Studies On SFE-CO₂ Of Coumarins In Tradtional Chinese Medicine, And Non-destructive Quanlity Controling Of The Extractives

Supercritical CO2 Fluid Extraction is a newly developed technology for extracting and separating substance. Extracting the natural product with supercritical CO2 can carry out extraction, separation and condense at the same time, and have many advantages, such as low operation cost, no solvent remaining, non- pollution, energy saving, convenient operation, etc. The technology has already been applied in many realms at home and abroad, such as food, spice, petroleum, chemical engineering and the medicine industry, etc. The method which replaces the traditional solvent extraction with supercritical CO2 has been widespread accepted by the industry field. The American Environmental Protection Agency ( EPA) has already regarded the supercritical CO2 fluid extraction technology as the standard method to replace the traditional solvent, especially for the Chinese herbal medicine of the volatile oil or the liposolube substance. Since the production equipments are not commercialized nowadays, which has already serious restricted the development of medicine industry. However , the universale acceptance of this good method and the supercritical CO2 fluid extraction technology has the obvious advantage in this aspect comparing with traditional technology used in Traditional Chinese herbal medicine,.It has evoked public attention to its potential industrial prospect.Traditional extraction method of the effective composition of Chinese herb medicine is as following: cooked by water, extracted by ethanol or ligroin, but these methods has some defects, such as insecurity in operation, low efficiency of extraction, heavy lose of the effective composition, unsteady quantity, and uncertain function of effective composition. The most important defects is: traditional extracting technology tends to result in medical and environmental pollution . However supercritical CO2 fluid extraction technology can overcome the defects and weakness of traditional extraction technology, which is more safe and credible, and has better separation result. Supercritical Fluid Extraction Method (abbreviated as SFE) can be used to extract effective contents from natural herbs, which takes shorter time, needs less materials, and has lower costs. The operation is more controllable, will not cause any pollution or destruction of the sample products.Many medical experts have adopted the advantageous technology of SFE, and called on application of this technology on Chinese herbal medical research and development, and realizing industrialization. SFE can increase the medical level of Chinese herbal medicine system, particularly in solving the difficulties of extraction and separation of volatility and lipiosolube medicine composition efficiently. This technology is more practical and urgent in need. Therefore, adopting the supercritical CO2 technique to extraction is the reform to the traditional Chinese herbal medicine, and has huge applied value to the development of Chinese herbal medical industry.In this paper, the author mainly discusses the application of this method in extracting effective contents from herbs. Taking the extraction of fructus Psoraleae , fructus Cnidii and radix Angelicae dahuricae as the example, the author discussed the technological conditions of SFE-CO2 method, and their effects on extract output rates and effective contents. Near-infrared (NIR) Spectroscopy was applied to test the extractives of Fructus Cnidii by SFE-CO2, establishing ANN models of two active components in extractives, realizing the on-line analyze of drugs.1,The extraction of Psoralen from fructus Psoraleae.Different experimental extraction conditions of extracting pressure, temperature, separating pressure, flow rate of CO2 were studied by supercritical carbon dioxide fluid extraction technology. Orthogonal experimental design was applied to optimize the extracting technical method, according to the effective extracting rate and output contents. Comparing with the traditional extracting method of Psoralen, the extracting rate of Psoralen by SFE-CO2 is increased by 1 time, the operation technique is more simple, and the result is repeatable. Crystal of psoralen can be achieved directly from the extractives by crystallizing. This is a new method to get the psoralen crystal, and the author has applied for state invention patent.2. The extraction and separation of total coumarins from radix Angelicae dahuricae.Orthogonal experimental design was applied to optimize the technical method of SFE-CO2 on radix Angelicae dahuricae. Since the contents of coumarins of natural radix Angelicae dahuricae is low, the effective extractives are also low, the alcohol is added as carrying solvent during extracting. The extraction pressure and the adding of carrying solvent are the main factors on the output rates of extractives, while the extraction temperature and separating pressure have little influences. Thus, the lower extraction temperature and separating pressure were selected.UV was applied to determine the components of coumarins of the extractives from radix Angelicae dahuricae by SFE-CO2, the coumarins account 18.36% of the total extractives. GC-MS method was adopted to analyze the essential oil of radix Angelicae dahuricae and determinate the relative contents. 41 compounds were identified, the measured effective content accounts 96.92% of the total extractives. Compared with the method of distillation, SFE is an efficient and stable method. The author find out that the Imperatorin is unstable to heat. When the coumarins was extracted from radix Angelicae dahuricae by water cooked method, there is little Imperatorin left in the extractives. The content of Imperatorin is decreasing with the extracting time increasing. The extractives extracted by SFE-CO2 reserved the total effective contents. The extracting time was short, the oxidation of naphtha was avoided, and the yield was increased.3. The extraction and separation of total coumarins from fructus Cnidii .Different experimental extraction conditions of extracting pressure, temperature, separating pressure, flow rate of CO2 on fructus Cnidii were studied by supercritical carbon dioxide fluid extraction technology. It has been proved through tests that the yield of extractives increases with the increasing of extraction pressure, the density of CO2, and dissolving rate. The optimum extraction yield comes at 25MPa. The temperature has effect on the extraction yield and the contents of osthol. The total extractives and the contents of the osthol increase with the increasing of the temperature. Through the orthorgonal experimental design analysis, the author found the extraction pressure, extraction temperature, and seperating pressure have great effect on the contents of osthol in the extractives, while the separating temperature has little effect on extraction yield.By optimizing the technical process on extracting of fructus Cnidii , the light yellow green extractives are gotten. The effective total coumarins as osthol and Imperatorin accounts for 43.25% and 21.7% respectively. This extracting technical process can realize the extracting, separating, and purifying directly at the same time. The experimental results proved that the SFE-CO2 is a comprehensive technology of extracting, separating, and condensing. The extractives of fructus Cnidii was indentified by TLC ,and HPLC was applied to determine the components of the total coumarins.The methodology was carried out. It is proved that the method was accuracy, repeatitbility, and high reproducible.Target compound Y was first successfully separated by recrystallization from the extractives of SFE. The compound was identified to be osthol by UV,IR and MS. This technology was applied for state invention patent at present.4. ANN on NIR Spectrum on line determination of the content of extractives of fructus Cnidii by SFE-CO2.The conventional determination of active compounds content by the use of Chinese Pharmacopoeia and State Drug Standard in pharmaceutical analysis often calls for using various analytical techniques, including chromatographies (GC, HPLC) and spectroscopies (IR, UV). However, these methods usually require dissolving the samples, separating them and determining their ingredients, which cost a lot of time and energy. In this paper, the active compounds of fructus Cnidii extractives by SFE-CO2 were determined using back-propagation artificial neural networks(BP-ANN) and NIR spectroscopy. It indicates that the BP-ANN models are convenient, efficient, and have good results.In this paper, five main parameters, namely, input nodes, hidden nodes, momentum, learning coefficient and number of iterations, were optimized and discussed; furthermore, the optimal ANN models were obtained. In order to avoid establishing overfitting models, a new concept, degree of approximation, was cited. The citation of degree of approximation avoids bringing overfitting phenomenon. Some samples were chose to monitor training set while the network is trained, and both training and predicting were optimized at last.The general pretreated methods including first-derivation and standard normal variate (SNV) were studied and discussed in detail in this paper. It indicates that the pretreatment of the original spectrum is necessary.The mathematical correction models of ANN, NIR and shortware NIR in quick determinating the extractives of fructus Cnidii by SFE-CO2 without destroying the samples are established respectively. The forecasting data is identical with the results determined by traditional HPLC, which indicates that the artificial neural networks are powerful in processing complicated non-line data. ANN must have been expansive foreground and applied values in online determination of natural pharmaceuticals.