Analysis of chemical compositions and antioxidant activities of Lycium barbarum bud and leaf teas

The extracts of Lycium barbarum bud and leaf teas were prepared by hot water extraction ( ratio of solid to liquid1∶ 40, temperature 96 ℃, extraction time 30 min) and their chemical contents were determined, and compositions of free amino acids in Lycium barbarum bud and leaf teas were analyzed by HPLC.Furthermore, the antioxidant activities of Lycium barbarum bud and leaf tea were evaluated by determining of scavenging activities on DPPH radical, ABTS radical and superoxide radical and total reducing power.The results showed that the total polyphenols contents for Lycium barbarum bud and leaf teas were6.32% and 2.96%, respectively. Asp ( 3230.41 and 2440.96 μg/g) , Asn ( 3754.77 and 3495.57 μg/g) , His ( 5585.26 and2825.17 μg/g) and Leu ( 4376.09 and 1051.00 μg/g) were relatively abundant in Lycium barbarum bud and leaf teas.Moreover, both Lycium barbarum bud tea and leaf tea exhibited favorable scavenging activities on DPPH ( IC50: 147.63 and 241.23 μg/m L) , ABTS ( IC50: 109.87 and 145.32 μg/m L) and superoxide radicals ( IC50: 46.58 and 54.32 μg/m L) . Compared with Lycium barbarum leaf tea, Lycium barbarum bud tea showed relatively higher antioxidant activity.