Updated June 09, 2015.

Definition:

Saponins are plant-based anti-inflammatory compounds that may lower your blood cholesterol and prevent heart disease as well as some cancers. Saponins can be found in legumes, and form a soapy-looking foam when you shake the pot liquid of cooked dry beans, or add water to soaked beans or lentils. These compounds have a bitter taste, and are considered toxic in large amounts, which is why the water from soaked legumes should be discarded, and fresh water added, before cooking.

Pronunciation: SAP-uh-nin or SAP-o-nin

Common Misspellings: sapanin, saponine

Examples:

Saponins occur in legumes, soapwort, herbs, red wine, and some seafoods. They are used commercially in detergents, fire extinguishers, and emulsifiers. Saponins are being studied for their medicinal uses, including antispasmodic activity, and toxicity to cancer cells.

_{Image provided by RCSB Protein Data Bank: Kervinen, J., Tobin, G.J., Costa, J., Waugh, D.S., Wlodawer, A., Zdanov, A. (1999) Crystal structure of plant aspartic proteinase prophytepsin: inactivation and vacuolar targeting. EMBO J. 18: 3947-3955}