The term tropane alkaloids refers to a group of more than 200 compounds best known for their occurrence in the family Solanaceae comprising over 100 genera and 3,000 plant species. The most important natural tropane alkaloids are (-)hyoscyamine, its stable racemate, atropine and (-)scopolamine. Important sources of these alkaloids are Belladonna sps, Duboisia sps, Datura sps, Hysocyamus sps and Scopolia sps.

Commercial Importance

Tropane derivatives are among the economically most important pharmaceuticals. Various pharmaceutical industries are manufacturing over 20 active pharmaceutical ingredients containing tropane moiety in their structures and these are applied as mydriatics, anti-emetics, antispasmodics, anaesthetics and bronchodilators. The natural tropane akaloids are anticholinergic and are themselves of medicinal interest. Atropine has a stimulant action on the CNS and depresses the nerve endings to the secretory glands and plain muscle. Sedative properties of hyoscine enable it to be used in the control of motion sickness and it lacks the central stimulant action of atropine. Hyoscine hydrobromide is employed in pre-operative medication, usually with papaveretum, some 30–60 minutes before the induction of anaesthesia. Atropine and hyoscine are used to a large extent in ophthalmic practice to dilate the pupil of the eye. Homatropine, ipatropium bromide, oxitropium bromide and benztropine are some important drugs related to tropane alakaloids.

The source plants, long known for their poisonous nature, have been used for their medicinal property in traditional herbal medical practice.

Constituents

All the above named solanaceous plants contain the mentioned natural tropane alkaloids together with other minor alkaloids. Table 3.4 lists the important sources of tropane alkaloids.