Sulforaphane slows down phase I detoxification and speeds up phase II detoxification.
"And so sulforaphane slows down phase one and then speeds up phase two so you don't get that detox flu" (said at 0:22:36)
Preclinical cell and animal studies support the premise that sulforaphane can inhibit certain Phase I cytochrome P450 enzymes (such as CYP3A4 and CYP2E1) and induce Phase II detoxification enzymes (such as glutathione S-transferases and NQO1 via the Nrf2 pathway). However, this effect is isozyme-specific rather than a universal suppression of all Phase I enzymes, and some models demonstrate induction of specific CYPs such as CYP1A1. Furthermore, there is no clinical evidence linking this enzymatic modulation to the prevention of 'detox flu', a colloquial naturopathic concept with no established medical definition.
- supports: Cruciferous vegetables: cancer protective mechanisms of glucosinolate hydrolysis products … (Integrative cancer therapies 2004)
"These mechanisms include altered estrogen metabolism, protection against reactive oxygen species, altered detoxification by induction of phase II enzymes, decreased carcinogen activation by inhibition of phase I enzymes, and slowed tumor growth and induction of apoptosis." (abstract, passage verified)
pubmedfull study (doi) - context: Sulforaphane induces CYP1A1 mRNA, protein, and catalytic activity levels via an AhR-depend… (Cancer letters 2009)
"This is the first demonstration that the broccoli-derived SUL can directly induce Cyp1a1 gene expression in an AhR-dependent manner and represents a novel mechanism by which SUL induces this enzyme." (abstract, results, passage verified)
pubmedfull study (doi) - supports: Inhibition of cytochromes P-450 and induction of glutathione S-transferases by sulforaphan… (Cancer research 1997)
"In SF-treated human hepatocytes, hGSTA1/2 but not hGSTM1 mRNAs were induced, and the expression of CYP1A2 was unaffected, whereas the expression of CYP3A4, the major CYP in human liver, was markedly decreased at both mRNA and activity levels. These observations demonstrate that in intact human and rat hepatocytes, SF may both induce a number of GSTs and cause enzyme inhibition of some but not all CYPs and, in the case of CYP3A4, inhibit both its enzyme activity and its expression." (abstract, results, passage verified)
pubmed