Study on antioxidant activity of flavonoids extracted from jackfruit skin separated and purified by macroporous resin technology

Flavonoid crude extracts distilled from jackfruit skin were selected as test solution in this study. NKA resin was picked up as the best separation and purification resin from six kinds of macroporous resins with different polarity through static adsorption analysis, meanwhile, the analytical conditions of dynamic adsorption of NKA column chromatography were explored as well. The results showed the optimized parameters of analytical conditions were sample concentration of 0.90 mg/m L, the sample volume of 200 m L, and the elution dose of 120 m L.The best purification process was obtained by the single factor and orthogonal experiments which were 4 m L/min, p H5 and 70% ethanol concentration on sampling and elution flow rate, sampling p H value and ethanol concentration.The recovery rate of flavonoids was as high as 96.02% in this cases.The purity of flavonoids was increased from 16.74% to 84.42% and increased about 4.04 times after post-column, which indicated that NKA resin had a significant effect on the enrichment and purification of flavonoids from jackfruit skin. Results of in vitro antioxidant activity showed that the purified flavone with NKA column chromatography exhibited significantly enhancement with increased purity of flavonoids compared with that unpurified.