TITLE

Fat transforms ascorbic acid from inhibiting to promoting acid-catalysed N-nitrosation

AUTHOR(S)
Combet, E.; Paterson, S.; Lijima, K.; Winter, J.; Mullen, W.; Crozier, A.; Preston, T.; McColl, K. E. L.
PUB. DATE
December 2007
SOURCE
Gut;Dec2007, Vol. 56 Issue 12, p1678
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Background: The major potential site of acid nitrosation is the proximal stomach, an anatomical site prone to a rising incidence of metaplasia and adenocarcinoma. Nitrite, a pre-carcinogen present in saliva, can be converted to nitrosating species and N-nitroso compounds by acidification at low gastric pH in the presence of thiocyanate. Aims: To assess the effect of lipid and ascorbic acid on the nitrosative chemistry under conditions simulating the human proximal stomach. Methods: The nitrosative chemistry was modelled in vitro by measuring the nitrosation of four secondary amines under conditions simulating the proximal stomach. The N-nitrosamines formed were measured by gas chromatography-ion-trap tandem mass spectrometry, while nitric oxide and oxygen levels were measured amperometrically. Results: In absence of lipid, nitrosative stress was inhibited by ascorbic acid through conversion of nitrosating species to nitric oxide. Addition of ascorbic acid reduced the amount of N-nitrosodimethylamine formed by fivefold, N-nitrosomorpholine by >1000-fold, and totally prevented the formation of N-nitrosodiethylamine and N-nitrosopiperidine. In contrast, when 10% lipid was present, ascorbic acid increased the amount of N-nitrosodimethylamine, N-nitrosodiethylamine and N-nitrosopiperidine formed by approximately 8-, 60- and 140-fold, respectively, compared with absence of ascorbic acid. Conclusion: The presence of lipid converts ascorbic acid from inhibiting to promoting acid nitrosation. This may be explained by nitric oxide, formed by ascorbic acid in the aqueous phase, being able to regenerate nitrosating species by reacting with oxygen in the lipid phase.
ACCESSION #
28105570

 

Related Articles

  • Nitrate and nitrosative chemistry within Barrett's oesophagus during acid reflux. Suzuki, H.; Iijima, K.; Scobie, G.; Fyfe, V.; McColl, K. E. L. // Gut;Nov2005, Vol. 54 Issue 11, p1527 

    Background and aims: When saliva, with its high nitrite content derived from the enterosalivary recirculation of dietary nitrate, meets acidic gastric juice, the nitrite is converted to nitrous acid, nitrosative species, and nitric oxide. In healthy volunteers this potentially mutagenic...

  • Effects of Ascorbic Acid Treatment to Grapevine Rootstock-1616C and Vitis vinifera L. cvs. Razaki. Yildirim, Özlem // Asian Journal of Biochemistry;2007, Vol. 2 Issue 6, p395 

    The glutathione contents, ascorbic acid, nitric oxide, lipid peroxide levels and the activities of free radical scavenging enzymes were examined using five different concentrations of ascorbic acid treated Razakı cultivar and 1616C rootstock. Reduced glutathione was increased with ascorbic...

  • EPC-K1 PROTECTS NEURONAL CELLS FROM PEROXYNITRITE-MEDIATED OXIDATIVE DAMAGE. Wei, Taotao; Xin, Wenjuan; Hou, Jingwu; Chen, Chang; Mori, Akitane // Research on Chemical Intermediates;2000, Vol. 26 Issue 7/8, p667 

    Presents a study which examined the protective effects of EPC-K1 on neuronal cell damage mediated by peroxynitrite using primary culture of rat cerebellar granule cells as a model. Overview of nitric oxide; Experimental procedure; Results and discussion.

  • Another Reason to Eat Your Vegetables--Nitric Oxide.  // Consumers' Research Magazine;Feb2000, Vol. 83 Issue 2, p41 

    Reports on the health benefits of nitric oxide (NO). How the nitrates found in the food are converted into nitrites; Examples of studies on nitric oxide.

  • Nitrite content and antioxidant enzyme levels in the blood of schizophrenia patients. Srivastava, Nupur; Barthwal, Manoj K.; Dalal, Pranob K.; Agarwal, Anil K.; Nag, Devika; Srimal, Rikhab C.; Seth, Prahlad K.; Dikshit, Madhu // Psychopharmacology;2001, Vol. 158 Issue 2, p140 

    Rationale: Recent studies have suggested augmentation in the inflammatory response as well as involvement of nitric oxide (NO) in mood disorders. Polymorphonuclear leukocytes (PMN), NO and free radicals have been associated with inflammatory response; however, the status of NO in the PMN has not...

  • Inflammation-induced endothelial dysfunction involves reduced nitric oxide bioavailability and increased oxidant stress Clapp, Brian R.; Hingorani, Aroon D.; Kharbanda, Rajesh K.; Mohamed-Ali, Vidya; Stephens, Jeffrey W.; Vallance, Patrick; MacAllister, Raymond J. // Cardiovascular Research;Oct2004, Vol. 64 Issue 1, p172 

    Our aim was to investigate mechanisms of inflammation-induced endothelial dysfunction in humans.Endothelial function in twenty-one healthy human volunteers was measured using forearm venous plethysmography before and 8 h after administration of typhoid vaccination to generate an inflammatory...

  • VITAMIN C FOR BOOSTING NO.  // Muscle & Performance;Mar2012, Vol. 4 Issue 3, p12 

    The article recommends the intake of vitamin C together with arginine and other pre-workout supplements to boost immunity and to combat free radicals which break down nitric oxide.

  • Nitrosative Stress as a Mediator of Apoptosis: Implications for Cancer Therapy. Hirst, David G.; Robson, Tracy // Current Pharmaceutical Design;1/1/2010, Vol. 16 Issue 1, p45 

    Nitric oxide (NO·) is now recognised as one of the most important molecules influencing the development, progression and treatment of cancer. A key component of its action is as a negative and positive regulator of apoptosis. Broadly, constitutive levels of NO· (nM), are capable of...

  • Effect of asymmetric dimethylarginine on osteoblastic differentiation. Xiao, Z. Sheng; Quarles, L. Darryl; Chen, Q. Quan; Yu, Y. Hui; Qu, X. Ping; Jiang, C. Hong; Deng, H. Wu; Li, Y. Jian; Zhou, H. Hao; Xiao, Z S; Quarles, L D; Chen, Q Q; Yu, Y H; Qu, X P; Jiang, C H; Deng, H W; Li, Y J; Zhou, H H // Kidney International;Nov2001, Vol. 60 Issue 5, p1699 

    Background: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS) that accumulates in renal insufficiency and may be a uremic toxin. To determine whether ADMA inhibits bone metabolism, we investigated the in vitro effect of ADMA on osteoblastic...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sign out of this library

Other Topics