Nicotine is a naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and Duboisia hopwood and is widely used recreationally as a stimulant and anxiolytic. Nicotine constitutes approximately 0.6–3.0% of the dry weight of tobacco. Nicotine is also present at ppb-concentrations in edible plants in the family Solanaceae, including potatoes, tomatoes, and eggplants, though sources disagree on whether this has any biological significance to human consumers. Nicotine is highly addictive unless used in slow-release forms. Animal research suggests that monoamine oxidase inhibitors present in tobacco smoke may enhance nicotine's addictive properties. Tobacco with reduced nicotine (denicotinized tobacco) acutely reduces nicotine withdrawal, raises striatal dopamine and is also investigated as add on therapy to standard therapy to quit smoking. An average cigarette yields about 2 mg of absorbed nicotine. The estimated lower dose limit for fa