Studies On Extracting Process, Chemical Constituents And Antibacterial Effects Of Essential Oils From Allium Mongolicum Regel

This study was conducted to investigate the extraction process, chemical composition of essential oils from Allium Mongolicum Regel and its bacteriostatic action toward Escherichia.coli, Staphylococcus.aureus and Salmonella as well as the effects on the growth of Lactic acid Bacteria. The main contents and conclusions are as follows:(1)Based on the results of the single factor analysis method, orthogonal expriment was carried out in this study on the index containing the yield of essential oils and the factors containing the soaking time (A), the ratio of material to liquid (B), the ultrasonic treatment time (C) and the distillation time (D) through vapor distillation from Allium Mongolicum Regel powder to determine the optimum extraction parameters of essential oils. The results showed that the impact degree of different expriment factors was the ultrasonic treatment time > the ratio of material to liquid=the distillation time > the soaking time. The best combination was A1B3C3D3 , that was to say, when solid to liquid ratio at 1:11, soaking for 1.5h, ultrasonic treatment for 20min and distillation for 3.5h, a maximum extraction yield of 0.46% for essential oils was obtained under above conditions.(2)The chemical compositions of essensial oils were analysed and identified by gas chromatography-mass spectrometry. A total of 60 chromatographicpeaks were chosen and NIST Ms Search 2.0 database was applied to identify 37 compounds, and most of them were sulfur compounds in which the contents of three dimethyl sulfide, diallyl disulphide, (Trisulfide, methyl 2-propenyl),(Tetrasulfide, dimethyl), (Trisulfide,di-2-propenyl), (Disulfide,methyl,2-propenyl), (Tetrasulfide, di-2-propenyl) were 12.71%,2.53%,28.84%,10.53%,12.21%,9.44% and 2.66% respectively. The total content reached 78.92% of overall composition contents.(3)Bacteriostatic action of essential oils from Allium Mongolicum Regel was determined through bacteriostatic test in vitro and the minimum inhibitory concentration (MIC) and the minimal bacteriocidal concentration (MBC) were determined with serial dilution method. The results indicated that the essential oils from Allium Mongolicum Regel strong exhibited strong inhibitory effects on Escherichia.coli, Staphylococcus.aureus and Salmonella, and the higher concentration, the better inhibition.The minimum inhibitory concentration (MIC) were 0.625%, 1.25% and 0.312% respectively; the minimum bactericidal concentration (MBC) were 2.50%, 2.50% and 0.625% respectively.(4)The effects of different concentrations of essential oils on the growth of Lactic acid Bacteria were researched with plate count method. There were no significant differences in the number of Lactic acid Bacteria compared with the control group when the concentration of essential oils ranged from 5% to 15% , which testify no notable influences on the growth of Lactic acid Bacteria within such areas. When the concentration of essential oils reached up to 20%, indicating a downward trend in the number of growing Lactic acid Bacteria.