OBJECTIVE: To analyze the brain-absorption components of Liuwei Dihuang pills by applying ultra performance liquid chromatography-quadrupole rod-time of flight-mass spectrometry（UPLC-Q-TOF-MS） technique

and to explore the core targets

key pathways and other potential mechanisms of these components in improving learning and memory abilities of D-galactose（D-gal） model rats based on network pharmacology and extracorporal validation experiments. METHODS: The model was constructed by subcutaneous injection of D-galactose 250 mg/（kg·d）. The experiments were divided into the blank group

model group and administration group [Liuwei Dihuang pills

1.62 g/（kg·d）]. The learning and memory abilities of rats in each group were evaluated by two behavioral experiments including new object recognition and Morris water maze; the morphology of hippocampal neurons in each group was observed by hematoxylin-eosin（HE） staining; fast recognition and identification of chemical components were conducted on the cerebrospinal fluid samples of blank rats and rats treated with Liuwei Dihuang pills by UPLC-Q-TOF-MS technique

so as to determine the prototype brain-absorption components of Liuwei Dihuang pills. The potential effect targets of the brain-absorption components of Liuwei Dihuang pills were predicted through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and Swiss Target Prediction database

the Alzheimer’s disease（AD）-related disease targets were screened through the therapeutic target database and GeneCards databases

the intersection of drug component targets and disease targets was taken to draw the Venn diagram

the STRING was used to construct the protein-protein interaction network model

and the Cytoscape 3.7.2 software was used to construct the “brain-absorption components-target-AD” network diagram of Liuwei Dihuang pills

the Metascape database was used to perform gene ontology（GO） functional enrichment analysis and Kyoto encyclopedia of genes and genomes（KEGG） pathway enrichment analysis on the intersecting targets

the key pathways were analyzed. Through the extracorporal cell experiment

the effects of cerebrospinal fluid of Liuwei Dihuang pills on the proliferation rate in D-gal damaged PC12 cells and the levels of β-amyloid（Aβ）

1-42

reactive oxygen species（ROS）

interleukin 6（IL-6）

5-hydroxytryptamine（5-HT） and dopamine（DA） were detected. RESULTS: Liuwei Dihuang pills can significantly up-regulated the new object recognition index

the number of platform crossing and dwell time of target quadrant

and significantly shorten the localization latency in the model group rats

with statistically significant differences（P

<

0.01）

and restored hippocampal neuron morphology. By the data analysis

seven prototype brain-absorption components were found in the cerebrospinal fluid of rats treated with Liuwei Dihuang pills

including monosidine

（-）-quinic acid

ferulic acid

paeoniflorin

pantothenic acid

5-hydroxymethylfurfural and uridine. Totally 102 potential effect targets of the brain-absorption components of Liuwei Dihuang pills were screened out through network pharmacology

which shared 47 common targets with AD; 44 GO signaling pathways and 14 KEGG signaling pathways were obtained

which were closely related to Aβ deposition

Tau protein phosphorylation

oxidative stress

inflammatory response

energy metabolism and neurotransmitter levels. The results of extracorporal ell experiments showed that the cerebrospinal fluid of Liuwei Dihuang pills can significantly increased the proliferation rate of D-gal damaged PC12 cells

5-HT and DA levels

and significantly decreased Aβ

1-42

ROS and IL-6 levels

with statistically significant differences（P

<

0.01）. CONCLUSIONS: Liuwei Dihuang pills has improved learning and memory abilities of D-gal model rats

and its effects may be achieved by the brain-absorption components of Liuwei Dihuang pills through inhibiting Aβ deposition

Tau protein phosphorylation and oxidative stress

anti-inflammation

improving impaired energy metabolism and regulating neurotransmitter levels.