Chemical Composition of Essential Oils from the Leaves of Syzygium Bullockii and Syzygium Tsoongii in Ke Go Nature Reserve, Ha Tinh Province

Chemical composition of essential oils obtained from the leaf of Syzygium bullockii and Syzygium tsoongii were reported, corresponding oil content 0,36% and 0,27%. The analysis was performed by means of gas chromatography-flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). Twenty-seven components were identified in leaf oil of Syzygium bullockii, which represented about 76,75% of the total composition of the oil and six components were not identified, which represented 15,72%. The major constituents of the essential oil were (E)-caryophyllene (49,65%), spathulenol (4,29%), caryophyllene oxide (4,14%), bicyclogermacrene (3,35%), 2-tridecanone (3,25%). Fourty-six components were identified in leaf oil of Syzygium tsoongii, which presented about 99.71% of the total composition of the oil. The major constituents of the essential oil were E-caryophyllene (23,40%), bicyclogermacrene (21,23%), (Z)-β-ocimene (10,61%), α-humulene (6,33%), (E)-β-ocimene (4,99%). For the first time, the chemical compositions of the essential oils of Syzygium bullockii and Syzygium tsoongii from Vietnam were being reported.