The Studies On The Chemical Constituents And Bioactivities Of Nicotiana Tobacum L.

In this study,the aromatic chemical compounds of flue-cured K326 were analyzed by varieties extractions and GC-MS. The best extraction method of tobacco is screened out and optimized. The fragments of flue-cured concrete was separated and analyzed by chromatography. glycosidic compounds were isolated from the ethyl acetate fraction. And then the research that using the Maillard reaction synthesizes and modifies the chemical composition of tobacco and flavored in sigarette was studied. The vitro antioxidant activity of fragmentes, polyohenols,alkaloid,glycoside of flue-curd was evaluated.Results were summarized as follows:1. The chemical constituents of flue-cured were extracted by hydrodistillation,simultaneous distillation extraction,old soak, ultrasonic extraction, heat reflux extraction, Soxhlet extraction method.The extract was analyzed by GC-MS.The results based on the extraction efficiency and chemical composition showed that the ethanol extract of Soxhlet extraction method contains more comprehensive aroma components.And it is the most highest extraction efficiency method of extracting the aroma compounds. Therefore, Soxhlet extraction method choosing ethanol as a solvent is the best method for extractingchemical composition of tobacco.2. Two kinds of Soxhlet extraction of the neutral flavor constituents from tobacco were optimized by single factor( extraction time, temperature, ratio of material to liquid)and BBD central combination of response surface method. The establishment of two quadratic response surface regression model to predict the extraction rate.The optimal parameters of the classic Soxhlet extraction method were determined as follow:a time of 7.41 h, a temperature of 130.24 ℃,a liquid-solid ratio of 1: 27.22. A verification experiment was performed under the conditions, and the avarage yield was 55.16 %.The theoretical value is 54.99 %,with a difference of 0.17 %.The optimal parameters of the auto-Soxhlet extraction method were determined as follow:boiling and leaching time of 42.44 and 84.88 min, a temperature of 135.95 ℃,a liquid-solid ratio of 1: 18.03. A verification experiment was performed under the conditions, and the avarage yield was 44.9 %.The theoretical value is 45.17 %,with a difference of 0.27 %.3.Separate and analyzed the chemical constituents of tobacco debris by extraction, chromatography and GC-MS. According to the analysis results, the ethyl acetate layer contains a large number of chemical constituents. Ten compounds were isolated and purified and identified the structurewith NMR, IR and other means.They are scopoletin(1), quercetin(2),rutin(3).4. The modification of chemical composition of the flue-cured was studied by Maillard reaction. The chemical composition of the reaction products were analyzed by GC-MS and sensory flavor smoking. According to the analysis results, the sucrose/leucine,mannose/phenylalanine, rhamnose/ph- enylalanine Maillard reaction products can significantly increase the chemical composition and the flavor of cigarette smoking.5.The vitro antioxidant activity of fragmentes,polyohenols,alkaloid,glycoside of flue-curd was evaluated by DPPH-method and scavenging capacity to hydroxyl free radical method. Now the results were detecting.