Amazonian Tribes: Plants for Small Diseases to Birth Control (Manu-Peru, and the Machiguenga)

On the virgin jungle of the Amazon in South America several tribes still remain, struggling against the expansion of the civilization. A (virtual) visit to those places would always permit the explorer to discover new things, keeping several yet to be discovered if such will ever be possible some day. Among all the samples, the Machiguenga of the Manu National Park in the Peruvian Amazon provide only an example of the enormous bank of knowledge yet to be discovered. Among all the knowledge provided, we all know that the use of plants for the treatment of diseases is a known fact applied until our days in the cities that lay aroud the Amazon basin and far beyond, but something I did not know is that those plants would even provide the means for contraception for locals. On the documentary of Alejandro Guerrero on the Machuiguenga tribe, what grabbed my attention was the point where he mentioned the properties of an interesting species that is used as a contraceptive mean; the name is "unchashi" which I could not find in Google, perhaps because it remains as an unclassified species....only an example of the richness hidden in the jungle.
References.-John W. Terborgh: He is one of the scientists who work at the Park. "The people of Manu". A blog with some information on the site.La Reserva de Biósfera del Manu. The documentary from which I take the brief info described,