Strophanthus are the dried ripe seeds of Strophanthus kombe or Strophanthus hispidus, belonging to the family Apocyanaceae. They are also known as semino strophanthi and arrow poison. Strophanthus is a climber and the extract of the seeds of this plant is used by the tribals as arrow poison.
It is indigenous to the regions near the Shire river, Nyanza and Tanganyika lakes of Eastern tropical Africa. The seeds are bitter in taste and have unpleasant odour. They are silky in touch due to the presence of trichomes.
The drug contains a mixture of glycosides called K-strophanthin, which constitutes K-strophanthoside (strophoside), K-strophanthoside B cymarin and cymarol. Except cymarol, all other glycosides yield strophanthidin on hydrolysis. K-strophanthoside is the primary glycoside and on hydrolysis it gives aglycone strophanthidin and 3 sugars cymarose, a and B glucose.
The drug also contains other constituents like resin, mucilage, trigonelline, choline and fixed oil.
It is used as a cardiotonic. It is mainly a source of K-strophanthin. The drug is given parenterally due to its poor absorption by oral route.