Haojie Ni, Yiyi Xiong, Min Liu+14 more · 2026 · Phytomedicine : international journal of phytotherapy and phytopharmacology · Elsevier · added 2026-04-24
The pathological mechanism of Alzheimer's disease (AD) is complex. The binding of Aβ to α7 nicotinic acetylcholine receptor (α7nAChR) contributes to neuronal damage. Sinomenine (SIN) is an alkaloid ex Show more
The pathological mechanism of Alzheimer's disease (AD) is complex. The binding of Aβ to α7 nicotinic acetylcholine receptor (α7nAChR) contributes to neuronal damage. Sinomenine (SIN) is an alkaloid extracted from the traditional Chinese medicine Qingfengteng (Sinomenium acutum). The anti-inflammatory, antioxidant, and immunomodulatory effects of SIN were confirmed to be closely associated with the α7nAChR. This study aimed to investigate whether α7nAChR serves as a pharmacological target of SIN against AD, and to evaluate the neuroprotective effects of SIN both in vivo and in vitro, focusing on the α7nAChR/Nrf2/Keap1 signaling pathway. In this study, the effects of SIN in both APP/PS1 transgenic mice and SH-SY5Y cells subjected to Aβ1-42-induced injury were assessed. The selective antagonist α-bungarotoxin (α-BTX), the agonist nicotine (Nic) of α7nAChR, and α7nAChR siRNA were employed. The cognitive function, Aβ deposition, synaptic plasticity markers, the tau protein phosphorylation, mitochondrial membrane potential, oxidative stress and the α7nAChR/Nrf2/Keap1 signaling pathway were analyzed in vivo and/or in vitro. SIN significantly enhanced learning and memory abilities in APP/PS1 mice, reduced Aβ plaque deposition and synaptic dysfunction, and inhibited hyperphosphorylation of tau protein and oxidative stress in the brain. In Aβ1-42-induced neuronal injury model, SIN alleviated apoptosis, increased BDNF and ACh levels, inhibited mitochondrial damage, stabilized calcium homeostasis, and suppressed oxidative stress. Meanwhile, SIN disrupted Nrf2-Keap1 binding to promote the Nrf2/HO-1 signaling pathway. Nevertheless, SIN effects above were inhibited by α-BTX. The knockdown of α7nAChR in vitro significantly promoted Nrf2/HO-1 pathway and BDNF expression. SIN exerts neuroprotective effect in APP/PS1 transgenic mice and Aβ1-42-induced neuronal injury by inhibiting oxidative stress via α7nAChR/Nrf2/Keap1 pathway. This study provides evidence for α7nAChR as a new target and the clinical application potential of SIN in AD treatment. Show less