No abstract

Diets rich in flavanols reverse vascular dysfunction in diabetes, highlighting therapeutic potentials in cardiovascular disease.

The dentate gyrus (DG) is a region in the hippocampal formation whose function declines in association with human aging and is therefore considered to be a possible source of age-related memory decline. Causal evidence is needed, however, to show that DG-associated memory decline in otherwise healthy elders can be improved by interventions that enhance DG function. We addressed this issue by first using a high-resolution variant of functional magnetic resonance imaging (fMRI) to map the precise site of age-related DG dysfunction and to develop a cognitive task whose function localized to this anatomical site. Then, in a controlled randomized trial, we applied these tools to study healthy 50–69-year-old subjects who consumed either a high or low cocoa–containing diet for 3 months. A high-flavanol intervention was found to enhance DG function, as measured by fMRI and by cognitive testing. Our findings establish that DG dysfunction is a driver of age-related cognitive decline and suggest non-pharmacological means for its amelioration.

Diet is a major life style factor affecting human health, thus emphasizing the need for evidence-based dietary guidelines for primary disease prevention. While current recommendations promote intake of fruit and vegetables, we have limited understanding of plant-derived bioactive food constituents other than those representing the small number of essential nutrients and minerals. This limited understanding can be attributed to some extent to a lack of fundamental data describing the absorption, distribution, metabolism and excretion (ADME) of bioactive compounds. Consequently, we selected the flavanol (−)-epicatechin (EC) as an example of a widely studied bioactive food constituent and investigated the ADME of [2-14C](−)-epicatechin (300 μCi, 60 mg) in humans (n = 8). We demonstrated that 82 ± 5% of ingested EC was absorbed. We also established pharmacokinetic profiles and identified and quantified >20 different metabolites. The gut microbiome proved to be a key driver of EC metabolism. Furthermore, we noted striking species-dependent differences in the metabolism of EC, an insight with significant consequences for investigating the mechanisms of action underlying the beneficial effects of EC. These differences need to be considered when assessing the safety of EC intake in humans. We also identified a potential biomarker for the objective assessment of EC intake that could help to strengthen epidemiological investigations.

The circulating pool of bioactive NO and endothelium-dependent vasodilation is acutely increased in smokers following the oral ingestion of a flavanol-rich cocoa drink. The increase in circulating NO pool may contribute to beneficial vascular health effects of flavanol-rich food.

Diet and exercise have a profound impact on brain function. In particular, natural nutrients found in plants may influence neuronal survival and plasticity. Here, we tested whether consumption of a plant-derived flavanol, (Ϫ)epicatechin, enhances cognition in sedentary or wheel-running female C57BL/6 mice. Retention of spatial memory in the water maze was enhanced by ingestion of (Ϫ)epicatechin, especially in combination with exercise. Improved spatial memory was associated with increased angiogenesis and neuronal spine density, but not newborn cell survival, in the dentate gyrus of the hippocampus. Moreover, microarray analysis showed upregulation of genes associated with learning and downregulation of markers of neurodegeneration in the hippocampus. Together, our data show that ingestion of a single flavanol improves spatial memory retention in adult mammals.

No abstract

Oxidative and nitrosative stress is increasingly associated with the pathology of neurodegeneration and aging. The molecular mechanisms underlying oxidative/nitrosative stress-induced neuronal damage are emerging and appear to involve a mode of death in which mitogen-activated protein kinase (MAPK) signaling pathways are strongly implicated. Thus, attention is turning towards the modulation of intracellular signaling as a therapeutic approach against neurodegeneration. Both endogenous and dietary agents have been suggested as potent modulators of intracellular signal transduction, e.g. nitric oxide and flavonoids, respectively. This review addresses recent findings on the biological effects of flavonoids and nitric oxide in neurodegeneration and aims to elucidate the rationale for their prospective use as modulators of cellular signal transduction. © 2002 Elsevier Science Inc. All rights reserved.Keywords: Apoptosis; Oxidative stress; Neuron; Flavonoids; MAP kinase; JNK; ERK; Epicatechin; Nitric oxide; Mitochondria; Redox status; Polyphenols Abbreviations: AKT, serine/threonine kinase (also known as protein kinase B); AP-1, activator protein-1; Apaf-1, apoptosis protease activating factor-1; ASK1, apoptosis signal-regulating kinase-1; Bad, Bcl-2/BclX Lassociated death promoting protein; Bax, pro-apoptotic protein of the Bcl-2 family; Bcl-2, B-cell lymphoma 2: protein with anti-apoptotic properties; BclX L , long form of Bclx: anti-apoptotic protein of the Bcl-2 family; Caspase, cysteinyl aspartic acid-protease; c-Jun, mammalian equivalent of Jun: part of the AP-1 transcription complex; CREB, cAMP response element binding protein; DIABLO/smac, mitochondria-related pro-apoptotic protein: inhibits XIAP; ERK1/2, extracellular signal-related kinase; Fas, CD95: member of the TNF receptor family; GSHST, glutathione Stransferase; JNK, c-Jun amino-terminal kinase; MAPK, mitogen-activated protein kinase; MAPKK, MAPK kinase; MAPKKK, MAPKK kinase; MEK1/2, ERK1/2-specific MAPKK; MKK4/7, JNK-specific MAPKK; MSK1, mitogen-and stress-activated kinase-1; NF-B, nuclear factor of immunoglobulin k locus in B-cells; ONOO − , peroxynitrite anion; p53, pro-apoptotic tumor suppressor gene product; PI3-kinase, phosphoinositol 3-kinase; Ras, small G-protein; RNS, reactive nitrogen species; ROS, reactive oxygen species; RSK, pp90 ribosomal S6 kinase; SAPK, stressactivated protein kinase; XIAP, X-linked inhibitor of apoptosis: inhibits the activation of caspase-9