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Antibacterial activity and kinetics of Litsea cubeba oil on Escherichia coli.

Li WR, Shi QS, Liang Q, Xie XB, Huang XM, Chen YB - PLoS ONE (2014)

Bottom Line: Thus many holes and gaps were observed on the damaged cells, which led to their death eventually.The antibacterial effects of litsea cubeba oil mainly attributed to the presence of aldehydes, which accounted for approximately 70% in its whole components analyzed by GC/MS.Based on the antimicrobial properties, litsea cubeba oil would have a broad application in the antimicrobial industry.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China.

ABSTRACT
Litsea cubeba oil is extracted from the fresh fruits of Litsea cubeba by distillation. In this study, its chemical constituents, antibacterial activity, kinetics and effects against Escherichia coli were studied. Its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were both 0.125% (v/v) by toxic food method. Moreover, the antibacterial kinetic curves indicated 0.0625% (v/v) of litsea cubeba oil was able to prolong the growth lag phase of E. coli cells to approximate 12 hours while 0.125% (v/v) of litsea cubeba oil was able to kill the cells completely. Furthermore, transmission electron microscope (TEM) observation showed most E. coli cells treated with 0.125% (v/v) of litsea cubeba oil were killed or destroyed severely within 2 hours. The litsea cubeba oil might penetrate and destroy the outer and inner membrane of E. coli cells. Thus many holes and gaps were observed on the damaged cells, which led to their death eventually. The antibacterial effects of litsea cubeba oil mainly attributed to the presence of aldehydes, which accounted for approximately 70% in its whole components analyzed by GC/MS. Based on the antimicrobial properties, litsea cubeba oil would have a broad application in the antimicrobial industry.

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Related in: MedlinePlus

Photos for morphological alterations of E. coli cells observed by TEM.(A) to (B) Control; (C) 0.125% (v/v); (D) 0.25% (v/v).
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pone-0110983-g004: Photos for morphological alterations of E. coli cells observed by TEM.(A) to (B) Control; (C) 0.125% (v/v); (D) 0.25% (v/v).

Mentions: The electron micrographs of E. coli cells were displayed in Fig. 4. The bacterial cells in control (Fig. 4a, b) showed typical characters of rod-shaped bacteria. The cell surface was smooth and intact, and the peritrichous flagella were obvious and clear. The cells treated with 0.125% (Fig. 4c) and 0.25% (v/v) (Fig. 4d) of oil for 2 h were destroyed severely. The flagella were damaged and even disappeared. This undoubtedly impeded the cells movement and accelerated their death. Moreover, bright and dark area appeared on the cell images, indicating the structure density of the cells varied. The bright area showed the cellular membrane was damaged. The cells in 0.25% (v/v) experimental oil group were destroyed more severely than that in 0.125% (v/v) experimental oil group. Essential oils can penetrate the plasma membrane because of their lipophilic characters [27], [28]. So the litsea cubeba oil might penetrate and destroy both outer and inner membrane of E. coli cells. Thus many bright holes and gaps were observed on the damaged cells and this led to their death. Then cell lysis happened and many cells were fragmentary. Moreover, the results also indicated litsea cubeba oil had a rapid bactericidal effect. Only treated with the oil for 2 h, the cells were both damaged severely and most cells were killed obviously. According to our experiments (data was not shown), the antibacterial effect of litsea cubeba oil was good but not long-lasting and its lemon aroma is strong but not long-lasting too. Its antibacterial property may be due to its rapid volatilization characters.


Antibacterial activity and kinetics of Litsea cubeba oil on Escherichia coli.

Li WR, Shi QS, Liang Q, Xie XB, Huang XM, Chen YB - PLoS ONE (2014)

Photos for morphological alterations of E. coli cells observed by TEM.(A) to (B) Control; (C) 0.125% (v/v); (D) 0.25% (v/v).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4220960&req=5

pone-0110983-g004: Photos for morphological alterations of E. coli cells observed by TEM.(A) to (B) Control; (C) 0.125% (v/v); (D) 0.25% (v/v).
Mentions: The electron micrographs of E. coli cells were displayed in Fig. 4. The bacterial cells in control (Fig. 4a, b) showed typical characters of rod-shaped bacteria. The cell surface was smooth and intact, and the peritrichous flagella were obvious and clear. The cells treated with 0.125% (Fig. 4c) and 0.25% (v/v) (Fig. 4d) of oil for 2 h were destroyed severely. The flagella were damaged and even disappeared. This undoubtedly impeded the cells movement and accelerated their death. Moreover, bright and dark area appeared on the cell images, indicating the structure density of the cells varied. The bright area showed the cellular membrane was damaged. The cells in 0.25% (v/v) experimental oil group were destroyed more severely than that in 0.125% (v/v) experimental oil group. Essential oils can penetrate the plasma membrane because of their lipophilic characters [27], [28]. So the litsea cubeba oil might penetrate and destroy both outer and inner membrane of E. coli cells. Thus many bright holes and gaps were observed on the damaged cells and this led to their death. Then cell lysis happened and many cells were fragmentary. Moreover, the results also indicated litsea cubeba oil had a rapid bactericidal effect. Only treated with the oil for 2 h, the cells were both damaged severely and most cells were killed obviously. According to our experiments (data was not shown), the antibacterial effect of litsea cubeba oil was good but not long-lasting and its lemon aroma is strong but not long-lasting too. Its antibacterial property may be due to its rapid volatilization characters.

Bottom Line: Thus many holes and gaps were observed on the damaged cells, which led to their death eventually.The antibacterial effects of litsea cubeba oil mainly attributed to the presence of aldehydes, which accounted for approximately 70% in its whole components analyzed by GC/MS.Based on the antimicrobial properties, litsea cubeba oil would have a broad application in the antimicrobial industry.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China.

ABSTRACT
Litsea cubeba oil is extracted from the fresh fruits of Litsea cubeba by distillation. In this study, its chemical constituents, antibacterial activity, kinetics and effects against Escherichia coli were studied. Its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were both 0.125% (v/v) by toxic food method. Moreover, the antibacterial kinetic curves indicated 0.0625% (v/v) of litsea cubeba oil was able to prolong the growth lag phase of E. coli cells to approximate 12 hours while 0.125% (v/v) of litsea cubeba oil was able to kill the cells completely. Furthermore, transmission electron microscope (TEM) observation showed most E. coli cells treated with 0.125% (v/v) of litsea cubeba oil were killed or destroyed severely within 2 hours. The litsea cubeba oil might penetrate and destroy the outer and inner membrane of E. coli cells. Thus many holes and gaps were observed on the damaged cells, which led to their death eventually. The antibacterial effects of litsea cubeba oil mainly attributed to the presence of aldehydes, which accounted for approximately 70% in its whole components analyzed by GC/MS. Based on the antimicrobial properties, litsea cubeba oil would have a broad application in the antimicrobial industry.

Show MeSH
Related in: MedlinePlus