Antimicrobial activity and constituents of the leaf essential oil of Syzygium petelotii Merr. & Perry and Syzygium syzygioides (Miq.) Merr. & Perry from Vietnam.

Syzygium plants are known as sources of biologically active substances. The essential oils constituents and antimicrobial activity of Syzygium petelotii Merr. & Perry and Syzygium syzygioides (Miq.) Merr. & Perry from Vietnam are being reported. Essential oils were obtained by hydrodistillation of the leaves of S. petelotii and S. syzygioides collected from Pù Hoạt Nature Reserve, Vietnam. The constituents of the essential oils were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated by microdilution broth susceptibility assay. The results indicate that γ-guaiene (24.1%), β-caryphyllene (9.3%), α-pinene (7.8%), and β-pinene (6.1%) were the major compounds of S. petelotii. The main constituents of S. syzygioides were caryophyllene oxide (14.8%), α-pinene (10.6%), β-pinene (6.6%) and spathulenol (6.4%). The essential oil of S. petelotii showed pronounced antimicrobial activity against Pseudomonas aeruginosa ATCC27853 and Enterococcus faecalis ATCC299212, with minimum inhibitory concentration (MIC) values of 16.0 μg/mL and 64.0 μg/mL, respectively. The essential oil of S. syzygioides only displayed activity towards Pseudomonas aeruginosa ATCC27853 with MIC value of 32.0 μg/mL. Both essential oils exhibited antimicrobial activity towards Bacillus cereus ATCC14579 (MIC value, 128.0 μg/mL), and anti-candidal action against Candida albicans ATCC10231 with MIC value of 64.0 μg/mL. The chemical compositions and antimicrobial activity of essential oils of S. petelotii and S. syzygioides are being reported for the first time. [ABSTRACT FROM AUTHOR]