Neurolymphatic formula restores meningeal and peripheral lymphatic function via VEGFR3 activation: Mechanistic validation of coptisine as a key anti-Alzheimer's compound

Background Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) accumulation with impaired lymphatic clearance, yet therapies targeting lymphatic dysfunction remain underexplored. The Neurolymphatic Formula (NLF), a traditional Chinese medicine, demonstrates lymphatic modulation potential, but its mechanistic role in AD remains unknown. Objective This study aimed to elucidate NLF's therapeutic efficacy in AD and investigate whether it enhances central and peripheral lymphangiogenesis via VEGF receptor 3 (VEGFR3) activation. Methods We evaluated NLF's pharmacological effects on behavior and AD pathology in APP/PS1 mice, including sunitinib-induced lymphatic impairment models. Underlying mechanisms were explored using network pharmacology, molecular docking, and in vitro assays on human lymphatic endothelial cells (HLECs). Results In APP/PS1 mice, 4-week NLF treatment reduced Aβ plaque burden by 43% ( p < 0.01) and improved spatial memory latency by 35% ( p < 0.05). NLF restored meningeal and mesenteric lymphatic density in sunitinib-treated mice to 82% and 133% of baseline, respectively ( p < 0.01), while upregulating serum VEGFR3 2.3-fold ( p < 0.01). To validate NLF's molecular basis, coptisine was identified as a representative VEGFR3 ligand (−7.1 Kcal/mol). In vitro, coptisine (25 μM) enhanced HLEC viability by 60%, accelerated wound closure 2.5-fold, and increased tube junctions by 75% (all p < 0.01) alongside VEGFR3 upregulation. Conclusions NLF alleviates AD pathology by promoting Aβ clearance through VEGFR3-mediated dual modulation of central and peripheral lymphatic systems. The in vitro efficacy of its constituent, coptisine, mechanistically validates this pro-lymphangiogenic pathway, highlighting NLF's therapeutic potential as a holistic lymphatic-targeted AD treatment.