Volatile Constituents and In vitro Antimicrobial Activities of Essential Oils from Leaves of Siliquamomum oreodoxa N.S. Lý & Škorničk and Curcuma thorelii Gagnep. (Zingiberaceae) Growing in Vietnam

Siliquamomum oreodoxa and Curcuma thorelii in the family Zingiberaceae are two new species native to Vietnam. In the present work, volatile composition of essential oils (EOs) from leaves of the two plant species and their antimicrobial activities were reported for the first time. The gas chromatography-mass spectrometry analytical results revealed that the major constituents of the S. oreodoxa leaf EO were α-pinene (39.23%), β-pinene (26.34%), myrtenyl acetate (8.24%), and limonene (7.85%). The results also showed the C. thorelii EO was predominantly composed of β-pinene (21.58%) and caryophyllene (14.26%). In the antimicrobial assay, the two EOs were found to possess strong antimicrobial activities against multiple pathogenic bacterial and fungal strains, with minimum inhibitory concentrations ranging between 32 and 128 μg/mL.