Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor that regulates the cell's defense against oxidative stress and other insults: 

    Antioxidant defense: NRF2 is a master regulator of the antioxidant response elements (ARE), which helps protect cells from damage. 

Drug detoxification: NRF2 helps the body detoxify drugs and other xenobiotics. 
Cellular processes: NRF2 regulates many other cellular processes, including metabolism, inflammation, and DNA repair. 
Stress response: NRF2 is a critical regulator of cellular health, especially during stress. 

NRF2 is the body's first line of defense against oxidative stress and can help protect against many diseases, including:

    Cancer
    Cardiovascular disease
    Chronic obstructive pulmonary disease
    Drug toxicity
    Inflammation
    Neurodegenerative disease
    Stress-induced diseases 

However, NRF2 can also play a pathogenic role, depending on when and how long it's activated. For example, some evidence suggests that NRF2 can contribute to heart failure. 
Sulforaphane, a compound found in cruciferous vegetables like broccoli, bok choy, and Brussels sprouts, is a potent activator of NRF2



How long does it take for Nrf2 to work?
It takes less than fifteen minutes from the time of exposure to switch on nuclear import of Nrf2. This is followed by activation of a delayed mechanism that controls switching off of Nrf2 activation of gene expression. GSK3β phosphorylates Fyn at unknown threonine residue(s) leading to nuclear localization of Fyn.