Occurs as glycoside in many saponins, see α-Hederin. Isoln and structure: van der Haar, Arch. Pharm. 250, 424 (1912); Ruzicka et al., Helv. Chim. Acta 28, 380 (1945); Haynes et al., J. Chem. Soc. 1963, 744. Identity with melanthigenin: Mustafa, Soliman, ibid. 1943, 70. Identity with caulosapogenin: McShefferty, Stenlake, ibid. 1956, 2314. Molecular and crystal structure: R. Roques et al., Acta Crystallogr. B34, 1634 (1978). See also α- and β-Amyrin and Oleanolic Acid.