NEW LIFE FOR VITIS VINIFERA L. LEAVES EXTRACTS THROUGH PROBIOTIC-MEDIATED FERMENTATION: INVESTIGATING THEIR ANTIMICROBIAL POTENTIAL TOWARDS METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS

Staphylococcus aureus is a skin pathobiont that in dysbiotic conditions may contribute to infections, barrier integrity loss, skin aging, and inflammation1 . Due to the spread of multidrug resistant strains like methicillinresistant S. aureus (MRSA) ones, new alternative preventive and therapeutic approaches are needed. In this scenario, plant waste like Vitis vinifera L. leaves extracts (VVLEs) and derived fermented extracts (fVVLEs) could exert antioxidant, anti-inflammatory, and antipathogen potential2,3 . Starting from these findings, we compared VVLEs and fVVLEs in terms of: i) analytic profile (i.e., total phenol content and lactic acid content quantification); ii) antioxidant activity (DPPH assay); iii) in vitro antipathogen potential towards MRSA ATCC 43300 viability (e.g., alamarBlue assay). Both the products are rich in polyphenols and have good antioxidant activity. Moreover, fVVLEs show high lactic acid levels. Comparing VVLEs and fVVLEs effects on MRSA, data show their different degree of antimicrobial potential. Overall, exploitation of grape biomasses satisfies the standards required by the green circular economy model, while providing new alternatives to manage MRSA global burden. Further investigations are needed for their future possible use in the management of dysbiosis-associated skin issues.