Article

Long-term administration of green tea catechins improves spatial cognition learning ability in rats

Department of Environmental Physiology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan.
Journal of Nutrition (Impact Factor: 3.88). 05/2006; 136(4):1043-7.
Source: PubMed

ABSTRACT

Green tea catechins confer potent biological properties including antioxidation and free-radical scavenging. We investigated the effect of long-term oral administration of green tea catechins (Polyphenon E, PE: EGCG 63%; EC 11%; EGC 6%; ECG 6%) mixed with water on the spatial cognition learning ability of young rats. The learning ability of rats administered PE (0%, 0.1%, 0.5%) for 26 wk was assessed in the partially baited 8-arm radial maze. Relative to controls, those administered PE had improved reference and working memory-related learning ability. They also had lower plasma concentrations of lipid peroxides and greater plasma ferric-reducing antioxidation power than controls. Furthermore, rats administered PE had lower hippocampus reactive oxygen species concentrations than controls. We suggest that this improvement in spatial cognitive learning ability is due to the antioxidative activity of green tea catechins.

Download full-text

Full-text

Available from: Michio Hashimoto, Mar 22, 2014
  • Source
    • "Within the polyphenol family, flavonoids have been shown to ameliorate learning and memory in both animals and humans. Flavanols, and particularly epicatechin and catechin, present in grape seeds, green tea or cocoa for example, have been shown to ameliorate learning and memory in animals (Devi et al., 2006; Haque et al., 2006; van Praag et al., 2007; Kaur et al., 2008; Asha Devi et al., 2011; Rendeiro et al., 2013b) and in humans (Dinges, 2006). Anthocyanins, present in red berries as in blueberries, have also been shown to prevent memory deficits in aged animals (Cho et al., 2003; Ramirez et al., 2005; Barros et al., 2006; Shukitt-Hale et al., 2006; Rendeiro et al., 2013b). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Spatial learning and memory deficits associated with hippocampal synaptic plasticity impairments are commonly observed during aging. Besides, the beneficial role of dietary polyphenols has been suggested as potential functional food candidates to prevent this memory decline. Indeed, polyphenols could potentiate the signaling pathways of synaptic plasticity underlying learning and memory. In this study, spatial learning deficits of middle-aged mice were first highlighted and characterized according to their navigation patterns in the Morris water maze task. An eight-week polyphenol-enriched diet, containing a polyphenol-rich extract from grape and blueberry (PEGB; from the Neurophenols Consortium) with high contents of flavonoids, stilbenes and phenolic acids, was then successful in reversing these age-induced effects. The use of spatial strategies was indeed delayed with aging whereas a polyphenol supplementation could promote the occurrence of spatial strategies. These behavioral results were associated with neurobiological changes: while the expression of hippocampal calmodulin kinase II (CaMKII) mRNA levels was reduced in middle-aged animals, the polyphenol-enriched diet could rescue them. Besides, an increased expression of nerve growth neurotrophic factor (NGF) mRNA levels was also observed in supplemented adult and middle-aged mice. Thus these data suggest that supplementation with polyphenols could be an efficient nutritional way to prevent age-induced cognitive decline.
    Full-text · Article · Feb 2016 · Frontiers in Behavioral Neuroscience
  • Source
    • "In fact, EGCG can easily cross the BBB and reach the brain parenchyma [124]. Besides, long term administration was shown to improve spatial cognition and learning ability in rats [125] and to reduce cerebral amyloidosis in AD transgenic mice [126]. Moreover, the consumption of EGCG inhibits OS-induced neuronal degeneration and cell death in pre-and post-traumatic brain injury [127]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Diabetes mellitus (DM) is a metabolic disease that is rapidly increasing and has become a major public health problem. Type 2 DM (T2DM) is the most common type, accounting for up to 90-95% of the new diagnosed DM cases. The brain is very susceptible to glucose fluctuations and hyperglycemia-induced oxidative stress (OS). It is well known that DM and the risk of developing neurodegenerative diseases are associated. Tea, Camellia sinensis L., is one of the most consumed beverages. It contains several phytochemicals, such as polyphenols, methylxanthines (mainly caffeine) and L-theanine that are often reported to be responsible for tea’s health benefits, including in brain. Tea phytochemicals have been reported to be responsible for tea’s significant antidiabetic and neuroprotective properties and antioxidant potential. Epidemiological studies have shown that regular consumption of tea has positive effects on DM-caused complications and protects the brain against oxidative damage, contributing to an improvement of the cognitive function. Among the several reported benefits of tea consumption, those related with neurodegenerative diseases are of great interest. Herein, we discuss the potential beneficial effects of tea consumption and tea phytochemicals on DM and how their action can counteract the severe brain damage induced by this disease.
    Full-text · Article · Dec 2014 · Current Neuropharmacology
  • Source
    • "Catechins and epigallocatechin-3-gallate (EGCG) are abundant in teas derived from the tea plant Camellia sinensis. These products show the effect of ameliorating a variety of human diseases such as cancers, atherosclerotic lesions, and Alzheimer's disease [66–70]. Recent studies [37, 38] have shown that they also attenuate the Helicobacter pylori-triggered caspase-1 signaling pathway, oxidative stress, and apoptosis in the gastric mucosa of the Helicobacter pylori-infected mouse model. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Aging, a natural physiological process, is characterized by a progressive loss of physiological integrity. Loss of cellular homeostasis in the aging process results from different sources, including changes in genes, cell imbalance, and dysregulation of the host-defense systems. Innate immunity dysfunctions during aging are connected with several human pathologies, including metabolic disorders and cardiovascular diseases. Recent studies have clearly indicated that the decline in autophagic capacity that accompanies aging results in the accumulation of dysfunctional mitochondria, reactive oxygen species (ROS) production, and further process dysfunction of the NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome activation in the macrophages, which produce the proinflammatory cytokines. These factors impair cellular housekeeping and expose cells to higher risk in many age-related diseases, such as atherosclerosis and type 2 diabetes. In this review, we investigated the relationship between dysregulation of the inflammasome activation and perturbed autophagy with aging as well as the possible molecular mechanisms. We also summarized the natural compounds from food intake, which have potential to reduce the inflammasome activation and enhance autophagy and can further improve the age-related diseases discussed in this paper.
    Full-text · Article · Sep 2014 · BioMed Research International
Show more