Saponins

Saponins are found in many plants and gained their name because like soap, they form a lather when combined with water

Chemically they are based on a Steroid or Triterpene fat-soluble base joined to a water-soluble sugar molecule, creating a detergent that results in the emulsification of fat-soluble molecules in the digestive tract of the body. Note: Both steroid & Triterpene types usually found existing together.

In plants saponins are found especially in plant skins where they form a waxy protective coating. It has also been found that saponins are a major part of the plants’ active immune system and function as a ”natural antibiotic” for plants.

The chemical structure of steroidal saponins is similar to that of many of the body’s hormones, for example estrogen and cortisol, and many plants containing them have a marked hormonal activity. Their aglycone portion is referred to as the sapogenin. Note: the steroidal saponins in Dioscorea villosa (Wild Yam) were the basis from which the contraceptive pill was first developed and currently many bioidentical hormones.

Triterpenoid saponins have less hormonal activity. They are often expectorant and will aid absorption of nutrients.

Among the chemical properties of saponins, their polarity, hydrophobicity and nature of the reactive groups seem important determinants of their biological properties, and has also made them difficult compounds to both isolate and research.

Major Actions of Saponins in the Body: 

Properties of saponin containing herbs are many & varied and may include alterative, diuretic, expectorant, anti-catarrhal, anti-inflammatory, antispasmodic, aphrodisiac, antioxidant, emmenagogue, cardiac stimulant, hormone modulating, hepatoprotective, and adrenal adaptogenic effects. Possibly their most important property is to accelerate the body’s ability to absorb other active compounds. Some of their more specific noted effects include:

• Hepatoprotective providing Kuppfer cell support in the liver promoting detoxification
• Adaptogen (or Adrenal tonic effect) & Hormone modulating by mimicing our endogenous hormones and specifcally sparing cortisol
• Stimulating expectorant effect via activation of mucociliary escalator and mucous membrane irritation
• Diuretic effect via local irritation of kidney epithelia
• Gentle Detoxifiers eliminating toxic buildup in various ways throughout the body
• Cholesterol lowering by binding with cholesterol so it cannot be re-absorbed into the system. Bile acids form mixed micelles with cholesterol, facilitating its absorption. Saponins cause a depletion of body cholesterol by preventing its reabsorption, thus increasing its excretion, in much the same way as other cholesterol-lowering drugs (sequestrants). Note: The binding of bile acids by saponins has other important implications, as primary bile acids are metabolized by bacteria in the colon, producing secondary bile acids which can be promoters of colon cancer (see anti-cancer effects).

• Anti-cancer – The proposed mechanism of anti-carcinogenic properties of saponins include antioxidant effect, direct and select cytotoxicity of cancer cells, immune-modulation, acid and neutral sterol metabolism and regulation of cell proliferation. Cancer cells also have more cholesterol-type compounds in their membranes than normal cells, thus as saponins can bind cholesterol and they may interfere with cell growth and division of cancer cells.

Toxicity Effects

Saponins can have an irritating effect on mucous membranes of the respiratory and digestive tract, potentially causing sneezing, bloating, gastroenteritis, nausea, diarrhea, and vomiting.

Saponins have also been noted for their hemolytic properties as they can effectively “dissolve” the cell walls of red blood cells and disrupt them when taken intravenous or intramuscularly. When take orally however they are comparatively harmless or they are not absorbed at all.

Note: Humans generally do not suffer severe poisoning from saponins. Our cholesterin inactivates them so that only our mucus membranes are affected. Some however are poisonous if swallowed and can cause urticaria (skin rash) in many people. Any markedly toxic saponin is known as a sapotoxin.

Herbal examples:

• Dioscorea villosa (Wild Yam)
• Panax ginseng (Chinese or Korean Ginseng)
• Glycyrrhiza glabra (Licorice)
• Aesculus hippocastanum (Horsechestnut)
• Medicago sativa (Alfalfa)
• Smilax sp. (Sarpsarilla)
• Convalleria majalis (Lily of the Valley)