OBJECTIVE To analyze the differences in multi-type resource chemical components and antioxidant activity of Lycium barbarum leaves (LBLs) with different strains and different maturity in order to provide the data support for their resource utilization.
METHODS The content of 19 main chemical components including flavonoids, phenolic acids and alkaloids in the leaves of two L. barbarum cultivars for fruit and leaf (Ningqi No.7 and Ningqicai No.1) with different maturities were determined by UPLC-TQ-MS technology. Free radical scavenging abilities of DPPH and ABTS, and iron ion reducing ability were used to evaluate the antioxidant activity of LBLs.
RESULTS The contents of various components in LBLs with different strains and different maturity were significantly different. The contents of each component in leaf buds and tender leaves were significantly higher than those in young leaves and mature leaves. The LBLs for fruit use have higher rutin content, while the LBLs for leaf use have higher contents of quercetin-3-O-rutose-7-O-glucoside and betaine. All samples showed good antioxidant properties, and the antioxidant activity showed a weakening trend with increasing maturity. The tender leaves of Ningqicai No. 1 had the highest DPPH scavenging ability, and the leaf buds had the highest ABTS free radical scavenging ability and iron reduction ability, while all three were higher in the leaf buds of Ningqi No. 7. The antioxidant activity of LBLs for leaf use was higher than that of LBLs for fruit use. The antioxidant activity of LBLs was significantly positively correlated with the contents of cryptochlorogenic acid, 5-O-feruloylquinic acid, quercetin-3-O-rutino-7-O-glucoside, chlorogenic acid and betaine.
CONCLUSION The content of resourceful components and antioxidant activity of LBLs varies greatly among different strains and different maturity levels. Leaf buds and tender leaves of L. barbarum have higher content of each component and better antioxidant activity, which show higher development and application values. The development and application value of LBLs for leaf use is higher than that of LBLs for fruit use. The results can provide reference for the resource utilization of LBLs with different strains and different maturity levels.
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