Separation of bioactive compounds from dark tea prepared from Camellia sinensis var. baiye dancong using HSCCC target-guided by α-glycosidase inhibitory activity

α-glycosidase inhibitors in dark tea were studied systematically by the method of a combination of extraction with 60% ethanol, fractionation on D101 column, and further purification by HSCCC ordinally. The result showed that fractions D-6, D-7 and D-8 obtained by D101 column chromatography indicated higher inhibitory activity than 60% ethanol extract of dark tea in the concentration 25μg/mL, inhibition were 69.31%、77.53% and 75.23%, respectively. Fraction D-7 was selected to further separation by HSCCC with solvent system ethyl acetate-n-buthanol-methanol-water-acetic acid (4∶1∶1∶4∶0.1, v/v) . Compound 1 (vitexin) and compound 2 (isovitexin) were obtained by one step HSCCC separation with purities higher than 95%, respectively.