Separation of Alkaloids in Sophora flavescens Ait.by Aqueous Two-phase Extraction
双水相萃取分离苦参生物碱

Using ethanol,polyethylene glycol and Triton X-100 combined with inorganic salts separately,several aqueous two-phase systems were developed,including ethanol/(NH4)2SO4 and PEG/(NH4)2SO4,and Their properties and capacities investigated.The results showed that ethanol/(NH4)2SO4 system easily formed,being stable for fast and high rate extraction of alkaloids such as oxymatrine and matrine.The effects of amounts of ethanol and(NH4)2SO4,pH value,temperature and extraction time were optimized further for the ethanol/(NH4)2SO4 system.Their optimal values were 38%(ω) of ethanol,18%(ω) of(NH4)2SO4,pH=7.0,30℃,and 15 min under electromagnetic stirring.The partition coefficient K and extraction rate for oxymatrine and matrine were up to 4.46 and 5.10,and 96.17% and 95.74%,respectively.Adding a certain amount of ethanol and(NH4)2SO4 in the sample extracted by water,the aqueous two-phase system directly formed for extraction of oxymatrine,N-oxysophocarpine,sophoridine,matrine and sophocarpine from it.The first extraction rate of five alkaloids was between 91.03% and 94.46%,and total extraction rate from 97.22% to 98.78% after three times of extraction.Ethanol/(NH4)2SO4 system was successfully applied to purify alkaloids in the aqueous sample extracted from Sophorae flavescens Ait.The relative contents of alkaloids above were increased by more than one times,and those of impurities removed significantly.The extraction of alkaloids was a spontaneous process of endothermic and entropy increase because of less than zero of △H0,greater than zero of △S0 and less than zero of △G0,respectively.