Chinese medicine monomers in the treatment of Alzheimer’s disease: Some preclinical findings

Abstract Background Most of the FDA approved drugs for AD are symptom driven and effects are limited. Because AD is a complex disease involving multiple pathological changes, such as senile plaques formed by amyloid‐β (Aβ) deposition, neurofibrillary tangles caused by tau hyperphosphorylation, microglia‐evoked neuroinflammation, synaptic degeneration, and blood‐brain barrier (BBB) disruption. While the current anti‐dementia drugs are mostly single targets, Chinese medicines have great development potential considering their multi‐target anti‐dementia components. Method Several Chinese medicine monomers, including cryptotanshinone (CTS), pterostilbene (PTE), Ginsenoside Compound K (GCK), and glabridin (Gla) were selected to test their safety and efficacy in AD cell models, and to further explore their possible molecular mechanisms and target of action. Aβ42 oligomers (AβO) were used to establish AD cell models. The cytotoxicity of AβO as well as protective effects of Chinese medicine monomers on cell models were evaluated using the MTT assay. The molecular mechanisms and pathways were tested using qRT‐PCR, ELISA, Western blot and immunofluorescence. Result AβO induced cell injury, apoptosis, and generation of intracellular reactive oxygen species (ROS). In AβO‐induced cell models, CTS significantly reduced tau hyperphosphorylation at Ser202, Ser404, Thr181, and Thr231, and increased the levels of PSD95 and synaptophysin; PTE attenuated cell injury, apoptosis, and ROS generation; GCK diminished inflammatory cytokine production; Gla attenuated cell injury (figure1). Further study found that their mechanisms of action include PI3K/Akt/GSK3β pathway (figure2), BBB permeability and tight junction scaffold protein (figure3), as well as NF‐kB pathway via LRP1 activation (figure4), respectively. Conclusion These results provides rational basis for the therapeutic application of Chinese medicine monomers in the treatment of AD, and support further evaluation of these multi‐target action potential in AD treatment.