Study On Extraction Of Alkaloids From Aconitum Szechenyianum Gay. And Simultaneous Determination Of Three Aconitum Alkaloids In Several Herbal Medicines By HPLC

Aconitum szechenyianum Gay., which is acrid and bitter in taste andhot in nature, is the dry rhizome of ranunculaceae plant. It has been used as medicinein folk of northwest china because it performs well in vanishing ecchymosis,exspelling wind and removing dampness, relieving swelling and pain,anti-inflammatory, analgesic, and etc. But a little about the chemical constituents ofAconitum szechenyianum Gay. has been reported. In the current work, extractionprocesses were optimized by L₁₆(4⁵) orthogonal test and univariant methods in turn,and a simple HPLC-PDA method was developed for simultaneous quantitativedetermination of three diterpenoid alkaloids in several herbals most often used inChinese folk medicines.There are two parts in this thesis.Part one: Review1 Research advance about Aconitum plantsChemical components, pharmacological activities and toxicity are included in theresearch advance of Aconitum plants. Several kinds of chemical components had beenfound in aconite, including polysaccharides, protein, essential oil, amino acids, traceelements, alkaloids, and etc. Aconitum plants have marked pharmacological effects intreating rheumatic arthritis, rheumatoid arthritis, traumatic injuries, waist-leg pain,overload injury, chilblain, snakebite and anti-tumor etc, but it is very easy to poison ifyou do not use Aconitum plants properly because alkaloids in aconite have hightoxicity, especially for diterpene alkaloids.2 Research advance about alkaloidsAlkaloids are the mainly pharmacological active components in Aconitum plants.There are five parts in the research advance of alkaloids origin, general characters,extraction and separation methods, analytic methods, the development direction andsome advices. Part two: Research papersIn this part, two departments are involved: study on the optimum extractingconditions of total alkaloids and aconitine in A. szechenyianum Gay., and simultaneousdetermination of three Aconitum alkaloids in several herbal medicines by PDA-HPLC.Extraction processes were optimized by L₁₆(4⁵) orthogonal test and univariantmethods in turn. The contents of total alkaloids and aconitine obtained from A.szechenyianum Gay. were used as index to evaluate the extraction conditions. Theaconite root was pulverized into powder, and passed through a 0.45μm sieve.Approximately 10.0 g of powder was refluxed with an acidic alcohol solution. Theextraction process repeated 3 times. Then the extract was combined and filtered, andthe alcohol was evaporated under reduced pressure. The acidic aqueous solution wasbasified with concentrated ammonia solution to pH10.0 and further extracted withchloroform. The chloroform divided into two parts was evaporated in a vacuum todryness and the residual was used to determine total alkaloids and aconitine guided bybromophenol blue colorimetry and HPLC method, respectively. The results indicatedthat aconitine and total alkaloids had different extracting conditions. The operation ofthis method is simple. The result was accurate, and the reproducibity was good.Then the power of Aconitum carmichaeli Debx., Aconitum Kusnezoffii Reichb.,Aconitum taipeicum Hand-Mazz. and three kinds of Aconitum szechenyianum Gay.was extracted with the optimized condition for total alkaloids. Aconitine, mesaconitineand hypaconitine in these samples were determinated by HPLC, simultaneously. Threeregression equations showed good linear relationships (r＞0.999) in the concentrationrange of 1.0-200.0μg/mL. Parameters such as linearity, precision, repeatability,recovery, limit of quantitation (LOQ), limit of detection (LOD) and theoretical plateswere studied and the method was satisfactory. The quantitation results indicated thatcontents of the three alkaloids varied significantly among crude aconite roots even insame specie of aconite roots harvested at different time or planted in different districts.It may be the important reason why fatalities from drinking decoction of Aconitumcrude drugs are frequent. Therefore the contents of the three alkaloids must bedetermined in order to guarantee the safety of medicines containing Aconitum roots inclinical or being administrated.