What is CYP2E1?
CYP2E1 is one of the cytochrome P450 monooxygenases (CYPs). These are enzymes that eliminate most of the drugs and toxins from the human body .
This enzyme metabolizes:
- Small organic molecules such as alcohol, acetone, and pyrazole [2, 3].
- Fatty acids, ketone bodies, and glycerol [2, 4].
- Clinically-used drugs such as salicylic acid, halothane, isoniazid, and isoflurane , Tylenol (paracetamol/acetaminophen), and phenobarbital .
- Toxic chemicals including carbon tetrachloride and chloroform .
- Cancer-causing agents present in the diet and tobacco smoke, such as nitrosamines, aniline, and benzopyrene [6, 5].
- Environmental toxins such as benzene, and acrylamide .
This enzyme is found in various tissues including the brain, lungs, and kidneys. It is most concentrated in the liver .
The enzyme is responsible for approximately 20% of alcohol metabolism in the brain .
CYP2E1 acts as a double-edged sword. It is responsible for the detoxification of the environmental toxins . However, it can also activate many of them.
Although some studies suggest CYP2E1 activity is implicated in Parkinson’s disease, other studies show that CYP2E1 brain activity is beneficial. This enzyme can have beneficial effects due to its efficient removal of neurotoxins related to Parkinson’s, such as metals and pesticides .
CYP2E1 deficient mice are resistant to alcohol-induced gut leakiness and liver inflammation .
There are several CYP2E1 variants that influence this enzyme’s activity.
CYP2E1 gene duplications and deletions also exist. However, these don’t have a large impact on CYP2E1 activity, because of a gene dosage compensation mechanism (unlike what happens with CYP2A6 and CYP2D6) . Basically, even you have more than two copies, they are not active.
Smokers and excessive drinkers with C/C have a higher risk of lung cancer than people with at least one T (841 subjects) .
C in this position increases breast cancer risk 1.8-fold in Malaysian women (431 subjects) .
C increases the risk of hypertension (elevated blood pressure) in men with alcohol abuse .
Increasing or Decreasing CYP2E1
These increase CYP2E1:
- Alcohol 
- Nicotine 
- Ketone bodies 
- Hypoxia 
- Fasting 
- Omega-3 polyunsaturated fatty acids 
- Obesity and diabetes 
- Pyrazole, acetone, and isoniazid 
- Non-alcoholic fatty liver disease (NAFLD) 
These decrease CYP2E1:
- Starfruit juice 
- Watercress 
- Propolis 
- Garlic [29, 30, 31] and its component diallyl disulfide 
- Green and black tea 
- Resveratrol (found in grapes, blueberries, raspberries, mulberries ) [34, 35]
- Quercetin [36, 37]
- Piperine (found in pepper) 
- Curcumin 
- Phenethylisothiocyanate, found in watercress and cruciferous veggies 
- Ellagic acid 
- Licochalcone A, found in traditional Chinese herbal licorice 
- Dandelion leaf 
- Danshen (Salvia miltiorrhiza) extract [44, 45]
- Goldenseal (Hydrastis canadensis) 
- Alhagi-honey extract 
- Cornus officinalis extract 
- Apocynum venetum 
- Clomethiazole