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PubMed2026

Nutrikinetics and bioavailability of Promunel®, a standardized poplar-type propolis phenolic extract: a double-blinded, placebo-controlled, cross-over, randomized trial.

Brown poplar-type propolis has been recognized and used for centuries to help prevent upper respiratory tract infections (URTIs). However, the scarce, incomplete information in humans on the nutrikinetics and bioavailability of its phenolic constituents, combined with a lack of standardization in its phenolic content and profile pose major challenges to develop bioactive ingredients. Thus, the aim of this study was to establish the nutrikinetics and total bioavailability (NKBA) parameters of brown poplar-type propolis phenolics in humans using the Standardized Propolis Extract (SPE) Promunel®. To achieve this, a 48 h NBKA study was conducted following a double blinded, randomized, placebo-controlled, cross-over design in healthy humans (n = 10) with two doses of SPE (1X = 400 mg or 4X = 1600 mg). Phenolic compounds were detected, identified and quantified in the extract, plasma and urine through different LC-MS/UV technologies. The SPE used is a rich (304.44 ± 15.61 µmol mg-1) and diverse source of phenolic compounds (5 sub-families). A total of 63 and 85 phenolic metabolites were identified and quantified in plasma and urine, mostly in the form of glucuronides and sulfates. In plasma, phenolic metabolites reached Cmax (1.22 ± 0.20 for 1X and 4.80 ± 0.48 µM for 4X) after 1 h of SPE intake, while urinary excretion occurred mostly during the first 3 h after. The total net bioavailability of SPE phenolic compounds at 48 h was 57.16 ± 5.71% for 1X and 43.82 ± 6.77% for 4X. Generally, the data between SPE 1X and 4X were proportional, indicating that a higher dose does not substantially modulate total net bioavailability. Overall, our data shows that brown poplar-type SPE phenolic compounds are highly bioavailable in the form of cinnamic acid and flavonoid conjugates, and that these compounds are rapidly absorbed and eliminated through the urine. Our results suggest that, for a sustained presence in circulation, brown poplar-type propolis supplements should be consumed more than once a day.

Humans↗
PubMed1978

Design of a specific oxidant for phenols.

Selective ortho-substitution of phenols can be secured, in principle, by attachment of the substituting reagent to the phenolic hydroxy group and subsequent rearrangement of this derivative by a cyclic mechanism into the orthoposition. So far, only one example of this principle (the Claisen rearrangement) is well established. For ortho-hydroxylation, a phenolic ester of selenium(IV) should have the desired properties. Diphenylseleninic anhydride, PhSE(=0)0.Sec(=0)Ph, has proved has proved to be the new reagent for the application of this mechanism. Several phenols, including models of the phenolic ring A of tetracycline, gave o-hydroxydienones, with quinones and phenylselenated species as by-products, when treated with diphenylseleninic anhydride. When the phenols were converted into their corresponding anions before treatment with the anhydridide, the o-hydroxydienones were obtained in good yield free from other products arising from reaction at the para position. When phenols were added to a warm solution of diphenylseleninic anhydride, they were oxidized to the o-quinones even when the phenols were not substituted in para position.

Anhydrides↗
PubMed1978

Pyridine interactions with phenolic groups in water: evidence for hydrogen bonding and hydrophobic association.

Pyridine interactions with phenol, substituted phenol, tyrosine and poly(Glu50,Tyr50) in aqueous solutions have been studied by ultraviolet (UV) difference spectroscopy, spectrophotometric pH titration, circular dichroism (CD) and proton magnetic resonance (PMR) spectroscopy. A red shift and spectral sharpening of the near-UV spectrum of phenol in water was noted at pyridine concentrations greater than 0.25 M. In addition, the spectrophotometric equivalence point for the phenol- or substituted phenol-phenolate equilibrium was increased about 0.5 pH units upon the addition of 1.0 M pyridine. PMR studies were consistent with the formation of a 1 : 1 phenol-pyridine hydrogen bonded complex. The equilibrium constant derived for this interaction, 0.6-0.7 M-1, is greater than the corresponding value for phenol-acetate hydrogen bonding in water. Enhancement of thepyridine hydrogen bond interaction with Tyr within poly(Glu50,Tyr50) was observed at pH greater than 12 due to a hydrophobic microenvironment produced by pyridine molecules intercalating between neighboring tyrosyl residues.

Circular Dichroism↗
PubMed2026

QTLs associated with phenolic acid accumulation and antioxidant activity in tropical maize.

Maize represents a significant source of phytochemicals, with phenolic acids standing out as one of the most extensively studied functional compound families. These bioactive molecules have gained attention for their potent antioxidant properties and potential contributions to human health improvement. To evaluate the segregation of phenolic compounds in maize and its genetic basis, this study was conducted to identify quantitative trait loci (QTLs) associated with major phenolic compounds and their antioxidant capacity. The mapping population comprised 100 recombinant inbred lines (RILs) derived from the cross between P84 and Kilima. Twelve traits were analyzed: free and cell wall-bound antioxidant capacity, total phenolic content, and contents of p-coumaric acid, ferulic acid, three isomers of di-ferulic acid, and three isomers of tri-ferulic acid. The RILs exhibited substantial diversity in phenolic compound profiles. In total, 19 QTLs were identified for nine traits, with the number of associated regions ranging from 1 to 5 and explaining between 2.95% and 37.48% of the phenotypic variation. This research provides substantial evidence for the co-localization of major QTLs for principal phenolic acids in maize with genomic regions harboring genes putatively related to their biosynthesis and biotic resistance. This is the first study to report QTLs associated with triferulic acids in maize. The identified regions co-localizing with biotic stress resistance genes represent targets for marker-assisted selection toward the improvement of phenolic acid accumulation in maize breeding programs.

QTLs↗
PubMed1978

[The influence on efficacy of formaldehyd and phenol against bacterial cells I. Effect of drying, cations and pH-value (author's transl)].

1. When cells of E. coli and Staph. aureus are dried, the efficacy of phenol is reduced but the efficacy of formaldehyde is increased. 2. A change of the aw-value by addition of salts changes the efficacy of formaldehyde as well as that of phenol. For these tests the chlorides of various alkali and alkaline earth metals were used in different concentrations. 3. The optimal efficacy of phenol and formaldehyde within the tested concentration gradientis caused by different concentrations of the ions: In low concentrations the efficacy of formaldehyde is optimally increased, the efficacy of phenol, however, attains a minimum at this concentration range. By higher concentrations of ions the efficacy of phenol is increased, that of formaldehyde is reduced. 4. The position of the cations in the periodic system also plays a role in the influence on the efficacy of the phenol and formaldehyde respectively. The cations of the lower periods from the main groups I and II favour the damage to the cells by phenol, the cations of the higher periods favour the damage by formaldehyde.

Bacteria↗
PubMedDate not supplied

[Volatile phenolic compounds in white wines].

By gas-liquid chromatography the following volatile phenols were identified in extracts and distillates of white table wines prepared with the aid of husks and pulp used in fermentation: phenol, m-cresol, guaicol, ethyl-4-phenol, vinyl-4-phenol, eugenol, tyrosol; phenol, m-cresol, guaicol, ethyl-4-phenol, vinyl-4-phenol. The amount of volatile oils grew significantly with an increase in the number of husks in the fermenting liquid and fermentation temperature.

Chromatography, Gas↗
PubMed1976

Comparison of uptake and binding of disodium cromoglycate and phenol red in rat lung.

In rat lung slices 3H-disodium cromoglycate (3H-DSCG) (0.001 mM) was taken up rapidly and 3H-DSCG tissue spaces, which equilibrated by 30 minutes, remained constant over a 4-hour incubation period. In contrast, 35S-phenol red (0.001 mM) accumulated in lung slices to a much greater extent than did DSCG, and the measured tissue spaces continued to increase over a 3-hour incubation period. In the presence of either phenol red (1 mM) or the metabolic inhibitors, iodoacetic acid (10(-4) M) and dinitrophenol (10(-4) M), 3H-DSCG uptake was significantly decreased. Accumulation of 3H-DSCG in lung slices and binding to tissue homogenates (pH 7.4) was also decreased when Ca and Mg ions were omitted from the bathing solution. Although DSCG and phenol red mutually inhibited the accumulation of one another over time in lung slices and 3H-DSCG (0.001 mM) binding to lung homogenates was decreased in the presence of 1 mM phenol red, 35S-phenol red efflux was not altered by the addition of 1 mM DSCG during the washout. Thus, it appears that, in rat lung, DSCG and phenol red share a common binding site(s) for uptake, possible on the transport "carrier." Also, there appear to be additional pulmonary binding sites for phenol red. These sites are not occupied by DSCG and their presence could account for the differences observed in the extent of accumulation of the two compounds in lung slices.

Animals↗
PubMed1977

Isolation of A-T-rich fragments from calf thymus DNA using the phenol method.

The action of phenol on the products of partial digestion of calf thymus DNA by K2 DNAase causes a loss of 3--5% of the material passing into the phenol phase. This part of DNA can be regained in the aqueous phase by lowering both the temperature and the ionic strength. Among oligonucleotides up to 7 monomers in length, those which are soluble in phenol do not contain guanine residues. Phenol-soluble DNA fragments of the molecular weight of an order of 2000--50,000 appeared to be composed mainly of adenosine phosphate. They also contain some thymine and only traces of guanine and cytosine. Some longer A-T-rich fragments, even up to 5-10(6) daltons, were repeatedly found in the phenol phase, but their base composition has not been determined yet. The method presented here was found very convenient for the isolation of relatively large A-T-rich DNA fragments. The property of DNA or its fragments to dissolve in phenol seems to be dependent on an adequate primary structure, probably similar to that of poly (dA-dT).

Animals↗
PubMed2026

Effects of apple phenolics on the human metabolome: modulation of key metabolic pathways.

Apples are widely recognized for their potential health benefits, partly attributed to their phenolic compounds. However, their impact on human metabolism remains incompletely understood. This study investigated metabolic effects of apple-derived phenolic compounds using untargeted metabolomics approach across multiple biofluids. In a crossover intervention study, 30 healthy men consumed a phenolic-rich apple juice or a placebo for two weeks. Blood, urine and saliva samples were collected before and after each intervention and analyzed by direct infusion ultra-high resolution mass spectrometry. Consumption of apple phenolic compounds resulted in significant alterations of the human metabolome, including increased levels of phenolic-derived degradation products and microbial-associated metabolites across all biofluids. Pathway enrichment analysis revealed pronounced effects on phenylalanine and tyrosine metabolism, as well as linoleic and arachidonic acid metabolism, Overall, these findings demonstrate that apple phenolic compounds induce measurable, microbiota-associated and systemic metabolic changes, providing new insights into their metabolic fate and biological relevance.

Humans↗
PubMed1979

In-vitro assessment of the removal of phenols by ACAC hemoperfusion.

The in-vitro removal of free phenols by means of perfusion over albumin coated cellulose nitrate microencapsulated activated charcoal (ACAC) was studied. The phenols tested were in the form of a standard solution comprised of phenol, p-cresol, and p-hydroxyphenylacetic acid in a ratio of 1:5:14. Four different activated charcoals were tested for their adsorption capacity. Further studies were conducted to determine; the effect of microencapsulation and albumin coating of the activated charcoal on the adsorption of phenols; the adsorption isotherm of phenols; the capacity; and the clearance values. The results obtained suggest that ACAC used in the management of patients with uremia or hepatic coma is extremely efficient in removing phenols in aqueous solution in the in-vitro situation.

Adsorption↗
PubMed1977

Effect of fuel composition on the emission of phenols in the exhaust gas from a European car.

The emission of phenols from a European car working with leaded and unleaded fuels with different percentage of aromatics has been considered. Fuels having the same aromatic content, but with a different composition of aromatic fraction, have also been taken into account. The results obtained showed that the emission of phenols increases with the increase of the aromatic content of fuel and also when unleaded instead of leaded fuels are used. The type of aromatic present in fuels was found to be important in forming the amount of both total and individual phenols emitted in the exhaust gas and in determining the number of phenolic compounds formed during combustion, although the phenol and isomer cresols were produced by combustion of all the fuels tested. The quantitative determination of individual phenols has been carried out on the benzene extract of the aqueous condensate and of the particulate matter of exhaust gas by the NaOH-extraction-GC-chromatographic method.

Cresols↗
PubMed1978

Renal handling of phenol red. III. Bidirectional transport.

1. The renal excretion of phenol red and other phenolsulphophthalein dyes (bromophenol blue and bromothymol blue) was studied in clearance experiments on anaesthetized rabbits. 2. Net tubular excretion of phenol red reached a maximal value of 8 mumole/min at a plasma concentration of ultrafiltrable dye of about 0.1 mM and was decreased at higher plasma concentrations. Decreases in net tubular excretion at high plasma concentrations were also obtained for bromophenol blue and bromothymol blue suggesting tubular reabsorption in addition to tubular secretion of the dye. Conclusive evidence for reabsorption was provided by administration of probenecid which caused a fall in the excretion of the dyes below that filtered by the glomeruli. 3. Tubular reabsorption of phenol red during probenecid administration appeared to be proportional to the glomerular load and was increased under experimental conditions leading to a decrease of urinary pH. Experiments involving efflux of phenol red from liposomes gave no evidence of a significant role of transmembrane passage by non-ionic diffusion. It is suggested that the pH dependence of the reabsorptive process is the result of preferential reabsorption of the acid as compared to the basic form of the indicator dye across a hydrophilic pathway in the transporting membranes. 4. Clearance ratio of phenol red to that of p-aminohippurate at low plasma concentrations was about 0.3. They low degree of extraction of phenol red from renal plasma is attributed both to tubular reabsorption and binding of the dye by plasma proteins.

Absorption↗
PubMed1976

The production of urinary phenols by gut bacteria and their possible role in the causation of large bowel cancer.

Epidemiological evidence is presented to relate the amount of dietary meat to the risk of large bowel cancer; it has been suggested that this may be due to the production of cocarcinogenic volatile phenols by intestinal bacteria from tyrosine. This paper describes preliminary experiments to test this suggestion. In vitro, aerobic bacteria tended to produce phenol from tyrosine while anaerobic bacteria produced p-cresol. Urine from 10 normal healthy persons contained a mean of 9.8 mg phenol/day and 51.8 mg p-cresol/day. Results from studies on patients with ileostomy, colostomy, and diverticular disease indicated that p-cresol is largely produced by the anaerobic flora of the left colon while phenol was produced in the ileum (when colonized) and cecum. In patients with familial polyposis the activity of the aerobic flora was apparently normal but there was greatly reduced amounts of p-cresol produced. The amounts of urinary volatile phenols in six patients with newly diagnosed large bowel cancer were not different from the normal values, indicating that cocarcinogenic phenols were unlikely to be a major cause of the disease.

Adult↗
PubMed1979

Metabolism of phenol and resorcinol in Trichosporon cutaneum.

Trichosporon cutaneum was grown with phenol or resorcinol as the carbon source. The formation of beta-ketoadipate from phenol, catechol, and resorcinol was shown by a manometric method using antipyrine and also by its isolation and crystallization. Metabolism of phenol begins with o-hydroxylation. This is followed by ortho-ring fission, lactonization to muconolactone, and delactonization to beta-ketoadipate. No meta-ring fission could be demonstrated. Metabolism of resorcinol begins with o-hydroxylation to 1,2,4-benzenetriol, which undergoes ortho-ring fission yielding maleylacetate. Isolating this product leads to its decarboxylation and isomerization to trans-acetylacrylic acid. Maleylacetate is reduced by crude extracts to beta-ketoadipate with either reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate as a cosubstrate. The enzyme catalyzing this reaction was separated from catechol 1,2-oxygenase, phenol hydroxylase, and muconate lactonizing enzyme on a diethyl-aminoethyl-Sephadex A50 column. As a result it was purified some 50-fold, as was the muconate-lactonizing enzyme. Methyl-, fluoro-, and chlorophenols are converted to a varying extent by crude extracts and by purified enzymes. None of these derivatives is converted to maleylacetate, beta-ketoadipate, or their derivatives. Cells grown on resorcinol contain enzymes that participate in the degradation of phenol and vice versa.

Adipates↗
PubMed1978

Phenols: a review of their history and development as antimicrobial agents.

Phenols were first isolated in crude form at the end of the eighteenth century. Pure phenol was isolated in 1834 and its structure proved in 1842. In 1860 Küchenmeister first used phenol as a wound dressing in Germany. Lister was to use it in his classical experiments in antiseptic surgery. Substituted phenols, and to some extent phenol itself, are still in use today as antiseptics, disinfectants and preservatives.

Anti-Infective Agents↗
PubMed1979

Inhibition of sulfation of phenols in vivo by 2,6-dichloro-4-nitrophenol: selectivity of its action in relation to other conjugations in the rat in vivo.

The effect of 2,6-dichloro-4-nitrophenol, an inhibitor of the sulfation of the phenolic compound harmol in vivo, on the sulfation of other phenolic substances and on various conjugation reactions has been studied in the rat in vivo. Compounds chemically related to 2,6-dichloro-4-nitrophenol were also tested as sulfation inhibitors. 2,6-Dichloro-4-nitrophenol inhibited the sulfation of phenol while it had no effect on biliary excretion of dibromosulphthalein, glucuronidation of phenolphthalein, acetylation of procainamide ethobromide or glutathione conjugation of ethacrynic acid. It is concluded that of these conjugation reactions sulfation is inhibited selectively at the dose level used. Some phenols with chloro- or nitro-substituents effectively inhibited the sulfation of harmol but to a lesser extent than 2,6-dichloro-4-nitrophenol. Many other phenols did not affect the conjugation of harmol, which is both glucuronidated and sulfated.

Animals↗
PubMed1978

[Urine phenol test as an index of exposure to aromatic hydrocarbons].

Results of phenol determinations in urine of the workers of petrochemical combine in Płock have been statistically compared over 10 years. Besides this reaction has been checked in other plants and even in non--exposed persons. Phenol content in urine has been found to increase from year to year, despite very low benzene and phenol concentrations on the work--posts. This trend is also apparent in other plants. Considerations of the nature of the reaction lead to the conclusion that the phenol test informs about a total exposure to hydrocarbons of benzene ring, which metabolize to simple phenols. The authors suggest allowable safe values (65 mg/l) and limit values (about 200 mg/l) of these concentrations.

Air Pollutants↗
PubMed1976

Value of urinary simple phenol and indican determinations in the diagnosis of the stagnant loop syndrome.

The urinary excretion of phenol, p-cresol, and indican was determined in 7 patients with the stagnant loop syndrome, 26 patients with coeliac disease, chronic pancreatitis, and partial gastrectomy, and 18 control patients. The mean excretion of the compounds in the patients with the stagnant loop syndrome and in the control patients, respectively, was 77 and 2.3 mg/24 h of phenol (p less than 0.05), 164 and 39.5 mg/24 h of p-cresol (n.s.), and 369 and 41.5 mg/24 h of indican (p less than 0.01). When applied as diagnostic tests for the stagnant loop syndrome, the phenol excretion showed 2 false negative results, the p-cresol excretion 3 false negative and 2 false positive results, and the indican excretion 6 false positive results. The combined use of phenol and indican determinations eliminated the number of false positive results with the indican test, and was found most useful as screening procedure. Determination of phenol and indican in a 24-hour urine sample is likely to provide a simple method for selecting patients with signs of abnormal bacterial colonization in the small intestine for more detailed investigations.

Aged↗