Green Tea (Camellia sinensis) Extract Induces p53-Mediated Cytotoxicity and Inhibits Migration of Breast Cancer Cells.

Green tea (GT) has been shown to play an important role in cancer chemoprevention. However, the related molecular mechanisms need to be further explored, especially regarding the use of GT extract (GTE) from the food matrix. For this study, epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were identified in GTE, representing 42 and 40% of the total polyphenols, respectively. MDA-MB-231 (p53-p.R280K mutant) and MCF-7 (wild-type p53) breast tumor cells and MCF-10A non-tumoral cells were exposed to GTE for 24-48 h and cell viability was assessed in the presence of p53 inhibitor pifithrin-α. GTE selectively targeted breast tumor cells without cytotoxic effect on non-tumoral cells and p53 inhibition led to an increase in viable cells, especially in MCF-7, suggesting the involvement of p53 in GTE-induced cytotoxicity. GTE was also effective in reducing MCF-7 and MDA-MD-231 cell migration by 30 and 50%, respectively. An increment in p53 and p21 expression stimulated by GTE was observed in MCF-7, and the opposite phenomenon was found in MDA-MB-231 cells, with a redistribution of mutant-p53 from the nucleus and no differences in p21 levels. All these findings provide insights into the action of GTE and support its anticarcinogenic potential on breast tumor cells.

Jaboticaba (Myrciaria jaboticaba) powder consumption improves the metabolic profile and regulates gut microbiome composition in high-fat diet-fed mice.

The consumption of a high-fat diet can cause metabolic syndrome and induces host gut microbial dysbiosis and non-alcoholic fatty liver disease (NAFLD). We evaluated the effect of polyphenol-rich jaboticaba peel and seed powder (JPSP) on the gut microbial community composition and liver health in a mouse model of NAFLD. Three-month-old C57BL/6 J male mice, received either a control (C, 10% of lipids as energy, n = 16) or high-fat (HF, 50% of lipids as energy, n = 64) diet for nine weeks. The HF mice were randomly subdivided into four groups (n = 16 in each group), three of which (HF-J5, HF-J10, and HF-J15) were supplemented with dietary JPSP for four weeks (5%, 10%, and 15%, respectively). In addition to attenuating weight gain, JPSP consumption improved dyslipidemia and insulin resistance. In a dose-dependent manner, JPSP consumption ameliorated the expression of hepatic lipogenesis genes (AMPK, SREBP-1, HGMCoA, and ABCG8). The effects on the microbial community structure were determined in all JPSP-supplemented groups; however, the HF-J10 and HF-J15 diets led to a drastic depletion in the species of numerous bacterial families (Bifidobacteriaceae, Mogibacteriaceae, Christensenellaceae, Clostridiaceae, Dehalobacteriaceae, Peptococcaceae, Peptostreptococcaceae, and Ruminococcaceae) compared to the HF diet, some of which represented a reversal of increases associated with HF. The Lachnospiraceae and Enterobacteriaceae families and the Parabacteroides, Sutterella, Allobaculum, and Akkermansia genera were enriched more in the HF-J10 and HF-J15 groups than in the HF group. In conclusion, JPSP consumption improved obesity-related metabolic profiles and had a strong impact on the microbial community structure, thereby reversing NAFLD and decreasing its severity.

Activation of Nrf2-Antioxidant Signaling by 1,25-Dihydroxycholecalciferol Prevents Leptin-Induced Oxidative Stress and Inflammation in Human Endothelial Cells.

Background: Obesity is associated with hyperleptinemia and endothelial dysfunction. Hyperleptinemia has been reported to induce both oxidative stress and inflammation by increasing reactive oxygen species production.Objective: The objective of this study was to determine the effects of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] against leptin-induced oxidative stress and inflammation in human endothelial cells.Methods: Small interfering RNA (siRNA) were used to knock down the expression of vitamin D receptor (VDR) in human umbilical vein endothelial cells (HUVECs). HUVECs were pretreated for 4 h with physiologic (10-10 M) or supraphysiologic (10-7 M) concentrations of 1,25(OH)2D3 and exposed to leptin (10 ng/mL). Superoxide anion production and translocation of nuclear factor (erythroid-derived 2)-like 2 (NRF2) and nuclear transcription factor κB (NF-κB) subunit p65 to the nucleus and the activation of their target genes were quantified.Results: Pretreatment of HUVECs with 1,25(OH)2D3 prevented the leptin-induced increase in superoxide anion production (P < 0.05). Pretreatment with 1,25(OH)2D3 further increased NRF2 translocation to the nucleus (by 3-fold; P < 0.05) and increased mRNA expression of superoxide dismutase 2 (SOD2; by 2-fold), glutathione peroxidase (GPX; by 3-fold), NAD(P)H dehydrogenase (quinone) 1 (NQO1; by 4-fold), and heme oxygenase 1 (HMOX1; by 2-fold) (P < 0.05). Leptin doubled the translocation of NF-κB (P < 0.05) to the nucleus and increased (P < 0.05) the upregulation of vascular inflammatory mediators such as monocyte chemoattractant protein 1 (MCP1; by 1-fold), transforming growth factor ß (TGF ß by 1-fold), and vascular cell adhesion molecule 1 (VCAM1; by 4-fold) (P < 0.05), which were prevented (P < 0.05) by pretreatment with 1,25(OH)2D3 Protective effects of 1,25(OH)2D3 were confirmed to be VDR dependent by using VDR siRNA.Conclusion: Pretreatment with 1,25(OH)2D3 in the presence of a high concentration of leptin has a beneficial effect on HUVECs through the regulation of mediators of antioxidant activity and inflammation.

Effects of proanthocyanidin on oxidative stress biomarkers and adipokines in army cadets: a placebo-controlled, double-blind study.

PURPOSE: The relatively recent advent of polyphenol supplement for exercise studies has been tested in a variety of forms and doses. However, the dose-response on adipokines and oxidative stress biomarker effect remains unknown. The aim of the present study was to assess the effect of intense, long-duration (48-h) exercise, and a single dose of proanthocyanidin, on plasma leptin, adiponectin, and electronegative low-density lipoprotein (LDL(-)) concentrations. METHODS: Fifty-four healthy male army cadets (22 ± 2 years) participated in a double-blind, randomized, placebo-controlled study and were distributed between control (CG; n = 27) and supplemented groups (SG; n = 27). Immediately before the start of the exercise, both CG and SG groups received a capsule containing starch (200 mg) or proanthocyanidin (dry Vitis vinifera extract, 200 mg), respectively. Following a 12-h fasting period, the plasma adiponectin, leptin, and LDL(-) concentrations were measured prior to the start of the exercise after 24 and 48 h of military training, and after 24 h of rest. The effects of the proanthocyanidin (supplement), exercise (time), and their interaction were investigated using factorial two-way ANOVA. RESULTS: Plasma leptin concentration was only influenced by exercise (p = 0.001). Plasma adiponectin concentration was influenced by exercise (p = 0.037), and by the exercise x supplement interaction (p = 0.033). LDL(-) was influenced by the supplement (p = 0.001), exercise (p = 0.001), and their interaction (p = 0.001). CONCLUSIONS: A single dose of proanthocyanidin (200 mg) was able to reduce LDL(-) concentration and increase plasma adiponectin concentration after 24 h of rest in SG group, indicating its potential protective action.

Effects of Resveratrol Supplementation in Nrf2 and NF-κB Expressions in Nondialyzed Chronic Kidney Disease Patients: A Randomized, Double-Blind, Placebo-Controlled, Crossover Clinical Trial.

INTRODUCTION: Resveratrol is a phenolic compound that has demonstrated anti-inflammatory and antioxidant effects, resulting from enhanced antioxidant enzymes production and modulating nuclear factors involved in the inflammation-oxidative stress cycle, as nuclear erythroid 2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB). OBJECTIVE: The study aim was to evaluate the effects of resveratrol supplementation on Nrf2 and NF-κB expression in nondialyzed chronic kidney disease (CKD) patients. MATERIALS AND METHODS: A randomized, double-blind, crossover trial was performed in 20 nondialyzed CKD patients (62.0 ± 8.0 years old, 45% men, body mass index of 27.7 ± 1.2 kg/m2, estimated glomerular filtration rate of 34.0 ± 13.0 mL/minute). Eleven patients were randomly allocated to "placebo first" (4 weeks placebo; 8 weeks washout, 4 weeks 500 mg of resveratrol/day) and 9 to "resveratrol first" (4 weeks 500 mg of resveratrol/day, 8 weeks washout, 4 weeks placebo). The peripheral blood mononuclear cells were isolated and processed for expression Nrf2 and NF-κB by quantitative real-time polymerase chain reaction. Proinflammatory cytokines and antioxidant enzymes were also measured. RESULTS: The effect size of Nrf2 supplementation (-0.13, P = .29) and NF-κB (0.09, P = .31) was not significant. There was no difference in proinflammatory biomarkers or antioxidant biomarkers after resveratrol supplementation. CONCLUSION: In this pilot study, 500 mg of resveratrol supplementation for 4 weeks had no antioxidant and anti-inflammatory effect in nondialyzed CKD patients. Additional studies with differing doses and/or time of treatment should be conducted to better elucidate the effects of the resveratrol supplementation in CKD patients.

Glucagon induces airway smooth muscle relaxation by nitric oxide and prostaglandin E2.

Glucagon is a hyperglycemic pancreatic hormone that has been shown to provide a beneficial effect against asthmatic bronchospasm. We investigated the role of this hormone on airway smooth muscle contraction and lung inflammation using both in vitro and in vivo approaches. The action of glucagon on mouse cholinergic tracheal contraction was studied in a conventional organ bath system, and its effect on airway obstruction was also investigated using the whole-body pletysmographic technique in mice. We also tested the effect of glucagon on lipopolysaccharide (LPS)-induced airway hyperreactivity (AHR) and inflammation. The expression of glucagon receptor (GcgR), CREB, phospho-CREB, nitric oxide synthase (NOS)-3, pNOS-3 and cyclooxygenase (COX)-1 was evaluated by western blot, while prostaglandin E2 (PGE2) and tumour necrosis factor-α were quantified by enzyme-linked immunoassay and ELISA respectively. Glucagon partially inhibited carbachol-induced tracheal contraction in a mechanism clearly sensitive to des-His1-[Glu9]-glucagon amide, a GcgR antagonist. Remarkably, GcgR was more expressed in the lung and trachea with intact epithelium than in the epithelium-denuded trachea. In addition, the glucagon-mediated impairment of carbachol-induced contraction was prevented by either removing epithelial cells or blocking NOS (L-NAME), COX (indomethacin) or COX-1 (SC-560). In contrast, inhibitors of either heme oxygenase or COX-2 were inactive. Intranasal instillation of glucagon inhibited methacholine-induced airway obstruction by a mechanism sensitive to pretreatment with L-NAME, indomethacin and SC-560. Glucagon induced CREB and NOS-3 phosphorylation and increased PGE2 levels in the lung tissue without altering COX-1 expression. Glucagon also inhibited LPS-induced AHR and bronchoalveolar inflammation. These findings suggest that glucagon possesses airway-relaxing properties that are mediated by epithelium-NOS-3-NO- and COX-1-PGE2-dependent mechanisms.

Systemic inflammation and oxidative stress in hemodialysis patients are associated with down-regulation of Nrf2.

BACKGROUND: Oxidative stress and inflammation are common features and the main mediators of progression of chronic kidney disease (CKD) and its cardiovascular complications. Under normal conditions, oxidative stress activates the transcription factor, nuclear factor E2-related factor 2 (Nrf2), which is the master regulator of genes encoding antioxidant and detoxifying enzymes and related proteins. The available data on expression of Nrf2 and its key target gene products in CKD patients is limited. We therefore investigated this topic in a group of CKD patients on hemodialysis. METHODS: Twenty adult hemodialysis (HD) patients (aged 54.9 ± 15.2 years) and 11 healthy individuals (aged 50.9 ± 8.0 years) were enrolled. Peripheral blood mononuclear cells (PBMC) were isolated and processed for expression of nuclear factor-κB (NF-κB), Nrf2, heme oxygenase-1 and NADPH: quinoneoxidoreductase 1 (NQO1) by quantitative real-time polymerase chain reaction and western blot analysis. Plasma malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α) levels were measured. RESULTS: Peripheral blood mononuclear cells from HD patients had significantly lower NQO1 and Nrf2 mRNA expressions (0.58 ± 0.35 vs. 1.13 ± 0.64, p = 0.005), and significantly higher NF-κB expression (2.18 ± 0.8 vs. 1.04 ± 0.22, p = 0.0001) compared to the healthy individuals. The NF-κB expression was inversely correlated with Nrf2 levels (r = -0.54, p < 0.01) in CKD patients. Plasma MDA and TNF-α levels were significantly higher in CKD patients than in the healthy individuals. CONCLUSIONS: Up-regulation of NFκB in the CKD patients' PBMC is coupled to down-regulation of Nrf2 and NQO1 expression. These observations are consistent with recent findings in CKD animals and point to the contribution of the impaired Nrf2 system in the pathogenesis of oxidative stress and inflammation in hemodialysis patients.

Nutritional strategies to modulate inflammation and oxidative stress pathways via activation of the master antioxidant switch Nrf2.

The nuclear factor E2-related factor 2 (Nrf2) plays an important role in cellular protection against cancer, renal, pulmonary, cardiovascular and neurodegenerative diseases where oxidative stress and inflammation are common conditions. The Nrf2 regulates the expression of detoxifying enzymes by recognizing the human Antioxidant Response Element (ARE) binding site and it can regulate antioxidant and anti-inflammatory cellular responses, playing an important protective role on the development of the diseases. Studies designed to investigate how effective Nrf2 activators or modulators are need to be initiated. Several recent studies have shown that nutritional compounds can modulate the activation of Nrf2-Keap1 system. This review aims to discuss some of the key nutritional compounds that promote the activation of Nrf2, which may have impact on the human health.

Suppression of hypoxia-inducible factor-1α contributes to the antiangiogenic activity of red propolis polyphenols in human endothelial cells.

Polyphenol-enriched fractions from natural sources have been proposed to interfere with angiogenesis in pathological conditions. We recently reported that red propolis polyphenols (RPP) exert antiangiogenic activity. However, molecular mechanisms of this activity remain unclear. Here, we aimed at characterizing molecular mechanisms to explain the impact of RPP on endothelial cells' (EC) physiology. We used in vitro and ex and in vivo models to test the hypothesis that RPP inhibit angiogenesis by affecting hypoxia-inducible factor-1α (HIF1α) stabilization in EC. RPP (10 mg/L) affected angiogenesis by reducing migration and sprouting of EC, attenuated the formation of new blood vessels, and decreased the differentiation of embryonic stem cells into CD31-positive cells. Moreover, RPP (10 mg/L) inhibited hypoxia- or dimethyloxallylglycine-induced mRNA and protein expression of the crucial angiogenesis promoter vascular endothelial growth factor (VEGF) in a time-dependent manner. Under hypoxic conditions, RPP at 10 mg/L, supplied for 1-4 h, decreased HIF1α protein accumulation, which in turn attenuated VEGF gene expression. In addition, RPP reduced the HIF1α protein half-life from ~58 min to 38 min under hypoxic conditions. The reduced HIF1α protein half-life was associated with an increase in the von Hippel-Lindau (pVHL)-dependent proteasomal degradation of HIF1α. RPP (10 mg/L, 4 h) downregulated Cdc42 protein expression. This caused a corresponding increase in pVHL protein levels and a subsequent degradation of HIF1α. In summary, we have elucidated the underlying mechanism for the antiangiogenic action of RPP, which attenuates HIF1α protein accumulation and signaling.

Efecto del propóleos chileno sobre el metabolismo de glucosa en ratones diabéticos / Effect of chilean propolis on glucose metabolism in diabetic mice

En el presente estudio se evaluó el efecto del propóleos sobre el metabolismo de la glucosa en ratones C57/BL-6 con diabetes mellitus tipo 2 inducida por dieta alta en grasa. Se midieron los cambios en las concentraciones séricas de lípidos, glucosa e insulina, y el efecto sobre la captación de 2-deoxi-[2,6-3H]-D-glucosa, síntesis de [14C]-glicógeno y descarboxilación de [U-14C]-D-glucosa inducida por insulina en músculo aislado. Los resultados muestran que en ratones diabéticos, el tratamiento con propóleos (150 mg/kg/día) reduce los niveles de insulina e índice HOMA (P<0.05). También disminuyó la obesidad abdominal de estos animales (P<0.05). Por otro lado, no modificó las concentraciones plasmáticas de glucosa, colesterol total y triglicéridos. Se observó también que la captación de 2-deoxi-[2,6-3H]-D-glucosa, síntesis de [14C]-glicógeno y descarboxilación de [U-14C]-D-glucosa inducida por insulina en músculo sóleo de ratones tratados con propóleos fue significativamente superior al grupo control (P<0.05). En resumen, nuestros datos confirman que el propóleos es capaz de modular el metabolismo de glucosa en ratones C57/BL-6 con diabetes mellitus tipo 2 inducida por dieta alta en grasa. Los datos obtenidos constituyen un importante antecedente que avala el posible uso del propóleos como fuente de polifenoles con actividad antidiabetogénica.

In the current study, we investigated the effect of propolis on diabetic mice undergoing propolis treatment (150 mg/kg/day) for a 6 week period. We also evaluated serum lipids, glucose, insulin levels and the effect on glucose uptake of 2-deoxy-D-[2,6-3H] glucose, [14C]-glycogen synthesis and [U-14C]-D-glucose decarboxylation induced by insulin in muscle tissue. Our results show that treatment with propolis (150 mg/kg/day) reduced insulin and HOMA index (P<0.05). Propolis also lowered abdominal obesity (P<0.05). No effects over serum glucose, total cholesterol and triglycerides levels were observed. We also observed that uptake of 2-deoxy-D-[2,6-3H] glucose, [14C]-glycogen synthesis and [U-14C]-D-glucose decarboxylation induced by insulin in soleus muscle of mice treated with propolis were significantly greater than control group (P<0.05). In summary, our data establishes that propolis modulates glucose metabolism. This result constitutes important data indicating that propolis can be used as a polyphenols source with antidiabetogenic activity.