Studies On The Extraction And Purification Technology And Antioxidant Ability Of Total Flavonoid From Bitterleaf

Bitterleaf is the leaf of the Vernonia amygdalina Del.originated in Africa.In recent years,it have been introduced wildly to the southeast coastal areas of the mainland.The taste of South Africa leaves are bitter,cool,and have the effects of heat-clearing,detoxifying,cooling,cooling,and blood clearing.It has great potential in development in the extraction of medicinal ingredients,health products,and diets.This topic focus on South African leaves,generates the extraction,purification and antioxidation of total flavonoids,and provides the preliminary theoretical basis for the in-depth development.(1)The solvent method and microwave-ultrasonic assisted method is used to extract the flavonoids.NaNO2-Al(NO3)colorimetric method is applied to quantitatively analyze the total flavonoids in the leaves of South Africa by the plant flavonoids detection kit.Comparing the extraction efficiencies of the two methods,we conclude that the solvent concentration,solid-liquid ratio,and extraction time are the same.Under same experiment conditions,the microwave-ultrasonic co-assisted extraction method has significantly higher performance than the solvent extraction method,yield up to 2 times that of the solvent method,and has good precision,reproducibility,sample recovery and color stability,so we use microwave-ultrasonic co-assisted method as the total extraction flavonoids method.(2)Microwave-ultrasonication assists the extraction of total flavonoids from leaves of South Africa.Through the six factors(solvent concentration,material-liquid ratio,microwave power,ultrasonic power,extraction time and extraction temperature)five levels of single-factor tests are conducted.Combining with response surface analysis to optimize the analysis,the optimum process conditions is determined.The results show that the best parameters of the process are ethanol concentration 70%,solid-liquid ratio 1:30,microwave power 400W,ultrasonic power 600W,extraction time 15min,extraction temperature 30℃.Under these conditions,the actual extraction rate is 3.08%。(3)Through the measurement of five different types of macroporous resin X-5,HP20,D101,AB-8,NKA-9the adsorption amount and resolution of total flavonoids in South Africa,the screening conditions are easy to meet,and the cost is low.The macroporous resin X-5 with obvious effects is developed to purify the crude extract.The optimal process parameters were:sample solution concentration 5mg/mL,sample flow rate 2BV/h,sample qiantity 3BV,sample solution ph=6,eluent concentration 70%,eluent flow rate 2BV/h,dosage of eluent 4BV.Purity of purified total flavonoids from bitterleaf can be achieved as 38%。(4)Comparing with L-Ascorbic Acid,the method is used to measure the total antioxidant capacity,the ability to scavenge hydroxyl radicals,the ability to scavenge superoxide anion,and the ability to scavenge DPPH free radicals.The experimental results show that the flavonoids in South African leaves has good antioxidant activity,1.44 times as L-ascorbic acid,and is able to remove superoxide anion,DPPH free radicals and hydroxyl radicals.At the same concentration,the clear ability of total flavonoids from bitterleaf to superoxide anion and hydroxyl radicals is comparable to another control group,and the DPPH free radical scavenging ability is slightly lower another control group.According to the result of the peroxide value of oil experiment,flavonoids from South Africa can decrease the peroxide value of animal and vegetable oils as 15.12%and 18.75%,which shows it has the ability to scavenge hydroxyl radicals.