Chemical and antibacterial evaluation of the essential oil from the leaves, petals and calyx of Calea phyllolepis Baker in Brazil

Abstract

In the face of the complex context of resistance of human pathogenic bacteria, essential oils act in a synergistic way preventing the bacterial mechanism to create resistance. This article brings the chemical identification of the essential oils of the leaves, petals, and calyx of C. phyllolepis and the evaluation of these in the control of S. aureus and E. coli (Minimum Inhibitory Concentration (MIC) and Disc Diffusion). Thirteen compounds were identified in the EOs, being five monoterpenes and eight sesquiterpenes. Sabinene, (-)-α-Pinene and ρ-Cymene presented with high concentrations in all the evaluated parts. The minimum concentrations to effectively inhibit the development of bacteria varied between 0.3% to 4.0% against S. aureus and 0.3% to 8.0% for E. coli in the colorimetric assay. The most effective action against the bacteria studied were found for petal and calyx EOs, which presented MICs of 0.063% and 0.03%, respectively. In the study with the disk diffusion method, a halo of inhibition higher than that of the control groups was obtained. The effectiveness of the oils against the treated microorganisms, can be correlated with the chemical composition. The study with this plant is unprecedented and the results obtained are promising in the search for new antibacterial products