Laboratory and clinical studies of cancer chemoprevention by antioxidants in berries

Black raspberries suppress colonic adenoma development in ApcMin/+ mice: relation to metabolite profiles

Freeze-dried black raspberries (BRBs) have demonstrated chemopreventive effects in a dietary intervention trial with human colorectal cancer patients. The aim of this study was to investigate BRB-caused metabolite changes using the Apc(Min/+) mouse as a model of human colorectal cancer. Wild-type (WT) mice were fed control diet, and Apc(Min/+) mice were fed either control diet or control diet supplemented with 5% BRBs for 8 weeks. Colonic and intestinal polyp size and number were measured. A non-targeted metabolomic analysis was conducted on colonic mucosa, liver and fecal specimens. Eight weeks of BRB treatment significantly decreased intestinal and colonic polyp number and size in Apc(Min/+) mice. The apc gene mutation significantly changed 52 metabolites in colonic mucosa associated with increased amino acid and decreased lipid metabolites, as well as 39 liver and 8 fecal metabolites. BRBs significantly reversed 23 apc-regulated metabolites, including 13 colonic mucosa, 8 liver and 2 fecal metabolites that were involved in amino acid, glutathione, lipid and nucleotide metabolism. Of these, changes in eight metabolites were linearly correlated with decreased colonic polyp number and size in BRB-treated Apc(Min/+) mice. Elevated levels of putrescine and linolenate in Apc(Min/+) mice were significantly decreased by BRBs. Ornithine decarboxylase expression, the key enzyme in putrescine generation, was fully suppressed by BRBs. These results suggest that BRBs produced beneficial effects against colonic adenoma development in Apc(Min/+) mice and modulated multiple metabolic pathways. The metabolite changes produced by BRBs might potentially reflect the BRB-mediated chemopreventive effects in colorectal cancer patients.

Fenretinide Perturbs Focal Adhesion Kinase in Premalignant and Malignant Human Oral Keratinocytes. Fenretinide's Chemopreventive Mechanisms Include ECM Interactions

The membrane-associated protein, focal adhesion kinase (FAK), modulates cell-extracellular matrix interactions and also conveys prosurvival and proliferative signals. Notably, increased intraepithelial FAK levels accompany transformation of premalignant oral intraepithelial neoplasia (OIN) to oral squamous cell carcinoma (OSCC). OIN chemoprevention is a patient-centric, optimal strategy to prevent OSCC's comorbidities and mortality. The cancer chemopreventive and synthetic vitamin A derivative, fenretinide, has demonstrated protein-binding capacities, for example, mTOR- and retinol-binding protein interactions. These studies used a continuum of human oral keratinocytes (normal-HPV E6/E7-transduced-OSCC) to assess potential fenretinide-FAK drug protein interactions and functional consequences on cellular growth regulation and motility. Molecular modeling studies demonstrated that fenretinide has approximately 200-fold greater binding affinity relative to the natural ligand (ATP) at FAK's kinase domain. Fenretinide also shows intermediate binding at FAK's FERM domain and interacts at the ATP-binding site of the closest FAK analogue, PYK2. Fenretinide significantly suppressed proliferation via induction of apoptosis and G2-M cell-cycle blockade. Fenretinide-treated cells also demonstrated F-actin disruption, significant inhibition of both directed migration and invasion of a synthetic basement membrane, and decreased phosphorylation of growth-promoting kinases. A commercially available FAK inhibitor did not suppress cell invasion. Notably, although FAK's FERM domain directs cell invasion, FAK inhibitors target the kinase domain. In addition, FAK-specific siRNA-treated cells showed an intermediate cell migration capacity; data which suggest cocontribution of the established migrating-enhancing PYK2. Our data imply that fenretinide is uniquely capable of disrupting FAK's and PYK2's prosurvival and mobility-enhancing effects and further extend fenretinide's chemopreventive contributions beyond induction of apoptosis and differentiation.

A Perspective on Prostate Carcinogenesis and Chemoprevention

In this perspective, modifiable carcinogenic factors for the prostate are summarized. This is followed by a discussion of how current knowledge about causation of prostate cancer and chemoprevention of prostate cancer can be used to develop preventive strategies. Prostate cancer is a slowly developing cancer which offers opportunities for preventive interventions. Only a few randomized clinical trials of prostate cancer prevention have been completed. The SELECT study with selenium and vitamin E did not find protective effects, but in two trials with 5α-reductase inhibitors risk was reduced about 25%, showing that chemoprevention is possible and indicating that the androgen receptor is a suitable target. Besides smoking cessation and reduction of obesity, there are no known dietary or life style interventions that will have a major impact on prostate cancer risk. Inflammation of the prostate is an attractive target and aspirin may be a promising candidate agent, but has not been addressed yet in preclinical and clinical studies. Antioxidants other than selenium and vitamin E are unlikely to be very effective and data on several dietary supplements are not encouraging. More candidate agents need to be identified and tested in relevant and adequate preclinical models and Phase II trials that have predictive value for outcome of Phase III randomized studies. Doing this will require a systematic approach comparing preclinical and clinical study outcomes to determine their predictive value of preventive efficacy.

Antiproliferative and antioxidant properties of anthocyanin rich extracts from blueberry and blackcurrant juice

The present study was aimed at evaluating the antiproliferative potential of anthocyanin-rich fractions (ARFs) obtained from two commercially available juices (blueberry and blackcurrant juices) on three tumor cell lines; B16F10 (murine melanoma), A2780 (ovarian cancer) and HeLa (cervical cancer). Individual anthocyanin determination, identification and quantification were done using HPLC-MS. Antioxidant activity of the juices was determined through different mechanism methods such as DPPH and ORAC. For biological testing, the juices were purified through C18 cartridges in order to obtain fractions rich in anthocyanins. The major anthocyanins identified were glycosylated cyanidin derivatives. The antiproliferative activity of the fractions was tested using the MTT assay. The antiproliferative potential of ARF was found to be associated with those bioactive molecules, anthocyanins due to their antioxidant potential. The results obtained indicated that both blueberry and blackcurrants are rich sources of antioxidants including anthocyanins and therefore these fruits are highly recommended for daily consumption to prevent numerous degenerative diseases.

Strawberry as a health promoter: an evidence based review

The health effects of strawberry bioactive compounds depend on the activation and modulation of several genetic and molecular mechanisms.

Chemoprevention of oral cancer by topical application of black raspberries on high at-risk mucosa

OBJECTIVE

To evaluate the preclinical efficacy of topical administration of freeze-dried black raspberries (BRBs) to inhibit the progression of premalignant oral lesions and modulate biomarkers of cancer development in high at-risk mucosa (HARM).

STUDY DESIGN

Hamster cheek pouches (HCPs) were treated with carcinogen for 6 weeks to initiate a HARM microenvironment. Subsequently, right HCPs were topically administered a BRB suspension in short-term or long-term studies. After 12 weeks, squamous cell carcinoma (SCC) multiplicity, SCC incidence, and cell proliferation rates were evaluated. mRNA expression was measured in short-term treated pouches for selected oral cancer biomarkers.

RESULTS

SCC multiplicity (-41.3%), tumor incidence (-37.1%), and proliferation rate (-6.9%) were reduced in HCPs receiving BRBs. Topical BRBs correlated with an increase in RB1 expression in developing oral lesions.

CONCLUSIONS

Topical BRBs inhibit SCC development when targeted to HARM tissues. These results support the translational role of BRBs to prevent oral cancer development in humans.

Effect of curcumin on hepatic heme oxygenase 1 expression in high fat diet fed rats: is there a triangular relationship?

High fat diet (HFD) is associated with oxidative stress induced fatty liver. Curcumin, an extract of Curcuma longa, has been shown to possess potent antioxidant and hypolipidemic properties. In this study, we investigated the effect of curcumin treatment on hepatic heme oxygenase-1 (HO-1) expression along with pro-oxidant-antioxidant status and lipid accumulation in rats fed an HFD. Male Sprague-Dawley rats were distributed among 4 groups: Group 1, which was fed the control diet (10% of total calories from fat); Group 2, which was fed the HFD (60% of total calories from fat); and groups 3 and 4, which received the HFD supplemented with curcumin and the control diet supplemented with curcumin (1 g/kg diet; w/w), respectively, for 16 weeks. HFD caused increases in hepatic lipid levels, production of reactive oxygen species, and lipid peroxidation. Further, HO-1 expression was significantly decreased. Histopathological examination showed hepatic fat accumulation and slight fibrotic changes. Curcumin treatment reduced hepatic lipids and oxidative stress parameters, and HO-1 expression was significantly increased. These findings suggest that increased HO-1 expression, along with suppressed oxidative stress as well as reduced hepatic fat accumulation and fibrotic changes, contribute to the beneficial effects of curcumin in attenuating the pathogenesis of fatty liver induced metabolic diseases.

The berry constituents quercetin, kaempferol, and pterostilbene synergistically attenuate reactive oxygen species: involvement of the Nrf2-ARE signaling pathway

Quercetin, kaempferol, and pterostilbene are abundant in berries. The anti-oxidative properties of these constituents may contribute to cancer chemoprevention. However, their precise mechanisms of action and their combinatorial effects are not completely understood. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) regulates anti-oxidative stress enzymes and Phase II drug metabolizing/detoxifying enzymes by binding to antioxidant response element (ARE). This study aimed to investigate the anti-oxidative stress activities of quercetin, kaempferol, and pterostilbene individually and in combination, as well as the involvement of the Nrf2-ARE signaling pathway. Quercetin, kaempferol, and pterostilbene all exhibited strong free-radical scavenging activity in the DPPH assay. The MTS assay revealed that low concentration combinations we tested were relatively non-toxic to HepG2-C8 cells. The results of the DCFH-DA assay and combination index (CI) indicated that quercetin, kaempferol, and pterostilbene attenuated intracellular reactive oxygen species (ROS) levels when pretreated individually and had synergistic effects when used in combination. In addition, the combination treatment significantly induced ARE and increased the mRNA and protein expression of Nrf2-regulated genes. Collectively, our study demonstrated that the berry constituents quercetin, kaempferol, and pterostilbene activated the Nrf2-ARE signaling pathway and exhibited synergistic anti-oxidative stress activity at appropriate concentrations.

A Phytochemical-rich Multivitamin-multimineral Supplement Is Bioavailable and Reduces Serum Oxidized Low-density Lipoprotein, Myeloperoxidase, and Plasminogen Activator Inhibitor-1 in a Four-week Pilot trial of Healthy Individuals

BACKGROUND

A multivitamin-multimineral supplement combined with a diverse blend of bioactive phytochemicals may provide additional antioxidant capacity and anti-inflammatory property for overall health. This convenient feature may be useful for individuals who want to increase their intake of phytochemicals.

METHODS

We conducted a pilot study in 15 healthy individuals (8 women and 7 men, mean age 41.7±14.9 years, mean body mass index 28.0±5.6) to investigate the effects of this novel formulation on biomarkers associated with oxidative stress and inflammation. After a 2-week diet that limited intake of fruits and vegetables to 2 servings/day, participants continued with the same restricted diet but began consuming 2 tablets of the study product for the subsequent 4 weeks. Fasting blood samples collected at Week 2 and Week 6 were analyzed and compared using paired t-tests for levels of carotenoids, folate, vitamin B12, homocysteine, oxidized low-density lipoprotein cholesterol (oxLDL), high-sensitivity C-reactive protein (hs-CRP), F2-isoprostane, plasminogen activator inhibitor-1 (PAI-1), and myeloperoxidase. Noninvasive peripheral arterial tonometry (EndoPAT) was also measured.

RESULTS

After 4 weeks of supplementation, plasma levels of carotenoids, folate, and vitamin B12, but not homocysteine, were significantly increased (P<.05). Serum levels of oxLDL, PAI-1 and myeloperoxidase were significantly reduced (P<.05), but F2-isoprostane, hs-CRP, and EndoPAT measures were unchanged compared with baseline. The study product was well tolerated.

CONCLUSIONS

This nutritional supplement is bioavailable as indicated by the significant increase in plasma carotenoids, vitamin B12, and folate levels and may provide health benefits by significantly reducing serum levels of oxLDL, myeloperoxidase, and PAI-1 in healthy individuals.

Strawberry and human health: effects beyond antioxidant activity

The usefulness of a diet rich in vegetables and fruits on human health has been widely recognized: a high intake of antioxidant and bioactive compounds may in fact play a crucial role in the prevention of several diseases, such as cancer, cardiovascular, neurodegenerative, and other chronic pathologies. The strawberry (Fragaria × ananassa Duch.) possesses a remarkable nutritional composition in terms of micronutrients, such as minerals, vitamin C, and folates, and non-nutrient elements, such as phenolic compounds, that are essential for human health. Although strawberry phenolics are known mainly for their anti-inflammatory and antioxidant actions, recent studies have demonstrated that their biological activities also spread to other pathways involved in cellular metabolism and cellular survival. This paper has the main objective of reviewing current information about the potential mechanisms involved in the effects elicited by strawberry polyphenols on human health, devoting special attention to the latest findings.

The choice of reference gene affects statistical efficiency in quantitative PCR data analysis

Quantitative polymerase chain reaction (qPCR), a highly sensitive method of measuring gene expression, is widely used in biomedical research. To produce reliable results, it is essential to use stably expressed reference genes (RGs) for data normalization so that sample-to-sample variation can be controlled. In this study, we examine the effect of different RGs on statistical efficiency by analyzing a qPCR data set that contains 12 target genes and 3 RGs. Our results show that choosing the most stably expressed RG for data normalization does not guarantee reduced variance or improved statistical efficiency. We also provide a formula for determining when data normalization will improve statistical efficiency and hence increase the power of statistical tests in data analysis.

Contribution of organically grown crops to human health

An increasing interest in organic agriculture for food production is seen throughout the world and one key reason for this interest is the assumption that organic food consumption is beneficial to public health. The present paper focuses on the background of organic agriculture, important public health related compounds from crop food and variations in the amount of health related compounds in crops. In addition, influence of organic farming on health related compounds, on pesticide residues and heavy metals in crops, and relations between organic food and health biomarkers as well as in vitro studies are also the focus of the present paper. Nutritionally beneficial compounds of highest relevance for public health were micronutrients, especially Fe and Zn, and bioactive compounds such as carotenoids (including pro-vitamin A compounds), tocopherols (including vitamin E) and phenolic compounds. Extremely large variations in the contents of these compounds were seen, depending on genotype, climate, environment, farming conditions, harvest time, and part of the crop. Highest amounts seen were related to the choice of genotype and were also increased by genetic modification of the crop. Organic cultivation did not influence the content of most of the nutritional beneficial compounds, except the phenolic compounds that were increased with the amounts of pathogens. However, higher amounts of pesticide residues and in many cases also of heavy metals were seen in the conventionally produced crops compared to the organic ones. Animal studies as well as in vitro studies showed a clear indication of a beneficial effect of organic food/extracts as compared to conventional ones. Thus, consumption of organic food seems to be positive from a public health point of view, although the reasons are unclear, and synergistic effects between various constituents within the food are likely.

Dichotomous effect of caffeine, curcumin, and naringenin on genomic DNA of normal and diabetic subjects

Nutraceutical compounds show antioxidant and prooxidant properties under stress conditions like cancer, diabetes, and other diseases. The objective of this study is to find the dichotomic behavior of caffeine, curcumin, and naringenin on DNA of diabetic and normal subjects in the presence and absence of copper, hydrogen peroxide, and complex of copper-hydrogen peroxide. Hydrogen peroxide releases hydroxyl free radicals ((•)OH) on oxidation of Cu (I) to Cu (II) through Fenton-type reaction to cause DNA damage. In the results, agarose gel electrophoretic pattern speculates the prooxidant effect of caffeine and antioxidant effect of curcumin on DNA in the presence of copper and hydrogen peroxide. UV-Vis spectral analysis shows hyperchromism on addition of DNA to caffeine, hypochromism with curcumin, and subtle changes with naringenin. The chosen nutraceuticals act as inducers and quenchers of oxidative free radicals arising from diabetes.

Polyphenols pattern and correlation with antioxidant activities of berries extracts from four different populations of Sicilian Sambucus nigra L

Sambucus nigra L. (Caprifoliaceae) is wide spread in temperate and sub-tropical zones. The consumption of its berries has been associated with health benefits especially for its high content of natural antioxidants such as polyphenols, in particular anthocyanins. In this work we investigated the polyphenolic composition and the in vitro antioxidant activities (ABTS, DPPH, BCB and FRAP-ferrozine (FRAP-FZ) assays) of S. nigra berries, collected in four different Sicilian areas (Italy). Elderberries are considered one of the fruits with highest anthocyanins content, the amount of phenolic compounds, other than anthocyanins, is approximately 1.5 times greater than the latter. The LC-MS analyses have revealed an opposite trend in the polyphenols pattern in Sicilian populations. Moreover, a statistical correlation was found between cyanidin-3-sambubioside-5-glucoside and antioxidant activity evaluated by FRAP-FZ and ABTS assays. In conclusion, Sicilian S. nigra berries are appealing for its antioxidant potential and for its particularly high content of anthocyanins.

NMR-based metabolomic investigation of bioactivity of chemical constituents in black raspberry (Rubus occidentalis L.) fruit extracts

Black raspberry (Rubus occidentalis L.) (BR) fruit extracts with differing compound profiles have shown variable antiproliferative activities against HT-29 colon cancer cell lines. This study used partial least-squares (PLS) regression analysis to develop a high-resolution (1)H NMR-based multivariate statistical model for discerning the biological activity of BR constituents. This model identified specific bioactive compounds and ascertained their relative contribution against cancer cell proliferation. Cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside were the predominant contributors to the extract bioactivity, but salicylic acid derivatives (e.g., salicylic acid glucosyl ester), quercetin 3-glucoside, quercetin 3-rutinoside, p-coumaric acid, epicatechin, methyl ellagic acid derivatives (e.g., methyl ellagic acetyl pentose), and citric acid derivatives also contributed significantly to the antiproliferative activity of the berry extracts. This approach enabled the identification of new bioactive components in BR fruits and demonstrates the utility of the method for assessing chemopreventive compounds in foods and food products.

Topical application of a mucoadhesive freeze-dried black raspberry gel induces clinical and histologic regression and reduces loss of heterozygosity events in premalignant oral intraepithelial lesions: results from a multicentered, placebo-controlled clinical trial

PURPOSE

Approximately 30% higher grade premalignant oral intraepithelial neoplasia (OIN) lesions will progress to oral cancer. Although surgery is the OIN treatment mainstay, many OIN lesions recur, which is highly problematic for both surgeons and patients. This clinical trial assessed the chemopreventive efficacy of a natural product-based bioadhesive gel on OIN lesions.

EXPERIMENTAL DESIGN

This placebo-controlled multicenter study investigated the effects of topical application of bioadhesive gels that contained either 10% w/w freeze-dried black raspberries (BRB) or an identical formulation devoid of BRB placebo to biopsy-confirmed OIN lesions (0.5 g × q.i.d., 12 weeks). Baseline evaluative parameters (size, histologic grade, LOH events) were comparable in the randomly assigned BRB (n = 22) and placebo (n = 18) gel cohorts. Evaluative parameters were: histologic grade, clinical size, and LOH.

RESULTS

Topical application of the BRB gel to OIN lesions resulted in statistically significant reductions in lesional sizes, histologic grades, and LOH events. In contrast, placebo gel lesions demonstrated a significant increase in lesional size and no significant effects on histologic grade or LOH events. Collectively, these data strongly support BRB's chemopreventive impact. A cohort of very BRB-responsive patients, as demonstrated by high therapeutic efficacy, was identified. Corresponding protein profiling studies, which demonstrated higher pretreatment levels of BRB metabolic and keratinocyte differentiation enzymes in BRB-responsive lesions, reinforce the importance of local metabolism and differentiation competency.

CONCLUSIONS

Results from this trial substantiate the LOH reductions identified in the pilot BRB gel study and extend therapeutic effects to significant improvements in histologic grade and lesional size.

Antidiabetic potential of the heme oxygenase-1 inducer curcumin analogues

Although there is a therapeutic treatment to combat diabetes, the identification of agents that may deal with its more serious aspects is an important medical field for research. Diabetes, which contributes to the risk of cardiovascular disease, is associated with a low-grade chronic inflammation (inflammatory stress), oxidative stress, and endoplasmic reticulum (ER) stress. Because the integration of these stresses is critical to the pathogenesis of diabetes, agents and cellular molecules that can modulate these stress responses are emerging as potential targets for intervention and treatment of diabetic diseases. It has been recognized that heme oxygenase-1 (HO-1) plays an important role in cellular protection. Because HO-1 can reduce oxidative stress, inflammatory stress, and ER stress, in part by exerting antioxidant, anti-inflammatory, and antiapoptotic effects, HO-1 has been suggested to play important roles in pathogenesis of diabetes. In the present review, we will explore our current understanding of the protective mechanisms of HO-1 in diabetes and present some emerging therapeutic options for HO-1 expression in treating diabetic diseases, together with the therapeutic potential of curcumin analogues that have their ability to induce HO-1 expression.

Therapeutic roles of heme oxygenase-1 in metabolic diseases: curcumin and resveratrol analogues as possible inducers of heme oxygenase-1

Metabolic diseases, such as insulin resistance, type II diabetes, and obesity, are associated with a low-grade chronic inflammation (inflammatory stress), oxidative stress, and endoplasmic reticulum (ER) stress. Because the integration of these stresses is critical to the pathogenesis of metabolic diseases, agents and cellular molecules that can modulate these stress responses are emerging as potential targets for intervention and treatment of metabolic diseases. It has been recognized that heme oxygenase-1 (HO-1) plays an important role in cellular protection. Because HO-1 can reduce inflammatory stress, oxidative stress, and ER stress, in part by exerting antioxidant, anti-inflammatory, and antiapoptotic effects, HO-1 has been suggested to play important roles in pathogenesis of metabolic diseases. In the present review, we will explore our current understanding of the protective mechanisms of HO-1 in metabolic diseases and present some emerging therapeutic options for HO-1 expression in treating metabolic diseases, together with the therapeutic potential of curcumin and resveratrol analogues that have their ability to induce HO-1 expression.

Contributions of phenolics and added vitamin C to the antioxidant capacity of pomegranate and grape juices: synergism and antagonism among constituents

The aim of this study was to examine the contribution of sugar, organic acid, neutral phenol, and anthocyanin fractions and added ascorbic acid to grape and pomegranate-nectarine juice total phenol, ORAC, FRAP, and DPPH values. Neutral phenol and anthocyanin fractions contributed ≥75% of the total antioxidant capacity (TAC) for both juices. Intrinsic synergy and antagonism among the fractionated constituents occurred inconsistently in each assay. Sugars and organic acids antagonized pomegranate juice neutral phenols and anthocyanins in the DPPH assay by 50% and the grape juice ORAC value by 21%, but were synergistic to the grape juice FRAP value. The added ascorbic acid was dose-dependently synergistic with pomegranate and grape juice total phenol, DPPH, and FRAP assays, but less so in the ORAC assay. Thus, the interactions between grape and pomegranate juice constituents determine TAC and total phenol values, and synergy in these assays could not be attributed solely to polyphenols.

Protective effect of tropical highland blackberry juice (Rubus adenotrichos Schltdl.) against UVB-mediated damage in human epidermal keratinocytes and in a reconstituted skin equivalent model

Solar ultraviolet (UV) radiation, particularly its UVB (280-320 nm) spectrum, is the primary environmental stimulus leading to skin carcinogenesis. Several botanical species with antioxidant properties have shown photochemopreventive effects against UVB damage. Costa Rica's tropical highland blackberry (Rubus adenotrichos) contains important levels of phenolic compounds, mainly ellagitannins and anthocyanins, with strong antioxidant properties. In this study, we examined the photochemopreventive effect of R. adenotrichos blackberry juice (BBJ) on UVB-mediated responses in human epidermal keratinocytes and in a three-dimensional (3D) reconstituted normal human skin equivalent (SE). Pretreatment (2 h) and posttreatment (24 h) of normal human epidermal keratinocytes (NHEKs) with BBJ reduced UVB (25 mJ cm(-2))-mediated (1) cyclobutane pyrimidine dimers (CPDs) and (2) 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation. Furthermore, treatment of NHEKs with BBJ increased UVB-mediated (1) poly(ADP-ribose) polymerase cleavage and (2) activation of caspases 3, 8 and 9. Thus, BBJ seems to alleviate UVB-induced effects by reducing DNA damage and increasing apoptosis of damaged cells. To establish the in vivo significance of these findings to human skin, immunohistochemistry studies were performed in a 3D SE model, where BBJ was also found to decrease CPDs formation. These data suggest that BBJ may be developed as an agent to ameliorate UV-induced skin damage.

Assessment of genotoxicity and antigenotoxicity of an aqueous extract of Cleistocalyx nervosum var. paniala in in vitro and in vivo models

Cleistocalyx nervosum var. paniala, an edible fruit found in Northern Thailand, contains high amounts of phenolic compounds with in vitro antioxidant activity. The aqueous extract of the ripe fruit was evaluated for its safety and beneficial effects using genotoxicity and toxicity tests. The C. nervosum extract was not only non-mutagenic in Salmonella typhimurium strains TA98 and TA100 in the presence and absence of metabolic activation, but exhibited also moderate antimutagenic effects against aflatoxin B1 and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline-induced mutagenesis. Electrospray ionization-mass spectrometric analysis revealed the major anthocyanins, which included cyanidin-3,5-diglucoside, cyanidin-3-glucoside and cyanidin-5-glucoside. The administration of C. nervosum at concentration of 5,000 mg/kg bw did not induce acute toxicity in rats. A liver micronucleus test was performed to detect clastogenicity and anticlastogenicity. The extract in the dose of 1,000 mg/kg did not cause micronucleus formation in the liver of rats. Furthermore, in rats administered 100-1,000 mg/kg of the extract, no anticlastogenic effect against diethylnitrosamine-induced hepatic micronucleus formation was observed. These studies provide data concerning the safety and antimutagenic potency of an aqueous extract of C. nervosum fruit.

Inhibition of lung tumor development by berry extracts in mice exposed to cigarette smoke

Cigarette smoke (CS) and dietary factors play a major role in cancer epidemiology. At the same time, however, the diet is the richest source of anticancer agents. Berries possess a broad array of health protective properties and were found to attenuate the yield of tumors induced by individual carcinogens in the rodent digestive tract and mammary gland but failed to prevent lung tumors induced by typical CS components in mice. We exposed whole-body Swiss ICR mice to mainstream CS, starting at birth and continuing daily for 4 months. Aqueous extracts of black chokeberry and strawberry were given as the only source of drinking water, starting after weaning and continuing for 7 months, thus mimicking an intervention in current smokers. In the absence of berries, CS caused a loss of body weight, induced early cytogenetical damage in circulating erythrocytes and histopathological alterations in lung (emphysema, blood vessel proliferation, alveolar epithelial hyperplasia and adenomas), liver (parenchymal degeneration) and urinary bladder (epithelial hyperplasia). Both berry extracts inhibited the CS-related body weight loss, cytogenetical damage, liver degeneration, pulmonary emphysema and lung adenomas. Protective effects were more pronounced in female mice, which may be ascribed to modulation by berry components of the metabolism of estrogens implicated in lung carcinogenesis. Interestingly, both the carcinogen and the chemopreventive agents tested are complex mixtures that contain a multitude of components working through composite mechanisms.

Oxidative stress in older adults: effects of physical fitness

Acute exercise results in transient change in redox balance. High concentrations of reactive oxygen species (ROS) can lead to oxidative damage to macromolecules. However, moderate periodic increases in ROS, such as experienced with habitual exercise, may activate signal transduction pathways which stimulate increases in endogenous antioxidant systems. This study tested the hypothesis that physically fit older adults would have less oxidative stress than unfit age-matched controls, due to greater circulating concentrations of non-enzymatic antioxidants and greater capacity to upregulate antioxidant enzymes. We compared 37 fit (mean age 65.2 ± 5 years) and 35 unfit (mean age 67.7 ± 4 years) men and women. Fitness status was classified by VO(2 max) and maximal leg power. Basal levels of oxidative stress were assessed by measuring urinary markers of nucleic acid damage and lipid peroxidation. Antioxidant status was assessed by measuring total antioxidant power and ratios of reduced to oxidized glutathione in plasma, at rest. The capacity to counteract an oxidative insult was assessed by measuring changes in plasma F(2)-isoprostanes in response to forearm ischemia-reperfusion. The fit individuals had significantly lower levels of urinary markers of oxidative damage (all P <0.05) and lower F(2)-isoprostane response to the oxidative challenge (P < 0.05), but there were no group differences in antioxidant status. The lower levels of oxidative stress in the fit individuals were not mediated by known effects of exercise training such as adiposity, HDL concentrations, or small molecular weight antioxidants. These data suggest that reduced oxidative stress associated with physical fitness results from differences in activity of antioxidant enzymes.

Plasma cytokines as potential response indicators to dietary freeze-dried black raspberries in colorectal cancer patients

Oral consumption of freeze-dried black raspberries attenuated neoplastic changes in colorectal tissue markers of apoptosis, cell proliferation, and angiogenesis in colorectal cancer (CRC) patients. To determine whether plasma concentrations of interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, IL-12p70, granulocyte macrophage colony stimulating factor (GM-CSF), interferon-γ, and tumor necrosis factor-α (TNF-α) were associated with berry treatment and changes in colorectal tissue markers of apoptosis, cell proliferation, and angiogenesis, plasma and biopsy samples of adenocarcinoma and adjacent normal-appearing colorectal tissue were collected before and during berry treatment from 24 CRC patients who had not received prior therapy and drank a slurry of black raspberry powder (20 g in 100 ml drinking water) 3 times a day for 1 to 9 wk. Plasma concentrations of GM-CSF (+0.12 ± 0.04 pg/mL; P = 0.01) and IL-8 (-1.61 ± 0.71 pg/mL; P = 0.04) changed in patients receiving berries for more than 10 days. These changes were correlated with beneficial changes in markers of proliferation (r(ΔGM-CSF, ΔKi67 carcinoma - normal) = -0.51) and apoptosis (r(ΔIL-8, ΔTUNEL carcinoma - normal) = -0.52) observed in colorectal tissue taken within the same week. Plasma concentrations of GM-CSF and IL-8 may serve as noninvasive indicators to monitor tissue response to berry-based interventions for CRC.

The strawberry: composition, nutritional quality, and impact on human health

Strawberries are a common and important fruit in the Mediterranean diet because of their high content of essential nutrients and beneficial phytochemicals, which seem to have relevant biological activity in human health. Among these phytochemicals, anthocyanin and ellagitannins are the major antioxidant compounds. Although individual phytochemical constituents of strawberries have been studied for their biological activities, human intervention studies using whole fruits are still lacking. Here, the nutritional contribution and phytochemical composition of the strawberry are reviewed, as is the role played by the maturity, genotype, and storage effects on this fruit. Specific attention is focused on fruit absorption, metabolism, and the possible beneficial biological activity on human health.

Assay dilution factors confound measures of total antioxidant capacity in polyphenol-rich juices

The extent to which sample dilution factor (DF) affects total antioxidant capacity (TAC) values is poorly understood. Thus, we examined the impact of DF on the ORAC, FRAP, DPPH, and total phenols (TP) assays using pomegranate juice (PJ), grape juice (GJ), selected flavonoids, ascorbic acid, and ellagic acid. For ORAC, GJ was comparable to PJ at DF 750, but at DF 2000, the ORAC value of GJ was 40% more than PJ. Increasing DF increased GJ and PJ, DPPH, TP, and FRAP values 11% and 14%, respectively. Increased test concentrations of quercetin and catechin resulted in 51% and 126% greater ORAC values, but decreased naringenin by 68%. Flavonoids, but not ellagic acid or ascorbic acid, may contribute to the dilution effect on the variation of final TAC values. Thus, reporting TAC or TP using a single DF may introduce uncertainty about the confidence of TAC assay values, especially when comparing different juices. These results underscore the importance of using compatible test standards for reporting TAC values.

PRACTICAL APPLICATION

Total antioxidant capacity (TAC) values such as the ORAC assay are increasingly used for comparison of polyphenol-rich foods and beverages. Choice of standards and test concentrations, even within the linear range of standards, may introduce variation probably due to synergy/antagonism between antioxidant and thereby, confound final TAC values. Thus, test concentration or dilution factors of samples should be considered in the design of TAC assays and interpretation of their results.

Physical activity and nutrition attitudes in obese Hispanic children with non-alcoholic steatohepatitis

AIM: To assess nutrition, physical activity and healthful knowledge in obese children with biopsy-proven non-alcoholic steatohepatitis (NASH or NA) compared to children without liver disease.

METHODS: Children with biopsy-proven NASH comprised the NASH group. Age, sex and ethnicity matched control groups consisted of obese (OB) and lean (CO) children with no liver disease. Subjects were administered the School Physical Activity and Nutrition Survey and one blood draw was obtained.

RESULTS: Fifty-seven patients were enrolled with a mean age of 12.1 ± 2.1 years, and all were Hispanic. Even though the OB and NA had a similar increased body mass index (%), 35% of the NA group always read nutrition labels compared to none in the OB (P < 0.05), and more NA children felt their diet is “less healthy”. NA consumed the least amount of fruits with only 25% having ≥ 1 fruit/d vs 45% in OB and 64.7% in CO (P < 0.05 NA vs CO). Only 15% of NA subjects performed light exercise vs 35% and 59% of OB and CO groups, respectively (P = 0.02). The mean physical activity score was lowest in the NA group (P < 0.05). Amongst the subjects with NASH, we found that 100% of patients with grade 2 or 3 fibrosis had a sedentary score > 2 compared to only 63.6% of those with grade 1 or no fibrosis (P < 0.05).

CONCLUSION: Children with NASH had increased se-dentary behavior, decreased activity, and fruit intake. Larger studies may determine the benefit of changing these behaviors as treatment for NASH.

Optimizing therapeutic efficacy of chemopreventive agents: A critical review of delivery strategies in oral cancer chemoprevention clinical trials

Due to its characterized progression from recognized premalignant oral epithelial changes (i.e., oral epithelial dysplasia) to invasive cancer, oral squamous cell carcinoma represents an optimal disease for chemopreventive intervention prior to malignant transformation. The primary goal of oral cancer chemoprevention is to reverse, suppress, or inhibit the progression of premalignant lesions to cancer. Over the last several decades, numerous oral cancer chemoprevention clinical trials have assessed the therapeutic efficacy of diverse chemopreventive agents. The standard of care for more advanced oral dysplastic lesions entails surgical excision and close clinical follow-up due to the potential (~33%) for local recurrence at a similar or more advanced histological stage. The purpose of this review was to identify prominent oral cancer chemoprevention clinical trials, assess their overall therapeutic efficacy, and delineate effects of local versus systemic drug administration. In addition, these compiled clinical trial data present concepts for consideration in the design and conduction of future clinical trials.

Oxidative stress and therapeutic opportunities: focus on the Ewing's sarcoma family of tumors

Reactive oxygen species (ROS) are highly reactive by-products of energy production that can have detrimental as well as beneficial effects. Unchecked, high levels of ROS result in an imbalance of cellular redox state and oxidative stress. High levels of ROS have been detected in most cancers, where they promote tumor development and progression. Many anticancer agents work by further increasing cellular levels of ROS, to overcome the antioxidant detoxification capacity of the cancer cell and induce cell death. However, adaptation of the level of cellular antioxidants can lead to drug resistance. The challenge for the design of effective cancer therapeutics exploiting oxidative stress is to tip the cellular redox balance to induce ROS-dependent cell death but without increasing the antioxidant activity of the cancer cell or inducing toxicity in normal cells.

Clinical trials of antioxidants as cancer prevention agents: past, present, and future

The purpose of this review is to summarize the most important human clinical trials of antioxidants as cancer prevention agents conducted to date, provide an overview of currently ongoing studies, and discuss future steps needed to advance research in this field. To date there have been several large (at least 7000 participants) trials testing the efficacy of antioxidant supplements in preventing cancer. The specific agents (diet-derived direct antioxidants and essential components of antioxidant enzymes) tested in those trials included β-carotene, vitamin E, vitamin C, selenium, retinol, zinc, riboflavin, and molybdenum. None of the completed trials produced convincing evidence to justify the use of traditional antioxidant-related vitamins or minerals for cancer prevention. Our search of ongoing trials identified six projects at various stages of completion. Five of those six trials use selenium as the intervention of interest delivered either alone or in combination with other agents. The lack of success to date can be explained by a variety of factors that need to be considered in the next generation research. These factors include lack of good biological rationale for selecting specific agents of interest; limited number of agents tested to date; use of pharmacological, rather than dietary, doses; and insufficient duration of intervention and follow-up. The latter consideration underscores the need for alternative endpoints that are associated with increased risk of neoplasia (i.e., biomarkers of risk), but are detectable prior to tumor occurrence. Although dietary antioxidants are a large and diverse group of compounds, only a small proportion of candidate agents have been tested. In summary, the strategy of focusing on large high-budget studies using cancer incidence as the endpoint and testing a relatively limited number of antioxidant agents has been largely unsuccessful. This lack of success in previous trials should not preclude us from seeking novel ways of preventing cancer by modulating oxidative balance. On the contrary, the well demonstrated mechanistic link between excessive oxidative stress and carcinogenesis underscores the need for new studies. It appears that future large-scale projects should be preceded by smaller, shorter, less expensive biomarker-based studies that can serve as a link from mechanistic and observational research to human cancer prevention trials. These relatively inexpensive studies would provide human experimental evidence for the likely efficacy, optimum dose, and long-term safety of the intervention of interest that would then guide the design of safe, more definitive large-scale trials.

Polycyclic aromatic hydrocarbon (PAH) exposure and DNA adduct semi-quantitation in archived human tissues

Polycyclic aromatic hydrocarbons (PAHs) are combustion products of organic materials, mixtures of which contain multiple known and probable human carcinogens. PAHs occur in indoor and outdoor air, as well as in char-broiled meats and fish. Human exposure to PAHs occurs by inhalation, ingestion and topical absorption, and subsequently formed metabolites are either rendered hydrophilic and excreted, or bioactivated and bound to cellular macromolecules. The formation of PAH-DNA adducts (DNA binding products), considered a necessary step in PAH-initiated carcinogenesis, has been widely studied in experimental models and has been documented in human tissues. This review describes immunohistochemistry (IHC) studies, which reveal localization of PAH-DNA adducts in human tissues, and semi-quantify PAH-DNA adduct levels using the Automated Cellular Imaging System (ACIS). These studies have shown that PAH-DNA adducts concentrate in: basal and supra-basal epithelium of the esophagus, cervix and vulva; glandular epithelium of the prostate; and cytotrophoblast cells and syncitiotrophoblast knots of the placenta. The IHC photomicrographs reveal the ubiquitous nature of PAH-DNA adduct formation in human tissues as well as PAH-DNA adduct accumulation in specific, vulnerable, cell types. This semi-quantative method for PAH-DNA adduct measurement could potentially see widespread use in molecular epidemiology studies.

Supplementation of a western diet with golden kiwifruits (Actinidia chinensis var.'Hort 16A':) effects on biomarkers of oxidation damage and antioxidant protection

BACKGROUND

The health positive effects of diets high in fruits and vegetables are generally not replicated in supplementation trials with isolated antioxidants and vitamins, and as a consequence the emphasis of chronic disease prevention has shifted to whole foods and whole food products.

METHODS

We carried out a human intervention trial with the golden kiwifruit, Actinidia chinensis, measuring markers of antioxidant status, DNA stability, plasma lipids, and platelet aggregation. Our hypothesis was that supplementation of a normal diet with kiwifruits would have an effect on biomarkers of oxidative status. Healthy volunteers supplemented a normal diet with either one or two golden kiwifruits per day in a cross-over study lasting 2 × 4 weeks. Plasma levels of vitamin C, and carotenoids, and the ferric reducing activity of plasma (FRAP) were measured. Malondialdehyde was assessed as a biomarker of lipid oxidation. Effects on DNA damage in circulating lymphocytes were estimated using the comet assay with enzyme modification to measure specific lesions; another modification allowed estimation of DNA repair.

RESULTS

Plasma vitamin C increased after supplementation as did resistance towards H₂O₂-induced DNA damage. Purine oxidation in lymphocyte DNA decreased significantly after one kiwifruit per day, pyrimidine oxidation decreased after two fruits per day. Neither DNA base excision nor nucleotide excision repair was influenced by kiwifruit consumption. Malondialdehyde was not affected, but plasma triglycerides decreased. Whole blood platelet aggregation was decreased by kiwifruit supplementation.

CONCLUSION

Golden kiwifruit consumption strengthens resistance towards endogenous oxidative damage.

Analysis of anthocyanins in commercial fruit juices by using nano-liquid chromatography-electrospray-mass spectrometry and high-performance liquid chromatography with UV-vis detector

Nano-LC and conventional HPLC techniques were applied for the analysis of anthocyanins present in commercial fruit juices using a capillary column of 100 μm id and a 2.1 mm id narrow-bore C(18) column. Analytes were detected by UV-Vis at 518 nm and ESI-ion trap MS with HPLC and nano-LC, respectively. Commercial blueberry juice (14 anthocyanins detected) was used to optimize chromatographic separation of analytes and other analysis parameters. Qualitative identification of anthocyanins was performed by comparing the recorded mass spectral data with those of published papers. The use of the same mobile phase composition in both techniques revealed that the miniaturized method exhibited shorter analysis time and higher sensitivity than narrow-bore chromatography. Good intra-day and day-to-day precision of retention time was obtained in both methods with values of RSD less than 3.4 and 0.8% for nano-LC and HPLC, respectively. Quantitative analysis was performed by external standard curve calibration of cyanidin-3-O-glucoside standard. Calibration curves were linear in the concentration ranges studied, 0.1-50 and 6-50 μg/mL for HPLC-UV/Vis and nano-LC-MS, respectively. LOD and LOQ values were good for both methods. In addition to commercial blueberry juice, qualitative and quantitative analysis of other juices (e.g. raspberry, sweet cherry and pomegranate) was performed. The optimized nano-LC-MS method allowed an easy and selective identification and quantification of anthocyanins in commercial fruit juices; it offered good results, shorter analysis time and reduced mobile phase volume with respect to narrow-bore HPLC.

Mitogen-Activated Protein Kinases and Reactive Oxygen Species: How Can ROS Activate MAPK Pathways?

Mitogen-activated protein kinases (MAPKs) are serine-threonine protein kinases that play the major role in signal transduction from the cell surface to the nucleus. MAPKs, which consist of growth factor-regulated extracellular signal-related kinases (ERKs), and the stress-activated MAPKs, c-jun NH₂-terminal kinases (JNKs) and p38 MAPKs, are part of a three-kinase signaling module composed of the MAPK, an MAPK kinase (MAP2K) and an MAPK kinase (MAP3K). MAP3Ks phosphorylate MAP2Ks, which in turn activate MAPKs. MAPK phosphatases (MKPs), which recognize the TXY amino acid motif present in MAPKs, dephosphorylate and deactivate MAPKs. MAPK pathways are known to be influenced not only by receptor ligand interactions, but also by different stressors placed on the cell. One type of stress that induces potential activation of MAPK pathways is the oxidative stress caused by reactive oxygen species (ROS). Generally, increased ROS production in a cell leads to the activation of ERKs, JNKs, or p38 MAPKs, but the mechanisms by which ROS can activate these kinases are unclear. Oxidative modifications of MAPK signaling proteins and inactivation and/or degradation of MKPs may provide the plausible mechanisms for activation of MAPK pathways by ROS, which will be reviewed in this paper.

Anthocyanin-rich black currant extract suppresses the growth of human hepatocellular carcinoma cells

Dietary antioxidants, such as anthocyanins, are helpful in the prevention and control of various diseases by counteracting the imbalance of oxidative and antioxidative factors in the living systems. Black currant (Ribes nigrum L., Grossulariaceae) is known to contain high amounts of anthocyanins (250 mg/100 g fresh fruit). Black currant fruits have been used in Asian and European traditional medicine for the treatment of a variety of diseases. Black currant extract has recently been found to be the second most effective amongst nine different berry extracts studied for their free radical scavenging activity. Constituents present in black currant juice have been found to exert a number of health-promoting effects, including immunomodulatory, antimicrobial and antiinflammatory actions, inhibition of low-density lipoprotein, and reduction of cardiovascular diseases. Although antioxidant and antiinflammatory effects of black currant juice could be of value in preventing and treating oxidative stress- and inflammation-driven cancers, no experimental evidence is available to now. The objective of the present study was to evaluate the potential antiproliferative effects of black currant fruit skin extract against HepG2 human liver cancer cells. The aqueous extract yielded an anthocyanin-rich fraction with cyanidin-3-O-rutinoside as one of the major anthocyanins. This fraction exhibited a potent cytotoxic effect on HepG2 cells and this effect was more pronounced than that of delphinidin and cyanidin, two major aglycones of anthocyanins present in black currant. Our results indicate, for the first time, that black currant skin containing an anthocyanin-rich fraction inhibits the proliferation of liver cancer cells, possibly due to additive as well as synergistic effects. This product could be useful in the prevention and treatment of human hepatocellular carcinoma.

Dietary flavonoids as cancer prevention agents

Dietary agents identified from fruits and vegetables contribute to keeping balanced cell proliferation and preventing cell carcinogenesis. Dietary flavonoids, combined with other components such as various vitamins, play an important role in cancer prevention. Flavonoids act on reactive oxygen species, cell signal transduction pathways related to cellular proliferation, apoptosis, and angiogenesis. Many studies demonstrate that flavonoids are responsible for chemoprevention, although mechanisms of action remain to be investigated. Overall, exciting data show that dietary flavonoids could be considered as a useful cancer preventive approach. This review summarizes recent advancements on potential cancer preventive effects and mechanic insight of dietary flavonoids.

Modulation of genetic and epigenetic biomarkers of colorectal cancer in humans by black raspberries: a phase I pilot study

PURPOSE

This study evaluated the effects of black raspberries (BRBs) on biomarkers of tumor development in the human colon and rectum including methylation of relevant tumor suppressor genes, cell proliferation, apoptosis, angiogenesis, and expression of Wnt pathway genes.

EXPERIMENTAL DESIGN

Biopsies of adjacent normal tissues and colorectal adenocarcinomas were taken from 20 patients before and after oral consumption of BRB powder (60 g/d) for 1-9 weeks. Methylation status of promoter regions of five tumor suppressor genes was quantified. Protein expression of DNA methyltransferase 1 (DNMT1) and genes associated with cell proliferation, apoptosis, angiogenesis, and Wnt signaling were measured.

RESULTS

The methylation of three Wnt inhibitors, SFRP2, SFRP5, and WIF1, upstream genes in Wnt pathway, and PAX6a, a developmental regulator, was modulated in a protective direction by BRBs in normal tissues and in colorectal tumors only in patients who received BRB treatment for an average of 4 weeks, but not in all 20 patients with 1-9 weeks of BRB treatment. This was associated with decreased expression of DNMT1. BRBs modulated expression of genes associated with Wnt pathway, proliferation, apoptosis, and angiogenesis in a protective direction.

CONCLUSIONS

These data provide evidence of the ability of BRBs to demethylate tumor suppressor genes and to modulate other biomarkers of tumor development in the human colon and rectum. While demethylation of genes did not occur in colorectal tissues from all treated patients, the positive results with the secondary endpoints suggest that additional studies of BRBs for the prevention of colorectal cancer in humans now appear warranted.

Black raspberries inhibit intestinal tumorigenesis in apc1638+/- and Muc2-/- mouse models of colorectal cancer

Freeze-dried black raspberries (BRB) produce chemopreventive effects in a rat model of colon carcinogenesis; however, the mechanisms of inhibition were not determined. Herein, we used two mouse models of human colorectal cancer to determine if dietary BRBs would inhibit colorectal tumor development and to investigate the underlying mechanisms. We found that a 12-week feeding of BRBs significantly inhibited intestinal tumor formation in both models; reducing tumor incidence by 45% and tumor multiplicity by 60% in Apc1638+/- mice and tumor incidence and multiplicity by 50% in Muc2-/- mice. Mechanistic studies revealed that BRBs inhibit tumor development in Apc1638+/- mice by suppressing β-catenin signaling and in Muc2-/- mice by reducing chronic inflammation. Intestinal cell proliferation was inhibited by BRBs in both animal models; however, the extent of mucus cell differentiation was not changed in either model. Collectively, our data suggest that BRBs are highly effective in preventing intestinal tumor development in both Apc1638+/- and Muc2-/- mice through targeting multiple signaling pathways.

Inhibition of pro-inflammatory responses and antioxidant capacity of Mexican blackberry (Rubus spp.) extracts

Total polyphenolic and anthocyanin- and proanthocyanidin-rich fractions from wild blackberry genotypes (WB-3, WB-7, WB-10, and WB-11), a domesticated noncommercial breeding line (UM-601), and a commercial cultivar (Tupy) were evaluated for inhibition of pro-inflammatory responses [nitric oxide (NO) production, inducible nitric oxide synthase (iNOS) expression, cyclooxygenase-2 (COX-2) expression, and prostaglandin E2 (PGE2)] in RAW 264.7 macrophages stimulated by lipopolysaccharide (LPS). At 50 microM [cyanidin-3-O-glucoside (C3G) or catechin equivalent], most fractions significantly (P<0.05) inhibited all markers. The anthocyanin-rich fraction from WB-10 and the proanthocyanidin-rich fraction from UM-601 exhibited the highest NO inhibitory activities (IC50=16.1 and 15.1 microM, respectively). Proanthocyanidin-rich fractions from the wild WB-10 showed the highest inhibition of iNOS expression (IC50=8.3 microM). Polyphenolic-rich fractions from WB-7 and UM-601 were potent inhibitors of COX-2 expression (IC50=19.1 and 19.3 microM C3G equivalent, respectively). For most of the extracts, antioxidant capacity was significantly correlated with NO inhibition. Wild genotypes of Mexican blackberries, as rich sources of polyphenolics that have both antioxidant and anti-inflammatory properties, showed particular promise for inclusion in plant improvement programs designed to develop new varieties with nutraceutical potential.

Effects of a flavonol-rich diet on select cardiovascular parameters in a Golden Syrian hamster model

The concept that the consumption of a diet rich in flavonoids can be associated with a reduced risk for cardiovascular disease is becoming increasingly accepted. In the present study we investigated the effects of the following four diets on blood pressure and cholesterol ester levels in hypercholesterolemic Golden Syrian hamsters: a high-fat, high-cholesterol diet (HFHC); a HFHC with 2% cranberry concentrate powder (HFHC+CE); a HFHC with 0.1% rutin (HFHC+Rutin); and a HFHC with 30 mg/kg vitamin E (HFHC+Vit.E). Diets were fed for either 12 or 20 weeks. Over the experimental period, heart rate and blood pressure measurements increased in the animals fed HFHC and HFHC+Vit.E; in contrast, these measurements were not increased in the animals fed HFHC+CE and HFHC+Rutin. Mesenteric and total abdominal fat were significantly lower in the animals fed HFHC+Rutin than in animals fed the other three diets. Ratios of plasma high-density lipoprotein cholesterol (HDL-C) to very-low-density lipoprotein cholesterol and of plasma HDL-C to low-density lipoprotein cholesterol were significantly higher in animals consuming HFHC+Vit.E than in animals fed the other three diets. Aortic cholesteryl ester levels were significantly lower in animals fed HFHC+CE, HFHC+Rutin, and HFHC+Vit.E at 20 weeks than in the animals fed HFHC. Fasting blood glucose concentrations were significantly lower in animals fed HFHC+Rutin and HFHC+Vit.E, and glucose clearance rates improved in animals fed HFHC+Rutin compared to animals fed the other three diets. Results obtained from this study support the concept that the chronic consumption of a flavonoid-rich diet can be beneficial with respect to cardiovascular health.