Data published in Scientific Reports (a Nature journal) showed that Kombucha-fermented Yerba Mate yielded a range of bioactives, including polyphenols such as chlorogenic acid or caffeoyl derivatives, plus xanthines and flavonoids.
The extracts were found to have anti-aging and anti-inflammatory properties, reported scientists from the University of Information Technology and Management in Rzeszow and the Medical University of Lublin.
These properties are “extremely important in the context of healthy skin appearance and prevention of various skin imperfections”, they wrote.
Kombucha & yerba mate
Kombucha is typically defined as a fermented tea, whereby firms brew tea, add sugar, and then ferment the mixture with a kombucha culture or 'SCOBY' (symbiotic culture of bacteria and yeast), which creates, among other things, carbon dioxide (explaining why kombucha is a bit fizzy), alcohol, acetic acid (explaining the slightly sour, vinegary taste) and other organic acids such as lactic acid, propionic acid, glucuronic acid and gluconic acid.
While the majority of kombucha is carried out using green or black tea, the researchers behind the new study examined the impacts of using a kombucha culture to ferment yerba mate (Illex paraguariensis), a tea-like drink traditionally consumed in South American countries by pouring boiling water onto a high concentration of leaves. The active ingredients of the beverage include polyphenols and caffeoyl derivatives, such as caffeic acid, chlorogenic acid, and different forms of dicaffeoylquinic acid. Yerba maté also contains phytosterols and saponins.
For the new study, the researchers used a commercial kombucha starter culture from a supplier in Poland to ferment Yerba Mate for different lengths of time. The fermented and unfermented extracts were then examined in terms of chemical composition and biological activity using skin cells (keratinocytes and fibroblasts).
The data revealed that the ferments, particularly those obtained after 14 and 21 days of fermentation, strongly inhibited the activity of enzymes such as collagenase and elastase, which “play an important role in the skin aging process through the degradation of collagen and elastin fibers”, explained the researchers.
In addition, the 14- and 21-day ferments were found to have long‐lasting hydration after application to the skin, said the researchers.
Chemical analysis of the ferments revealed the presence of compounds such as phenolic acids, xanthines and flavonoids.
“The presence of active substances, mainly polyphenols, such as chlorogenic acid or caffeoyl derivatives, as well as xanthines and flavonoids, may indicate a high antioxidant potential in both [Yerba Mate] extract and Kombucha ferments,” stated the researchers.
“The obtained results indicate that the ferments, apart from their probiotic activity supporting the beneficial microorganisms inhabiting the human skin, can also be a valuable ingredient present in pharmaceutical and cosmetic products,” they concluded.
Source: Scientific Reports
2021, 11, 18792, doi: 10.1038/s41598-021-98191-6
“Effect of fermentation time on the content of bioactive compounds with cosmetic and dermatological properties in Kombucha Yerba Mate extracts”
Authors: A. Ziemlewska, et al.