Genotoksin

Genotoksin, also spelled genotoxin in English, is a substance or physical agent that damages genetic material in cells, increasing the likelihood of mutations and chromosomal alterations. Genotoxic effects can disrupt the integrity of DNA, interfere with replication, or alter chromosome structure, and may contribute to carcinogenesis if mutations affect critical genes involved in cell growth and division. Genotoxicity can result from direct interaction with DNA or from indirect processes such as the production of reactive oxygen species during metabolism.

Direct-acting genotoxins form covalent bonds with DNA, cause base modifications, or create DNA strand breaks. Indirect genotoxins require metabolic activation to become DNA-reactive and can generate crosslinks or oxidative lesions. DNA repair mechanisms, including base excision repair and double-strand break repair, reclaim much damage, but extensive or persistent exposure can overwhelm repair systems.

Common chemical genotoxins include aflatoxin B1, nitrosamines, polycyclic aromatic hydrocarbons like benzo[a]pyrene, and vinyl chloride. Physical genotoxins include ionizing radiation and ultraviolet light. Endogenous sources, such as reactive oxygen species produced during inflammation or mitochondrial respiration, can also contribute to genotoxic stress.

Genotoxicity is assessed in hazard evaluation using assays such as the Ames test, comet assay, and micronucleus test. In pharmacology and environmental health, genotoxicity data inform regulatory decisions about safety, exposure limits, and risk management. Prevention focuses on reducing exposure, minimizing metabolic activation, and supporting DNA repair through general health measures.