Cognition enhancing effect of the aqueous extract of Cinnamomum zeylanicum on non-transgenic Alzheimer's disease rat model: Biochemical, histological, and behavioural studies.
OBJECTIVE
Several dietary supplements are actively being tested for their dual role of alleviating the metabolic perturbations and restricting the consequent cognitive dysfunctions seen in neurodegenerative disorders such as Alzheimer's disease (AD). The aim of the current study was to assess the influence of aqueous extract of cinnamon (CE) on the monosodium glutamate-induced non-transgenic rat model of AD (NTAD) established with insulin resistance, hyperglycaemia, neuronal loss, and cognitive impairment at a very early stage of life.


METHODS
The experimental design included oral administration of CE (50 mg/kg body weight) for 20 weeks to 2-month and 10-month-old NTAD rats. Following the treatments, the animals attained 7 and 15 months of age, respectively. They were then subjected to behavioural testing, biochemical analysis, and stereology experiments.


RESULTS
The results demonstrated that CE treatment improved the insulin sensitivity, increased phosphorylated glycogen synthase kinase-3β (pGSK3β), inhibited the cholinesterase activity, and improved the learning ability in NTAD rats. Histological evaluation has shown an increase in neuron count in the DG sub-field of hippocampus upon treatment with CE.


CONCLUSIONS
These beneficial effects of CE are suggestive of considering cinnamon as a dietary supplement in modulating the metabolic changes and cognitive functions.
a Department of Neurochemistry , National Institute of Mental Health and Neurosciences , Bangalore 560 029 , India.
Sowmya
S
Madhavadas
a Department of Neurochemistry , National Institute of Mental Health and Neurosciences , Bangalore 560 029 , India.
Sarada
S
Subramanian
D000544:Alzheimer Disease / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D000818:Animals; D001522:Behavior, Animal; D002935:Cinnamomum zeylanicum / Q000737:chemistry*; D019587:Dietary Supplements; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000187:drug effects; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D007333:Insulin Resistance; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000627:therapeutic use; D018697:Nootropic Agents / Q000627:therapeutic use*; D009929:Organ Size / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000627:therapeutic use*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D017207:Rats, Sprague-Dawley; D012970:Sodium Glutamate / Q000633:toxicity
D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D018697:Nootropic Agents; D010936:Plant Extracts; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D012970:Sodium Glutamate
Alzheimer's disease; Cholinesterase; Cinnamomum zeylanicum; Cognition; Glycogen synthase kinase-3β; Hippocampus