Mechanisms of combined action of different chemopreventive dietary compounds

Effect of caffeic acid derivatives on polychlorinated biphenyls induced hepatotoxicity in male mice

Chronic exposure to coplanar polychlorinated biphenyls (PCBs), a potent inducer of toxic reactive oxygen species (ROS), in the environment and food can cause liver diseases. It remains unknown whether caffeic acid derivatives (CADs) exerted protective effect on PCB-induced hepatotoxicity. We sought to evaluate the activities of 3 CADs on PCB169-induced oxidative stress and DNA damage in the liver. Male ICR mice were administered with 1 μmol/mL PCB169 at 5 mL/kg body weight for 2 weeks. The mice were given CADs by gastric gavage for 3 weeks. We found that PCB169 decreased the growth rate and reduced the levels of superoxide dismutase (SOD), glutathione (GSH) and GSH peroxidase (GPx). It increased the liver weight, malondialdehyde (MDA) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels and CYP1A1 activity in the liver tissues and plasma of mice (P<0.05). Pretreatment of mice with CADs restored the above parameters to normal levels. There was a synergistic protective effect between CADs in preventing MDA and 8-OHdG formation and inducing CYP1A1 and phase II metabolism enzyme (SOD, GPx) activities (P<0.05). In conclusion, PCB169 induced hepatotoxicity and pretreatment with CADs had synergistic protective effects on liver damage.

Synergistic action of compounds isolated from the hexane extract of Ardisia crispa root against tumour-promoting effect, in vitro

An isomeric mixture of α,β-amyrin (triterpene) and 2-methoxy-6-undecyl-1,4-benzoquinone (quinone) isolated from the Ardisia crispa root hexane (ACRH) extract was reported to possess anti-inflammatory properties in vivo. Considering the close association between inflammation and cancer, on top of the lack of antitumour study on those compounds, this study aimed to determine the potential of both compounds against tumour promotion in vitro, either as single agent or in combination. Triterpene and quinone compounds, as well as triterpene-quinone fraction (TQF) and ACRH were subjected to inhibition of Epstein-Barr virus-early antigen (EBV-EA) activation assay for that purpose. Compared with curcumin (positive control), inhibition against EBV-EA activation occurred in the order: ACRH>TQF ≥ curcumin>α,β-amyrin ≥ 2-methoxy-6-undecyl-1,4-benzoquinone. These findings reported, for the first time, the antitumor-promoting effect of α,β-amyrin and 2-methoxy-6-undecyl-1,4-benzoquinone from the roots of A. crispa, which was enhanced when both compounds act in synergy.

Bifunctional chemopreventive effects of Adenocaulon himalaicum through induction of detoxification enzymes and apoptosis

Phase II detoxification enzymes are known to play essential roles in the detoxification and elimination of activated carcinogens during tumor initiation, while apoptosis is one of the most important chemopreventive targets for inhibiting tumor promotion in cancer. In this study, we investigated the cancer chemopreventive activity of two plant extracts, the ethanolic extract of Adenocaulon himalaicum (AHE) and the butanolic fraction of AHE (AHB). Both, the AHE and AHB induced NQO1 activity and had relatively high chemoprevention indices (CI=12.4). The AHE and AHB were associated with increased NQO1 and HO-1 mRNA levels via Nrf2-ARE pathway activation. In addition, the AHB increased CYP1A1 activity through AhR-XRE pathway activation. We also found that the AHE and AHB induced apoptosis, as evidenced by phosphatidylserine externalization, an increase in the sub-G0/G1 content, chromatin condensation, poly(ADP-ribose) polymerase cleavage, and p53 induction. These data suggest that AHE and AHB act as bifunctional inducers and that their chemopreventive effects result from the biphasic induction of phase II detoxification enzymes and apoptosis. Therefore, these results suggest that A. himalaicum plant extracts have potential for use as chemopreventive agents for the prevention and/or treatment of human cancers.

Zyflamend, a polyherbal mixture, down regulates class I and class II histone deacetylases and increases p21 levels in castrate-resistant prostate cancer cells

BACKGROUND

Zyflamend, a mixture containing extracts of ten herbs, has shown promise in a variety of preclinical cancer models, including prostate cancer. The current experiments were designed to investigate the effects of Zyflamend on the expression of class I and II histone deacetylases, a family of enzymes known to be over expressed in a variety of cancers.

METHODS

CWR22Rv1 cells, a castrate-resistant prostate cancer cell line, were treated with Zyflamend and the expression of class I and II histone deacetylases, along with their downstream target the tumor suppressor gene p21, was investigated. Involvement of p21 was confirmed with siRNA knockdown and over expression experiments.

RESULTS

Zyflamend down-regulated the expression of all class I and II histone deacetylases where Chinese goldthread and baikal skullcap (two of its components) appear to be primarily responsible for these results. In addition, Zyflamend up regulated the histone acetyl transferase complex CBP/p300, potentially contributing to the increase in histone 3 acetylation. Expression of the tumor suppressor gene p21, a known downstream target of histone deacetylases and CBP/p300, was increased by Zyflamend treatment and the effect on p21 was, in part, mediated through Erk1/2. Knockdown of p21 with siRNA technology attenuated Zyflamend-induced growth inhibition. Over expression of p21 inhibited cell growth and concomitant treatment with Zyflamend enhanced this effect.

CONCLUSIONS

Our results suggest that the extracts of this polyherbal combination increase histone 3 acetylation, inhibit the expression of class I and class II histone deacetylases, increase the activation of CBP/p300 and inhibit cell proliferation, in part, by up regulating p21 expression.

Ocimum sanctum Linn. (Tulsi): an ethnomedicinal plant for the prevention and treatment of cancer

Ocimum sanctum Linn., commonly known as 'Tulsi' or 'Holy Basil', is considered to be the most sacred herb of India. Several anatomical parts of O. sanctum are known to have an impressive number of therapeutic properties and accordingly find use in several traditional systems of medicine, such as Ayurveda, Unani, and Siddha. Scientific investigations have shown that O. sanctum has a plethora of biological and pharmacological activities. The presence of an impressive number of phytoconstituents in O. sanctum could explain its exceptional beneficial effects. Although several recent articles provide an overview of the various pharmacological properties of O. sanctum, the use of this herb for either prevention or therapy of oncologic diseases has not been exclusively and critically discussed in the literature. The present review critically and comprehensively examines the current knowledge on the chemopreventive and therapeutic potential of O. sanctum. The review also examines, in detail, the biochemical and molecular mechanisms involved in the antineoplastic effects of O. sanctum. Finally, we discuss the role of synergy, current limitations, and future directions of research toward the effective use of this ethnomedicinal plant for the prevention and treatment of human cancer.

Shrimp lipids: a source of cancer chemopreventive compounds

Shrimp is one of the most popular seafoods worldwide, and its lipids have been studied for biological activity in both, muscle and exoskeleton. Free fatty acids, triglycerides, carotenoids, and other lipids integrate this fraction, and some of these compounds have been reported with cancer chemopreventive activities. Carotenoids and polyunsaturated fatty acids have been extensively studied for chemopreventive properties, in both in vivo and in vitro studies. Their mechanisms of action depend on the lipid chemical structure and include antioxidant, anti-proliferative, anti-mutagenic, and anti-inflammatory activities, among others. The purpose of this review is to lay groundwork for future research about the properties of the lipid fraction of shrimp.

Procyanidins from evening primrose (Oenothera paradoxa) defatted seeds inhibit invasiveness of breast cancer cells and modulate the expression of selected genes involved in angiogenesis, metastasis, and apoptosis

There is a growing interest in plant polyphenols (including flavanols) that exhibit pleiotropic biological activities such as antiinflammatory, antioxidant, and anticancer effects. Here, we report for the first time the inhibition of MDA-MB-231 breast cancer cell viability and invasiveness by an evening primrose flavanol preparation (EPFP). We observed a decrease in MDA-MB-231 viability of 50% vs. a control after 72 h of incubation with EPFP at a concentration of 58 μM gallic acid equivalents (GAE) and an inhibition of their invasiveness of 65% vs. a control at 75 μM GAE after 48 h of incubation. EPFP caused a 10-fold reduction in matrix metalloproteinase-9 (MMP-9) activity at 100 μM GAE. Furthermore, through modulation of mRNA expression, EPFP reduced the expression levels of the following proteins: antiapoptotic Bcl-2, angiogenic vascular endothelial growth factor (VEGF), and 2 transcription factors (c-Jun, c-Fos). Moreover, analysis by flow cytometry revealed that EPFP induced apoptosis in MDA-MB-231 cells. In conclusion, our data shows that EPFP inhibits cell viability by increasing apoptosis and decreases cell invasiveness by decreasing angiogenesis.

Luteolin supplementation modulates mammary tumor growth in C3H mice fed diet with high- and low-fat content

In this study we investigated the effects of luteolin supplementation (0.05% w/w) on mammary tumor growth in C3H mice, a strain of mouse mammary tumor virus negative, fed either high-fat (45% fat of energy) or low-fat diet (15% fat of energy). Animals (n = 12/group) were allocated into 4 experimental groups (low-fat diet, low-fat diet + luteolin supplementation, high-fat diet, high-fat diet + luteolin supplementation). Experimental diet were fed for 13 wk and 7,12-dimethylbenz[a]anthracene was administered once a week for 6 wk starting at Week 1 to induce mammary tumors. Study results showed that animals on low-fat diet supplemented with luteolin exhibited longer tumor latency and lower tumor weights and sizes compared to the other groups. Animals fed high-fat diet showed increased serum IGF-1 levels and the elevated mammary tissue expression of Ki-67, IRS-1, pp38, Cdk4, and Cdk6. Luteolin inhibited IRS-1, Cdk4, and Cdk6 expression in high-fat fed animals. The expression of pp38, cyclinD1, and Bcl-xL was suppressed by luteolin supplementation both in the low-fat and high-fat diet groups. These results suggest that excess energy supply increases the risk of mammary tumor formation and luteolin suppresses tumor formation regardless of dietary fat content through its cell cycle regulatory and proapoptotic activity.

Potent anti-cancer effects of citrus peel flavonoids in human prostate xenograft tumors

Prostate cancer is one of the most prevalent malignancies and is the second leading cause of cancer-related deaths in men. Fruit and vegetable consumption is a novel, non-toxic therapeutic approach that can be used to prevent and treat prostate cancer. Citrus peels and their extracts have been reported to have potent pharmacological activities and health benefits due to the abundance of flavonoids in citrus fruits, particularly in the peels. Our previous studies demonstrated that oral administration of Gold Lotion (GL), an extract of multiple varieties of citrus peels containing abundant flavonoids, including a large percentage of polymethoxyflavones (PMFs), effectively suppressed azoxymethane (AOM)-induced colonic tumorigenesis. However, the efficacy of GL against prostate cancer has not yet been investigated. Here, we explored the anti-tumor effects of GL using a human prostate tumor xenograft mouse model. Our data demonstrated that treatment with GL by both intraperitoneal (i.p.) injection and oral administration dramatically reduced both the weights (57%-100% inhibition) and volumes (78%-94% inhibition) of the tumors without any observed toxicity. These inhibitory effects were accompanied by mechanistic down-regulation of the protein levels of inflammatory enzymes (inducible nitric oxide synthase, iNOS and cyclooxygenase-2, COX-2), metastasis (matrix metallopeptidase-2, MMP-2 and MMP-9), angiogenesis (vascular endothelial growth factor, VEGF), and proliferative molecules, as well as by the induction of apoptosis in prostate tumors. Our findings suggest that GL is an effective anti-cancer agent that may potentially serve as a novel therapeutic option for prostate cancer treatment.

Regulation of cell cycle transition and induction of apoptosis in HL-60 leukemia cells by the combination of Coriolus versicolor and Ganoderma lucidum

Medicinal mushrooms have served as the mainstay of treatment for a variety of human illnesses in Asian countries, mostly as supplements by cancer patients. Extracts prepared from Trametes versicolor under the trade name of I'm-Yunity exhibit anti-tumorigenic activities, as supported by inhibition of the proliferation and induction of apoptosis in malignant cells. Similar effects have also been observed for the Reishi mushroom Ganoderma lucidum. The two mushrooms exert their medicinal activities primarily through a family of polysaccharo-peptides. Despite the common identity in their bioactive ingredients, whether their combination might elicit an expanded efficacy and mechanism has not been investigated. In the present study, we investigated similarities and differences between extracts prepared from I'm-Yunity and from a formulation denoted I'm-Yunity-Too combining I'm-Yunity and Ganoderma lucidum. By assaying their anti-proliferative and anti-apoptotic effects using human promyelocytic HL-60 cells, we found that the ethanolic extract of I'm-Yunity-Too was more active in inducing cell death compared to I'm-Yunity, based on measured changes in the expression of caspase 3 and Bax. Moreover, ethanolic extracts of I'm-Yunity-Too exhibited more potent activity compared to its aqueous extracts with regard to suppression of the growth and induction of apoptosis, as assayed by the more pronounced downregulation of phosphorylation of Rb and increased cleavage of poly(ADP‑ribose) polymerase (PARP) from its native 112-kDa form to the inactive 89-kDa product. These results suggested that the chemopreventive potential of I'm-Yunity may be enhanced by adding Ganoderma lucidum and that their bioactive ingre-dients potentially exhibit mechanistic synergism suggesting a more efficacious adjunct in chemotherapy.

Flavanols from evening primrose (Oenothera paradoxa) defatted seeds inhibit prostate cells invasiveness and cause changes in Bcl-2/Bax mRNA ratio

In this study, we assessed the influence of an evening primrose flavanol preparation (EPFP) on proliferation and invasiveness of human prostate cancer cells (DU 145) and immortalized prostate epithelial cells (PNT1A). We report for the first time that EPFP reduces DU 145 cell proliferation (IC50 = 97 μM GAE for 72 h incubation) and invasiveness (by 24% versus control at 75 μM GAE). EPFP strongly inhibited PNT1A invasiveness in a concentration-dependent manner (by 67% versus control at 75 μM GAE) and did not cause a reduction in their proliferation. Furthermore, EPFP inhibited the activities of MMP-2 and MMP-9 secreted to culture medium by PNT1A cells by 84% and 34% versus control at 100 μM GAE, respectively. In the case of DU 145, MMP-9 activity at 100 μM GAE was reduced by 37% versus control. Moreover, the evening primrose seed flavanols suppressed the expression of selected genes (MMP-1, MMP-9, MMP-14, c-Fos, c-Jun, and VEGF) and also caused favorable changes in Bcl-2/Bax mRNA ratio which render DU 145 cells more sensitive to apoptosis-triggering agents. An additional confirmation of the proapoptotic activity of EPFP toward DU 145 was visualization of characteristic apoptotic bodies by DAPI staining. In conclusion, this study suggests that EPFP may increase apoptosis and reduce angiogenesis of prostate cancer cells.

Micronutrient intake and risk of prostate cancer in a cohort of middle-aged, Danish men

PURPOSE

Micronutrients may protect against prostate cancer. However, few studies have had high-quality assessment of both dietary and supplemental consumption of micronutrients, rendering possible different source-specific effects difficult to discern. This study evaluates associations between intake of vitamin C, E, folate, and beta-carotene and prostate cancer risk, focusing on possible different effects of dietary, supplemental, or total intake and on potential effect modification by alcohol intake and BMI.

METHODS

Danish prospective cohort study of 26,856 men aged 50-64 years with questionnaire-based information on diet, supplements, and lifestyle. Hazard ratios (HRs) for prostate cancer associated with micronutrient intake were calculated using Cox proportional hazard analyses.

RESULTS

During follow-up (1993-2010), 1,571 prostate cancer cases were identified. Supplemental folic acid was inversely associated with prostate cancer risk, notably on a continuous scale [HR 0.88 (95 % CI 0.79-0.98) per 100 μg increase/day]. The risk reduction was largely confined to non-aggressive tumors [HR 0.71 (0.55-0.93) per 100 μg increase/day]. No influence on prostate cancer risk was observed for dietary folate or for the other studied micronutrients, regardless of source. We found no significant effect modification by alcohol intake and BMI in relation to any micronutrient.

CONCLUSION

Our study may indicate an inverse association between folic acid and prostate cancer; however, the inverse association was confined to supplemental folic acid and non-aggressive prostate cancer and may thus be a chance finding. Further studies are warranted to evaluate our findings.

Use of the Combination Index to determine interactions between plant-derived phenolic acids on hepatotoxicity endpoints in human and rat hepatoma cells

The beneficial or adverse effects of isolated phytochemicals are not always concordant with effects of the botanical dietary supplements from which they were derived. This disparity could be due to interactions between the various phytochemicals present in the whole plant. The phenolic acids, rosmarinic acid (RA), caffeic acid (CA) and ferulic acid (FA) are widely present in foods and dietary supplements, and they are assumed to exert various beneficial biological effects. However, there is little data on the potential biological interactions of these three phenolic acids which commonly occur together and are linked metabolically. In the present study, liver toxicity of the three phenolic acids was assessed on the three compounds singly and in various binary and one ternary combinations. A series of in vitro endpoints relevant to liver toxicity were evaluated in both a human (HepG2/C3A) and rat (MH1C1) hepatocyte cell line. The Combination Index (CI) was calculated for each endpoint from both the concentration responses of the single compounds and the responses of the various binary and ternary mixtures. Both synergistic and antagonistic interactions were observed for some endpoints and some combinations of test agents. Interactions were most prevalent in measures of oxidative stress and cytochrome P450 activities in both cell types. There was only a 53% concordance between the rat and human cells which may be suggestive of species differences. The data suggest an approach for better characterizing the beneficial or adverse effects of complex botanical products through evaluation of interactions between individual phytochemical components.

Effects of dietary carbohydrate replaced with wild rice (Zizania latifolia (Griseb) Turcz) on insulin resistance in rats fed with a high-fat/cholesterol diet

Wild rice (WR) is a very nutritious grain that has been used to treat diabetes in Chinese medicinal practice. City diet (CD) is based on the diet consumed by Asian area residents in modern society, which is rich in saturated fats, cholesterol and carbohydrates. The present study was aimed at evaluating the effects of replacing white rice and processed wheat starch of CD with WR as the chief source of dietary carbohydrates on insulin resistance in rats fed with a high-fat/cholesterol diet. Except the rats of the low-fat (LF) diet group, the rats of the other three groups, including to high-fat/cholesterol (HFC) diet, CD and WR diet, were fed with high-fat/cholesterol diets for eight weeks. The rats fed with CD exhibited higher weight gain and lower insulin sensitivity compared to the rats consuming a HFC diet. However, WR suppressed high-fat/cholesterol diet-induced insulin resistance. WR decreased liver homogenate triglyceride and free fatty acids levels, raised serum adiponectin concentration and reduced serum lipocalin-2 and visfatin concentrations. In addition, the WR diet potently augmented the relative expressions of adiponectin receptor 2, peroxisome proliferator-activated receptors, alpha and gamma, and abated relative expressions of leptin and lipocalin-2 in the tissues of interest. These findings indicate that WR is effective in ameliorating abnormal glucose metabolism and insulin resistance in rats, even when the diet consumed is high in fat and cholesterol.

Quercetin enhances the antitumor activity of trichostatin A through upregulation of p53 protein expression in vitro and in vivo

This study investigated the effects of quercetin on the anti-tumor effect of trichostatin A (TSA), a novel anticancer drug, in vitro and in vivo and the possible mechanisms of these effects in human lung cancer cells. We first showed that quercetin (5 µM) significantly increased the growth arrest and apoptosis in A549 cells (expressing wild-type p53) induced by 25 ng/mL of (82.5 nM) TSA at 48 h by about 25% and 101%, respectively. However, such enhancing effects of quercetin (5 µM) were not significant in TSA-exposed H1299 cells (a p53 null mutant) or were much lower than in A549 cells. In addition, quercetin significantly increased TSA-induced p53 expression in A549 cells. Transfection of p53 siRNA into A549 cells significantly but not completely diminished the enhancing effects of quercetin on TSA-induced apoptosis. Furthermore, we demonstrated that quercetin enhanced TSA-induced apoptosis through the mitochondrial pathway. Transfection of p53 siRNA abolished such enhancing effects of quercetin. However, quercetin increased the acetylation of histones H3 and H4 induced by TSA in A549 cells, even with p53 siRNA transfection as well as in H1299 cells. In a xenograft mouse model of lung cancer, quercetin enhanced the antitumor effect of TSA. Tumors from mice treated with TSA in combination with quercetin had higher p53 and apoptosis levels than did those from control and TSA-treated mice. These data indicate that regulation of the expression of p53 by quercetin plays an important role in enhancing TSA-induced apoptosis in A549 cells. However, p53-independent mechanisms may also contribute to the enhancing effect of quercetin.

Plants, diet, and health

Chronic disease is a major social challenge of the twenty-first century. In this review, we examine the evidence for discordance between modern diets and those on which humankind evolved as the cause of the increasing incidence of chronic diseases, and the evidence supporting consumption of plant foods as a way to reduce the risk of chronic disease. We also examine the evidence for avoiding certain components of plant-based foods that are enriched in Western diets, and review the mechanisms by which different phytonutrients are thought to reduce the risk of chronic disease. This body of evidence strongly suggests that consuming more fruits and vegetables could contribute both to medical nutrition therapies, as part of a package of treatments for conditions like type 2 diabetes, heart disease, cancer, and obesity, and to the prevention of these diseases. Plant science should be directed toward improving the quality of plant-based foods by building on our improved understanding of the complex relationships between plants, our diet, and our health.

Carotenoids and total phenolic contents in plant foods commonly consumed in Korea

Phytochemicals are reported to provide various biological functions leading to the promotion of health as well as the reduced risk of chronic diseases. Fat-soluble plant pigments, carotenoids, are extensively studied micronutrient phytochemicals for their potential health benefits. It is noteworthy that specific carotenoids may be responsible for different protective effects against certain diseases. In addition, each carotenoid can be obtained from different types of plant foods. Considering the fact that the phytochemical content in foods can vary according to, but not limited to, the varieties and culture conditions, it is important to establish a database of phytochemicals in locally produced plant foods. Currently, information on individual carotenoid content in plant foods commonly consumed in Korea is lacking. As the first step to support the production and consumption of sustainable local plant foods, carotenoids and total phenolic contents of plant foods commonly consumed in Korea are presented and their potential biological functions are discussed in this review.

Obesity-related colon cancer: dietary factors and their mechanisms of anticancer action

Overweight/obesity is an epidemic in the US as well as in other developed countries, affecting two-thirds of Americans and an estimated 2.3 billion people worldwide. Obesity increases the risk for Type 2 diabetes, cardiovascular disease and cancer. For example, epidemiological studies have established a strong association between obesity and colon cancer. It is generally accepted that metabolic changes associated with overweight/obesity, particularly abdominal obesity and changes in adipocyte function, contribute to the increased risk of colon cancer. Understanding the mechanisms underlying this association is important for the development of preventive strategies for colon cancer. Part of these preventive strategies may be based on dietary factors, such as vitamins, minerals (e.g. selenium), fibre, phytochemicals and phenolic compounds. These anticancer nutrients may counteract the molecular changes associated with obesity. The present article reviews the evidence that inflammation and insulin resistance induced by obesity are the molecular mediators of the association between obesity and colon cancer. We also evaluate the evidence for the ability of dietary factors to target the obesity-induced changes and, thus, protect against colon cancer.

Effects of selected phytoestrogens and their mixtures on the function of the thyroid hormone and the aryl hydrocarbon receptor

Phytoestrogens (PEs) are natural plant components, which can induce biologic responses in vertebrates by mimicking or blocking the actions of natural hormones or influencing the hormone production in the body. This study investigated the effect of different mixtures composed of food-relevant PEs on the thyroid hormone (TH) system assessing the proliferation of the 3,3',5-triiodi-L-thryonine (T3) dependent rat pituitary GH3 cells using the T-screen assay, and the effect on the aryl hydrocarbon receptor (AhR) transactivation using an AhR-luciferase reporter gene assay. Most tested PEs and their mixtures showed effect on both the TH and AhR system. Single isoflavonoid metabolites and their mixture and coumestrol induced GH3 cell growth and AhR transactivity dose-dependently. Isoflavonoid metabolites elicited an additive effect on the T3-dependent GH3 cell growth, and a synergistic effect on the AhR transactivity. In conclusion, nutrition-relevant PEs, alone and in mixture may possess endocrine-disrupting potential by interfering with TH and AhR functions, which need to be considered when assessing the effects on human health.

Antiproliferative and immunoactivatory ability of an enzymatic extract from rice bran

The validation of natural products as source of functional foods or nutraceuticals has become an important issue in current health research. Thus, the present work has tested on MOLT-4 cells (human T cell acute lymphoblastic leukemic) the antiproliferative effect of a water-soluble enzymatic extract from rice bran (EERB). Present work shows that EERB induces cellular death in MOLT-4 cells in a dose-dependent way (0-10mg/mL) but not in non-tumoral lymphocytes. Flow cytometric analysis of MOLT-4 cells treated with EERB showed the presence of death cells by apoptosis rather than necrosis. Additionally, EERB also exerts an immunoactivatory effect on N13 microglia cells, by inducing TNF-alpha (tumour necrosis factor-α) expression, which plays a key role in the innate immune response to infection. Accordingly, we can propose EERB as a useful natural standardized extract with antiproliferative and immunoactivatory ability that would be beneficial to apply in the functional food field.

Resveratrol biosynthesis: plant metabolic engineering for nutritional improvement of food

The plant polyphenol trans-resveratrol (3, 5, 4'-trihydroxystilbene) mainly found in grape, peanut and other few plants, displays a wide range of biological effects. Numerous in vitro studies have described various biological effects of resveratrol. In order to provide more information regarding absorption, metabolism, and bioavailability of resveratrol, various research approaches have been performed, including in vitro, ex vivo, and in vivo models. In recent years, the induction of resveratrol synthesis in plants which normally do not accumulate such polyphenol, has been successfully achieved by molecular engineering. In this context, the ectopic production of resveratrol has been reported to have positive effects both on plant resistance to biotic stress and the enhancement of the nutritional value of several widely consumed fruits and vegetables. The metabolic engineering of plants offers the opportunity to change the content of specific phytonutrients in plant - derived foods. This review focuses on the latest findings regarding on resveratrol bioproduction and its effects on the prevention of the major pathological conditions in man.

The naringenin-induced proapoptotic effect in breast cancer cell lines holds out against a high bisphenol a background

Fruit and vegetable consumption has generally been associated with the prevention or suppression of cancer. However, food could contain a multitude of chemicals (e.g., bisphenol A; BPA) that could synergize or antagonize the effects of diet-derived compounds. Remarkably, food containers (e.g., water and infant bottles) are the largest source of exposure to BPA for human beings. Here, the effects of the coexposure of naringenin (Nar, 1.0 × 10(-9) M to 1.0 × 10(-4) M) and BPA (1.0 × 10(-5) M) in estrogen-dependent breast cancer cell lines expressing (i.e., MCF-7 and T47D) or not expressing (i.e., MDA-MB-231) estrogen receptor α (ERα) are reported. Although both Nar and BPA bind to ERα, they induce opposite effects on breast cancer cell growth. BPA induces cell proliferation, whereas Nar only decreases the number of ERα-positive cells (i.e., MCF-7 and T47D). Notably, even in the presence of BPA, Nar impairs breast cancer cell proliferation by activating caspase-3. The molecular pathways involved require p38 activation, whereas, the BPA-induced AKT activation is completely prevented by the Nar treatment. As a whole, Nar maintains its proapoptotic effects even in the presence of the food contaminant BPA, thus, enlarging the chemopreventive potential of this flavanone.

Association between habitual dietary flavonoid and lignan intake and colorectal cancer in a Spanish case-control study (the Bellvitge Colorectal Cancer Study)

BACKGROUND

Flavonoid-rich foods, such as fruits, vegetables, and tea, may have a protective effect upon colorectal cancer. However, current epidemiological evidence for a protective effect of flavonoid intake upon colorectal cancer is promising but not conclusive.

OBJECTIVE

To examine the relation between dietary flavonoid and lignan intakes and the risk of colorectal cancer within a Spanish population.

DESIGN

Data from the Bellvitge Colorectal Cancer Study, a case-control study (424 cases with incident colorectal cancer and 401 hospital-based controls), were used. A reproducible and validated food frequency questionnaire was administered in personal interviews. An ad hoc food composition database on flavonoids and lignans was compiled, mainly using data from the US Department of Agriculture and Phenol-Explorer databases. Adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated using unconditional logistic regression models.

RESULTS

An inverse association was found between intake of total flavonoids (OR, 0.59; 95 % CI, 0.35-0.99 for the highest vs. the lowest quartile; p for trend = 0.04), lignans (OR, 0.59; 95 % CI, 0.34-0.99; p for trend = 0.03), and some individual flavonoid subgroups (flavones, proanthocyanidins) and the risk of colorectal cancer. Separate analyses by cancer site showed similar results.

CONCLUSIONS

Intake of total dietary flavonoids (particularly certain flavonoid subgroups) and lignans was inversely associated with colorectal cancer risk in a Spanish population.

Epigenetic diet: impact on the epigenome and cancer

A number of bioactive dietary components are of particular interest in the field of epigenetics. Many of these compounds display anticancer properties and may play a role in cancer prevention. Numerous studies suggest that a number of nutritional compounds have epigenetic targets in cancer cells. Importantly, emerging evidence strongly suggests that consumption of dietary agents can alter normal epigenetic states as well as reverse abnormal gene activation or silencing. Epigenetic modifications induced by bioactive dietary compounds are thought to be beneficial. Substantial evidence is mounting proclaiming that commonly consumed bioactive dietary factors act to modify the epigenome and may be incorporated into an 'epigenetic diet'. Bioactive nutritional components of an epigenetic diet may be incorporated into one's regular dietary regimen and used therapeutically for medicinal or chemopreventive purposes. This article will primarily focus on dietary factors that have been demonstrated to influence the epigenome and that may be used in conjunction with other cancer prevention and chemotherapeutic therapies.

Analysis of in vitro chemoprevention of genotoxic damage by phytochemicals, as single agents or as combinations

Cancer chemoprevention with low-dose combinations of bioactive phytochemicals instead of single agents has been suggested to induce less toxicity and improve efficacy. In this study, we selected four plant food-based phytochemicals, viz. chlorogenic acid (CLA), pelargonidin (PEL), resveratrol (RES) and epigallocatechin gallate (EGCG) to evaluate the in vitro chemoprevention of genotoxic damage in HL-60 cells. These agents were tested either individually or as a combination at two concentrations (with a 10-fold difference) against the genotoxins mitomycin C (MMC), diepoxybutane (DEB) and patulin (PAT). Our preliminary ferric reducing antioxidant power (FRAP) assay demonstrated additive effects when PEL, CLA, RES and EGCG were combined. Results of the cytokinesis-block micronucleus test showed significant protection against genotoxic damage induced by PAT, DEB and MMC when CLA, PEL, RES and EGCG were tested individually. This protective effect of the phytochemicals was not concentration-related. Both low- and high-concentration combinations of CLA, PEL, RES and EGCG showed significant reducing effects on the frequencies of micronuclei induced by PAT, DEB and MMC. However, the micronucleus test did not provide indications of additive or synergistic effects with this combination of phytochemicals. In conclusion, the chemo-preventive effects of PEL, CLA, RES and EGCG against genotoxic damage induced by MMC, DEB and PAT are indicative of a 'saturation effect' when higher concentrations and combinations of these phytochemicals are used.

Identification and analysis of the active phytochemicals from the anti-cancer botanical extract Bezielle

Bezielle is a botanical extract that has selective anti-tumor activity, and has shown a promising efficacy in the early phases of clinical testing. Bezielle inhibits mitochondrial respiration and induces reactive oxygen species (ROS) in mitochondria of tumor cells but not in non-transformed cells. The generation of high ROS in tumor cells leads to heavy DNA damage and hyper-activation of PARP, followed by the inhibition of glycolysis. Bezielle therefore belongs to a group of drugs that target tumor cell mitochondria, but its cytotoxicity involves inhibition of both cellular energy producing pathways. We found that the cytotoxic activity of the Bezielle extract in vitro co-purified with a defined fraction containing multiple flavonoids. We have isolated several of these Bezielle flavonoids, and examined their possible roles in the selective anti-tumor cytotoxicity of Bezielle. Our results support the hypothesis that a major Scutellaria flavonoid, scutellarein, possesses many if not all of the biologically relevant properties of the total extract. Like Bezielle, scutellarein induced increasing levels of ROS of mitochondrial origin, progressive DNA damage, protein oxidation, depletion of reduced glutathione and ATP, and suppression of both OXPHOS and glycolysis. Like Bezielle, scutellarein was selectively cytotoxic towards cancer cells. Carthamidin, a flavonone found in Bezielle, also induced DNA damage and oxidative cell death. Two well known plant flavonoids, apigenin and luteolin, had limited and not selective cytotoxicity that did not depend on their pro-oxidant activities. We also provide evidence that the cytotoxicity of scutellarein was increased when other Bezielle flavonoids, not necessarily highly cytotoxic or selective on their own, were present. This indicates that the activity of total Bezielle extract might depend on a combination of several different compounds present within it.

Combinatorial strategies employing nutraceuticals for cancer development

Cancer is the second leading cause of death worldwide. Therefore, the fight against cancer is one of the most important areas of research in medicine, and one that possibly contributes to the increased interest in chemoprevention as an alternative approach to the control of cancer. Cancer prevention by nutraceuticals present in fruits and vegetables has received considerable attention because of their low cost and wide safety margin. A substantial amount of evidence from human, animal, and cell culture studies has shown cancer chemopreventive effects from these natural products. However, single-agent intervention has failed to produce the expected outcome in clinical trials; therefore, combinations of nutraceuticals are gaining increasing popularity. Thus, combinations of nutraceuticals that mimic real-life situations and are competent in targeting multiple targets with very little or virtually no toxicity are needed. In this review, we summarize the results of those studies that report combinatorial cancer chemopreventive action of various nutraceuticals and their combinations with anticancer drugs.

Procyanidins from Japanese quince (Chaenomeles japonica) fruit induce apoptosis in human colon cancer Caco-2 cells in a degree of polymerization-dependent manner

Plant proanthocyanidins, including procyanidins, display various biological activities. Here we report an inhibition of human colon cancer Caco-2 cell growth by the extract from Japanese quince fruit and the procyanidin-rich fractions of the extract. We observed that the amount of apoptotic Caco-2 cells increased by 52.1% vs. control after 72-h incubation with 50 μg extract/mL, as assessed by flow cytometry and image cytometry. Under the same experimental conditions the corresponding values for human colon cancer HT-29 cells and for rat normal intestinal IEC-6 cells were 5.0% and 8.1%, respectively. The extract fractions enriched with higher oligomers exhibited the highest proapoptotic activity. In conclusion, the Japanese quince procyanidins exhibited proapoptotic activity in Caco-2 cells within a submilimolar concentration range.

Terpenoids as potential chemopreventive and therapeutic agents in liver cancer

Despite significant advances in medicine, liver cancer, predominantly hepatocellular carcinoma remains a major cause of death in the United States as well as the rest of the world. As limited treatment options are currently available to patients with liver cancer, novel preventive control and effective therapeutic approaches are considered to be reasonable and decisive measures to combat this disease. Several naturally occurring dietary and non-dietary phytochemicals have shown enormous potential in the prevention and treatment of several cancers, especially those of the gastrointestinal tract. Terpenoids, the largest group of phytochemicals, traditionally used for medicinal purposes in India and China, are currently being explored as anticancer agents in clinical trials. Terpenoids (also called "isoprenoids") are secondary metabolites occurring in most organisms, particularly plants. More than 40 000 individual terpenoids are known to exist in nature with new compounds being discovered every year. A large number of terpenoids exhibit cytotoxicity against a variety of tumor cells and cancer preventive as well as anticancer efficacy in preclinical animal models. This review critically examines the potential role of naturally occurring terpenoids, from diverse origins, in the chemoprevention and treatment of liver tumors. Both in vitro and in vivo effects of these agents and related cellular and molecular mechanisms are highlighted. Potential challenges and future directions involved in the advancement of these promising natural compounds in the chemoprevention and therapy of human liver cancer are also discussed.

Combinational Effects of Prebiotics and Soybean against Azoxymethane-Induced Colon Cancer In Vivo

Prebiotic fructans are nondigestible carbohydrates with numerous health benefits. Soybean is a rich source of phytonutrients such as isoflavones. The objective of this study was to evaluate the chemopreventive effects of prebiotics (Synergy1) and soybean meal (SM) at 5% and 10% levels alone and in combination on azoxymethane- (AOM-) induced colon carcinogenesis. After one wk of acclimatization, Fisher 344 male rats (N = 90) were randomly assigned to 9 groups (n = 10). Control rats (C) were fed AIN-93G/M. Two s/c injections of AOM were administered to rats at 7 and 8 wk of age at 16 mg/kg body weight. Rats were killed by CO(2) asphyxiation at 45 wk. Tumor incidence (%) in treatment groups ranged from 40 to 75 compared to 100 in C. Results indicate that feeding prebiotics and soybean in combination significantly reduced incidence of AOM-induced colon tumors with implications for food industry in the food-product development.

Melatonin levels, determined by LC-ESI-MS/MS, fluctuate during the day/night cycle in Vitis vinifera cv Malbec: evidence of its antioxidant role in fruits

The identification of melatonin in plants has inspired new investigations to understand its biological function and which endogenous and external factors control its levels in these organisms. Owing to the therapeutical and nutraceutical properties of melatonin, it should be important to develop reliable analytical methods for its quantification in vegetal matrices containing this indoleamine, such as grape and wine. The main objectives of the present study were to test whether melatonin levels fluctuate during the day in berry skins of Vitis vinifera L. cv Malbec, thereby possibly relating its abundance to its putative antioxidant function, to determine whether daylight reaching clusters negatively controls melatonin levels, and to evaluate whether total polyphenols and anthocyanins also change through a 24-hr period. Grapes were harvested throughout the day/night to determine the moment when high levels of these components are present in grapes. The presence of melatonin in grapes was evaluated by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. It is shown for the first time that melatonin levels fluctuate during the day/night cycle in plants grown under field conditions in a fruit organ of the species Vitis vinifera. We also determined that the diurnal decay of melatonin in berry skins is induced by sunlight, because covered bunches retained higher melatonin levels than exposed ones, thus explaining at least part of the basis of its daily fluctuation. Evidence of melatonin's antioxidant role in grapes is also suggested by monitoring malondialdehyde levels during the day.

Resveratrol and black tea polyphenol combination synergistically suppress mouse skin tumors growth by inhibition of activated MAPKs and p53

Cancer chemoprevention by natural dietary agents has received considerable importance because of their cost-effectiveness and wide safety margin. However, single agent intervention has failed to bring the expected outcome in clinical trials; therefore, combinations of chemopreventive agents are gaining increasing popularity. The present study aims to evaluate the combinatorial chemopreventive effects of resveratrol and black tea polyphenol (BTP) in suppressing two-stage mouse skin carcinogenesis induced by DMBA and TPA. Resveratrol/BTP alone treatment decreased tumor incidence by ∼67% and ∼75%, while combination of both at low doses synergistically decreased tumor incidence even more significantly by ∼89% (p<0.01). This combination also significantly regressed tumor volume and number (p<0.01). Mechanistic studies revealed that this combinatorial inhibition was associated with decreased expression of phosphorylated mitogen-activated protein kinase family proteins: extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase 1/2, p38 and increased in total p53 and phospho p53 (Ser 15) in skin tissue/tumor. Treatment with combinations of resveratrol and BTP also decreased expression of proliferating cell nuclear antigen in mouse skin tissues/tumors than their solitary treatments as determined by immunohistochemistry. In addition, histological and cell death analysis also confirmed that resveratrol and BTP treatment together inhibits cellular proliferation and markedly induces apoptosis. Taken together, our results for the first time lucidly illustrate that resveratrol and BTP in combination impart better suppressive activity than either of these agents alone and accentuate that development of novel combination therapies/chemoprevention using dietary agents will be more beneficial against cancer. This promising combination should be examined in therapeutic trials of skin and possibly other cancers.

Tofu (soybean curd) lowers serum lipid levels and modulates hepatic gene expression involved in lipogenesis primarily through its protein, not isoflavone, component in rats

Although soy foods are recommended to prevent hyperlipidemia and related diseases, it is unclear how their active ingredients exert their effects. Here, the effects of tofu (soybean curd) and its putative active components, protein and isoflavone, on lipid metabolism in male rats were compared. Tofu and soy protein significantly lowered serum triacylglycerol and cholesterol levels compared to casein and, through microarray analyses, were found to exclusively alter transcriptomes involved in fatty acid and/or steroid synthesis in the liver, where most of the serum lipids are synthesized. In contrast, isoflavone supplementation had little effect on serum lipid levels or gene expression and exerted no synergistic effects with soy protein or tofu. The importance of the proteinaceous components was further confirmed by the lower activity of enzymes involved in lipogenesis. From these findings it was concluded that the protein, not isoflavone, fraction of soy reduces lipogenesis in liver through gene expression and that this may result in lower serum lipid levels.

Chemopreventive effect of dietary polyphenols in colorectal cancer cell lines

Colorectal cancer (CRC) is the second most fatal and the third most diagnosed type of cancer worldwide. Despite having multifactorial causes, most CRC cases are mainly determined by dietary factors. In recent years, a large number of studies have attributed a protective effect to polyphenols and foods containing these compounds (fruits and vegetables) against CRC. Indeed, polyphenols have been reported to interfere with cancer initiation, promotion, and progression, acting as chemopreventive agents. The aim of this review is to summarize the main chemopreventive properties of some polyphenols (quercetin, rutin, myricetin, chrysin, epigallocatechin-3-gallate, epicatechin, catechin, resveratrol, and xanthohumol) against CRC, observed in cell culture models. From the data reviewed in this article, it can be concluded that these compounds inhibit cell growth, by inducing cell cycle arrest and/or apoptosis; inhibit proliferation, angiogenesis, and/or metastasis; and exhibit anti-inflammatory and/or antioxidant effects. In turn, these effects involve multiple molecular and biochemical mechanisms of action, which are still not completely characterized. Thus, caution is mandatory when attempting to extrapolate the observations obtained in CRC cell line studies to humans.

Bioavailability of the glucuronide and sulfate conjugates of genistein and daidzein in breast cancer resistance protein 1 knockout mice

The dietary polyphenols genistein and daidzein are potent effectors of biological processes. The plasma profile of both isoflavones is governed by the presence of phase II conjugates, mainly glucuronides and sulfates. Breast cancer resistance protein (ABCG2/BCRP) interacts with genistein and daidzein, which are among the natural substrates of the transporter and competitively inhibit ABCG2-mediated drug efflux. ABCG2/BCRP can also transport glucuronide and sulfate conjugates. In this study, we analyzed the plasma levels of aglycones and derived conjugated metabolites, glucuronides, and sulfates, after intragastric administration of these isoflavones to wild-type and Bcrp1(-/-) knockout mice. The results show that overall plasmatic profile is mainly governed by sulfate and glucuronide derivatives, the concentration of which was significantly increased (7- to 10-fold) in Bcrp1(-/-) mice. The total AUC h nM (0-180 min), as the sum of aglycones, glucuronides, and sulfates, was 901 ± 207 in wild-type mice versus 4988 ± 508 in Bcrp1(-/-) mice after genistein administration (50 mg/kg b.wt.); 584.3 ± 90 in wild-type mice versus 4012 ± 612 in Bcrp1(-/-) after daidzein administration (50 mg/kg); and 926 ± 140 in wild-type mice versus 5174 ± 696 in Bcrp1(-/-) after genistein+daidzein administration (25 + 25 mg/kg). Therefore, our results indicate a direct and conclusive Bcrp1 efflux action on phase II metabolites of these isoflavones in vivo and suggest a possible novel concept for ABCG2/BCRP as part of metabolism-driven efflux transport of these conjugates.

Mitochondrial pathway mediates the antileukemic effects of Hemidesmus indicus, a promising botanical drug

Background

Although cancers are characterized by the deregulation of multiple signalling pathways, most current anticancer therapies involve the modulation of a single target. Because of the enormous biological diversity of cancer, strategic combination of agents targeted against the most critical of those alterations is needed. Due to their complex nature, plant products interact with numerous targets and influence several biochemical and molecular cascades. The interest in further development of botanical drugs has been increasing steadily and the FDA recently approved the first new botanical prescription drug. The present study is designed to explore the potential antileukemic properties of Hemidesmus indicus with a view to contributing to further development of botanical drugs. Hemidesmus was submitted to an extensive in vitro preclinical evaluation.

Methodology/Principal Findings

A variety of cellular assays and flow cytometry, as well as a phytochemical screening, were performed on different leukemic cell lines. We have demonstrated that Hemidesmus modulated many components of intracellular signaling pathways involved in cell viability and proliferation and altered the protein expression, eventually leading to tumor cell death, mediated by a loss of mitochondrial transmembrane potential and increased Bax/Bcl-2 ratio. ADP, adenine nucleotide translocator and mitochondrial permeability transition pore inhibitors did not reverse Hemidesmus-induced mitochondrial depolarization. Hemidesmus induced a significant [Ca²⁺]_i raise through the mobilization of intracellular Ca²⁺ stores. Moreover, Hemidesmus significantly enhanced the antitumor activity of three commonly used chemotherapeutic drugs (methotrexate, 6-thioguanine, cytarabine). A clinically relevant observation is that its cytotoxic activity was also recorded in primary cells from acute myeloid leukemic patients.

Conclusions/Significance

These results indicate the molecular basis of the antileukemic effects of Hemidesmus and identify the mitochondrial pathways and [Ca²⁺]_i as crucial actors in its anticancer activity. On these bases, we conclude that Hemidesmus can represent a valuable tool in the anticancer pharmacology, and should be considered for further investigations.

Estimated dietary intakes of flavonols, flavanones and flavones in the European Prospective Investigation into Cancer and Nutrition (EPIC) 24 hour dietary recall cohort

Flavonols, flavanones and flavones (FLAV) are sub-classes of flavonoids that exert cardioprotective and anti-carcinogenic propertiesin vitroandin vivo. We aimed to estimate the FLAV dietary intake, their food sources and associated lifestyle factors in ten European countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. FLAV intake and their food sources for 36 037 subjects, aged between 35 and 74 years, in twenty-seven study centres were obtained using standardised 24 h dietary recall software (EPIC-SOFT). Anad hocfood composition database on FLAV was compiled using data from US Department of Agriculture and Phenol-Explorer databases and was expanded using recipes, estimations and flavonoid retention factors in order to increase its correspondence with the 24 h dietary recall. Our results showed that the highest FLAV-consuming centre was the UK health-conscious group, with 130·9 and 97·0 mg/d for men and women, respectively. The lowest FLAV intakes were 36·8 mg/d in men from Umeå and 37·2 mg/d in women from Malmö (Sweden). The flavanone sub-class was the main contributor to the total FLAV intake ranging from 46·6 to 52·9 % depending on the region. Flavonols ranged from 38·5 to 47·3 % and flavones from 5·8 to 8·6 %. FLAV intake was higher in women, non-smokers, increased with level of education and physical activity. The major food sources were citrus fruits and citrus-based juices (especially for flavanones), tea, wine, other fruits and some vegetables. We concluded that the present study shows heterogeneity in intake of these three sub-classes of flavonoids across European regions and highlights differences by sex and other sociodemographic and lifestyle factors.