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:
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.