PI3K-Akt signaling pathway based on network pharmacology for the anti-Alzheimer’s disease effect of licorice stem flavonoids

Active ingredients were screened by TCMSP and swissADME, meanwhile, PharmMapper combined with UniProt database was used to predict the active ingredient target information, GeneCard database was employed to obtain Alzheimer's disease (AD)-related genes, Cytoscapes 3.7.2 software was utilized to map the active ingredient-target effect. Besides, Cytoscapes 3.7.2 software Bisogenet and Cyto NCA plug-in combined with STRING platform were utilized to map the protein-protein interaction (PPI) network, DAVID was employed for GO annotation, while KEGG plug-in was used for KEGG pathway enrichment. Mice were tested for inflammatory damage induced by intracerebral injection of lipopolysaccharide (LPS), as well as learning memory and anxiety by water maze and open field tests. In addition, the expression of Caspase-3 and Caspase-9, together with inflammatory factors TNF-α, IL-6, and IL-1β was analyzed in serum. The expression levels of proteins related to PI3K-Akt signaling pathway in the brain were detected by Western blot (WB) assay. According to the results of network pharmacology, there were 35 active ingredients of licorice stem and leaf flavonoids screened, which exerted the anti-Alzheimer's disease (AD) effects via 67 targets and activated 41 signaling pathways including the PI3K-Akt pathway. Furthermore, Behavioural results revealed that Licorice stem and leaf flavonoids improved the learning and memory abilities of model mice and significantly improved the anxiety caused by inflammatory brain damage. Moreover, as suggested by HE staining and TUNEL staining of brain sections, Glycyrrhiza glabra stem and leaf flavonoids alleviated morphological lesions and cell nuclear damage in brain tissue. Results: of brain homogenate supernatant assay demonstrated that Glycyrrhiza glabra stem and leaf flavonoids had a significant effect on the levels of oxidative indicators superoxide dismutase (SOD), catalase (CAT), malonaldehyde (MDA), acetylcholine (Ach), acetylcholinesterase (AchE), Caspase-3, Caspase-9 and serum inflammatory factors TNF-α, IL-6 and IL-1β. Additionally, WB assay results indicated that the PI3K-Akt signaling pathway was activated.