Studies On The Chemical Constituents And Biological Activities From Polygala Lijiangensis

In our country,the resources of medicinal plants of Polygala are very rich.It's common to see their application in clinical or folk medicine.Polygala lijiangensis C.Y.Wu et S.K.Chen is a new species discovered in 1980s,which mainly grow in Lijiang,Yunnan Province.In order to explore the relationships between the constituents of P.lijiangensis and their pharmacological activities,and research the differences in chemical compositions between P.lijiangensis,P.sibirica L.var megalopha Fr.,and P.crotalarioides,as well as provide scientific basis for the development and utilization of P.lijiangensis,this paper studied the compounds of P.lijiangensis and their xanthine oxidase inhibitory activities,and determined the index components with xanthine oxidase inhibitory activity,which were obtained from P.lijiangensis,P.sibirica L.var megalopha Fr.and P.crotalarioides.Then a method for quantitative determination of the index components was established,which laid the foundation for the development of natural drugs with high efficiency and low toxicity for gout.Through silica gel,MCI-gel,Sephadex LH-20,HPLC and other separation materials and instruments,20 compounds have been isolated from the roots and stems of P.lijiangensis.On the basis of NMR and MS spectroscopic data analysis,the structures of 17 compounds have been elucidated as 1,7-dihydroxyxanthone?1?;6-hydroxy-l,7-dimethoxy-xanthone?2?;3,8-dihydroxy-1,2,4-trimethoxyxanthone?3?;1,3,6-trihydroxy-2,7,8-trimethoxyxanthone?4?;6,8-dihydroxy-1,2,3-trimethoxyxanthone?5?;1,7-dihydroxy-3,4-dimethoxyxanthone?6?;1,3-dihydroxy-2,5,6,7-tetramethoxyxanthone?7?;3,6-dihydroxy-1,2,7-trimethoxyxanthone?8?;1,7-dihydroxy-3,5,6-trimethoxyxanthone?9?;1,3,6-trihydroxy-2,7-dimethoxyxanthone?10?;1,3,6,8-tetrahydroxy-2,7-dimethoxyxanthone?11?;polygalin A?12?;3,5-dihydroxy-7,4?-dimethoxyflavone-3-O-?-D-glucopyranoside?13?;chondrillasterol?14?;3-O-[?E?-3,4,5-trimethoxycinnamoyl]-?-D-fructofuranosyl-?2?1?-?6-O-benzoyl?-?-D-glucopyranoside?15?;tenuifoliside C?16?;3,6?-disinapoyl sucrose?17?.Through the screening of xanthine oxidase inhibitory activity of compounds isolated from P.lijiangensis,two xanthones with significant xanthine oxidase inhibitory activity,which were 1,3,6-trihydroxy-2,7,8-trimethoxyxanthone?4?and 6,8-dihydroxy-1,2,3-trimethoxyxanthone?5?,were identified as the index components of P.lijiangensis,P.sibirica L.var megalopha Fr.and P.crotalarioides.Taking allopurinol(IC₅₀=3.47?M)as positive control,the IC₅₀ values of the two index components were measured,which were 23.02?M and 15.39?M,respectively.Then the HPLC-DAD method was set up for the simultaneous quantitative determination of the two index contents,by two factors of retention time and the UV absorption spectrum to identify xanthones.This method is more accurate and reliable,which can be applied to quality control of xanthones and varitety identification of Polygala.At the same time,another HPLC-DAD method was also established which can simultaneously determine the contents of three oligosaccharide esters from three species of Polygala:3-O-[?E?-3,4,5-trimethoxycinnamoyl]-?-D-fructofuranosyl-?2?1?-?6-O-benzoyl?-?-D-glucopyranoside?15?;tenuifoliside C?16?;3,6?-disinapoyl sucrose?17?.