Related Experiment Video
Updated: Aug 14, 2026

Spectrophotometric Screening for Potential Inhibitors of Cytosolic Glutathione S-Transferases
Published on: October 10, 2020
Glutathione S-transferase M1 polymorphism and metabolism of sulforaphane from standard and high-glucosinolate
Amy V Gasper1, Ahmed Al-Janobi, Julie A Smith
1Phytochemicals and Health Programme, Institute of Food Research, Norwich Research Park, Colney, Norwich, United Kingdom.
Background:
Broccoli consumption is associated with a reduction in the risk of cancer, particularly in persons with a functional glutathione S-transferase M1 allele, as opposed rotrose whose GSTM1 gene has been deleted. Sulforaphane, the major isothiocyanate derived from 4-methylsulfinylbutyl glucosinolate, is thought to be the main agent conferring protection.
Objective:
We compared sulforaphane metabolism in GSTM1-null and GSTM1-positive subjects after they consumed standard broccoli and high-glucosinolate broccoli (super broccoli).
Design:
Sixteen subjects were recruited into a randomized, 3-phase crossover dietary trial of standard broccoli, super broccoli, and water. Liquid chromatography linked to tandem mass spectrometry was used to quantify sulforaphane and its thiol conjugates in plasma and urine.
Results:
GSTM1-null subjects had slightly higher, but statistically significant, areas under the curve for sulforaphane metabolite concentrations in plasma, a greater rate of urinary excretion of sulforaphane metabolites during the first 6 h after broccoli consumption, and a higher percentage of sulforaphane excretion 24 h after ingestion than did GSTM1-positive subjects. Consumption of high-glucosinolate broccoli led to a 3-fold greater increase in the areas under the curve and maximum concentrations of sulforaphane metabolites in plasma, a greater rate of urinary excretion of sulforaphane metabolites during the first 6 h after consumption, and a lower percentage of sulforaphane excretion after its ingestion than did the consumption of standard broccoli.
Conclusions:
GSTM1 genotypes have a significant effect on the metabolism of sulforaphane derived from standard or high-glucosinolate broccoli. It is possible that the difference in metabolism may explain the greater protection that GSTM1-positive persons gain from consuming broccoli. The potential consequences of consuming glucosinolate-enriched broccoli for GSTM1-null and -positive persons are discussed.
More Related Videos
Related Concept Videos
Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Phase II Reactions: Glutathione Conjugation and Mercapturic Acid Formation
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Sulfur Assimilation
Drug Metabolism: Phase II Reactions
Pharmacogenetics of Drug Transporters: P-Glycoprotein and Solute Carrier Transporters

