Research On The Characterization And Antibacterial Activity Of Ginger Essential Oil/Palygorskite Composite (GEO-PGS)

In this paper,the supercritical CO₂ extraction technology of ginger essential oil?GEO?was studied by single-factor test and the response surface methodology?RSM?,and the optimum technological conditions were obtained.Then the modified Palygorskite?PGS?was used as the carrier of ginger essential oil,a new type of composite GEO-PGS was prepared.Characterization and properties of the composite GEO-PGS was studied.Finally,inhibition of GEO-PGS on Escherichia coli was confirmed by antibacterial test in vivo and in vitro,and the mechanism of antibacterial and anti-inflammatory action was studied at the molecular level.The main research contents and results are as follows:?1?The extraction of ginger essential oil.The extraction of ginger essential oil used supercritical CO₂ extraction technology,and the optimal extraction conditions were obtained by single factor test and response surface methodology?RSM?.The 6-gingerol yield as the investigation index of extraction.The optimal conditions for the extraction of ginger essential oil: carbon dioxide flow was 25L/h,ginger powder sieving mesh number was 80,adding entrainer of ethanol 92.46 mL,optimal 6-gingerol yield of 3.21%.?2?Characterization of GEO-PGS.The features of GEO-PGS were characterized by Fourier transform infrared spectroscopy?FTIR?,X ray diffraction?XRD?,thermal analyzer?TG-DSC?,Zeta potential analyzer,surface area and pore size analyzer?BET?and transmission electron microscopy?TEM?analysis.FTIR results showed that GEO has been successfully loaded with PGS.The results of XRD and BET showed that the GEO was only attached to the PGS surface in a physical way.TG-DSC analysis further confirmed the combination of GEO and PGS,and estimated that the content of GEO was 13.97%.The absolute value of Zeta potential of the complex was significantly lower than that of the single PGS.And TEM observation results showed that GEO had entered into the micro channel of PGS,which was successfully combined with it.?3?Study on the antibacterial activity of GEO-PGS in vitro.The minimum inhibitory concentration?MIC?of the GEO-PGS to Escherichia coli was 25mg·mL^-1,composite had better antibacterial activity compared with that of single GEO.The GEO-PGS has a strong inhibitory effect on the moratorium and the logarithm phase of growth of Escherichia coli.Gram staining experiments and adsorption experimentsshowed that the specific-targeting antibacterial capability of GEO-PGS,so it testified GEO-PGS combined the effective antibacterial ability of GEO and the stable adsorption of PGS.And in the same time,PGS as the carrier of GEO,the stability of compound obviously strengthened.Its heat resistance and weather resistance were significantly improved.?4?Study on the antibacterial activity of GEO-PGS in vivo.The experiment successfully established the model of Kunming mice infected with Escherichia coli.The body weight,amount of water intake and food intake,diarrhea rate,clinical symptom score and histopathology of intestinal tissue were measured.After the diarrhea mice were fed GEO-PGS,the body weight,food intake and water intake were significantly recovered;diarrhea and other clinical symptoms were significantly alleviated;impaired intestinal tissue was significantly improved.All these proved that GEO-PGS can treat bacterial infections of intestinum tissues.Compared with pure GEO and PGS,the effect of GEO-PGS was better.?5?Study on the molecular mechanism of the GEO-PGS on the inhibition of Escherichia coli.To analyze the gene expression of inflammatory cytokines in intestinum tissues after the infection of Escherichia coli and the intervention of GEO-PGS.The expression of inflammatory factors,such as Toll-like receptor 2?TLR-2?,interleukin 8?IL-8?,interleukin 6?IL-6?and tumor necrosis factor-??TNF-??has a significant increase.But the expression of inflammatory factors was significantly decreased after the intervention of GEO-PGS,it is suggested that the complex may inhibit the expression of inflammatory factors?TLR-2,IL-6,IL-8,TNF-??and treated the intestinal inflammation caused by Escherichia coli infection.In summary,the extraction technology of ginger essential oil was further optimized;GEO-PGS was prepared in our laboratory as a novel natural antibacterial agent;And the properties of GEO-PGS were characterized by a series of characterization studies.In vitro and in vivo antibacterial experiments showed that the GEO-PGS has a significant antibacterial effect on Escherichia coli,which also can treat the intestinal inflammation and intestinal dysfunction caused by Escherichia coli infection.