Datura species

Abstract

DISTRIBUTION: Possibly originating in tropical America, it is now widely distributed in South Africa, especially in disturbed soil, like seasonal river courses, cultivated lands and along roadsides.BOTANICAL DESCRIPTION: General: A large-leafed, robust annual weed. The most characteristic feature is its hardened spiny fruit capsules, which contain a very large number of small black compressed kidney-shaped seeds.TOXIC PRINCIPLE: The seeds are the most poisonous part of D. stramonium and contain the alkaloids atropine and hyoscine.MECHANISM OF ACTION: • These alkaloids are parasympatholytic compounds.SYSTEMS AFFECTED: Central nervous system.CLINICAL SIGNS: • Humans are exceptionally susceptible to poisoning. • Livestock is not often affected; horses are more commonly the victims of Datura poisoning. • Rabbits are resistant, due to atropine esterases. • Clinical signs include - mydriasis and cycloplegia, - tachycardia, - dryness of the mouth, - colic and tremors.