Tobacco-specific and betel nut-specific N-nitroso compounds: occurrence in saliva and urine of betel quid chewers and formation in vitro by nitrosation of betel quid

Abstract

In order to evaluate exposure of betel quid chewers to N-nitroso compounds, saliva and urine samples were collected from chewers of betel quid with or without tobacco, from tobacco chewers, from cigarette smokers and from people with no such habit, and were analysed for the presence of N-nitrosamines by gas chromatography coupled with Thermal Energy Analyzer and alkaloids derived from betel nut and tobacco by capillary gas chromatography fitted with nitrogen-phosphorous selective detector. The levels of the betel nut-specific nitrosamines, N-nitrosoguvacoline and N-nitrososoguvacine (the latter being detected for the first time in saliva), ranged from 0 to 7.1 and 0 to 30.4 ng/ml, respectively. High levels of tobacco-specific nitrosamines were detected in the saliva of chewers of betel quid with tobacco and in that of chewers of tobacco, ranging from 1.6 to 59.7 (N'-nitrosonornicotine), 1.0 to 51.7 (N'-nitrosoanatabine) and 0 to 2.3 [4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone] ng/ml. Urinary concentrations of certain N-nitrosamino acids, including N-nitrosoproline, were determined as a possible index of exposure to nitroso compounds and their precursors in the study groups: no clear difference was observed. The betel nut-specific alkaloid, arecoline, was present at high levels in the saliva of betel quid chewers with or without tobacco. Nicotine and cotinine were also detected in saliva and urine of chewers of tobacco and of betel quid with tobacco. In order to assess whether N-nitroso compounds are formed in vivo in the oral cavity during chewing or in the stomach after swallowing the quids, the levels of N-nitroso compounds in betel quid extracts were determined before and after nitrosation at pH 7.4 and 2.1. The results indicate that N-nitroso compounds could easily be formed in vivo. The possible role of N-nitroso compounds in the causation of cancer of the upper alimentary tract in betel quid chewers is discussed.

Analysis of Tobacco-Specific Nitrosamines in the Common Smokeless Tobacco Afzal in Oman

“…4 While nitrosamines are present in many foods and items which come into contact with food in amounts ranging from 1-10 ng/g, the highest exposure to humans comes from tobacco use. 17 These chemical compounds have been detected in the saliva of tobacco chewers and are believed to form in the digestive system. 17 All STPs demonstrate a wide diversity in their chemical compositions which result from variations in geographical location, additives used and manufacturing methods.…”

“…17 These chemical compounds have been detected in the saliva of tobacco chewers and are believed to form in the digestive system. 17 All STPs demonstrate a wide diversity in their chemical compositions which result from variations in geographical location, additives used and manufacturing methods. 4 In order to avoid potentially diverse chemical compositions, one random sample of Afzal was chosen to conduct several chemical and toxicological tests.…”

Up-regulation of Inflammatory Signalings by Areca Nut Extract and Role ofCyclooxygenase-2−1195G>A Polymorphism Reveal Risk of Oral Cancer

“…Cancer Res 2008; 68: (20). October 15, 2008 800 Ag/mL of both extracts) were used to assess the level of gene coexpressions between upstream effectors and COX-2 by the Pearson's and Spearman's correlation coefficients.…”

“…The cytotoxic effect of saliva-reacted ANE (sANE) was also investigated because saliva catalyzes the ingredients of areca nut (AN) into derived nitrosamines, such as 3-(methylnitrosamino)propionitrile (MNPN) and N-nitrosoguvacoline (NGL; refs. 19,20). By this approach, we could further characterize the upstream regulators significantly involved in AN-induced COX-2 expression and possibly in risk of betelrelated OSCC.…”

Association of Cytochrome P450 with Cancer Induced by Betel Quid (BQ): A Review

“…Chewing of tobacco with BQ results in high exposure to carcinogenic tobacco-specific nitrosamines (TSNAs), to ~1000 mg/day 88 , compared with ~20 mg/day in smokers 89 , as well as leading to exposure to nitrosamines derived from areca nut alkaloids. The carcinogenic TSNAs N'-nitrosonornicotine (NNN), 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and Nnitrosoanabasine (NAB), as well as the volatile nitrosamines N-nitrosodimethylamine and N-nitrosodiethylamine, have been detected in the saliva of chewers of BQ with tobacco [90][91][92][93] .…”