How is the duckweed obtained?

An aquatic plant still relatively unknown to the general public, the spirodela, or Spirodela polyrhiza, is garnering increasing interest in the skincare industry. This water lentil, naturally found on the surface of ponds or stagnant waters, contains phenolic compounds and flavonoids, which have antioxidant and soothing properties. It is particularly rich in apiogalacturonans, pectins known for their hydrating virtues. Thanks to its anti-inflammatory effects, spirodela is now considered for soothing sensitive skin or skin prone to eczema. Moreover, its plant origin makes it an attractive ingredient in a context where the naturalness of a formula is increasingly important to consumers.

The scientific literature describing the extraction of the Spirodela polyrhiza is currently quite sparse.

However, it appears that the duckweed used in skincare is obtained in the following manner. The first step relies on a concentrated solubilisation of the plant in water, at a concentration of at least 50 g/L, in order to achieve a sufficiently rich base for subsequent treatments. This plant solution is then subjected to a chemical hydrolysis of an acidic nature, sometimes combined with an enzymatic hydrolysis.

These hydrolysis stages are crucial: by breaking the bonds between the complex components of cell walls, they enable the release of active molecules from the duckweed trapped within the plant structure, particularly the apiogalacturonans mentioned earlier for their hygroscopic potential. The hydrolysis stages also contribute to solubilising other actives, such as flavonoids, while facilitating the removal of unwanted insoluble residues. Once the hydrolyses are carried out, the soluble and insoluble fractions are separated, in order to only retain the aqueous phase containing the sought-after molecules.

The soluble phase is then collected and subjected to a thermal treatment. This step aims to inactivate certain enzymatic residues and stabilise the extracts. This is followed by stages of purification and concentration, which serve to eliminate potential contaminants while standardising the content of active ingredients. Finally, the solution undergoes a sterilising filtration, ensuring the absence of germs, a crucial condition given its water content for use in a skincare product intended for the skin.