Another way to make soap without lye is to use plants that are high in saponin, a soapy substance.
Digitonin, on the other hand, is a cardiac depressant, and has been found to be identical with saponin, the chief constituent of senega root.
This body, which is named parillin, is allied to the saponin of quillaia bark, from which it differs in not exciting sneezing.
From the seeds have been obtained starch (about 14%), gum, mucilage, a non-drying oil, phosphoric acid, salts of calcium, saponin, by boiling which with dilute hydrochloric or sulphuric acid aesculic acid is obtained, quercitrin, present also in the fully developed leaves, aescigenin, C12H2n02, and aesculetin, C 9 H 6 O 4, which is procurable also, but in small quantity only, from the bark.
- Saponin and many allied bodies form an abundant soapy-looking froth when shaken up with water, and they are contained in a very large number of plants, the chief of which are the Quillaia saponaria, Polygala senega, sarsaparilla, and others, known collectively as soapworts.