Abstract:

This study was aiming to study the chemical composition of flavonoids of ethanolic extract of Epicarp of Nelumbo nucifera Gaertn as well as its antioxidant activity. The ethaonolic extract of lotus Epicarp was isolated using macroporous resin and Toyopearl HW-40S gel column to acquired 6 compounds (LF-F1～LF-F6). The composition and structure of LF-F2 was analyzed by HPLC and LC/MS and the antioxidant activity was measured by chemiluminescence. Results showed that total flavonoids accounts for 94.1% of the extracts (60% ethanol) of lotus Epicarp. Flavonols of LF-F2 comprised quercetin, myricetin, kaempferol, isorhamnetin and so on. IC50 for LF-F2 to superoxide anion radical, hydroxyl radical and hydrogen peroxide were 420, 40, 0.6μg/ml, respectively. The existence of rutin in LF-F2 was identified for the first time. Fraction LF-F2 possessed good antioxidant activity in a dose dependent manner.

Key words: flavonoid, isolation and purification, antioxidant activity, chemiluminescence