CYP2E1 is an important detox enzyme involved in the metabolism of alcohol. It also eliminates Tylenol (paracetamol). This enzyme clears toxins, but can also activate them. Its activity is associated with alcohol-related disorders and cancer. Read on to find out more about CYP2E1 function, genetics, and factors that increase or decrease enzyme activity.
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 .
CYP2E1 The Good
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 The Bad
CYP2E1 Gene Polymorphism
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.
C increases the risk of hypertension (elevated blood pressure) in men with alcohol abuse .
This variant increases the risk of alcoholism in men (101 subjects) .
rs3813865 is associated with high altitude polycythemia (increase in red blood cells) in Tibetans (194 subjects) .
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