Chemical profiling and antimicrobial activity of essential oil from Curcuma aeruginosa Roxb.,Curcuma glans K.Larsen&J.Mood and Curcuma cf.xanthorrhiza Roxb.collected in Thailand

ABSTRACT

Objective: To investigate chemical constituents and new antimicrobial agents among essential oils from the rhizomes of Curcuma aeruginosa(C.aeruginosa)Roxb.,Curcuma glans K.Larsen&J.Mood and Curcuma cf.xanthorrhiza Roxb. Methods: The essential oils were obtained by hydro-distillation and analyzed by gas chromatography/mass spectroscopy.Agar-well diffusion assay was used to study the anti-microbial activity and also broth-micro dilution techniques were examined for minimum inhibitory concentration (MIC)against four bacterial strains and yeast. Results: The gas chromatography/mass spectroscopy analysis showed monoterpenes predominantly(88.53%)in the rhizome oil of Curcuma cf.xanthorrhiza.Sesquiterpenes (50.10%) was the most abundant component in the essential oil of C. glans, while monoterpenes(45.55%)and sesquiterpenes(45.81%)were found in C.aeruginosa with a significant amount. The major components of C. aeruginosa were characterized as camphor (29.39%) and germacrone (21.21%). Germacrone (15.76%),β-pinene (9.97%) and camphor (9.96%) were found as major compounds in the rhizome oils of C. glans while α-terpinolene (24.86%) and p-cymen-7-ol(12.17%) were found as major compo-sitions in Curcuma cf.xanthorrhiza.The essential oils were tested against four bacterial strains and yeast.As a result,the rhizome oil of C.aeruginosa exhibited potent activity against Staphylococcus aureus [inhibition zone (21.94 ± 0.24) mm, MIC 125 μg/mL], Bacillus cereus [inhibition zone (20.83 ± 0.36) mm, MIC 125 μg/mL], and Candida albicans[inhibition zone(11.60 ± 0.30)mm,MIC 250 μg/mL]. Conclusions: The essential oils from three Curcuma species possessed greater activity against the gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) than gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The results suggest that the essential oils from the fresh rhizome of Curcuma spp. might be a po-tential source of natural antimicrobial substances.