A remarkably cleansing compound

What are saponins and what properties do they have?

Saponins are bioactive compounds that occur mainly in plant tissues and belong to the group of plant secondary metabolites. They consist of a sugar portion and an aglycone and are characterised by their ability to reduce the surface tension of water. This enables them to form a soap-like foam and to solubilise various substances. Saponins are both lipophilic and hydrophilic, which gives them these unique properties.

What role do saponins play in plant protection?

Saponins play a crucial role as plant defence compounds against herbivores and pathogens. Their effectiveness against fungal infestations is particularly noteworthy. This effect is based on direct damage to the cell membranes of pathogens, leading to their death. In addition, the surfactant substances can alter the surface of plant organs so that fungal spores cannot attach in the first place. Plant extracts containing saponins therefore prove to be effective natural crop protection agents.

What therapeutic effects do saponins have?

Saponins are important therapeutically active constituents of medicinal plants. Their structural diversity leads to a range of biological and pharmacological properties, including tonic, anti-inflammatory, diuretic, expectorant and hormone-stimulating effects.

They promote the absorption of nutrients from the gut and help to bind cholesterol. It is also suspected that saponins may have a preventive effect against colorectal cancer by inhibiting cell division in the gut. Certain saponins can regulate the hormonal system and help in cases of testosterone deficiency.

Which plants contain saponins and what precautions should be taken?

Saponins are mainly found in nutrient-rich plant parts such as roots, flowers, leaves, tubers and seeds. Saponin content often increases under stress conditions such as drought or in the presence of pathogens. Particularly high concentrations are found in various legumes such as chickpeas, soybeans, alfalfa and kidney beans. Vegetables such as spinach, asparagus and yam as well as pseudocereals like quinoa are also rich in saponins.

Care should be taken when using saponins, as at high concentrations they can cause health problems, such as a haemolytic reaction in which blood cells are destroyed.

What potential side effects and usage limitations do saponins have?

At higher doses, saponins can have an emetic effect, i.e. cause nausea and vomiting. At lower doses they act as an expectorant by triggering irritant reactions in the upper digestive tract. They cause the body to produce more of the thin mucus that lines the cells of the airways and reduce mucus viscosity, which facilitates expectoration.

A notable saponin is glycyrrhizin, which occurs in licorice and can lead to disturbances of mineral metabolism when consumed in excess.

Sustainable cleaning options with natural plant saponins

• Use natural surfactants such as plant saponins for environmentally friendly washing. They not only clean clothes effectively but also protect the environment, as they are biodegradable and do not contain harmful chemicals.
• Use soapwort or washing nuts as an alternative to conventional detergents. 
• Collect horse chestnuts in autumn to use as a washing agent. Chop and dry them carefully. Then pour a handful of the chopped chestnuts over one litre of water. After a steeping time of 5 minutes, pour off the decoction and use it directly as a liquid detergent. Chestnuts contain natural saponins that effectively remove dirt and stains. This way you not only save money but also protect the environment.
• Consider ivy leaves as well, which also contain saponins and are a good alternative to conventional detergents. Ivy is a widespread plant available year-round.
• Make sure that the collected chestnuts or ivy leaves are clean and free from mould.
• Use plant-based detergents for light soiling or delicate textiles, but note that they are not as effective as conventional detergents for heavy contamination. You can pre-treat stains before washing to achieve better results.
• Be aware of the short shelf life of homemade chestnut or ivy solutions and only make as much as you will use in a short time.
• Soak a handful of horse chestnuts or birch leaves in water to make liquid soap. Let the mixture stand for several hours so that the saponins are released from the plants and the water foams.
• Moisten some birch leaves with water and rub them until they foam if you only want to wash your hands. This method is particularly suitable when you are on the go and do not have time to prepare liquid soap.
• Boil washing nuts in water to make a decoction that can be used as a body wash, hair shampoo or even as a mild all-purpose household cleaner. This decoction also has good activity against various plant-pathogenic fungi.
• Use washing nuts as dishwashing detergent by placing them in a small bag directly in the cutlery basket of the dishwasher. 
• Use saponin complexes for thorough and gentle skin cleansing. They have antibacterial, immune-stimulating properties and can even dissolve fats.
• Note that saponins reduce the surface tension of water and can enhance the skin's absorption capacity. This makes other ingredients in plant-based cosmetics more effective.
• Use saponins such as glycine saponin from soybeans to stimulate the body's own production of hyaluronic acid. This can help combat signs of skin ageing and deep wrinkles. Soybeans can be eaten raw or prepared. To obtain saponins from soybeans, however, they must be extracted. This typically requires specialised techniques or solvents to isolate the saponins from the beans.

Saponins are fascinating natural compounds from the plant world and have a wide range of applications and benefits. They represent a sustainable alternative to industrially produced chemical products. Their diverse properties and natural origin make them valuable components of an ecological lifestyle.