Study On Antioxidant Compounds Of Tibetan Medicine Dali

Tibetan medicine Dali belongs to the Ericaceae family:which is also named Peru and little azalea. Dali, the dry flowers and leaves of Rhododendron anthopogonoides Maxim. R. cephalanthum Franch. and R. primulaeflorum Bur. et Franch., is used in Tibetan medicine for the treatment of Long diseases, Chiba diseases and Peigen diseases, which treats chronic bronchitis and High Altitude Polycythemia (HAPC). HAPC is frequently encountered in the plateaus of China, which is caused by metabolic imbalances of free radicals imposed by plateau hypoxia and series of pathological changes whereby from oxidative stress induces apoptosis in modern studies. However, there is no reports on Dali for the treatment of HAPC though anti-oxidant.ObjectiveIdentify and separate the antioxidant components of Tibetan medicine Dali, which is mainly base on R. primulaeflorum Bur. et Franch.Methods1. To preliminarily screen Dali's antioxdant components by DPPH with Vc as a positive comparative. To analysis and compare antioxdant components of different medicinal parts and polarity solvent extracts of Dali combined with the method of TLC-bioautography.2. To study on the chemical components of ethyl acetate extracts, which have stronger oxidation resistance, by the means of phytochemistry, including silica gel column chromatography, sephadex column chromatography, etc.3. To preliminarily establish the fingerprints of Dali by HPLC, and primarily analysis the compounds in the serums of rats after administration Dali by serum pharmacochemistry.Results1.All medicinal parts of Tibetan medicine Dali had antioxdant components, and flowers and leaves had weaker antioxdant resistance. The antioxidative activities of different polarity solvent extracts were ethyl acetate extracts> n-butyl alcohol extracts> water extracts, and ethyl acetate extracts were the most strong among them.2. Six compounds of ethyl acetate extracts of Dali (β-sitosterol (compound I), Hyperoside (compoundⅡ), Quercetin (compoundⅢ),7-Hydroxycoumarin (compoundⅣ), Quercitrin (compound V), Quercetin-3-O-a-L-rhamnopyranoside (compoundVI)) have been isolated and purified as reference substance for chemical analysis and screening for the active ingredients. Compound IV, compound V, compoundⅥwere first isolated from Dali.3. The chromatographic fingerprints of the different samples have been analyzed and investigated by HPLC, in which 5 major chemical components, such as 7-Hydroxycoumarin, Hyperoside, Quercitrin, Quercetin-3-O-a-L-rhamnopyranoside and Quercetin were identified by the retention times, which showed tha the chemical ingredients between flowers and leaves were different. Hyperoside as the prototype constituent absorbed in blood was determined by the method of serum pharmacochemistry, and the other two components might be the metabolites.Conclusion1. The methods of DPPH-Spectrophotometer and TLC-bioautography could rapidly choose antioxidative components of Dali, which were accurate and reliable to distinguish active and non-active compounds.2. The major antioxidant components of Dali were flavonoids in which Hyperoside might be one of the antioxidant components in vivo.