2-Hydroxynicotine is a metabolite of the degradation of Nicotine (Nicotine is an alkaloid found in the nightshade family of plants (Solanaceae), predominantly in tobacco, and in lower quantities in tomato, potato, eggplant (aubergine), and green pepper) via a 2'-hydroxylation reaction producing 2'-hydroxynicotine as an intermediate in the cytochrome P450 2A6 [EC 1. 14. 14. 1] catalyzed conversion of nicotine to 4-(methylamino)-1-(3-pyridyl)-1-butanone. 2'-Hydroxynicotine spontaneously yields nicotine-1'(2')-iminium ion, which is in equilibrium with 4-(methylamino)-1-(3-pyridyl)-1-butanone. About 10% of nicotine and metabolites is excreted as 4-oxo-4-(3-pyridyl)butanoate (keto acid) and 4-hydroxy-4-(3-pyridyl)butanoate (hydroxy acid) in the urine of smokers.