Antioxidant Activity,Antibacterial Activity And Mechanism Of Action Of The Essential Oil From Cyperus

With the continuous improvement of their living standards, consumers are paying more attention to food quality problems. Cyperus, as a kind of chinese herbal medicine with unique aroma, its main ingredient Cyperone has good antioxidant, antibacterial and some other biological characteristics, so it has been regarded as an excellent material to develop new natural food antioxidant and antiseptic. This research attached to Cyperus and make a further research of its antioxidant, antibacterial activity and antibacterial mechanism.The main research contents and resu Lts of this paper are as follows:(1)GC(GC- MS) technology were used for composition analysis of Cyperus essential oil, and 32 kinds of ingredients were identified, the main ingredients are: ?-cyperone(28.15%) ? ?-selinene(19.99%) ?Cyperene(17.73%)?oxo-?-ylangene(3.00%)?diisobutyl phthalate(2.48 %)??-bisabolene(2.14%)??-copaene(1.97%)?8,9-dehydron eoisolongifo lene(1.48%)??-gurjunene(1.29%)?longipinocarvone(1.11%).(2)In the paper, Cyperus essential oil was evaluated by employing various in vitro antioxidant assays such as free radical scavenging activity(ABTS?DPPH), ferric ion reducing antioxidant power, reducing power, protection of DNA and protein from oxidative damage. The resu Lts showed that, Cyperus essential oil has a good antioxidant capacity.(3)Based on the investigation of antibacterial activity of Cyperus essential oil,we found it had good inhibitory effect on six different food-borne pathogens tested, such as B. subtilis and S. aureus. Accor ding to the minimum inhibition concentration(MIC) and minimum bactericidal concentration(MBC) determination, Cyperus essential oil has good antibacterial effect on gram-positive bacteria but no impact on gram-negative bacteria. Through the growth curve investigation, we also found that Cyperus essential oil can effectively delay the arrival of the logarithmic phase of bacterial growth.(4)Finally, the antibacterial mechanism of Cyperus essential oil on Staphylococcus aureus and Bacillus subtilis was studied. We hypothesize that the essential oil may first destroy cell wall and membranes, next causing the losses of vital intracellu Lar materials, which finally resu Lt in the bacterial death based on the resu Lt of alkaline phosphatase(AKP), cell constituents' release assays, and ultrastructure analysis. Through the agarose gel retardation assays of DNA and sodium dodecyl su Lphate polyacrylamide gelelectrophoresis(SDS-PAGE) of whole cell protein, we found that Cyperus essential oil cou Ld prevent the normal synthesis of DNA and proteins that are required for bacterial growth,leading to inhibit the growth of bacteria and even death. To further explore its antibacterial mechanism, we used flow cytometry to analyze the living and necrotic rate of bacterial cells treated with Cyperus essential oil and detect cell apoptosis index changes by Annexin V-FITC/PI double staning method. Results showed that essential oil could inhibit the normal growth of bacteria and induce cell apoptosis quickly, and then kill bacteria. All the results indicated that the mechanism of action of Cyperus essential oil inhibit the growth of bacteria happens both on a cellular level and molecular level.