Isolation and purification of matrine and oxymatrine and TLC identification of Radix Sophorae Tonkinensis

OBJECTIVE To isolate and purify the two alkaloids matrine and oxymatrine and then to identify the commercial medicinal material of by TLC. METHODS Matrine and oxymatrine were isolated from the roots of Sophora tonkinensis by repeated silica gel column chromatography and purified by recrystallization method. Their structures were elucidated on the basis of physical and chemical properties and spectral data, and the purities of these two compounds were determined by TLC and HPLC analysis. The crude drugs of from different sources were identified by TLC using matrine and oxymatrine as the reference substances. RESULTS 1.7 g of matrine and 2.0 g of oxymatrine with the purity of more than 98% were prepared. The genuine samples of Shandougen were differentiated from the adulterations by TLC method. CONCLUSION Matrine and oxymatrine are suitable to be used as the reference compounds for the TLC identification of Shandougen.