Antimicrobial activity of the essential oil from Hyptis carpinifolia Benth

Abstract

Essential oils are secondary metabolites whose biological properties have been studied with emphasis on antimicrobial activity. Hyptis carpinifolia Benth (Rosmaninho) is used in folk medicine in the fight against colds and rheumatism. The objective of this study was to evaluate the antimicrobial activity of the essential oil from H. carpinifolia. The essential oil was extracted by hydrodistillation using a modified Clevenger apparatus. The biological activity was determined using the Agar Cavity Diffusion technique to evaluate the effect of concentrations of 500, 250, 125, 62.5, 31.25, 15.62, 7.81 and 3.9 μg·mL-1 on the bacteria Escherichia coli, Listeria monocytogenes, Salmonella Choleraesuis, Staphylococcus aureus and Pseudomonas aeruginosa. The fungicidal potential was evaluated by the method of dilution in agar, and the percentage inhibition of mycelial growth of Alternaria alternata, Botrytis cinerea and Fusarium oxysporum was evaluated. The dilutions tested were 1000, 750, 500, 250 and 100 μL·L-1. The minimum inhibitory concentrations (MIC) of the essential oil for L. monocytogenes, S. aureus and E. coli were 31.25; 15.62 and 62.5 μg·mL-1, respectively. The MIC was 500 μg·mL-1 for Salmonella Choleraesuis and P. aeruginosa. The percentage inhibitions of mycelial growth of B. cinerea and A. alternate were 67% and 33%, respectively, at the dilution of 750 μL·L-1. The essential oil inhibited about 48% of the mycelial growth of F. oxysporum, at the dilution of 1000 μL·L-1. The essential oil of H. carpinifolia presented biological activity against all the microorganisms evaluated.