What does NAPQI do to cells?

What does NAPQI do to cells?

When the glutathione is completely used up, the NAPQI begins to react with liver cell proteins, killing the cells. It causes necrosis in the liver cells and kidney tubules. This same principle occurs in mushroom or toadstool poisoning.

What enzyme produces NAPQI?

Acetaminophen, or N-acetyl-p-aminophenol (APAP), is metabolized to N-acetyl-p-benzoquinone imine (NAPQI) by cytochrome P450 enzymes in the liver. The biotransformation of APAP is enhanced in P450-inducible C57BL6 (B6) mice but not in non-inducible DBA2 (D2) mice.

Why does NAPQI accumulate in the liver?

Substantial amounts of NAPQI are effectively eliminated by conjugation with glutathione (GSH). However, after a large dose of APAP, the sulfonation reaction becomes saturated and the build up of NAPQI depletes GSH in the liver, causing further accumulation of NAPQI.

How does glutathione detoxify NAPQI?

Detoxification of NAPQI occurs through its binding to the sulfhydryl group of glutathione (GSH) to form APAP-GSH, which is ultimately excreted in the urine as cysteine and mercapturic acid conjugates (APAP-cys) [5,9].

What is Glucuronidation reaction?

Glucuronidation is a conjugation reaction whereby glucuronic acid, derived from cofactor UDP-glucuronic acid, is covalently linked to a substrate containing a nucleophilic functional group. The resultant metabolite, called a glucuronide, is usually excreted in bile and urine.

Is Napqi a ros?

Mitochondrial complex I is a crucial site of ROS formation in mitochondria [54], [55], [56]. Metabolism of APAP forms the reactive metabolite NAPQI, which targets proteins, especially mitochondrial proteins.

Can I take paracetamol while taking glutathione?

Glutathione is a powerful antioxidant which can neutralise the toxic paracetamol product.

How does the liver metabolise paracetamol?

It is metabolized in the liver, predominantly by glucuronidation and sulphation to non-toxic conjugates, but a small amount is also oxidised via the cytochrome P450 enzyme system to form the highly toxic metabolite, N-acetyl-p-benzo-quinone imine (NAPQI).

What does glutathione do for the body?

Glutathione acts as an important antioxidant in your body. That means it helps combat free radicals. These are molecules that can damage your body’s cells. Glutathione plays a role in many chemical reactions in your body.

Is NAPQI a ros?

What is glucuronidation and sulfation?

Sulfation and glucuronidation are the principal metabolic pathways of flavonoids, and extensive phase II metabolism is the main reason for their poor bioavailabilities. The positional preferences were essentially maintained in a Sult-Ugt co-reaction system, although sulfation was surprisingly enhanced.

What is acetylation in drug metabolism?

Acetylation is a very common metabolic reaction which occurs with amino, hydroxyl or sulfhydryl groups. The acetyl group is transferred from acetyl-coenzyme A and the reaction is catalysed by acetyltransferases. In a few cases, the conjugates are further metabolized to toxic compounds, as is seen with isoniazid.