Staphylococcus aureus is a Gram-positive bacterium present in the human microbiota, responsible for causing various skin infections, ranging from folliculitis to complex and painful abscesses. With the growing increase in bacterial resistance to previously developed drugs, the development of new agents capable of inhibiting these microorganisms has become a global public health priority. In this context, the use of plants with medicinal properties in the formulation of antimicrobials is considered a promising alternative. Many plants have perfected natural defense mechanisms, producing a variety of bioactive secondary metabolites. The species Vismia brasiliensis is native to Brazil, found mainly in the Atlantic Forest and Cerrado regions. Its medicinal properties stand out for their antioxidant, antimicrobial, and healing activities, which are attributed to the presence of bioactive compounds such as flavonoids and naphthoquinones. The objective of this study was to evaluate the antimicrobial activity of the crude extract of Vismia brasiliensis, to be used in a topical formulation aimed at the treatment of skin infections caused by Staphylococcus aureus.

Crude extracts from the stem (AM-151C), leaves (AM-151F), and inflorescences (AM-151INF) were evaluated to determine the minimum inhibitory concentration (MIC) against S. aureus (ATCC 25923), in triplicate, by the broth microdilution method. The samples were concentrated and solubilized in DMSO at 50 mg/mL and then tested at concentrations from 7.8125 to 500 µg/mL. The MIC was defined as the lowest concentration of the samples capable of inhibiting at least 70% of microbial growth.

The samples that showed the most relevant inhibition results were those from inflorescences (AM-151INF) with an MIC of 250 µg/mL (97.6 ± 0.1%) and from the stem (AM-151C) with an MIC of 500 µg/mL (92.9 ± 1.0%). The sample from the leaves (AM-151F) was not considered active against S. aureus.

The results show a strong antimicrobial potential of Vismia brasiliensis as an alternative to be employed in the development of topical formulations for the treatment of skin infections caused by Staphylococcus aureus.