thiacremonone and Memory-Disorders

Alzheimer's disease (AD) is pathologically characterized by excessive accumulation of amyloid-beta (Aβ) peptide. Evidence suggests that amyloid accumulation can be caused by oxidative stress and inflammatory responses. In this study, we examined neuroprotective effects of thiacremonone, an anti-oxidant and anti-inflammatory compound isolated from garlic. Treatment of thiacremonone significantly attenuated cognitive impairments in amyloid precursor protein (APP)/presenilin 1 (PS1) double-mutant transgenic mice. In addition, activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and extracellular signal-regulated kinase (ERK) pathways in the brain was potently inhibited by thiacremonone. We also observed that thiacremonone significantly inhibited activation of NF-κB and ERK pathways induced by H2O2 and Aβ1-42 in embryonic neuronal cells. Furthermore, thiacremonone augmented peroxiredoxin 6 (PRDX6) expression in vivo and in vitro associated with reduced oxidative stress of macromolecules such as protein and lipids. This study indicates that thiacremonone might exert memory improvement via stimulating anti-oxidant system. These multiple properties could attenuate Aβ accumulation and oxidative stress in Alzheimer's brains. Thus, these results suggest that thiacremonone might be useful to intervene development or progression of neurodegeneration in AD.

Topics: Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Animals; Antioxidants; Disease Models, Animal; DNA; Enzyme Activation; Glutathione; Lipid Peroxidation; Memory Disorders; Mice, Transgenic; Mitogen-Activated Protein Kinases; Mutation; Neurons; NF-kappa B; Oxidative Stress; Peroxiredoxin VI; Presenilin-1; Protein Binding; Protein Carbonylation; Rats, Sprague-Dawley; Thiophenes

Neuroinflammation is implicated for amyloidogenesis. Sulfur compounds extracted from garlic have been shown to have anti-inflammatory properties. Previously, we have investigated that thiacremonone, a sulfur compound isolated from garlic has anti-inflammatory effects. To investigate thiacremonone's potential effect on anti-neuroinflammation and anti-amyloidogenesis, 4 week old ICR mice were given different doses of thiacremonone (1, 3, and 10 mg/kg) in drinking water for 1 month and received intraperitoneal injection of lipopolysaccharide (LPS) (250 μg/kg/day) at last 7 days of treatment. Our data show thiacremonone decreased LPS-induced memory impairment, glial activation, pro-inflammatory mediators' expression, and amyloidogenesis. In an in vitro study, we obtained similar results, with thiacremonone (1, 2, and 5 μg/ml) effectively decreased LPS (1 μg/ml)-induced glial activation and inflammatory mediators generation which are implicated in amyloidogenesis. Our data also demonstrated that thiacremonone inhibited LPS-induced amyloidogenesis in cultured astrocytes and microglial BV-2 cells. NF-κB, a critical transcriptional factor regulating not only inflammation but also amyloid-β generation, was inhibited by thiacremonone via blocking of phosphorylation of IκBα in mice brain as well as cultured astrocytes and microglial BV-2 cells. These results indicated that the anti-inflammatory compound, thiacremonone, inhibited neuroinflammation and amyloidogenesis through inhibition of NF-κB activity, and thus could be applied for intervention of inflammation-related neurodegenerative disease including Alzheimer's disease.

Topics: Amyloid beta-Peptides; Amyloid Precursor Protein Secretases; Analysis of Variance; Animals; Animals, Newborn; Anti-Inflammatory Agents; Astrocytes; Avoidance Learning; Brain; Cell Survival; Cells, Cultured; Cerebral Cortex; Disease Models, Animal; Dose-Response Relationship, Drug; Electrophoretic Mobility Shift Assay; Exploratory Behavior; Gene Expression Regulation; Inflammation; Lipopolysaccharides; Male; Maze Learning; Memory Disorders; Mice; Mice, Inbred ICR; Nitric Oxide; Peptide Fragments; Reactive Oxygen Species; Thiophenes