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.
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.
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.
Central nervous system.
• 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,
- dryness of the mouth,
- colic and tremors.
Colour photos. Final web-ready size: JPEG, 72 ppi. Photo 1: 12.6 kb; Photo 2: 72.7 kb; Photo 3: 16.3 kb; Photo 4: 10.9 kb; Photo 5: 9.1 kb. Original TIFF file housed at the Dept. of Paraclinical Sciences, Section Pharmacology and Toxicology, University of Pretoria.