sapotoxin

from The Century Dictionary.

• noun A glucoside, C₁₇H₂₆O₁₀, found in Levantine soap root from Gypsophila Arrostii or G. paniculata. It is a white powder which gives a foam in aqueous solutions. It has a burning taste, and attacks the mucous membranes strongly. Kobert has proposed to use the name sapotoxin also for those varieties of the saponin glucosides which are poisonous.