| SFE combined with other extraction method was applied to extract matrine-type alkaloids from Sophora Flavescens Ait. in this article, in order to obtain a more efficient, reasonable extraction and separation process of matrine-type alkaloids with low pollution.Firstly, different extraction processes were designed according to the solubility parameter comparison between SC-CO2 and matrine-type alkaloids. Secondly, experiments were carried out to choose the best extraction process with the application of SFE to get high recovery of matrine-type alkaloids. The influences of SFE operation conditions on matrine-type alkaloids recovery rate were also studied. Thirdly, oxymatrine was separated and purified from the total alkaloids. In the end, oxidation reaction was investigated to transform matrine in the mixed matrine-type alkaloids into oxymatrine.In the course of choosing extraction method for matrine-type alkaloids, the following three process routes were investigated: the first route, SFE with addition of modifier; the second route, lipid soluble substances removal with SFE prior to solvent extraction; the third route, SFE with modifier following lipid soluble substances removal with SFE. Compared with solvent extraction method, through the second extraction route the highest matrine-type alkaloids recovery rate of 1.96% has been obtained, which is 2.4 times of the recovery of solvent extraction.Through the second extraction route, Uniform Design was adopted to arrange the experiments and the experimental results were software processed. Two correlation equations has been gained as follow.The correlation equation between SFE extraction rate and extraction conditions: Y1 =1.03 +9.62×10-2X1 -0.61X3+7.46×10-2X32 -1.10×10-3X12 + 2.21×10-6X23-2.72×10-3X33+6.48×10-5X1X2X3Thereinto: Y1 represents SFE extraction rate; X1-X3 represents SFE pressure, temperature and extraction time respectively.The correlation equation between matrine-type alkaloids recovery and SFE extraction conditions:Y2 =-2.11 + 0.133X1 +6.44×10-2X2-2.40×10-3X1X2-8.76×10-4X2X3-3.03×10-3X1X3Thereinto: Y2 represents matrine-type alkaloids recovery; X1-X3 represents SFE pressure, temperature and extraction time respectively.By optimizing the experimental data, the highest SFE extraction rate of 2.3% has been obtained with corresponding SFE conditions 35 MPa, 35℃ and extraction time 8hours. The highest matrine-type alkaloids recovery of 1.96% has been gained with corresponding SFE conditions 12MPa, 75℃ and extraction time 2hours. There are no direct relations between above two SFE conditions.It was compared that the processes of separation and purification of oxymatrine in the mixed matrine-type alkaloids obtained through the second extraction route and solvent extraction. It was concluded that more simplified separation process, more purified oxymatrine and more stable crystal could be obtained applying the second route. Furthermore less organic solvent were consumed and the recovery of matrine-type alkaloids after separation could reach 0.914%, which was 4.5 times of solvent extraction method of 0.212%.The oxidation reaction of total matrine-type alkaloids with second method was studied preliminarily in this paper. The influence of reaction conditions such as reaction temperature, the molar rate of H2O2 compared to mixed matrine-type alkaloids and reaction time on reaction degree was explorerd. Through experiments matrine could be transformed into oxymatrine totally at 60℃ with a molar rate 4:1 of H2O2 compared to total matrine-type alkaloids and reaction time of 24hours. The oxymatrine in the mixed matrine-type alkaloids treated with oxidation was purified and a purity of 75.23% was achieved.A series of qualitative and quantitative analysis methods were applied on different steps of the extraction and purification of matrine-type alkaloids from Sophora Flavescens Ait. : Acid-base titration to determine the content of total matrine-type alkaloids in extract; Thin-layer chromatography (TLC) to distinguish the types of alkaloids in the mixed alkaloids; Gas chromatography-mass spectrum (GC-MS) to quantify the ingredients of SFE extract; High Performance Liquid Chromatography (HPLC) to mensurate the purity of the oxymatrine crystal.The innovation point of this paper is that SFE has been applied as an assistant means on the material seedtime of the extraction of matrine-type alkaloids from Sophora Flavescens Ait.. SFE has been used to remove the lipid- soluble ingredients to supply a more clear material for later extraction and purification processes. The experimental results demonstrate that the recovery of matrine-type alkaloids has been remarkably enhanced in later extraction procedure.
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