Essential oils of Lauraceae: antimicrobial activity and constituents of essential oil from two Machilus species from Vietnam

The chemical constituents and antimicrobial activity of the essential oils isolated from the leaves of Machilus cicatricosa S.K. Lee and Machilus bonii Lecomte from Vietnam were studied and reported. The techniques of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS) were used to characterize the chemical constituents of the essential oil while the microdilution assay was used to evaluate the antimicrobial activity. The main constituents of the leaf oil of M. cicatricosa were alpha-pinene (20.6%), bicyclogermacrene (15.2%), linalool (14.9%), and beta-pinene (8.4%). On the other hand (E)-beta-ocimene (26.3%), bicyclogermacrene (23.6%) and (E)-nerolidol (9.1%) were the major constituents of M. bonii leaf essential oil. The studied essential oils displayed antimicrobial activity against Enterococcus faecalis ATCC 29212, and Staphylococcus aureus ATCC 25923, with minimum inhibitory concentration (MIC) value of 64.0 mu g/mL. In addition, essential oil from the leaf of M. bonii was the most active towards Bacillus cereus ATCC14579 with MIC value of 64.0 mu g/mL, while M. cicatricosa showed stronger anti-candidal activity against Candida albicans ATCC 10231 with MIC value of 32.0 mu g/mL. This is the first report on the chemical constituents and antimicrobial activity of the essential oils of M. cicatricosa and M. bonii.