Xenobiotika

Xenobiotika is a term used in biology and environmental science to describe xenobiotics, compounds that are foreign to an organism's normal metabolism. The name combines Greek xenos meaning foreign with bios meaning life and -tikos meaning pertaining to. Xenobiotika include pharmaceuticals, pesticides, industrial chemicals, food additives, and environmental pollutants. They can originate from many sources and may enter organisms via ingestion, inhalation, or dermal contact.

Fate and metabolism: In many animals, xenobiotika are processed primarily in the liver by phase I and phase II metabolism. Phase I reactions, often catalyzed by cytochrome P450 enzymes, introduce or unmask functional groups; Phase II reactions attach polar groups such as glucuronide, sulfate, or glutathione conjugates. Metabolites are generally more water-soluble and excreted via urine or bile. Some xenobiotics are bioactivated into more reactive species; others are detoxified. Transport proteins can influence distribution and excretion.

Health and environmental effects: Effects range from therapeutic benefits to toxicity. Dose, exposure duration, and individual factors determine outcome. In ecosystems, xenobiotics can accumulate and impact wildlife, altering reproduction or behavior. Persistent organic pollutants can persist and biomagnify.

Regulation and research: Risk assessment considers hazard identification, dose–response, exposure, and risk characterization. Regulatory agencies monitor and regulate certain xenobiotics, and environmental monitoring tracks their levels. Ongoing research covers pharmacokinetics, toxicology, metabolism, and remediation strategies such as biodegradation.