Effects of glucosinolate-rich broccoli sprouts on urinary levels of aflatoxin-DNA adducts and phenanthrene tetraols in a randomized clinical trial in He Zuo township, Qidong, People's Republic of China

Cancer Epidemiol Biomarkers Prev. 2005 Nov;14(11 Pt 1):2605-13. doi: 10.1158/1055-9965.EPI-05-0368.


Residents of Qidong, People's Republic of China, are at high risk for development of hepatocellular carcinoma, in part due to consumption of aflatoxin-contaminated foods, and are exposed to high levels of phenanthrene, a sentinel of hydrocarbon air toxics. Cruciferous vegetables, such as broccoli, contain anticarcinogens. Glucoraphanin, the principal glucosinolate in broccoli sprouts, can be hydrolyzed by gut microflora to sulforaphane, a potent inducer of carcinogen detoxication enzymes. In a randomized, placebo-controlled chemoprevention trial, we tested whether drinking hot water infusions of 3-day-old broccoli sprouts, containing defined concentrations of glucosinolates, could alter the disposition of aflatoxin and phenanthrene. Two hundred healthy adults drank infusions containing either 400 or < 3 micromol glucoraphanin nightly for 2 weeks. Adherence to the study protocol was outstanding; no problems with safety or tolerance were noted. Urinary levels of aflatoxin-N(7)-guanine were not different between the two intervention arms (P = 0.68). However, measurement of urinary levels of dithiocarbamates (sulforaphane metabolites) indicated striking interindividual differences in bioavailability. An inverse association was observed for excretion of dithiocarbamates and aflatoxin-DNA adducts (P = 0.002; R = 0.31) in individuals receiving broccoli sprout glucosinolates. Moreover, trans, anti-phenanthrene tetraol, a metabolite of the combustion product phenanthrene, was detected in urine of all participants and showed a robust inverse association with dithiocarbamate levels (P = 0.0001; R = 0.39), although again no overall difference between intervention arms was observed (P = 0.29). Understanding factors influencing glucosinolate hydrolysis and bioavailability will be required for optimal use of broccoli sprouts in human interventions.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aflatoxins / metabolism
  • Aflatoxins / urine*
  • Aged
  • Anticarcinogenic Agents / pharmacology*
  • Beverages
  • Biological Availability
  • Brassica / chemistry*
  • Carcinoma, Hepatocellular / etiology
  • Carcinoma, Hepatocellular / prevention & control
  • DNA Adducts / urine*
  • Female
  • Glucosinolates / pharmacology*
  • Humans
  • Hydrolysis
  • Liver Neoplasms / etiology
  • Liver Neoplasms / prevention & control
  • Male
  • Middle Aged
  • Phenanthrenes / urine*
  • Placebos


  • Aflatoxins
  • Anticarcinogenic Agents
  • DNA Adducts
  • Glucosinolates
  • Phenanthrenes
  • Placebos