Objective: To determine dissolution of different extracts of Scutellariae Radix and investigate its oxidation resistance. Method: According to pre-treatment process to collect extracts of Scutellariae Radix containing different associated substances(The content of baicalin were 19.75%

62.83%

84.55% and 98.0%)

HPLC was employed to determine dissolution of baicalin in each sample with mobile phase of methanol-water-phosphoric acid(47:53:0.2) and detection wavelength at 280 nm.Antioxidant capacity of different extracts of Scutellariae Radix was measured by DPPH

detection wavelength was set at 516 nm. Result: The higher baicalin content in different associated substances

the lower bioavailability;cumulative dissolution rates of these four extracts in 3 h were 38.24%

25.91%

23.49% and 22.98%.With increasing the content of baicalin in extracts

antioxidant capacity increased

there were no obvious changes in antioxidant capacity when the content of baicalin reached above 85%. Conclusion: Different quality and quantity of associated substances have a certain effect on dissolution and oxidation resistance of baicalin.