Summary
Xenobiotics are chemical compounds foreign to the body, such
as drugs, food additives, and environmental pollutants
Xenobiotics are metabolized in two phases. The major reaction
of phase 1 is hydroxylation catalyzed by a variety of
monooxygenases, also known as the cytochrome P450s. In
phase 2, the hydroxylated species are conjugated with a variety
of hydrophilic compounds such as glucuronic acid, sulfate, or
glutathione. The combined operation of these two phases
renders lipophilic compounds into water-soluble compounds
that can be eliminated from the body.
Xenobiotics can produce a variety of biologic effects, including
pharmacologic responses, toxicity, immunologic reactions, and
cancer.