Chemical Components And Biological Activity From The Resins Of Populus Euphratica

Objective:Tears of poplar,also known as tears of WuTong and euphratica,is the secretion from the dried branches of Populus euphratica in Salicaceae and used medicinally.Euphrates poplar is the oldest poplar species in the world which is mainly distributed in the south of Xinjiang Uygur Autonomous Region,west of qaidam basin,hexi corridor and other arid desert areas at lower elevations.It is a symbol of the great national spirit of Chinese people,which is indomitable and unyielding.The tang dynasty's"new pruning"records Tears of poplar,salty and bitter,cold,qingrejiedu,pain".It is mainly used for the treatment of sore throat,sore mouth and tongue,lymphatic tuberculosis and pain caused by stomach and duodenal ulcer.Literature research shows that there is little research on tears of poplar,and the chemical components that play the main role are not clear,also the unknown mechanism of pharmacodynamic substances.Moreover,it is not included in the pharmacopoeia,indicating that further research on tears of poplar is needed.Therefore,the research propose of our project is to find the effective ingredients or lead compounds for the creation of new drugs,so as to lay a foundation for the development of new drugs,the expansion of medicinal resources,the clarification of the properties and functions,and efficacy of tears,and the establishment of quality evaluation standards for tears.Methods:the total extract was obtained by grinding and extracting with 95%ethanol,diluted with water and then extracted with ethyl acetate for 3 times to obtain the ethyl acetate partition.Chromatography over silica gel,MCI gel CHP 20P,Sephadex LH-20,RP-18,semi-preparative HPLC combined with Preparative thin layer chromatography?PTLC?and recrystallization were applied to afford monomer compound.Their structures inclusive of absolute configuration were established based on Spectral data(¹H-NMR,¹³C-NMR,HSQC,HMBC,¹H-¹H COSY,ROESY,NOE irradiation,UV,MS,etc.),chemical reaction method and ECD calculation method.Some compounds were selected to evaluate for neuroprotective activities via CCK-8and one-way ANOVA with post-hoc comparison Turkey statistical method.Results:33 compounds were isolated from the resins of Populus euphratica,of which 20 were new compounds.These compounds were mainly pentacyclic triterpenoids,nortriterpenoids,cambrane-taye diterpenoids,abietane-type diterpenoids,verticillane-diterpenoids,sesquiterpenoids and monoterpenoids.Compounds 5,6 and 8can significantly inhibit the oxidative stress caused by H₂O₂,compounds 7-8,11-12,14,16 and 33 can significantly inhibit the excitatory toxicity caused by glutamic acid,and show concentration dependence.Conclusions:The neuroprotective constituents isolated from the resins of Populus euphraticamostly possess?,?-unsaturated ketone moieties which implies?,?-unsaturated ketones may play the vital role in maintaining neural protection.Other compounds isolated also provide scientific basis and reference for further pharmacological research and elucidating the material basis for the traditional effect of tears of poplar.