Polyphenols and aging

3-(2,4-dimethoxybenzylidene)-anabaseine: a promising candidate drug for Alzheimer's disease?

3-(2,4-dimethoxybenzylidene)-anabaseine is an analog of the paralytic alkaloid, anabaseine, from the ribbon worms Amphiporus sp., that shows numerous properties, in particular an agonist activity on alpha 7 nicotinic acetylcholine receptors. This article reviews these properties and explains to what extent they could be valuable to control symptomatology and/or neurodegeneration in Alzheimer's disease.

Natural polyphenols in cancer therapy

Natural polyphenols are secondary metabolites of plants involved in defense against different types of stress. Extracts containing these compounds have been used for thousands of years in traditional eastern medicine. Polyphenols act on multiple targets in pathways and mechanisms related to carcinogenesis, tumor cell proliferation and death, inflammation, metastatic spread, angiogenesis, or drug and radiation resistance. Nevertheless, reported effects claimed for polyphenols are controversial, since correlations between in vitro effects and in vivo evidence are poorly established. The main discrepancy between health claims versus clinical observations is the frequent use of nonphysiologically relevant concentrations of these compounds and their metabolites in efficacy and mechanistic studies. The present review will discuss how in vivo administration correlates with polyphenol metabolism, toxicity, and bioavailability. Analysis of the general application of polyphenols in cancer therapy will be complemented by potential applications in the therapy of specific tumors, including melanoma, colorectal and lung cancers. Possible pharmaceutical formulations, structural modifications, combinations, and delivery systems aimed to increase bioavailability and/or biological effects will be discussed. Final remarks will include recommendations for future research and developments.

Potential applications of curcumin and its novel synthetic analogs and nanotechnology-based formulations in cancer prevention and therapy

Curcumin has attracted great attention in the therapeutic arsenal in clinical oncology due to its chemopreventive, antitumoral, radiosensibilizing and chemosensibilizing activities against various types of aggressive and recurrent cancers. These malignancies include leukemias, lymphomas, multiple myeloma, brain cancer, melanoma and skin, lung, prostate, breast, ovarian, liver, gastrointestinal, pancreatic and colorectal epithelial cancers. Curcumin mediates its anti-proliferative, anti-invasive and apoptotic effects on cancer cells, including cancer stem/progenitor cells and their progenies, through multiple molecular mechanisms. The oncogenic pathways inhibited by curcumin encompass the members of epidermal growth factor receptors (EGFR and erbB2), sonic hedgehog (SHH)/GLIs and Wnt/β-catenin and downstream signaling elements such as Akt, nuclear factor-kappa B (NF-κB) and signal transducers and activators of transcription (STATs). In counterbalance, the high metabolic instability and poor systemic bioavailability of curcumin limit its therapeutic efficacy in human. Of great therapeutic interest, the selective delivery of synthetic analogs or nanotechnology-based formulations of curcumin to tumors, alone or in combination with other anticancer drugs, may improve their chemopreventive and chemotherapeutic efficacies against cancer progression and relapse. Novel curcumin formulations may also be used to reverse drug resistance, eradicate the total cancer cell mass and improve the anticarcinogenic efficacy of the current anti-hormonal and chemotherapeutic treatments for patients with various aggressive and lethal cancers.

Down regulation effect of Rosmarinus officinalis polyphenols on cellular stress proteins in rat pheochromocytoma PC12 cells

Polyphenols are known to exhibit wide spectrum of benefit for brain health and to protect from several neurodegenerative diseases. The present study was sought to determine the neuroprotective effects of Rosmarinus officinalis' polyphenols (luteolin, carnosic acid, and rosmarinic acid) through the investigation of stress-related proteins. We carried out measurement of the expression of heat-shock protein (Hsp) 47 promoter in heat stressed Chinese hamster ovary transfected cells. We performed proteomic analysis and confirmed gene expression by real time PCR in PC12 cells. Results showed that these compounds modulated significant and different effects on the expression of 4 stress-related proteins: heat shock protein 90 α (Hsp90), Transitional endoplasmic reticulum ATPase (VCP/p97), Nucleoside diphosphate kinase (NDK), and Hypoxia up-regulated protein 1 (HYOU1)) at translational and post translational levels in PC12 cells and they downregulated the expression of Hsp47 activity in Chinese hamster transformed cells. These findings suggest that luteolin, carnosic acid, and rosmarinic acid may modulate the neuroprotective defense system against cellular stress insults and increase neuro-thermotolerance.

Effects of long-term consumption of low doses of resveratrol on diet-induced mild hypercholesterolemia in pigs: a transcriptomic approach to disease prevention

Metabolic and cardiovascular diseases (CVDs) have risen to alarming proportions, and there is a need for therapeutic and preventive measures. The polyphenol resveratrol (RES) protects against CVDs, but in vivo molecular mechanisms responsible for protection are not yet understood. Peripheral blood mononuclear cells (PBMNCs) are involved in the development of atherosclerosis and metabolic disorders. The identification of PBMNCs genes responding to dietary compounds might help to understand the mechanisms underlying the effects of polyphenols. We determined gene expression differences between PBMNCs from pigs fed a high-fat diet manifesting a mild increase of cholesterol and pigs fed a high-fat diet containing low doses of RES. Although the consumption of RES did not modify the levels of cholesterol, microarray analyses indicated that some of the differentially expressed genes, collagens (COL1A, COL3A), lipoprotein lipase (LPL) and fatty-acid binding proteins (FABPs) involved in CVDs and lipid metabolism were up-regulated by the high-fat diet and down-regulated by RES. Reverse transcriptase polymerase chain reaction confirmed that RES and RES-containing grape extract prevented the induction of FABP4 in PBMNCs in female pigs fed a high-fat diet. Low micromolar concentrations of RES and its metabolite dihydroresveratrol exerted a minor but significant reducing effect on the induction of FABP4 expression in human macrophages treated with oxidized low-density lipoprotein. Our results show that the consumption of low doses of RES modulates the expression of genes related to lipid metabolism and metabolic disorders that are affected by a high-fat diet and suggest that some of the circulating RES metabolites may contribute to these effects.

Non-antibacterial tetracyclines modulate mediators of periodontitis and atherosclerotic cardiovascular disease: a mechanistic link between local and systemic inflammation

Periodontitis, one of the most common chronic inflammatory diseases afflicting man, is increasingly being recognized as a risk factor for atherosclerotic cardiovascular disease (ASCVD). Non-antimicrobial tetracyclines are known to have inhibitory effects on inflammatory mediators and effector molecules, including cytokines and matrix metalloproteinases (MMPs), associated with both diseases. In this paper, we discuss the evidence that doxycycline and related non-antibiotic chemically modified tetracyclines (e.g., CMT-3) can effectively reduce cytokine (TNF-α, IL-6, and MCP-1) production by human mononuclear inflammatory cells when stimulated either by endotoxin (LPS) or by a complex of C-reactive protein/oxidized LDL cholesterol relevant to the pathogenesis of periodontal disease and ASCVD, respectively. This inhibition by tetracycline compounds appears to be mediated at least in part by a suppression of the phosphorylation/activation of the NFκB cell signaling pathway. We are currently conducting clinical trials on patients who exhibit both diseases, and our preliminary data suggest that virtually all acute coronary syndrome (ACS) patients exhibit moderate-to-severe periodontitis, a higher incidence of this oral inflammatory disease than that seen in the population at large. In other studies, a non-antimicrobial formulation of doxycycline (SDD) has been found to dramatically reduce hsCRP, IL-6 and MMP-9 levels in plasma of ACS patients, and SDD has also been found to significantly increase serum levels of both cardio-protective HDL cholesterol and its core molecule apolipoprotein A-I in ASCVD-vulnerable patients with periodontitis. Our current research suggests that one mechanism involved may be the ability of SDD to inhibit MMP-mediated HDL loss by protecting apolipoprotein A-I from proteinase attack. These pleiotropic mechanisms of non-antimicrobial tetracyclines provide significant therapeutic potential to treat chronic inflammatory diseases including both periodontitis and ASCVD.

The herbal preparation Padma® 28 protects against neurotoxicity in PC12 cells

Padma® 28 is a multicompound herbal preparation based on the camphor formulas from traditional Tibetan medicine (TTM). It contains a variety of different secondary plant substances, which include terpenes and polyphenols such as flavonoids and tannins. As a rich source of antioxidant polyphenols, this herbal Padma 28 preparation seems to be a promising candidate for the treatment of degenerative diseases such as Alzheimer's disease (AD), a condition involving oxidative stress. Moreover, polyphenols have also been shown to mitigate AD neuropathology. The study investigated the protective effect of Padma 28 and of certain polyphenols on the neurotoxicity of PC12 cells induced by the neurotoxins: amyloid-beta (Aβ), glutamate, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 3-nitropropionate (3-NP), known to be involved in AD, Parkinson's disease (PD), amyotrophic-lateral-sclerosis (ALS) and Huntington's disease (HD), respectively. The decrease in cell viability induced by each of the toxins was significantly attenuated by Padma 28 treatment. Also, a decrease in the oxidative capacity of PC12 cells treated with Padma 28 was noted, indicating that the decrease in cell viability induced by the toxins might have been the result of an oxidative stress which could be attenuated by Padma 28 acting as a potent antioxidant. Padma 28, which is available in Europe and USA, seems to be a promising candidate for the treatment of CNS diseases.

Resveratrol and cellular mechanisms of cancer prevention

The use of novel and improved chemopreventive and chemotherapeutic agents for the prevention and treatment of cancer is on the rise. Natural products have always afforded a rich source of such agents. Epidemiological evidence suggests that a higher flavonoid intake is associated with low cancer risk. Accumulating data clearly indicate that the induction of apoptosis is an important component in the chemoprevention of cancer by naturally occurring dietary agents. Resveratrol, a naturally occurring polyphenol, demonstrates pleiotropic health benefits, including antioxidant, anti-inflammatory, antiaging, cardioprotective, and neuroprotective activities. Because of these properties and their wide distribution throughout the plant kingdom, resveratrol is envisioned as a potential chemopreventive/curative agent. Currently, a number of preclinical findings from our lab and elsewhere suggest resveratrol to be a promising natural weapon in the war against cancer. Remarkable progress in elucidating the molecular mechanisms underlying the anticancer properties of resveratrol has been achieved. Here, we focus on some of the myriad pathways that resveratrol targets to exert its chemopreventive role and advocate that resveratrol holds tremendous potential as an efficient anticancer drug of the future.

Nutrition and human health from a sex-gender perspective

Nutrition exerts a life-long impact on human health, and the interaction between nutrition and health has been known for centuries. The recent literature has suggested that nutrition could differently influence the health of male and female individuals. Until the last decade of the 20th century, research on women has been neglected, and the results obtained in men have been directly translated to women in both the medicine and nutrition fields. Consequently, most modern guidelines are based on studies predominantly conducted on men. However, there are many sex-gender differences that are the result of multifactorial inputs, including gene repertoires, sex steroid hormones, and environmental factors (e.g., food components). The effects of these different inputs in male and female physiology will be different in different periods of ontogenetic development as well as during pregnancy and the ovarian cycle in females, which are also age dependent. As a result, different strategies have evolved to maintain male and female body homeostasis, which, in turn, implies that there are important differences in the bioavailability, metabolism, distribution, and elimination of foods and beverages in males and females. This article will review some of these differences underlying the impact of food components on the risk of developing diseases from a sex-gender perspective.

Effect of oral resveratrol on the BDNF gene expression in the hippocampus of the rat brain

Resveratrol is a plant polyphenolic compound. Evidence indicates that resveratrol has beneficial effects against aging and neurodegenerative diseases. The goal of our study was in vivo examination of the effects of resveratrol on the abundance of mRNA encoding Brain Derived Neurotrophic Factor (BDNF) in the hippocampus of rat brain. Rats were administrated orally by different doses (2.5-20 mg/kg bwt) of resveratrol for 3, 10 and 30 days. Saline was used as control and 10% ethanol in saline was used as vehicle for resveratrol. Measurement of BDNF mRNA by Real-time RT-PCR showed that levels of the mRNA for BDNF were significantly and dose dependently elevated in the hippocampal tissues of rats. The findings suggest that the neuroprotective effects of resveratrol may be at least partly due to its inducing effects on the expression levels of the BDNF mRNA.

Improvement of leucocyte functions in mature and old mice after 15 and 30 weeks of diet supplementation with polyphenol-rich biscuits

PURPOSE

To study the effect of diet supplementation with polyphenols on several functions suffering age-related changes, in peritoneal leucocytes from mature and old mice.

METHODS

Five groups of female ICR mice were used. Four groups received a supplementation (20% wt/wt) of biscuits with different cereal fractions naturally rich in polyphenols (named CO49, CO50, CO52, CO53), containing different amounts of catechin, p-hydroxybenzoic acid, vanillic acid, p-coumaric acid, sinapic acid, ferulic acid, rutin and oryzanol. The control group received only standard maintenance diet. Peritoneal suspensions were obtained after 15 and 30 weeks of diet supplementation, when the age of the animals was 49 ± 2 (mature mice) and 64 ± 2 weeks (old mice), respectively. The functions analysed were: chemotaxis of macrophages and lymphocytes, phagocytosis of particles by macrophages, intracellular superoxide anion levels, lymphoproliferative response to mitogens (concanavalin A and lipopolysaccharide), interleukin-2 secretion and natural killer (NK) activity, as functions that decrease with age, and adherence of macrophages and lymphocytes and tumour necrosis factor-α secretion as functions with age-related increase.

RESULTS

The supplementation, in general, increased the functions that decrease with age and decreased those that increase with age. There were differences in the effects shown by the four kinds of biscuits depending on the function studied and the number of weeks of supplementation.

CONCLUSION

Since the immune system has been proposed as a good marker of health and predictor of longevity, diet supplementation with cereals naturally rich in polyphenols could be an important way for health preservation with age and reaching high longevity.

Resveratrol enhances antitumor activity of TRAIL in prostate cancer xenografts through activation of FOXO transcription factor

BACKGROUND

Resveratrol (3, 4', 5 tri-hydroxystilbene), a naturally occurring polyphenol, exhibits anti-inflammatory, antioxidant, cardioprotective and antitumor activities. We have recently shown that resveratrol can enhance the apoptosis-inducing potential of TRAIL in prostate cancer cells through multiple mechanisms in vitro. Therefore, the present study was designed to validate whether resveratrol can enhance the apoptosis-inducing potential of TRAIL in a xenograft model of prostate cancer.

METHODOLOGY/PRINCIPAL FINDINGS

Resveratrol and TRAIL alone inhibited growth of PC-3 xenografts in nude mice by inhibiting tumor cell proliferation (PCNA and Ki67 staining) and inducing apoptosis (TUNEL staining). The combination of resveratrol and TRAIL was more effective in inhibiting tumor growth than single agent alone. In xenografted tumors, resveratrol upregulated the expressions of TRAIL-R1/DR4, TRAIL-R2/DR5, Bax and p27(/KIP1), and inhibited the expression of Bcl-2 and cyclin D1. Treatment of mice with resveratrol and TRAIL alone inhibited angiogenesis (as demonstrated by reduced number of blood vessels, and VEGF and VEGFR2 positive cells) and markers of metastasis (MMP-2 and MMP-9). The combination of resveratrol with TRAIL further inhibited number of blood vessels in tumors, and circulating endothelial growth factor receptor 2-positive endothelial cells than single agent alone. Furthermore, resveratrol inhibited the cytoplasmic phosphorylation of FKHRL1 resulting in its enhanced activation as demonstrated by increased DNA binding activity.

CONCLUSIONS/SIGNIFICANCE

These data suggest that resveratrol can enhance the apoptosis-inducing potential of TRAIL by activating FKHRL1 and its target genes. The ability of resveratrol to inhibit tumor growth, metastasis and angiogenesis, and enhance the therapeutic potential of TRAIL suggests that resveratrol alone or in combination with TRAIL can be used for the management of prostate cancer.