Glucobrassicin → I3C
Sulfur compounds
The other great glucosinolate of cabbages, the one that gives indole-3-carbinol.
It dominates in head cabbages where glucoraphanin dominates in broccoli: two crucifers are not interchangeable.
Effects and benefits
The other great treasure of head cabbages. In the stomach, its indole-3-carbinol condenses into DIM, which changes how the liver processes estrogens; and its derivatives activate a gut receptor that maintains the barrier of the gut wall, as shown in mice.
Like the glucoraphanin of broccoli, glucobrassicin waits for the cabbage to be chewed to meet its enzyme. It then releases indole-3-carbinol, unstable, which condenses in stomach acid into diindolylmethane, DIM.
In humans, these molecules steer the liver toward one pathway of estrogen processing rather than another; trials have measured it in urine, with cabbages or indole-3-carbinol supplements (Michnovicz et al., 1997). What this changes for health is still being studied.
In mice, cabbage derivatives activate a receptor on the immune cells of the gut, AhR; deprived of these molecules, mice lose part of the defenses of their gut wall (Li et al., 2011).
Sources: Michnovicz et al., JNCI, 1997 · Li et al., Cell, 2011