Answer: saponins

AnswerCrossword Clue
saponinsAny of the class of steroid and terpenoid glycosides typified by this, examples of which are used in detergents and foam fire extinguishers
saponinsA toxic compound that is present in soapwort and makes foam when shaken with water
saponinsSAPONIN, a soapy substance obtained from plants, also SAPONINE