Chemical constituents and biological activities of the seed essential oil from Michelia tonkinensis grown in Thanh Hoa province, Viet Nam

Essential oils (EOs) from the seed of Michelia tonkinensis were extracted in four ways hydrodistillation (HD), microwave-assisted hydrodistillation (MHD), ultrasound-assisted hydrodistillation (UHD) and enzyme-assisted hydrodistillation (EHD). The chemical constituents of these EOs were analysed by gas chromatography (GC-FID) and gas chromatography/mass spectrometry (GC/MS). Phenylpropanoids were the main components in which safrole is the dominant constituent (82.98-91.53 %), followed by monoterpene hydrocarbons (5.26-11.94 %). In comparison with traditional hydrodistillation method (HD only), the EOs obtained from the MHD, UHD and EHD methods have the higher safrole contents (91.32 %, 90.96 % and 90.25 %, respectively). The essential oils were also tested for their antioxidant, anti-imflammatory, antimicrobial and cytotoxic activities. The HD essential oil sample showed inhibitory activity against 6/8 tested microorganisms, i.e., Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtillis, Candida albicans, and Saccharomyces cerevisiae. The MHD and EHD exhibited the inhibitory activity against three strains E. coli, A. niger and F. oxysporum. The UHD inhibited E. coli and F. oxysporum.