Preparation of Total Flavonoids from Stem and Leave of Scutellaria Baicalensis<\i>

OBJECTIVE To optimize the technology of preparing total flavonoids from the stem-leave of Scutellaria Baicalensis and provide basis for the rational utilization and development of stem-leave resources of Scutellaria Baicalensis. METHODS The transfer rates of 8 flavonoids compounds in the stem-leave of Scutellaria Baicalensis and the single factor combined with orthogonal design were applied to optimize the extraction process. In addition， the transfer rates of acid deposition and macroporous resin method to purify total flavonoids in the stem-leave were compared， and the purification technique of macroporous resin method was optimized. RESULTS The best extraction technology was to use 12 times amount of 40% ethanol with heat reflux， one time an hour. According to the result of purification of extraction， the transfer rate of total flavonoids in the stem-leave of Scutellaria Baicalensis with macroporous resin method was 92.53%， higher than that with acid deposition， 76.69%. When pH value was 1.01， with acid deposition， the transfer rate of compounds such as scutellarin was over 90%， while the transfer rate of enriched dihydroflavanone was quite low， for instance， 64.76% for isocyanin-7-O-β-D- glucuronide and 68.75% for safflower-7-O-β-D-glucuronide. However， as for macroporous resin method， the transfer rate could come up to over 90%， which promoted the efficient transfer of each target component. On the basis of optimum， the resource volume was 2.08 g dry extract per 10 g HP-20 type dry resin with 0.26 g/mL liquor. The ratio of resin column diameter to height was 1∶3. The perfect purification technology was to wash the sample with 4 BV of distilled water and eluted with 4 BV of 30% ethanol， which could obtain 66.03% mass fraction of total flavonoids. CONCLUSION This study establishes a firm and environmental-friendly method of preparing total flavonoids from the stem-leave of Scutellaria Baicalensis and provides some reference for the further development and utilization of the stem-leave of Scutellaria Baicalensis.