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Michael Woods
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American Chemical Society

Scientific symposium today on healthful antioxidants in plant-based foods

INDIANAPOLIS, Sept. 9, 2013 — With millions of people tailoring their diets to include more healthful antioxidants — and these "polyphenols" getting tremendous attention among nutritionists, food scientists and physicians — the world's largest scientific society today is holding a symposium on that topic today.

The symposium, called "Polyphenolic Chemistry in Food Science: Flavor, Color, and Biofunctional Properties," is part of the 246th National Meeting & Exposition of the American Chemical Society (ACS). The meeting continues through Thursday in the Indiana Convention Center and downtown hotels. Thousands of scientists and others are expected for the meeting, which features almost 7,000 reports on new discoveries in science and other topics.

Found naturally in plant-based foods — including items with such high levels that they have been termed "superfoods" — polyphenols have been in the news as health food. Superfoods include dark chocolate, red wine, coffee, tea, nuts, and deeply colored fruits and vegetables. Recent scientific research links polyphenols, which are a type of antioxidant, with a range of possible health benefits. Among them: reducing the risk of cardiovascular disease and certain forms of cancer.

Among more than a dozen topics in the symposium:

Abstracts in the symposium appear below.

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A press conference on this topic will be held Tuesday, Sept. 10, at 2 p.m. in the ACS Press Center, Room 211 in the Indiana Convention Center. Reporters can attend in person or access live audio and video of the event and ask questions at http://www.ustream.tv/channel/acslive.

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Abstracts

Isolation and identification of a potent radical scavenger (canolol) from roasted high erucic mustard seed oil and its formation during roasting

Kshitij Shrestha1, Kshitij.Shrestha@UGent.be, Christian V. Stevens2, Bruno De Meulenaer 1, Bruno.DeMeulenaer@UGent.be.(1) Department of Food Safety and Food Quality, NutriFOODchem Unit, Ghent University, Ghent, Non-US/Canada 9000, Belgium, (2) Department of Sustainable Organic Chemistry and Technology, Ghent University, Ghent, Non-US/Canada 9000, Belgium

Roasting of high erucic acid mustard (HEM) seed has been reported to give a typical flavor and increase the oxidative stability of extracted oil. A potent radical scavenging compound was successfully isolated for the first time from roasted HEM seed oil in a single-step chromatographic separation using an amino solid-phase extraction column. Nuclear magnetic resonance, mass spectrometry, ultraviolet and fluorescence spectra revealed the compound as 2,6-dimethoxy-4-vinylphenol (generally known as canolol), and its identity was fully confirmed by chemical synthesis.

The formation of canolol together with the loss of free sinapic acid (FSA) and total sinapic acid after basic hydrolysis (TSAH) during roasting was compared among four HEM varieties (Brassica juncea, Brassica juncea var. oriental, Brassica nigra, and Sinapis alba) and a low erucic acid rapeseed. HEM varieties were shown to produce less than one-third of canolol compared to rapeseed at similar roasting conditions. The amount of canolol formed after roasting was far higher compared to the amount of FSA loss in all the varieties (in molar basis). Therefore, partial hydrolysis of sinapic acid derivatives (SADs) into FSA additionally contributed to canolol formation. The lower amount of canolol formation in HEM varieties compared to rapeseed was linked to a lower free FSA content together with a lower loss of SADs in the HEM varieties. Around 50% of the canolol formed in the roasted seed was shown to be extracted in the oil. Roasting of both HEM seed and rapeseed before oil extraction was found to be a beneficial step to obtain canolol-enriched oil, which could improve the oxidative stability.

Antioxidant efficacy of caffeates in emulsions and the effect of tocopherols

Ann-Dorit Moltke Sřrensen1, adms@food.dtu.dk, Mercedes Alemán2, Erwann Durand3, Pierre Villeneuve3, Charlotte Jacobsen1. (1) Division of Industrial Food Research, National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark, (2) Nutrition and Food Science Department, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain, (3) UMR IATE, CIRAD, Montpellier, France

Lipid oxidation is a major issue in foods containing LC PUFA. Lipid oxidation can be inhibited or reduced by the addition of antioxidants. Many food products are emulsions. According to the "polar paradox" hypothesis, polar compounds are more efficient as antioxidants in bulk oil, whereas lipophilic compounds are more efficient antioxidants in emulsions. Lately, extensive work has been performed on phenolipids and their antioxidant efficacy in emulsions. It was found that the "polar paradox" hypothesis was too simple to explain the observed efficacy of the phenolipids. The antioxidant efficacy increased with increasing length of the alkyl chain up to a certain length after which the efficacy decreased. Therefore, a new term, "cut-off effect", was introduced to describe this behavior. Furthermore, the length of the alkyl chain for optimal antioxidant effect has been shown to be influenced by the type of emulsions.

The aim of this study was to evaluate the antioxidative effect of caffeic acid and its esters C1 – C20, caffeates, in two different emulsion systems. In the first system we used stripped fish-rapeseed oil (50:50) and for the second system we used non-stripped fish-rapeseed oil (50:50) and for both systems Tween80 was used as emulsifier. Hence, the first system was without tocopherol and the second system was with tocopherols from the oil. In addition, caffeates were evaluated as antioxidants in two fish oil enriched food products: milk and mayonnaise. Lipid oxidation was evaluated from three parameters measured over time: peroxide value (PV), secondary volatile oxidation products and tocopherol concentrations. The results demonstrate the efficacy of caffeates in simple emulsions and food emulsions. Furthermore, the two different simple emulsion systems reveal possible interactions between caffeates and tocopherols.

Sesamol as a natural antioxidant for frying oil

Hong-Sik Hwang, hongsik.hwang@ars.usda.gov, Jill K Winkler-Moser, Erica L Bakota, Mark A Berhow, Sean X Liu. USDA, ARS, NCAUR, Peoria, IL 61604, United States

Sesamol is relatively inexpensive and well-documented to have strong antioxidant activity and health benefits. However, it is not being used in the food industry for frying oil yet. In this study, to demonstrate the practical use of sesamol as antioxidant, it was tested in a miniaturized frying device where pieces of potato were fried with small-scale frying equipment and compared with TBHQ, a synthetic antioxidant. Oxidation of soybean oil was determined by gel permeation chromatography for polymerized triacylglycerols and by 1H NMR spectroscopy for reactions at reactive sites of soybean oil molecules including olefinic, bisallylic and allylic protons during frying. An HPLC experiment showed that the concentration of sesamol decreased sharply during frying. Thermogravimetric analysis (TGA) indicated that sesamol is highly volatile and easily oxidizes when exposed to air. To overcome this problem, two multiple addition methods were evaluated in which sesamol was added portion by portion every hour. The multiple additions of divided portions of 0.66% (w/w) sesamol maintained the concentration of sesamol at the minimum of 0.04-0.06% throughout the frying process and showed improved antioxidant activity compared to one single addition of 0.66% sesamol at the beginning of frying. One of the multiple addition methods showed 28, 18, 59, and 27% less polymerized triacylglycerols and losses of olefinic, bisallylic and allylic protons, respectively, than 0.020% TBHQ after 8-hr frying. This study shows that sesamol can be used as an alternative for synthetic antioxidants for frying oil.

Application of phenolic compounds to control reactive carbonyl species and off-flavor development in aseptic milk

Smaro Kokkinidou, kokk0013@umn.edu, Devin Peterson. Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, United States

The Maillard reaction (MR) is well known to impact the quality of food (i.e. flavor, color, therapeutic and toxic compounds). In biology, Maillard derived reactive carbonyl species (RCSs), have been associated with several pathological conditions. Consequently the ability to control the pathways/products of this reaction would be beneficial to the food and pharmaceutical industry. The goal of this study was to provide a more in-depth understanding of phenolic structure-reactivity on controlling the pathways of the MR, specifically in aseptically processed milk during both thermal processing and storage. Phenolic compounds with a more activated ring structure for aromatic electrophilic substitution reactions were more reactive at suppressing the MR. Response surface methodology (RSM) was utilized to investigate the dose-response relationships of a phenolic mixture (catechin, genistein and daidzein) on RCS and off-flavor generation. Canonical analysis indicated catechin to be the most influential factor for the reduction of RCSs but unique reactivity and interactions between phenolic compounds were observed. Overall RSM provided a basis to understand phenolic structure reactivity and to optimize the composition of a tertiary mixture of phenolic compounds for the reduction of RCSs and off-flavor development in aseptic milk.

Polyphenols -- the key to coffee taste

Oliver Frank, oliver.frank@tum.de, Stefanie Kreppenhofer, Thomas Hofmann. Food Chemistry, Technical University of Munich, Freising, Bavaria 85354, Germany

Freshly brewed coffee is appreciated by consumers all over the world because of its stimulating effect, its attractive aroma, and its characteristic taste centering on bitterness and sourness. Although multiple molecules have been identified as coffee components, neither their human bitter detection thresholds have been determined, nor any evaluation of their sensory significance for coffee quality has been done so far. In particular, the structures of sensorially active non-volatiles which are not present in coffee per se, but are generated during bean roasting remain mainly unknown. In summary, the key compounds contributing to coffee bitterness are still not defined on a molecular level.

In order to bridge the gap between pure structural chemistry and human taste perception and to rate the coffee components according to their relative impact on the bitter taste of coffee beverage, various techniques of molecular sensory science were applied on roasted coffee as well as on thermally processed model precursor mixtures. This screening for non-volatile taste compounds, followed by chromatographic purification, LC/MS and NMR spectroscopic as well as synthetic studies led to the unequivocal identification of eleven caffeoyl- and feruloylquinic acid lactones, and nine vinylcatechol dimers and trimers as well as ten (furan-2-yl)methylated benzene diols and triols as previously not reported bitter molecules in coffee. Differing from the pleasant bitter quality of the caffeoylquinic acid lactones and, depending on their chemical structure, these vinylcatechol oligomers exhibited an intense harsh bitter taste quality with human threshold concentrations between 0.023 and 0.178 mmol/kg (water). In addition, the (furan-2-yl)methylated benzene diols and triols were described with an astringent mouthfeel as well as a clear bitter taste. Depending on their chemical structure, the recognition thresholds ranged between 16 and 900 µmol/L for astringency and between 100 and 1800 µmol/L for bitter taste.

Anti-inflammatory properties of urolithins A and B in macrophages

Woo Young Bang, wybang@neo.tamu.edu, Elisa Schreckinger, Luis Cisneros-Zevallos. Horticultural Sciences, Texas A&M University, College Station, Texas 77843, United States

We selected two metabolites of ellagic acid, urolithins A and B, to perform anti-inflammatory bioassays with macrophages challenged with LPS. Both, urolithins A and B, are metabolized by gut microflora from hydrolizable tannins as those present in pecans. Results indicated that reactive oxygen species (ROS) are reduced in an early stage (3 h) by urolithin A and in a late stage (24 h) by both urolithins A and B, while ellagic acid showed no effect. Furthermore, urolithin A showed a reduction in NO production and levels of TNF-a, IL 1-b and prostaglandin PGE2. Urolithin B showed similar trend on those same markers but did not affect NO production. In general, ellagic acid did not show an anti-inflammatory effect in macrophages. We used DPI to reduce ROS production by NADPH oxidase and the corresponding effects in inflammatory markers. Discussion of mode of action by which urolithins A and B exert their anti-inflammatory properties will be based on antioxidant (AOX) and AOX-independent mechanisms.

Processed strawberry puree improved color and anthocyanin stability by oxygen exclusion

Luke R. Howard, lukeh@uark.edu, Cindi Brownmiller, Ronald L. Prior. Department of Food Science, University of Arkansas, Fayetteville, AR 72704, United States

Strawberries are prone to browning and anthocyanin losses during processing and long-term storage at ambient temperature, which in part may due to a heat stable polyphenol oxidase. Nitrogen or carbon dioxide atmosphere may prevent enzymatic degradation of processed berries leading to improved color and anthocyanin stability. In this study we processed strawberries into puree under air and in a glove box under nitrogen or carbon dioxide atmosphere. Samples were analyzed before and after pasteurization, and after 2, 4, 6, and 8 weeks of storage at 25oC for color, anthocyanins, and percent polymeric color. Strawberries processed under nitrogen or carbon dioxide had higher total anthocyanin and chroma values, and lower hue angle and percent polymeric color values than samples processed under air. These findings demonstrate that oxygen exclusion results in a product with a more vivid red color and higher levels of health-promoting anthocyanins.

Kinetics of spray-dried anthocyanin release under different storage conditions

Coralia Osorio, cosorior@unal.edu.co, Departamento de Quimica, Universidad Nacional de Colombia, Bogota, Colombia

Anthocyanins are a major subclass of flavonoid compounds existing widely in flowers, fruits, and vegetables. Additional to their contribution in pigmentation, they have been receiving considerable attention due to their wide range of biological activities, such as antioxidant, anti-inflammatory, and anticarcinogenic, among others. With the aim to get natural red colorants for food applications, four anthocyanin-rich extracts (AREs) were obtained from different sources, corozo (Bactris guineensis), uva caimarona (Pourouma cecropiifolia), Andes berry (Rubus glaucus Benth.), and tamarillo (Solanum betaceum Cav., red variety). These aqueous extracts were separately transformed in solids by spray-drying process using maltodextrin as encapsulating agent. Their stability was evaluated at controlled temperature and humidity and in the absence of light. The independent variables considered were the humidity (75 and 95%), temperature (4, 18, 50, and 70 °C), and time of storage. The dependent variable was the anthocyanin content, determined by pH-differential method on solutions of 1 g of solid/1.5mL of water. Results showed that temperature and humidity are key factors in anthocyanin's release during storage. In all of the cases, it was probed that this degradation follows a pseudo-first-order kinetics, showing that higher temperature increase the rate constant value of this reaction. Differences in stability among fruits are attributable to molecules acting as copigments that are present in microencapsulates. Thus, the use of spray-drying technique is an alternative to extent the shelf-life time of anthocyanins to be used in food industry.

Profiling bourbons and American whiskeys using UHPLC/QTOF-MS

Thomas S Collins1, tscollins@ucdavis.edu, Jerry Zweigenbaum2, Susan E Ebeler1. (1) Department of Viticulture and Enology, U.C. Davis, Davis, CA 95616, United States, (2) Agilent Technologies, Wilmington, DE 19808, United States

While the aroma and flavor of newly distilled whiskeys can be related to the volatile composition of the spirit, straight bourbon whiskeys must be aged in new charred American oak casks for two years or longer. During this period, polyphenols and other non-volatile compounds are extracted from the casks, resulting in changes in the color, flavor and mouth-feel of the spirit. This study evaluates the non-volatile profiles of bourbons and other American whiskeys to differentiate among straight bourbon whiskeys, rye whiskeys and other American whiskeys. Sixty whiskeys were selected for this study, including 38 straight bourbon whiskeys, 10 rye whiskeys, five Tennessee whiskeys and seven other American whiskeys. The whiskeys varied in age from two to fifteen years. Analysis was performed on an Agilent 1290 UHPLC/6430 QTOF-MS system. Separation was accomplished on a 2.1 mm i.d. 5 cm x 1.8 µm Zorbax Eclipse plus C18 column using an acetic acid/methanol-acetic acid gradient. The QTOF-MS was run in negative mode with an m/z range of 100-3200. Data analysis was conducted using the Agilent MassHunter and Mass Profiler Professional software. The data was mined for compounds using a molecular feature extractor, filtered and statistically compared to find distinguishing components for each whiskey type. Multivariate analysis of accurate masses and retention times was used to discriminate among the whiskeys. Bourbons were readily differentiated from Tennessee and other American whiskeys, but were not well separated from rye whiskeys, many of which were produced at distilleries which also make bourbon whiskeys. Compounds identified as important to the ability to differentiate among the whiskeys included oak related polyphenols, fatty acids and alcohols and flavonoid glycosides. This study demonstrates the ability to differentiate among several similar whiskey types using UHPLC/QTOF-MS.

Interactions of anthocyanins with magnesium ions

Henry D Schreiber, HS@vmi.edu, Corinne M Lariviere, Ruthann P Hodges. Department of Chemistry, Virginia Military Institute, Lexington, VA 24450, United States

Anthocyanins typically exist as the red flavylium cation in acidic solutions and as the blue quinoidal base anion in basic solutions. However, the quinoidal base anion for delphinidin-, cyanidin-, and petunidin-based anthocyanins can also be stabilized in acidic solutions by complexation with a molar excess of aluminum ions. This complexation occurs naturally in the bluing of the delphindin-3-glucoside pigment in hydrangea sepals. The stabilization of the quinoidal base anion (or bluing) of various anthocyanins by magnesium ions was investigated as a function of magnesium ion concentration and pH in a model solvent system of acidic ethanol. As expected in this solvent, magnesium ions were a much weaker complexing agent for bluing than aluminum ions. For aluminum ions as the complexing agent, the bluing mechanism consists of two components; the aluminum ion anchors the complex and coordinates to the blue quinoidal base anion, and simultaneously a flavylium cation stacks onto the anion and enhances the bluing. The magnesium complex possesses some similarities to this aluminum complex with anthocyanins, although some subtle differences exist in the nature of the bluing. In situ application of a large molar excess of magnesium ions onto red hydrangea sepals does not result in bluing, but onto blue hydrangea sepals unexpectedly generates distinct red, white, and blue bands of coloration on the sepals.

Polyphenolic compounds for the management of inflammatory diseases

Chi-Tang Ho, ho@aesop.rutgers.edu, Min-Hsiung Pan. Department of Seafood Science, National Kaohsiung Marine University, Kaohsiung, Taiwan Republic of China

Over the past few decades, inflammation has been recognized as a major risk factor for various human diseases. Acute inflammation is short-term, self-limiting and it's easy for host defenses to return the body to homeostasis. Chronic inflammatory responses are predispose to a pathological progression of chronic illnesses characterized by infiltration of inflammatory cells, excessive production of cytokines, dysregulation of cellular signaling and loss of barrier function. Targeting reduction of chronic inflammation is a beneficial strategy to combat several human diseases. Plant phenolic compounds presented in the average diet in such foods as fruits and vegetables have been demonstrated to exhibit a broad spectrum of biological activities for human health including an anti-inflammatory property. These natural bioactive compounds exert anti-inflammatory activity by modulating pro-inflammatory gene expressions have shown promising chemopreventive activity. We will discuss our recent research on the anti-inflammatory activities of hydroxypolymethoxyflavones, theaflavins, stilbene derivatives and shogaols. Although presence of polyphenols in foods is important, their absorption, bioavailability and metabolism are also critical factors that influence in their beneficial effects.

Pterostilbene demonstrates antianxiety effect in animal model

Agnes M Rimando1, agnes.rimando@ars.usda.gov, Md. Al Rahim2, Kalpten Silistreli3, Abir T El-Alfy4. (1) Agricultural Reserach Service, U.S. Department of Agriculture, University, MS 38677, United States, (2) Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States, (3) Turkey Ministry of Health, Ankara, Turkey, (4) Department of Pharmaceutical Sciences, Chicago State University College of Pharmacy, Chicago, IL 60628, United States

Pterostilbene has been previously shown to be effective in reversing cognitive behavioral deficits and as a potent modulator of cognition in animal models. These results triggered our investigation of other neurological effects of pterostilbene, and thus explored its anxiolytic activity. In the present study, pterostilbene was administered to mice by oral gavage at 1, 2, 5, and 10 mg/kg BW and the mice were subjected to the elevated-plus maze (EPM) test. Anxiolytic activity was observed at 1 and 2 mg/kg doses, demonstrated by increased percent permanence time and number of entries in open arms, which are critical determinants for anxiety. This activity was comparable to that of diazepam at 1 and 2 mg/kg. At the 5 and 10 mg/kg doses the anxiolytic effect was not manifested. Pterostilbene was quantified in the serum and hippocampus following a single oral administration. Western blot analysis corroborated the EPM observations and revealed a decrease in both ERK1 and ERK2 phosphorylation in hippocampal homogenates from mice treated with 1 and 2 mg/kg pterostilbene, suggesting that downregulation of ERK phosphorylation might be a downstream mediator of pterostilbene anxiolytic action. The locomotor activity of the animals was unaffected at all doses. Our results indicate that pterostilbene is a natural compound that has the potential to alleviate anxiety disorders.

Black tea theaflavins extract extends the lifespan of fruit flies

Zhen-Yu Chen, zhenyuchen@cuhk.edu.hk, Cheng Peng, Yuk Man Li. Food and Nutritional Sciences Programme, School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China

Black tea theaflavins extract (BTE) is rich in antioxidants namely epicatechins and theaflavins. Dietary antioxidants have become popular supplements in prevention of ageing. The present study was to investigate whether BTE could extend the lifespan of Drosophila melanogaster. Results showed the mean lifespan was significantly extended from 51 to 56 days when the fruit flies were given 10 mg/ml BTE. Gene expression of superoxide dismutase (SOD1 and SOD2), catalase (CAT) and methuselah (MTH) was characterized by an increase in young and then a decrease in aged fruit flies. Higher gene expression of SOD1 and CAT was observed in the BTE-treated group than the control flies. However, BTE exerted a minimal effect on the expression of SOD2 and MTH genes. Dietary fat could induce oxidative stress and shorten the maximum lifespan to 15 days, while addition of 10 mg/mL BTE into diet extended it to 28 days. Paraquat and H2O2 challenge tests demonstrated that BTE prolonged the survival time only for Oregon R wild type flies but not for SODn108 or Catn1 mutants. This suggests that the lifespan-prolonging activity of BTE is mediated at least in part through SOD and CAT.

Novel insight on the high oxidative stability of roasted mustard seed oil

Kshitij Shrestha, Kshitij.Shrestha@UGent.be, Feyera Gobena Gemechu, Bruno De Meulenaer, Bruno.DeMeulenaer@UGent.be. Department of Food Safety and Food Quality, NutriFOODchem Unit, Ghent University, Ghent, Non-US/Canada 9000, Belgium

This study was carried out to explore the possible mechanisms behind the high oxidative stability of roasted mustard seed oil. A potent radical scavenger formed during mustard seed roasting was isolated and identified based on nuclear magnetic resonance, mass spectrometry, ultraviolet and fluorescence spectra. The compound was found to be 2,6-dimethoxy-4-vinylphenol (canolol) and was confirmed by chemical synthesis. The oxidative stability of the sixteen different crude roasted mustard seed oil samples collected from the Nepalese market was evaluated by monitoring the peroxide value (PV) and conjugated diene (CD) during storage at 50 oC (in dark). These samples showed a wide variability in the oxidative stability. Some of the samples were shown to be highly stable even after 69 days of storage reaching PV less than 9 meq oxygen/kg fat. The oxidative stability of the different samples (PV after 40 days of storage (PV40) as an index) was not significantly correlated (p > 0.05) with both the sum of the tocopherols and canolol content of the oil and the total radical scavenging activity of the oil using the DPPH assay. On the other hand, the PV40 was negatively correlated with the absorbance at 350 nm (p < 0.001), fluorescence (excitation at 350 nm and emission at 440 nm) (p < 0.001), phospholipid content (p < 0.001), pyrrolized phospholipid content (p < 0.01) and canolol content (p < 0.01). Moreover, phospholipid content, fluorescence, pyrrolized phospholipid content and absorbance at 350 nm were highly positively correlated (p < 0.001) with each other. The phospholipids and its Maillard type browning reaction products together with canolol were primarily responsible for the high oxidative stability of the roasted mustard seed oil samples.

Anti-inflammatory properties of Acerola leaf and fruit (Malpighia emarginata) polyphenolic fractions in macrophages

Woo Young Bang1, Elisa Schreckinger1, schreckinger@gmail.com, Ricardo Elesbao Alves2, Luis Cisneros-Zevallos1. (1) Texas A&M University, College Station, Texas 77843, United States, (2) EMBRAPA, Fortaleza, Brazil

We report on the anti-inflammatory properties of polyphenolic fractions from Acerola leaf, ripe and green mature fruit. Result show evidence that acerola leaf extracts and fractions exert anti-inflammatory properties in macrophage cells. Furthermore, extracts of green and ripe fruit also possess anti-inflammatory properties. However, while leaf extracts and fractions seem to have dual mode of action by scavenging ROS and inhibiting COX-2 activity, it is likely that both fruit extracts exert their anti-inflammatory properties only by the latter mechanism.

The bioactive principle may reside in the polyphenolic compounds and not necessarily in the vitamin C content of the extracts. Acerola are known to be one of the fruits with highest vitamin content in nature. Further work on gene and protein expression as well as enzyme activities will be discussed within the hypothesis frame. In addition, full characterization of the phenolic profiles will be presented and discussed to give insight of the identity of the active polyphenols with anti-inflammatory properties present in the extracts and fractions.

Anthocyanin structure-function relationships and their impact on cancer cells

Pu Jing1, pjcolumbus@gmail.com, Maria Monica Giusti2. (1) Department of Food Science and Engineering, Shanghai Jiao Tong University, Shanghai, China 200240, China, (2) Department of Food Science and Technology, The Ohio State University, Columbus, Ohio 43210, United States

Our group has been studying the chemoprotective effects of flavonoids for many years. This presentation will present an overview of our research on anthocyanin biological activity. By screening a variety of edible anthocyanin sources for chemopreventive activity, we found that anthocyanin-rich extract from plant materials with different and distinctive anthocyanin profiles currently used or potential food natural colorants including chokeberry, elderberry, bilberry, grape, purple carrot, purple corn, red radish, and eggplant exhibited colon cancer cell chemoprotective activity. Those anthocyanins showed an additive effect between anthocyanins with other phenolics from the same plant sources as chemoprotective agents.

A comprehensive statistical comparison of anthocyanins with various structure patterns demonstrated that glycosylation and acylation pattern have important impact on their biological activity in a HT-29 cell model.

Computer simulation was used to predict the bioactivity of anthocyanin or their conjugated phenolic acids based on their structure properties. A 3D-QSAR model was established to predict anthocyanins/phenolic acids with high radical scavenging activity to understand their structure-activity relationships. With aid of contour maps, the structural characteristics of anthocyanins/ phenolics acids favorable for high radical scavenging activity have been elucidated.

Pure anthocyanins typically present in fruits and vegetables have been tested for their ability to inhibit gastrointestinal (GI) tumor cell growth including human mouth epidermal carcinoma (KB), esophageal adenocarcinoma cells (TE-1), and colorectal adenocarcinoma cells (HT-29 and HCT-116), and their antioxidant capacity. We found anthocyanins exhibited selective chemopreventive action on the four GI tract cell lines and worked potent radical scavengers ex vivo via increasing of GSR expression and protecting DNA damage.

Our data, combined with data from other laboratories, compiles strong evidence of the GI chemoprotective effects of anthocyanins, and they deserve close attention for in vivo systems. Incorporation of anthocyanins into the diet could be facilitated through their use as food colorants.

Dietary polyphenols and human gut microbiota

Francisco A Tomas-Barberan, fatomas@cebas.csic.es, Department of Food Science, CEBAS-CSIC, Murcia, Spain

Polyphenols present in the diet and their health effects have been the objective of active research over the last 20 years. The current evidence shows that the absorption of these phytochemicals in the gut is limited and they reach the colon almost unaltered where they meet the colon microbiota. The colon microbiome has a two-way relationship with polyphenols, as these food constituents in one hand modulate the microbiota population, and on the other hand the microbiota transforms polyphenols producing metabolites that differ from the original dietary constituents. Dietary polyphenols activate the development of some bacterial groups (particularly probiotics such as lactobacillus and bifidobacteria) while inhibit the growth of other bacterial groups (enterobacteria, bacteroides, etc.). This is associated with gut health benefits. Colonic microbiome can metabolize polyphenols leading to compounds that have better bioavailability than the original compounds or have improved health effects. This often extends the biological effects of the original polyphenols. Therefore, depending on the composition of the gut microbiome, polyphenols can be metabolized to more bioavailable metabolites or with improved biological effects. The identification of the bacteria responsible for the metabolic transformation of specific phenolics is an active area of research. Bacterial species able to convert ellagic acid, isoflavones, resveratrol, lignans, flavonoids have been discovered. The study of the mechanisms through which these metabolites exert their biological effects is an active field of research. This means that individuals can produce, absorb and excrete different polyphenol metabolites, and enjoy different biological effects due to polyphenols intake, depending on their microbiome. This opens new opportunities for the development of drugs, nutraceuticals and functional foods. The recent discovery of the human enterotypes will eventually have future implications in the nutritional and medicinal plants treatments and in the development of specific drugs and food products for individuals with a specific enterotype.

Modulation of adipogenesis and inflammation in adipocytes by ellagic acid and metabolites urolithins A and B

Luis Cisneros-Zevallos, lcisnero@ag.tamu.edu, Woo Young Bang. Texas A&M University, College Station, Texas 77843, United States

We tested the effects of ellagic acid, urolithins A and B on pre-adipocyte differentiation, adipogenesis and inflammation in fat cells. Results indicated that ellagic acid and urolithin A inhibit adipogenesis (fat accumulation) but not differentiation. Urolithin B did not show that same effect. Modulation of fat accumulation seems to be through gene regulation of Glut 4. We tested the effects of ellagic acid, urolithins A and B on adipocytes challenged with lipopolysaccharide (LPS) to trigger inflammation. Results indicated that urolithins A and B reduce levels of nuclear phosphorilated NFkB. Gene expression of cytokines and proteins associated to the inflammation process indicate that urolithin A inhibit TNFα and iNOS, urolithin B inhibits only iNOS and ellagic acid inhibits TNFα, IL-6, iNOS and MCP-1. None of these compounds inhibited the gene expression of COX-2. The mode of action by which ellagic acid and urolithins A and B exert their anti-inflammatory properties will be discussed based on antioxidant (AOX) and AOX-independent mechanisms.

Lipophilic polyphenols and their activities

Fereidoon Shahidi, fshahidi@mun.ca, Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada

Polyphenols are secondary plant metabolites that possess a number of biological activities in plans and serve as potent antioxidants in foods to protect them from deleterious effects of oxidation and their production is enhanced under stress conditions. Some polyphenols such as catechins in green tea are hydrophilic and hence they are not readily applicable to lipophilic foods and may also not be easily absorbed by the body. Esterification of epigallocatechin gallate (EGCG) and epigallocatechin (EGC), the dominant polyphenols of green tea was carried out using saturated, monounsaturated and polyunsaturated fatty acids. The products so obtained had improved and unique properties. Insertion of phenolic acids into marine oils as well as sterols also rendered products that had improved oxidative stability. The presentation provides details about the compounds so produced and their potential use as food, supplement and medicinal ingredients.



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