| "Kushen"the dried roots of Sophora flavescesn Ait. is derived from Sophara plants. It's well known that alkaloids and flavonoids are rich in Sophora flavescesn. Modern pharmacological studies had demonstrated that matrine type alkaloids possess antitumor, anti-hepatic cancer and have positive effects for viral pepatitis. Microwave-assisted Extraction, which included advantages such as rapidly, less time consumption, less organic solvent consumption, less environment pollution and so on, had been used widely in the extraction of active components in the herbs. In this paper, different MAE methods such as Pressurized Microwave-assisted Extraction (PMAE), Focused Microwave-assisted Extraction (FMAE) and Microwave Irradiated Solvent Reflux Extraction (MISRE) were used for the extraction of alkaloids form Sophora flavescesn. Matrine and oxymatrine were set as target components, the experiment conditions such as microwave power, extraction temperature, granularity, solid solvent ratio and so on were optimized through HPLC analysis. The mechanisms in the process of extraction of alkaloids were also investigated. The extract from Sophora flavescens were separated and purified further by cation exchange resin coupled with macroporous adsorption resin. The results were showed as following:1. Single factor test were used for optimizing the experimental technology of PMAE, MISRE and FMAE using ethanol as extracted solvent. A RP-HPLC analytic method was established to monitoring the contents of matrine and oxymatrine extracted from Sophora flavescens. Obtained optimium conditions of PMAE, MISRE and FMAE were following: for PMAE, microwave power 780 W, particle size 80 mesh, ratio of solid and liquid 1:25, extraction time 5 min; for MISRE, microwave power 60%, microwave-irradiated time 90 s, particle size 100 mesh, ratio of solid and liquid 1:30, extraction temperature 90℃, extraction time 45 min; for FMAE, microwave power 40%, particle size 120 mesh, ratio of solid and liquid 1:40, extraction time 45 min. In contrast to solvent reflux extraction (SRE), microwave-assisted extraction methods had higher yields for matrine and oxymatrine with less extrated time, microwave irradiation could intensify the extraction process of alkaloids from Sophora flavescens.2. The kinetic characteristics of PMAE, MISRE and FMAE were investigated. The results showed that extraction of matrine and oxymatrine from Sophora flavescens by MISRE and FMAE was in accordance with one order of kinetic reaction. PMAE process was based on the cell-rupture process. MISRE and FMAE processes were based on the internal mass-transfer mechanism. Based on the experimental data in SRE, MISRE and PMAE for matrine and oxymatrine, the extraction mechanisms were thermodynamically were also discussed, and the thermodynamic functions were calculated. Results showed thatΔH°andΔS°were greater than zero, the three extraction processes were endothermic and entropy increase. Compared with SRE,ΔH°andΔS°of PMAE and MISRE were greater, of matrine became smaller because microwave irradiarion led cell structure changed. Thus the result of the oxymatrine was diffirent from matrine. In the extraction process for oxymatrine, there was not only diffusion dissolution effection, but also accompanied with complex chemical reaction.3. The static adsorption test results indicated that 001×732 resin and BS-65 resin including some advantages such as adsorption rapidly, large adsorption capacity and so on. Their adsorption isotherm test data fitted well to the Langmuir and Freundlich equations. The adsorption process was a monolayer adsorption. Alkaloids extracted from Sophora flavescens were separated and purified as follow: The sample solution was adjusted to pH2, and fed onto 001×732 resin, 1 mol/L NaCl solution was used in eluention of alkaloids at the flow rate of 2 mL/min; the eluents was adjusted to pH10, alkaloids were adsorbed onto BS-65 resin at flow rate of 2 mL/min, then diethyl ether was used to elute mateine and 50% ethanol aqueous was used to elute oxymatine. After resin separation, the purities of mateine and oxymatrine in the obtained product were 67.2% and 66.8% respectively. The product was putified furthermore with basic aluminum oxide column. The qualification of crystallization was identifed by IR, MS and 1HNMR, the purities of matrine and oxymatrine in two crystals purified were 94.8% and 98.6% respectively though HPLC analysis. |
