Djerassi C., Farkas E., Lemin A. J., Collins J. C., Walls F., Terpenoids. VI. Dumortierigenin, a New Triterpene Lactone from the Cactus Lemaireocereus dumortieri, Journal of the American Chemical Society, 1954, 76(11):2969-2973, doi: 10.1021/ja01640a033
The available first page describes isolation of dumortierigenin after hydrolysis of cactus glycosides and examination of its functional groups. The historical account uses only information visible in that excerpt.