Etudes Compléments alimentaires

Actions santé de la mélatonine

11/01/2019 | Etudes sur les hormones et Echauffement et blessures et Etudes Compléments alimentaires et Etudes Anti-âge

 

The multiple protective roles and molecular mechanisms of melatonin and its precursor N-acetylserotonin in targeting brain injury and liver damage and in maintaining bone health
ChengliangLuoa       Free Radical Biology and Medicine Volume 130, January 2019, Pages 215-233

Highlights
• Melatonin and NAS are protective agents for brain injury, liver damage and bone health.
• Melatonin and NAS are anti-oxidative stress and anti-inflammation.
• Melatonin and NAS are against autophagy dysfunction and anti-apoptosis.
• MT1/MT2 are needed for brain and liver injuries and MT2 is important for bone health.
• Melatonin and NAS will be likely to show utility in clinical trials.

Melatonin is a neurohormone associated with sleep and wakefulness and is mainly produced by the pineal gland. Numerous physiological functions of melatonin have been demonstrated including anti-inflammation, suppressing neoplastic growth, circadian and endocrine rhythm regulation, and its potent antioxidant activity as well as its role in regeneration of various tissues including the nervous system, liver, bone, kidney, bladder, skin, and muscle, among others.

In this review, we summarize the recent advances related to the multiple protective roles of melatonin receptor agonists, melatonin and N-acetylserotonin (NAS), in brain injury, liver damage, and bone health. Brain injury, including traumatic brain injury, ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, and newborn perinatal hypoxia-ischemia encephalopathy, is a major cause of mortality and disability. Liver disease causes serious public health problems and various factors including alcohol, chemical pollutants, and drugs induce hepatic damage. Osteoporosis is the most common bone disease in humans. Due in part to an aging population, both the cost of care of fracture patients and the annual fracture rate have increased steadily. Despite the discrepancy in the pathophysiological processes of these disorders, time frames and severity, they may share several common molecular mechanisms. Oxidative stress is considered to be a critical factor in these pathogeneses. We update the current state of knowledge related to the molecular processes, mainly including anti-oxidative stress, anti-apoptosis, autophagy dysfunction, and anti-inflammation as well as other properties of melatonin and NAS. Particularly, the abilities of melatonin and NAS to directly scavenge oxygen-centered radicals and toxic reactive oxygen species, and indirectly act through antioxidant enzymes are disscussed. In this review, we summarize the similarities and differences in the protection provided by melatonin and/or NAS in brain, liver and bone damage.

We analyze the involvement of melatonin receptor 1A (MT1), melatonin receptor 1B (MT2), and melatonin receptor 1C (MT3) in the protection of melatonin and/or NAS. Additionally, we evaluate their potential clinical applications. The multiple mechanisms of action and multiple organ-targeted properties of melatonin and NAS may contribute to development of promising therapies for clinical trials.

Combien de mélatonine pour la santé?

26/12/2018 | Etudes sur les hormones et Etudes Compléments alimentaires et Etudes Anti-âge

 

Melatonin as a chronobiotic/cytoprotector: its role in healthy aging
Daniel P. Cardinali         Biological Rhythm Research Volume 50, 2019 - Issue 1

Preservation of sleep, a proper nutrition and adequate physical exercise are key elements for healthy aging. Aging causes sleep alterations, and in turn, sleep disturbances lead to numerous pathophysiological changes that accelerates the aging process. In the central nervous system, sleep loss impairs the clearance of waste molecules like amyloid-β or tau peptides. Melatonin, a molecule of unusual phylogenetic conservation present in all known aerobic organisms, is effective both as a chronobiotic and a cytoprotective agent to maintain a healthy aging.

The late afternoon increase of melatonin “opens the sleep doors” every night and its therapeutic use to preserve slow wave sleep has been demonstrated. Melatonin reverses inflammaging via prevention of insulin resistance, suppression of inflammation and down regulation of proinflammatory cytokines. Melatonin increases the expression of α- and γ-secretase and decreases β-secretase expression. It also inhibits tau phosphorylation. Clinical data support the efficacy of melatonin to treat Alzheimer’s disease, particularly at the early stages of disease. From animal studies the cytoprotective effects of melatonin need high doses to become apparent (i.e. in the 40–100 mg/day range). The potentiality of melatonin as a nutraceutical is discussed.

Nouveau bénéfices de la mélatonine contre le cancer?

07/12/2018 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge

 

Adjuvant chemotherapy with melatonin for targeting human cancers: A review
Masoud Najafi         Journal of Cellular Physiology           07 September 2018

Melatonin is a multifunctional hormone that has long been known for its antitumoral effects. An advantage of the application of melatonin in cancer therapy is its ability to differentially influence tumors from normal cells. In this review, the roles of melatonin adjuvant therapy in human cancer are discussed.

Combination of melatonin with chemotherapy could provide synergistic antitumoral outcomes and resolve drug resistance in affected patients. This combination reduces the dosage for chemotherapeutic agents with the subsequent attenuation of side effects related to these drugs on normal cells around tumor and on healthy organs. The combination therapy increases the rate of survival and improves the quality of life in affected patients. Cancer cell viability is reduced after application of the combinational melatonin therapy.

Melatonin does all these functions by adjusting the signals involved in cancer progression, re‐establishing the dark/light circadian rhythm, and disrupting the redox system for cancer cells. To achieve effective therapeutic outcomes, melatonin concentration along with the time of incubation for this indoleamine needs to be adjusted. Importantly, a special focus is required to be made on choosing an appropriate chemotherapy agent for using in combination with melatonin. Because of different sensitivities of cancer cells for melatonin combination therapy, cancer‐specific targeted therapy is also needed to be considered. For this review, the PubMed database was searched for relevant articles based on the quality of journals, the novelty of articles published by the journals, and the number of citations per year focusing only on human cancers.

De la carnosine pour la régénération nerveuse?

07/12/2018 | Etudes sur les hormones et Echauffement et blessures et Etudes Compléments alimentaires et Etudes Anti-âge

 

Carnosine improves functional recovery and structural regeneration after sciatic nerve crush injury in rats
Navideh Mirzakhani             Life Sciences volume 215, 15 December 2018, Pages 22-30


Aims
Peripheral nerve injury represents a substantial clinical problem with insufficient or unsatisfactory treatment options. Current researches have extensively focused on the new approaches for the treatment of peripheral nerve injuries. Carnosine is a naturally occurring pleotropic dipeptide and has many biological functions such as antioxidant property. In the present study, we examined the regenerative ability of carnosine after sciatic nerve crush injury using behavioral, biochemical, histological and ultrastructural evaluations.

Materials and methods
Seventy-two rats were divided into six groups including control, sham, crush and carnosine (10, 20 and 40 mg/kg) groups. Crush injury in left sciatic nerve was induced by a small haemostatic forceps. Carnosine was administered for 15 consecutive days after induction of crush injury. Sciatic functional index (SFI) was recorded weekly. Histopathological and ultrastructural evaluations were made using light and electron microscopes, respectively. Sciatic nerve tissue malondialdehyde (MDA), superoxide dismutase (SOD) and tumor necrosis factor-alpha (TNF-α) levels were measured. Gastrocnemius muscle weight was determined.

Key findings
Carnosine at the doses of 20 and 40 mg/kg accelerated SFI recovery. Wallerian degeneration severity and myelinated fibers density, myelin sheath thickness and diameter as well as ultrastructural changes of myelinated axons were improved. It also recovered nerve tissue biochemical (MDA, SOD and TNF-α) changes induced by crush injury. Muscle weight ratio was reached to near normal values.

Our results suggest a regenerative effect of carnosine. Inhibition of oxidative stress and inflammatory pathways, along with provocation of myelination and prevention of muscular atrophy might be involved in this effect of carnosine.

Significance
Carnosine treatment might be considered as a therapeutic agent for peripheral nerve regeneration and its functional recovery.

Le jus de cassis comme inhibiteur MAO?

10/10/2018 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge et Etudes sur les boosters sexuels et la sexualité

 

The pharmacodynamic profile of “Blackadder” blackcurrant juice effects upon the monoamine axis in humans: A randomised controlled trial
Anthony W. Watson       Nutritional Neuroscience         05 Oct 2018

Emerging evidence from human intervention trials indicates health benefits of consuming blackcurrant fruit, including improvements to cognitive performance, modulation of blood flow, regulation of blood glucose and inhibition of enzymes underpinning normal cognitive function. Of particular relevance is our previous demonstration of monoamine oxidase (MAO)-A and B inhibition after the consumption of a New Zealand “Blackadder” blackcurrant juice in humans.

The current study uses a double-blind, placebo-controlled, randomised cross- over design to assess the pharmacodynamics of the effects on platelet MAO-B inhibition and associated substrates, plasma prolactin levels and blood glucose levels after consumption of a single serve of “Blackadder” blackcurrant juice standardised to 500 mg polyphenols. Eight healthy male (20-–35 years) participants completed the trial. Measurements were obtained at baseline 15, 30, 45, 60, 100, 120, 150, 180, 240 mins and 24 h post dose.

A fast, absolute and reversible inhibition of blood platelet MAO-B (P 

< 0.001) and a significant but delayed reduction in plasma prolactin (P 

< 0.001) were observed following the consumption of “Blackadder” blackcurrant juice when compared to a placebo control. No interpretable changes in substrates of MAO or associated metabolites were seen.

These data provide a clear time course of the reversible inhibition of MAO-B after the single consumption of a of New Zealand “Blackadder” blackcurrant juice standardised at

500 mg of polyphenols and, therefore, provide a therapeutic window on which to base future nutritional interventions.

Liens Cordyceps sinensis et cancer?

02/10/2018 | Etudes Compléments alimentaires et Etudes Anti-âge et Etudes sur les boosters sexuels et la sexualité

 

Cordyceps sinensis Promotes the Growth of Prostate Cancer Cells
Ming-wei Ma           Nutrition and Cancer   01 Oct 2018

Abstract
Background: This study aims to test whether Cordyceps sinensis (CS), the most expensive Asian nutrient supplement might stimulate growth of prostate cancer cells.

Methods: Impact of CS on growth of prostate cancer was determined in vivo and in vitro.

Results: Firstly, the serum testosterone level was significantly elevated in mice fed CS. Prostate glands were significantly enlarged (weight index 0.53 ± 0.04 mg/g vs. 0.31 ± 0.04 mg/g, P = 0.006). Furthermore, cell viability was increased twofold in the androgen-responsive prostate cancer cell line (VCaP) after CS treatment. This promoting effect disappeared after bicalutamide was added. In addition, serum prostate-specific antigen (PSA) in mice bearing VCaP xenografts was significantly elevated (0.66 ± 0.04 ng/ml vs. 0.26 ± 0.06 ng/ml, P 

< 0.001) after treatment with CS. Finally, VCaP tumors in mice treated with CS grew much faster (479.2 ± 78.74 mm3 vs. 283 ± 58.97 mm3, P = 0.074). However, the above promoting effects of CS were not observed in parallel studies using the PC-3 cell line which lacks AR expression.

Conclusions:

These results suggest that CS promotes growth of prostate cancer cells by increasing production of testosterone and stimulating the AR-dependent pathway. Additional studies are required to see whether CS is safely consumed by patients with prostate cancer.

Faut-il conserver sa whey au frigo?

26/09/2018 | Etudes Compléments alimentaires

 

Génération de rougeur via les réactions de Maillard d’isolat de protéine de lactosérum (WPI) et d’acide ascorbique (vitamine C) dans des poudres séchées par pulvérisation
Chao Zhong Songwen Tan Timothy LangrishJournal of Food Engineering

Points forts
• Les réactions de Maillard de WPI et d’acide ascorbique dans les poudres séchées par pulvérisation sont étudiées.
• Le changement de couleur et la génération de fluorescence sont observés après la réaction de Maillard.
• La température de stockage affecte de manière significative les réactions de Maillard.
• Les basses températures ou le faible stockage de l’oxygène peuvent réduire les effets des réactions de Maillard.

Des rougeurs évidentes ont été observées lors du stockage et du traitement des poudres d’acide WPI-ascorbique séchées par pulvérisation. La limite inférieure de détection par observation humaine est de 0,001 g / mL pour la concentration d’ acide ascorbique (rapport AA: WPI de 1: 100). La rougeur est liée à l’ adsorption de la lumière violette (380 nm) et de la lumière bleue / verte (500 nm). L’analyse par fluorescence suggère la formation de formylthéosylpyrroles et de poly (acides aminés) réticulés. L’analyse DSC montre que les pics d’acide ascorbique disparaissent sous forme de réaction de Maillard. La température de stockage s’est avérée affecter de manière significative les réactions de Maillard entre le WPI et l’acide ascorbique.

Les résultats montrent que les taux de réaction de Maillard entre WPI et acide ascorbique sont rapides dans les poudres séchées par pulvérisation, même à 20 ° C. Il est suggéré que les laits en poudre pour nourrissons / bébés formulés sur le marché nécessitent un stockage à basse température (4 ° C) ou à faible teneur en oxygène ( atmosphère N 2) afin de réduire les effets des réactions de Maillard (génération de rougeurs).

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