Studies On Extraction,Purification And Biological Activities Of Flavonoids From Gynura Procumbens

Gynura procumbens is a new resource food with many functional effects and in this experiment,we are aimed to study the extraction of flavonoids from Gynura procumbens as well as its biological activities,such as antibacteria,antioxidant and anticancer effects.And the study results were as followings:(1)Based on the response surface analysis with the Design-Expert software program,the optimal extraction conditions were:extraction temperature 63°C,extraction time 48 min,ethanol concentration 54%,ultrasonic power 112 W.And in this conditions,the theoretical extraction rate of total flavonoids was up to 4.17%.(2)According to adsorption and desorption,HPD500 was selected as the following purification resin from 8 kinds of macroporous resins,and the optimum purification conditions were obtained by single factor analysis: the sample solution p H=6,sample volume 25 BV,sample concentration 1mg/m L,adsorption at room temperature,50% ethanol solution elution,elution flow rate 1m L/min,elution volume 6BV.(3)The extraction layers were added to resin,then gradient eluted respectively with 10%,30%,50%,70% and 90% ethanol solution,and the total flavonoids of every elution layer were determined.The experiment results were as followings: n-butanol layer resin column eluting with 30% ethanol(30%EBR)74.01%,n-butanol layer resin column eluting with 50% ethanol(50%EBR)62.64%,ethyl acetate layer resin column eluting with 50% ethanol(50%EER)82.04%,ethyl acetate layer resin column eluting with 70% ethanol(70%EER)72.6%,petroleum ether resin column eluting with 90% ethanol(90% EPR)13.14%,water resin column eluting with 90% ethanol(90% EWR)10.14%.The content of flavonoids in 10% ethanol elution was very little.(4)The antibacterial activity was tested by filter paper method.The results showed that the antibacteria intensities were positively correlated with the total flavonoids content.50% ethyl acetate layer had the best bacteria inhibited effect.All the tested compounds had good inhibitory effect on Escherichia coli and Staphylococcus aureus,while no inhibitory effect on fungi.And the antibacterial activity was as followings: 50%EER > 30%EBR >70% EER > 50%EBR.(5)Antioxidant activity of elution layers research.The study investigated on DPPH free radical(DPPH·),hydroxyl radical(·OH)and superoxide anion radical(·O2–)removal ability as well as their reducing power.The results showed that the antioxidant activity was positive to the content of total flavonoids,and antioxidant capacity of each extraction layer was as followings: 50%EER > 30%EBR > 50% EBR > 90%EWR.(6)Anti-colon-cancer activity of elution layers research.The drug concentration of 0.125, 0.25,0.5,1.0 mg/m L were used to intervene Caco-2 cancer cells in vitro,and MTT study found that all layers has a certain anti-cancer effect and the total flavonoids content was positively related.The drug concentration of 0.5 mg/m L intervention could achieve the best inhibitory effect,which is approximately up to 90%.The anti-cancer ability is as followings: 50%EER > 70%EER > 30%EBR > 50%EBR > 90%EPR.The protein expression levels of Cas3 and Bax apoptosis promotion genes and Bcl-2 apoptosis suppression gene were studied in Western blot experiment,in general,Cas3 and Bax were increased while Bcl-2 was downregulated.These results indicated that Gynura procumbens regulated the apoptosis of colon cancer cells by regulating the expression of the related apoptosis proteins.