Abstract: Contents of polysaccharides,polyphenols and flavonoids in leaves and fruits of Lycium barbarum were determined by phenol-sulfuric acid method,Folin-Ciocalteu reagent method and AlCl₃ colorimetric method,respectively.Antioxidant capacities of different extracts from L.barbarum were evaluated by ABTS ［2,2′-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt］ and DPPH (1,1-diphenyl-2-picrylhydrazyl) assays.In addition,the inhibitory activity against DNA damage of leaves and fruits were analyzed using plasmid DNA method.Concentrations of bioactive constituents varied across different extracts from leaves and fruits.Antioxidant activities of leaves were higher than those of fruits.Methanol extract from leaves and fruits possessed the lowest EC₅₀ value (ABTS:0.69,2.04;DPPH:0.03,0.52),followed by ethanol extract (ABTS:0.70,2.08;DPPH:0.04,0.57) and aqueous extract (ABTS:0.95,2.08;DPPH:0.05,0.62),which suggested the highest antioxidant activity of methanol extract.DNA damage protection activity of methanol extract from leaves was higher than that from fruits.Antioxidant capacity and inhibitory activity against DNA damage of leaves and fruits was possibly attributed to their polyphenols and flavonoids.The present research was helpful for the scientific exploitation and comprehensive utilization of L.barbarum resource.

Key words: Lycium barbarum leaf, Lycium barbarum fruit, extract;antioxidant activity, DNA damage, bioactive constituent