Schinus weinmanniifolia as a natural alternative for the control of skin infections: a multifactorial approach against methicillin-resistant Staphylococcus aureus

Schinus weinmanniifolia Mart. ex Engl. (aroeira-rasteira) is a native plant of Brazilian biodiversity. Among Indigenous peoples, the infusion of its leaves is used to relieve sore throats and inflammation. This practice reflects the reliance on traditional medicine in regions with limited access to conventional healthcare. To evaluate the antibacterial activity of the aqueous extract of S. weinmanniifolia leaves (AESW) against Staphylococcus aureus , including methicillin-resistant strains (MRSA), and its effects on bacterial biofilms. The extract was obtained by infusion and characterized by HPLC-DAD. The minimum inhibitory and bactericidal concentration assay, kill time, and enzymatic inhibition were performed, in addition to in vitro and ex vivo antibiofilm activity evaluations. AESW inhibited S. aureus and MRSA at concentrations ranging from 125 to 250 μg/mL and exhibited bactericidal effects at 250 μg/mL after 8 h of treatment. In addition, it reduced DNase and coagulase activities, indicating action on virulence factors associated with cutaneous pathogenesis. In antibiofilm assays, the extract inhibited up to 90% of biofilm formation and reduced the viability of mature biofilms by 70%. In the ex vivo biological model (porcine skin), it inhibited 96% of biofilm formation and reduced 99% of pre-established biofilms after 8 h of treatment. These effects were associated with the presence of gallic acid, a phenolic compound reported to possess antimicrobial potential. The extract proved to be a promising alternative for controlling S. aureus , including resistant strains, acting effectively against both planktonic cells and biofilms, reinforcing its therapeutic potential. • AESW showed bactericidal effect against S. aureus and MRSA after 8h of treatment. • It inhibited DNase and Coagulase virulence activities. • The extract interfered with cell adhesion during biofilm formation. • It reduced up to 99% of MRSA biofilms in an ex vivo porcine skin model after 8h of treatment.