Comparison of Extraction for Alkaloids from Sophora flavescens by Different Microwave Assisted Method

Objective:To compare differences of pressurized microwave-assisted extraction method(PMAE),focused microwave-assisted extraction method(FMAE) and post microwave irradiated-reflux extraction method(PMIRE) in extracting alkaloids from Sophora flavescens,and investigate extraction process and microwave mechanism of these 3 kinds of microwave assisted extraction methods.Method: With oxymatrine and matrine as target alkaloids,which were determined by HPLC,thermodynamic functions were calculated by optimizing microwave power,extraction temperature,extraction time,solid-liquid ratio,medicinal granule and other factors,surface structural change of herbs was observed by electronic scanning microscope.Result:Compared with conventional solvent reflux extraction(SRE),extraction efficiency of PMAE,FMAE and PMIRE increased significantly,ΔH°and ΔS°of alkaloids increased obviously,but ΔG°became smaller.Microwave irradiation could enable cell wall of herbs surface structure to rupture,and strengthen extraction process.Conclusion: Extraction efficiency of alkaloids from S.flavescens with microwave assisted extraction was superior to SRE;Extraction efficiency had large differences by different microwave assisted manners,irradiation degree and extraction process;PMAE had shortest extraction time in the closed system;Because of strong microwave direct role,PMIRE had the best cell-rupture and extraction yield,and its equipment was simple and easy-operating.