| Recent pharmacology researchs indicate that the alkaloids from Morus alba L. leaves can lower the blood sugar level effectively.1-deoxynojirimycin(DNJ),a representation of these alkaloids,is the main activity component which can cure the diabetes.In this paper,DNJ was investigated in the aspect of detection method, isolation and purification technology from Morus alba L.leaves.(1) A rapid and reliable method suitable for determination of DNJ in Morus alba L.leaves has been developed.DNJ in 100mg dried leaves was double-extracted in 10ml aqueous 0.05M HCI,derivatized by 6-aminoquinoIyI-N -hydroxysuccinimidyl carbamate in pH=8.8 K3BO3 buffer,and analyzed by using RP-HPLC equipped with a fluorescence detector.The linearity ranged from 0.5-25mg/L.The detection limit was 0.02mg/L.The average recovery was 97.4%.(2) Utilizing orthogonal test to gain an optimum extraction condition,with the extract rates of DNJ and total flavonoids as indexes,the optimized parameters were obtained as follows:the ratio of ethanol in extract solution was 60%,ratio of solid to liquid was equal to 1:10,extract time is 2h.extract temperature is 80℃, extracting 2 times continuously,the final extract rate of DNJ from Morus alba L. leaves was 78.6%.DNJ content in dried powder was 0.24%.(3) AB-8 macroporous resin and 732H type cation exchange resin were used to purify sequentially,with the content and recovery rate of DNJ as indexes.It was indicated that AB-8 resin was suitable for the preliminary isolation of DNJ.732H type cation exchange resin chromatography was used to purify in the second step. Elution order is:1 BV H2O——15 BV 0.3 M NH3——2BV 0.5 M NH3.The final total DNJ content in dried powder was increased to 14.8%. |
