Study On The Effective Components Of Radix Astragalus

Radix Astragalus,usually used as a traditional Chinesemedicine,has many effects of replenishing "qi",depressing bloodpressure, stimulating heart,diminishing inflammation,promotingthe subsidence of swelling,reinforcing immunity and so on. RadixAstragalus is the radix of Astragalus membranacens Bunge andA.membranacens var.mongolicus(bunge)Hsiao.The main efficiencycomponents from Astragalus are Astragalus saponins and Astragaluspolysaccharides.There are many studies about the optimum condition of thetraditional ethanol extraction in recent years.These methodsimprove the efficiency comparatively, but the result is notperfect.In this research,we studied the ethanol-alkali extractionmethod of astragalus polysacchar ides and astragalus saponins,thenstudied isolation, purification and activity of the extraction.Atthe same time , we studied the effect of solvents on the cell walltissues in the extraction process of astragalus polysaccharidesfrom efficiency components of astragalus by the histochemical ways.At first,we applied the ethanol-alkali extraction method toextract astragalus polysaccharides.The optimum extractioncondition was identified by single factor investigation,the extr-action condition was as follow: pH of extraction solvent was 12,the ratio of material to extraction solvent was 1:10,extractiontime was 90min,extraction temperature was 90 ℃ ,ethanolconcentration of extraction solvent was 5%,extracting 2 times.Theresults showed that the extraction rate of ethanol-alkali extract-ion method is 19.15%,it is 3.53 times as much as water extractionrate and 2.63 multiple of alkali extraction method.Thepolysaccharides extracted by ethanol-alkali solvent wasdeproteinised by TCA, dialysed , chromatographed on DEAE-cellulosecolumn and purified by Sepherdex G25 column. The three types ofelements which were labeled P31,P32 and P33 were obtained.Theelements were proved to be single components by freezing-thawingexperiments and paper chromatography. The scavenging rate ofP31,P32 and P33 for superoxide radical and hydroxyl radical weredetermined,compared with P11,P12 and P13 which were extracted bywater extraction method and P21,P22 and P23 by alkali extractionmethod. It is found that the scavenging rate of P11,P21 and P31 forhydroxyl radical were 89%,87% and 88%,that of P12 ,P22 and P32 were57%,48% and 53% as well as that of P13,P23 and P33 were 45%,23 %and 33%. The hydroxyl radical scavenging ability of polysaccharidesextracted by ethanol-alkali method were 1%,4% and 12% less than thatby water method as well as 1%,5% and 10 %higher than that by alkaliextraction method. The scavenging rates of P11,P21 and P31 forsuperoxide radical were 12%,8% and 11%, that of P12,P22 and P32 were23%,16% and 20% as well as that of P13,P23 and P33 were 37%,24% and34%. The superoxide radical scavenging ability of polysaccharidesextracted by ethanol-alkali method were 1%,5% and 3% less than thatby water method as well as 3%,4% and 10% higher than that by alkaliextraction method.It is proved that the scavenging ability ofhydroxyl radical and superoxide radical for the polysaccharideextracted by ethanol-alkali solvent is near to that extracted bywater extraction method.Secondly,the ethanol-alkali solvent was used to extract thesaponin in astragalus.The optimum extraction condition isidentified by the uniform design experiments.The extraction rateof saponin extracted by ethanol-alkali solvent which reached 2.62%was 1.04 times as much as that extracted by 95% ethanol which isreported to be a highest way and 1.53 times as much as that by 70%ethanol in soxhlet which is an often used way.The crude saponin wasprepared by 1-butanol and chromatographed on macroporus resincolumn and silicagel column. At last,three types of elements whichwere labeled S31,S32 and S33 were obtained and were identified tobe purities by TLC.The scavenging rate of S31, S32 and S33 forsuperoxide radical and hydroxyl radical were determined ,comparedwith that of S11,S12 and S13 which were extracted by soxhlet way.Itis found that the scavenging rate of S11,S12 and S13 for hydroxylradical were 55.42%,19.87% and 25.3%,as well as that of S31,S32and S33 were 61.4 % ,27.1 % and23.4 % .The hydroxyl radicalscavenging ability of S31 and S32 were 5.09% and 1.8% higher thanthat of S11 and S12. The hydroxyl radical scavenging ability of S33is 1.9% less than that of S13. The scavenging rate of S11,S12 andS13 for superoxide radical were 12.65%,6.9%and 27.1% as well asthat of S31,S32 and S33 were 12.65 % ,8.9 % and 15.82 % .Thescavenging rate of S31 was as same as S11,S32 was 2.0% higher thanS12,S33 was 11.28% less than S13.It is indicated that the saponinsextracted by ethanol-alkali solvent has the scavenging ability ofhydroxyl radical and superoxide radical.It was discovered that the effect for cell wall using differentextraction solvents by the histochemical ways,such as the swellingratio,paraffin section,IR spectrum and analyzing cell wallcomponents.It is showed that the ethanol-alkali solvent canincrease the swelling ratio as well as the swelling speed.The cellextracted by ethanol-alkali solvent becomes so loose showed by thewax section results,it is in favor of extraction.Analysising theIR spectrum and the results of measuring the cell wall components,itwas found that the ethanol-alkali solvent can decrease the pectinin the wall to make the wall broken,so that the components can beextracted easily by the solvent and the extraction rate wasincreased.In conclusion,it is resulted that the ethnaol-alkali extractioncan get higher extraction rate than the reported ways for the mainefficiency compents in the Chinese tradition medicine such assaponin and polysaccharide. Especially,it can increase theextraction rate for polysaccharide clearly.It will be useful in awide variety of applications for extraction of the efficiencycomponents.