Antidepressant mechanisms of a food-medicine homologous compound concentrate from Hemerocallis citrina Baroni: Regulation of PI3K/AKT/BDNF signaling pathway in preclinical models

Objective: To determine the optimal dosing ratio of the herbal components within compound Hemerocallis citrina Baroni (H. citrina) extract concentrate (CHEC), evaluate its antidepressant effects in zebrafish and mouse models of depression, and elucidate the underlying mechanisms with a particular focus on the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/brain-derived neurotrophic factor (BDNF) signaling pathway using network pharmacology and molecular biology approaches. Methods: The optimal CHEC formulation was screened using a zebrafish model of reserpine-induced depression. To assess neuroinflammation and monoamine neurotransmitter levels, the levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, dopamine, and 5-hydroxytryptamine in zebrafish brain tissues were measured using enzyme-linked immunosorbent assay kits. Active constituents were identified by liquid chromatography-tandem mass spectrometry and potential targets were predicted using the Swiss Target Prediction database. A traditional Chinese medicine–active ingredient–target network and a protein–protein interaction network were constructed, followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses to explore potential mechanisms. A mouse model of depression was subsequently established using chronic restraint stress (CRS) combined with intraperitoneal lipopolysaccharide injection. The antidepressant effects of CHEC were assessed through behavioral tests, quantification of monoamine neurotransmitters and inflammatory cytokines, histopathological examination of hippocampal neurons using hematoxylin and eosin staining, and Western blot analysis of PI3K/AKT/BDNF pathway-related proteins. Results: CHEC significantly alleviated depressive-like behaviors in CRS mice, as demonstrated by behavioral assessments. Treatment reduced levels of pro-inflammatory cytokines and restored monoamine neurotransmitter concentrations. Histological analysis revealed attenuation of hippocampal neuronal damage. Furthermore, CHEC significantly modulated the PI3K/AKT/BDNF signaling pathway in the hippocampus of depressive-like mice. Conclusion: CHEC exerts antidepressant-like effects by suppressing inflammatory cytokines, including tumor necrosis factor-alpha, IL-6, and IL-1β; enhancing dopamine and BDNF levels; and regulating the PI3K/AKT/BDNF signaling pathway. These findings provide mechanistic evidence supporting the therapeutic potential of CHEC for depression.