Saponins are plant chemicals are used for their detergent-like or cleaning properties. Some of the better known are Saponaria officinalis from Europe and Quillaja saponaria from South America. Saponin molecules have two parts; a sapogenin attached to a carbohydrate molecule. These two part types of molecules are collectively called glycosides. The sapogenin portion alone, without the carbohydrate or sugar is an aglycone rather than a glycoside. Sapogenins are generally of two types; a steroid like form and a triterpenoid form.
Besides being able to produce a froth in water, saponins have anti-inflammatory and antioxidant properties. The sapogenin is hydrophobic (water hating) and the glycoside or carbohydrate is hydrophilic (water loving). This makes saponins in general a natural surfactant as well as a mild emulsifier.
Other plants that produce saponins include yucca, soapwort (Saponaria), licorice, ginseng, yarrow, viola, and soap nuts. Some saponins are also phytoestrogens and react with the estrogen receptor to provide skin benefits.
While I’ve never actually been able to work up a froth from agitating licorice, yarrow or viola, I do think they make nice additions to a mix of bath herbs for their cleansing properties.
Do you ever use saponin containing herbs?