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.