Safety evaluation of proanthocyanidin-rich extract from grape seeds

Monocytic differentiation of K562 cells induced by proanthocyanidins from grape seeds

Grape seeds procyanidins can inhibit the proliferation of some cancer cell lines and have strong antioxidant activity. The purpose of this study was to investigate whether grape seeds procyanidins affect the proliferation and redifferentiation in K562 cells. The sulforhodamine B colorimetric assay and trypan blue staining were used to measure cell proliferation and survival. Morphological changes, NBT reductive activity, and surface antigens were used to detect redifferentiation of K562 cells. Intracellular reactive oxygen species (iROS) were detected by a fluorescent probe. Grape seeds procyanidins inhibited cell proliferation but the treatment did not appreciably increase lethality. After treatment with grape seeds procyanidins, a typical differentiated morphology was observed. The positive rate of CD11b and CD14 cells and NBT reductive activities increased significantly. As antioxidants, grape seeds procyanidins can induce arrest in the phase G1 and decrease iROS formation. All results indicate that the antioxidant grape seeds procyanidins are likely to induce monocytic differentiation in leukemia cells, mostly through decreasing iROS formation and inducing phase G1 arrest.

Generation of reactive oxygen species by grape seed extract causes irreparable DNA damage leading to G2/M arrest and apoptosis selectively in head and neck squamous cell carcinoma cells

Head and neck squamous cell carcinoma (HNSCC) accounts for 6% of all malignancies in USA and unfortunately the recurrence of secondary primary tumors and resistance against conventional treatments decrease the overall 5 year survival rate in HNSCC patients. Thus, additional approaches are needed to control HNSCC. Here, for the first time, employing human HNSCC Detroit 562 and FaDu cells as well as normal human epidermal keratinocytes, we investigate grape seed extract (GSE) efficacy and associated mechanism in both cell culture and nude mice xenografts. GSE selectively inhibited the growth and caused cell cycle arrest and apoptotic death in both Detroit 562 and FaDu cells by activating DNA damage checkpoint cascade, including ataxia telangiectasia mutated/ataxia telangiectasia-Rad3-related-checkpoint kinase 1/2-cell division cycle 25C as well as caspases 8, 9 and 3. Consistent with these results, GSE treatment resulted in a strong DNA damage and a decrease in the levels of DNA repair molecules breast cancer gene 1 and Rad51 and DNA repair foci. GSE-caused accumulation of intracellular reactive oxygen species was identified as a major mechanism of its effect for growth inhibition, DNA damage and apoptosis, which was remarkably reversed by antioxidant N-acetylcysteine. GSE feeding to nude mice decreased Detroit 562 and FaDu xenograft tumor growth by 67 and 65% (P < 0.001), respectively. In immunohistochemical analysis, xenografts from GSE-fed groups showed decreased proliferation but increased DNA damage and apoptosis. Together, these findings show that GSE targets both DNA damage and repair and provide mechanistic insights for its efficacy selectively against HNSCC both in cell culture and mouse xenograft, supporting its translational potential against HNSCC.

Oral toxicological studies of black soybean (Glycine max) hull extract: acute studies in rats and mice, and chronic studies in mice

Black soybean (Glycine max) has been used for traditional medicine and food in Asian countries, but safety of its hull has not been studied. We conducted acute and chronic oral toxicity studies. For the acute study, an extract of black soybean hull (BE; 2.5 g/kg body weight) was administered singly by intragastric intubation to Sprague-Dawley rats and C57BL/6 mice. There was no death or significant decrease in body weight in rats and mice, and the oral LD(50) of BE was >2.5 g/kg body weight. In the chronic study, BE was administered at dietary levels of 0% (control), 2.0%, and 5.0% to male and female C57BL/6 mice for 26 weeks. No mortality or toxicologically significant clinical changes were observed through the experimental period. Although body weights, as well as abdominal fat, blood levels of triglyceride and total cholesterol in 5.0% males were significantly lower than that in control and 2.0% groups, these changes were considered not to be adverse. Hematology and histopathological observation revealed no toxicologically significant changes. The no-observed adverse-effect-level of BE was estimated to be 5.0% in the diet (5074.1 mg/kg body weight/day for males and 7617.9 mg/kg body weight/day for females).

The chemoadjuvant potential of grape seed procyanidins on p53-related cell death in oral cancer cells

BACKGROUND

To clarify the efficacy of grape seed procyanidin (GSP) on antiproliferative effects related to p53 functional status of oral squamous cell carcinoma (OSCC) for its chemoadjuvant potential.

METHODS

We used GSP to investigate SCC-25 cells with wild-type p53 gene and OEC-M1 cells with mutant p53 gene for the assessment of antiproliferative effects including cell viability, cell cycle, apoptosis, migration and invasion potential, and alterations of associated oncoproteins involved in cellular and molecular events.

RESULTS

The findings suggest that GSP on OEC-M1 cells leads to cell cycle arrest by increasing the expression of p21(Cip1) /p27(Kip1) protein without functioning mitochondria-mediated apoptosis, whereas GSP on SCC-25 cells inhibits cell proliferation via both G1-phase arrest and mitochondria-mediated apoptosis in a dose-dependent manner as a result of alterations of Bcl-2. GSP also inhibits the migration and invasion of both cells, which are associated with the suppression of matrix metalloproteinases (MMPs), MMP-2 and MMP-9.

CONCLUSION

Antiproliferative effectiveness of GSP is closely associated with the p53 status of OSCC cells. GSP displays chemoadjuvant potential via cell cycle blockage and apoptotic induction. Our findings clearly suggest that GSP may play a role as a novel chemopreventive or therapeutic agent for OSCC.

Epigenetic alterations in ultraviolet radiation-induced skin carcinogenesis: interaction of bioactive dietary components on epigenetic targets

The importance of epigenetic alterations in the development of various diseases including the cancers has been realized. As epigenetic changes are reversible heritable changes, these can be utilized as an effective strategy for the prevention of cancers. DNA methylation is the most characterized epigenetic mechanism that can be inherited without changing the DNA sequence. Although limited available data suggest that silencing of tumor suppressor genes in ultraviolet (UV) radiation-exposed epidermis leads to photocarcinogenesis and is associated with a network of epigenetic modifications including alterations in DNA methylation, DNA methyltransferases and histone acetylations. Various bioactive dietary components have been shown to protect skin from UV radiation-induced skin tumors in animal models. The role of bioactive dietary components, such as, (-)-epicatechins from green tea and proanthocyanidins from grape seeds has been assessed in chemoprevention of UV-induced skin carcinogenesis and underlying epigenetic mechanism in vitro and in vivo animal models. These bioactive components have the ability to block UV-induced DNA hypermethylation and histone modifications in the skin required for the silencing of tumor suppressor genes (e.g. Cip1/p21, p16(INK4a) ). This information is of importance for understanding the role of epigenetic modulation in UV-induced skin tumor and the chemopreventive mechanism of bioactive dietary components.

The effect of transient proanthocyanidins preconditioning on the cross-linking and mechanical properties of demineralized dentin

Proanthocyanidin-based preconditioners were prepared by adding powdered proanthocyanidins-rich grape seed extract to various solvents at different concentrations. Demineralized dentin specimens were preconditioned for 20, 30, 60 or 120 s, followed by the evaluation of their cross-linking degree, mechanical properties and micromorphology. The cross-linking degree of the demineralized dentin collagen exhibited concentration- and time- dependent increase after preconditioning treatment, irrespective of the preconditioner and the solvent. When treated for the same exposure time, specimens after 15% proanthocyanidins preconditioning resulted in the highest mean ultimate tensile strength compared with all the other groups tested. Five percent glutaraldehyde control group produced the highest cross-linking degree, but the ultimate tensile strength was lower than that of 15% proanthocyanidins group. The field emission scanning electron microscopy confirmed that the demineralized dentin collagen was in a homogeneous and regular arrangement after preconditioning and maintained expanding, regardless of the surface moisture conditions.

Improvement of mitochondrial function in muscle of genetically obese rats after chronic supplementation with proanthocyanidins

The aim of this study was to determine the effect of chronic dietary supplementation of a grape seed proanthocyanidin extract (GSPE) at a dose of 35 mg/kg body weight on energy metabolism and mitochondrial function in the skeletal muscle of Zucker obese rats. Three groups of 10 animals each were used: lean Fa/fa lean group (LG) rats, a control fa/fa obese group (OG) of rats, and an obese supplemented fa/fa proanthocyanidins obese group (POG) of rats, which were supplemented with a dose of 35 mg GSPE/kg of body weight/day during the 68 days of experimentation. Skeletal muscle energy metabolism was evaluated by determining enzyme activities, key metabolic gene expression, and immunoblotting of oxidative phosphorylation complexes. Mitochondrial function was analyzed by high-resolution respirometry using both a glycosidic and a lipid substrate. In muscle, chronic GSPE administration decreased citrate synthase activity, the amount of oxidative phosphorylation complexes I and II, and Nrf1 gene expression, without any effects on the mitochondrial oxidative capacity. This situation was associated with lower reactive oxygen species (ROS) generation. Additionally, GSPE administration enhanced the ability to oxidize pyruvate, and it also increased the activity of enzymes involved in oxidative phosphorylation including cytochrome c oxidase. There is strong evidence to suggest that GSPE administration stimulates mitochondrial function in skeletal muscle specifically by increasing the capacity to oxidize pyruvate and contributes to reduced muscle ROS generation in obese Zucker rats.

Lack of toxicological effect through mutagenicity test of polyphenol extracts from peanut shells

The toxicological effect of polyphenols extracted from peanut shells was investigated in animal models. The safety data were needed to proceed with further clinical trials. The oral LD50 of peanut shells polyphenols was determined to be higher than 15,000mg/kg body weight. We also carried out a sperm abnormality test, a chromosomal aberration test and a micronucleus test in rats. The peanut shell polyphenols did not cause any abnormalities in the system. Furthermore, the administration of peanut shell polyphenols did not significantly alter changes in body weight or clinical signs. These results strongly indicated that peanut shell polyphenols did not induce mutagenicity. The results of this study suggested a lack of toxicological effect and supported the further use of polyphenol-rich extracts from peanut shells as a potential natural antioxidant.

Grape seed extract for control of human enteric viruses

Grape seed extract (GSE) is reported to have many pharmacological benefits, including antioxidant, anti-inflammatory, anticarcinogenic, and antimicrobial properties. However, the effect of this inexpensive rich source of natural phenolic compounds on human enteric viruses has not been well documented. In the present study, the effect of commercial GSE, Gravinol-S, on the infectivity of human enteric virus surrogates (feline calicivirus, FCV-F9; murine norovirus, MNV-1; and bacteriophage MS2) and hepatitis A virus (HAV; strain HM175) was evaluated. GSE at concentrations of 0.5, 1, and 2 mg/ml was individually mixed with equal volumes of each virus at titers of ∼7 log(10) PFU/ml or ∼5 log(10) PFU/ml and incubated for 2 h at room temperature or 37°C. The infectivity of the recovered viruses after triplicate treatments was evaluated by standardized plaque assays. At high titers (∼7 log(10) PFU/ml), FCV-F9 was significantly reduced by 3.64, 4.10, and 4.61 log(10) PFU/ml; MNV-1 by 0.82, 1.35, and 1.73 log(10) PFU/ml; MS2 by 1.13, 1.43, and 1.60 log(10) PFU/ml; and HAV by 1.81, 2.66, and 3.20 log(10) PFU/ml after treatment at 37°C with 0.25, 0.50, and 1 mg/ml GSE, respectively (P < 0.05) in a dose-dependent manner. GSE treatment of low titers (∼5 log(10) PFU/ml) at 37°C also showed viral reductions. Room-temperature treatments with GSE caused significant reduction of the four viruses, with higher reduction for low-titer FCV-F9, MNV-1, and HAV compared to high titers. Our results indicate that GSE shows promise for application in the food industry as an inexpensive novel natural alternative to reduce viral contamination and enhance food safety.

Cranberry and Grape Juices Affect Tight Junction Function and Structural Integrity of Rotavirus-Infected Monkey Kidney Epithelial Cell Monolayers

Cranberry juice (CJ) and grape juice (GJ) from Vaccinium macrocarpon and Vitis labrusca, respectively, and purified proanthocyanidins (PACs) from these species are recognized to possess antiviral activity. The effects of CJ and GJ on tight junction (TJ) structure and function among rotavirus-infected monkey kidney epithelial cells (MA-104) in monolayer cultures were evaluated. Antiviral activity by cranberry PACs of rotavirus in cell-free suspension was investigated by a rotavirus antigen [i.e., viral capsid protein 6 (VP6)] capture enzyme-linked immunosorbent assay (ELISA) and by transmission electron microscopy (TEM). MA-104 monolayers were treated with CJ, GJ, or cranberry juice cocktail (CJC) drink before inoculation with rotavirus. TJ function and structural integrity were measured by changes in transepithelial electrical resistance (TEER) and by reduction of signal intensity of the TJ α-claudin 1 by immunofluorescence. The inhibitory activity of CJ and GJ on viral RNA synthesis, as a function of viral concentration, was determined by reverse transcription polymerase chain reaction (rtPCR). After 4 days, virus-infected monolayers pretreated with GJ (Concord and Niagara GJs) had TEER readings similar to uninfected controls. CJ and CJC also had a significant protective effect (P < 0.05) on TJ function, but to a lesser extent than GJ. Disorganization of TJ integrity commenced at 24- to 36-h post-viral inoculation, but this effect was reduced by pretreatment with CJ or GP of monolayer cultures. TEM showed aggregation of rotavirus by cranberry PACs. The destruction of rotavirus capsid proteins VP6, in cell-free suspension was inversely related to the concentration of cranberry PACs (C-PAC). Loss of rotavirus RNA by CJ or GJ was inversely related to viral infectivity titers. CJ, GJ, or PAC-associated antiviral activity has been linked to modifications in cellular physiologic events and to physical factors (e.g., PAC-mediated viral aggregation) that probably compromise viral infectivity. Multiple cell physiological and physical events must be considered when determining the mechanisms associated with the antiviral (i.e., rotavirus) activity of CJ, GJ, and PACs.

Grape seed extract upregulates p21 (Cip1) through redox-mediated activation of ERK1/2 and posttranscriptional regulation leading to cell cycle arrest in colon carcinoma HT29 cells

Abnormalities in cell cycle progression provide unlimited replicative potential to cancer cells, and therefore targeting of key cell cycle regulators could be a sound cancer chemopreventive strategy. Earlier, we found that grape seed extract (GSE) increases Cip/p21 protein level and inhibits growth and induces apoptosis in human colon carcinoma HT29 cells both in vitro and in vivo. However, the mechanism of GSE-induced p21 upregulation and its role in biological efficacy of GSE are not known, which were investigated here. GSE treatment of HT29 cells resulted in a strong dose- and time-dependent phosphorylation of extracellular signal regulated kinase 1/2 (ERK1/2), consistent with p21 induction. The inhibition of sustained ERK1/2 activation by GSE using pharmacological inhibitors abrogated GSE-induced p21 upregulation. Furthermore, pretreatment of cells with N-acetylcysteine inhibited GSE-induced ERK1/2 phosphorylation as well as p21 upregulation, suggesting the involvement of GSE-induced oxidative stress as an upstream event. Consistent with this, GSE also decreased intracellular level of reduced glutathione. Next, we determined whether GSE-induced signaling regulates p21 expression at transcriptional and/or translational levels. GSE was found to increase the stability of p21 message with resultant increase in p21 protein level, but it did not alter the protein stability to a great extent. Importantly, knock-down of p21 abrogated GSE-induced G(1) arrest suggesting that p21 induction by GSE is essential for its G(1) arrest effect. Together, our results for the first time identify a central role of p21 induction and associated mechanism in GSE-induced cell cycle arrest in HT29 cells.

Targets of Red Grapes: Oxidative Damage of DNA and Leukaemia Cells

Vitis vinifera is a widespread crop all over the world. The biophenols present in grapes have a remarkable influence on wine quality and also confer potential health-protecting properties to this fruit. The aim of the present work was to assess the beneficial properties of skin, seeds and pulp of red table grapes (RTG) ( Vitis vinifera, Palieri Cadiz variety). Two potential beneficial activities of red table grapes (RTG) were analyzed: (i) The maintenance of genomic stability studying their genotoxic/antigenotoxic effects, and (ii) the in vitro cytotoxic effect against tumor cells of RTG components.

The genotoxic and/or antigenotoxic effect was measured applying the somatic mutation and recombination test on wing imaginal discs of Drosophila melanogaster. The cytotoxic effect was monitored using the HL60 human leukemia model to evaluate the antiproliferative potential of the different parts of RTG. The three major parts (skin, seeds and pulp) are not genotoxic. When antigenotoxicity assays were performed using hydrogen peroxide as the oxidative genotoxin, skin, seed and pulp exerted a desmutagenic effect, with seeds and skin showing the most potent effect. The cytotoxicity tests using HL60 cells indicated that only skin and pulp fractions are able to inhibit the tumor growth, with skin having the lowest IC50 (1.8 mg/mL versus 8 mg/mL of pulp). These results suggest that RTG are potent anti-mutagens that protect DNA from oxidative damage as well as being cytotoxic toward the HL60 tumor cell line.

Nanomechanical properties of biochemically modified dentin bonded interfaces

The effect of biomodification of dentin matrices using collagen cross-linkers, glutaraldehyde (GD) and grape seed extract (GSE), on the reduced modulus of elasticity (Er) and nanohardness (H) of the hybrid layer and underlying dentin was investigated at the dentin-resin bonded interface. The coronal dentin of nine molars were exposed and divided into groups: 5% GD, 6·5% GSE and control. Control samples were etched, bonded with Adper Single Bond Plus and Premise composite. GD and GSE were applied for 1 h prior to bonding procedures. After 24 h, samples were sectioned, and resin-dentin beams were either kept in distilled water or exposed to collagenase treatment for 24 h. Nano-indentations were performed at the hybrid layer and underlying dentin. GD and GSE treatment increased the Er and H of resin-dentin interface structures when compared to the control group (P<0·05), particularly the hybrid layer, and may be a promising novel approach to strengthen the dentin-resin bonded interface structures when using these adhesive system and resin-based composite.

Proanthocyanidins produce significant attenuation of doxorubicin-induced mutagenicity via suppression of oxidative stress

This study has been initiated to determine whether proanthocyanidins can protect against doxorubicin-induced mutagenicity in mice and to elucidate the potential mechanism of this protection. Pretreatment of mice with proanthocyanidins (100 mg/kg/day, orally) for 7 days and simultaneously with doxorubicin (12 mg/kg, i.p.) for another day, significantly reduced the frequency of bone marrow DNA strand breaks and micronucleated polychromatic erythrocytes compared to doxorubicin-treated mice alone. Furthermore, proanthocyanidins caused a reduction in bone marrow suppression induced by doxorubicin treatment. In male germline, orally administration of proanthocyanidins (100 mg/kg/day, orally) for 7 consecutive days before and 7 consecutive days after treatment with doxorubicin (12 mg/kg, i.p.), significantly elevated the levels of sperm count and motility reduced by doxorubicin treatment. Furthermore, proanthocyanidins significantly decreased the elevated levels of spermatogonial and spermatocyte chromosomal aberrations and sperm head abnormality induced by doxorubicin. Prior administration of proanthocyanidins ahead of doxorubicin reduced the doxorubicin induced testicular lipid peroxidation and prevented the reduction in testicular non-protein sulfhydryl significantly. Conclusively, this study provides for the first time that proanthocyanidins have a protective role in the abatement of doxorubicin-induced mutagenesis and cell proliferation changes in germinal cells of mice that reside, at least in part, in their radical scavenger activity. Therefore, proanthocyanidins can be a promising chemopreventive agent to avert secondary malignancy and abnormal reproductive outcomes risks in cancer patients receiving doxorubicin-involved treatment.

Mutagenicity and safety evaluation of ethanolic extract of Prunus mume

The ethanolic extract of Prunus mume (EPM) is a novel polyphenol preparation derived from branches (with leaves) of Prunus mume, which could be used as a functional ingredient for antioxidant and antiobesity therapy. The purpose of this study was to evaluate the safety of EPM. An EPM was prepared and evaluated for oral acute and subacute toxicity in Sprague-Dawley rats, while its mutagenic potential was assessed by a reverse mutation test using Salmonella typhimurium, by a bone marrow cell micronucleus test using ICR mice, and by a sperm abnormality test using ICR mice. The results showed no acute lethal effects at the maximal tested EPM dose of 20 g/kg bw in either rats or mice, suggesting that EPM can be regarded as virtually nontoxic. Administration at levels of 0.84, 1.67, and 3.33 g/kg bw to rats for 30 d did not induce any significant hematological, clinical, chemical, or histopathological changes. No mutagenicity evidence was detected in any of the 3 mutagenic tests. The level of "no observed adverse effect" (NOAEL) for EPM was above 3.33 g/kg bw for the subacute toxicity study.

Protective effects of grape seed proanthocyanidin extracts on cerebral cortex of streptozotocin-induced diabetic rats through modulating AGEs/RAGE/NF-kappaB pathway

Diabetic encephalopathy is a severe complication in patients with long-term hyperglycemia. Oxidative stress is thought to be closely implicated in this disorder, so in this study, we examined whether grape seed proanthocyanidin extract (GSPE), a naturally occurring antioxidant derived from grape seeds, could reduce the injuries in the cerebral cortex of diabetic rats by modulating advanced glycation end products (AGEs)/the receptor for AGEs (RAGE)/nuclear factor-kappa B p65 (NF-kappaB p65) pathway, which is crucial in oxidative stress. Body weight and serum AGEs were tested; cerebral cortexes were isolated for morphological observations and the pyramidal cell layers were immunohistochemically stained for the detection of RAGE, NF-kappaB p65, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) as well. For RAGE and NF-kappaB p65, quantitative reverse transcriptase coupled to polymerase chain reaction (RT-PCR) was employed for determination of mRNA levels, and western blot was used to detect protein expression. Our results showed that long term hyperglycemia in diabetic rats caused the degeneration of neurons and the up-regulation of serum AGEs, and also the up-regulation of RAGE, NF-kappaB p65, VCAM-1 and ICAM-1 in the brain. We found that GSPE treatment improved the pathological changes of diabetic rats by modulating the AGEs/RAGE/NF-kappaB p65 pathway. This study enables us to further understand the key role that the AGEs/RAGE/NF-kappaB pathway plays in the pathogenesis of diabetic encephalopathy, and confirms that GSPE might be a therapeutical means to the prevention and treatment of this disorder.

Should Red Wine Be Considered a Functional Food?

  Functional foods may be regarded as foods that have nutritional value, but in particular, they also have beneficial effects on one or more body functions. Thus, functional foods may improve health and/or reduce the risk of developing certain diseases when taken in amounts that can be consumed in a normal diet. Based on nearly 2 decades of research since the term "French paradox" was first coined in 1992, wine would appear to fit this definition. Yet there seems to be reluctance to consider wine as a functional food. In this review, we present an overview of the accumulated evidence for the health benefits of wine-and its key phenolic components such as resveratrol, quercetin, catechin-and show that these alone are not enough to firmly establish wine as a functional food. What is required is to create clearly defined products based on wine that are targeted to consumers' needs and expectations when it comes to purchasing functional foods. Moreover, the crucial question of alcohol and health also needs to be addressed by the functional food industry. Suggestions are presented for working through this issue, but in many regards, wine is like any other food-it should be consumed sensibly and in amounts that are beneficial to health. Overindulgence of any kind does not promote good health.

Dietary-feeding of grape seed extract prevents azoxymethane-induced colonic aberrant crypt foci formation in fischer 344 rats

Chemoprevention by dietary agents/supplements has emerged as a novel approach to control various malignancies, including colorectal cancer (CRC). This study assessed dietary grape seed extract (GSE) effectiveness in preventing azoxymethane (AOM)-induced aberrant crypt foci (ACF) formation and associated mechanisms in Fischer 344 rats. Six-week-old rats were injected with AOM, and fed control diet or the one supplemented with 0.25% or 0.5% (w/w) GSE in pre- and post-AOM or only post-AOM experimental protocols. At 16 wk of age, rats were sacrificed and colons were evaluated for ACF formation followed by cell proliferation, apoptosis, and molecular analyses by immunohistochemistry. GSE-feeding caused strong chemopreventive efficacy against AOM-induced ACF formation in terms of up to 60% (P < 0.001) reduction in number of ACF and 66% (P < 0.001) reduction in crypt multiplicity. Mechanistic studies showed that GSE-feeding inhibited AOM-induced cell proliferation but enhanced apoptosis in colon including ACF, together with a strong decrease in cyclin D1, COX-2, iNOS, and survivin levels. Additional studies showed that GSE-feeding also decreased AOM-caused increase in beta-catenin and NF-kappaB levels in colon tissues. Compared to control animals, GSE alone treatment did not show any considerable change in these biological and molecular events in colon, and was nontoxic. Together, these findings show the chemopreventive efficacy of GSE against the early steps of colon carcinogenesis in rats via likely targeting of beta-catenin and NF-kappaB signaling, and suggest its potential usefulness for the prevention of human CRC.

The role of lipid and carbohydrate digestive enzyme inhibitors in the management of obesity: a review of current and emerging therapeutic agents

Obesity is a global epidemic associated with significant morbidity and mortality in adults and ill health in children. A proven successful approach in weight management has been the disruption of nutrient digestion, with orlistat having been used to treat obesity for the last 10 years. Although orlistat-induced weight loss remains modest, it produces meaningful reductions in risk factors for obesity-related conditions such as diabetes and cardiovascular disease. Moreover, this lipase inhibitor is free of the serious side effects that have dogged appetite-suppressing drugs. This success had driven investigation into new generation nutraceuticals, supplements and pharmaceutical agents that inhibit the breakdown of complex carbohydrates and fats within the gut. This review focuses on agents purported to inhibit intestinal enzymes responsible for macronutrient digestion. Except for some synthetic products, the majority of agents reviewed are either botanical extracts or bacterial products. Currently, carbohydrate digestion inhibitors are under development to improve glycemic control and these may also induce some weight loss. However, colonic fermentation induced side effects, such as excess gas production, remain an issue for these compounds. The α-glucosidase inhibitor acarbose, and the α-amylase inhibitor phaseolamine, have been used in humans with some promising results relating to weight loss. Nonetheless, few of these agents have made it into clinical studies and without any clinical proof of concept or proven efficacy it is unlikely any will enter the market soon.

Apple proanthocyanidins do not reduce the induction of preneoplastic lesions in the colon of rats associated with human microbiota

Since the gut microbiota metabolizes various dietary constituents unabsorbed by the small intestine and modulates colon function, it plays an essential role in colon carcinogenesis. First, we have developed a model of human microbiota-associated rats (HMA), fed a human-type diet and injected with 1-2,dimethylhydrazine (DMH). We observed that the number and size of DMH-induced aberrant crypt foci (ACF) were significantly higher in HMA rats than in germ-free or conventional rats. Second, we used this model to assess the protective effect of an apple proanthocyanidin-rich extract (APE) on colon carcinogenesis. In this model, ACF number and multiplicity were not reduced by APE at 0.001% and 0.01% in drinking water. They were higher with APE 0.1% than with APE 0.01%. Therefore, the cross-talk between human microbiota and the colon epithelium should be taken into account in carcinogenesis models. Moreover, attention should be paid prior to using proanthocyanidin extracts as dietary supplements for humans.

Procyanidins extracted from the lotus seedpod ameliorate scopolamine-induced memory impairment in mice

The major purpose of this study was to determine the effect of procyanidins extracted from the lotus seedpod (LSPC) on the learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) in mice. The capacities of memory and learning were evaluated by the Morris water maze and the step-down avoidance test. LSPC (50, 100, 150 mg/kg BW, p.o.) significantly reversed scopolamine-induced learning and memory impairments in the Morris water maze test, as evaluated by shortened escape latency and swimming distance. In the step-down avoidance test, LSPC (50, 100, 150 mg/kg BW, p.o.) treatment significantly reduced the number of errors and shortened latency compared with that of scopolamine. In addition, LSPC was also found to inhibit acetyl cholinesterase (AChE) activity. These results of this study suggest that LSPC may play a useful role in the treatment of cognitive impairment caused by AD and aging.

The mixture of procyanidins extracted from the lotus seed pod and bilobalide ameliorates scopolamine-induced memory impairment in mice

OBJECTIVE

To study the co-effect of procyanidins extracted from the lotus seed pod (LSPC) and bilobalide (BIL) on ameliorating scopolamine-induced learning and memory impairment in young mice.

METHODS

Fifty male Kunming mice with similar learning and memory capabilities were selected by Morris water maze test and were randomized into 5 groups (n=10 in each group): control group, scopolamine group, L-(LSPC+BIL) group (50 mg/kg LSPC+10 mg/kg BIL), M-(LSPC+BIL) group (100 mg/kg LSPC+20 mg/kg BIL), H-(LSPC+BIL) group (150 mg/kg LSPC+30 mg/kg BIL). Scopolamine model with impaired learning and memory was established by scopolamine treatment (1 mg/kg), and after 10 min mice were tested. In L-, M-, and H-(LSPC+BIL) groups, mice were treated with LSPC and BIL ig. for 30 days, while mice in the other 2 groups were treated with normal saline ig. instead. After the 30-day's treatment, the co-effect of LSPC and BIL on learning and memory was tested by Morris water maze and the step-down avoidance tests.

RESULTS

The memory impairment caused by scopolamine in young mice could be ameliorated by co-treatment of LSPC and BIL, as indicated by significantly shorter escape latency and swimming distance in the Morris water maze test, when compared with those in the scopolamine group. In the step-down avoidance test, mice in all the 3 dose groups showed significantly smaller number of errors and longer latency than mice in the scopolamine group did.

CONCLUSION

Co-treatment of LSPE and BIL can ameliorate scopolamine-induced learning and memory impairment in young mice.

Grape products and oral health

Oral diseases, including dental caries, periodontal disease, and tooth loss, affect the majority of the population and can affect a person's overall health. Raisins contain polyphenols, flavonoids, and high levels of iron that may benefit human health. However, their oral health benefits are less well understood. We hypothesized that raisins contain antimicrobial phytochemicals capable of suppressing oral pathogens associated with caries or periodontal diseases and thus benefit oral health. Through antimicrobial assay-guided fractionation and purification, compounds identified with growth inhibition against oral pathogens were oleanolic acid, oleanolic aldehyde, linoleic acid, linolenic acid, betulin, betulinic acid, 5-(hydroxymethyl)-2-furfural, rutin, beta-sitosterol, and beta-sitosterol glucoside. Oleanolic acid suppressed in vitro adherence of cariogenic Streptococcus mutans biofilm. When the effect of raisins and raisin-containing bran cereal on in vivo plaque acidogenicity was examined in 7- to 11-y-old children, it was found that raisins did not reduce the plaque pH decline below pH 6 over the 30-min test period. Compared with commercial bran flakes or raisin bran cereal, a lower plaque pH drop was noted in children who consumed a raisin and bran flake mixture when no sugar was added (P < 0.05). Grape seed extract, high in proanthocyanidins, positively affected the in vitro demineralization and/or remineralization processes of artificial root caries lesions, suggesting its potential as a promising natural agent for noninvasive root caries therapy. Raisins represent a healthy alternative to the commonly consumed sugary snack foods.

In vivo, in vitro, and in silico studies of Cu/Zn-superoxide dismutase regulation by molecules in grape seed procyanidin extract

The potential beneficial effects of flavonoids on human health have aroused considerable interest and were initially attributed to their antioxidant activities. Recent studies have speculated that as well as their antioxidant role, flavonoids can act by modulating cell signaling pathways and/or gene expression. In this respect, we have used streptozotocin-induced diabetic rats as an oxidative stress model to study whether grape seed procyanidin extract (GSPE) regulates copper/zinc-superoxide dismutase (Cu/Zn-SOD), an enzyme that defends against oxidative stress. The results indicate that the expression profile of Cu/Zn-SOD in diabetic rats was similar to the profile in nondiabetic rats. Nevertheless, the administration of GSPE increased Cu/Zn-SOD activity in both diabetic and nondiabetic rats. Therefore, to evaluate whether this increase in activity was dose-dependent, we also studied the effect of GSPE on Cu/Zn-SOD expression by using an in vitro model (Fao cell line hepatocytes). The cells were exposed to GSPE doses between 0 and 150 mg/L for 24 h, and the results showed that enzyme activity was enhanced only with 15 mg/L of GSPE. Therefore, we decided to explore whether this increase in Cu/Zn-SOD activity was due to direct interaction between some of the molecules in GSPE and the enzyme (in vitro experiments) and, if so, to analyze how this interaction occurs (in silico experiments). The results of these studies showed that direct interaction between some small- or medium-sized GSPE components and the enzyme is responsible for the increase in Cu/Zn-SOD activity.

Induction of apoptosis in human leukemia cells by grape seed extract occurs via activation of c-Jun NH2-terminal kinase

PURPOSE

To characterize the functional role of c-Jun NH(2)-terminal kinase (JNK) and other apoptotic pathways in grape seed extract (GSE)-induced apoptosis in human leukemia cells by using pharmacologic and genetic approaches.

EXPERIMENTAL DESIGN

Jurkat cells were treated with various concentrations of GSE for 12 and 24 h or with 50 microg/mL GSE for various time intervals, after which apoptosis, caspase activation, and cell signaling pathways were evaluated. Parallel studies were done in U937 and HL-60 human leukemia cells.

RESULTS

Exposure of Jurkat cells to GSE resulted in dose- and time-dependent increase in apoptosis and caspase activation, events associated with the pronounced increase in Cip1/p21 protein level. Furthermore, treatment of Jurkat cells with GSE resulted in marked increase in levels of phospho-JNK. Conversely, interruption of the JNK pathway by pharmacologic inhibitor (e.g., SP600125) or genetic (e.g., small interfering RNA) approaches displayed significant protection against GSE-mediated lethality in Jurkat cells.

CONCLUSIONS

The result of the present study showed that GSE induces apoptosis in Jurkat cells through a process that involves sustained JNK activation and Cip1/p21 up-regulation, culminating in caspase activation.

Influence of dietary feeding of low monomer content grape seed extract on vitellogenin production and cholesterol levels in goldfish, Carassius auratus

Grape seed extract (GSE) is a source of naturally occurring compounds known as proanthocyanidins and flavan-3-ols, which are recognized to exert a protective effect on human health, so GSE is widely used mainly as a nutritional supplement. However, polyphenols may have, in some cases, estrogenic effects or may interfere with the endocrine system. For that reason, it was considered of interest to investigate the beneficial or detrimental effects induced by low monomer content grape seed extract (LMC-GSE) in a teleost experimental model, the juvenile goldfish (Carassius auratus); therefore, biomarkers of estrogenic exposure together with cholesterol titers were assessed in both plasma and tissue samples taken from fish fed with different doses of LMC-GSE for 4 weeks. Dietary LMC-GSE (71 or 35 mg/g diet) did not affect vitellogenin (VTG) synthesis; on the contrary, VTG production was exclusively induced in fish fed with an estradiol-17beta (E2)-incorporated diet. In addition, it was found that both plasma E2 levels and hepatic total cholesterol were not affected by LMC-GSE dietary regimens.

The effect of OPC Factor on energy levels in healthy adults ages 45-65: a phase IIb randomized controlled trial

OBJECTIVE

To determine the efficacy of the food supplement OPC Factor to increase energy levels in healthy adults aged 45 to 65.

DESIGN

Randomized, placebo-controlled, triple-blind crossover study.

SUBJECTS

Twenty-five (25) healthy adults recruited from the University of Pennsylvania Health System.

INTERVENTIONS

OPC Factor,trade mark (AlivenLabs, Lebanon, TN) a food supplement that contains oligomeric proanthocyanidins from grape seeds and pine bark along with other nutrient supplements including vitamins and minerals, was in the form of an effervescent powder. The placebo was similar in appearance and taste.

OUTCOME MEASURES

Five outcome measurements were performed: (1) Energy subscale scores of the Activation-Deactivation Adjective Check List (AD ACL); (2) One (1) global question of percent energy change (Global Energy Percent Change); (3) One (1) global question of energy change measured on a Likert scale (Global Energy Scale Change); 4. One (1) global question of percent overall status change (Global Overall Status Percent Change); and (5) One (1) global question of overall status change measured on a Likert scale (Global Overall Status Scale Change).

RESULTS

There were no carryover/period effects in the groups randomized to Placebo/Active Product sequence versus Active Product/Placebo sequence. Examination of the AD ACL Energy subscale scores for the Active Product versus Placebo comparison revealed no significant difference in the intention-to-treat (IT) analysis and the treatment received (TR) analysis. However, Global Energy Percent Change (p = 0.06) and Global Energy Scale Change (p = 0.09) both closely approached conventional levels of statistical significance for the active product in the IT analysis. Global Energy Percent Change (p = 0.05) and Global Energy Scale Change (p = 0.04) reached statistical significance in the TR analysis. A cumulative percent responders analysis graph indicated greater response rates for the active product.

CONCLUSIONS

OPC Factor may increase energy levels in healthy adults aged 45-65 years. A larger study is recommended. Clinical Trials.gov identifier: NCT03318019.

Grape seed extract (Vitis vinifera) partially reverses high fat diet-induced obesity in C57BL/6J mice

The aim of the present study was to assess the anti-obesity effects of grape seed extract (GSE) supplement in C57BL/6J mice. Thirty mice were divided into three groups; normal diet control group (ND), high fat diet control group (HD) and high fat diet plus grape seed extract supplemented group (HD+GSE). Results were as follows: 1. GSE supplement reduced the weight gain in mice fed high fat diets; epididymal and back fat weights were lower compared to non-supplemented HD group. 2. Blood lipid concentrations were lower in the HD+GSE group than in the HD group. Serum HDL-C concentrations were higher in the HD+GSE group compared with the other groups. 3. The concentrations of acid-insoluble acylcarnitines (AIAC) in serum and liver were higher in the HD+GSE group than in the HD group. 4. GSE supplementation increased mRNA levels of lipolytic genes such as carnitine palmitoyltransferase-1 (CPT-1) and decreased mRNA levels of lipogenic genes such as acetyl CoA carboxylase (ACC). These findings suggest that grape seed extract supplements in high fat diet might normalize body weight, epididymal and back fat weights, lipid concentrations, and carnitine levels through controlling lipid metabolism.

Biosynthesis and genetic regulation of proanthocyanidins in plants

Proanthocyanidins (PAs), also known as condensed tannins, are a group of polyphenolic secondary metabolites synthesized in plants as oligomers or polymers of flavan-3-ol units via the flavonoid pathway. Due to their structural complexity and varied composition, only in the recent years has the study on the biosynthesis and regulation of PAs in plants taken off, although some details of the synthetic mechanism remain unclear. This paper aims to summarize the status of research on the structures of PAs in plants, the genes encoding key enzymes of biosynthetic pathway, the transport factors, the transcriptional regulation of PA biosynthesis and the genetic manipulation of PAs. The problems of this field were also discussed, including the nature of the final "enzyme" which catalyzes the polymerization reaction of PAs and the possible mechanism of how the elementary units of flavanols are assembled in vivo.

Grape seed proanthocyanidines and skin cancer prevention: inhibition of oxidative stress and protection of immune system

Overexposure of the skin to UV radiation has a variety of adverse effects on human health, including the development of skin cancers. There is a need to develop nutrition-based efficient chemopreventive strategies. The proanthocyanidins present in grape seeds (Vitis vinifera) have been shown to have some biological effects, including prevention of photocarcinogenesis. The present communication discusses the in vitro and in vivo studies of the possible protective effect of grape seed proanthocyanidins (GSPs) and the molecular mechanism for these effects. In SKH-1 hairless mice, dietary supplementation with GSPs is associated with a decrease of UVB-induced skin tumor development in terms of tumor incidence, tumor multiplicity, and a decrease in the malignant transformation of papillomas to carcinomas. It is suggested that the chemopreventive effects of dietary GSPs are mediated through the attenuation of UV-induced: (i) oxidative stress; (ii) activation of mitogen-activated protein kinases and nuclear factor-kappa B (NF-kappaB) signaling pathways; and (iii) immunosuppression through alterations in immunoregulatory cytokines. Collectively, these studies indicate protective potential of GSPs against experimental photocarcinogenesis in SKH-1 hairless mice, and the possible mechanisms of action of GSPs, and suggest that dietary GSPs could be useful in the attenuation of the adverse UV-induced health effects in human skin.

In vitro remineralization effects of grape seed extract on artificial root caries

Grape seed extract (GSE) contains proanthocyanidins (PA), which has been reported to strengthen collagen-based tissues by increasing collagen cross-links. We used an in vitro pH-cycling model to evaluate the effect of GSE on the remineralization of artificial root caries. Sound human teeth fragments obtained from the cervical portion of the root were stored in a demineralization solution for 96 h at 37 degrees C to induce artificial root caries lesions. The fragments were then divided into three treatment groups including: 6.5% GSE, 1,000 ppm fluoride (NaF), and a control (no treatment). The demineralized samples were pH-cycled through treatment solutions, acidic buffer and neutral buffer for 8 days at 6 cycles per day. The samples were subsequently evaluated using a microhardness tester, polarized light microscopy (PLM) and confocal laser scanning microscopy (CLSM). Data were analyzed using ANOVA and Fisher's tests (p<0.05). GSE and fluoride significantly increased the microhardness of the lesions (p<0.05) when compared to a control group. PLM data revealed a significantly thicker mineral precipitation band on the surface layer of the GSE-treated lesions when compared to the other groups (p>0.05), which was confirmed by CLSM. We concluded that grape seed extract positively affects the demineralization and/or remineralization processes of artificial root caries lesions, most likely through a different mechanism than that of fluoride. Grape seed extract may be a promising natural agent for non-invasive root caries therapy.

Multi-targeted prevention and therapy of cancer by proanthocyanidins

In recent years, a considerable emphasis has been focused on the importance of the naturally available botanicals that can be consumed in an individual's everyday diet and that can also be useful as a chemopreventive or chemotherapeutic agent for certain diseases, including cancers. A wide variety of botanicals, mostly dietary flavonoids or polyphenolic substances, have been reported to possess substantial anti-carcinogenic and antimutagenic activities because of their antioxidant and anti-inflammatory properties. Proanthocyanidins are considered as one of them, and are abundantly available in various parts of the plants, such as fruits, berries, bark and seeds. Their modes of action were evaluated through a number of in vitro and in vivo studies which showed their potential role as anti-carcinogenic agent. We summarize and highlight the latest developments on anti-carcinogenic activities of proanthocyanidins from different sources, specifically from grape seeds, and their molecular targets, such as NF-kappaB, mitogen-activated protein kinases, PI3K/Akt, caspases, cytokines, angiogenesis and cell cycle regulatory proteins and other check points, etc. Although the bioavailability and metabolism data on proanthocyanidins is still largely unavailable, certain reports indicate that at least monomers and smaller oligomeric procyanidins are absorbed in the gut. The modulation of various molecular targets by proanthocyanidins in vitro and in vivo tumor models suggests their importance, contribution and mechanism of action to the prevention of cancers of different organs.

Safety assessment of pomegranate fruit extract: acute and subchronic toxicity studies

Pomegranate (Punica granatum L.) fruit is widely consumed as fresh fruit and juice. Because of its potential for health benefits, pomegranate fruit extracts have been commonly marketed as dietary supplements in recent years. The objective of the present study was to investigate potential adverse effects, if any, of a standardized pomegranate fruit extract in rats following subchronic administration. The extract was standardized to 30% punicalagins, the active anomeric ellagitannins responsible for over 50% of the antioxidant potential of the juice. The oral LD(50) of the extract in rats and mice was found to be greater than 5 g/kg body weight. The intraperitoneal LD(50) in rats and mice was determined as 217 and 187 mg/kg body weight, respectively. In the subchronic study, Wistar strain rats (10/sex/group) were administered via gavage 0 (control), 60, 240 and 600 mg/kg body weight/day of the extract for 90 days. Two additional groups received 0 and 600 mg/kg/day of the extract for 90 days, followed by a 28 day recovery phase. Compared to the control group, administration of the extract did not result in any toxicologically significant treatment-related changes in clinical observations, ophthalmic examinations, body weights, body weight gains, feed consumption, clinical pathology evaluations and organ weights. The hematology and serum chemistry parameters that showed statistical significant changes compared to control group were within the normal laboratory limits and were considered as biological variations and not the toxic effect of the extract. Terminal necropsy did not reveal any treatment-related gross or histopathology findings. Based on the results of this study, the no observed-adverse-effect level (NOAEL) for this standardized pomegranate fruit extract was determined as 600 mg/kg body weight/day, the highest dose tested.

Flavan-3-ols: nature, occurrence and biological activity

Representing the most common flavonoid consumed in the American diet, the flavan-3-ols and their polymeric condensation products, the proanthocyanidins, are regarded as functional ingredients in various beverages, whole and processed foods, herbal remedies and supplements. Their presence in food affects food quality parameters such as astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and color formation. The ability of flavan-3-ols to aid food functionality has also been established in terms of microbial stability, foamability, oxidative stability, and heat stability. While some foods only contain monomeric flavan-3-ols [(-)-epicatechin predominates] and dimeric proanthocyanidins, most foods contain oligomers of degree of polymerization values ranging from 1-10 or greater than 10. Flavan-3-ols have been reported to exhibit several health beneficial effects by acting as antioxidant, anticarcinogen, cardiopreventive, antimicrobial, anti-viral, and neuro-protective agents. This review summarizes the distribution and health effects of these compounds.