The Preparation Of Poplar Bud Extract And Study On The Antioxidant Activity

Poplar bud is a branch or flower that is not fully developed and elongated in the Populus plant of Salicaceae.It is a kind of gum source widely found in nature and one of the sources of biologically active compounds.Poplar bud extract is rich in polyphenols,including flavonoid phenolic acid and its ester compounds,which have the functions of regulating immune,protecting liver,inflammation and antisepsis.It can be seen that the research on poplar bud has important development and utilization value.However,at present,there are few functional studies on poplar buds.Based on the single factor experiment,this paper uses the response surface test design method to optimize the extraction process of total flavonoids from poplar buds.In this paper,HPLC-DAD and LC-MS method were used to qualitatively and quantitatively analyze the active constituents of poplar bud alcohol extract.The antioxidative activity of the extract of poplar bud was also determined.The antioxidant activity of poplar bud alcohol extract was evaluated by hydroxyl radical-induced DNA oxidative damage model,which was used to provide a basis for the high value development of poplar bud resources.1?In this paper,the hot extraction method was used to extract the total flavonoids.Based on the single factor experiment,the response surface method was used to optimize the abstraction process of total flavonoids from poplar buds.The best extraction process of total flavonoids from poplar buds was as follows:extraction time 2 h,the ratio of material to liquid1:16?g/mL?,ethanol volume fraction 85%,the extraction rate of total flavonoids of poplar buds under this condition was 13.14%.2.The active components in the extract of poplar bud alcohol were determined by HPLC-DAD and ultra performance liquid chromatography-mass spectrometry.Ten polyphenolic compounds in poplar bud alcohol extracts were identified,namely caffeic acid,P-coumaric acid,ferulic acid,cinnamic acid,quercetin,kaempferol,isorhamnetin,pinocembrin,chrysin,and galangin;the detection line of HPLC-DAD method is 0.04129?g/mL,and the limit of quantification is 0.1375?g/mL.The precision,stability,repeatability and recovery test results show that the method is precise.The content of these 10phenolic compounds ranges from 0.70 g/kg to 36.81 g/kg,and the average content of ginseng,chrysin and galangin is higher;the average content of ferulic acid is the lowest.3.In this paper,the antioxidant activity of ethanol extracts from poplar shoots was evaluated..The IC50 value of poplar bud extract scavenging DPPH free radical was 0.15 mg/mL,and the IC₅₀ value of Vc was 0.023 mg/mL,indicating that poplar bud extract had better scavenging ability to DPPH free radicals.The total antioxidant capacity of poplar bud extract was 152.1gTrolox/kg,manifesting that it has strong antioxidant activity.The poplar bud extract has the ability to complex Fe²⁺,and the complexing force is 271.03 gNa₂EDTA/kg,showing that the poplar bud extract has a good Fe²⁺complexing force.Poplar bud extract has protective effect on oxidative damage of pBR322 DNA.With the increase of extract concentration of poplar bud,94.42%of pBR322 plasmid DNA double helix structure can be protected from oxidative stress damage,which indicates that the extract of poplar bud has a significant protective effect on hydroxyl radical-mediated DNA oxidative damage.