Chemical composition, antioxidant and antimicrobial activities of Lepechinia rufocampii Epling & Mathias essential oil from the highlands of Ecuado

Abstract

The chemical composition, antioxidant and antimicrobial activities of the essential oil from leaves and flowers of Lepechinia rufocampii Epling & Mathias were studied. GC-FID and GC-MS analyses allowed the identification and quantification of 122 constituents, representing 98.7% of the essential oil. Aliphatic compounds, mainly methyl ketones (62.4%) and sesquiterpene hydrocarbons (19.5%) were found to be the most abundant compounds, while oxygenated monoterpenes were the minor. The most abundant compounds were undecan-2-one (34.6%), nonan-2-one (21.1%), and (E)-caryophyllene (8.3%). Antioxidant activity was examined using DPPH, ABTS, and FRAP assays. The essential oil had a low scavenging effect and it showed ferric reducing activity. Antimicrobial activity of the essential oil was observed against pathogenic bacteria and a pathogenic yeast. The essential oil showed very good activity against Staphylococcus aureus, Escherichia coli and Salmonella enterica serovar, but low activities against Pseudomonas aeruginosa and Candida albicans. The MIC value of the essential oil varied from 1.04-33.05 µL/mL, with the lowest for Salmonella enterica serovar.