The saponin of quillay bark. Isolation: Kobert, Arch. Exp. Pathol. Pharmakol. 23, 233 (1887); Pachorukow, Arbeiten des Pharmakologischen Instituts zu Dorpat I, 5 (1888); Cofman-Nicoresti, Pharm. J. 111, 103 (1923), found the total saponin content of quillay bark to be ≈9 or 10%. The saponin is built from quillaic acid, a sugar and possibly other substances.