Study On L-Arg And Arginine Derivatives Of Panax Quinquefolium L.

Similarity of chemical composition is an important guide to the study on botanic chemical constituent in identical family plant.American ginseng produced in American is in the same family and genus as ginseng. However.Reserch on chemical and pharmacologic action of American ginseng can't compare with that of ginseng deeply.For the purpose of researching on nonsaponins of American ginseng and exploiting anti-oxidant and antidotal medicine.we carried out the extraction,isolation and quantitative analysis for L-Arg and arginine derivatives(AF,AFG) which will make a deep foundation for investigating Maillard reaction mechanism in plant.A reversed phase high performance liquid chromatographic method for simultaneous determination of 17 free amino acids in Panax quinquefolium L.was utilized.The amino acid samples were mixed with norleucine as the internal standard,derivatized with Phenylisothiocyanate(PITC),and then separated on a Venusil-AA (5μm,4.6mm×250mm) column used specially for analysis amino acid using NaAC buffer solution(pH6.5)-acetonitrile solution and 80%acetonitrile solution as a mobile phase with gradient elution technique.Flow rate:1mL/min,column temperature:40℃,The UV detector at 254nm was utilized for amino acid quantification.All 17 amino acids concentration was set at the range of 0.5μmol～0.0125μmol,the linear correlation coefficients of the amino acids were above 0.99.The average recoveries of amino acids were 96.5%～102.3%.This technique was simple,accurate,suitable for quatitative analysis of amino acid of American ginseng.The result indicated that arginine was the major free amino acid and constituted over 50% of all the free amino acids detected in the root.Because sufficient free arginine is the foundation of the generation of arginine derivatives.The result provided the precondition for intensifying the study on arginine derivatives in Panax quinquefolium L.On the basis of forward work,the experiment adopted the new segregation system including organic solvent extraction,macroporous adsorptive resins chromatography,Sephadex LH-20 chromatography, column chromatography and silica gel chromatography,and separated L-Arg,AF and AFG.It consummated the chemical composition of American ginseng.The method with the common packing material,simple procedure,short time,provided reference for purification of Maillard reaction product.The experiment established a reversed phase high performance liquid chromatographic method for simultaneous determination of AF and AFG in Panax quinquefolium L.The experiment determined and compared with the contents of AF,AFG in different part of fresh plant and dried radix of American ginseng. The result indicated that both AF and AFG existed in dried radix,fresh radix and fresh fruit of American ginseng,and the content of AF in plant was higher than that of AFG.The experiment optimized synthesis technology through design by uniform distribution and statistical analysis software.The result indicated the transformation efficiency reached 50%in the best technology.And it was possible to large-scale preparation of AF by silica gel chromatography,70%ethanol isocratic elution.Using the assay system of DPPH,OH and O₂^-·.The antioxidant activities of L-Arg and arginine derivatives were studied.The results showed that L-Arg,AF,AFG and their total synthetics had scavenging effects on free radical.and the AF and its total synthetics were better than others.Besides,the inhibition effects of the total synthetics on lipoprotein oxidation in calf serum exposed to Cu²⁺ were assessed.The results showed the total synthetics exhibited inhibition effects on calf serum lipoprotein oxidation in a dose-dependent manner.The results made a deep foundation for knowing the biology activity deeply and developing the antiaging agent further.