Staphylococcus aureus/Staphylococcus epidermidis from skin microbiota are balanced by Pomegranate peel extract: An eco-sustainable approach

The imbalance in skin microbiota is characterized by an increased number of pathogens in respect to commensal microorganisms. Starting from a skin microbiota collection, the aim of this work was to evaluate the possible role of Pomegranate (Punica granatum L.) Peel Extract (PPE) in restoring the skin microbiota balance acting on Staphylococcus spp. PPE was extracted following green methodology by using n-butane and the Dimethyl Ether (DME) solvents and analyzed for phytochemical composition and antimicrobial activity. The PPE antimicrobial action was evaluated against Gram +, Gram - bacteria and yeast reference strains and the most effective extract was tested against the main skin microbiota isolated strains. PPE extracted with DME showed the best antimicrobial action with MICs ranging from 1 to 128 mg/mL; the main active compounds were Catechin, Quercetin, Vanillic acid and Gallic acid. The PPE in DME anti-adhesive effect was examined against S. epidermidis and S. aureus mono and dual-species biofilm formation by biomass quantification and CFU/mL determination. The extract toxicity was evaluated by using Galleria mellonella larvae in vivo model. The extract displayed a significant anti-adhesive activity with a remarkable species-specific action at 4 and 8 mg/mL against S. epidermidis and S. aureus mono and dual-species biofilms. PPE in DME could represent an eco-sustainable non-toxic strategy to affect the Staphylococcal skin colonization in a species-specific way. The innovation of this work is represented by the reuse of food waste to balance skin microbiota.