title: Fecal and urinary excretion of aflatoxin B1 metabolites (AFQ1, AFM1 and AFB-N7-guanine) in young Chinese males.
abstract: Our study was designed to assess the fecal and urinary excretion of 3 aflatoxin B1 (AFB1) metabolites, aflatoxins M1 (AFM1) and Q1 (AFQ1) and aflatoxin B1-N7-guanine (AFB-N7-guanine) that are produced by the predominant forms of cytochrome P450 enzymes responsible for the biotransformation of AFB1. Fecal and urinary AFM1, AFQ1 and urinary AFB-N7-guanine were assessed in 83 young Chinese males selected from a larger population (n = 300) based on detectable urinary AFM1. The concentration of fecal AFQ1 (median 137 ng/g fresh weight, IQR 9.1 to 450) was approximately 60 times higher than that of AFM1 (2.3 ng/g, IQR 0.0 to 7.3). In urine, the median AFQ1 was 10.4 ng/ml (IQR 3.4 to 23.3), and the median AFM1 and AFB-N7-guanine 0.04 ng/ml (IQR 0.01 to 0.33) and 0.38 ng/ml (IQR 0.0 to 2.15), respectively. A subgroup (n = 14) with hepatitis B virus (HBV) infection had significantly higher fecal concentrations of AFQ1 (p = 0.043) and AFM1 (p = 0.001) than those who were hepatitis B-virus antigen (HBsAg) negative, and the respective differences in urinary AFQ1 and AFM1 concentrations approached statistical significance (p = 0.054, p = 0.138). Our study demonstrates that AFQ1 is excreted in urine and feces at higher levels than AFM1, and feces are an important route of excretion of these AFB1 metabolites. AFQ1 should be further assessed for its predictive value as a marker for exposure and risk of dietary aflatoxins.
authors.affiliation: Department of Clinical Nutrition and Food and Health Research Centre, University of Kuopio, Kuopio, Finland. hannu.mykkanen@uku.fi
authors.forename: Hannu
authors.initials: H
authors.lastname: Mykkänen
authors.forename: Huilian
authors.initials: H
authors.lastname: Zhu
authors.forename: Eeva
authors.initials: E
authors.lastname: Salminen
authors.forename: Risto Olavi
authors.initials: RO
authors.lastname: Juvonen
authors.forename: Wenhua
authors.initials: W
authors.lastname: Ling
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.forename: Nektaria
authors.initials: N
authors.lastname: Polychronaki
authors.forename: Heidi
authors.initials: H
authors.lastname: Kemiläinen
authors.forename: Otto
authors.initials: O
authors.lastname: Mykkänen
authors.forename: Seppo
authors.initials: S
authors.lastname: Salminen
authors.forename: Hani
authors.initials: H
authors.lastname: El-Nezami
mesh_terms: D016604:Aflatoxin B1 / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000652:urine*; D016607:Aflatoxin M1 / Q000652:urine; D000348:Aflatoxins / Q000652:urine; D002681:China; D005243:Feces / Q000737:chemistry; D006147:Guanine / Q000031:analogs & derivatives* / Q000652:urine; D006509:Hepatitis B / Q000150:complications / Q000652:urine; D006801:Humans; D008297:Male
chemical_list: D000348:Aflatoxins; C033759:aflatoxin Q1; D006147:Guanine; C028319:2,3-dihydro-2-(N(7)-guanyl)-3-hydroxyaflatoxin B1; D016607:Aflatoxin M1; D016604:Aflatoxin B1