema, and histological parameters such as intracellular and intercellular epidermal edema, papillary dermal edema, perivascular infiltrates, pyknotic stratum basale cells, and epidermal-dermal separation. It was concluded that PEG 400 and 70% IPA were superior to the other treatments investigated and equally efficacious in the reduction of phenol-induced skin damage. In addition, phenol absorption was assessed utilizing the two most effective in vivo treatments in the IPPSF. The assessment of percutaneous absorption of phenol found the PEG 400, 70% IPA, and 15-min water treatments significantly (P < 0.05) reduced phenol absorption relative to no treatment.

Absorption↗

PubMed1998

Adaptation of Comamonas testosteroni TA441 to utilize phenol: organization and regulation of the genes involved in phenol degradation.

Comamonas testosteroni TA441 was not able to grow on phenol as a sole carbon and energy source, but it gained the ability to utilize phenol after a 2-3-week incubation in a medium containing phenol. Phenol hydroxylase (PH) and catechol 2,3-dioxygenase (C230) were highly induced by phenol in the adapted strain designated as strain P1, suggesting that phenol was degraded via the meta-pathway. Gene clusters for phenol degradation were isolated from both strains TA441 and P1. The structural genes encoding multi-component PH and C230 (aphKLMNOPQB), and a regulatory gene of the NtrC family (aphR), were located in a divergent transcriptional organization. The cloned aphKLMNOPQB genes from either strain TA441 or strain P1 produced active PH and C230 enzymes in strain TA441. No difference was found between the strains in the sequences of aphR and the intergenic promoter region of aphK and aphR. However, the transcriptional activities of the aphK and aphR promoters were higher in strain P1 than in strain TA441. The aphK-promoter activity was not observed in aphR mutant strains and these strains could not grow on phenol. The aphR mutant of strain P1 was able to grow on phenol after transformation with a recombinant aphR gene but strain TA441 was not, suggesting that the expression of the aph genes is silenced by an unidentified repressor in strain TA441 and that this repressor is modified in strain P1.

Base Sequence↗

PubMed1992

Prostaglandin H synthase kinetics. The effect of substituted phenols on cyclooxygenase activity and the substituent effect on phenolic peroxidatic activity.

A series of p- and m-substituted phenols were examined for their effect on the cyclooxygenase activity of prostaglandin H synthase in 0.1 M phosphate buffer at pH 8.0 and 25.0 +/- 0.1 degrees C. A biphasic response was observed. At low concentrations phenols stimulate, but at higher concentrations inhibit, cyclooxygenase activity. Both enhancement and inhibition are increased by phenolic substituents which are electron-donating, quantified by Hammett sigma constants, and hydrophobic, quantified by Hantsch tau constants. The same series of substituted phenols was also reacted with compound II of prostaglandin H synthase at 4.0 +/- 0.5 degrees C. The compound II data fit the Hammett rho sigma equation; no hydrophobicity factors are required. Phenols inhibit cyclooxygenase activity by interfering with the binding of arachidonic acid to compound I and by competing directly with arachidonic acid as reducing substrates for compound I. Phenols stimulate cyclooxygenase activity by acting as reducing substrates for compound II, thereby accelerating the peroxidatic cycle. Phenols also protect the enzyme from self-catalyzed inactivation, most likely by removing the free radical of prostaglandin G2 by reducing it to prostaglandin G2. Kinetic parameters Km and kcat for cyclooxygenase activity were determined in the presence of phenols. Identical values of Km (15.3 +/- 0.5 mM) and kcat (89 +/- 2 s-1) were obtained regardless of which phenol was employed. Therefore these represent the true Km and kcat values for cyclooxygenase activity.

Animals↗

PubMedDate not supplied

Chemical derivatization analysis of pesticide residues. IX. Analysis of phenol and 21 chlorinated phenols in natural waters by formation of pentafluorobenzyl ether derivatives.

A sensitive, isomer-specific method is described for the simultaneous and quantitative analysis of 22 phenols (phenol, 18 chlorophenols, and 3 chloroalkylphenols) in natural waters. The sample was acidified to pH less than or equal to 2, extracted with dichloromethane, evaporated, and dissolved in acetone. The phenol extract was then reacted with pentafluorobenzyl bromide (PFBBr) to give the PFB ether derivatives. After silica gel column cleanup, the ethers were chromatographed on a 12 m OV-1 fused silica capillary column attached to an electron capture detector (ECD). The detection limit was 0.1 ppb for 1 L samples. Recoveries of phenols from pH 2 water samples fortified at 10, 1, and 0.1 ppb were greater than or equal to 80% in most cases except for phenol which was only 30 to 35% recovered. Coefficients of variation were between 2 and 10% for all phenols. However, phenol recovery was quantitative when the sample volume was reduced to 100 mL. Because ECD sensitivities to the 22 phenol PFB ethers were similar, this method is most suitable for simultaneous screening of nonchlorinated and monochlorinated phenols as well as other higher chlorophenols at trace levels.

Chlorophenols↗

PubMed1957