Saponins

Saponins are natural washing raw materials. Saponins owe their name (sapo lat. for soap) to their ability to foam in water like soap. Saponins are bitter tasting, glycosidic compounds that are widely found in many higher plants. Saponins have been found in > 90 plant families. Saponins complex cholesterol. Triterpenes, steroids or steroid alkaloids (nitrogenous steroids) form the basic structure of saponins.

In this respect a distinction is made between:

• Triterpene sapogenins (accumulate e.g. in horse chestnuts and primula species).
• Steroid sapogenins (are mainly found in roots, seeds and tubers).
• Steroidal alkaloidal sapogenins (are found, for example, in nightshade plants such as tomatoes and potatoes).

The substance group of saponins is very extensive due to the large number of possible carbohydrate structures and the great structural variability. This also results in great variability in the biological properties. Saponins usually form stable foams. One of their most important toxic properties is their haemolytic activity. When taken parenterally, all saponins have a toxic, possibly lethal effect. Saponins are highly toxic to fish because their surface activity inhibits gill functions.

Remark: The foaming and purifying functions of saponins have been known for centuries. The names of the South American soap bark tree, the Indian soap nuts and the soapwort (Saponaria officinalis) indicate these known functions (see also saponin drugs).

Aescin, a saponin mixture of the horse chestnut has a superficial vasotonic effect. Aescin is widely used for medical purposes in venous diseases.
Alpha hederin, hederacoside B and C (ivy extracts) have vasoconstrictive and anti-edematous effects.
Ruscogenin (kigelia extracts) contain steroidal saponins; they are said to have vasoconstrictive and vasoprotective effects.
Ruscin, ruscogenin and neo-ruscogenin, saponins of butcher's broom (Ruscus aculeatus) have astringent, tissue tightening and vasoprotective effects.
Equisetonin a saponin of the field horsetail (Equisetum arvense) has astringent, tissue-tightening and vasodilatory effects.
Glycyrrhizin, the saponin from the liquorice root (Glycyrrhiza glabra), unlike most other saponins, tastes sweet (component of liquorice). Glycyrrhizin has an anti-inflammatory effect.

Probably saponins are used by plants as antibodies against fungal attack and insect pests (Note: plants do not have an active immune system, so they have to organize their defense strategies with poisons). When nightshade plants such as tomatoes and potatoes ripen, the toxic steroidal alkaloidal saponins responsible for the green colour of fruits and tubers (e.g. solanine) are converted enzymatically into non-toxic steroidal saponins.

Saponins (see also saponin drugs) have been shown to have a number of pharmacological properties such as: analgesic, antiviral, antitumoral, neuroprotective, cardiovascular, immunomodulatory, sedative properties. However, their indications are essentially limited to their use as expectorants, vein therapeutics and geriatrics(Panax ginseng). Furthermore, they have neuroprotective effects.

Saponins are a component of the Liquor carbonis detergens through the addition of soap bark.

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5. Yang X et al (2014) Protective effects of panax notoginsengsaponins on cardiovascular diseases: a comprehensive overview of experimentalstudies. Evid Based Complement Alternat Med doi:10.1155/2014/204840