Essential oil of Minthostachys mollis [HBK] Griseb. leaves from Ecuador: Extraction, chemical composition, antioxidant capacity and antimicrobial activity

Abstract

The aim of this study was to optimize by response surface design, the extraction of the leaf essential oil (EO) from Minthostachys mollis [HBK] Griseb., grown in Ecuador, using steam distillation. The factors used were extraction time (XTIE) of 60, 105 and 150 min and plant material/water ratio (XRMA) of 1:3, 1:4 and 1:5. The optimal combination was reached with XRMA 1:5 and XTIE 150 min, obtaining a process yield of 0.67%. The chemical composition of the EO analyzed by GC-MS was determined, where the main compounds were carvacryl acetate (44.01%), carvacrol (16.51%) and menthone (8.20%). The antioxidant capacity of EO was evaluated using the FRAP and ABTS methodologies, with an IC50 243.21 µmol Fe2+/g and 0.12 mg/mL, respectively. In addition, the antimicrobial activity of EO was found against Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Staphylococcus aureus.