Green Tea Seed Isolated Theasaponin E1 Ameliorates AD Promoting Neurotoxic Pathogenesis by Attenuating Aß Peptide Levels in SweAPP N2a Cells.

Alzheimer's disease (AD) is the most frequent type of dementia affecting memory, thinking and behaviour. The major hallmark of the disease is pathological neurodegeneration due to abnormal aggregation of Amyloid beta (Aß) peptides generated by ß- and γ-secretases via amyloidogenic pathway. Purpose of the current study was to evaluate the effects of theasaponin E1 on the inhibition of Aß producing ß-, γ-secretases (BACE1, PS1 and NCT) and acetylcholinesterase and activation of the non-amyloidogenic APP processing α-secretase (ADAM10). Additionally, theasaponin E1 effects on Aß degrading and clearing proteins neprilysin and insulin degrading enzyme (IDE). The effect of theasaponin E1 on these crucial enzymes was investigated by RT-PCR, ELISA, western blotting and fluorometric assays using mouse neuroblastoma cells (SweAPP N2a). theasaponin E1 was extracted and purified from green tea seed extract via HPLC, and N2a cells were treated with different concentrations for 24 h. Gene and protein expression in the cells were measured to determine the effects of activation and/or inhibition of theasaponin E1 on ß- and γ-secretases, neprilysin and IDE. Results demonstrated that theasaponin E1 significantly reduced Aß concentration by activation of the α-secretase and neprilysin. The activities of ß- and γ-secretase were reduced in a dose-dependent manner due to downregulation of BACE1, presenilin, and nicastrin. Similarly, theasaponin E1 significantly reduced the activity of acetylcholinesterase. Overall, from the results it is concluded that green tea seed extracted saponin E1 possess therapeutic significance as a neuroprotective natural product recommended for the treatment of Alzheimer's disease.

Protective Effects of Dietary Supplementation with a Combination of Nutrients in a Transgenic Mouse Model of Alzheimer's Disease.

OBJECTIVE: This study investigated the effects of intervention with a combination of nutrients in the amyloid precursor protein-presenilin (APP-PSN) C57BL/6J double transgenic mouse model of Alzheimer's disease (AD). METHODS: A total of 72 2-month-old APP-PSN mice were randomly assigned to three groups. The model group (MG) was fed regular, unsupplemented chow, while the low- and high-dose treatment groups (LG and HG, respectively) were given a combination of nutrients that included phosphatidylserine, blueberry extracts, docosahexaenoic acid, and eicosapentaenoic acid as part of their diet. An additional 24 wild-type littermates that were fed unsupplemented chow served as the negative control group (NG). After 3 and 7 months of treatment, the cognitive performance was assessed with the Morris water maze and the shuttle box escape/avoidance task, and the biochemical parameters and oxidative stress were evaluated in both the blood and brain. RESULTS: An improvement in antioxidant capacity was observed in the treatment groups relative to the MG at 3 months, while superior behavioral test results were observed in the mice of the HG and NG groups. In the MG, pycnosis was detected in neuronal nuclei, and a loss of neurons was observed in the cerebral cortex and the hippocampus. At 7 months, the ß-amyloid1-42 peptide accumulation was significantly elevated in the MG but was markedly lower in the mice fed the nutrient combination. The antioxidant capacity and behavioral test scores were also higher in these mice. CONCLUSIONS: Early intervention with a combination of nutrients should be considered as a strategy for preventing cognitive decline and other symptoms associated with AD.

Anti-inflammatory treatment in AD mice protects against neuronal pathology.

Prior studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may lower the incidence of Alzheimer's disease (AD) and delay onset or slow progression of symptoms in mouse models of AD. We examined the effects of chronic NSAID treatment in order to determine which elements of the pathological features might be ameliorated. We compared the effects of the NSAIDs ibuprofen and celecoxib on immunohistological and neurochemical markers at two different ages in APPxPS1 mice using measurements of amyloid plaque deposition, Abeta peptide levels, and neurochemical profiles using magnetic resonance spectroscopy (MRS). At 6 months of age, few neurochemical changes were observed between PSAPP mice and WT mice using MRS. Ibuprofen, but not celecoxib, treatment significantly decreased the Abeta(42/40) ratio in frontal cortex at 6 months, but overall amyloid plaque burden was unchanged. Consistent with prior findings in mouse models, at 17 months of age, there was a decrease in the neuronal markers NAA and glutamate and an increase in the astrocytic markers glutamine and myo-inositol in AD mice compared to WT. Ibuprofen provided significant protection against NAA and glutamate loss. Neither of the drugs significantly affected myo-inositol or glutamine levels. Both ibuprofen and celecoxib lowered plaque burden without a significant effect on Abeta(1-42) levels. NAA levels significantly correlated with plaque burden. These results suggest that selective NSAIDs (ibuprofen and possibly celecoxib) treatment can protect against the neuronal pathology.