Antioxidant activity of ethanol extract of Lycium barbarum's leaf with removal of chlorophyll / 한국영양학회지

ABSTRACT

PURPOSE: The aim of this study was to estimate the antioxidant activities of 50%, 70%, and 100% ethanol extracts of Lycium barbarum leaf and chlorophyll removal extract. METHODS: The antioxidant activities were estimated by measuring total polyphenol content and by assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfate) (ABTS) radical scavenging activities and ferric reducing antioxidant power (FRAP). In addition, reactive oxygen species (ROS) production, DNA fragmentation, and antioxidant enzyme (superoxide dismutase and catalase) activities of the extracts were measured in hydrogen peroxide (H2O2)-stressed HepG2 cells. RESULTS: The total polyphenol content, DPPH and ABTS radical scavenging activities, and FRAP value of the extracts increased in an ethanol concentration-dependent manner. The antioxidant activities of the chlorophyll-removal extracts were much higher than those of the chlorophyll-containing extracts. Cytotoxicity was not observed in HepG2 cells with extracts up to 1,000 µg/mL. All extracts inhibited ROS production in a concentration-dependent manner from 31.3 µg/mL and inhibited DNA damage at 250 µg/mL. The SOD and catalase activities of cell lines treated with the extracts and H2O2 were similar to those of normal cells, indicating a strong protective effect. CONCLUSION: Lycium barbarum leaf extracts had high antioxidant activities and protected H2O2-stressed HepG2 cells. Since the chlorophyll-removal extract exhibited higher antioxidant activities than the chlorophyll-containing ones and the cytoprotective effect was similar, chlorophyll removal extract of Lycium barbarum leaf could be developed as ingredients of functional food and cosmetics.