Effect of fermentation time on the content of bioactive compounds with cosmetic and dermatological properties in Kombucha Yerba Mate extracts

Kombucha is a beverage made by fermenting sugared tea using a symbiotic culture of bacteria belonging to the genus Acetobacter, Gluconobacter, and the yeasts of the genus Saccharomyces along with glucuronic acid, which has health-promoting properties. The paper presents the evaluation of ferments as a potential cosmetic raw material obtained from Yerba Mate after different fermentation times with the addition of Kombucha. Fermented and unfermented extracts were compared in terms of chemical composition and biological activity. The antioxidant potential of obtained ferments was analyzed by evaluating the scavenging of external and intracellular free radicals. Cytotoxicity was determined on keratinocyte and fibroblast cell lines, resulting in significant increase in cell viability for the ferments. The ferments, especially after 14 and 21 days of fermentation showed strong ability to inhibit (about 40% for F21) the activity of lipoxygenase, collagenase and elastase enzymes and long‐lasting hydration after their application on the skin. Moreover, active chemical compounds, including phenolic acids, xanthines and flavonoids were identified by HPLC/ESI–MS. The results showed that both the analyzed Yerba Mate extract and the ferments obtained with Kombucha may be valuable ingredients in cosmetic products.