Evaluation of the Antibacterial Activity of Chilean Plants Traditionally Used for Wound Healing Therapy against Multidrug-Resistant Staphylococcus aureus

Anti-staphylococcal activity of Chilean medicinal plants traditionally used by the Huilliche people for wound healing therapy was evaluated against nine Staphylococcus aureus strains. Three extracts of 26 plant samples (20 species) were evaluated by agar overlay bioautography and MIC determination. Total phenolics and tannins were determined, and the antibacterial contribution of the latter was evaluated. The diffusion assay showed that 17 species were active against susceptible S. aureus and that 15 species were active against resistant S. aureus. Removal of tannins from extracts rendered only six species active. MIC-determination showed that 20 extracts had antibacterial activity on all eight strains, and the most potent MIC value was 64 mu g/mL. Remarkably, 37 extracts were active against the otherwise multidrug-resistant vanthida strain. Our findings support the wound healing properties of Huilliche medicinal plants and the hypothesis that these plants are promising sources of potential antistaphylococcal agents towards multidrug-resistant strains.