| Aconitum szechenyianum Gay. is dry earthnut of Ranunculaceae Plants Aconitum pendulum Busch., and it is mainly produced in Shannxi Taibai, growing in the mountainous grasscluster or forest edge of the elevation more than 2500 meters. Aconitum pendulum Busch. is mainly distributed in some regions of China, such as Xizang, Ningxia, Gansu, Shaanxi etc provinces . As a traditional Chinese medicinal herb, it exhibits blood-activated, detumescent and styptic effects, and treats joint pain, arthritic and rheumatic diseases etc. Pharmacological studies demonstrated that its injection possesses anti-inflammatory, analgesic and antitumor activities. There were a few reports on the constituents of Aconitum szechenyianum Gay., but to the best of our knowledge, no detailed report has yet appeared on the fatty acid components of it up to now.There are two parts in this thesis:Part one: Review1. Study survey of Aconitum szechenyianum Gay.It includes summary, resource distribution and authentication, study progress on chemical composition, pharmacological effects about Aconitum szechenyianum Gay.2. Study survey of microwave-assisted extractionIt includes the definition and characteristics of microwave, the theory and characteristics of microwave heating and microwave-assisted extraction, the extraction apparatus, experiment condition and the application.3. Study survey of fatty acidsIt mainly involves extraction, derivatization to methyl esters, analysis and pharmacological research of fatty acids.Part two: Research papersFour main contents are included in this part.1. Microwave-assisted extraction (MAE) of fatty acids from Aconitum szechenyianum Gay. The extraction solvent, solvent concentration, microwave power, radiation time, and ratio of solid to liquid were valued to compare the extraction yield of fatty acids. The optimum process condition was confirmed that microwave power was 400 W, acetone-water solvent concentration 90%, ratio of solid to liquid 1 g:16 mL, radiation time 5 min, and an extraction yield of 13.0% of total fatty acids could be obtained.2. Soxhiet extraction (SE) of fatty acids from Aconitum szechenyianum Gay.About 10.0 g powder was weighed, quantitatively transferred into a filter paper extraction thimble and inserted into a 250 mL reflux flask, then extracted with 160 mL 90% acetone-water solvent for about 6 h in a soxhiet apparatus.3. Analysis of fatty acids in extracts of Aconitum szechenyianum Gay. with GC-MSThe analysis condition was optimized at the aspects of injection temperature, split mode, split ratio, injection volume, flow of carrier gas, temperature programmed and so on. The proper conditions are as follows: A fused silica capillary Rtx?-5MS%dipheny-95% dimethylpolysiloxane column (30 m×0.25 mm i.d., film thickness 0.25μm) was used for the separation. Helium at a constant flow-rate of 1.00 mL/min was used as the carrier gas. 1μL extract was injected into the column with a split ratio set at 10:1 and injector port temperature at 260℃. The GC program was initiated by a column temperature set at 184℃, and then increased to 191℃at a rate of 0.2℃/min. Temperatures of the ion source and interface were all 200℃. The mass spectrometer was operated with El-mode at 70eV and the mass range was from m/z 40 to 500 amu.The extracts of Aconitum szechenyianum Gay. obtained by microwave-assisted extraction and soxhiet extraction were identified respectively under the optimum GC-MS analysis condition. And relative amount of individual components were calculated based on GC peak areas.4. Comparision of microwave-assisted extraction and soxhiet extractionIt can be seen that 8, 9 kinds of fatty acids in the MAE and SE extracts have been identified respectively. The chemical compositions of both extracts are similar, yet relative amount of the same fatty acids have few difference. The main components are palmitoleic acid, palmitic acid, linoleic acid, linolenic acid, oleic acid and stearic acids. Compared with soxhiet extraction, much shorter extraction time, better yield, lower cost and better environment ecology is advantageous for the proposed microwave-assisted extraction method. |
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