CYP2E1 is an important detox enzyme involved in the metabolism of alcohol and Tylenol (paracetamol). This enzyme clears toxins but can also activate them. Its activity is associated with alcohol-related disorders and cancer. Read on to learn more about the CYP2E1 function, genetics, and factors that increase or decrease enzyme activity.
What is CYP2E1?
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 .
Roles in Health
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 removal of neurotoxins related to Parkinson’s, such as heavy metals and pesticides .
Roles in Disease
CYP2E1 deficient mice are resistant to alcohol-induced gut leakiness and liver inflammation .
It’s important to note that just because certain genotypes are associated with a condition or irregular lab marker, it doesn’t necessarily mean that everyone with that genotype will actually develop the condition. Many different factors, including other genetic and environmental factors, can influence the risk of conditions described below.
There are several CYP2E1 variants that influence this enzyme’s activity.
Basically, even you have more than two copies, they are not active.
Factors That Increase/Decrease CYP2E1
The clinical relevance of changing the activity of CYP3A5 is not yet fully understood. In theory, it may impact the safety and efficacy of drugs metabolized by this enzyme.
These may 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