Antioxidants from Pedicularis longiflora var. tubiformis (Klotzsch) P. C. Tsoong

An efficient method for the screening and isolation of potent antioxidants from a tibetan medicinal plant by employing online HPLC–DPPH assay combined HSCCC has been successfully established. Six major constituents : boschnaloside ( 1 ), alyssonoside ( 2 ), leucosceptoside A ( 3 ), isoverbascoside ( 4 ), leucosceptoside B ( 5 ) and verbascoside ( 6 ) were isolated and purified from the water extract by HSCCC using ethyl acetate-n-butanol-water as two-phase solvent system. The results indicated that the combination of the online HPLC–DPPH assay with HSCCC could be suitable for the screening and separation of antioxidant compounds from extract of this plant or other medicine plants.