Purification of total flavonoids from loquat leaves by macroporous resin and corresponding antioxidant capacity

Flavonoids is one of the major active compounds in loquat leaves. In this study, the purification process of total flavonoids in loquat leaves by macroporous resin was researched and the antioxidant activity of total flavonoids was determined. The active compounds were extracted by 95% ethanol, and the total flavonoids was purified by macroporous resin. Comparing the static and dynamic adsorption and desorption characters of 6 macroporous resin, the best type of macroporous resin was determined. The desorption-solvent was determined by the gradient elution. Moreover, DPPH and FRAP analysis methods were used to determine the antioxidant activity of total flavonoids in this study. The result showed that X-5 was the optimum macroporous resin to purify the total flavonoids of loquat leaf. After adsorbed by X-5 macroporous resin, removing impurity with 15% ethanol and desorbed with 65% ethanol, the total flavonoids purity of the eluate was 82.20%, the purification factor was 2.14 times and the recovery was 81.08%, and the macroporous resin should be regeneration after using 3 times. As the flavonoids content of extraction increase, its antioxidant activity increase. In summary, the X-5 macroporous resin was suitable to purify the total flavonoids of loquat for higher purification fold and higher recovery. Purified extract had higher content of flavonoid and better antioxidant activity, it suggested the flavonoids played an important role in antioxidant activity.