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PubMed1981

The study on the biological fate of paraben at the dose of practical usage in rat. III. The effects of salicylic acid on the fate of ethyl paraben.

The biological fates of ethyl paraben were investigated after the simultaneous administration with salicylic acid. Those fates were compared with those of ethyl paraben alone obtained in the previous experiments. The biological fates of ethyl paraben after the simultaneous administration with salicylic acid were different from those of ethyl paraben alone as reported in the previous reports. The excretion of unconjugated p-hydroxybenzoic acid, which is a hydrolyzed product of ethyl paraben, increased and those of p-hydroxyhippuric acid, glycine conjugate of p-hydroxybenzoic acid, and p-hydroxybenzoyl glucuronide, its ester type glucuronide, decreased. The blood concentration patterns were considerably different from those of ethyl paraben alone, especially the elimination of every metabolite was delayed. Pharmacokinetic analyses on the data of blood concentration were carried out and the results also show the interaction of salicylic acid on the biological fate of ethyl paraben.

Animals↗
PubMed2001

Fast homogeneous assay for plasma procarboxypeptidase U.

Carboxypeptidase U (EC 3.4.17.20, CPU, TAFIa) is a novel determinant of the fibrinolytic rate. It circulates as an inactive zymogen, procarboxypeptidase U, which becomes active during the process of coagulation. We developed a high throughput method on microtiter plates for the determination of the procarboxypeptidase U concentration in human plasma samples. Following activation of procarboxypeptidase U by thrombin-thrombomodulin, the resulting enzyme activity cleaves p-OH-Hip-Arg and the generated p-OH-hippuric acid is converted by hippuricase to p-hydroxybenzoic acid and glycine. Finally, oxidative coupling of p-hydroxybenzoic acid with 4-aminoantipyrine by NaIO4 forms the quinoneimine dye. The absorbance of the latter dye is determined at 506 nm in a microtiter plate reader. A mean value of 620 U/l was found, with a CV of 3.0% within-run and 4.3% between-run. The assay showed a good correlation with the activities observed using a HPLC assay as reference method (n = 25, r = 0.979). The presented method enables the routine analysis of large sample pools in clinical setting.

Adult↗
PubMedDate not supplied

Phenolic compounds and flavonoids as plant growth regulators from fruit and leaf of Vitex rotundifolia.

Five phenolic compounds, 4-hydroxybenzoic acid methyl ester (1), vanillic acid methyl ester (2), 4-hydroxy benzaldehyde (3), 4-hydroxybenzoic acid (4) and ferulic acid (5), and four flavonoids, 5,5'-dihydroxy-4',6,7-trimethoxyflavanone (6), luteolin (7), vitexicarpin (8) and artemetin (9), were isolated from fruits and leaves of Vitex rotundifolia L. The biological activities of these nine compounds have been examined using a bioassay with lettuce seedlings.

Flavonoids↗
PubMed2006

Enantioselective substrate binding in a monooxygenase protein model by molecular dynamics and docking.

The two-component flavoenzyme styrene monooxygenase (SMO) is an efficient alternative to several chemical epoxidation catalysts on a preparative scale. A first homology model of the catalytic domain (StyA) of SMO was constructed (Protein Data Bank ID 2HD8) based on the structure of para-hydroxybenzoate hydroxylase. The StyA protein structure was optimized by restrained molecular dynamics to reproduce specific pre-S binding orientations of styrene. Effects of all 10 point mutations examined were explained by the distance of the site to the styrene and FAD binding sites. Thirteen of 20 ligands could be accommodated in a catalytically active binding orientation, and predicted affinities correlated well with experimental turnover and inhibition. The binding cavity is almost completely hydrophobic except for a hydrogen-bonded network formed by three water molecules, the backbone of residues 300-302, and the flavin ribityl, similar to P293, and three crystal waters in para-hydroxybenzoate hydroxylase suggest that P302, T47, and the waters in StyA are a vital component of the catalytic mechanism. The current optimized and validated StyA model provides a good starting point for elucidation of the structural basis of StyA ligand binding and catalysis. Novel insights in the binding of ligands to SMO/StyA, provided by the current protein model, will aid the rational design of mutants with specific, altered enantioselective properties.

Binding Sites↗
PubMed2002

Retention of anions on silica-based metalloporphyrin stationary phases.

The silica-based Fe(III)-protoporphyrin and Zn-tetraphenylporphyrin stationary phases were examined for the HPLC separation of anions. The retention of nine common inorganic anions as well as benzoate anion (BA) and its hydroxy analogues (HBA) was examined using tartrate, acetate, and succinate eluents. The retention factors of inorganic anions on the FeProP stationary phase were in the order Cl- < NO3- < ClO4- < I- < SCN- and for organic anions benzoate < p-hydroxybenzoate < m-hydoxybenzoate < o-hydroxybenzoate. The retention factors of organic anions examined for a ZnTPP column were in the order p-HBA < m-HBA < BA < o-HBA.

Journal Article↗
PubMed1993

Oral challenge with alternative nonsteroidal antiinflammatory drugs (NSAIDs) and paracetamol in patients intolerant to these agents.

The reliability and safety of the oral challenge procedure were evaluated in the diagnosis and prevention of intolerance to nonsteroidal anti-inflammatory drugs (NSAIDs). 112 NSAID-intolerant patients were submitted to oral challenge with aspirin (acetylsalicylic acid), dipyrone, paracetamol, imidazole-hydroxybenzoate or nimesulide to confirm historic intolerance and to evaluate tolerance to other NSAIDs. A significant correlation was demonstrated between history of intolerance and the results of oral challenge in aspirin-intolerant patients (p < 0.001). Of 237 challenges with various NSAIDs and paracetamol in 101 patients, 19 challenges were positive and 2 patients developed anaphylactic shock. The ratio of positive: total challenges with alternative NSAIDs and paracetamol were as follows: 7 of 83 for paracetamol, 2 of 49 for imidazole-hydroxybenzoate and 0 of 30 for nimesulide. On the basis of these results, nimesulide was evaluated as an alternative NSAID in a second group of 284 NSAID-intolerant patients. Challenge with nimesulide elicited a positive response in 14 patients (in 6 patients the response was delayed), although adverse reactions were mild in all instances. In conclusion, a positive history of intolerance to a given NSAID is a sufficient reason to contraindicate its use even for diagnostic purposes, e.g. oral challenge. Oral challenge should therefore be restricted to the assessment of the tolerability of alternative NSAIDs. In the present study nimesulide appeared to be the safest currently available alternative in patients with NSAID intolerance.

Acetaminophen↗
PubMed1982

Metabolism and excretion of benzo[a]pyrene in the rabbit.

1. Following i.v. administration of [14C]benzo[a]pyrene (3 mumol/kg) to rabbits, 30% of the 14C dose appeared in bile and 12% in urine, within six hours. 2. Biliary and urinary metabolites were mainly conjugated; less than 12% of the 14C was extractable with ethyl acetate, but after treatment with beta-glucuronidase or aryl sulphatase 30-40% became extractable. 3. H.p.l.c. analysis of the extracts indicated that the major non-polar metabolite was benzo[a]pyrene, 9,10-diol (18% of 14C in bile and 24% of 14C in urine, mainly conjugated with glucuronic acid). Smaller amounts of the 4,5-diol, the 3,6-quinone, and the 9-hydroxy- and 3-hydroxybenzo[a]pyrene were also found in bile (total less than 10%), together with 9-hydroxybenzo[a]pyrene and two unknown metabolites (X and Y) in urine (total less than 4%). 4. The proximate carcinogen, the 7,8-diol, was not detected in any extract. 5. After intraduodenal administration of biliary metabolites of [14C]benzo[a]pyrene (approx. 0 X 3 mumol), 14C was excreted in the bile (21% dose) and urine (14%) within 23 h, indicating that metabolites can undergo enterohepatic circulation in the rabbit.

Animals↗
PubMed1983

The biotransformation of three 14C-labelled phenolic compounds in twelve species of freshwater fish.

1. The urinary and biliary excretion of 14C-labelled m-cresol, 1-naphthol and o-chlorophenol were investigated in 12 species of freshwater fish (bitterling, Rhodeus sericeus amarus; bream, Abramis brama; crucian carp, Carassius carassius; goldfish, Carassius auratus; gudgeon, Gobio gobio; guppy, Poecilia reticulata; minnow, Phoximus phoximus; perch, Perca fluviatilis; roach, Rutilus rutilus; rudd, Scardinius erythropthalmus; three-spined stickleback, Gasterosteus aculeatus; tench, Tinca tinca) when immersed in sub-lethal concentrations of the compounds in the aquarium water for 48 h. 2. The sulphate and glucuronic acid conjugates of 1-naphthol and o-chlorophenol were detected in both the aquarium water and the bile of all the fish species. 3. The oxidation product of m-cresol, m-hydroxybenzoic acid, and the sulphate conjugate of the phenol, were excreted into the aquarium water of all species except the guppy, which did not excrete m-hydroxybenzoic acid. In addition to these two metabolites, the glucuronic acid conjugate of m-cresol was found in the bile of all species, except for guppies whose small size precluded study of biliary excretion.

Animals↗
PubMed1992

Inhibition of rat hepatic aryl sulphotransferase IV by dihydrodiol derivatives of benzo[a]pyrene and naphthalene.

1. Although neither the (+)- nor (-)-enantiomer of trans-benzo[a]pyrene-7,8-dihydrodiol was a substrate for aryl sulphotransferase IV from rat liver, both enantiomers inhibited the enzyme-catalysed sulphation of 1-naphthalene-methanol with Ki values of 3.7 +/- 0.4 microM for the (+)-enantiomer, and 4.4 +/- 0.3 microM for the (-)-enantiomer. 2. Based on the magnitude of the Ki values, the binding affinity of these dihydrodiols for the aryl sulphotransferase was significantly greater than that for the corresponding phenolic derivatives of benzo[a]pyrene. That is 7-hydroxybenzo[a]pyrene and 8-hydroxybenzo[a]pyrene were both substrates for aryl sulphotransferase IV, with apparent Km values of 280 +/- 41 microM and 370 +/- 72 microM, respectively. 3. Both (+)- and (-)-trans-naphthalene-1,2-dihydrodiols were also inhibitors of aryl sulphotransferase IV, but with higher Ki values than would be expected from previously determined apparent Km and Ki values for (R)-(-)- and (S)-(+)-1,2,3,4-tetrahydro-1-naphthols, respectively.

Animals↗
PubMed2001

Estimation of preservative concentrations in foods and their daily intake based on official inspection results in Japan in fiscal year 1998.

The mean concentration and daily intake of five preservatives were estimated based on the results of an analysis of 89,927 samples of food obtained in official inspections by Japanese local governments in fiscal year 1998. The mean concentration of benzoic acid was 9.5% of the allowable limit, and those of dehydroacetic acid, p-hydroxybenzoic acid, propionic acid, and sorbic acid were 1.5%, 5.7%, 1.7%, and 23.9%, respectively. Daily intake levels of these preservatives per person estimated from the concentration and daily consumption of foods were 6.23 mg, 0.0303 mg, 1.02 mg, 8.10 mg, and 25.0 mg, respectively, and assuming a body weight of 50 kg, the amounts of benzoic acid, p-hydroxybenzoic acid, and sorbic acid consumed were 2.5%, 0.2%, and 2.0% of their acceptable daily intakes, respectively. These values were similar to those obtained based on the results of the official inspections in fiscal years 1994 and 1996.

Benzoic Acid↗
PubMed2004

New aminocoumarin antibiotics from a cloQ-defective mutant of the clorobiocin producer Streptomyces roseochromogenes DS12.976.

Three new antibiotics, vanillobiocin, isovanillobiocin and declovanillobiocin, were isolated from the culture broth of a cloQ-defective mutant of the clorobiocin producer Streptomyces roseochromogenes, which is blocked in the biosynthesis of the prenylated 4-hydroxybenzoic acid moiety of clorobiocin. Spectroscopic analysis showed that the isolated compounds were similar to clorobiocin, but contained vanillic acid as the acyl component instead of the prenylated 4-hydroxybenzoic acid present in clorobiocin. Isovanillobiocin differs from vanillobiocin by the position of the pyrrole unit attached to the sugar moiety of the antibiotic. Declovanillobiocin lacks the chlorine atom at the aminocoumarin ring. All three compounds had lower antibiotic activity against Bacillus subtilis than clorobiocin.

Anti-Bacterial Agents↗
PubMed1999

Regulation and function of family 1 and family 2 UDP-glucuronosyltransferase genes (UGT1A, UGT2B) in human oesophagus.

Human UDP-glucuronosyltransferases (UGTs) are expressed in a tissue-specific fashion in hepatic and extrahepatic tissues [Strassburg, Manns and Tukey (1998) J. Biol. Chem. 273, 8719-8726]. Previous work suggests that these enzymes play a protective role in chemical carcinogenesis [Strassburg, Manns and Tukey (1997) Cancer Res. 57, 2979-2985]. In this study, UGT1 and UGT2 gene expression was investigated in human oesophageal epithelium and squamous-cell carcinoma in addition to the characterization of individual UGT isoforms using recombinant protein. UGT mRNA expression was characterized by duplex reverse transcriptase-PCR analysis and revealed the expression of UGT1A7, UGT1A8, UGT1A9 and UGT1A10 mRNAs. UGT1A1, UGT1A3, UGT1A4, UGT1A5 and UGT1A6 transcripts were not detected. UGT2 expression included UGT2B7, UGT2B10 and UGT2B15, but UGT2B4 mRNA was absent. UGT2 mRNA was present at significantly lower levels than UGT1 transcripts. This observation was in agreement with the analysis of catalytic activities in oesophageal microsomal protein, which was characterized by high glucuronidation rates for phenolic xenobiotics, all of which are classical UGT1 substrates. Whereas UGT1A9 was not regulated, differential regulation of UGT1A7 and UGT1A10 mRNA was observed between normal oesophageal epithelium and squamous-cell carcinoma. Expression and analysis in vitro of recombinant UGT1A7, UGT1A9, UGT1A10, UGT2B7 and UGT2B15 demonstrated that UGT1A7, UGT1A9 and UGT1A10 catalysed the glucuronidation of 7-hydroxybenzo(alpha)pyrene, as well as other environmental carcinogens, such as 2-hydroxyamino-1-methyl-6-phenylimidazo-(4, 5-beta)-pyridine. Although UGT1A9 was not regulated in the carcinoma tissue, the five-fold reduction in 7-hydroxybenzo(alpha)pyrene glucuronidation could be attributed to regulation of UGT1A7 and UGT1A10. These data elucidate an individual regulation of human UGT1A and UGT2B genes in human oesophagus and provide evidence for specific catalytic activities of individual human UGT isoforms towards environmental carcinogens that have been implicated in cellular carcinogenesis.

Aged↗
PubMed1999

Cloning and sequencing of the fcbB gene encoding 4-chlorobenzoate-coenzyme A dehalogenase from Pseudomonas sp. DJ-12.

Pseudomonas sp. DJ-12 degrades 4-chlorobenzoate through hydrolytic dechlorination to produce 4-hydroxybenzoate and a chloride ion. The fcbB gene encoding the 4-chlorobenzoate-coenzyme A (4CBA-CoA) dehalogenase which catalyzes the nucleophilic substitution reaction to convert 4CBA-CoA to 4-hydroxybenzoate-coenzyme A (4HBA-CoA) in the consecutive steps of dechlorination was cloned from the chromosome of the organism. A nucleotide sequence analysis of the gene showed an open reading frame consisting of 810 nucleotides, which can encode for a polypeptide of molecular mass 30 kDa, containing 269 amino acid residues. A promoter-like sequence (-35 and -10 region) and a putative ribosome-binding sequence were identified. A deduced amino acid sequence of the 4CBA-CoA dehalogenase showed 86%, 50%, and 50% identity with those of corresponding enzymes in the Pseudomonas sp. CBS3, Arthrobacter sp. SU, and Arthrobacter sp. TM1, respectively.

Amino Acid Sequence↗
PubMedDate not supplied

[Microbial degradation of components of waste water from phenol-producing industry].

Processes of aerobic biodegradation of components of phenol production sewage (phenol, acetophenone, dimethylphenylcarbinol, cumene hydroperoxide, alpha-methylstyrene, benzoate, and p-hydroxybenzoate) by bacterial strains obtained from the collection of Saratov Institute of Biocatalysis were studied. The metabolic reactions were shown to be oxidative and have a common catabolic sequence (cumene hydroperoxide-dimethylphenyl-carbinol alpha-methylstyrene-acetophenone-phenyl acetate-phenol-pyrocatechol-aromatic ring breakage). Benzoate and p-hydroxybenzoate were degraded through the formation of pyrocatechol and protocatechuate, respectively. Metabolic pathways were similar in model mixtures of components and sewage samples.

Biodegradation, Environmental↗
PubMed1992

Interaction of preservatives with macromolecules: Part I--Natural hydrocolloids.

Antibacterial activity of methyl-p-hydroxybenzoate against Ps. aeruginosa was evaluated in the presence of varying concentrations of acacia, tragacanth, sodium alginate, guar gum and carrageenin. All these hydrocolloids reduced the antibacterial activity to varying degrees. Tragacanth and guar gum inhibited the activity to a greater extent than acacia, sodium alginate and carrageenin. Hydrocolloids reduce the antibacterial activity of preservatives in two ways. Interaction of the preservative with hydrophilic macromolecules and subsequent reduction in the availability of preservative appears to be the predominant mechanism by which tragacanth and guar gum reduce the activity of methyl-p-hydroxybenzoate. Acacia, sodium alginate and carrageenin apparently act by offering physical protection to microbial cells from the action of the preservative. It is also probable that these hydrocolloids provide more favourable media for microbial growth thereby increasing the preservative requirement for adequate preservation.

Colloids↗
PubMed1992

Determinants of polycyclic aromatic hydrocarbon-DNA adducts in human placenta.

To determine the relative contributions of tobacco smoking and P-450 metabolism (cytochrome P-450IAI) in the formation of benzo(a)pyrenediol-epoxide and other polycyclic aromatic hydrocarbon-DNA adducts in vivo, 16 human placentas were assayed for aryl hydrocarbon hydroxylase activity and (+/-)r-7,t-8-dihydroxy-c-9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene-DN A adduct levels. Immunoaffinity chromatography columns, conjugated with monoclonal antibodies raised against benzo(a)-pyrene-diol-epoxide-deoxyguanosine, were used to concentrate polycyclic aromatic hydrocarbon-DNA adducted nucleotides, and synchronous fluorescence spectroscopy was used specifically to detect r-7,t-8,t-9,c-10-tetrahydroxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BP-tetrol) extracted from acid hydrolysates of immunoconcentrated materials. Data were analyzed for associations with maternal dietary and smoking habits, umbilical cord blood cotinine levels, and placental aryl hydrocarbon hydroxylase levels. Complex mixtures of fluorescent materials were present in organic solvent extracts of acid hydrolysates of immunoconcentrated nucleotide-adducts from all placentas with patterns of fluorescence that may be associated with tobacco smoking determined by generation of spectral fluorescence excitation-emission matrices. BP-tetrols were detected in extracts from 8 placentas: 5 of 7 from smokers and 3 of 9 from nonsmokers. Placental aryl hydrocarbon hydroxylase activity was significantly higher in placentas from which BP-tetrols were extracted [3.9 +/- 2.4 [corrected] (mean +/- SE) pmol 3-hydroxybenzo(a)pyrene mg protein-1 min-1], than among placentas from which BP-tetrols were not extracted (0.4 +/- 0.2 [corrected] pmol 3-hydroxybenzo(a)pyrene mg protein-1 min-1) (P = 0.03, Student's t test). This association was independent of maternal smoking or umbilical cord blood cotinine levels. These results indicate that while maternal tobacco smoking is associated with the accumulation of putative, but as yet unidentified, polycyclic aromatic hydrocarbon-DNA adducts in placenta, metabolic capacity appears to be the principal determinant for the (+/-)r-7,t-8-dihydroxy-c-9,10 epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene-DNA adduct levels detected.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed2005

[The biotransformation of kaempferitrin by human intestinal flora].

AIM: To study the biotransformation of kaempferitrin, a major chemical principle of the fruits of Siraitia grosvenori (Swingle) C. Jeffery, with human intestinal flora. METHODS: The kaempferitrin was incubated with human intestinal flora. The biotransformation products were isolated and purified by chromatographic methods and the structures were determined by spectroscopic techniques. RESULTS: Kaempferitrin was converted into kaempferol 3-O-alpha-L-rhamnoside (afzelin, I) , kaempferol 7-O-alpha-L-rhamnoside (II), kaempferol (III) and p-hydroxybenzoic acid (IV) by human intestinal flora. rhamnoside (II), kaempferol (III) and p-hydroxybenzoic acid (IV) by human intestinal flora. CONCLUSION: The structure of kaempferitrin can be biotransformatedly converted by human intestinal flora.

Bacteria↗
PubMed2006

[Inhibitory effects of Lantana camera and its contained phenolic compounds in Eichhornia crassipes growth].

This paper studied the effects of Lantana camera fresh leaves aqueous extract and its contained phenolic compounds on the growth and physiologic-biochemical indexes of Eichhornia crassipes. The results showed that this extract had obvious inhibitory effects on the growth and development of E. crassipes. When the concentration was higher than 30 g FW x L(-1), it could kill E. crassipes after 6 days treatment. A total of seven phenolic compounds in the abstract were identified by HPLC, which were salicylic acid, gentisic acid, beta-resorcylic acid , coumarin, ferulic acid, p-hydroxybenzoic acid and 6-methyl coumarin, with the concentrations being, 50.95, 13.46, 5.28, 3.36, 2.92, 2.19 and 0.34 mg x L(-1), respectively. The mixture of the seven compounds had the strongest inhibitory effect, followed by salicylic acid, 6-methyl coumarin, coumarin, and p-hydroxybenzoic acid, while the effects of beta-resorcylic acid and gentisic acid were not significant.

Eichhornia↗