Wikipedia
Dioscorine is an alkaloid toxin isolated from the tubers of tropical yam in different continents. It has been used as a monkey poison in some African countries, and as an arrow poison to aid in hunting in several parts of Asia. It was first isolated from Dioscorea hirsute (synonymous with Dioscorea hirsuta) by Boorsma in 1894, and obtained in a crystalline form by Schutte in 1897. Dioscorine is a neurotoxin that acts by blocking the nicotinic acetylcholine receptor. Dioscorine is generally isolated in tandem with other alkaloids such as dioscin but is usually the most potent toxin. It is a convulsant; it produces symptoms and has a mechanism of action similar to picrotoxin. (Dioscorine is not to be confused with dioscorin, the yam storage protein.)