Abstract: The antioxidant and antibacterial activities of total flavonoids from different parts of Sedum aizoon L were studied in this paper.Antioxidant activities of total flavonoids from tender leaves,old leaves,stems and flowers of Sedum aizoon L  were evaluated by reducing power on Fe³⁺,DPPH and Hydroxyl Radical scavenging activity assays. Escherichia coli,Staphylococus aureus and Bacillus subtilis were used as experimental strains,the antibacterial activity of different parts were determined by the method of double dilution tests.The results showed that the Ferric Reducing Antioxidant Power,DPPH and Hydroxyl Radical scavenging activity of total flavonoids in different parts of Sedum aizoon L.were significantly higher than L-ascorbic acid.The Ferric Reducing antioxidant power of total flavonoids in different parts of Sedum aizoon L.could reach up to 810 μmol TE/mL and the IC₅₀ values of DPPH free radical clearance and Hydroxyl Radical scavenging activities for stems and flowers were 0.8 and 14 μg/mL,respectively.The total flavonoids in various parts of Sedum aizoon L.had certain antibacterial effect,and the inhibitory effect on Staphylococcus aureus was better.The antibacterial effect of total flavonoids in different parts had good inhibitory effect on Staphylococcus aureus;The antibacterial effect of total flavonoids in stems and tender leaves to Escherichia coli was significantly better than old leaves and flowers;While the antibacterial effect of total favonoids in the old leaves to Bacillus subtilis was a little better than other parts.The results can provide a scientific basis for the utilization of total flavonoids from different parts of Sedum aizoon L.

Key words: Sedum aizoon L., flavonoid, antioxidant, antimicrobial activity