Chemical component and antibacterial activity of ginger (Zingiber officinale Roscoe) essential oil

Abstract:

[Background] With the increase of resistant microorganisms and the enhancement of drug resistance, it has become a global concern to find new drugs against resistant microorganisms. Ginger essential oil is a pure natural plant essential oil, which is a preferred choice of natural antibacterial materials. [Objective] To analyze chemical components of ginger essential oil, study its antibacterial activity against common opportunistic pathogens, and illustrate its possible antibacterial mechanisms. [Methods] The chemical components of ginger essential oil were analyzed using gas chromatography/ mass spectrometry (GC/MS). The antibacterial activity of ginger essential oil was studied by Oxford cup method, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC), respectively. Its kinetic growth characteristics were recorded by dynamic growth curves. The effect of ginger essential oil on bacterial ultrastructure was observed by transmission electron microscopy (TEM). [Results] The main chemical components of ginger essential oil were terpenes, including zingiberene (22.014%), β-sesquiphellandrene (11.276%), α-farnesene (8.222%), α-curcumene (6.854%), zingerone (5.610%), gingerdione (5.192%), 6-shogaol (4.670%), sabinene (3.393%), and β-bisabolene (3.080%). The MIC and MBC of ginger essential oil were 2.3 μg/mL and 4.6 μg/mL for Bacillus subtilis, 9.2 μg/mL and 18.4 μg/mL for both Staphylococcus epidermis and Staphylococcus aureus, 18.4 μg/mL and 36.8 μg/mL for Klebsiella pneumoniae, respectively. The experimental results of dynamic growth curves showed that ginger essential oil could prolong the growth lag phase and inhibit the growth rate of the bacteria. Moreover, results of TEM observation showed that ginger essential oil could destroy the cellular membrane and cause the leakage of the intracellular macromolecules. [Conclusion] Ginger essential oil is rich in terpenoids and has moderate antibacterial activity, which could destroy the integrity of cellular membrane and cause cell damage and death. This paper is expected to provide new methods for the prevention and control of harmful microorganisms.

Key words:ginger essential oil, chemical component, antibacterial activity