Composition of volatile compounds and in vitro antimicrobial activity of nine Mentha spp.

Background: Mentha plants containing over 25 species are aromatic perennial herbs. These species have been interested and widely used because of various clinical findings. Many volatile compounds facilitate environmental interactions such as protecting themselves from pathogens, parasites, and herbivores. Therefore, this study assessed comparison of volatile composition and antimicrobial activity from nine Mentha species. The composition of volatiles was investigated from the aerial parts of nine different Mentha species using gas chromatography-mass spectrometry (GC/MS). In addition, screened antimicrobial activities against six food borne pathogenic bacteria using extracts obtained these plants. Results: 77 volatile compounds were identified in total and it included 13 monoterpenoids, 19 sesquiterpenoids, and others. In particular, monoterpenoids such as eucalyptol (9.35-62.16 %), (+/-) camphorquinone (1.50-51.61 %), and menthol (0.83-36.91 %) were mostly detected as major constituents in Mentha species. The ethanol extract of nine Mentha species showed higher activity compared to other solvent extracts (methanol, hexane, di ethyl ether). Among these nine Mentha species chocomint showed higher inhibition activity against all bacteria. Conclusions: It is concluded that monoterpenoids are mainly rich in Mentha plants. Moreover, most of extracts obtained from Mentha showed strong antimicrobial activity against bacteria. Of these, chocomint indicates the highest inhibition activity.