Polyphenols: food sources and bioavailability

Bioavailability of Apigenin from Apiin-Rich Parsley in Humans

AIM

Absorption and excretion of apigenin after the ingestion of apiin-rich food, i.e. parsley, was tested.

METHODS

Eleven healthy subjects (5 women, 6 men) in the age range of 23-41 years and with an average body mass index of 23.9 +/- 4.1 kg/m2 took part in this study. After an apigenin- and luteolin-free diet, a single oral bolus of 2 g blanched parsley (corresponding to 65.8 +/- 15.5 micromol apigenin) per kilogram body weight was consumed. Blood samples were taken at 0, 4, 6, 7, 8, 9, 10, 11 and 28 h after parsley consumption and 24-hour urine samples were collected. Apigenin was analyzed in plasma, urine and red blood cells by means of HPLC-ECD.

RESULTS

On average, a maximum apigenin plasma concentration of 127 +/- 81 nmol/l was reached after 7.2 +/- 1.3 h with a high range of variation between subjects. For all participants, plasma apigenin concentration rose after bolus ingestion and fell within 28 h under the detection limit (2.3 nmol/l). The average apigenin content in 24-hour urine was 144 +/- 110 nmol/24 h corresponding to 0.22 +/- 0.16% of the ingested dose. The flavone could be detected in red blood cells without showing dose-response characteristics.

CONCLUSIONS

A small portion of apigenin provided by food reaches the human circulation and, therefore, may reveal biological effects.

Selected diet and lifestyle factors are associated with estrogen metabolites in a multiracial/ethnic population of women

Diet and lifestyle factors, body size, and smoking behavior may influence estrogen metabolism, but the nature of these relations may vary according to race/ethnic groups. We evaluated the association of lifestyle factors with estrogen metabolites 2-hydroxyestrone (2-OHE1) and 16alpha-hydroxyestrone (16alpha-OHE1) in a racially diverse population. With a cross-sectional study design, urine samples from 1881 African-American, Caucasian, Chinese, Japanese, and Hispanic women, aged 42-52 y, from the Study of Women's Health Across the Nation (SWAN) were assayed by EIA for 2-OHE1 and 16alpha-OHE1. Dietary factors and beverages were measured using a modified Block FFQ. Dietary fiber, vegetable and fruit servings, Brassica vegetables, polyphenols, coffee, caffeine, green and black tea, and total alcohol and wine were related to metabolite values using multiple variable regression analyses. In adjusted analyses, 2-OHE1 concentrations were significantly associated with race/ethnicity, weight, smoking, and consumption of hydroxybenzoic acid, anthocyanidins, wine, and caffeine (P < 0.05). Regression models incorporating these variables explained 19-20% of the variation in 2-OHE1 concentrations. Regression models for 16alpha-OHE1, which explained 16-17% of the variability, included race/ethnicity, smoking, caffeine, total dietary fiber, and fiber from fruits and vegetables as variables. These associations may reflect why increased consumption of polyphenol-containing foods and fruit as well as decreased smoking, caffeine intake, and body size would be consistent with hypothesized benefits and risks for selected health outcomes.

Rates of intestinal absorption of molybdenum in humans

The intestinal absorption of molybdenum in healthy human volunteers has been measured by simultaneous oral and intravenous administration of the stable isotopes 95Mo and 96Mo, and the results were analysed using the convolution integral technique. The results showed that molybdenum ingested in liquid form was rapidly and totally absorbed into the circulation under ordinary intake regimes. The rates and extent of absorption were lower for composite meals, and also for increasing levels of administration. This information can be helpful in the application of the new ICRP model of the human alimentary tract.

Ontogenic profiling of glucosinolates, flavonoids, and other secondary metabolites in Eruca sativa (salad rocket), Diplotaxis erucoides (wall rocket), Diplotaxis tenuifolia (wild rocket), and Bunias orientalis (Turkish rocket)

As an influence of the Mediterranean diet, rocket species such as Eruca sativa L., Diplotaxis species, and Bunias orientalis L. are eaten all over the world at different ontogenic stages in salads and soups. They are all species within the plant order Capparales (glucosinolate-containing species), and all are from the family Brassicaceae. Predominantly, the leaves of these species are eaten raw or cooked, although Eruca flowers are also consumed. There is considerable potential with raw plant material for a higher exposure to bioactive phytochemicals such as glucosinolates, their hydrolysis products, and also phenolics, flavonoids, and vitamins such as vitamin C. These compounds are susceptible to ontogenic variation, and the few published studies that have addressed this topic have been inconsistent. Thus, an ontogenic study was performed and all samples were analyzed using a previously developed robust liquid chromatography/mass spectrometry method for the identification and quantification of the major phytochemicals in all tissues of the rocket species. Seeds and roots of both Eruca and Diplotaxis contained predominantly 4-methylthiobutylglucosinolate. Leaves of Eruca and Diplotaxis contained high amounts of 4-mercaptobutylglucosinolate with lower levels of 4-methylthiobutlyglucosinolate and 4-methylsulfinylbutylglucosinolate. Flowers of Eruca and Diplotaxiscontained predominantly 4-methylsulfinylbutyl-glucosinolate. In addition, roots of both Diplotaxisspecies contained 4-hydroxybenzylglucosinolate but 4-hydroxybenzylglucosinolate was absent from roots of Eruca. Seeds and seedlings of all Eruca contained N-heterocyclic compounds but no sinapine, whereas Diplotaxis contained sinapine but not the N-heterocycles. In all tissues of B. orientalis, 4-hydroxybenzylglucosinolate and 4-methylsulfinyl-3-butenylglucosinolate were predominant. All rocket tissues, except roots, contained significant levels of polyglycosylated flavonoids, with/without hydroxycinnamoyl acylation. The core aglycones were kaempferol, quercetin, and isorhamnetin. The exception was B. orientalis, which had a negligible seed flavonoid content as compared with the other species. Anthocyanins were only detected in Eruca flowers and consisted of a complex pattern of at least 16 different anthocyanins.

Microbial metabolism. Part 6. Metabolites of 3- and 7-hydroxyflavones

Fermentation of 3-hydroxyflavone (1) with Beauveria bassiana (ATCC 13144) yielded 3,4'-dihdroxyflavone (3), flavone 3-O-beta-D-4-O-methylglucopyranoside (4) and two minor metabolites. 7-Hydroxyflavone (2) was transformed by Nocardia species (NRRL 5646) to 7-methoxyflavone (5) whilst Aspergillus alliaceus (ATCC 10060) converted it to 4',7-dihydroxyflavone (6). Flavone 7-O-beta-D-4-O-metylglucopyranoside (7) and 4'-hydroxyflavone 7-O-beta-D-4-O-methylglucopyranoside (8) were the metabolic products of 7-hydroxyflavone (2) when fermented with Beauveria bassiana (ATCC 7159). One of the minor metabolites of 3-hydroxyflavone (1) was tentatively assigned a beta'-chalcanol structure (9). Compounds 4, 7 and 8 are reported as new compounds. Structure elucidation of the metabolites was based on spectroscopic data.

Evaluation of the antioxidant properties and bioavailability of free and bound phenolic acids from Trichilia emetica Vahl

Trichilia emetica Vahl. is commonly used in folk medicine of Mali for the treatment of various diseases. In this study, the content and the antioxidant activity of phenolic acids from Trichilia emetica root were evaluated. Free phenolic acids were extracted with a mixture of methanol and 10% acetic acid. Bound phenolic acids were released using first alkaline and then acid hydrolysis. All fractions were quantified separately by HPLC. After alkaline hydrolysis, a remarkable increase in caffeic acid, ferulic acid, p-coumaric acid, syringic acid, vanillic acid, protocathecuic acid and gallic acid content was observed, showing that most of phenolic acids in the drug are present as bound forms. Moreover, the extracts submitted to alkaline hydrolysis showed high antioxidant properties in two in vitro assays: autooxidation of methyl linoleate (MeLo) and ascorbate/Fe(2+)-mediated lipid peroxidation in rat microsomes. An in vivo study was also performed to investigate the intestinal absorption of phenolic acids after oral administration of Trichilia emetica extracts. Results showed high levels of phenolic acids, free or conjugated to glucuronide, in the plasma of rats treated with the hydrolyzed extract. Due to the absence of chlorogenic acid in plasma samples, the presence of caffeic acid seems to be derived from hydrolysis of chlorogenic acid in the gastrointestinal tract.

Pharmacological Perspectives on the Detoxification of Plant Secondary Metabolites: Implications for Ingestive Behavior of Herbivores

Plant secondary metabolites (PSMs) are a major constraint to the ingestion of food by folivorous and browsing herbivores. Understanding the way in which mammalian detoxification pathways are adapted to deal with PSMs is crucial to understanding how PSMs influence ingestive behavior of herbivores and hence their fitness and the impact that they have on vegetation. Pharmacological concepts can provide insights into the relationship between the absorption and metabolic fate of PSMs and ingestive behavior. Lipophilic PSMs will be absorbed into the bloodstream and must be removed fast enough to prevent their accumulation to toxic levels. Elimination depends on their metabolism, usually by cytochrome P450 enzymes, to more polar metabolites that can be excreted by the kidney. The concentration of PSM in blood (C) is a better measure of exposure to a toxin compared to the amount ingested because there can be great variability in the rate and degree of absorption from the gut. C rises and falls depending on the relative rates of absorption and elimination. These rates depend in part on metabolic and transport processes that are saturable and liable to inhibition and induction by PSMs, indicating that complex interactions are likely. Herbivores can use diet choice and the rate and amount of PSM consumption to prevent C from reaching a critical level that produces significant adverse effects.

Flavonoid classes and risk of peripheral arterial occlusive disease: a case-control study in Greece

OBJECTIVE

To assess the relation between specific flavonoid classes and peripheral arterial occlusive disease (PAOD), an important manifestation of atherosclerosis.

DESIGN

Using data from a case-control study conducted in Greece in 1980 on the nutritional epidemiology of PAOD, we have exploited recently published databases on the content of foods in specific flavonoid classes to assess the relation between intake of these compounds and PAOD.

SETTING

A major teaching hospital in Athens, Greece.

SUBJECTS

Cases were 100 patients with PAOD and controls 100 patients with minor surgical conditions admitted to the same hospital.

INTERVENTIONS

No interventions. All cases and controls were interviewed in the hospital wards, and a 110-food item semiquantitative food frequency questionnaire was administered by the same interviewer.

RESULTS

Flavonols, flavones and perhaps flavan-3-ols were inversely associated with PAOD risk, the odds ratios (and 95% confidence intervals) for increments equal to the corresponding standard deviations being 0.41 (0.20-0.86), 0.56 (0.32-0.96) and 0.53 (0.26-1.05), respectively. Total flavonoids were also significantly inversely associated with PAOD.

CONCLUSIONS

On the basis of these results, the biological properties of flavonoids and evidence concerning their relation to other manifestations of atherosclerosis, we conclude that dietary intake of specific classes of flavonoids, as well as total flavonoids, may have a protective effect against PAOD.

SPONSORSHIP

This study was partially supported by a grant to Harvard University by the Samourkas Foundation.

Influence of dietary antioxidants on polyphenol intestinal absorption and metabolism in rats

The ingestion of complex foodstuff implicates the simultaneous presence along the digestive tract of several antioxidants micronutrients. This work aimed to determine if the interactions that may occur at the digestive level between polyphenols and other antioxidant micronutrients may modulate the fate of polyphenols in the splanchnic area. This study was conducted in a rat in situ intestinal perfusion model. Polyphenols (gallic and caffeic acids, catechin, and naringenin) were perfused with or without an antioxidant cocktail. For gallic acid, a significant reduction (-20%) of its net transfer through the brush border associated with a drastic decrease of its intestinal secretion of conjugates (-90%) was observed. By contrast, the transfer of catechin through the brush border increased (18%) and the secretion of its conjugates was twice in the presence of the antioxidants. Perfused polyphenols largely differed in their respective biliary secretion, but these fluxes were not modified by the presence of the antioxidant cocktail. Finally, the simultaneous presence in the small intestine of polyphenols and other dietary antioxidants never affects polyphenol splanchnic metabolism but may modify their intestinal transport without noticeable consequence on their final availability for peripheral tissues.

Preparative isolation and NMR characterization of carboxypyranoanthocyanins

Three pyranoanthocyanins, the 3-glucosides of 5-carboxypyranodelphinidin (2), 5-carboxypyranopetunidin (4), and 5-carboxypyranomalvidin (6), were produced by nucleophilic addition of pyruvic acid to a purified extract of black beans (Phaseolus vulgaris) containing a mixture of the 3-glucosides of delphinidin (1), petunidin (3), and malvidin (5). A Sephadex LH-20 column was used for preparative separation of both pyranoanthocyanins and anthocyanins. The optimum solvent used for isocratic separation was 20% methanol containing 0.5% trifluoroacetic acid. The chromatographic method applied on the pigment mixture yielded in a one-step separation pigments 1-6, with purities up to 98, 89, 99, 87, 55, and 81%, respectively. The structures of 2 and 4, which previously have been tentatively identified mainly by mass spectrometric data acquired from pigment mixtures in wine samples or modified blueberry extract, were confirmed in the present study by two-dimensional nuclear magnetic resonance spectroscopy.

Common sources and estimated intake of plant sterols in the Spanish diet

Plant sterols (PS) are minor lipid components of plants, which may have potential health benefits, mainly based in their cholesterol-lowering effect. The aim of this study was to determine the composition and content of PS in plant-based foods commonly consumed in Spain and to estimate the PS intake in the Spanish diet. For this purpose, the determination of PS content, using a modern methodology to measure free, esterified, and glycosidic sterol forms, was done. Second, an estimation of the intake of PS, using the Spanish National Food Consumption data, was made. The daily intake per person of PS--campesterol, beta-sitosterol, stigmasterol, and stigmastanol--in the Spanish diet was estimated at 276 mg, the largest component being beta-sitosterol (79.7%). Other unknown compounds, tentatively identified as PS, may constitute a considerable potential intake (99 mg). When the daily PS intake among European diets was compared in terms of campesterol, beta-sitosterol, stigmasterol, and stigmastanol, the PS intake in the Spanish diet was in the same range of other countries such as Finland (15.7% higher) or The Netherlands (equal). However, some qualitative differences in the PS sources were detected, that is, the predominant brown bread and vegetable fat consumption in the northern diets versus the white bread and vegetable oil consumption in the Spanish diet. These differences may help to provide a link between the consumption of PS and healthy effects of the diet.

Cocoa polyphenols inhibit phorbol ester-induced superoxide anion formation in cultured HL-60 cells and expression of cyclooxygenase-2 and activation of NF-kappaB and MAPKs in mouse skin in vivo

We investigated the antioxidant and antiinflammatory activities of a flavonoid-rich polyphenolic fraction of cocoa. Cocoa polyphenol (CP) was fractionated from commercial cocoa powder and contained 468 mg/g of gallic acid-equivalent phenolics and 413 mg/g epicatechin-equivalent flavonoids. CP exhibited a dose-dependent free radical-scavenging activity as determined by both 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2'-diphenyl-1-picrylhydrazyl radical scavenging assays. CP also dose-dependently inhibited xanthine oxidase activity and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced superoxide-anion generation in cultured human promyeolcytic leukemia HL-60 cells. Oral administering of CP (4, 20, 40, and 200 mg/kg body weight) to ICR mice 1 h prior to TPA (10 nmol) inhibited ear edema at 5 h in a dose-dependent manner. The levels of COX-2 expression induced in mouse skin after 4-h treatment with topical TPA (10 nmol) was also diminished significantly by pretreating CP (40 or 200 mg/kg) for 30 min. CP at the same doses inhibited TPA-induced nuclear translocation of p65 and subsequent DNA binding of NF-kappaB at 1 h by blocking the degradation of IkappaBalpha in mouse skin. Moreover, phosphorylation of p38 mitogen-activated protein kinase in ICR mouse skin, measured 4 h after TPA treatment, was suppressed by oral pretreatment of CP (40 or 200 mg/kg). Although extracellular signal-regulated protein kinase 1/2 phosphorylation was unaffected, CP inhibited the catalytic activity of extracellular signal-regulated protein kinase 1/2 in TPA-stimulated mouse skin. Since cellular proinflammatory and prooxidant states are closely linked to tumor promotion, the antioxidant and antiinflammatory properties of CP may constitute the basis of possible antitumor promoting effects of this phytochemical.

Soy isoflavones modulate immune function in healthy postmenopausal women

BACKGROUND

The immune system may be compromised after menopause because of the effects of aging and diminishing concentrations of estrogen, an immune-modulating hormone. Isoflavones, plant-derived compounds with estrogenic and antioxidant properties, may offer immunologic benefits to women during this stage of life.

OBJECTIVE

The objective of this study was to evaluate the effects of soy isoflavones, both in soymilk and in supplement form, on markers of immunity and oxidative stress in postmenopausal women.

DESIGN

Postmenopausal women aged 50-65 y (n = 52) enrolled in this 16-wk double-blind, placebo-controlled trial were randomly assigned to 1 of 3 experimental groups: 1) control, 706 mL cow milk/d plus a placebo supplement; 2) soymilk, 71.6 mg isoflavones derived from 706 mL soymilk/d plus a placebo supplement; and 3) supplement, 70 mg isoflavones in a supplement plus 706 mL cow milk/d. Plasma and 24-h urine samples were obtained at baseline and at 16 wk. Immune variables included lymphocyte subsets, cytokine production, and markers of inflammation and oxidative damage.

RESULTS

Isoflavone intervention in postmenopausal women resulted in higher (P < 0.05) B cell populations and lower (P < 0.05) plasma concentrations of 8-hydroxy-2-deoxy-guanosine, an oxidative marker of DNA damage. Isoflavone treatment did not significantly influence concentrations of interferon gamma, interleukin 2, tumor necrosis factor alpha, or C-reactive protein in plasma or of 8-isoprostane in urine.

CONCLUSIONS

Soymilk and supplemental isoflavones modulate B cell populations and appear to be protective against DNA damage in postmenopausal women.

Flavonoids inhibit the amidolytic activity of human thrombin

The effect of a group of natural flavonoids on human thrombin amidolytic activity was investigated using a spectrophotometric inhibition assay while information on the kinetics and thermodynamics was obtained using optical biosensor techniques. All the flavonoids tested acted as reversible inhibitors, and the quercetin-thrombin complex was found to be most stable at pH=7.5. Docking analysis indicated that quercetin's inhibitory behavior could be related to its planar structure and low steric hindrance, and to its ability to form a critical H-bond with thrombin His57.

Solvent-free lipase-catalyzed preparation of long-chain alkyl phenylpropanoates and phenylpropyl alkanoates

An enzymatic method was developed for the preparation of medium- or long-chain alkyl 3-phenylpropenoates (alkyl cinnamates), particularly alkyl hydroxy- and methoxy-substituted cinnamates such as oleyl p-coumarate and oleyl ferulate. The various alkyl cinnamates were formed in high to moderate yield by lipase-catalyzed esterification of cinnamic acid and its analogues with fatty alcohols in vacuo at moderate temperatures in the absence of drying agents and solvents. Immobilized Candida antarctica lipase B was the most effective biocatalyst for the various esterification reactions. The relative esterification activities were of the following order: dihydrocinnamic > cinnamic > 3-methoxycinnamic > dihydrocaffeic approximately 3-hydroxycinnamic > 4-methoxycinnamic > 2-methoxycinnamic > 4-hydroxycinnamic > ferulic approximately 3,4-dimethoxycinnamic > 2-hydroxycinnamic acid. With respect to the position of the substituents at the phenyl moiety, the esterification activity increased in the order meta > para > ortho. Rhizomucor miehei lipase demonstrated moderate esterification activity. Compounds with inverse chemical structure, that is, 3-phenylpropyl alkanoates such as 3-(4-hydroxyphenyl)propyl oleate, were also obtained in high yield by esterification of fatty acids with the corresponding 3-phenylpropan-1-ols.

Gastrointestinal absorption and urinary excretion of trans-cinnamic and p-coumaric acids in rats

trans-Cinnamic acid (CIN) and p-coumaric acid (COU) are ingested by humans in their diet. While the metabolism and health benefits of CIN have been widely documented, little is known about its absorption sites, and there have been few studies dedicated to COU. The gastrointestinal sac technique demonstrated that CIN and COU are absorbed by all digestive organs in rats and partially transported via MCT-mediated carrier. Absorption was lowest in the stomach. Regardless of the organs that were studied, CIN was more efficiently absorbed than COU. After their individual oral administration to rats, CIN and COU were excreted in 0-24 h urine (0.3% and 23% of ingested CIN and COU, respectively). This suggests that COU was less metabolized than CIN. CIN and COU are absorbed across the digestive epithelium and subsequently interact with target tissues. Despite its lower gastrointestinal absorption, COU may have greater health benefits because it seems to be less metabolized than CIN.

The emerging role of flavonoid-rich cocoa and chocolate in cardiovascular health and disease

Cocoa and chocolate have recently been found to be rich plant-derived sources of antioxidant flavonoids with beneficial cardiovascular properties. These favorable physiological effects include: antioxidant activity, vasodilation and blood pressure reduction, inhibition of platelet activity, and decreased inflammation. Increasing evidence from experimental and clinical studies using cocoa-derived products and chocolate suggest an important role for these high-flavanol-containing foods in heart and vascular protection.

Studies on apple and blueberry fruit constituents: Do the polyphenols reach the colon after ingestion?

The aim of our studies was to determine the amount of polyphenols reaching the colon after oral intake of apple juice and blueberries. After a polyphenol-free diet healthy ileostomy volunteers consumed a polyphenol-rich cloudy apple juice while others consumed anthocyanin-rich blueberries. Ileostomy effluent was collected and polyphenols were identified using HPLC-DAD as well as HPLC-ESI-MS/MS; quantification was performed with HPLC-DAD. Most of the orally administered apple polyphenols were absorbed from or metabolized in the small intestine. Between 0 and 33% of the oral dose was recovered in the ileostomy bags with a maximum of excretion after 2 h. A higher amount of the blueberry anthocyanins under study (up to 85%, depending on the sugar moiety) were determined in the ileostomy bags and therefore would reach the colon under physiological circumstances. Such structure-related availability has to be considered when polyphenols are used in model systems to study potential preventive effects in colorectal diseases.

Consumption of Bing sweet cherries lowers circulating concentrations of inflammation markers in healthy men and women

The purpose of this study was to determine the effects of consuming sweet cherries on plasma lipids and markers of inflammation in healthy humans. Healthy men and women (n = 18) supplemented their diets with Bing sweet cherries (280 g/d) for 28 d. After a 12-h fast, blood samples were taken before the start of cherry consumption (study d 0 and 7), 14 and 28 d after the start of cherry supplementation (study d 21 and 35), and 28 d after the discontinuation (study d 64) of cherry consumption. After cherries were consumed for 28 d, circulating concentrations of C-reactive protein (CRP), regulated upon activation, normal T-cell expressed, and secreted (RANTES), and NO decreased by 25 (P < 0.05), 21 (P < 0.05), and 18% (P = 0.07) respectively. After the discontinuation of cherry consumption for 28 d (d 64), concentrations of RANTES continued to decrease (P = 0.001), whereas those of CRP and NO did not differ from either d 7 (pre-cherries) or d 35 (post-cherries). Plasma concentrations of IL-6 and its soluble receptor, intercellular adhesion molecule-1, and tissue inhibitor of metalloproteinases-2 did not change during the study. Cherry consumption did not affect the plasma concentrations of total-, HDL-, LDL-, and VLDL- cholesterol, triglycerides, subfractions of HDL, LDL, VLDL, and their particle sizes and numbers. It also did not affect fasting blood glucose or insulin concentrations or a number of other chemical and hematological variables. Results of the present study suggest a selective modulatory effect of sweet cherries on CRP, NO, and RANTES. Such anti-inflammatory effects may be beneficial for the management and prevention of inflammatory diseases.

The chemopreventive properties of chlorogenic acid reveal a potential new role for the microsomal glucose-6-phosphate translocase in brain tumor progression

Background

Chlorogenic acid (CHL), the most potent functional inhibitor of the microsomal glucose-6-phosphate translocase (G6PT), is thought to possess cancer chemopreventive properties. It is not known, however, whether any G6PT functions are involved in tumorigenesis. We investigated the effects of CHL and the potential role of G6PT in regulating the invasive phenotype of brain tumor-derived glioma cells.

Results

RT-PCR was used to show that, among the adult and pediatric brain tumor-derived cells tested, U-87 glioma cells expressed the highest levels of G6PT mRNA. U-87 cells lacked the microsomal catalytic subunit glucose-6-phosphatase (G6Pase)-α but expressed G6Pase-β which, when coupled to G6PT, allows G6P hydrolysis into glucose to occur in non-glyconeogenic tissues such as brain. CHL inhibited U-87 cell migration and matrix metalloproteinase (MMP)-2 secretion, two prerequisites for tumor cell invasion. Moreover, CHL also inhibited cell migration induced by sphingosine-1-phosphate (S1P), a potent mitogen for glioblastoma multiform cells, as well as the rapid, S1P-induced extracellular signal-regulated protein kinase phosphorylation potentially mediated through intracellular calcium mobilization, suggesting that G6PT may also perform crucial functions in regulating intracellular signalling. Overexpression of the recombinant G6PT protein induced U-87 glioma cell migration that was, in turn, antagonized by CHL. MMP-2 secretion was also inhibited by the adenosine triphosphate (ATP)-depleting agents 2-deoxyglucose and 5-thioglucose, a mechanism that may inhibit ATP-mediated calcium sequestration by G6PT.

Conclusion

We illustrate a new G6PT function in glioma cells that could regulate the intracellular signalling and invasive phenotype of brain tumor cells, and that can be targeted by the anticancer properties of CHL.

Chemical components with health implications in wild and cultivated Mexican common bean seeds (Phaseolus vulgaris L.)

Common bean effects on health have been related to its dietary fiber content and other active compounds. This study assessed the content of flavonoids, coumestrol, phenolic acids, galactooligosaccharides, and phytic acid in wild and cultivated Mexican common bean seeds (raw and cooked) and that of flavonoids, coumestrol, and phenolic acids in germinated bean seeds. The presence of isoflavones in raw bean seeds was not confirmed by the UV spectra. Quercetin, kaempferol, p-coumaric acid, ferulic acid, p-hydroxybenzoic acid, and vanillic acid mean contents were 10.9, 52.3, 10.1, 9.6, 5.4, and 18.2 microg/g, respectively; raffinose, stachyose, verbascose, and phytic acid mean contents were 8.5, 56.3, 5.5, and 11.5 mg/g, respectively, in raw seeds. All compounds were affected by autoclaving, and germination resulted in a de novo synthesis of flavonols, phytoestrogens, and phenolic acids. The impact on health of common bean seed is affected by dietary burden, specific compounds content, and processing. On the other hand, germinated bean seed or beans sprouts may be sources of antioxidants and phytoestrogens.

Soy isoflavones and bone health: a double-edged sword?

Numerous publications and research studies on isoflavones have prompted a nationwide increase in the consumption of soy-based foods and supplements in the United States. Isoflavones are natural endocrine active compounds generally considered to promote health and prevent or slow the onset of certain chronic diseases such as osteoporosis. The beneficial effects of soy isoflavones on bone may, however, be life-stage specific and dependent on the estrogen receptor number and endogenous hormone milieu. Perimenopausal and early menopausal women may therefore be more receptive to the therapeutic effects of isoflavones on bone loss prior to the diminution of estrogen receptors that occurs in the postmenopausal years, whereas laboratory studies in developmental age range animals have demonstrated the potential for adverse effects following exposure to high levels of soy isoflavones. Clinical studies in developing humans that either support or refute findings in animal studies are lacking. The effects of chronic consumption of high levels of soy isoflavones at each life stage to assess risk-benefit ratios should be a high priority of research.

In vitro interactions of water-soluble garlic components with human cytochromes p450

Eight water-soluble components of aged garlic extract were evaluated to assess their potential to inhibit the activity of human cytochrome-P450 (CYP) enzymes. The in vitro model consisted of human liver microsomes with index reactions chosen to profile the activity of the following six CYP isoforms: CYP1A2, 2B6, 2C9, 2C19, 2D6, and 3A. With only 2 exceptions, none of the 8 garlic components produced >50% inhibition even at high concentrations (100 micromol/L). S-methyl-L-cysteine and S-allyl-L-cysteine at 100 micromol/L produced modest inhibition of CYP3A, reducing activity to 20-40% of control. However available clinical evidence does not indicate CYP3A inhibition in vivo. The findings suggest that drug interactions involving inhibition of CYP3A enzymes by aged garlic extract are very unlikely.

Phenolic compounds in coffee

Phenolic compounds are secondary metabolites generally involved in plant adaptation to environmental stress conditions. Chlorogenic acids (CGA) and related compounds are the main components of the phenolic fraction of green coffee beans, reaching levels up to 14 % (dry matter basis). These compounds have a number of beneficial health properties related to their potent antioxidant activity as well as hepatoprotective, hypoglycemic and antiviral activities. The main groups of CGA found in green coffee beans include caffeoylquinic acids, dicaffeoylquinic acids, feruloylquinic acids, p-coumaroylquinic acids and mixed diesters of caffeic and ferulic acids with quinic acid, each group with at least three isomers. During coffee processing, CGA may be isomerized, hydrolyzed or degraded into low molecular weight compounds. The high temperatures of roasting also produce transformation of part of CGA into quinolactones and, along with other compounds, melanoidins. This review focuses on the chemical characteristics, biosynthesis, and distribution of CGA and related compounds in coffee. The influence of genetic, physiological and environmental factors as well as processing on the chemical composition of coffee beans is discussed. The impact of CGA composition of green coffee on cup quality is also approached. Despite the existence of substantial published information on the total levels of CGA in coffee, more research is needed on the composition of minor phenolic compounds and specific CGA isomers (and related substances) in green and roasted coffee beans, as well as their impact on coffee quality.

Polyphenols and gastrointestinal diseases

PURPOSE OF REVIEW

This article will review the role of polyphenols in gastrointestinal diseases. Ingested polyphenols are concentrated in the gastrointestinal tract and are not well absorbed into the rest of the body. Thus, the high luminal concentrations achieved support a potential for therapeutic uses in the gastrointestinal tract. Additionally, there is great interest from the general public in complementary and alternative medicine.

RECENT FINDINGS

Dietary polyphenols are a major source of antioxidants consumed by humans. Polyphenols possess not only antioxidant properties but also antiviral, antibacterial, antiinflammatory and anticarcinogenic effects, as well as the ability to modulate certain signaling pathways such as nuclear factor-kappaB activation. Green tea polyphenols have been shown to have efficacy in various models of inflammatory bowel disease. Silymarin, or milk thistle, is hepatoprotective against many forms of experimental liver injury and is widely used in human liver diseases, such as hepatitis C and alcoholic cirrhosis, with an excellent safety profile (but with unclear efficacy).

SUMMARY

Substantial in-vitro and animal studies support the beneficial effects of polyphenols in many gastrointestinal diseases. Well designed multicenter trials in humans, such as those called for in the 2005 National Institutes of Health Requests for Applications for Silymarin Centers, will be critical for defining the safety, appropriate dosing and therapeutic efficacy of such agents.

Dietary supplementation of baicalin and quercetin attenuates iron overload induced mouse liver injury

The introduction of new iron chelating drugs may ultimately improve iron-chelation therapy for patients with iron overload diseases such as thalassaemia and other disorders. In this paper, the in vivo effects of baicalin and quercetin on iron overload induced liver injury were studied on mice. It was found that when iron-dextran induced iron overload mice were fed baicalin or quercetin containing diet (1% w/w) for 45 days, both flavonoids significantly inhibited iron overload induced lipid peroxidation and protein oxidation of liver, decreased hepatic iron and hepatic collagen content, increased the serum non-heme iron level but not serum ferritin level. Flavonoids supplementation also increased the excretion of iron through feces. In vitro study demonstrated that both flavonoids could release iron from ferritin. These results indicate that besides acting as antioxidants, both flavonoids can also release iron from liver and finally excrete it through feces. The present study provides further support for flavonoids to be medicines for iron overload diseases.

Anti-thrombotic effect of strawberries

Because of the high mortality, prevention of arterial thrombotic disease has top priority in developed countries. As inappropriate diet is known to predispose to acute thrombotic events, regular intake of an anti-thrombotic diet may offer a convenient and effective method of prevention. As part of a systematic investigation into the anti-thrombotic effect of fruits and vegetables, strawberry varieties were tested in this study. An in vitro platelet function test (haemostatometry) was used for screening strawberry filtrates. Those that showed significant antiplatelet effect were further assessed with a laser-induced thrombosis test in mice. Measurement of flow-mediated vasodilation in the femoral artery of mice reflected the effect on the vascular endothelium. Correlation between the effects on platelet reactivity in vitro and the antioxidant activity (hypoxanthine/xanthine oxidase test) or phenolic compound content was assessed. Strawberry varieties KYSt-4 (Nohime), KYSt-11 (Kurume IH-1) and KYSt-17 (Kurume 58) showed significant antiplatelet activity both in vitro and, after oral administration, in vivo. Both KYSt-11 and KYSt-17, but not KYSt-4, significantly reduced flow-mediated vasodilation; that is, caused endothelial dysfunction. Antiplatelet activities were heat stable. Significant correlation was found between antiplatelet and antioxidant activities (P=0.049, R=0.23) or total phenolic compounds (P=0.0096, R=0.36). Of the tested strawberry varieties, KYSt-4, KYSt-11 and KYSt-17 showed significant anti-thrombotic effect. The dual mechanism of the effect may involve a direct inhibition of both platelet function and antioxidant activities.

Antioxidant effects of ginsenoside Re in cardiomyocytes

We have previously demonstrated that American ginseng berry extract exhibited significant protection against oxidant-mediated injury in cardiomyocytes. To extend this work, we sought to investigate the antioxidant effects of Re, a protopanaxatriols-type and single chemical integrant present in American ginseng berry extract, using the same chick cardiomyocyte model of oxidant injury as well as ESR spectroscopy in a cell-free chemical system. In cells exposed to 2 h of H2O2 (0.5 mM), pretreatment with Re (0.05, 0.1, or 0.5 mg/ml for 2 h) significantly attenuated 2',7'-dichlorofluorescein (DCF) fluorescence by 51% (from 1345+/-67 to 658+/-46 a.u., P<0.001), and remarkably reduced cell death (from 51.5+/-3.0% to 11.8+/-1.5%, P<0.001, compared to the control). Similar results were also observed in cells exposed to antimycin A (100 microM), a mitochondrial electron transport chain site III inhibitor which increases endogenous oxidative stress. In the ESR study, however, Re failed to reduce the formation of the superoxide/DMPO adduct and DPPH radicals. These results suggest that ginsenoside Re functions as an antioxidant, protecting cardiomyocytes from oxidant injury induced by both exogenous and endogenous oxidants, and that its protective effects may be mostly attributed to scavenging H2O2 and hydroxyl radicals.

Free radical scavenging and antigenotoxic activities of natural phenolic compounds in dried flowers of Hibiscus sabdariffa L

The antioxidant and free radical scavenging effects of two fractions of the ethanolic extract (HSCF, chloroform soluble fraction and HSEA, ethyl acetate soluble fraction) obtained from the dried flowers of Hibiscus sabdariffa L were investigated. The total antioxidant activity of the extracts was estimated to be 4.6 and 8.6 mM of vitamin C for HSCF and HSEA, respectively. Both HSCF and HSEA scavenged hydrogen peroxide (H(2)O(2)) (79-94%) at the dose of 500 microg. Similarly, the extracts showed inhibitory (70-80%) effects on superoxide anions radicals (O(2) (- *)) at a dose of 1000 microg. The concentrations required for a 50% scavenging of hydroxyl radical (OH) (IC(50)) were 380 and 200 microg for HSCF and HSEA, respectively. HSEA and HSCF were better scavengers of O(2) (- *), *OH and H(2)O(2) as compared to BHA, quercetin and alpha-tocopherol. At a concentration of 25 microg/mL HSCF and HSEA exhibited 32 and 38% inhibition on CCl(4)-NADPH-induced lipid peroxidation, respectively, while both extracts exhibited 80 and 89% inhibitory effects at 100 microg/mL. Pretreatment with H. sabdariffa extracts orally with 100 mg/kg and 250 mg/kg simultaneously with intraperitoneal injection FeCl(2)-ascorbic acid-ADP mixture reduced (p < 0.01) the formation of malondialdehyde content. Treatment of rats with HSCF, HSEA and vitamin C (standard antioxidant) significantly inhibited the induction of micronucleated polychromatic erythrocytes by sodium arsenite (2.5 mg/kg) (p < 0.001) after 24 h by 60, 70 and 50%, respectively. The results indicate that extracts of H. sabdariffa showed strong antimutagenic activity and free radical scavenging effects on active oxygen species.

Antioxidant and antiulcerative properties of phenolics from Chinese quince, quince, and apple fruits

To evaluate the health benefits of Chinese quince and quince phenolics, their antioxidant properties and antiulcerative activity were investigated in comparison with apple phenolics as a reference. The strength of antioxidant activity and DPPH radical scavenging activity of these fruit phenolics varied according to different in vitro evaluation systems, whereas the antioxidative property of rat blood increased in all rats orally administered phenolics. Ferulic acid and isoferulic acid were detected as major metabolites in rats given apple phenolics, quince phenolics, and 5-caffeoylquinic acid standard. (-)-Epicatechin and its 3'-O-methyl ether could be detected in rats administered apple phenolics and (-)-epicatechin standard. In the ethanol-induced gastric ulcer, pre-administration of Chinese quince and quince phenolics suppressed the occurrence of gastric lesions in rats, whereas apple phenolics seemed to promote ulceration. The trend of myeloperoxidase activity was similar to that of the ulcer index. The results showed that Chinese quince and quince phenolics might have health benefits by acting both in blood vessels and on the gastrointestinal tract.

Antioxidants and polyunsaturated fatty acids in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). Oligodendrocyte damage and subsequent axonal demyelination is a hallmark of this disease. Different pathomechanisms, for example, immune-mediated inflammation, oxidative stress and excitotoxicity, are involved in the immunopathology of MS. The risk of developing MS is associated with increased dietary intake of saturated fatty acids. Polyunsaturated fatty acid (PUFA) and antioxidant deficiencies along with decreased cellular antioxidant defence mechanisms have been observed in MS patients. Furthermore, antioxidant and PUFA treatment in experimental allergic encephalomyelitis, an animal model of MS, decreased the clinical signs of disease. Low-molecular-weight antioxidants may support cellular antioxidant defences in various ways, including radical scavenging, interfering with gene transcription, protein expression, enzyme activity and by metal chelation. PUFAs may not only exert immunosuppressive actions through their incorporation in immune cells but also may affect cell function within the CNS. Both dietary antioxidants and PUFAs have the potential to diminish disease symptoms by targeting specific pathomechanisms and supporting recovery in MS.

Protective effect of ferulic acid on γ-radiation-induced micronuclei, dicentric aberration and lipid peroxidation in human lymphocytes

In this study we examined radioprotective effect of ferulic acid (FA) on gamma radiation-induced dicentric aberration and lipid peroxidation with reference to alterations in cellular antioxidant status in cultured lymphocytes. To establish most effective protective support we used three different concentrations of FA (1, 5 and 10 microg/ml) and three different doses of gamma-radiation (1, 2 and 4 Gy). Treatment of lymphocytes with FA alone (at 10 microg/ml) gave no significant change in micronuclei (MN), dicentric aberration (DC), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) or glutathione peroxidase (GPx) activities when compared with normal lymphocytes; irradiation at 1, 2 and 4 Gy increased the MN and DC frequencies in a dose-dependent manner. Treatment with FA for 30 min before radiation exposure resulted in a significant decline of MN and DC yields as FA concentration increased. Compared to 1 Gy exposure alone, the extent to which FA (1 microg/ml) reduced the MN and DC yields was 75% and 50%, respectively. With 4 Gy irradiation, FA (10 microg/ml) decreased 45% MN and 25% DC frequencies. FA-pretreated lymphocytes (1, 5 and 10 microg/ml) showed progressively decreased TBARS levels after irradiation. Irradiation (1, 2 and 4 Gy) significantly decreased GSH levels, SOD, CAT and GPx activities in a dose-dependent manner. Pretreatment with 10 microg/ml of FA significantly (p<0.05) prevented the decreases in the radiation-induced GSH, SOD, CAT and GPx activities. These findings suggest potential use and benefit of FA as a radioprotector.

Inhibition of lung cancer cell growth by quercetin glucuronides via G2/M arrest and induction of apoptosis

Lung cancer is the leading cause of cancer death in many developed countries, including Taiwan. Quercetin, a widely distributed bioflavonoid, is well known to induce growth inhibition in a variety of human cancer cells. Quercetin glucuronides are the main circulating metabolites after dietary supplements with quercetin in humans. However, there is little information available as to how quercetin glucuronides affect human cancer cells. We investigated the effects of quercetin glucuronides in a human lung cancer cell line NCI-H209. We checked the cell viability, cell cycle checkpoint proteins, pro- and antiapoptotic proteins, caspase-3 activity, and gene expression by flow cytometry and Western blot. The viability of cells decreased in a dose- and time-dependent manner. Cell cycle analysis revealed a significant increase of the proportion of cells in G2/M phase and subG0/G1 phase (corresponding to apoptotic cells). Moreover, quercetin glucuronides increased the expressions of cyclin B, Cdc25c-ser-216-p, and Wee1 proteins, indicating the G2/M arrest. We also demonstrated a concurrent decrease of the mitochondrial membrane potential, release of cytochrome c, up-regulation of Bax, down-regulation of Bcl-2, and activation of caspase-3, and subsequently, cleavage of poly(ADP-ribose) polymerase. In addition, quercetin glucuronide-induced apoptosis was totally blocked by the broad-spectrum caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone. Taken together, we demonstrated that quercetin glucuronides inhibited proliferation through G2/M arrest of the cell cycle and induced apoptosis via caspase-3 cascade in the human lung cancer cell line NCI-H209. Delineation of the biological effects of specific major quercetin metabolites on chemotherapeutic potential or chemoprevention of human cancers warrants further investigation.

Inhibitory effect of dietary phenolic compounds on Chlamydia pneumoniae in cell cultures

Chlamydial infections are very common worldwide. All chlamydial species have a tendency to cause persistent infections, which have been associated to several chronic diseases including blinding trachoma, infertility and coronary heart disease (CHD). At present, no efficient treatment for the eradication of chronic chlamydial infections exists and, thus, new antichlamydial compounds are urgently needed. This study was designed to screen antichlamydial activity of natural flavonoids and other natural and structurally similar synthetic compounds against Chlamydia pneumoniae in human cell line (HL). HL cells were infected with C. pneumoniae and incubated 72 h with studied compounds. Reduction in the number of inclusions was determined with immunofluorescence staining. In vitro minimum inhibitory concentration was also determined for some of the most active compounds. Thirty seven percentage of the studied compounds (57 in total) were highly active against C. pneumoniae and all the studied compounds were non-toxic to the host cells at studied concentrations. Our study revealed direct antichlamydial effect for selected polyphenolic compounds against C. pneumoniae, in vitro. We also demonstrated the ability of some of the investigated compounds to accumulate inside cells or into cell membranes and cause inhibition, even when present only prior to infection.

Preventive effect of oral administration of 6-(methylsulfinyl)hexyl isothiocyanate derived from wasabi (Wasabia japonica Matsum) against pulmonary metastasis of B16-BL6 mouse melanoma cells

AIM

Effect of oral administration of 6-(methylsulfinyl)hexyl isothiocyanate (6-MITC) or a 6-MITC-containing T-wasabi fraction from wasabi root (Wasabia japonica Matsum) to inhibit the macroscopic pulmonary metastasis was studied with a murine B16-BL6 melanoma model.

METHOD

Two administration routes, subcutaneous or intravenous, and two administration times, prior to or concomitant with tumor inoculation, of 6-MITC or T-wasabi against the metastatic foci formation in C57BL/6J mouse lungs were compared.

RESULTS

The number of metastasized foci per lung in either subcutaneous or intravenous injection was significantly reduced by intake of 6-MITC or a T-wasabi fraction. The maximum reduction by a T-wasabi fraction reached to 82%. Fifty-six percent of foci formation was inhibited by a 2 week-prior administration of 6-MITC (200 microM), whereas only 27% inhibition was obtained by a concomitant administration with tumor inoculation. Neither 6-MITC nor T-wasabi at tested concentrations showed any toxic effects.

DISCUSSION

Together with our previous results, a component of the Japanese pungent spice, wasabi appears to inhibit not only tumor cell growth but also tumor metastasis. Therefore, 6-MITC from wasabi is apparently a useful dietary candidate for controlling tumor progression.

Bilberry Extracts Induce Gene Expression Through the Electrophile Response Element

A number of genes important for detoxification and antioxidant defense induced by mild stress generated by, for example, physical activity/exercise, caloric restriction, or alcohol may provide health benefits by causing the organism to mount such a defense response. More recently, induction of these defenses has also been attributed to phytochemicals or secondary metabolites from dietary plants. Many polyphenols, which constitute a large fraction of these phytochemicals, increase cellular levels of antioxidants, such as glutathione and other components of the detoxification systems, via the transactivation of genes containing electrophile response elements (EpREs) within their promoters. One such gene, gamma-glutamylcysteine synthetase, has previously been shown to be positively regulated by quercetin, a flavonoid found in high concentrations in onions, apples, and bilberries through EpRE transactivation. As a further step, we have investigated whether bilberries and quercetin have the ability to induce transcription of Fos-related antigen 1 (Fra-1), which contains two EpREs in its promoter. Fra-1 is a member of the activator protein 1 (AP-1) family of transcription factors and, due to the lack of transactivation domain Fra-1, can suppress activation of AP-1. We present results demonstrating that extracts from bilberries, and the flavonoid quercetin, abundant in bilberries, induce the fra-1 promoter and the cellular content of Fra-1 mRNA. We further provide evidence that this induction is mediated through EpREs.

Chemopreventive actions of polyphenolic compounds in cancer

Oxidative stress and associated mechanisms involving inflammation, aberrant signaling pathways and gap junction intercellular communication is increasingly associated with the pathogenesis of various chronic degenerative disorders such as atherosclerosis, neurodegeneration and cancer. Consumption of fruits, vegetables and beverages like teas continues to be suggested to have the capacity to reduce the incidence of cancer. The bioactive compounds including phenolics may be responsible for the chemopreventive effects. While the free radical scavenging and antioxidant properties of phenolics are well established, emerging literature reports suggest that their chemopreventive effects may also be ascribed to their ability to modulate components of cell signaling pathways. This paper reviews the potential chemoprevention role of phenolics with a focus on cellular signal transduction mechanisms and prevention of gap junction intercellular communication relevant to cancer.

Moderate acute intake of de-alcoholized red wine, but not alcohol, is protective against radiation-induced DNA damage ex vivo -- results of a comparative in vivo intervention study in younger men

Moderate intake of wine is associated with reduced risk of cardiovascular disease and possibly cancer however it remains unclear whether the potential health benefits of wine intake are due to alcohol or the non-alcoholic fraction of wine. We therefore tested the hypothesis that the non-alcoholic fraction of wine protects against genome damage induced by oxidative stress in a crossover intervention study involving six young adult males aged 21-26 years. The participants adhered to a low plant phenolic compound diet for 48 h prior to consuming 300 mL of complete red wine, de-alcoholized red wine or ethanol on separate occasions 1 week apart. Blood samples were collected 0.5, 1.0 and 2.0 h after beverage consumption. Baseline and radiation-induced genome damage was measured using the cytokinesis-block micronucleus assay and total plasma catechin concentration was measured. Consumption of de-alcoholized red wine significantly decreased the gamma radiation-induced DNA damage at 1 and 2 h post-consumption by 20%. In contrast alcohol tended to increase radiation-induced genome damage and complete wine protected against radiation-induced genome damage relative to alcohol. The observed effects were only weakly correlated with the concentration of total plasma catechin (R=-0.23). These preliminary data suggest that only the non-alcoholic fraction of red wine protects DNA from oxidative damage but this effect cannot be explained solely by plasma catechin.

Luteolin, a flavonoid, inhibits AP-1 activation by basophils

Flavonoids including luteolin, apigenin, and fisetin are inhibitors of IL-4 synthesis and CD40 ligand expression by basophils. This study was done to search for compounds with greater inhibitory activity of IL-4 expression and to clarify the molecular mechanisms through which flavonoids inhibit their expression. Of the 37 flavonoids and related compounds examined, ayanin, luteolin, and apigenin were the strongest inhibitors of IL-4 production by purified basophils in response to anti-IgE antibody plus IL-3. Luteolin did not suppress Syk or Lyn phosphorylation in basophils, nor did suppress p54/46 SAPK/JNK, p38 MAPK, and p44/42 MAPK activation by a basophilic cell line, KU812 cells, stimulated with A23187 and PMA. However, luteolin did inhibit phosphorylation of c-Jun and DNA binding activity of AP-1 in nuclear lysates from stimulated KU812 cells. These results provide a fundamental structure of flavonoids for IL-4 inhibition and demonstrate a novel action of flavonoids that suppresses the activation of AP-1.

Colonic availability of apple polyphenols - A study in ileostomy subjects

Nutrition is thought to play an essential role in the pathogenesis of inflammatory and malignant gastrointestinal diseases. It is well known that plant ingredients such as polyphenols and flavonoids show anticarcinogenic effects both in vitro and in animal experiments, and may thus reduce the risk of colorectal cancer in man. The aim of the study was to determine the amount of polyphenols reaching the colon after oral intake of apple juice. After consumption of a polyphenol-free diet 11 healthy ileostomy volunteers drank 1 L of a polyphenol-rich cloudy apple juice. Ileostomy effluent was collected immediately before and 1, 2, 4, 6, and 8 h after consumption of apple juice. A broad spectrum of polyphenols was identified using HPLC-diode array detection (HPLC-DAD) as well as HPLC-ESI-MS/MS; quantitation was performed with HPLC-DAD. Most of the orally administered apple polyphenols were absorbed from or metabolized in the small intestine. Between 0 and 33% of the oral dose was recovered in the ileostomy bags with a maximum of excretion after 2 h. Phloretin glucuronide as product of polyphenol metabolism was detected in the ileostomy effluent. The present results show that most of the apple juice polyphenols are absorbed in the small intestine. Minor amounts of unmetabolized polyphenols are recovered in the ileostomy effluent, which would reach the colon under physiologic circumstances. These data have to be considered when polyphenols are used in model systems to show preventive effects in colorectal carcinogenesis.

Characterization and quantitation of phenolic compounds in new apricot (Prunus armeniaca L.) varieties

Thirty-seven apricot varieties, including four new releases (Rojo Pasión, Murciana, Selene, and Dorada) obtained from different crosses between apricot varieties and three traditional Spanish cultivars (Currot, Mauricio, and Búlida), were separated according to flesh color into four groups: white, yellow, light orange, and orange (mean hue angles in flesh were 88.1, 85.0, 77.6, and 72.4, respectively). Four phenolic compound groups, procyanidins, hydroxycinnamic acid derivatives, flavonols, and anthocyanins, were identified by HPLC-MS/MS and individually quantified using HPLC-DAD. Chlorogenic and neochlorogenic acids, procyanidins B1, B2, and B4, and some procyanidin trimers, quercetin 3-rutinoside, kaempferol 3-rhamnosyl-hexoside and quercetin 3-acetyl-hexoside, cyanidin 3-rutinoside, and 3-glucoside, were detected and quantified in the skin and flesh of the different cultivars. The total phenolics content, quantified as the addition of the individual compounds quantified by HPLC, ranged between 32.6 and 160.0 mg 100 g(-1) of edible tissue. No correlation between the flesh color and the phenolic content of the different cultivars was observed.

Polyphenol levels in human urine after intake of six different polyphenol-rich beverages

Dietary polyphenols are suggested to participate in the prevention of CVD and cancer. It is essential for epidemiological studies to be able to compare intake of the main dietary polyphenols in populations. The present paper describes a fast method suitable for the analysis of polyphenols in urine, selected as potential biomarkers of intake. This method is applied to the estimation of polyphenol recovery after ingestion of six different polyphenol-rich beverages. Fifteen polyphenols including mammalian lignans (enterodiol and enterolactone), several phenolic acids (chlorogenic, caffeic, m-coumaric, gallic, and 4-O-methylgallic acids), phloretin and various flavonoids (catechin, epicatechin, quercetin, isorhamnetin, kaempferol, hesperetin, and naringenin) were simultaneously quantified in human urine by HPLC coupled with electrospray ionisation mass-MS (HPLC-electrospray-tandem mass spectrometry) with a run time of 6 min per sample. The method has been validated with regard to linearity, precision, and accuracy in intra- and inter-day assays. It was applied to urine samples collected from nine volunteers in the 24 h following consumption of either green tea, a grape-skin extract, cocoa beverage, coffee, grapefruit juice or orange juice. Levels of urinary excretion suggest that chlorogenic acid, gallic acid, epicatechin, naringenin or hesperetin could be used as specific biomarkers to evaluate the consumption of coffee, wine, tea or cocoa, and citrus juices respectively.

In vivo treatment of acute Chlamydia pneumoniae infection with the flavonoids quercetin and luteolin and an alkyl gallate, octyl gallate, in a mouse model

Increasing evidence suggests that plant polyphenolic compounds may protect from cardiovascular diseases, which have been addressed to their antioxidative properties. In addition, these compounds have been shown to possess anti-inflammatory and anti-microbial potential. In the present study we tested the effects of two flavonoid compounds, quercetin and luteolin, and one alkyl gallate, octyl gallate, on the course of acute Chlamydia pneumoniae infection in vivo. C57BL/6J mice were treated with quercetin, luteolin or octyl gallate for 3 days prior to and 10 days after C. pneumoniae inoculation. Lung tissue was analysed for the presence of chlamydia by culture and quantitative PCR, and inflammatory responses were assessed. Luteolin was found histologically to suppress inflammation in lung tissue, the development of C. pneumoniae-specific antibodies and the presence of chlamydia in lung tissue. Octyl gallate had no significant effect on the course of infection, but quercetin increased both the inflammatory responses and the chlamydial load in the lungs. The infection and inflammation-enhancing effects of quercetin treatment may be attributable to the dose and the route of administration and should be reassessed in further studies with lower doses or with different metabolites of the compound. Contrariwise, the effects of luteolin treatment suggest this compound to have potential in decreasing the infection load and inflammatory reactions in vivo.

Novel mechanisms of natural antioxidant compounds in biological systems: involvement of glutathione and glutathione-related enzymes

Polyphenols are wide variety of compounds that occur in fruits and vegetables, wine, tea, extra virgin olive oil, chocolate and other cocoa products. Several polyphenols have been demonstrated to have clear antioxidant properties in vitro, and many of their biological actions have been attributed to their intrinsic reducing capabilities. However, this concept appears now to be a simplistic way to conceive their activity. Evidence is indeed accumulating that polyphenols might exert several other specific biological effects that are as yet poorly understood. In this article we review the most recent data on the subject and describe the additional functions that polyphenols can have in biological systems, focusing on their effects on glutathione and its related enzymes. Experimental data indicate that polyhenols may offer an indirect protection by activating endogenous defense systems. Several lines of evidence suggest a tight connection between exogenous and endogenous antioxidants that appear to act in a coordinated fashion. It is reasonable to hypothesize that this is achieved, at least in part, through antioxidant responsive elements (AREs) present in the promoter regions of many of the genes inducible by oxidative and chemical stress. The latest studies strongly suggest that dietary polyphenols can stimulate antioxidant transcription and detoxification defense systems through ARE.