Nicotine is a natural alkaloid obtained from the dried leaves and stems of the nightshade family of pants, such as Nicotiana tabacum and Nicotiana rustica, where it occurs in concentrations of 0.5-8%. Cigarette tobacco varies in its nicotine content, but common blends contain 15-25 mg per cigarette, with a current trend towards lower levels. Nicotine is highly addictive substance, it exhibits a stimulant effect when adsorbed at 2 mg. Administration of higher doses could be harmful. Action of nicotine is mediated by nicotinic cholinergic receptors. Nicotine binds to the interface between two subunits of the receptors, opens the channel and allows the entry of sodium or calcium. The principal mediator of nicotine dependence is α4β2 nicotine receptor.

Dianicline binds with high affinity to the rat and human alpha4beta2 nicotinic acetylcholine receptor (nAChR) subtypes and displays selectivity for the alpha4beta2 nAChR. Electrophysiological experiments indicate that dianicline is a partial agonist at the human alpha4beta2 nAChR subtype. Pretreatment with dianicline reduces the dopamine-releasing and discriminative effects of nicotine. Dianicline shows activity in animal models of nicotine dependence at doses devoid of unwanted side effects typically observed with nicotine. Dianicline did not increase cigarette smoking abstinence rates beyond the initial phase of treatment. However, self-reported craving and nicotine withdrawal symptoms were reduced. The most common adverse event for subjects receiving dianicline was nausea. Other gastrointestinal disorders also tended to be more frequent in the dianicline group, including diarrhea.

Nicotine-1'-N-oxide (NNO) is an oxidation product of nicotine. Flavin-containing monooxygenase is responsible for the oxygen transfer. Nicotine N'- oxide is a primary metabolite of nicotine, although only about 4-7% of nicotine absorbed by smokers is metabolized via this route. It appears that NNO is not further metabolized to any significant extent, except by reduction back to nicotine, which may lead to recycling of nicotine in the body.

(1'S,2'S)-nicotine-1'-N-oxide is a stereoisomer of nicotine-1'-N-oxide, an oxidation product of S-(-)-nicotine. N-1'-oxidation of nicotine is mediated via flavin-containing monooxygenase. A marked stereoselectivity has been observed in the formation of N-1'-oxide metabolites from nicotine. Mammal hepatic preparations generally produce more the N-1'R,2'S-cis diastereoisomer than N-1'S,2'S-trans diastereoisomer after incubation with S-(-)-nicotine. (1'S,2'S)-nicotine-1'-N-oxide was reported to bind alpha3beta4 neuronal nicotinic acetylcholine receptor. cis- and trans-nicotine-N'-oxides modulate the development of tumors in rats initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide.

1-methyl-4-(3-pyridinyl) pyrrole (β-nicotyrine) is a tobacco alkaloid. It is a potent inhibitor of cytochrome P450 CYP2A13 and a mechanism-based inactivator of cytochrome P450 CYP2A6.