Chemical composition and anti-Helicobacter pylori activity of essential oils from rhizomes and tuberous roots of Boesenbergia rotunda (L.) Mansf.

Boesenbergia rotunda (Zingiberaceae) is a well-known traditional medicinal and culinary plant found in Southeast Asia and China. The extracts of this plant have been shown to have antibacterial potential against several pathogenic bacteria, including Helicobacter pylori. However, the antibacterial activity of the essential oils (EOs) from B. rotunda toward H. pylori has not been reported. Hence, the present study investigated the chemical compositions and antibacterial properties of the EOs extracted from the rhizomes and tuberous roots of B. rotunda against H. pylori. GC–MS analysis revealed that the rhizome EO was rich in camphor (28.6 %), 1,8-cineole (16.0 %), geraniol (15.5 %) and E-β-ocimene (12.8 %), while the tuberous root EO predominantly contained E-β-ocimene (31.9 %), camphor (19.9 %), geraniol (16.3 %), limonene (7.5 %) and 1,8-cineole (4.3 %). Both of the EOs exhibited strong anti-H. pylori activity, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.31 and 2.50 mg/mL for the rhizome EO and 0.16 and 1.25 mg/mL for the tuberous root EO, respectively. In vitro urease inhibition assay revealed that these EOs exhibited comparable and significant inhibitory action on the urease activity of H. pylori. Mechanism of action showed that the tuberous root EO had a stronger antibiofilm effect than the rhizome EO and both of the EOs demonstrated potent membrane-permeabilising properties resulting in the leakage of intracellular proteins from H. pylori cells. These findings support the potential application of B. rotunda EOs as effective natural agents for the prevention and control of H. pylori infections.