Study On The Pharmacodynamic Material Basis And Mechanism Of Ding-Zhi-Xiao-Wan Prescription In The Treatment Of Alzheimer's Disease Based On PK-PD Correlation Analysis

Herb compatibility,as the basic characteristic of traditional Chinese medicine(TCM),is of great importance in the study of TCM modernization.In TCM theory,compatibility refers to the combination of two or more herbs based on the clinical settings and the properties of them,which helps enhance the therapeutic effects and counteracts the toxicities or side effects.There seems to be a general assumption that the synergistic therapeutic effects of TCM derive from the complex interactions between the multiple bioactive components within the herbs and/or herbal formulations.The biological process of TCM compound is essentially the interaction of "intervention system(TCM compound)-response system(biological organism)".On the one hand,absorption,metabolism,distribution and excretion(ADME)occur in the TCM formula under the influence of biological organisms.PK study is a significant method to clarify the rule of ADME of TCM formula.On the other hand,the organism is affected by the TCM formula to produce a medicinal or toxic effect.Endogenous metabolite group will make response after biological organism affected by TCM formula.Based on metabolomics strategies,the study of the most downstream endogenous metabolites of gene and protein functional activities can characterize the response of the organism's overall functional state under the action of TCM formula.More and more studies have used biomarkers of metabolomics as the study indexes of pharmacodynamics(PD).The PK-PD correlation analysis can focus on intracorporal process of drug,drug overall effect,and the relationship between them.The combination of two systems contributes to the comprehensive and systematic solution of scientific questions such as the pharmacodynamic material basis and action.mechanism of TCM formula.Ding-Zhi-Xiao-Wan(DZXW)was originally recorded in "Bei Ji Qian Jin Yao Fang" written by Sun Simiao.The formula has multiple bio-activities in TCM,especially in insomnia,depression and Alzheimer's disease(AD).AD is a multi-factorial disease characterized by loss of cholinergic neurons,extracellular deposition of ?-amyloid(A?)protein,intracellular neurofibrillary tangles(NFT)formation,neuroinflammation,oxidative stress and neurotransmitter deficit.With the continuous development of analytical techniques,more and more studies have shown that DZXW can treat AD through multiple channels and targets.Therefore,this paper establishes a series of analysis methods to clarify pharmacodynamic substance basis and mechanism of DZXW in the treatment of Alzheimer's disease through PK-PD correlation analysis.1 We developed a novel putative multiple-reaction monitor(PMRM)strategy based on ultra-high liquid chromatography tandem mass spectrometry(UPLC-MS)to broaden the coverage of quantification.The strategy was successfully used for the comparative PK study after the oral administration of DZXW and its single herbs.Ginsenoside,polygala saponins,xanthones,oligosaccharide esters,and tetracyclic triterpene were selected as PK markers.The mean plasma concentration-time curves and the PK parameters of these active ingredients in DZXW and its single herbs were used to determine possible herb-herb interactions.The visualized quantitative results showed that the PK behaviors have been significantly changed.Moreover,the compatibility could increase the bioavailability and eliminate possibly toxic effect,which reflects the rationality of TCM.2 APP/PS1 mice could model most facets of human AD,and have been extensively characterized and utilized in the pathological study of AD.The action mechanism and compatibility mechanism of DZXW in the treatment of AD were studied from the cognitive functions,A? protein deposition,tau protein hyperphosphorylation,oxidative stress and neuroinflammation by using APP/PS1 mice model.The result revealed that ginseng and poria cocos played the key roles in the aspects of improving learning and memory ability,cholinergic damage,neuroinflammation and reducing A? deposition,tau hyperphosphorylation.The synergistic effect of Polygala Radix and Acori Tatarinowii Rhizoma mainly promoted the therapeutic effect of the two herbs.3 In this study,longitudinal metabonomics(7,8,and 9 months)of feces were used to study the protective effect of DZXW on APP/PS1 mice combined with pathological studies and targeted metabolomics.After DZXW administration,A?deposition was significantly reduced,synaptic density was increased,and pathological features such as inflammation were improved.24 potential biomarkers in feces were identified which were relevant to the therapeutic effect of the DZXW on APP/PS1 mice.Those metabolites were mainly involved in bile acid and fatty acid metabolism.Metabolomics studies have shown that DZXW played a role in inhibiting inflammatory response by regulating the levels of endogenous metabolites in related pathways.4 Recent studies have indicated that altered gut microbiota is involved in neurodegenerative disease including AD.These mutual effects may be regulated partly through the metabolome,especially bile acids(BAs).Triterpene acids,including pachymic acid and poricoic acid B,are the major active compounds of Poria cocos in the treatment of AD,and most of the active ingredients are distributed in the feces and blood.The active ingredients distributed in feces may become potential substrates for gut microbiota.In this study,behavioral,immunohistochemical(IHC),and 16S rRNA sequencing experiments were conducted to evaluate the multi-target therapeutic effect of PC.In addition,a targeted metabolomics approach was also used to investigate BA profiles and to further verify whether PC could improve the pathological conditions by regulating the brain-gut-microbiota axis and the multi-target synergistic regulation network.After PC treatment,A? deposition was reduced by inhibiting ?-secretase and y-secretase and increasing A? phagocytosis and clearance.PC might regulate probiotic bacteria and restrain pathogenic bacteria simultaneously in the gut microbiota,which reversed the dysfunction of metabolites such as BAs.In conclusion,PC with multiple components plays a remarkable role in the treatment of multifactorial diseases such as AD.5 In the present study,we used triple-probe microdialysis combined with liquid chromatography coupled to a triple quadrupole tandem mass spectrometer(MD-UPLC-QQQ-M S)to directly collect and quantify the exogenous active compounds and endogenous neuroactive substances in the hippocampus,blood and kidney tissue of AD rats.The visualized method was established to express the relationship between pharmacokinetics and pharmacodynamics of DZXW in the treatment of AD.Results indicated that the relationship between the PK indexes and PD indexes was not a simple linear correlation,but a complex correlation and the delayed effect of PK indexes.The change trends of metabolites in the hippocampus tissues and blood were highly synchronized.Ginsenosides,including PK3(Re),PK4(Rf),and tetracyclic triterpenes,including PK5(DDTA),PK6(PAB),presented similar mechanisms of regulating the PD indexes.In comparison,the PK indexes of xanthones(PK1,PIII)and oligosaccharide esters(PK2,SA6)may employ the other mechanism.These results provide a new perspective for elucidating the active substances of DZXW and their mechanism of treating AD.