Studies On AChE Inhibitory Activity And Chemical Constituents Analysis Of Alkaloids From Four Xinjiang Plants

Alzheimer's disease?AD?is one of the diseases which seriously threaten the health and life of human being.At present,Acetylcholinesterase inhibitor?AChEI?is considered to be the most effective strategy for the treatment of AD.In recent years,many AChEIs of structure types of alkaloid have been isolated from natural plants by domestic and foreign scholars,and the AChEIs which have already been put on the market for the treatment of AD are almost alkaloids.Therefore,it is of great significance to study the active components of Acetylcholinesterase?AChE?from plant alkaloid extracts for the further development of new drugs to treat AD.However,the components of plant alkaloid extract is extremely complex,it is difficult for traditional methods to achieve efficient separation and analysis.In this paper,we use Xinjiang characteristic plants,Peganum harmala L.,Oxytropis glabra DC.,Swainsonia salsula?Pall.?DC.and Sophora alopecuroides L.,as our materials and study their AChE activities.The two dimensional combined method liquid chromatography-ion mobility spectrometry?HPLC-IMS?,which was successfully established in our laboratory,was first applied to the efficient separation of alkaloid compounds,aiming to screen out new AChEI from natural plant alkaloids and to provide a new method for the separation and analysis of alkaloids.The main contents and results are as follows:1.Studies on AChE inhibitory activity and chemical constituents analysis of alkaloids from Peganum harmala L..The AChE activity of total alkaloid extract,chloroform phase,ethyl acetate phase,n-butanol phase,alkaloid precipitation phase and water phase were studied by modified Ellman colorimetry.The results showed that the alkaloids in the other phases of P.harmala L.except the aqueous phase had high AChE inhibitory activity,and their IC₅₀ values were 0.049 mg/m L,0.035 mg/mL,0.075 mg/m L,0.099 mg/m L and 0.104 mg/mL,respectively.Three monomer compounds were isolated from the chloroform phase,and were identified by ¹H NMR and ¹³C NMR as vasicinone,peganine?vasicine?and harmaline.In addition,four phase extractions of P.harmala L.were analyzed by using X-Bridge HILIC column combine with the HPLC-IMS system,and under the mode of multiplexing correlation ion mobility spectrometry?CIMS?.Eventually,33,18,24 and 17 compounds were obtained by detection,and 11,10,9 and 6 compounds were identified by mass spectrometry from chloroform phase,ethyl acetate phase,n-butanol phase and alkaloid precipitation phase,respectively.2.Studies on AChE inhibitory activity and chemical constituents analysis of alkaloids from Oxytropis glabra DC.and Swainsonia salsula?Pall.?DC..The AChE inhibitory activity of 25 phase extracts from two species of plants,O.glabra DC.and S.salsula?Pall.?DC.,was studied in this chapter.Results showed that the chloroform extracts of both root and leaf of O.glabra DC.and the leaf of S.salsula?Pall.?DC.demonstrated higher AChE inhibitory activities over other extracts with the IC₅₀ values of0.67mg/mL,1.69 mg/m L and 0.17 mg/mL,respectively.Besides,kinetic studies showed the inhibition mechanism of chloroform extracts from leaf of these two plants were both mixed type reversible inhibition.Beyond that,the chloroform extracts from leaves of O.glabra DC.and S.salsula?Pall.?DC.were analyzed by using PCP RP C₁₈8 column combine with the HPLC-IMS system,and under the mode of multiplexing correlation ion mobility spectrometry?CIMS?,36 and 26 compounds were obtained by detection,respectively.3.Studies on AChE inhibitory activity and chemical constituents analysis of alkaloids from Sophora alopecuroides L..The AChE inhibition activity of total alkaloids extracted from the root,stem,leaf,testa and seed of S.alopecuroides L.and five alkaloid standards were studied.The results showed that the seed of S.alopecuroides L.and the standard sophocarpine had high AChE inhibitory activity,with the IC₅₀values of 0.716 mg/mL and 0.17 mg/mL.Besides,kinetic studies showed the inhibition mechanism of total alkaloids from seeds of S.alopecuroides L.was mixed type reversible inhibition.Beyond that,the total alkaloids extracted from the root,stem,leaf,testa and seed of S.alopecuroides L.were analyzed by using PCP RP C₁₈column combine with the HPLC-IMS system,and under the mode of multiplexing correlation ion mobility spectrometry?CIMS?.Eventually,47,25,46,43 and 34compounds were obtained by detection,respectively.Most importantly,we have achieved the quantitative analysis of the compounds by HPLC-IMS with the help of two standard compounds,cytisine and aloperine.The contents of cytisine in root,stem,leaf,testa and seed total alkaloids were 1.05%,2.01%,0.44%,0.72%and 2.33%,respectively.And the contents of aloperine in stem,leaf and testat total alkaloids were0.23%,2.14%and 0.05%,respectively.