Study On The Chemical Constituents And Antioxidant Activity Of Rhodiola Wallichiana

Rhodiola Wallichiana（Hook.）S.H.Fu var.cholaensis（Praeger）S.H.Fu is a plant of the genus Rhodiola in the Crassulaceae family.It has the effects of lowering blood sugar,anti-oxidation,anti-fatigue,and anti-radiation.It is clinically used to treat cardiovascular and cerebrovascular diseases.In order to further clarify the medicinal material basis of Rhodiola Wallichiana,the chemical composition and biological activity in Rhodiola Wallichiana were studied in this paper.Firstly,in this paper,70% ethanol was used as solvent to heat and reflux for extraction,and then column chromatography,preparative high performance liquid chromatography and other means were used to separate each chemical composition.Nine monomers（compound 1～9）were purified from the roots of Rhodiola Wallichiana.Secondly,by NMR,MS and other spectroscopy methods combing with physical and chemical properties analysis,9 compounds were elucidated as hexacosanol（1）,tetracosanol（2）,β-sitosterol（3）,kaempferol（4）,daucosterol（5）,rhodiolin（6）,herbacetin 7-O-α-L-rhamnopyranoside（7）,crenulatin（8）and salidroside（9）respectively.Among them,compound 1,2,4,6 and 8 were obtained from Rhodiola Wallichiana for the first time.Based on the study of chemical components,this paper established two different HPLC analysis methods for the first time to determine the two newly isolated chemical components and salidroside in Rhodiola Wallichiana.Firstly,the XDB-C18 column and HPLC-UV method were used to determine the content of rhodiolin in Rhodiola Wallichiana and the methodology was investigated at the same time.The test results showed that the peak area of Rhodiola Wallichiana within the range of 0.193～19.280μg,and the injection volume showed a good linear relationship,R²=0.9998,and its detection limit was 2×10^-4μg.The RSDs of the precision,repeatability,stability and sample recovery rate of Rhodiola Wallichiana were less than 2.0%（n=6）,respectively,indicating that the established assay method has the advantages of good precision and high accuracy.The content determination results showed that the content range of rhodiolin in Rhodiola Wallichiana from different producing areas was 0.006～0.274 mg/g.Secondly,the contents of crenulatin and salidroside in Rhodiola Wallichiana were determined by using amide chromatography column combined with HPLC-ELSD method,and the methodology was investigated at the same time.The experimental results showed that crenulatin has a good linear relationship in the range of 1.997～49.930μg,R²=0.9993,and its detection limit is 0.3μg,while salidroside has a good linear relationship in the range of 1.998～49.950μg.R²=0.9991,the detection limit is 0.2μg;The RSDs of the precision,repeatability,stability and sample recovery rate of crenulatin and salidroside are all less than 2.0%（n=6）,indicating that the assay method established in the experiment has the advantages of good precision,high sensitivity and high accuracy.The contents determination results showed that the contents of crenulatin and salidroside in different producing areas of Rhodiola Wallichiana were 0～24.769mg/g and 14.057～40.507mg/g,respectively.Both of them are high-content and characteristic chemical components in Rhodiola Wallichiana medicinal material.These two compounds will be considered as indicative component to improve the quality standards of the medicinal materials by performing content determination.In order to clarify the anti-oxidant active substances in Rhodiola Wallichiana,the experiment of scavenging·DPPH free radicals was performed on the effects of extraction,polysaccharide,injection and some monomer compounds of Rhodiola Wallichiana.and then,their activities were compared.The experimental results show that Rhodiola Wallichiana polysaccharides,rhodiolin,Rhodiola Wallichiana water extracts and alcohol extracts have a strong effect of scavenging·DPPH free radicals.However,Rhodiola Wallichiana injection,crenulatin and salidroside have poor scavenging ability against·DPPH free radicals.To sum up,this article first obtained 5 compounds from Rhodiola Wallichiana,and established two new HPLC content determination method for rhodiolin,crenulatin and salidroside in Rhodiola Wallichiana.In addition,the antioxidant activities of extraction,polysaccharides and monomer compound from Rhodiola Wallichiana were also studied and compared.The research results of this paper provided a new scientific basis for the in-depth research and development of the effective substances of Rhodiola Wallichiana.