Grape Powder Research Articles

Polyphenols Extracted From Grape Powder Induce Lipogenesis and Glucose Uptake During Differentiation of Murine 3T3‐F442A Preadipocytes

Assessing the effect of dietary ingredients on lipogenesis and glucose uptake in adipocytes may clarify the risk/benefit of recommending to individuals with obesity and insulin resistance. Grape powder extracted polyphenols (GPEP) modulate inflammation in human adipocytes. We hypothesized that GPEP increase intracellular fat accumulation and glucose uptake during differentiation of 3T3‐F442A preadipocytes. Total polyphenols were extracted and measured based on gallic acid equivalents (GAE). There were 2167 mg of GAE of polyphenols in 100 g of grape powder (GP). 3T3‐F442A cells were incubated with GPEP from 125 – 500 µg GP/mL of media until day 8 of differentiation when the cells were collected for different assays. Adipo‐Red assay and Oil Red O staining showed that GPEP induced, in a dose‐dependent manner, an increase in intracellular triglyceride content of adipocytes. Concomitantly, GPEP increased, in a dose‐dependent manner, glucose uptake by 3T3‐F442A cells. No changes in cell viability were measured by Trypan blue staining, suggesting that these effects were independent of cytotoxicity. Western‐blot showed that GPEP upregulated total and membrane protein level of GLUT4 in 3T3‐F442A adipocytes. Ly294002 (10 µmol/L), a phosphatidyl‐inositol 3 kinase (PI3K) inhibitor, reversed the effects of GPEP on cellular lipid content. Real‐time qPCR showed that GPEP increased mRNA expression of fatty acid synthase, lipoprotein lipase, and adiponectin, while it decreased mRNA expression of leptin and insig‐1. Our results indicate that GPEP may induce adipocyte differentiation via upregulation of GLUT4, PI3K and adipogenic genes.

Effects of Chronic and Acute Grape Consumption on Gene Expression of Inflammatory Mediators in PBMC

Studies have demonstrated that polyphenol‐rich foods offer protection against chronic metabolic diseases caused by inflammation and oxidative stress. We investigated whether consumption of grapes alters expression of inflammatory pathway genes and transcription factors in a chronic and acute setting. In this double‐blind, crossover trial, 20 obese subjects (BMI 37.0 ± 9.9) were randomized to consume either 60 g of freeze‐dried whole grape powder (Grape) daily (297 mg polyphenols) or matched placebo (C) daily (0 mg polyphenols) for 4 weeks separated by a 2‐week washout. Acute study days at the beginning of each intervention consisted of a high fat, high carbohydrate meal challenge (1,036 kcal, 31 g protein, 107 g carbohydrate, 54 g fat) accompanied by Grape or C consumption. Peripheral blood mononuclear cells (PBMCs) were isolated from fasted blood on acute study days and at postprandial time points 1, 3, and 5 hr. Fasted blood PBMCs were isolated at the end of each chronic, 4‐week intervention. Gene expression was assessed using real‐time quantitative PCR. Relative expression levels of target genes were calculated using the comparative CT method following normalization to the endogenous reference gene GAPDH. Expression of TNFα, NF‐κB, and IκBα genes in PBMCs shows no significant differences for Grape vs. C after 4 weeks of chronic consumption. Preliminary data examining expression of the same genes in the acute setting are inconclusive. Initial results indicate that grape consumption does not impact gene expression in inflammatory pathways; however additional genes must be investigated. (Supported by the California Table Grape Commission and USDA CRIS CA‐S*‐NTR‐6316‐H)

Effect of Grape Consumption on Biomarkers of Endothelial and Cardiovascular Health

Polyphenols have been associated with cardio‐protective benefits, however causal mechanisms remain elusive. This randomized, double‐blind, crossover study examines acute and longer‐term effects of grape consumption on biomarkers of endothelial and cardiovascular health. It was hypothesized that polyphenol‐rich grape consumption would protect against diet‐induced elevations and long‐term impairment in biomarkers of endothelial dysfunction during the acute postprandial period and after 4 weeks respectively. Twenty obese (BMI 37.0±9.9) but otherwise healthy adults were provided with isocaloric sachets of freeze‐dried whole grape powder (grape) (1 60g sachet/day=297mg polyphenol) and placebo (1 60g sachet/day=0mg polyphenol) for daily consumption, each treatment for 4 weeks separated by 2 week washout. To examine acute effects, postprandial blood samples were collected at 0, 1, 3 and 5 hours following a high fat high carbohydrate (HFHC) meal challenge and grape or placebo consumption. Longer‐term effects were examined by fasted blood samples collected on the last day of each 4‐week intervention. HDL increased (p<0.05) after 4 week grape consumption, but no other significant changes in lipids or blood glucose were noted between groups. Data analyzed by repeated measures, 2‐way ANOVA, showed that PAI‐1 and MCP‐1 were significantly elevated in plasma after HFHC challenge (p<0.05). However, no significant differences in plasma sICAM, sVCAM, ET‐1, PAI‐1 or MCP‐1 were detected between grape and placebo treatments after HFHC challenge or 4‐week intervention. Grape consumption has some beneficial effects on markers of cardiovascular health.Supported by California Table Grape Commission and USDA CRIS CA‐S*‐NTR‐6316‐H

Evaluation of protective effect of freeze-dried strawberry, grape, and blueberry powder on acrylamide toxicity in mice.

Berries are dietary plants with high antioxidant activity. The aim of this study is to investigate the protective effect of berries (strawberry, grape, and blueberry) against the acrylamide (AA)-induced general toxicity, genotoxicity, and reproductive toxicity in mice model, respectively. Mice were treated with 50 mg/kg b.w./day AA intraperitoneal injection for 5 d after feeding control diet or diet containing freeze-dried strawberry, grape, and blueberry powder. The results showed that AA induced a significant general toxicity, genotoxicity, and reproductive toxicity in mice. Compared with the control diet, the diets containing berries could reverse the AA-induced alterations in liver antioxidant enzymes activities (P < 0.05). Moreover, the AA-induced genotoxicity could be prevented by the diet containing berries. The DNA damage in the lymphocyte and liver cells and the micronucleus formation in bone marrow cell were significantly alleviated (P < 0.05). Meanwhile, the mice fed with diets containing berries showed a recovery in the sperm count, the sperm activity rate, sperm motility parameters, and the abnormal sperm rate (P < 0.05). Berry powders have remarkable intervention against the AA-induced general toxicity, genotoxicity, reproductive toxicity. Abundant phenolics, especially anthocyanins, may contribute to the intervention.

머루 분말을 첨가한 샐러드드레싱의 저장 중 품질 특성과 항산화 활성

This study evaluated the quality characteristics and antioxidant activities of salad dressings prepared with wild grape powder (1%, 2%, 3%, and 5%) during storage at 5°C for 4 weeks as well as sensory evaluation. The viscosity and pH decreased with increasing amounts of wild grape powder as well as increasing storage time. Moisture contents significantly decreased with increasing amounts of wild grape powder. The water activity of the control was higher than other samples at 0.924 Aw. The samples with wild grape powder showed lower water activities than the control at 0.902∼0.912 Aw after 4 weeks. For color, lightness and yellowness significantly decreased with increasing amounts of wild grape powder, whereas redness increased. Antioxidant activity, total polyphenol content, DPPH radical scavenging activity, and ABTS radical scavenging activity significantly increased with increasing amounts of wild grape powder but decreased with increasing storage time. In the sensory evaluation, the color preference was highest in the control. Flavor and texture preference were highest in the 2% sample. For overall acceptability, the 1% sample scored 5.71, which was highest among the samples. Based on the above study results, the optimum level of wild grape powder for production of salad dressing is 2%.

A Grape-Enriched Diet Increases Bone Calcium Retention and Cortical Bone Properties in Ovariectomized Rats1–3

Grapes and their associated phytochemicals have been investigated for beneficial effects on cardiovascular health, cancer prevention, and other chronic diseases, but the effect of grape consumption on bone health has not been fully determined. We previously found short-term benefits of grape products on reducing bone turnover in ovariectomized rats. The objective of this study was to determine the long-term benefits of a grape-enriched diet on bone in ovariectomized rats. Rats were ovariectomized at 3 mo of age and were administered a single dose of (45)Ca to prelabel bones at 4 mo of age. After a 1-mo equilibration period, baseline urinary (45)Ca excretion was determined. Rats (n = 22/group) were then randomly assigned to a modified AIN93M diet containing 25% freeze-dried grape powder or to a control diet for 8 wk. Urinary (45)Ca excretion was monitored throughout the study to determine changes in bone (45)Ca retention. Calcium balance was assessed after 1 and 8 wk of consuming the experimental diets, and a calcium kinetic study was performed at 8 wk. After 8 wk, femurs were collected for micro-computed tomographic imaging, 3-point bending, and reference point indentation. Rats fed the grape-enriched diet had 44% greater net bone calcium retention than did rats fed the control diet. There were no differences in calcium balance due to diet at either week 1 or week 8, but there was a significant increase in net calcium absorption (10.6%) and retention (5.7%) from week 1 to week 8 in the grape-enriched diet group only. Grape-enriched diet-fed rats had 3% greater cortical thickness and 11% greater breaking strength. There were no differences in femur bone mineral density, trabecular microarchitecture, or reference point indentation variables due to diet. This study of ovariectomized rats indicates that the consumption of grape products may improve calcium utilization and suppress bone turnover, resulting in improvements in bone quality.

머루 분말로 대체한 쌀 시폰 케이크의 품질과 항산화 활성

머루 분말 3%, 6%, 9% 및 12% 대체량을 달리한 쌀 시폰 케이크를 제조하고 이의 품질 특성, 항산화 특성 및 관능검사를 실시하였다. 대조군의 비중은 0.48 g/mL로 가장 높았으며 머루 분말 대체량이 증가할수록 유의적으로 낮아졌으며(P<0.05), 점도는 대조군이 11,606 cp로 유의적으로 가장 높았고(P<0.05) 머루 분말 대체량이 증가할수록 낮아지는 경향을 보였다. 반죽과 케이크의 pH는 대조군이 각각 5.77, 5.87로 가장 높았으며 머루 분말 대체량이 증가할수록 유의적으로 낮아졌으며(P<0.05), 총산도는 유의적으로 증가하였다(P<0.05). 수분함량은 머루 분말 대체량이 증가할수록 유의적으로 높아졌고(P<0.05), 수분활성도는 0.905~0.908로 유의적인 차이를 나타내지 않았다(P<0.05). 색도에서 명도와 황색도는 머루 분말 대체량이 증가할수록 유의적으로 낮아졌고(P<0.05), 적색도는 유의적으로 높아졌다(P<0.05). 조직감은 경도, 부서짐성, 검성 및 씹힘성은 머루 분말 대체량이 증가할수록 유의적으로 높아졌고(P<0.05) 부착성은 유의적인 차이를 보이지 않았으며, 응집성과 복원성은 6% 대체군이 가장 높게 나타났다. 총 폴리페놀 함량, DPPH, ABTS 라디칼 소거활성은 머루 분말 대체량이 증가할수록 유의적으로 높아졌다(P<0.05). 관능검사에서 색, 향미, 부드러운 정도 및 전체적인 기호도는 대조군이 가장 높았으며 머루 분말 대체량이 증가할수록 낮아지는 경향을 나타내었다. 따라서 시폰 케이크의 품질 특성, 관능검사 및 항산화 효과 등을 고려할 때 머루 분말 6% 대체한 쌀 시폰 케이크가 가장 적절한 것으로 사료되었다. 또한 머루를 이용한 다양한 가공식품의 확대를 위해 머루로 대체한 쌀 시폰 케이크의 저장성에 미치는 영향 등에 대한 추후 연구가 필요할 것으로 생각된다.

Grape powder prevents cognitive, behavioral, and biochemical impairments in a rat model of posttraumatic stress disorder

Previously, using the single-prolonged stress (SPS) rat model of posttraumatic stress disorder, we reported that moderate treadmill exercise, via modulation of oxidative stress-related mechanisms, rescued anxiety- and depression-like behaviors and reversed SPS-induced memory impairment. In this study using the SPS model (2-hour restrain, 20-minute forced swimming, 15-minute rest, and 1-2–minute diethyl ether exposure), we hypothesized that antioxidant rich grape powder (GP) prevents SPS-induced behavioral and memory impairment in rats. Male Sprague Dawley rats were randomly assigned into control (CON) (provided tap water), SPS (provided tap water), GP-SPS (provided 15 g/L GP in tap water for 3 weeks followed by SPS), or GP-CON (3 weeks of GP followed by CON exposure). Anxiety- and depression-like behaviors were significantly greater in SPS rats, when compared with CON- or GP-treated rats, and GP reversed these behavioral deficits. Single-prolonged stress rats made significantly more errors in both short- and long-term memory tests compared with CON- or GP-treated rats, which were prevented in GP-SPS rats. Grape powder prevented SPS-induced increase in plasma corticosterone level. Furthermore, brain-derived neurotrophic factor levels were significantly decreased in amygdala of SPS rats but not in GP-SPS rats compared with CON or GP-CON rats. In addition, GP significantly increased acetylated histone 3 and histone deacetylase 5 in hippocampus and amygdala of SPS rats as compared with CON or GP-CON rats. In conclusion, we suggest protective role of GP in SPS-induced behavioral, cognitive, and biochemical impairments in rats. Perhaps, epigenetic regulation of brain-derived neurotrophic factor enables GP-mediated prevention of SPS-induced deficits in rats.

The sustained delivery of resveratrol or a defined grape powder inhibits new blood vessel formation in a mouse model of choroidal neovascularization.

The objective of this study was to determine whether resveratrol or a defined, reconstituted grape powder can attenuate the formation of new blood vessels in a mouse model of choroidal neovascularization (CNV). To accomplish this objective, C57BL/6J mice were randomized into control or treatment groups which received either resveratrol or grape powder by daily oral gavage, resveratrol or grape powder delivered ad libitum through the drinking water, or resveratrol by slow release via implanted osmotic pumps. A laser was used to rupture Bruch’s membrane to induce CNV which was then detected in sclerochoroidal eyecups stained with antibodies against intercellular adhesion molecule-2. CNV area was measured using fluorescence microscopy and Image J software. Ad libitum delivery of both resveratrol and grape powder was shown to significantly reduce the extent of CNV by 68% and 57%, respectively. Parallel experiments conducted in vitro demonstrated that resveratrol activates p53 and inactivates Akt/protein kinase B in choroidal endothelial cells, contributing to its anti-proliferative and anti-migratory properties. In addition resveratrol was shown to inhibit the formation of endothelial cell networks, augmenting its overall anti-angiogenic effects. The non-toxic nature of resveratrol makes it an especially attractive candidate for the prevention and/or treatment of CNV.

Evaluation of the Aromatase Inhibition Potential of Freeze-Dried Grape Powder

ABSTRACTObjective: To determine the role of freeze-dried grapes as a potential aromatase inhibitor by testing of plasma hormone levels. Methods: A six-week study was conducted involving postmenopausal women during which 94 g of freeze-dried grape powder was consumed in addition to their usual diet. Plasma hormones were measured before and after the treatment. Results: Of the 18 women involved in the study, average age and body mass index were 61.4 years and 24.4 respectively. For the hormone levels studied, the following median (interquartile range) percentage changes from baseline to six-week values were found: estradiol +11.8% (−34.4%, +44.2%), p = .42; estrone +3.4% (−15.7%, +12.9%), p = .64; estrone sulfate +5.3% (−19.9%, +56.3%), p = .35; testosterone −1.5% (−14.7%, +10.7%), p = .97; and androstenedione +12.6% (−17.1%, +49.1%), p = .15. The hormone levels did not significantly change between baseline and six weeks. Further, the changes that were observed did not tend to go in the hypothesized direction (estrogens and conjugates increased slightly, and testosterone decreased slightly). Only androstenedione showed a trend toward change in the hypothesized direction. Conclusions: In this study, there was no evidence that plasma hormone levels are altered by six weeks of daily consumption of 94 g of freeze-dried grape powder.

Freeze-Dried Grape Powder Reduces Joint Pain and Influences Serum Cartilage and Inflammatory Biomarkers in Older Adults with Self-Reported Knee Osteoarthritis

Freeze-Dried Grape Powder Reduces Joint Pain and Influences Serum Cartilage and Inflammatory Biomarkers in Older Adults with Self-Reported Knee Osteoarthritis

Dietary grape powder increases IL-1β and IL-6 production by lipopolysaccharide-activated monocytes and reduces plasma concentrations of large LDL and large LDL-cholesterol particles in obese humans.

Obese individuals are at an increased risk of developing CVD, hypertension, type 2 diabetes, and bacterial and viral infections when compared with the normal-weight population. In a 9-week randomised, double-blind, cross-over study, twenty-four obese subjects aged between 20 and 60 years and with a BMI between 30 and 45 kg/m2 were fed grape or placebo powder for 3-week intervals to determine the effects of dietary grapes on blood lipid profiles, plasma inflammatory marker concentrations and immune cell function. Blood samples were collected on days 1 and 8 for obtaining baseline information and at weeks 3, 4, 8 and 9. Comprehensive chemistry panels, lipid profile analyses by NMR, measurement of plasma inflammatory marker concentrations, and analyses of cytokine production by activated T lymphocytes and monocytes were performed for each blood draw. Dietary grape powder reduced the plasma concentrations of large LDL-cholesterol and large LDL particles compared with the placebo powder (P< 0·05). The concentrations of interferon-γ, TNF-α, IL-4 and IL-10 were measured in supernatants from peripheral blood mononuclear cells (PBMC) activated with anti-CD3/CD28 antibodies and those of TNF-α, IL-1β, IL-6 and IL-8 were measured in supernatants from PBMC activated with lipopolysaccharide (LPS). No difference in the production of T-cell cytokines was observed between the two intervention groups. The production of IL-1β and IL-6 was increased in supernatants from LPS-activated PBMC in the grape powder group compared with the placebo powder group (P< 0·05). These data suggest that dietary grapes may decrease atherogenic lipid fractions in obese individuals and increase the sensitivity of monocytes in a population at a greater risk of developing infections.

Effect of grape consumption on metabolic parameters in obese adults (831.11)

Consumption of polyphenol‐rich grapes has previously shown cardioprotective effects. This randomized, double‐blind, crossover study aimed to determine the impact of whole grapes on biomarkers of cardiovascular disease risk compared to placebo. We examined plasma lipids, glucose, insulin, and C‐reactive protein in obese adults (mean BMI 39.2 ± 11.7) in good health. Diets included 60 g of whole grape powder (WGP), equivalent to 2 cups whole grapes providing 300 mg total polyphenols, or placebo(C) matched in calories and appearance providing 0 mg polyphenols. Subjects completed two 4‐wk intervention periods, separated by a 2‐wk washout, during which they consumed WGP or C once daily in addition to low polyphenol diets. Fasting blood samples were drawn at beginning and end of each intervention period. Acute postprandial effects at 1, 3, and 5 h were examined following consumption of WGP or C with a standardized high fat, high carbohydrate test meal. Preliminary data reveals subjects receiving WGP had no significant differences in fasting metabolic parameters compared to C, with exception of HDL (p&lt;0.05). Similarly, postprandial AUC for glucose, insulin, and TG did not differ. Further evaluation is needed to determine if grape consumption improves other metabolic biomarkers in the obese population.Grant Funding Source: Supported by CTGC and USDA CRIS CA‐S*‐NTR‐6316‐H

Chondroprotective role of whole grape polyphenols in stimulated SW 1353 cells (830.27)

In aging, increases in oxidative stress and inflammation cause an imbalance in the metabolic activity of chondrocytes leading to onset and progression of osteoarthritis. Resveratrol, a polyphenol rich in grapes has shown to inhibit chondrocyte apoptosis and suppress cyclooxygenase (COX‐2). Our study investigated the effect of whole grape polyphenols on cartilage cell integrity and markers of cartilage health using SW 1353 human chondrosarcoma cells that are compatible to primary chondrocytes. Whole grape polyphenols (WGP) were extracted from grape powder and concentrations were determined using Folin‐Calteau assay. For all experiments, cells treated with WGP were stimulated with the inflammatory compound, tert‐butyl hydroperoxide (tbHP). Cell proliferation significantly (p&lt;.05) increased in a dose dependent manner with WGP at 20ug/ml (147% vs. Control). Cartilage degradation as indicated by glycoprotein‐39 (YKL‐40) levels was significantly lower with the three highest doses of WGP in comparison to control and tbHP stimulated cells. Toluidine blue and Safarin O staining indicated increase presence of type II collagen and proteoglycan in WGP treated cells. Using In‐Cell colorimetric ELISA, we did not observe a significant effect on COX‐2 protein expression with any WGP doses. Elucidation of mechanisms by which WGP protect cartilage cell destruction in presence of an inflammatory agent are warranted.Grant Funding Source: Supported by California Table Grape Commission

Consumption of whole grape powder reduces joint pain and influences serum biomarkers in individuals with self‐reported knee osteoarthritis (1025.10)

Osteoarthritis (OA) is clinically associated with joint pain and stiffness leading to loss of mobility. There is growing interest in use of natural as opposed to invasive therapies in joint pain management. Consumption of grapes, a rich source of polyphenols may reduce inflammation and influence OA outcomes. We have examined the effect of grape consumption on self‐reported pain, joint range‐of‐motion (ROM) and biochemical markers of inflammation (CRP) and cartilage metabolism (IGF‐1, YKL‐40). Using convenience sampling, 72 men and women with knee OA were recruited and assigned to one of two groups. The treatment group (n =28, 21 female) consumed 47 g of freeze‐dried grape powder (FDGP) daily for 4 months. The placebo group (n=28, 21 female) consumed a comparable placebo. For pain related to activity, the FDGP group had a significant decrease from baseline compared to placebo (‐5.3 vs. ‐2.1, p &lt; .05). At midpoint, both groups had a significant reduction in total knee symptoms, evident in the FDGP group only at the end of study. Further, this effect was greater in females. There was no significant change in overall ROM for either group. FDGP intake led to gender specific changes in IGF‐1 compared to placebo group: male (19.9 vs. 2.0 ng/mL, p &lt;.05) and female (3.2 vs. 8.9 ng/mL, p &gt;.05). Whole grape consumption with its bioactive constituents can be a natural alternative to improving symptoms associated with OA.Grant Funding Source: Supported by California Table Grape Commission

Age‐associated effect of freeze‐dried grape powder on inflammatory markers and physical activity in adults with knee osteoarthritis (1025.8)

Osteoarthritis (OA) is the most common joint disease among US adults, leading to pain and disability. Treatment ranges from symptom management to joint replacement, leading many to seek natural dietary approaches. Grapes, rich in anti‐inflammatory polyphenols may aid in management of OA symptoms. The purpose of this study was to assess the effect of grape consumption on physical activity, biochemical markers of inflammation (IL1‐β) and cartilage metabolism (COMP). A total of 72 men and women with knee OA were recruited and randomized. Group 1 (n=28, 21 female) consumed 47 grams of freeze‐dried grape powder (FDGP) daily for four months. Group 2 (n=28, 21 female) consumed 47 grams of a comparable placebo. Self‐reported physical activity and serum specimens were obtained at baseline and at four months. There was a significant decrease in very hard activity in the placebo group. However, a 70 % increase was seen in very hard activity for those &lt;64 yr. in the FDGP group. Participants &gt;65 yr. reported a significant decline in moderate and hard activities (P&lt;.05) in both groups. A statistically significant increase in IL1‐β was observed in both groups, males &gt; females. A greater increase occurred in the placebo group (637.33%) vs. FDGP (194.64%). Levels of IL‐1β and COMP increased more in those &gt;65 yr. Both groups had a statistically significant increase in COMP (154.2% FDGP vs. 172.27% placebo). Longer treatment duration with FDGP may be necessary to see benefits on physical activity levels in this population.Grant Funding Source: Supported by California Table Grape Commission

Metabolic and Inflammatory Signaling are Influenced by Consumption of Polyphenol‐rich Whole‐Fruit Extracts and Purified Phytochemicals in High‐fat Fed Mice (LB419)

A number of reports show that many different phytochemicals favorably influence metabolism and reduce inflammatory markers. Our trial tested the relative potency of purified compounds or whole foods in parallel, using the high‐fat fed C57BL/6J mouse model. The model tested and ranked effects of fruit extracts derived from apple peel, whole sweet cherries and grapes, along with purified compounds including quercetin, resveratrol, and ellagic acid in an attempt to design more‐potent combinations. Polyphenol‐rich fruit extracts and purified compounds were mixed into a high‐fat (60% of total kcal) obesigenic rodent diet and fed to mice along with low‐fat and high‐fat control diets for 10 weeks. Serum circulating factors were measured using a magnetic bead multiplex assay (Milliplex, Millipore Corp.). Mice fed the high‐fat control diet became obese and lost normal glucose control. Serum insulin levels were &gt;1500 pg/mL in the high‐fat controls versus 90% of the high‐fat level (P&lt; 0.01). Quercetin and extracts from grape, cherry, and apple peel also showed improved insulin levels. C‐reactive protein (CRP) concentrations were higher in all high‐fat diet groups except the mice fed a high‐fat diet containing a grape powder product. Our results point to future research in which we plan to compare the relative impact of mixtures of different commonly‐available whole foods on chronic inflammation.Grant Funding Source: Blue Mountain Horticultural Society

Effects of grape powder supplementation on inflammatory and antioxidant markers in hemodialysis patients: a randomized double-blind study.

Polyphenols contained in natural sources such as grapes, have been considered pharmacological agents to combat oxidative stress and inflammation, common features in Chronic Kidney Disease patients. To evaluate the effects of grape powder supplementation on inflammatory and antioxidant biomarkers in hemodialysis (HD) patients. The double-blind placebo-controlled randomized clinical trial evaluated non-diabetic HD patients that received grape powder (500 mg of polyphenols/day) (n = 16, 9 men, 53.0 ± 9.8 years of age, 111.6 ± 58.2 HD months) or placebo (n = 16, 9 men, 52.7 ± 13.7 years of age, 110.4 ± 93.1 HD months) for five weeks. The glutathione peroxidase (GSH-Px) activity and C-reactive protein (CRP) levels were evaluated by ELISA method. After the intervention period, the patients receiving grape powder showed an increase in the GSH-Px activity (16.5 (41.0) to 42.0 (43.3) nmol/min/ml) (p < 0.05) and they did not have the CRP levels increased as seen in placebo group (2.6 (0.28) to 2.8 (0.23 mg/L) (p < 0.05). The use of grape powder as phenolic source could play an important role as an antioxidant and anti-inflammatory agent in non-diabetic HD patients.

Grape Powder Intake Prevents Ovariectomy-Induced Anxiety-Like Behavior, Memory Impairment and High Blood Pressure in Female Wistar Rats

Diminished estrogen influence at menopause is reported to be associated with cognitive decline, heightened anxiety and hypertension. While estrogen therapy is often prescribed to overcome these behavioral and physiological deficits, antioxidants which have been shown beneficial are gaining nutritional intervention and popularity. Therefore, in the present study, utilizing the antioxidant properties of grapes, we have examined effect of 3 weeks of grape powder (GP; 15 g/L dissolved in tap water) treatment on anxiety-like behavior, learning-memory impairment and high blood pressure in ovariectomized (OVX) rats. Four groups of female Wistar rats were used; sham control, sham-GP treated, OVX and OVX+GP treated. We observed a significant increase in systolic and diastolic blood pressure in OVX rats as compared to sham-controls. Furthermore, ovariectomy increased anxiety-like behavior and caused learning and memory impairment in rats as compared to sham-controls. Interestingly, providing grape powder treated water to OVX rats restored both systolic and diastolic blood pressure, decreased anxiety-like behavior and improved memory function. Moreover, OVX rats exhibited an impaired long term potentiation which was restored with grape powder treatment. Furthermore, ovariectomy increased oxidative stress in the brain, serum and urine, selectively decreasing antioxidant enzyme, glyoxalase-1 protein expression in the hippocampus but not in the cortex and amygdala of OVX rats, while grape powder treatment reversed these effects. Other antioxidant enzyme levels, including manganese superoxide dismutase (SOD) and Cu/Zn SOD remained unchanged. We suggest that grape powder by regulating oxidative stress mechanisms exerts its protective effect on blood pressure, learning-memory and anxiety-like behavior. Our study is the first to examine behavioral, biochemical, physiological and electrophysiological outcome of estrogen depletion in rats and to test protective role of grape powder, all in the same study.

Grape Powder Supplementation Prevents Oxidative Stress–Induced Anxiety-Like Behavior, Memory Impairment, and High Blood Pressure in Rats

We examined whether or not grape powder treatment ameliorates oxidative stress–induced anxiety-like behavior, memory impairment, and hypertension in rats. Oxidative stress in Sprague-Dawley rats was produced by using L-buthionine-(S,R)-sulfoximine (BSO). Four groups of rats were used: 1) control (C; injected with vehicle and provided with tap water), 2) grape powder–treated (GP; injected with vehicle and provided for 3 wk with 15 g/L grape powder dissolved in tap water), 3) BSO-treated [injected with BSO (300 mg/kg body weight), i.p. for 7 d and provided with tap water], and 4) BSO plus grape powder–treated (GP+BSO; injected with BSO and provided with grape powder–treated tap water). Anxiety-like behavior was significantly greater in BSO rats compared with C or GP rats (P < 0.05). Grape powder attenuated BSO-induced anxiety-like behavior in GP+BSO rats. BSO rats made significantly more errors in both short- and long-term memory tests compared with C or GP rats (P < 0.05), which was prevented in GP+BSO rats. Systolic and diastolic blood pressure was significantly greater in BSO rats compared with C or GP rats (P < 0.05), whereas grape powder prevented high blood pressure in GP+BSO rats. Furthermore, brain extracellular signal-regulated kinase-1/2 (ERK-1/2) was activated (P < 0.05), whereas levels of glyoxalase-1 (GLO-1), glutathione reductase-1 (GSR-1), calcium/calmodulin-dependent protein kinase type IV (CAMK-IV), cAMP response element–binding protein (CREB), and brain-derived neurotrophic factor (BDNF) were significantly less (P < 0.05) in BSO but not in GP+BSO rats compared with C or GP rats. We suggest that by regulating brain ERK-1/2, GLO-1, GSR-1, CAMK-IV, CREB, and BDNF levels, grape powder prevents oxidative stress–induced anxiety, memory impairment, and hypertension in rats.