ABSTRACT
Several members of the potato family, Solanaceae, contain chemical compounds known as antimuscarinic tropane alkaloids, which include atropine, hyoscine (the l-isomer of which is known as scopolamine) and hyoscyamine. The principal plants that produce antimuscarinic tropane alkaloids are: Atropa belladonna (deadly nightshade), Datura stramonium (thorn apple), D. ferox, D. innoxia, Scopolia carniolica, Brugmansia suaveolens (angels’ trumpets), and Mandragora officinarum (mandrake). Before their alkaloids were in use medicinally, the unrefined extracts were given their plant names: belladonna, stramonium and henbane. Tropane alkaloids with different mechanisms of action are produced by other plants, for example cocaine from Erythroxylum coca (q.v.). In a series of key animal experiments reported in 1840, the eminent chest physician Charles Williams showed that extracts of both belladonna and stramonium almost abolished the airway contraction induced by stimulation of the vagus nerve. Physostigmine is a reversible inhibitor of acetylcholinesterase, which breaks down acetylcholine, the transmitter which stimulates the muscarinic receptor.
