Table 1 The beneficial role of selected polyphenolic compounds in Alzheimer’s disease
Polyphenolic compounds | Target and role | Properties | Key references |
---|---|---|---|
Resveratrol | Aβ pathway | Remodels soluble oligomers and fibrils form into nontoxic form of Aβ | Ladiwala et al. [73] |
Aβ pathway | Reduction of production of Aβ peptides in vitro | Marambaud et al. [74] | |
Cytoprotection | Protect cells from Aβ-induced toxicity | Han et al. [75] | |
Oxidative markers | Decrease of ROS and lipid peroxide levels in animal models | Haque et al. [76] | |
Synaptic density | Decrease of cognitive deficits in animal models | Kumar et al. [77] | |
Specific proteins | Reduced the number of lysosomes and Aβ-induced toxicity | Regitz et al. [78] | |
Mitophagy pathway | Reduced apoptosis, decreased oxidative status, and alleviated mitochondrial damage in Aβ1–42-treated PC12 cells | Wang et al. [79] | |
Inhibiting the increase of protein kinase A and activation of PI3K/Akt signaling pathway | Alleviates Aβ25–35-induced dysfunction in hippocampal CA1 pyramidal neurons via recovery of the function of transient potassium channel and delay rectifier potassium channel by inhibiting the increase of protein kinase A and the activation of PI3K/Akt signaling pathway | Yin et al. [80] | |
Curcumin | Aβ pathway | Reduction of BACE-1 mRNA | Liu et al. [81] |
Aβ pathway | Reduction of the formation of Aβ fibrils | Ono et al. [82] | |
Aβ pathway | Reduction of Aβ deposits and senile plaques in Tg2576 mice model | Yang et al. [83] Garcia-Alloza et al. [84] Lim et al. [85] Frautschy et al. [86] | |
Cytoprotection | Protect cells from Aβ-induced toxicity | Kim et al. [87] | |
Inflammatory pathways | Reduction of Aβ-induced expression of cytokines and chemokines | Lim et al. [85] | |
Synaptic density | Increase of post-synaptic density-95 in vitro in the brain of Aβ-injected rats | Frautschy et al. [86] | |
Cognitive deficits | Decrease of cognitive deficits in animal models | Frautschy et al. [86] Ishrat et al. [88] | |
Catechins | Aβ pathway | Reduction in the translation of APP mRNA | Levites et al. [71] |
Aβ pathway | Increase α-secretase activity; reduction in the production of Aβ peptides in APP695 over-expressing neurons | Rezai-Zadeh et al. [89] | |
Aβ pathway | Reduction in β-secretase activity | Jeon et al. [90] | |
Aβ pathway | Reduction in the formation of Aβ fibrils by binding to the native unfolded Aβ | Levites et al. [71] Ehrnhoefer et al. [91] Bieschke et al. [92] | |
Cytoprotection | Protect cells from Aβ-induced toxicity | Levites et al. [71] Bieschke et al. [92] | |
Cytoprotection | Reduction in Aβ-induced caspase activity in hippocampal neuronal cells | Choi et al. [70] | |
Inflammatory pathways | Reduction in Aβ-induced cytokines in human astrocytoma U373MG cells | Kim et al. [93] | |
Oxidative markers | Reduction in Aβ-induced levels of lipid oxidation in hippocampal neuronal cells | Choi et al. [70] | |
Cognitive deficits | Decrease of cognitive deficits in animal models | Rezai-Zadeh et al. [89] Haque et al. [76] |