Sectional Study On The Chemical Constituents Of Some Extracts From Licorice Root And Analysis Of Their Antioxidant Activity

The aerial part of licorice is rich in flavonoids which has good anti-tumor,anti-inflammatory effects,so the study of the pharmacological activity of the aerial part of licorice are of great significance to expand drug source and make full use of licorice resources.However,due to interference in numbers of other non-activity in the aerial parts of licorice,the content of flavonoids in the licorice extract are low,the efficiency are weak,which severely restricts the further use of flavonoids in aerial part of licorice.Thus,enrichlent and purification of flavonoids is the basis for development and utilization of the aerial parts of licorice.Material in aerial parts of licorice are varied and has complex composition,and there are great difference of antioxidant activity between different material,so evaluation of the antioxidant activity of material is very necessary for further utilization of resources.Based on this,the study optimizes a process of enrichment of flavonoids by macroporous resin column chromatography,and studies the segmentation of chemical components by combining the use of solvent extraction method and column chromatography.This study also evaluates the antioxidant activity of each component and lay the foundation for further development of licorice aerial part.The results are as follows:(1)Establishment of aerial part licorice flavonoids content determination methodThe study establishes a proper content determination method for total flavonoids in aerial part of licorice by UV-visible spectrophotometry,combines seven kinds of assessment methods with the direct assay,AIC13 colorimetric method,10%KOH chromogenic method and NaNO2-Al(NO3)3-NaOH colorimetric method,with liquiritin,rutin and quercetin as control.Compare and study the precision,stability,linearity and recovery rate of the seven methods,choose the appropriate portion of the total flavonoids determination methods in aerial part of licorice,The final content determination method of total flavonoids in aerial part of Licorice is the method of which,10%KOH determination as chromogenic agent,quercetin as control.Steps are as follows:Precise amount of the sample solution(2mL)was put into 10mL volumetric flask,1mL 10%KOH solution was added,shake well and let stand for 5 min,deionized water was added to the mark,and mix well before determination using ultraciolet absorption.(2)Screening of the macroporous resin process for flavonoids enrichment in aerial part of licoriceRecovery rate of total flavonoids as indicators to screening macroporous resin model and optimize the enrichment and purification parameters,developing a suitable process of enrichment and purification of the total flavonoids in aerial part of licorice.Screening resin models through static and dynamic adsorption and desorption,four factors of the sample concentration,the sample solution pH,the sample rate and the concentration of ethanol elution were optimized by orthogonal design(L,6(45)).The results showed that HPD-BJQH macroporous resin was best suited for enrichment of total flavonoids in aerial part of licorice;optimal process:the sample concentration was 2.15 mg.mL-1,the sample volume was 9 BV,the sample solution was pH 5,the sample rate of 3 BV/h5 70%ethanol elution rate of 2 BV/h,the elution volume of 3 BV.Total flavonoids purity upgraded from the original purity of 13.39%to 44.92%after purification.It was proved that the results of the process was stable and could purify flavonoids in aerial parts of licorice preferable.(3)Segment of total fnavonoids in aerial part of licorice into five components according to the chemical composition characteristicsEstablished the HPLC-UV fingerprint of aerial part of licorice supernatant,and use this fingerprint for fraction research of total flavonoids in aerial part of licorice.Yield of total flavonoids and the difference between total flavonoids chemical compositions were indicators for fractionation.Supernatant was fractionated by macroporous resin,three fractions were got,fraction eluted with 30%,50%and 70%ethanol parts.Precipitation was fractionated using solvent extraction into ethyl acetate fraction and chloroform fraction.Chemical composition and flavonoid content are quite different in the five components.(4)The chloroform fraction has the best antioxidant activity and can be studied for further development and utilizationCompared the antioxidant activity of the supernatant,precipitation,total flavonoids and the five sub-components,with ascorbic acid and rutin as positive control.The chloroform fraction showed the best antioxidant activity while the supernatant fraction showed the worst.Antioxidant activity of fractions of 30%ethanol,50%ethanol and 70%ethanol showed increased activity of antioxidant in the order,chloroform fraction showed better activity than the ethyl acetate fraction,the antioxidant activity and polar of substances showed the opposite trend.Further development and utilization can be focused on chloroform fraction.