Polyphenols are found ubiquitously in plants and their regular consumption has been associated with a reduced risk of a number of chronic diseases, including cancer, cardiovascular disease (CVD) and neurodegenerative disorders. Rather than exerting direct antioxidant effects, the mechanisms by which polyphenols express these beneficial properties appear to involve their interaction with cellular signaling pathways and related machinery that mediate cell function under both normal and pathological conditions. We illustrate that their interactions with two such pathways, the MAP kinase (ERK, JNK, p38) and PI3 kinase/Akt signaling cascades, allow them to impact upon normal and abnormal cell function, thus influencing the cellular processes involved in the initiation and progression of cancer, CVD and neurodegeneration. For example, their ability to activate ERK in neurons leads to a promotion of neuronal survival and cognitive enhancements, both of which influence the progression of Alzheimer's disease, whilst ERK activation by polyphenols in vascular endothelial cells influences nitric oxide production, blood pressure and ultimately CVD risk. The main focus of this review is to provide an overview of the role that polyphenols play in the prevention of cancer, cardiovascular disease and neurodegeneration. We present epidemiological data, human intervention study findings, as well as animal and in vitro studies in support of these actions and in each case we consider how their actions at the cellular level may underpin their physiological effects.

Polyphenols and Human Health: Prevention of Disease and Mechanisms of Action

Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed.

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Melatonin: buffering the immune system.

Stress, serotonin, and hippocampal neurogenesis in relation to depression and antidepressant effects

Moringa oleifera (M. oleifera) is an angiosperm plant, native of the Indian subcontinent, where its various parts have been utilized throughout history as food and medicine. It is now cultivated in all tropical and sub-tropical regions of the world. The nutritional, prophylactic, and therapeutic virtues of this plant are being extolled on the Internet. Dietary consumption of its part is therein promoted as a strategy of personal health preservation and self-medication in various diseases. The enthusiasm for the health benefits of M. oleifera is in dire contrast with the scarcity of strong experimental and clinical evidence supporting them. Fortunately, the chasm is slowly being filled. In this article, I review current scientific data on the corrective potential of M. oleifera leaves in chronic hyperglycemia and dyslipidemia, as symptoms of diabetes and cardiovascular disease (CVD) risk. Reported studies in experimental animals and humans, although limited in number and variable in design, seem concordant in their support for this potential. However, before M. oleifera leaf formulations can be recommended as medication in the prevention or treatment of diabetes and CVD, it is necessary that the scientific basis of their efficacy, the therapeutic modalities of their administration and their possible side effects be more rigorously determined.

https://ruor.uottawa.ca/bitstream/10393/22841/1/Mbikay_Majambu_2012_Therapeutic_potential_of_moringa_oleifera_leaves.pdf

Therapeutic potential of Moringa oleifera leaves in chronic hyperglycemia and dyslipidemia: a review

The brain is a metabolically active organ exhibiting high oxygen consumption and robust production of reactive oxygen species (ROS) The large amounts of ROS are kept in check by an elaborate network of antioxidants, which sometimes fail and lead to neuronal oxidative stress Thus, ROS are typically categorized as neurotoxic molecules and typically exert their detrimental effects via oxidation of essential macromolecules such as enzymes and cytoskeletal proteins Most importantly, excessive ROS are associated with decreased performance in cognitive function However, at physiological concentrations, ROS are involved in functional changes necessary for synaptic plasticity and hence, for normal cognitive function The fine line of role reversal of ROS from good molecules to bad molecules is far from being fully understood This review focuses on identifying the multiple sources of ROS in the mammalian nervous system and on presenting evidence for the critical and essential role of ROS in synaptic plasticity and memory The review also shows that the inability to restrain either age- or pathology-related increases in ROS levels leads to opposite, detrimental effects that are involved in impairments in synaptic plasticity and memory function Antioxid Redox Signal 14, 2013–2054

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Reactive oxygen species in the regulation of synaptic plasticity and memory.

A study of brain insulin receptors, AChE activity and oxidative stress in rat model of ICV STZ induced dementia.

Insulin receptor signaling in rat hippocampus: A study in STZ (ICV) induced memory deficit model

Effect of curcumin on brain insulin receptors and memory functions in STZ (ICV) induced dementia model of rat.

Rare dipeptide and urea derivatives from roots of Moringa oleifera as potential anti-inflammatory and antinociceptive agents.

Purpose of Study
To discuss studies in humans and animals revealing the ability of foods to benefit the brain: new information with regards to mechanisms of action and the treatment of neurological and psychiatric disorders.

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Ethika Tyagi

Papers

A study of brain insulin receptors, AChE activity and oxidative stress in rat model of ICV STZ induced dementia.

Insulin receptor signaling in rat hippocampus: A study in STZ (ICV) induced memory deficit model

Effect of curcumin on brain insulin receptors and memory functions in STZ (ICV) induced dementia model of rat.

Rare dipeptide and urea derivatives from roots of Moringa oleifera as potential anti-inflammatory and antinociceptive agents.

Diet and cognition: interplay between cell metabolism and neuronal plasticity.