No abstract

Genkwanin, a flavonoid which has anti-oxidant and anti-tumor activities, was isolated and purified from flowers of Daphne genkwa Sieb. et Zucc. in a large-scale by normal-phase flash chromatography (NPFC). Dried flower buds were extracted with methanol at room temperature and concentrated. The residues were suspended in water and first extracted with petroleum ether, and then chloroform. Genkwanin was concentrated in the chloroform and insoluble fractions. Under the target-guidance of thin layer chromatography (TLC) as well as solubility, a solvent system composed of cyclohexane-acetone (22:3, v/v) was selected. At a flow rate of 30 mL/min,the insoluble and chloroform fractions were separated to yield 1.5 g and 1.35 g of genkwanin with high purities of 98.3% and 98.6% by HPLC analysis, respectively. The chemical structure of the compound was identified by ESI-MS and NMR. Results of the present study indicated that NPFC was a large preparative-scale, speedy and simple process separation technology and it was feasible to find the appropriate proportion of solvent system by transformation from TLC condition.