Chemical Transformation Of Ginsenosides And Its Protective Effects And Structure-activity Relationship On Damaged Nerve Cells Induced By H₂O₂

Ginseng (Panax ginseng C.A.Meyer) has a long medicinal history in China foritswidely efficacy. Ancient Chinese medical books recorded it could supplement the mainorgans, spirit, set soul, check fright, decrease evil, improve eyesight happy puzzle, longtake intellectual man fit live”, and these efficacy has been gradually explained by themodern pharmacology. Ginsenosides are the main active ingredients of ginseng, which canalmost reproduce all of the pharmacologically activity of crude ginseng preparation.Ginsenosides have rich structure, which provides the material basis for its extensivepharmacological activities. Ginsenosides includes not only the directly isolatedginsenosides from ginseng as Re, Rb1, Rd, also include the secondary saponinginsenosides in vivo and in vitro metabolism. Ginsenosides possess variouspharmacological activites with the different structures, which laid the foundation for thestudy about structure-activity relationships of ginsenosides. Numerous studies have shownthat ginsenosides can regulate the central nervous system, anti-oxidation, anti-aging, andso on.In this study, we used ginseng saponin, panax notoginseng saponins andpanaxleaves glycosides as experimental materials to obtain the transformated saponon byusing high temperature and high pressure alkaline degradation, acetic acid degradation,sulfuric acid degradation. The separation and purification of the degradation major usedmulti-step silica gel chromatography method. And the structures of monomer compoundswere confirmed by NMR techniques. Orthogonal experiments were designed to optimizethe process of the preparation of ginseng saponin20(S)-protopanaxadiol,20(S)-protopanaxatriol,20(S)-Rh2and process20(S)-Rg3. In addition, the protectiveeffect of ginsengosies on SH-SY5Y cells and C6cells were measured, which wereoxidative injured by hydrogen peroxide (H2O2), an exogenous free radical. Thestructure-activity relationships were further evaluated in this study. The results willcontribute to the development of ginseng drugs for neurological diseases, as well as thetreatment of certain diseases of the nervous decency. The main findings are as follows: (1) Radix notoginseng were converted to degradation product by alkaline in250℃30minutes. Five compounds were confirmed as20(S)-protopanaxadiol,20(S)-protopanaxatriol,(20S,24R)-Ocotillol,20(S)-panaxadiol,20(S)-Panaxatriol.(20S,24R)-Ocotillol was first discovered in alkaline degradation products from radix not-oginseng.(2) Two compound were derived from radix notoginseng by alkaline degradation in210℃for2hours. Silica gel column chromatography were used and ethyl acetate:methanol (8:2), dichloromethane: methanol (7:1.1), chloroform: methanol: water (7:3:0.5)as solvent system. The two compounds were confirmed as20(S)-ginsenoside Rh2,20(S)-ginsenoside Rg3.(3)20(R)-ginsenoside Rh2and20(R)-ginsenoside Rg3were got by silica gel columnchromatography from acetic acid degradation of Notoginseng glycosides.(4) Using20(S)-protopanaxadiol,20(S)-protopanaxatriol as raw materials. We gettwo compounds by silica gel column chromatography from sulfuric acid degradation.They were confirmed as20(R)-protopanaxatriol,20(R)-protopanaxatriol and20(R)-panaxadiol,20(R)-Panaxatriol.(5) Notoginseng leaf glycosides were converted to degradation product byhydrochloric acid hydrolysis degradation.We get20(R)-Panaxadiol and20(R)-protopanaxadiol by silica gel column chromatography, and the structure ofcompounds14and15have not been confirmed by NMR.(6) The process for preparing ginseng saponin20(S)-protopanaxadiol,20(S)-protopanaxatriol,20(S)-Rh2and20(S)-Rg3simultaneously were optimized by anorthogonal experimental design, and the process is: Under certain amount of glycerolconditions, the concentration of saponin was10%, NaOH concentration was15%, thereaction temperature was230℃, the reaction time was2.5h.(7) We established a model of H2O2damage SH-SY5Y cells and C6cells. For C6cells, the concentration H2O2is700μmol/L, incubation time is4h, for SH-SY5Y cells, theconcentration H2O2is600μmol/L, incubation time is4h, and the damaged rate of cellsunder the experimental conditions is30%.(8) We used MTT to assay the effect of different ginsenosides treatment to theviability of SH-SY5Y cells and C6cells damaged by H2O2. We also assayed the release of LDH. Compared with model group, ginsenoside Rb1, Re, Rg1, R-Rg3, R-Rh2cansignificantly improve the viability of C6cells and SH-SY5Y cell damaged by H2O2, andreduce the release of LDH. Ginsenoside R-PPD, R-PPT, low concentrations of S-Rg3,S-Rh2, R-PD, R-PT can improve the viability of C6cells and SH-SY5Y cells damaged byH2O2and reduce the release of LDH. S-PPD, S-PPT, S-PD, S-PT can not significantlyimprove the viability of C6cells and SH-SY5Y cell damaged by H2O2and reduce therelease of LDH.(9) The effect of ginsenosides on MDA and SOD from SH-SY5Y cells H2O2injuredis as follows: These ginsenosides can significantly decrease the levels of MDA, andincreased levels of SOD in cells.(10) The structure-activity relationship of these ginsenosides to protective agains-tH2O2injury in SH-SY5Y and C6cells were evaluated. The directly isolated ginsenosidesfrom ginseng such as ginsenosides Rb1, Re, Rg1have significant protective effect toSH-SY5Y cells and C6cells injured by H2O2. The protective effect of ginsenosides withR-type in C20is stronger than the S-type ginsenosides. The protective effect of theprotopanaxadiol type ginsenosides is stronger than protopanaxatriol type ginsenosides.The protective effect of non-ring side chain ginsenosides is stronger than ring side chainginsenosides. With the reduction of sugar chains, the protective effect of ginsenosidesbecomes weaker and weaker.