Saponins – Function & Diseases
saponins
Saponins are soapy compounds that are only found in plants. The individual molecules consist of a hydrophilic and a lipophilic part. Their structures, properties and modes of action are very diverse.
What are saponins?
Saponins are biological compounds that are only formed in plant tissues. They represent secondary plant substances. They are also subject to a large structural diversity. In their basic structure, they consist of a sugar part and a non-sugar component (aglycon) in the molecule.
The sugar portion is glycosidically bound to the aglycone. The sugar or carbohydrate components are usually made up of chains of D-glucose, D-fructose, D-galactose, D-glucuronic acid or other sugar building blocks. Three different structural components can serve as aglycones. These are the steroids , steroid alkaloids or terpenes. The aglycones form the lipophilic part and the sugar components form the hydrophilic part of the molecule. Because the molecule has both lipophilic and hydrophilic properties, it can lower the surface tension of water. It therefore foams in water and brings different compounds into solution.
With the help of the saponins, fat-soluble substances are also brought into an aqueous solution. So saponins are surfactants and appear soapy. The term saponin comes from Latin and means soap. In the plant, saponins usually have a fungicidal or antibacterial effect. Due to the similar structure of the sterols found in fungal membranes, larger molecular complexes can form, which ensure the formation of pores within the fungal membranes. This destroys the fungal cells. Antibacterial saponins have a similar effect.
Function, effect & tasks
For humans, only the saponins found in plant foods play a major role. Due to their great structural diversity, the mode of action of the individual saponins is different and often still unexplored.
Mostly they have positive qualities or are neutral. In rarer cases, toxic effects have also become known. For plants, they mean defensive active ingredients that act against fungi, bacteria and insects. The lack of an active immune system in plants makes it necessary for them to develop chemical defense mechanisms. However, some saponins also develop clear positive health effects in humans and animals, so that they play an important role in herbal medicine. Depending on the structural composition of individual saponins, anti-inflammatory, strengthening, expectorant, diuretic or hormone-stimulating properties of this group of substances have been discovered.
Due to their special structure, saponins can also bind cholesterol and thus contribute to lowering the cholesterol level. At the same time, there are studies that indicate a preventive effect of saponins against colon cancer by having an inhibitory effect on cell division. However, many medical influences are not yet fully understood and require further investigation. In addition to cholesterol-lowering effects, saponins also have blood pressure-increasing effects and can therefore be used for low blood pressure . Also immune modulating influences are observed.
Formation, Occurrence, Properties & Optimal Values
As already mentioned, saponins are only found in plant tissue. There they are mainly found in particularly nutrient-rich plant parts. These include roots, flowers, leaves, tubers or seeds. Tomatoes , potatoes , peas , soybeans and spinach are particularly rich in saponins . Certain herbs have a positive health effect precisely because of the saponins they contain, such as ginseng or certain types of tea.
Chestnuts also contain high concentrations of saponins. In the past, the juice from the roots of soapwort was used as a detergent because of the saponins it contained. The formation of saponins occurs through a glycosidic connection of aglycones, which mainly consist of a steroid or terpene basic structure, with a carbohydrate component. The aglycones do not have any polar functional groups, so this molecule component dissolves in fat-like substances. The carbohydrate portion contains many hydroxyl groups which induce intense water solubility of this part of the molecule.
Because of this fact, saponins are good solubilizers. They enable many substances to overcome the phase boundary between two immiscible components. This also explains the interaction of saponins with membrane components of various microorganisms such as bacteria or fungi. The most important suppliers of saponins for medicinal purposes are legumes, asparagus , sugar beets , beetroot, horse chestnuts and daisies .
Diseases & Disorders
In addition to positive effects, taking saponins can also lead to health problems. However, this usually requires very high concentrations, which cannot be reached even when consuming foods with a high saponin content. However, when saponins come into contact with the bloodstream, even lower concentrations are sufficient to trigger haemolysis .
As a rule, this is only a hemolytic effect, in which blood cells are dissolved due to their interaction with saponins. This fact is used in blood tests, among other things, as a quantitative standard method. If the intestinal wall is inflamed, the influence of saponins can increase the permeability of the intestinal wall. Overall, however, the amounts supplied through food are rarely sufficient for such an effect. However, certain side effects can occur when consuming licorice .
Licorice contains large amounts of glycyrrhizic acid. This is a saponin found in the root of the licorice plant . Liquorice is made from the liquorice plant. Glycyrrhizic acid inhibits the formation of cortisone from cortisol. Cortisone is the inactive form of the hormone. The active cortisol unspecifically occupies the mineralocorticoid receptors and produces effects similar to those of the mineralocorticoid hormone aldosterone . The mineral metabolism becomes unbalanced in the form of fluid retention, hypokalemia and hypertension, a phenomenon that can occur with increased consumption of liquorice.
Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.