CYP1A1 is one of the cytochrome P450 monooxygenases (CYPs). These are enzymes that help eliminate most of the drugs and toxins from the human body .
CYP1A1 Function (Drug Metabolism)
- polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene . PAHs are a group of more than 100 different chemicals that are released from burning coal, oil, gasoline, trash, tobacco, wood, or charcoal-broiled meat.
- estrogen [2, 3].
When CYP1A1 processes PAHs, it can activate them as cancer-causing agents .
Unlike most other CYP enzymes, this one is mainly found outside of the liver, in tissues such as the lungs .
CYP1A1 the Good
CYP1A1 is important for the removal of toxic chemicals from our organism. Mice lacking this enzyme die within 30 days of benzo[a]pyrene treatment, whereas normal mice survive with no signs of toxicity .
Although this enzyme can activate cancer-causing substances, it primarily plays an important role in their detoxication .
It can also convert natural products found in food into anti-cancer agents .
Some anti-tumor drugs, such as phortress and aminoflavone, actually function by increasing CYP1A1 .
CYP1A1 the Bad
CYP1A1 plays a major role in activating cancer-causing chemicals, such as PAHs .
This enzyme is further involved in the activation of aflatoxin B1, a cancer-causing fungal toxin present in foodstuffs .
It also activates tobacco-related cancer-causing N-nitrosamines, such as the NNK .
Elevated CYP1A1 activity is associated with higher lung cancer risk (300 subjects).
CYP1A1 Gene Polymorphism
The C variant (more active than the T variant) can increase susceptibility to DNA damage and cancer risk. In fact, rs4646903 was associated with leukemia, cervical, hepatocellular, lung, prostate, and head and neck cancers (meta-analysis, 268 studies, 55,963 cases, and 76,631 controls) [6, 7, 8].
On the other hand, carriers of the rs4646903 C/C showed a reduced risk of rectal cancer compared with T/T carriers (2769 subjects) .
This variant may increase the risk of polycystic ovary syndrome (meta-analysis, 3489 subjects).
Increasing or Decreasing CYP1A1
These natural substances increase CYP1A1 activity:
- Indole-3-carbinol, found in cruciferous vegetables .
- Resveratrol and resveratrol-containing foods .
- Andrographolide, from the Andrographis paniculata plant .
- Astaxanthin, a pigment found in most red-colored aquatic organisms like shrimps and some algae .
- Fish oil and garlic oil .
- Green and black tea .
These natural substances decrease CYP1A1 activity:
- Berries and their component ellagic acid can reduce CYP1A1 overactivity .
- Green tea extracts .
- Sulforaphane found in broccoli .
- St. John’s Wort .
- Lycopene, a red pigment found in tomatoes, carrots, and watermelon .
- Naringenin and 6′,7′-dihydroxybergamottin (from grapefruit juice) .
- Galangin, found in some plants (Alpinia officinarum, Alpinia galanga, and Helichrysum aureonitens) and propolis .
- Zyflamend, a widely used herbal formulation produced from the extracts of ten common herbs (rosemary, turmeric, ginger, holy basil, green tea, hu zhang, Chinese goldthread, barberry, oregano, and Baikal skullcap) .
These Both Increase and Decrease CYP1A:
Many foods appear to act as both inducers and inhibitors of CYP1 enzymes, based on the dose, or the differences in active compounds:
- Curcumin at 0.1% of the diet induces this enzyme, yet a diet of 1% turmeric is inhibitory .
- Black tea at 54 mL/d induced CYP1A1, yet 20 mg/kg of theaflavins was inhibitory .
- Soybean intake at 100 mg/kg increased enzyme activity, yet at 1 g/kg black soybean extract and 200 mg daidzein twice daily was inhibitory .