| Since Lavandula angustifolia was successfully introduced in Yili region ofXinjiang in1960s, more and more aromatic plants were commercially planted thereand developed rapidly, which become a characteristic key industries of the region.The various products, owning unique fragrant odors and effectiveness, derived fromaromatic plants are gaining widespread popularity. Among them, commercial essentialoils, as special cosmetic and effective products, are sold on the market of home andabroad, which attracted more and more consumers and enjoyed great potential andpromising prospects. So far, GC-MS technique become a routine and necessity infundamental componential analysis of volatile complex samples like essential oils.However, the polarity distribution of different kinds of essential oils was not thesame, thus selection of GC, GC-MS columns was a key for successful separation.Essential oil production in Xinjiang is large, but the price is much lower than theimported, which is due to the absence of relevant standard for their industrialproduction and unsuitablity of ISO standards for Xinjiang local essential oils, so it isurgent to establish local standard. In addition, researches on physiological activities ofessential oil were mainly done immediately after extraction, but commercial essentialoils were stored for a period of time, thus the ingredients and relevant activities maybe changed. Nevertheless, studies on activities of commercial essential oils were few.Therefore, take these problems into consideration, there is a great necessity to geta detailed understanding of the chemical composition and biological activities for thecommercial essential oils. Four columns with different polarities were chosen forseparation of three representative Xinjiang locally commercial essential oils, their invitro antioxidant activities were also comparatively investigated, which could lay thefoundation for their exploration and utilization of aromatic plant essential oils.Detailed research contents and methods in the thesis were as follows: (1) Based on gas chromatography-mass spectrometry (GC-MS) technique, thechemical compositions of Xinjiang locally commercial Lavandula angustifolia,Mentha piperita L. and Rosmarinus officinalis L. oils, were analyzed based on fourcapillary columns of different polarities (Rxi-5Sil MS column with low polarity,GsBP-35MS column with polarity close to medium, Rxi-17Sil-ms column withmedium polarity, GsBP-Inowax-MS column with high polairty). Many multi-steptemperature programs were investigated to ensure the best GC-MS chromatographicseparation conditions for each oil. Mass spectra (MS) and retention indices (RI) wereused to identify the compounds. Separation performances of essential oils on fourcolumns were deeply evaluated and the effect of column polarity on oil separationwas researched, so as to determine the best analysis column type for each oil.(2) Under the optimized GC-MS conditions, seven brands of Lavandulaangustifolia oil, three brands of Mentha piperita L. oil and two brands of Rosmarinusofficinalis L. oil were studied for componential analysis to screen the characteristiccomponents, the content ranges were also limited, which offered credible data for theestablishment of local standards of Xinjiang commercial essential oil products.(3)1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, and-carotenebleaching method was employed to evaluate the in vitro antioxidant activities of thestudied commercial essential oils from different sources and brands. In the DPPHradical scavenging and-carotene bleaching experiment, it was showed that thestudied essential oils had a certain antioxidant activities, but all the tested commercialessential oils exhibited much lower content level compared with literatures andpositive control butylated hydroxytoluene (BHT), which may due to the large scaleextraction process and longer placed time after extraction. |
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