Studies on the Pyrrolinone Metabolites Derived from the Tobacco Alkaloid 1-Methy1-2-(3-pyridinyl)pyrrole (beta-Nicotyrine)

Previous studies have established that the tobacco alkaloid 1-methy1-2-(3-pyridyl)pyrrole (beta-nicotyrine) is biotransformed by rabbit lung and liver microsomal preparations to an equilibrium mixture of the corresponding 3- and 4-pyrrolin-2-ones. Autoxidation of these pyrrolin-2-ones generates the chemically stable 5-hydroxy-5-(3-pyridinyl)-3-pyrrolin-2-one. This paper summarizes efforts to document more completely the pathway leading to this hydroxypyrrolinone. Chemical and spectroscopic evidence implicates the 2-hydroxy-1-methy1-5-(3pyridinyDpyrrole (2-hydroxy-beta-nicotyrine) as the key intermediate in this reaction pathway. Of potential toxicological interest is the detection of radical species derived from the autoxidation of this compound.