The half life of nicotine in tobacco plants is about 22 hours. Approximately 40-60 mg of nicotine is a lethal dose for an adult human. Ricinine, also derived from nicotinic acid, is found in castor bean plants, Ricinus communis , Euphorbiaceae. Arecoline, from Areca catechu , Arecaceae, the betel palm, is the stimulating alkaloid in betel or pan. This alkaloid has muscarinic action, that is, it mimics acetylcholine and binds to acetylcholine receptors.
Low doses produce vasodilation and a fall in both systolic and diastolic blood pressure.
This masticatory substance is used by at least one billion people daily, mainly in Southeast Asia. Trigonelline promotes arrest in G 2 -stage of the cell cycle.