Oxidative insults to neurons and synapse are prevented by aged garlic extract and S-allyl-L-cysteine treatment in the neuronal culture and APP-Tg mouse model

J Neurochem. 2011 May;117(3):388-402. doi: 10.1111/j.1471-4159.2010.07145.x. Epub 2011 Mar 14.

Abstract

Alzheimer's disease (AD) is one of the most common forms of dementia in the elderly. In AD patients, β-amyloid peptide (Aβ) plaques and neurofibrillary tangles are common features observed in the CNS. Aβ deposition results in the production of reactive oxygen species (ROS) leading to the hyperphosphorylation of tau that are associated with neuronal damage. Cholinesterase inhibitors and a partial NMDA receptor antagonist (memantine) have been identified as potential treatment options for AD. However, clinical studies have found that these drugs fail to prevent the disease progression. From ancient times, garlic (Allium sativum) has been used to treat several diseases. By 'aging' of garlic, some adverse reactions of garlic can be eliminated. Recent findings suggest that 'aged garlic extract' (AGE) may be a therapeutic agent for AD because of its antioxidant and Aβ lowering properties. To date, the molecular properties of AGE have been sparsely studied in vitro or in vivo. The present study tested specific biochemical and molecular effects of AGE in neuronal and AD rodent models. Furthermore, we identified S-allyl-L-cysteine (SAC) as one of the most active chemicals responsible for the AGE-mediated effect(s). We observed significant neuroprotective and neurorescue properties of AGE and one of its ingredients, SAC, from ROS (H(2)O(2))-mediated insults to neuronal cells. Treatment of AGE and SAC were found to protect neuronal cells when they were independently co-treated with ROS. Furthermore, a novel neuropreservation effect of AGE was detected in that pre-treatment with AGE alone protected ∼ 80% neuronal cells from ROS-mediated damage. AGE was also found to preserve pre-synaptic protein synaptosomal associated protein of 25 kDa (SNAP25) from ROS-mediated insult. For example, treatment with 2% AGE containing diet and SAC (20 mg/kg of diet) independently increased (∼70%) levels of SNAP25 and synaptophysin in Alzheimer's amyloid precursor protein-transgenic mice, of which the latter was significantly decreased in AD. Taken together, the neuroprotective, including preservation of pre-synaptic proteins by AGE and SAC can be utilized in future drug development in AD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / drug therapy
  • Alzheimer Disease / genetics
  • Alzheimer Disease / pathology*
  • Alzheimer Disease / physiopathology
  • Amyloid beta-Peptides / metabolism
  • Amyloid beta-Protein Precursor / genetics
  • Analysis of Variance
  • Animals
  • Cell Line, Transformed
  • Cysteine / analogs & derivatives*
  • Cysteine / pharmacology
  • Cysteine / therapeutic use
  • Disease Models, Animal
  • Exploratory Behavior / drug effects
  • Garlic / chemistry*
  • Gene Expression Regulation / drug effects
  • Humans
  • Hydrogen Peroxide / adverse effects
  • L-Lactate Dehydrogenase / metabolism
  • Memory, Short-Term / drug effects
  • Mice
  • Mice, Transgenic
  • Neurons / drug effects*
  • Neuroprostanes / pharmacology*
  • Neuroprostanes / therapeutic use
  • Plant Extracts / pharmacology*
  • Plant Extracts / therapeutic use
  • Rats
  • Reactive Oxygen Species / adverse effects
  • Synapses / drug effects*
  • Synaptophysin / metabolism
  • Synaptosomal-Associated Protein 25 / metabolism
  • Time Factors

Substances

  • Amyloid beta-Peptides
  • Amyloid beta-Protein Precursor
  • Neuroprostanes
  • Plant Extracts
  • Reactive Oxygen Species
  • Snap25 protein, mouse
  • Synaptophysin
  • Synaptosomal-Associated Protein 25
  • S-allylcysteine
  • Hydrogen Peroxide
  • L-Lactate Dehydrogenase
  • Cysteine