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Query: KEGG:D02003 (NBT)
 1,323 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antioxidative activities of six phenylpropaniod glycosides (PPG) extracted from Pedicularis striata and Pedicularis lasiophrys for inhibiting the lipid peroxidation induced by Fe2+/ascorbic acid in mouse liver microsome may be related to the number and steric position of phenolic hydroxyl groups (PHG) they possess (32.5 mumol.L-1 to 65.0 mumol.L-1). The scavenging effects of PPG for superoxide produced by NBT/PMS/NADH system may be related to both the number of PHG and their conjugated system (16.0 mumol.L-1 to 65.0 mumol.L-1).
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PMID:Scavenging effects of phenylpropanoid glycosides on superoxide and its antioxidation effect. 130 46

The improved method presented here for localizing monophenoloxidase activity of tyrosinase (E.C. 1.14.18.1) after electrophoresis is based on the transfer of electrons from the monophenolic substrate, tyrosine methyl ester, to an artificial acceptor, phenazine methosulfate, and subsequent reduction of nitro blue tetrazolium into a violet formazan. This method is rapid, sensitive and versatile compared to the standard method. The electron transferred from monophenol can be accepted directly by nitro blue tetrazolium; although the background of the gel is clear, the sensitivity is decreased. The monophenol-PMS-NBT method is suitable for both plant and animal samples. This method can also be used for histochemical demonstration of monophenoloxidase activity.
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PMID:Demonstration of monophenoloxidase activity of tyrosinase after electrophoresis. 171 63

1-Methoxy-5-methylphenazinium methyl sulfate (MPMS) was tested for use as redox mediator in histochemistry of dehydrogenases. Aqueous solutions of MPMS are absolute lightstable. Like PMS or Meldola Blue the succinate dehydrogenase reaction was increased by MPMS. In an non-enzymatic NADH-NBT-test the reaction rate of MPMS exceeds the rates of PMS or Meldola Blue.
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PMID:[1-methoxy-5-methylphenazinium-methylsulfate--a light stabile redox mediator in the histochemistry (author's transl)]. 677 87

Tyrosine hydroxylase and phenoloxidase differ in that tyrosine hydroxylase (E.C.1.14.16.2) can hydroxylate tyrosine into -o-diphenol, but cannot oxidize the -o-diphenol, whereas phenoloxidase (E.C.1.14.18.1) is capable of oxidizing -o-diphenol to quinone. This difference can be exploited by staining tyrosine hydroxylase activity with a substrate-PMS-NBT method and staining the phenoloxidase with a dopamine-MBTH method. Based on the staining properties of the bands separated after electrophoresis, tyrosine hydroxylase has been differentiated from phenoloxidase in the silkworm Bombyx mori and the occurrence of tyrosine hydroxylase has been reported for the first time in this worm.
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PMID:Differentiation of tyrosine hydroxylase and phenol oxidase after electrophoresis. 750 28

We assessed the effect of dipyridamole, RA-642 and mopidamol, on lenticular opacities in a model of experimental diabetic cataracts in rats. All three pyrimido-pyrimidine derivatives caused a statistically significant reduction of opacification in crystalline lens as compared with untreated diabetic animals. The production of superoxide anions (phenazine methosulphate [PMS]-induced nitroblue tetrazolium [NBT] reduction) showed a decrease of 81.6%, 78.9% and 1.8% in lens tissue homogenates from rats treated with dipyridamole, RA-642 and mopidamol, respectively. Dipyridamole and RA-642 produced a statistically significant inhibition (50% and 64.8%, respectively) of lipid peroxidation (ferrous sulphate and ascorbic acid [FeAs]-induced malondialdehyde [MDA] production) as compared with the group of untreated diabetic rats. Mopidamol did not exert any inhibitory effect on lipid peroxidation. There was a statistically significant correlation between opacification of lens and PMS-induced NBT reduction and FeAs-induced MDA production. We conclude that the protective effect of dipyridamole and RA-642 from free radical damage to crystalline lens in the model of experimental diabetes used in this study, is the result of the antioxidant action of these compounds. The effect exerted by mopidamol, however, suggest a possible complementary effect of the pyrimido-pyrimidine derivatives through interaction with other mechanisms (e.g., the sorbitol pathway) implicated in the development of cataracts.
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PMID:The pyrimido-pyrimidine derivatives, dipyridamole and RA-642, reduce opacification of crystalline lens in diabetic rats. 787 Jun 94

The antioxidant properties of silibin complexes, the water-soluble form silibin dihemisuccinate (SDH), and the lipid-soluble form, silibin phosphatidylcholine complex known as IdB 1016, were evaluated by studying their abilities to react with the superoxide radical anion (O2-.), and the hydroxyl radical (OH.). In addition, their effect on pulmonary and hepatic microsomal lipid peroxidation had been investigated. Superoxide radicals were generated by the PMS-NADH system and measured by their ability to reduce NBT. IC50 concentrations for the inhibition of the NBT reduction by SDH and IdB 1016 were found to be 25 microM and 316 microM respectively. Both silibin complexes had an inhibitory effect on xanthine oxidase activity. SDH reacted rapidly with OH radicals at approximately diffusion controlled rate and the rate constant was found to be (K = 8.2 x 10(9) M-1 s-1); it appeared to chelate Fe2+ in solution. In hepatic microsomes, when lipid peroxidation was induced by Fe2+, SDH inhibited by 39.5 per cent and IdB 1016 by 19.5 per cent, whereas when lipid peroxidation was induced by CuOOH, IdB 1016 exerted a better protective effect than SDH (29.4 per cent and 19.4 per cent inhibition, respectively). In both microsomal systems lipid peroxidation proceeded through a thiol depletion mechanism which could be restored in the presence of silibin complexes. Low levels of lipid peroxidation in pulmonary microsomes point out the differences between in-vitro lipid peroxidation occurring in microsomes of different tissues. The results support the free radical scavenger and antioxidative properties of silibin when it is complexed with a suitable molecule to increase its bioavailability.
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PMID:Free radical scavenging and antioxidative properties of 'silibin' complexes on microsomal lipid peroxidation. 907 34

L-Glutamate dehydrogenase (GLDH) independent of NAD(P) and oxygen was first obtained from the psychrotrophic bacterium Aeromonas sp. L101, originally isolated from the organs of salmon (Oncorhynchus keta). GLDH was purified by a series of chromatography steps on DEAE-Sepharose, Superdex 200pg, Q-Sepharose, CM-Sepharose, and Phenyl-Sepharose. The purified protein was determined to have a molecular mass of 110 kDa and a pI of 5.7. Maximum activity was obtained at 55 degrees C and pH 8.5. The activity of GLDH at 4 and 20 degrees C was 38 and 50%, respectively, of that at 50 degrees C. GLDH was coupled to cytochrome c and several redox dyes including 1-methoxy-5-methylphenazinium methylsulfate (1-Methoxy PMS), 2, 6-dichlorophenylindophenol (DCIP), 9-dimethylaminobenzo[alpha]phenoxazin-7-ium chloride (meldola's blue), 3,3'-[3,3'-dimethoxy-(1,1'-biphenyl)-4, 4'-diyl]-bis[2-(4-nitrophenyl)-5-phenyl-2H tetrazolium chloride] (nitroblue tetrazolium; NBT), and 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H tetrazolium (INT). The presence of NAD(P) and oxygen gave no oxidation activity to GLDH. Spectroscopic profile and ICP data indicated a b-type cytochrome containing iron.
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PMID:Purification and characterization of cold-active L-glutamate dehydrogenase independent of NAD(P) and oxygen. 1010 Dec 90

Allergic rhinitis, a frequently occurring immunological disorder affecting men, women and children worldwide, is a state of hypersensitivity that occurs when the body overreacts to a substance such as pollen, mold, mites or dust. Allergic rhinitis exerts inflammatory response and irritation of the nasal mucosal membranes leading to sneezing; stuffy/runny nose; nasal congestion; and itchy, watery and swollen eyes. A novel, safe polyherbal formulation (Aller-7/NR-A2) has been developed for the treatment of allergic rhinitis using a unique combination of extracts from seven medicinal plants including Phyllanthus emblica, Terminalia chebula, Terminalia bellerica, Albizia lebbeck, Piper nigrum, Zingiber officinale and Piper longum. In this study, the antioxidant efficacy of Aller-7 was investigated by various assays including hydroxyl radical scavenging assay, superoxide anion scavenging assay, 1,1-diphenyl-2-picryl hydrazyl (DPPH) and 2,2-azinobis-ethyl-benzothiozoline-sulphonic acid diammonium salt (ABTS) radical scavenging assays. The protective effect of Aller-7 on free radical-induced lysis of red blood cells and inhibition of nitric oxide release by Aller-7 in lipopolysaccharide-stimulated murine macrophages were determined. Aller-7 exhibited concentration-dependent scavenging activities toward biochemically generated hydroxyl radicals (IC50 741.73 microg/ml); superoxide anion (IC50 24.65 microg/ml by phenazine methosulfate-nicotinamide adenine dinucleotide [PMS-NADH] assay and IC50 4.27 microg/ml by riboflavin/nitroblue tetrazolium [NBT] light assay), nitric oxide (IC50 16.34 microg/ml); 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical (IC50 5.62 microg/ml); and 2,2-azinobis-ethyl-benzothiozoline-sulphonic acid diammonium salt (ABTS) radical (IC50 7.35 microg/ml). Aller-7 inhibited free radical-induced hemolysis in the concentration range of 20-80 microg/ml. Aller-7 also significantly inhibited nitric oxide release from lipopolysaccharide-stimulated murine macrophages. These results demonstrate that Aller-7 is a potent scavenger of free radicals and that it may serve.
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PMID:Antioxidant properties of Aller-7, a novel polyherbal formulation for allergic rhinitis. 1536 86

The present study was carried out to evaluate the antioxidant and antimicrobial activities of a methanol extract of Bauhinia racemosa (MEBR) (Caesalpiniaceae) stem bark in various systems. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. The antioxidant activity of the methanol extract increased in a concentration-dependent manner. About 50, 100, 250, and 500 microg MEBR inhibited the peroxidation of a linoleic acid emulsion by 62.43, 67.21, 71.04, and 76.83%, respectively. Similarly, the effect of MEBR on reducing power increased in a concentration-dependent manner. In DPPH radical scavenging assays the IC50 value of the extract was 152.29 microg/ml. MEBR inhibited the nitric oxide radicals generated from sodium nitroprusside with an IC50 of 78.34 microg/ml, as opposed to 20.4 microg/ml for curcumin. Moreover, MEBR scavenged the superoxide generated by the PMS/NADH-NBT system. MEBR also inhibited the hydroxyl radical generated by Fenton's reaction, with an IC50 value of more than 1000 microg/ml, as compared to 5 microg/ml for catechin. The amounts of total phenolic compounds were also determined and 64.7 microg pyrocatechol phenol equivalents were detected in MEBR (1 mg). The antimicrobial activities of MEBR were determined by disc diffusion with five Gram-positive, four Gram-negative and four fungal species. MEBR showed broad-spectrum antimicrobial activity against all tested microorganisms. The results obtained in the present study indicate that MEBR can be a potential source of natural antioxidant and antimicrobial agents.
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PMID:Antioxidant and antimicrobial activities of Bauhinia racemosa L. stem bark. 1600 72

In this study we investigated the superoxide radicals scavenging effect and xanthine oxidase inhibitory activity by magnesium lithospermate B, which was originally isolated from the roots of Salvia miltiorrhiza (also named Danshen or Dansham), an important herb in Oriental medicine. Superoxide radicals were generated both in beta-NADH/PMS system and xanthine/ xanthine oxidase system. Magnesium lithospermate B significantly inhibited the reduction of NBT induced by superoxide radicals with an IC(50) of 29.8 microg/mL and 4.06 microg/mL respectively in the two systems. Further study suggested that magnesium lithospermate B can directly inhibit xanthine oxidase and exhibits competitive inhibition. Magnesium lithospermate B was also found to have the hypouricemic activity in vivo against potassium oxonate-induced hyperuricaemia in mice. After oral administration of magnesium lithospermate B at doses of 10, 20 and 30 mg/kg, there was a significant decrease in the serum urate level when compared to the hyperuricemia control. In addition, magnesium lithospermate B significantly protected HL-60 cells from superoxide radicals-induced apoptosis in the xanthine/ xanthine oxidase reactions. This study provided evidence that magnesium lithospermate B exhibits direct superoxide radicals scavenging and xanthine oxidase inhibitory activity.
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PMID:Superoxide radicals scavenging and xanthine oxidase inhibitory activity of magnesium lithospermate B from Salvia miltiorrhiza. 1868 36


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