Essential oils of Zingiber officinale: Chemical composition, in vivo alleviation effects on TPA induced ear swelling in mice and in vitro bioactivities

Abstract

Zingiber officinale (ZO) is a traditional food condiment. The essential oils of Z. officinale (ZOEOs) are known to have multiple bioactivities. In this study, gas chromatography mass spectrometer (GC-MS) analytical method was used to identify active ingredient present in ZOEOs. A total of 41 compounds were identified in ZOEOs. Major components in ZOEOs were zingiberene (19.71%), (+)-β-cedrene (12.85%), farnesene (12.17%), α-curcumene (10.18%) and β-elemene (3.54%). Experimental results of 12-O-tetradecanoylphorbol-13 acetate (TPA) induced ear swelling validation mice model showed that ZOEOs treatment has better anti-inflammatory effect compared with ibuprofen (positive control) at high concentrations. Histological and immunohistochemical analysis showed that ZOEOs significantly decreased COX-2, IL-6 and NF-κB expression in a dose dependent manner. The mRNA levels of COX-2 and NF-κB were also down regulated by the application of ZOEOs. This indicated that ZOEOs exhibited positive effects in ear skin protection. Antibacterial experimental results showed that EOZOs had anti-bacterial effects on Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. DPPH radical scavenging, A549 cell line and LNCaP cell line inhibition results indicated that ZOEOs exhibited potential antioxidant and anti-tumor properties. The findings of these study provide scientific basis on therapeutic use of ZO in food, cosmetic and pharmaceutical industries.

Keywords: Zingiber officinale; anti-bacterial effects; anti-inflammation; anti-tumor property; antioxidation; edible spices; essential oil.

Figure 1

Inhibitory rate of mice ear weight in different groups. **ZOEOs vs. Model, P ≤ 0.01.

Figure 2

Histological sections of mice ear tissues in different mice groups (A) and the ear thickness (B). ^##Control vs. Model, P ≤ 0.01; **ZOEOs vs. Model, P ≤ 0.01.

Figure 3

Immunohistochemical staining of mice ears of COX-2, TNF-α, IL-6 and NF-κB (P65) and the determination of levels for COX-2 (A), TNF-α (B), IL-6 (C) and NF-κB (P65) (D). ^##Control vs. Model, P ≤ 0.01; **ZOEOs vs. Model, P ≤ 0.01.

Figure 4

Effects of ZOEOs on mRNA level [(A): COX-2, (B): NF- NF-κB (P65)] of inflammatory factors of mice ear tissues for different groups. ^##Control vs. Model, P ≤ 0.01; **ZOEOs vs. Model, P ≤ 0.01; *ZOEOs vs. Model, P ≤ 0.05.

Figure 5

SEM micrograph of before and after treatment with ZOEOs in E. coli (A), P. aeruginosa (B), S. aureus (C) at scale bar of 3 mm. Under 18,000 × magnification, untreated bacterial cells remained intact and evenly distributed with no sign of morphological depression, whereas bacterial cells treated with ZOEOs depicted morphological disruption with blisters and deep craters on their surface.

Figure 6

DPPH radical scavenging capacity of ZOEOs.

Figure 7

Anti-tumor properties (human lung cancer A549 and human prostate cell lines LNCaP) of ZOEOs.