The efficiency of flavonoids in polar extracts of Lycium chinense Mill fruits as free radical scavenger

The extracts of Lycium chinense Mill fruits with water, 50% ethanol and 95% ethanol were compared in antiradical efficiency according to the Chinese consumption tradition. The results showed that water infusion was similar to 50% ethanol extract in flavonoids (1154 +/- 89 and 1207 +/- 66 mg kg(-1), respectively), 95% ethanol extract contained more flavonoids (1497 +/- 70 mg kg(-1)). The main flavonoids in Lycium chinense Mill fruits were rutin and chlorogenic acid in water extract, rutin and protocatechuic acid in 50% ethanol extract and rutin in 95% ethanol extract as determined with high-performance liquid chromatography (HPLC). All extracts showed a slow kinetics in DPPH. antiradical reaction system. The antiradical efficiency of the extracts tended to become stronger as the polarity of the solvents decreased. (C) 2003 Elsevier Ltd. All rights reserved.