Chemical Composition and in vivo Efficacy of the Essential Oil of Mentha piperita L. in the Suppression of Crown Gall Disease on Tomato Plants.

This study was undertaken to determine the antibacterial efficacy of the essential oil (EO) of peppermint (Mentha piperita L.), in vitro and in vivo, against the phytopathogenic bacteria Agrobacterium tumefaciens (A. tumefaciens). The EO composition of M. piperita L. was investigated by Gas chromatography-mass spectrometry (GC/MS) with 26 identified volatile constituents. The major constituents were menthol (33.59%) and iso-menthone (33.00%). This EO exerted a bactericidal activity against multiple strains of Agrobacterium species with minimum inhibitory concentration (MIC) values ranged from 0.01 to 12.50 mg/mL. In planta experiments, M. piperita EO, tested at concentration of 200 mg/mL, completely inhibited the formation of tumors on tomato plants inoculated with pathogenic strain A. tumefaciens ATCC 23308^T. These results suggest that M. piperita EO could be used to control plant bacterial disease caused by A. tumefaciens.