Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.17.3.2 (xanthine oxidase)
8,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A RP-HPLC method was developed for the assessment of caffeine and its metabolites in urine and was used for the evaluation of the CYP1A2, CYP2A6, xanthine oxidase (XO) and N-acetyl-transferase-2 (NAT-2) in vivo activities in 44 Greek volunteers (21 men, 23 women). Spot urine samples were analyzed 6 h after 200 mg caffeine consumption, following a 30 h methylxantine-free diet. The major urinary caffeine metabolites are 1-methyluric acid (1U), 5-acetylamino-6-formylamino-3-methyluracil (AFMU), 1-methylxanthine (1X), 1,7-dimethyluric acid (17U) and 1,7-dimethylxanthine (17X). CYP1A2, CYP2A6, XO and NAT-2 activities were estimated from the metabolic ratios (AFMU + 1U + 1X)/17U, 17U/17X, 1U/(1X + 1U) and AFMU/(AFMU + 1U + 1X), respectively. Metabolites and internal standard were extracted with chloroform/isopropanol (85:15, v/v) and separated on a C18 column by an isocratic HPLC system using a two-step elution with manual switch from solvent A (0.1% acetic acid-methanol-acetonitrile, 92:4:5 v/v) to solvent B (0.1% acetic acid-methanol, 60:40, v/v), and detected at 280 nm. The method exhibited adequate metabolite separation (resolution factors >1.48), accuracy (94.1-106.3%) and intraday and interday precision <8.02 and <8.78%, respectively (n = 6). Smoking affected only CYP1A2, whereas gender had no effect in any enzyme activity. NAT-2 exhibited bimodal distribution, 63.6% of volunteers being slow acetylators. The developed RP-HPLC method was fully validated and successfully applied for the evaluation of CYP1A2, CYP2A6, XO and NAT-2 activities.
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PMID:In vivo evaluation of CYP1A2, CYP2A6, NAT-2 and xanthine oxidase activities in a Greek population sample by the RP-HPLC monitoring of caffeine metabolic ratios. 1722 22

An in vitro bioassay-guide revealed that the methanol (MeOH) extract of the stem bark of Populus davidiana showed considerable inhibitory activity against cyclooxygenase (COX-1, COX-2). Continuous phytochemical study of the MeOH extract of this plant led to the isolation of ten flavonoids; sakuranetin (1), rhamnocitrin (2), 7-O-methylaromadendrin (3), naringenin (4), eriodictyol (5), aromadendrin (6), kaempferol (7), neosakuranin (8), sakuranin (9) and sakurenetin-5,4'-di-beta-D-glucopyranoside (10). Their structures were identified on the basis of their physicochemical and spectroscopic analyses. The isolated compounds, 1-10, were tested for their inhibitory activities against COX-1 and COX-2. Compound 7 was found to have potent inhibitory effect on COX-1 and a moderate effect on COX-2, meanwhile, compounds 1-6 showed moderate inhibition against COX-1 only. Moreover, compounds 5-8 exhibited suppressive effects on xanthine oxidase (XO). These results may explain, in part, the traditional uses of P. davidiana in ethnomedicine.
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PMID:Anti-inflammatory activity of flavonoids from Populus davidiana. 1722 58

Two supramolecular complexes, [Cu(L)(H2O)2(beta-CD)](ClO4)2.10.5H2O.CH3OH (1) and [Cu(L)(H2O)2(beta-GCD)](HClO4)(ClO4)2.10H2O (2) (L = 4-(4'-tert-butyl-benzyl)diethylenetriamine, beta-CD = beta-cyclodextrin, and beta-GCD = mono-6-deoxy-6-guanidinocycloheptaamylose cation), have been synthesized. The structure of 1 has been characterized by X-ray crystallography. The 4-tert-butyl-benzyl of [Cu(L)(H2O)2]2+ moiety in 1 as a guest inserts into the hydrophobic cavity of the beta-CD as a host along the primary hydroxyl side. On the basis of the structure data of 1, complex 2 was modeled, which showed that the distance between the Cu and C atom of the guanidinium is 5.2 A, comparable to the corresponding distance in bovine erythrocyte Cu, Zn-SOD (5.9 A) (SOD = superoxide dismutase). Apparent inclusion stability constants of the host and the guest were measured to be 0.66 (+/-0.01) x 104 and 1.15 (+/-0.03) x 104 M-1 for 1 and 2 respectively. The electronic absorption bands and electronic reflection bands of each complex are almost the same, indicating an identical structure of the complex in aqueous solution and in solid state. The two complexes showed quasi-reversible one-electron Cu(II)/Cu(I) redox waves with redox potentials of -0.345 and -0.338 V for 1 and 2, respectively. Their SOD-like activities (IC50) were measured to be 0.30 +/- 0.01 and 0.17 +/- 0.01 microM by xanthine/xanthine oxidase-NBT assay. The enhanced SOD activity of 2 by approximately 40% compared with 1 suggests that the guanidyl cation in the host of the supramolecular system of 2 can effectively mimic the side chain of Arg141 in the enzyme, which is known to be essential for high SOD activity possibly through steering of the superoxide substrate to and from the active copper ion.
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PMID:Synthesis, structure, and activity of supramolecular mimics for the active site and arg141 residue of copper, zinc-superoxide dismutase. 1725 14

The ability of three Rhamnus alaternus leaves extracts on antigenotoxic and gene expression level effects was respectively investigated in a bacterial assay system, i.e. the SOS chromotest with Escherichia coli PQ37 and in human K562 lymphoblast cell line. Total oligomers flavonoids (TOF) enriched, methanol and ethyl acetate extracts were prepared from powdered R. alaternus leaves and characterized quantitatively for the presence of polyphenolic compounds. We explored the response to oxidative stress using the transcriptional profile of genes in K562 cells stressed with H2O2 after incubation with plant extracts. For this purpose, we used a cDNA microarrays containing 82 genes related to cell defense, essentially represented by antioxidant and DNA repair genes. Analysis revealed that SOD1, AOE 372, TXN genes involved in the antioxidant defense system and XPC, LIG4, POLD2, PCNA genes implied in the DNA repair system were among the most expressed ones in the presence of the tested extracts. These results were in accordance with those obtained when we tested the antigenotoxic and antioxidant effects of the same extracts with, respectively the SOS chromotest and the xanthine/xanthine oxidase enzymatic assay system. The effect of the tested extracts on SOS response induced by both Aflatoxin B1 (AFB1: 10 microg/assay) and nifuroxazide (20 microg/assay) showed that the TOF extract exhibited the highest antimutagenic level towards the indirect mutagen AFB1. Whereas ethyl acetate extract showed the highest antimutagenic effect towards the direct mutagen, nifuroxazide. None of the tested extracts induced mutagenic activity. However all the tested extracts exhibited xanthine oxidase inhibiting and superoxide anions scavenging effects. R. alaternus extracts contain compounds with significant antioxidant and antigenotoxic activities. These compounds modulate gene expression as detected by using cDNA arrays.
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PMID:Transcriptional response of genes involved in cell defense system in human cells stressed by H2O2 and pre-treated with (Tunisian) Rhamnus alaternus extracts: combination with polyphenolic compounds and classic in vitro assays. 1751 22

This study was conducted to search for xanthine oxidase (XO) inhibitors from the root extracts of Tamus communis L. traditionally used in folk medicine in Algeria. Root extracts with different solvents were screened for purified milk xanthine oxidase inhibition. The root extracts (methanol, chloroform and ethyl acetate) and proteins, obtained in distilled water, inhibited bovine, sheep and human milk XO from three species in a concentration-dependent manner, with an additional superoxide scavenging capacity, which reached its highest level with ethyl acetate extract (IC(50) = 0.15, 0.04 and 0.09 g/L) for bovine XO, sheep XO and human XO, respectively. The antioxidant potential was confirmed with the non-enzymatic method, total radical-trapping antioxidant parameter (TRAP) assay, which showed that the Tamus communis L. extracts have a potential antioxidant activity in the same order obtained by using the reduction of cytochrome c, an enzymatic method, in which the antioxidant activity followed a decreasing order: ethyl acetate extract > chloroform extract > protein.
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PMID:Antioxidant properties and xanthine oxidase inhibitory effects of Tamus communis L. root extracts. 1884 60

The mutagenic potential of total aqueous, total oligomers flavonoids (TOF), ethyl acetate (EA), chloroform (Chl), petroleum ether (PE) and methanol (MeOH) extracts from aerial parts of Moricandia arvensis was assessed using Ames Salmonella tester strains TA100 and TA1535 with and without metabolic activation (S9), and using plasmid pBluescript DNA assay. None of the different extracts produced a mutagenic effect, except aqueous extract when incubated with Salmonella typhimurium TA100 after metabolic activation. Likewise, the antimutagenicity of the same extracts was tested using the "Ames test". Our results showed that M. arvensis extracts possess antimutagenic effects against sodium azide (SA) in the two tested Salmonella assay systems, except metabolized aqueous and PE extracts when tested with S. typhimurium TA100 assay system. Different extracts were also found to be effective in protecting plasmid DNA against the strand breakage induced by hydroxyl radicals, except PE and aqueous extracts. Antioxidant capacity of the tested extracts was evaluated using the enzymatic (xanthine/xanthine oxidase assay) (X/XOD) and the non enzymatic (NBT/Riboflavine assay) systems. TOF extract was the more effective one in inhibiting both xanthine oxidase activity and NBT reduction.
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PMID:Moricandia arvensis extracts protect against DNA damage, mutagenesis in bacteria system and scavenge the superoxide anion. 1901 21

Three extracts were prepared from the leaves of Acacia salicina: aqueous, methanol, and ethyl acetate extracts. The antigenotoxic properties of these extracts were investigated by assessing the inhibition of mutagenicity of the indirect-acting mutagen benzo[a]pyrene using the Ames assay and the genotoxicity of the direct-acting mutagen, hydrogen peroxide, using the "Comet assay." Aqueous, methanol, and ethyl acetate extracts at doses of 500, 50, and 500 microg per plate reduced benzo[a]pyrene mutagenicity by 95%, 82%, and 40%, respectively, in Salmonella typhimurium TA98 strain and by 91%, 66% and 63%, respectively, at the same doses with a TA97 assay system. Human lymphoblast cells K562 were pretreated with 50% inhibition concentration of each extracts and then treated by H(2)O(2), for the Comet assay. The Comet assay results showed that ethyl acetate and methanol extracts decreased the DNA damage caused by H(2)O(2) by, respectively, 34.8% and 31.3%. We envisaged also the study of the antioxidant effect of these extracts by the enzymatic xanthine/xanthine oxidase assay. Results indicated that methanol and ethyl acetate extracts were potent inhibitors of xanthine oxidase and superoxide anion scavengers. We conclude that these integrated approaches to antigenotoxicity and antioxidant assessment may be useful to help compare the beneficial effects associated with using A salicina as medicinal and dietary plant.
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PMID:Acacia salicina extracts protect against DNA damage and mutagenesis in bacteria and human lymphoblast cell K562 cultures. 1908 7

Morinda citrifolia L. (noni), family Rubiaceae, has been used in Polynesia for over 2000 years for its reputed health benefits, one of which is its therapeutic effects on gout (langa e hokotanga hui). However, its healing mechanism has not been elucidated. This study showed that in an in vitro bioassay that Tahitian Noni Juice (TNJ) inhibited xanthine oxidase (XO) concentration dependently. Concentrations of 1, 5 and 10 mg/mL of TNJ inhibited XO by 11%, 113% and 148%, respectively, with an IC50 of 3.8 mg compared with an IC50 of 2.4 microm for allopurinol. Noni fruit juice concentrate (NFJC) also inhibited XO concentration dependently. Concentrations of 1 and 5 mg/mL NFJC inhibited XO in vitro by 184% and 159%, respectively. A 0.1 mg/mL methanol extract (NFJME) from the fractionation of noni fruit puree inhibited XO by 64%. It was elucidated that the noni fruit juice inhibitory effect on XO enzymes is the mechanism by which noni ameliorates gout and gout-like diseases. Further, the results also support the traditional usage of noni in the treatment of gout.
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PMID:Xanthine oxidase inhibiting effects of noni (Morinda citrifolia) fruit juice. 1943 57

For centuries, plants have been used in traditional medicines, and there has been recent interest in the chemopreventive properties of compounds derived from plants. In the present study, we investigated the free-radical-scavenging, antioxidant, and antimutagenic potential of polar extracts from Phlomis crinita Cav. flowers. Ethyl acetate, chloroform, and methanol extracts were prepared from powdered Phlomis flowers and characterized for the presence of tannins, flavonoids, iridoids, sterols, cardiac glycosides, and anthraquinones. All the extracts showed increased activity in scavenging the ABTS free radical, but only ethyl acetate and methanol extracts were active in scavenging the superoxide anion generated by the xanthine/xanthine oxidase system. In addition, all the extracts significantly decreased the mutagenicity induced by 2-aminoanthracene in the presence of a metabolizing homogenate (S9) and methyl methane sulfonate in the absence of metabolizing system, using the Ames test with Salmonella typhimurium TA102 and TA104. The present study indicates that extracts of P. crinita flowers are a significant source of compounds with antigenotoxic and antioxidant activity (most likely phenolic compounds) and thus may be useful candidates for chemoprevention studies.
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PMID:Screening of antimutagenicity via antioxidant activity in different extracts from the flowers of Phlomis crinita Cav. ssp mauritanica munby from the center of Tunisia. 1953 26

Vaccinium uliginosum L. (also known as bog bilberry) is a low-growing deciduous shrub classified in the Ericaceae family of plants, which includes numerous Vaccinium berries, blueberries, and cranberries. Berries of the Ericaceae family are known to contain organic acids, vitamins, glycosides, and anthocyanins and have been reported to have antioxidant activity. In order to identify the antioxidative principles of V. uliginosum, we separated water extracts into polyphenol, anthocyanin-rich (pigment), and sugar/acid fractions by using ethyl acetate, acidic methanol (MeOH), and 0.01 N HCl. Antioxidant activities were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide radical, and hydroxyl radical assays. The crude extract and fractions containing polyphenol and pigment exhibited the greatest antioxidant activities with 50% inhibitory concentration (IC(50)) values of 85.8 microg/mL, 33.2 microg/mL, and 16.7 microg/mL, respectively, for the DPPH assay and 48.1 microg/mL, 83.8 microg/mL, and 51.9 microg/mL for the nonenzymatic superoxide radical assay. The fractions containing polyphenol, pigment, and sugar/acid significantly inhibited xanthine oxidase. To investigate the functional compounds from the active fractions, we purified the polyphenol fraction and separated the compounds by using chromatographic techniques. The crude extract was dissolved in MeOH and further purified by reversed-phase high-performance liquid chromatography (HPLC) using MeOH-water (35:65 vol/vol) (with 0.04% trifluoroacetic acid) to obtain VU-EA-1 (16.6 mg), VU-EA-2 (8.5 mg), VU-EA-3 (19.8 mg), VU-EA-4 (12.8 mg), VU-EA-5 (6.5 mg), and VU-EA-6 (23.5 mg). The MeOH-washed fraction from the HPLC was concentrated and purified by reversed-phase HPLC using MeOH-water (50:50 vol/vol) to give VU-EA-10 (12.4 mg). Antioxidant activity was assessed by DPPH, superoxide radical, and hydroxyl radical assays. The isolated compounds exhibited dose-dependent antioxidant activity with IC(50) values of 7.6 microg/mL (VU-EA-10) for the DPPH assay, 67.8 microg/mL (VU-EA-4) for the nonenzymatic superoxide radical assay, and 3.7 microg/mL (VU-EA-10) and 7.6 microg/ml (VU-EA-6) for the enzymatic superoxide radical assay and 30% inhibitory concentration values of 0.58 microg/mL (VU-EA-1), 0.57 microg/mL (VU-EA-5), and 0.70 microg/mL (VU-EA-6) for the hydroxyl radical assay. In conclusion, V. uliginosum had potent antioxidative activity, and flavonoids were isolated as the main active principles.
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PMID:Antioxidant activities of Vaccinium uliginosum L. extract and its active components. 1973 91


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