Submitted:
22 December 2025
Posted:
24 December 2025
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Abstract
Medicinal plants have become increasingly important due to the diversity and bactericidal potential of many species. They can work as an alternative to the use of antimicrobials in the treatment of bacterial infections, which may represent impairment to health. Considering the importance of alternative compounds, we aimed to evaluate the antimicrobial activity in vitro of medicinal plants Stryphnodendron adstringens (Mart.) Coville, known as barbatimão, Baccharis crispa Spreng, known as carqueja and Azadiractha indica, known as neem. S. adstringens and B. crispa were used as extract and obtained from plants collected in the municipality of Bambuí, state of Minas Gerais, Brazil. A. indica was evaluated as extract and oil, and the crushed leaves and oil were purchased from a commercial company. Antimicrobial activity was determined by the minimum bactericidal concentration (MBC) test against Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, Escherichia coli, and Salmonella spp, isolated from bovine mastitis. The bacteria were submitted to the MBC test at concentrations of 100, 50, 25, 12.5, 6.25, 3.12, 1.56, 0.78, 0.39, 0.19 and 0.09 mg/mL. The bacteria evaluated were sensitive to most plant extracts for at least one of the concentrations evaluated, except for Gram-negative bacteria, Escherichia coli, and Salmonella spp. There was no activity of B. crispa extract and A. indica against E. coli and neither of A. indica extract against Salmonella spp. even at the highest concentration evaluated. S. adstringens was considered the extract with the highest activity against the bacteria evaluated and S. uberis the most susceptible to antimicrobial action. The results indicate the antimicrobial activity of the compounds and a possible application of these for the development of biotechnological products against the main bacteria causing bovine mastitis, becoming an alternative to the use of antibiotics.
