Minimum inhibitory concentrations of medicinal plants used in Northern Peru as antibacterial remedies

Objectives: The aim of this study was to evaluate the minimum inhibitory concentration (MIC) of their antibacterial properties against Gram-positive and Gram-negative bacteria. Methods: The antimicrobial activity of ethanolic and aqueous extracts of 141 plant species was determined using a deep-well broth microdilution method on commercially available bacterial strains. Results: The ethanolic extracts of 51 species inhibited Escherichia coli, and 114 ethanolic extracts inhibited Staphylococcus aureus. In contrast, only 30 aqueous extracts showed activity against Escherichia coli and 38 extracts against Staphylococcus aureus. The MIC concentrations ranged from 0.008 to 256 mg/ml. Conclusions: The presence of antibacterial activity could be confirmed in medicinal plants used Peru for the treatment of bacterial infections. The MIC for most species employed showed a large range. Traditional knowledge provides leads to elucidate candidates for future antibiotic agent development. Study area: Peruvian Departments of Amazonas, Piura, Lambayeque, La Libertad, Cajamarca, San Martin, and the Ecuadorian Province of Loja. The plant species reported here are traditionally used in Northern Peru to treat bacterial infections, often addressed by the local healers as “inflammation”. The aim of this study was to evaluate the minimum inhibitory concentration (MIC) of their antibacterial properties against Gram-positive and Gram-negative bacteria. The antimicrobial activity of ethanolic and water extracts of 141 plant species was determined using a deep-well broth microdilution method on commercially available bacterial strains. The ethanolic extracts of 51 species inhibited Escherichia coli, and 114 ethanolic extracts inhibited Staphylococcus aureus. In contrast, only 30 aqueous extracts showed activity against Escherichia coli and 38 extracts against Staphylococcus aureus. The MIC concentrations were mostly very high and ranged from 0.008 to 256 mg/ml, with only 36 species showing inhibitory concentrations of