Xenobiotics are substances that are foreign to the body or not naturally produced by the organism. The term comes from the Greek words xeno (foreign) and bios (life).
Examples of xenobiotics:
Drugs (e.g., antibiotics, painkillers)
Environmental pollutants (e.g., pesticides, heavy metals)
Food additives or preservatives
Cosmetics and personal care chemicals, Industrial chemicals.
In pharmacology and toxicology:
Xenobiotics are important because the body must metabolize and eliminate them, usually through:
Phase I reactions (oxidation, reduction, hydrolysis – mainly by cytochrome P450 enzymes)
Phase II reactions (conjugation – to make them more water-soluble for excretion)
Significance:
Understanding xenobiotics is crucial for drug design, toxicology, and environmental science, as these substances can sometimes cause toxicity, allergies, or disrupt normal biological functions.