Aglycone of saponin dioscin. From Dioscorea tokoro Makino, Dioscoreaceae: Tsukamoto, J. Pharm. Soc. Jpn. 56, 135 (1936); from rhizomes of Trillium erectum L., Liliaceae and D. villosa L., Dioscoreaceae: Marker et al., J. Am. Chem. Soc. 62, 2542 (1940). Plant sources for diosgenin: Marker et al., ibid. 65, 1199 (1943); Wall et al., J. Am. Pharm. Assoc. Sci. Ed. 46, 653 (1957). Identity with nitogenin: Marker et al., J. Am. Chem. Soc. 65, 1248 (1943). Structure: Marker et al., ibid. 62, 2525 (1940). Configuration at C25: James, J. Chem. Soc. 1955, 637. Synthesis: Mazur et al., J. Am. Chem. Soc. 82, 5889 (1960); Kessar et al., Tetrahedron Lett. 1966, 4319. Obtained commercially from Dioscorea composita Hemsl. and D. terpinapensis Uline (see under Barbasco). Isoln from barbasco varieties: Julian, US 3019220 (1962 to Julian Labs.).