Cruciferous vegetables contain high levels of the sulphur containing phytochemical sulforaphane. Other studies have suggested that consumption of cruciferous vegetables, and especially broccoli may lower the prostate cancer risk. Prostate cancer is the second leading cause of male cancer deaths in the United States. Prostate cancer is characterized by the loss of phase-2-enzyme (a glutathione transferase) thereby reducing the ability of the prostate cells to neutralize carcinogens. During early prostate carcinogenesis the DNA of prostate cells is damaged by methylation of deoxycytidine residues. The universal production of phase-2-enzymes could reduce the risk of prostate cancer. The aim of this study was to investigate the effect of sulforaphane consumption and prostate cancer risk. The isothiocyanate sulforaphane is the most powerful phase-2-enzyme inducing phytochemicals known to date.
Tests were carried out on different human prostate cell lines with pure sulforaphane and with extracts from broccoli sprouts. To estimate the phase-2-enzyme activity the marker QR was measured.
Sulforaphane increased levels of reduced glutathione thereby boosting the reductive capacity of the prostate cell. In all 5 prostate cancer cell lines tested, sulforaphane increased phase-2-enzyme activation. The investigators concluded that sulforaphane is a potent inducer of phase-2-enzymes in human prostate cells. The exact mechanism by which sulforaphane acts on prostate cancer cells is still unclear and more studies are required.
Source: James D. Brook, Vincent G. Paton and Genevieve Vidanes. Potent induction of phase-2-enzymes in human prostate cells by sulforaphane.. Cancer Epidemiology Biomarkers and Prevention, Vol. 10, 949-954, September 2001