In vitro acetaldehyde formation by human colonic bacteria.
Open Access
- 1 September 1994
- Vol. 35 (9) , 1271-1274
- https://doi.org/10.1136/gut.35.9.1271
Abstract
Incubation of human colonic contents with various ethanol concentrations (2.75-44 mM) in vitro at 37 degrees C resulted in significant accumulation of acetaldehyde--a toxic and highly reactive compound. At pH 9.6, all samples produced notable acetaldehyde concentrations (58 (13) microM; mean (SEM)) even from the lowest (2.75 mM) ethanol concentration, and the production of acetaldehyde increased lin-early with rising ethanol concentration (r = 0.97; p < 0.005), reaching a peak concentration of 238 (37) microM at 44 mM ethanol. The formation of acetaldehyde took place rapidly, as almost 50% of acetaldehyde formed during the total eight hour incubation was detectable after one hour, and 75% of the total after four hours. Maximal acetaldehyde production from 22 mM ethanol occurred at pH 9.6 (160 (35) microM) but appreciable concentrations were also seen at pH 7.4 (110 (38) microM) and pH 6.0 (63 (19) microM). At pH 4.0, by contrast, acetaldehyde formation was negligible (17 (5) microM). 4-Methylpyrazole, a potent inhibitor of alcohol dehydrogenase, showed a decreasing effect on acetaldehyde production in vitro but first at a concentration of 100 mM. Considerable acetaldehyde production by human colonic bacteria--if it occurs also in vivo--could constitute a risk factor for rectal cancer in heavy drinkers and also provide a pathogenetic mechanism for alcohol induced diarrhoea.Keywords
This publication has 40 references indexed in Scilit:
- Purification and Characterization of Helicobacter pylori Alcohol DehydrogenaseAlcohol, Clinical and Experimental Research, 1994
- Diet and colorectal cancer with special reference to fiber intakeInternational Journal of Cancer, 1989
- Detection of a protein-acetaldehyde adduct in the liver of rats fed alcohol chronically.Journal of Clinical Investigation, 1988
- The detection of acetaldehyde/liver plasma membrane protein adduct formed in vivo by alcohol feedingLiver International, 1987
- Antibodies against acetaldehyde-modified protein epitopes in human alcoholicsHepatology, 1987
- First pass metabolism of ethanol - A gastrointestinal barrier against the systematic toxicity of ethanolLife Sciences, 1985
- Prospective Study of Alcohol Consumption and CancerNew England Journal of Medicine, 1984
- Alcohol Inhibition of Rectosigmoid Motility in HumansDigestion, 1981
- The role of alcohol and tobacco in multiple primary cancers of the upper digestive system, larynx and lung: A prospective studyPreventive Medicine, 1974
- Cancer of the gastrointestinal tract. Etiological and environmental factorsPublished by American Medical Association (AMA) ,1973