An aqueous watercress extract with topical anti-inflammatory properties in inflamed human skin
Watercress (Nasturtium officinale) is a species of the Brassicaceae plant family, with a biochemical composition which suggests potential uses in anti-inflammatory skincare applications. Watercress has a high content of both anti-inflammatory compounds (e.g., polyphenols) and compounds which upregulate the Nrf2-mediated antioxidant gene response (e.g., isothiocyanates) in human tissues. We have developed a process to manufacture an aqueous watercress extract that contains isothiocyanates and flavonoid-type polyphenols, some of which are known anti-inflammatory compounds. We partially characterized the chemical composition of our extract (LC-QTOF-MS), and we demonstrated in a cultured full-thickness human skin model, that the extract was non-cytotoxic and non-irritant, as monitored by cell viability and IL1 concentrations, respectively. In human trials, in vivo, we showed by visual clinical scoring of inflammation that the extract had anti-inflammatory properties. The anti-inflammatory properties of the aqueous watercress extract may provide a treatment for inflammatory skin diseases such as eczema.