The ipoh tree is also known as antiaris toxicaria, the sap of which is poisonous and is used by the orang asli in their poison darts (sumpit) for hunting. Wikipedia describes the ipoh poison as follows: “The antiaris toxicaria latex sap has the active components of cardenolides and alkaloids (chemicals with cardiac arresting potential). The latex, present in the bark and foliage, contains a cardiac glycoside named antiarin, which is used as an arrow poison called upas: Javanese for poison, but, commonly to the poetic (non literal) quality of many Javanese words has a duality of meanings- watchman, messenger and courier.” This JSBRAS article from 1882 describes analysis of a sample of ipoh latex, sent by Sir Hugh Low, at the Royal Botanic Gardens in Kew, which houses the world’s largest collection of plants to this day. Sir Joseph Hooker, described in the article, was the director at Kew from 1865-1885.
Source: Journal of the Straits Branch Royal Asiatic Society, December 1882. p 162.