In vitro evaluation of enzymatically derived blackcurrant extract as prebiotic cosmetic ingredient: extraction conditions optimization and effect on cutaneous microbiota representatives

Abstract

Background Blackcurrant is a rich source of polyphenols with proven physiological activity, that have lately been classified as emerging prebiotics, making its extracts suitable for application in functional food and bioactive cosmetics. However, these biomolecules are trapped in cell wall structures and nowadays, enzymatic hydrolysis is recognised as powerful tool for extraction efficiency improvement in an environmentally sound manner. This study aimed to optimize enzyme-assisted extraction to maximize yields of blackcurrant polyphenols. In addition, their prebiotic potential was tested by examining their influence on typical skin microbiota representatives as model microorganisms—beneficial coagulase-negative Staphylococcus epidermidis and two opportunistic pathogens, Staphylococcus aureus and Cutibacterium acnes. Results Among four examined commercial enzyme preparations, Viscozyme® L and Rohapect® MC, demonstrated the highest potential as extraction enhancers by increasing antioxidant activity, total polyphenol, and flavonoid contents. Furthermore, their synergetic effect enabled 95.3% increase in polyphenol concentration compared to conventional extraction with a maximum of 27.6 mg gallic acid equivalents (GAE)/g dry matter (DM) at a total enzyme concentration of 0.05 mL/g DM (Viscozyme® L to Rohapect® MC ratio 2:1) after 60 min. HPLC profiles of two samples showed differences in polyphenol composition indicating simultaneous extraction–biotransformation. At a concentration of 0.025 mg GAE/mL, PAS (prebiotic activity score) values were 0.096 and 0.172 for conventionally and enzymatically obtained extract, respectively. Moderate inhibitory effect of optimal extract concentration on Cutibacterium acnes was shown, as well. Hydrogel prepared with optimal extract concentration showed improved hydration effect, decreased irritability and increased dermatological compatibility comparing to basic formulation. Conclusions Overall results demonstrated that blackcurrant extract obtained under optimized conditions using enzymes possesses an emerging prebiotic potential for selective skin microbiota stimulation.