Abstract: The contents of total flavonoids in roots, leaves and flowers of Lythrum salicaria L. and their antioxidant and hypoglycemic activities in vitro were investigated. The content of total flavonoids was determined by the aluminum nitrate method. The antioxidant activity in vitro was evaluated by iron ion reduction ability, DPPH （1,1-diphenyl-2-trinitrophenylhydrazine） and ABTS （2,2′-biphenyl-1-amino-trimethylhexahydrocation） free radical scavenging ability. The hypoglycemic activity in vitro was evaluated by the inhibition of α-glucosidase and α-amylase. Pearson method was used to analyze the correlation between total flavonoid content and activity. The results showed that the content of total flavonoids in Lythrum salicaria L. flowers was the highest [（36.80 ± 0.10） mg RT/g], the DPPH free radical scavenging ability [IC₅₀（0.009 1±0.000 3） mg/mL], ABTS free radical scavenging ability [IC₅₀（0.074 4±0.002 0） mg/mL], iron ion reduction ability [（2 670.78± 9.43） μmol VC/g] and the inhibition of α-glucosidase [IC₅₀（0.567±0.012） mg/mL] were the strongest. The inhibitory effect of Lythrum salicaria L. roots on α-amylase [IC₅₀（0.051±0.003） mg/mL] was the strongest. The content of total flavonoids in roots, leaves and flowers of Lythrum salicaria L. was highly significantly positively correlated with antioxidant activity and significantly positively correlated with hypoglycemic activity. Lythrum salicaria L. flowers showed strong antioxidant and α-glucosidase inhibitory effects, and the root had strong α-amylase inhibitory effects.

Key words: Lythrum salicaria L., total flavonoids, antioxidant activity, hypoglycemic activity