Toxicity Of Cigarette Smoking Linked To DNA Damage From Tar Extracts

Cigarette tar is deposited in the lungs of smokers, and these lung tissues are continuously bathed in an aqueous solution that can dissolve and transport the water-soluble chemicals in the tar. According to William A. Pryor, Ph.D., Director of the Biodynamics Institute at Louisiana State University, this aqueous cigarette tar (ACT) extract is a complex mixture of hundreds of compounds that can cause DNA damage. Now Pryor's research has shown that some of the most active compounds in ACT are compounds called hydroquinones, and their derivatives, quinones and semiquinones. (Semiquinones are free radicals -- reactive chemical species that have an odd number of electrons.) Using mammalian cells, Pryor has shown that these semiquinone free radicals are critically involved in causing DNA damage of a type that is not easily repaired and therefore might lead to mutations and cancer. "It is very likely that these highly reactive free radicals are involved in the toxicity associated with cigarette smoking," Pryor says.

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