Skullcap Scutellaria Glycosides Extraction Separation And Determination Methods

On the basis of the literatures, the extraction, separation, purification anddetermination methods of baicalin from Scutellaria baicalensis were studied. Specificsummary as follows:Extraction of baicalin. The methods of decoction extraction, reflux extraction, ultrasonic wave extraction and microwave-assisted extraction of baicalin fromScutellaria baicalensis were studied systemically. Microwave-assisted extraction waschosen for its high extraction yield of baicalin. And the optimal parameters weretaking 5g Scutellaria baicalensis to the 100mL solvent (ethanol: water=60: 40, v/v)soak for 2 hours. The extraction time was 80s. Under this condition, the yield ofbaicalin was 5.71%.Separation and purification of baicalin. First, crude baicalin was obtained byadding hydrochloric acid to extraction solution. The baicalin was purified bycrystallization; The aqueous two-phase extraction was established to purify. Theoptimal conditions were following: gather glycol (PEG) 6000 for 26% (wt%), K₂HPO₄, 18%; pH=7, the temperature, 30℃. Then total recovery was 98.6%.Determination of baicalin. Method of infrared spectrum was established toidentify baicalin.At the absorption wavelength of 278nm, ultraviolet spectra was used fordetermining baicalin samples. The determination of baicalin was linear in8.0×10^-3mg/mL～6.0×10^-2mg/mL.HPLC (High Performance Liquid Chromatography) was used to determinebaicalin. The analysis conditions were following: column, VP-ODS C₁₈(150mm×4.6mm); mobile phase, methanol-water- phosphoric acid=47: 53: 0.2(v/v/v); Detection wavelength, 278 nm; Flow rate, 1.5 mL/min; Column temperature, 25℃.The determination ofbaicalin was linear in 8.0μg/mL～52μg/mL.Conclusion was drawn after comparing the two determining methods: Theprecision and accuracy of UV was satisfactied.