THE ESR PROPERTIES, DNA NICKING, AND DNA ASSOCIATION OF AGED SOLUTIONS OF CATECHOL VERSUS AQUEOUS EXTRACTS OF TAR FROM CIGARETTE-SMOKE

Previous studies in our laboratories have shown that extracts from mai nstream or sidestream tobacco smoke nick DNA. These solutions contain the tar semiquinone free radical, and the tar radical becomes associat ed with cellular DNA. Aged solutions of catechol contain a semiquinone species that has ESR properties similar to those of the radical in ci garette tar extracts, and we have used these catechol solutions as a m odel for the tar radical. Both the radical in aged catechol solutions and the cigarette tar radical become associated with the DNA in mammal ian cells and also nick DNA. The nicking of DNA caused by both tar and aged catechol solutions follows saturation kinetics. Aged catechol so lutions thus allow the study of a model for the radical present in cig arette tar, without interference from the other toxic constituents in tar extracts. (C) 1995 Academic Press, Inc.