Saponin
senegin; polygalin; a substance first observed in the common soapwort, but now found to be widely diffused through the vegetable kingdom. Quillaja bark, horse chestnuts, and senega root yield it in considerable quantities. The powdered substance is boiled in strong alcohol and filtered hot; the saponin separates in flocks on cooling SAPPHO is a white friable powder, having a burning and persistently disagreeable taste, is more soluble in dilute than strong alcohol, and forms with water a frothy solution. It is often used to give an artificial froth to beer and effervescing beverages.