Evaluation of <i>Ocimum basilicum</i> L. with Different Concentrations of K⁺ as an Inhibitor of Pathogenic Bacterial Strains

The extraction of bioactive compounds has become one of the most interesting areas of modern chemistry. For therapeutic reasons, it´s important to obtain antimicrobial agents from natural origin. The objective of the present study was to determine the inhibitory effect of ethanolic extract of basil (Ocimum basilicum L. var. Red Rubin) subjected to different concentrations of potassium (K⁺) on the activity of three bacterial strains that are pathogens in humans. Susceptibility was evaluated by inhibition surface and these results were compared to two antibiotics: Gentamicin (GE) and Ciprofloxacin (CPF) for their efficacy against each bacterial strain. Analyzed variables presented significant difference (p ≤ 0.05). According to the results, basil extract evaluated showed positive antibacterial activity against the three strains of Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus on Mueller Hinton agar. It was observed highest inhibition areas of different diameters (15.3 mm, 21.3 mm and 21.6 mm respectively) when the extract used was obtained from the plants with the highest concentration of potassium (13 mmol L^–1). These values were even superior to the highest values showed on the treatments with the antibiotic gentamicin.