In vitro Evaluation of Antimicrobial Activity from the Methanolic Extracts of Taraxacum officinale and Melissa officinalis on Staphylococcus aureus

The use of plants has been increasing by the presence of bioactives, which is an opportunity in the creation of products such as medicines, food and cosmetics. Taraxacum officinale (Dandelion) and Melissa officinalis (Toronjil), are cosmopolitan species with great therapeutic potential, traditionally used for their anti-inflammatory, antioxidant and antimicrobial activity. Therefore, this research evaluates the antimicrobial activity of the methanol extracts of Taraxacum officinale and Melissa officinalis on Staphylococcus aureus using in vitro tests. Analyzes of secondary metabolites were performed by phytochemical screening tests, as well as the identification of possible compounds responsible for antimicrobial activity using the Bioautography technique. The phenolic compounds were quantified by the Folin-Ciocalteu assay, and the antimicrobial capacity of the extracts was evaluated by the Kirby-Bauer method. Phytochemical screening revealed the presence of alkaloids, flavonoids, saponins, phenols and tannins in both extracts. Using Bioautography, potentially inhibitory metabolites were identified, including chlorogenic acid (Rf 0.45), taraxasterol (Rf 0.65), caffeic acid (Rf 0.87), geraniol (Rf 0.2), citral (0.42) and citronellal (0.8). In addition, a greater number of phenolic compounds (112.20 ± 10.13 mg EAG/g MS) was observed in the extract of Melissa officinalis, while the extract of Taraxacum officinale showed a greater bacterial inhibition capacity, reaching 65.49%.