Polycyclic aromatic hydrocarbon (PAH)

Polycyclic aromatic hydrocarbons (PAHs) are a large class of organic environmental pollutants consisting of two or more fused aromatic rings containing only carbon and hydrogen[1][5][9]. They are uncharged, nonpolar, hydrophobic molecules, usually found as solids that are relatively insoluble in water and have low volatility at room temperature[9]. PAHs are typically formed during incomplete combustion of organic materials, and they are widely distributed in the environment, present in fossil fuels and as contaminants in food, air, and water[4][9]. While PAHs are of intense biological and medical interest due to their toxicity, mutagenicity, and especially their role in carcinogenesis, they are not themselves therapeutic targets, enzymes, receptors, or proteins[1][5]. Rather, they act as ligands for certain biological receptors, most notably the aryl hydrocarbon receptor (AhR); interactions with AhR upregulate metabolic enzymes (e.g., cytochrome P450s) that metabolize PAHs to reactive, mutagenic intermediates[2][5][8]. Their toxic, carcinogenic, and immunomodulatory bioeffects are mediated both through receptor binding and direct interference with cellular structures and communication[5][6]. PAHs are notable for bioaccumulation—particularly in fat-rich tissues, breast milk, and the liver—and for their environmental persistence due to chemical stability and resistance to degradation[4][7][9]. Chronic human exposure to PAHs, especially to high-molecular-weight compounds like benzo[a]pyrene, is associated with increased risk of cancer, lung inflammation, and systemic toxicity[4][6]. Biomarkers such as 1-hydroxypyrene and 8-OHdG are used to monitor exposure and effects[8][6]. Due to their structure and properties, “polycyclic aromatic hydrocarbon” is not a therapeutic target, but rather a class of chemical toxicants. The query is incorrect in identifying PAH as a druggable target or biomolecule ("is_incorrect: true").

Other names

Polynuclear aromatic hydrocarbonPolyaromatic hydrocarbonPNA