Combet, E., Elmesmari, A., Preston, T., Crozier, A. and McColl, K.E.L. (2010) Dietary phenolic acids and ascorbic acid: influence on acid-catalyzed nitrosative chemistry in the presence and absence of lipids. Free Radical Biology and Medicine, 48(6), pp. 763-771. (doi: 10.1016/j.freeradbiomed.2009.12.011)
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Abstract
Acid-catalyzed nitrosation and production of potentially carcinogenic nitrosative species is focused at the gastroesophageal junction, where salivary nitrite, derived from dietary nitrate, encounters the gastric juice. Ascorbic acid provides protection by converting nitrosative species to nitric oxide (NO). However, NO may diffuse into adjacent lipid, where it reacts with O2 to re-form nitrosative species and N-nitrosocompounds (NOC). In this way, ascorbic acid promotes acid nitrosation. Using a novel benchtop model representing the gastroesophageal junction, this study aimed to clarify the action of a range of water-soluble antioxidants on the nitrosative mechanisms in the presence or absence of lipids. Caffeic, ferulic, gallic, or chlorogenic and ascorbic acids were added individually to simulated gastric juice containing secondary amines, with or without lipid. NO and O2 levels were monitored by electrochemical detection. NOC were measured in both aqueous and lipid phases by gas chromatography-tandem mass spectrometry. In the absence of lipids, all antioxidants tested inhibited nitrosation, ranging from 35.9 Ý 7.4% with gallic acid to 93 Ý 0.6% with ferulic acid. In the presence of lipids, the impact of each antioxidant on nitrosation was inversely correlated with the levels of NO they generated (R2 = 0.95, p < 0.01): gallic, chlorogenic, and ascorbic acid promoted nitrosation, whereas ferulic and caffeic acids markedly inhibited nitrosation.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Preston, Professor Tom and Elmesmari, Dr Aziza and McColl, Professor Kenneth and Combet Aspray, Professor Emilie and Crozier, Professor Alan |
| Authors: | Combet, E., Elmesmari, A., Preston, T., Crozier, A., and McColl, K.E.L. |
| Subjects: | Q Science > QH Natural history > QH345 Biochemistry |
| College/School: | College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing > Clinical Specialities College of Science and Engineering > Scottish Universities Environmental Research Centre College of Medical Veterinary and Life Sciences > School of Infection & Immunity |
| Journal Name: | Free Radical Biology and Medicine |
| ISSN: | 0891-5849 |
| ISSN (Online): | 1873-4596 |
| Published Online: | 21 December 2009 |
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