The Neuroprotection of Verbascoside in Alzheimer's Disease Mediated through Mitigation of Neuroinflammation via Blocking NF-κB-p65 Signaling

Verbascoside (VB) is a phenylethanoid glycoside extracted from the herbaceous plant Verbascum sinuatum and plays a neuroprotective role in Alzheimer's disease (AD). The goal of this study was to explore the neuroprotective mechanism of VB. Based on the proteomics analysis, immunohistochemistry, immunofluorescence, Western blot, and ELISA were utilized to explore the neuroprotective mechanism of VB in context of neuroinflammation in APP/PS1 mice, LPS-induced BV2 cells, and/or A beta(1-42)-stimulated N2a cells. Proteomic analysis demonstrated that the neuroprotection of VB correlated closely to its anti-inflammatory effect. VB significantly blocked microglia and astrocyte against activation in brains of APP/PS1 mice, suppressed the generation of IL-1 beta as well as IL-6, and boosted that of IL-4, IL-10 and TGF-beta in vivo, which were analogous to results acquired in vitro. Furthermore, VB effectively restrained the phosphorylation of IKK alpha+beta, I kappa B alpha, and NF-kappa B-p65 in APP/PS1 mice; LPS-induced BV2 cells, and A beta(1-42)-stimulated N2a cells and lowered the tendency of NF-kappa B-p65 translocation towards nucleus in vitro. These results demonstrate that the neuroprotective effect of VB correlates to the modulation of neuroinflammation via NF-kappa B-p65 pathway, making VB as a hopeful candidate drug for the prevention and treatment of AD.