Phytochemical Analysis of the Essential Oils From the Rhizomes of Three Vietnamese Curcuma Species and Their Antimicrobial Activity

Objective/Background The essential oils (EOs) of Curcuma species contain various volatile compounds with bioactivity. However, the phytochemical profile of Curcuma thorelii and the antimicrobial activities of Curcuma rhabdota, and Curcuma petiolata have received limited attention. This study aims to characterize and compare the major compounds and the antimicrobial activities of EOs extracted from the rhizomes of C. rhabdota, C. thorelii, and C. petiolata collected in Vietnam . Methods EOs were obtained by hydrodistillation of the rhizomes of three Curcuma species. The chemical profiles were determined using gas chromatography-mass spectrometry (GC-MS). The antimicrobial activities against bacteria and a pathogenic fungus were determined through the broth dilution method. Results The volatile profiles of C. rhabdota, C. thorelii, and C. petiolata EOs included 63 (97.1%), 47 (98.0%), and 50 (95.6%) compounds, respectively. The major compound in the EO of C. rhabdota rhizomes was 3-carene (16.6%), followed by camphene (9.8%), α-copaene (7.4%), γ-terpinene (7.3%), camphor (5.9%), and β-curcumene (5.7%). The predominant compounds of the EO extracted from C. thorelii rhizome were xanthorrhizol (40.7%), β-curcumene (20.7%), and α-curcumene (8.9%), while camphene (17.0%), ( E)- β-elemenone (16.8%), (E)-β-farnesene (13.6%), germacrone (8.9%), 1,8-cineole (7.2%), and camphor (6.0%) were the most abundant components in C. petiolata rhizomes. Except for Pseudomonas aeruginosa, which was less susceptible to the EOs with a minimum inhibitory concentration (MIC) value of 128 μg/mL, the three oil samples exhibited potent antimicrobial activities against all investigated strains with MIC values in the range of 2-32 μg/mL. Especially, the EO of C. thorelii rhizomes showed intense activity against Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Candida albicans with a MIC value of 2 µg/mL. Conclusion The results showed the chemical variability of EOs from three Curcuma species and the prepared EO samples showed potent antimicrobial activities against several microbial strains, indicating a high potential application as a food preservative and in the pharmaceutical industry.