Antimicrobial Activities of Essential Oils of Mint and Peppermint as Well as Some of Their Main Compounds

摘要

The oil of peppermint (Mentha x piperita L.) from the USA,a dementholized cornmint oil (M. canadensis L.),and a fraction of the dementholized cornmint oil were analyzed by GC-FID and GC/MS. The main constituents of the three samples analyzed were menthone (23.4%,20.4% and 58.3%,respectively) and menthol (40.7%,41.2% and 12.3%,respectively). The two oils,the cornmint oil fraction and seven mint oil compounds [(-)-menthol,(-)-menthone,(+/-)-menthyl acetate,1,8-cineole,limonene,beta-pinene and beta-caryophyllene] were investigated for their antimicrobial effects against two Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis),five Gram-negative bacteria (Escherichia coli,Pseudonwnas aeruginosa,Proteus vulgaris,Klebsiella pneumoniae and Salmonella sp.) and the yeast Candida albicans using a modified agar dilution and agar diffusion method. Medium to high antimicrobial effects were found for both oils,the dementholized cornmint oil fraction,and the target-compounds against all Gram-positive bacteria,whereas against the Gram-negative bacteria and the yeast,one or more samples showed only weak or no activity.