Study on extracting purified active components of Picria fel-terrae , Scutellaria baicalens is andPhellodendron chinense with macroporous resins Chemical constituents of Picria fel-terrae RP-HPLC fingerprint of Picria fel-terrae from South Guangxi Study on purification of total saponins in Picria fel-terrae with D101 macroporous resin