Study On The Improvement Effect Of Nymphaea Hybrid Extract On Learning And Memory Ability Of Alzheimer's Disease

The prevention and treatment of Alzheimer's disease(AD)is a major difficulty in current research.Its pathogenesis is complex,and the current research is mainly aimed at improving memory impairment in patients,from free radical damage,cholinergic damage,A? neurotoxicity,tau phosphorylation,and neuroinflammation.Studies have shown that phenolic compounds can interfere with multiple pathogenesis of AD.Nymphaea hybridis a water-borne herb of the Nymphaeaceae family with the genus of Nymphaea.It has a variety of biological activities and its efficacy is closely related to the rich phenolic compounds.In this paper,Nymphaea hybrid extract(NHE),which had a good inhibitory effect on acetylcholinesterase(AChE)activity,was prepared by using the blue Nymphaea hybrid as raw material and AChE activity inhibition rate as index,and explored its influence on the ability of learning and memory in mice and the possible mechanism of action by scopolamine-induced memory impairment mice.The results of this paper were as follows:(1)In vitro AChE inhibition experiments showed that the inhibitory effect of NHE on AChE was dose-effect,IC50 was 239.34±4.24 ?g/mL,and the inhibition type was mixed reversible inhibition.The preliminary purification of NHE by a fractional extraction method had certain effects.The phenolic compound was enriched in the ethyl acetate phase,and the IC50 of the ethyl acetate phase was 184.62±2.52 ?g/mL,which was superior to NHE.At the same time,Pearson correlation analysis found that the inhibition rate of AChE activity of NHE and its fractionation phase was significantly correlated with total phenolic content and total flavonoid content(r>0.8).(2)UPLC-Triple TOF-MS/MS technology was used for the first time to comprehensively analyze phenolic compounds in NHE.Twenty-two phenolic compounds were identified in NHE,including seven phenolic compounds and fifteen flavonoids.Quantitative analysis of eight phenolic compounds in NHE showed that their content in NHE was low,and the highest content of Corilagin was 2.63%.However,the inhibitory effect of NHE and ethyl acetate phases on AChE was the result of the interaction of various compounds.Among them,gallic acid,quercetin,ellagic acid,myricetin and quercetin had lower IC50 values for AChE activity than NHE and ethyl acetate phases,and they were presumed to be important compounds.(3)Using the scopolamine-induced memory impairment mouse model,Morris water maze test results showed that NHE could reverse the learning and memory defects caused by scopolamine in mice,and showed a dose effect,which was shown in the following:the escape latency was significantly shortened(P<0.01),crossing platform times and the percentage of target quadrant residence time increased significantly(P<0.05),and the swimming pattern of the mice was improved.At the same time,the pathological results of mouse brain showed that NHE could ameliorate the abnormal changes of mouse brain tissue caused by scopolamine,increase the number of neurons,and reduce the cells in the solidified atrophic state,so that the cell arrangement tended to be tight.(4)Elisa kit and Western blot analysis showed that NHE intervention reversed brain oxidative stress induced by scopolamine,decreased MDA content(P<0.01),increased SOD and GSH-Px activity(P<0.01);NHE intervention could restore cholinergic damage caused by scopolamine,increase ACh content in hippocampus and cortex of mice(P<0.01),and decrease AChE activity(P<0.01);NHE intervention could reduce synaptic plasticity injury caused by scopolamine,increase the phosphorylation level of extracellular signal-regulated protein kinase(ERK)and cyclic adenosine response element binding protein(CREB)in hippocampus and cortex of the brain(P<0.01),while increasing brain-derived neurotrophic factor(BDNF)expression.In conclusion,the results of NHE's in vitro inhibition of AChE experiments and in vivo scopolamine-induced memory impairment AD mouse model had shown that NHE had the potential to prevent AD,including:improving brain oxidative stress,balancing cholinergic system,and activating ERK-CREB-BDNF signaling,and its role was closely related to phenolic compounds,which may be the result of the interaction of multiple phenolic compounds.This paper provided a theoretical basis for the development and utilization of perfume lotus extract to improve memory and prevent Alzheimer's disease.In conclusion,the results of in vitro inhibition of AChE activity assay and in vivo scopolamine-induced memory impairment in a mouse model suggest that NHE has the potential to prevent AD,and the specific mechanism involves:improving brain oxidative stress,balancing cholinergic system,and activating ERK-CREB-BDNF signaling pathway,and its role is closely related to phenolic compounds,may be the result of a combination of multiple phenolic compounds.This paper provides a theoretical basis for the development and utilization of NHE to improve memory and prevent Alzheimer's disease.