Cyanidin-3-O-glucoside protects the brain and improves cognitive function in APPswe/PS1E9 transgenic mice model

Cyanidin-3-O-glucoside (C3G) is a natural anthocyanin with antioxidant, anti-inflammatory, and antitumor properties. However, as the effects of C3G on the amyloidogenic pathway, autophagy, tau phosphorylation, neuronal cell death, and synaptic plasticity in Alzheimer's disease models have not been reported, we attempted to investigate the same in the brains of APPswe/PS1 Delta E9 mice were analyzed. After oral administration of C3G (30 mg/kg/day) for 16 weeks, the cortical and hippocampal regions in the brains of APPswe/PS1 Delta E9 mice were analyzed. C3G treatment reduced the levels of soluble and insoluble A beta (A beta 40 and A beta 42) peptides and reduced the protein expression of the amyloid precursor protein, presenilin-1, and beta-secretase in the cortical and hippocampal regions. And C3G treatment upregulated the expression of autophagy-related markers, LC3B-II, LAMP-1, TFEB, and PPAR-alpha and downregulated that of SQSTM1/p62, improving the autophagy of A beta plaques and neurofibrillary tangles. In addition, C3G increased the protein expression of phosphorylated-AMPK/AMPK and Sirtuin 1 and decreased that of mitogen-activated protein kinases, such as phosphorylated-Akt/Akt and phosphorylated-ERK/ERK, thus demonstrating its neuroprotective effects. Furthermore, C3G regulated the PI3K/Akt/GSK3 beta signaling by upregulating phosphorylated-Akt/Akt and phosphorylated-GSK3 beta/GSK3 beta expression. C3G administration mitigated tau phosphorylation and improved synaptic function and plasticity by upregulating the expression of synapse-associated proteins synaptophysin and postsynaptic density protein-95. Although the potential of C3G in the APPswe/PS1 Delta E9 mouse models has not yet been reported, oral administration of the C3G is shown to protect the brain and improve cognitive behavior.