Quantitation of human uptake of the anticarcinogen phenethyl isothiocyanate after a watercress meal.
Our previous studies showed that phenethyl isothiocyanate (PEITC), a cruciferous vegetable constituent, inhibited the lung tumorigenesis induced by a potent tobacco-specific carcinogenic nitrosamine in animals. These results implicate dietary PEITC as a risk-reducing factor of lung cancers induced by smoking. To define the effect of dietary PEITC on human cancers, a method of measuring its uptake is needed. Since watercress is rich in gluconasturtiin, a glucosinolate precursor of PEITC, it was chosen to be the source of PEITC. Four individuals were asked to eat watercress as part of a breakfast meal, and 24-h urine samples were collected. A urinary metabolite was found, and its identity was confirmed as the N-acetylcysteine conjugate of PEITC by comparison with the synthetic standard using nuclear magnetic resonance and mass spectrometry. A dose-dependent excretion of this conjugate was observed. These results clearly showed that PEITC was released in the human body upon ingestion of watercress and suggest that the N-acetylcysteine conjugate of PEITC may be a useful marker for quantitating human exposure to this anticarcinogen as a tool for epidemiological investigations.
Chung
F L
FL
Division of Chemical Carcinogenesis, American Health Foundation, Valhalla, New York 10595.
Morse
M A
MA
Eklind
K I
KI
Lewis
J
J
D000818:Animals; D016588:Anticarcinogenic Agents / Q000378:metabolism / Q000493:pharmacokinetics / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards; D004305:Dose-Response Relationship, Drug; D004435:Eating; D005069:Evaluation Studies as Topic; D005260:Female; D005961:Glucosinolates / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D017879:Isothiocyanates; D008175:Lung Neoplasms / Q000178:diet therapy / Q000517:prevention & control; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D008657:Metabolic Clearance Rate; D051379:Mice; D013861:Thiocyanates / Q000378:metabolism / Q000493:pharmacokinetics / Q000652:urine*; D014675:Vegetables
D016588:Anticarcinogenic Agents; D005961:Glucosinolates; D017879:Isothiocyanates; D013861:Thiocyanates; C058305:phenethyl isothiocyanate