GMB

“Sapo” in Latin means soap, and the cover image for this week’s leaf shows fruits of Sapindus, the soapberry or soapnut tree. So-called “natural” soaps are widely available for purchase from stores and online sellers, but almost all of them are actually man-made, albeit from natural ingredients. However, saponins are the real thing, detergent moleculesmade by plants all on their own.

As we all know, oil and water don’t mix! Most compounds prefer either oil (lipophiles) or water (hydrophiles). Detergents arecompounds with lipophilic and hydrophilic domains at either end. This is why they can disperse oils and fats in water. In saponins, the hydrophilic end isusually some sort of sugar and the hydrophobic end a phenolic group such as aterpenoid or steroid.

Natural saponins are often bittertasting, and may serve the plant by deterring grazing animals. Additionally, somesaponins may have antibacterial, antifungal and insecticidal effects. Most saponins are toxic to fish, and saponin-rich plants have thus been used for fishing by indigenous peoples in several parts of the world. Some saponins are highly toxic to humans, e.g. solanine from the deadly nightshade plant.

However, there are a number of saponins that are safe for use in pharmaceuticals, cosmetics, food and beverages. Forexample, Quillaia extract from the “soapbark” tree is used to put a nice foamy head on carbonated beverages.

Sapindus extract is one that we at Green Mountain Biotech manufacture for use in skincare and haircare products. This extract is very rich in a saponin called hederin that produces a nice lather and has useful antimicrobial properties.

So next time you take a bath or shower (or drink a root beer), take a pause to remind yourself that plants knew all about making detergents long before humans began making soap!