The initial biotransformation of most organic chemicals (phase I metabolism) is catalyzed by the cytochrome P450 enzymes of the endoplasmic reticulum of liver cells. This superfamily of enzymes oxidizes and reduces carbon and a number of heteroatoms.
Does biotransformation happen in the liver?
The majority of biotransformation takes place within the liver in cells called hepatocytes. However, several of the enzymes for phase I, phase II, and phase III reactions can also occur in extrahepatic tissues, such as adipose, intestine, kidney, lung, and skin.
What is non enzymatic biotransformation?
Non Enzymatic Elimination: Spontaneous, non-catalyzed and non-enzymatic type of biotransformation for highly active, unstable compounds taking place at physiological pH. Very few drugs undergo non-enzymatic elimination. Some of these include: Mustin HCl converted into Ethyleneimonium.
What is enzymatic biotransformation?
Enzymatic biotransformation is a very useful approach to expand the chemical diversity of natural products. Recent enzymatic biotransformation studies on terpenoids have resulted in the isolation of novel compounds. 3,11-Dioxo-olean-12-en-30-oic acid, was found to be more active than the parent compound.
What occurs in biotransformation?
Biotransformation is the process by which substances that enter the body are changed from hydrophobic to hydrophilic molecules to facilitate elimination from the body. This process usually generates products with few or no toxicological effects.
What are the factors affecting biotransformation?
Biotransformation of drugs to polar metabolites is a key step in the termination of action and the elimination of drugs used in therapeutics. A large number of factors, including infection, alter the basal rates of drug metabolism and cause a number of untoward effects and drug interactions.
What happens during biotransformation?
What are the two types of biotransformation reactions?
Biotransformation is of two types: Enzymatic and Non-enzymatic. Enzymatic are further divided into Microsomal and Non-microsomal. Enzymatic Elimination is the biotransformation occurring due to various enzymes present in the body.
What are the four types of biotransformation process?
Drugs can undergo one of four potential biotransformations: Active Drug to Inactive Metabolite, Active Drug to Active Metabolite, Inactive Drug to Active Metabolite, Active Drug to Toxic Metabolite (biotoxification).
Why is the liver the most important organ in biotransformation of xenobiotics?
The liver also has the highest supply of biotransformation enzymes of all organs in the body. Therefore, it has a key role in xenobiotic detoxification and protection against chemical toxicity. Biotransformation can be categorised into hydrolysis, reduction, oxidation and conjugation reactions.
Why do some drugs inhibit the biotransformation process?
FACTORS AFFECTING BIOTRANSFORMATION Enzyme inhibition occurs when 2 drugs sharing metabolism via the same isozyme compete for the same enzyme receptor site. The more potent inhibitor will predominate, resulting in decreased metabolism of the competing drug.
Why stereochemistry is important in drug metabolism?
Stereochemistry influences not only the disposition and activity of the parent drug but also the nature and potential pharmacological activity of the metabolites formed. Many recent developments are furthering our understanding of drug metabolism and the implications of stereochemistry.
What is the role of liver in biotransformation?
The liver is responsible for the biotransformation and clearance of a variety of endogenous and exogenous toxic compounds. Exogenous organic substances entering the body that have no nutritive value for energy production, structural function, or enzyme cofactor function are called xenobiotics.
What causes toxic xenobiotics to transform into biotransformation?
The liver is the one that causes toxic xenobiotics to transform into biotransformation and going through phase 1 and 2 to excrete the toxins out of the body for a healthy function. Phase 1 reactions in the body are the first line of defense of the body detoxifying itself.
What are the two types of biotransformation?
It is highly important for a person to detox their body and with biotransformation, it can be classified into two categories, under normal sequences, which tends to react with a xenobiotic. They are called Phase 1 and Phase 2 reactions that help the body with detoxification. Phase 1 reaction is consisting of oxidation-reduction and hydrolysis.
Do extrahepatic tissues play a role in the biotransformation of drugs?
Relative to liver, extrahepatic tissues do not normally play a major quantitative role in the biotransformation of foreign compounds, including drugs.
