Very, very simply.
But first, the name Soap Nut is misleading for it is the shell that actually works. The soap nut SHELL contains and releases the saponins (soap) when it comes in contact with warm or hot water. Agitation further releases these saponins. The saponins then circulate as a natural surfactant (surface active ingredient). They break down the surface tension between water and oil in the wash water reducing the surface tension of the water aiding it in freeing dirt, grime and oils from clothes. Essentially this is the exact same fundamental principle that applies to how most detergents and soaps work. It's simply not achieved via the use of synthetic chemicals.
Buying these products, you support the environment, but also you can be free from chemicals at home.
100% Made with care & Love.