Chemical profiles of essential oil from Javanese turmeric (Curcuma xanthorrhiza Roxb.), evaluation of its antibacterial and antibiofilm activities against selected clinical isolates

Antibacterial resistance has become a major global public health issue. Pathogens such as Staphylococcus aureus, Bacillus subtillis, Escherichia coli, and Klebsiella pneumoniae associated with most community infections are linked with antibiotic resistance. Curcuma xanthorrhiza is a traditional medicine used to prevent and cure bacterial infection. This study evaluated the antibacterial and antibiofilm activities of C. xanthorrhiza essential oil (EO) against selected clinical isolates, as well as their interaction with conventional antibiotics. Chromatographic analysis revealed that the principal constituents of C. xanthorrhiza EO are α-curcumene and β-curcumene, representing 22.11 and 23.39% of the oil content, respectively. Curzerene, camphor, and xanthorrhizol also made up a significant fraction of the essential oils extract, accounting for more than 4.5%. C. xanthorrizha EO had considerable antibacterial activity against Bacillus subtillis with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 7.8 and 15.6 µg/mL, but exhibited moderate activity against Staphylococcus aureus with MIC value of 31.2 µg/mL. Moreover, when used in combination, C. xanthorrhiza EO increased the antibacterial activity of ampicillin, resulting in a synergistic effect. C. xanthorrhiza EO inhibited the formation of biofilm in B. subtillis and S. aureus. C. xanthorrhiza EO significantly reduced the viability of established biofilm in B. subtillis and S. aureus at 15.6 µg/mL (2 MIC) and 125 µg/mL (4 MIC). The results showed that C. xanthorrhiza EO had potent antibacterial activity, inhibiting biofilm and increasing the effect of ampicillin against clinical isolate pathogen particularly B. subtillis.