Naturally occurring steroid hormones owe their effect to their lipid solubility and ease of passing through membranes.
Human steroids possess the ability to bind or cross lipid
membranes due to their four-ringed non-polar structure.
Steroids are compounds that contain a backbone of four (tetracyclic) carbon ring structures fused along one side. This is the classic steroid backbone from which a variety of sugars and small chains are draped. The addition of these groups at different sites on the backbone leads to the limited variety of steroidal compounds.
Plant sterols are more diverse than their human counterparts, steroids. Yet, their basic structure (5 carbon rings) is very similar to the 4 carbon ring structure of human steroids. In both sets of compounds, the carbon rings provide an organic matrix that gives them their chemical consistency. It is this consistency that allows steroids and saponins to move through similarly structured materials (membranes).
Plant saponins structurally resemble steroid hormones but
are built upon 5 carbon rings instead. This similarity explains why they are capable of causing similar effects. to steroids. They both cross cell membranes without the need of carriers. The additional cyclic group causes them to foam when mixed with water.
These minor substitutions represent the only diversity permitted within steroid hormones. As steroids, their lipid solubility allows them access to the nucleus where they interact with DNA to produce their effects.
Traditional Medicine is founded on the use of local plants. Village healers extracted substances from local plants and gave them to their villagers to restore harmony and balance. These plants contain a class of phytochemical known as saponins. Saponins are named due to their tendency to form a lather. Saponins are a plant’s version of a steroid.
Steroids and saponins are both lipid soluble compounds that can cross the lipid rich barrier of membranes. They both bind with membrane receptors, steroid carriers and genes. Each of them is capable of producing effects on various processes.
Saponins are lipid structures responsible for the effects of herbs. Saponins or plant sterols are lipid soluble compounds that like human steroids have the ability to cross cell membranes. Once inside the cell, saponins act like steroids to direct DNA activity.
Saponins bind with receptors to form complexes just as human steroid hormones. The saponin complex, just as the steroid complex, interacts directly with genes (DNA) to produce their intended effects.
Unlike neurotransmitters or metabolic hormones, whose effects are instantaneous, steroids require time to produce their effects. The effects produced by saponins are likewise long term.
For example, the use of the herb ginseng in males and dang qui in females provides longevity and resistance to illness only with long term, regular consumption.
Some saponins, like those found in ginseng, interact with the adrenal cortex to promote hormonal efficiency. This helps cope with stress and is one of the reasons ginseng is so highly recommended.
Plant saponins complexed with sugar molecules are termed glycosides. It is in this form that they are active. Since saponins and their glycosides are found in plants with no known function for the plant, it is believed that the actions of these substances are intended to ward off the plant’s natural predators. In other words, these compounds can be harmful but may also offer unknown medicinal benefits.
A saponin is classified on the basis of its carbohydrate content and its sapogenin or triterpene core core. The activity of any given molecule is dependent on its core structure while selectivity is a function of the sugar alignment as part of the whole complex.
The core of a saponin is a structure made up of five carbon rings. A sapogenin’s core is the equivalent of the backbone of a steroid. From the sapogenin core, different sugars are complexed providing the plant with its library of similarly structured compounds. This determines the binding specificity of the molecule.
Each member of the library is thus slightly unique and will therefore bind with a different membrane receptor. Saponins are triterpene glycosides with varying number of sugar side chains. These compounds are synthesized by plants and are the basis for many wonder drugs such as the cardiac glycosides.
A plant sterol is built upon its triterpene core. The triterpene and the steroid are remarkably similar in structure and function. Steroid diversity is limited while Saponins or plant steroids exist in a variety of conformations. They are part of nature’s library, a library of diversity.
Diversity in the library occurs by the addition of one or more sugar molecules to the sapogenin core.