Extraction,Antioxidant And Antibacterial Properties Of Polyphenols From Chaenomeles Sinensis(Thouin) Koehne

Chaenomeles Sinensis(Thouin)Koehne(C.Sinensis)is widely grown in China with abundant polyphenols.Further study on the extraction,purification and biological activity of polyphenols from C.Sinensis has theoretical and practical significance to promote its further processing and utilization.In this paper,polyphenols from C.Sinensis were extracted by enzymolysis assisted ultrasound and purified by macroporous resin.On this basis,the antioxidant and antibacterial properties of C.Sinensis were studied.The main conclusions of this research were as follows:1.The optimal extraction conditions of polyphenols from C.Sinensis included:enzymatic hydrolysis time 55 min,ethanol concentration 59%,liquid to material ratio 1:28,enzyme dosage 20?L/g,enzymatic hydrolysis p H 3.4,enzymatic hydrolysis temperature 65?,ultrasonic liquid to material ratio 1:30,ethanol concentration 60%,ultrasonic time 40 min,ultrasonic temperature 55?.The extracted content of C.Sinensis polyphenol under this extraction process was 62.07 mg/g.2.The AB-8 resin had the best purification effect,and the best adsorption conditions were as follows:polyphenol concentration 3.0 mg/m L,sample solution p H 3,sample loading flow rate 1.0 m L/min,sample loading volume 70 m L.The best elution conditions included volume fraction of eluent ethanol concentration 50%,eluent flow rate 1.0 m L/min,eluent volume 120 m L.Under these conditions,the purity of C.Sinensis polyphenols increased from28.86%to 69.11%,increased 1.39 folds.3.There was a dose-effect relationship between the total reducing power of C.Sinensis polyphenol extract and the scavenging ability of DPPH radicals and ABTS radicals.The order of the scavenging ability of DPPH radicals was:Vc>purified polyphenols>unpurified polyphenols,IC₅₀ values were 4.79,5.01 and 29.51?g/m L,respectively.The order of the scavenging ability of ABTS radicals was:purified polyphenols>Vc>unpurified polyphenols,IC₅₀ values were 8.51,9.55,125.89?g/m L,respectively.The total reducing power of Vc was greater than that of purified polyphenols,and greater than that of unpurified polyphenols.4.The antibacterial effect of C.Sinensis polyphenols against Staphylococcus aureus and Bacillus subtilis was better,but the effect against Escherichia coli was poor.Under this experimental conditions,the minimum inhibitory concentration was 0.78,0.78,6.25 mg/m L,respectively.After being treated with C.Sinensis polyphenols,the cell morphology of Staphylococcus aureus and Bacillus subtilis was changed,and the cell integrity was severely damaged.The contents of extracellular nucleic acid,extracellular protein and?-galactosidase,and the activity of alkaline phosphatase were significantly increased.The normal cell metabolism was affected,which eventually led to the lysis and death of bacteria.