Tannin-protein complexes as radical scavengers and radical sinks

Hydrophobized plant polyphenols: self-assembly and promising antibacterial, adhesive, and anticorrosion coatings

A naturally abundant plant polyphenol was rationally modified to partiallyn-alkylated derivatives for wide-range organosolubility, spontaneous fibrous self-assembly, and a highly stable multifunctional thin-film.

Step-by-step deposition of type B gelatin and tannic acid displays a peculiar ionic strength dependence at pH 5

Tannic acid (TA), among other polyphenols, interacts strongly with proteins, in particular proline rich proteins, a mechanism which is at the origin of mouth astringency.

Hydrogen-bonded multilayers of tannic acid as mediators of T-cell immunity

Type 1 diabetes is an autoimmune-mediated disease resulting in the destruction of insulin-secreting pancreatic β-cells. Transplantation of insulin-producing islets is a viable treatment to restore euglycemia in Type 1 diabetics; however, the clinical application remains limited due to the use of toxic immunosuppressive therapies to prevent immune-mediated rejection. A nanothin polymer material with dual antioxidant and immunosuppressive properties capable of modulating both innate and adaptive immune responses crucial for transplantation outcome is presented. Through the use of hollow microparticles (capsules) composed of hydrogen-bonded multilayers of natural polyphenol (tannic acid) with poly(N-vinylpyrrolidone) (TA/PVPON) and with poly(N-vinylcaprolactam) (TA/PVCL), proinflammatory reactive oxygen and nitrogen species are efficiently dissipated and the production of interferon (IFN)-γ and tumor necrosis factor (TNF)-α proinflammatory cytokines is attenuated by cognate antigen-stimulated autoreactive CD4+ T cells. These results provide evidence that TA-containing capsules are efficacious in immunomodulation and may provide physical transplant protection and prevent diabetogenic autoreactive T-cell responses. Future studies will determine if xeno- and allotransplantation with (TA/PVPON)- or (TA/PVCL)-coated pancreatic islets will decrease the risk of graft rejection due to attenuation of oxidative stress and IFN-γ, and restore euglycemia in Type 1 diabetics.

Effect of (-)-epigallocatechin-3-gallate on glucose-induced human serum albumin glycation

(-)-Epigallocatechin-3-gallate (EGCg) is a naturally occurring polyphenol found in plant-based foods and beverages such as green tea. Although EGCg can eliminate carbonyl species produced by glucose autoxidation and thus can inhibit protein glycation, it is also reported to be a pro-oxidant that stimulates protein glycation in vitro. To better understand the balance between antioxidant and pro-oxidant features of EGCg, we evaluated EGCg-mediated bioactivities in a human serum albumin (HSA)/glucose model by varying three different parameters (glucose level, EGCg concentration, and time of exposure to EGCg). Measurements of glycation-induced fluorescence, protein carbonyls, and electrophoretic mobility showed that the level of HSA glycation was positively related to the glucose level over the range 10-100 mM during a 21-day incubation at 37°C and pH: 7.4. Under mild glycemic pressure (10 mM), long exposure to EGCg enhanced HSA glycation, while brief exposure to low concentrations of EGCg did not. Under high glycemic pressure (100 mM glucose), long exposure to EGCg inhibited glycation. For the first time we showed that brief exposure to EGCg reversed glycation-induced fluorescence, indicating a restorative effect. In conclusion, our research identified glucose level, EGCg concentration, and time of exposure as critical factors dictating EGCg bioactivities in HSA glycation. EGCg did not affect HSA glycation under normal physiological conditions but had a potential therapeutic effect on HSA severely damaged by glycation.

Compartmentalized accumulation of cAMP near complexes of multidrug resistance protein 4 (MRP4) and cystic fibrosis transmembrane conductance regulator (CFTR) contributes to drug-induced diarrhea

Diarrhea is one of the most common adverse side effects observed in ∼7% of individuals consuming Food and Drug Administration (FDA)-approved drugs. The mechanism of how these drugs alter fluid secretion in the gut and induce diarrhea is not clearly understood. Several drugs are either substrates or inhibitors of multidrug resistance protein 4 (MRP4), such as the anti-colon cancer drug irinotecan and an anti-retroviral used to treat HIV infection, 3'-azido-3'-deoxythymidine (AZT). These drugs activate cystic fibrosis transmembrane conductance regulator (CFTR)-mediated fluid secretion by inhibiting MRP4-mediated cAMP efflux. Binding of drugs to MRP4 augments the formation of MRP4-CFTR-containing macromolecular complexes that is mediated via scaffolding protein PDZK1. Importantly, HIV patients on AZT treatment demonstrate augmented MRP4-CFTR complex formation in the colon, which defines a novel paradigm of drug-induced diarrhea.

Stability and quality of herb (Pueraria Tuberosa)-milk model system

The medicinal benefits of herbs could be conveyed via certain foods as carriers. Milk is one of the important carrier which has been effectively used to deliver phytochemicals presents in herbs (mainly polyphenols) for targeted health benefits in the traditional Indian system of medical science. The present study was conducted to evaluate the effect of herb components (Pueraria tuberosa) on properties of Pueraria tuberosa-milk model system. The herb was added into cow milk on the basis of sensory evaluation (0.4 %) by using 9-point hedonic scale. The physical and chemical changes were evaluated after various processing treatments viz. pasteurization (72 °C, 15 s), sterilization (121 °C, 15 min), separation etc. These changes were determined using viscosity, hydroxy methyl furfural (HMF) value, ethanol stability, colour characteristics and trolox equivalent antioxidant capacity (TEAC). It was observed that addition of Pueraria tuberosa to milk resulted in decreased HMF content, ethanol stability and lightness whereas antioxidant activity, redness and yellowness increased as compared to control. It can be concluded that addition of Pueraria tuberosa to milk at 0.4 % concentration altered the functional properties of milk and Pueraira tuberosa could be suitable for preparation of low heat treated functional dairy food products.

Interaction of Sorghum Tannins with Wheat Proteins and Effect on in Vitro Starch and Protein Digestibility in a Baked Product Matrix

Carbohydrates contribute the most dietary calories, which makes starchy foods a logical target for modifying calorie intake. This study investigated the interaction of sorghum bran proanthocyanidins (PA) with proteins during wheat flour tortilla processing and impact on in vitro starch digestibility. Brans from wheat, white (low in phenols), brown (high PA), and black (high monomeric flavonoids) sorghum were used. Changes in phenolic profile, starch, and proteins were evaluated. Dough mixing drastically decreased extractable PA (61-72%) but not monomeric phenolics; higher MW PA decreased the most. The high PA bran dough produced the highest insoluble proteins (460 vs 330 mg/g protein for other sorghum brans) at 25% baker's substitution. The high PA bran tortillas also had higher slow digesting starch and lower rapidly digesting starch than all other bran treatments. Significant sorghum PA-gluten interactions occur during dough mixing that may slow starch digestibility in the baked products.

Evaluation of the interactions between rosmarinic acid and bovine milk casein

Non-covalent interactions occur between rosmarinic acid and caseins.

Effects of Sulla forage (Sulla coronarium L.) on the oxidative status and milk polyphenol content in goats

Twelve milking Girgentana goats were allocated into 3 groups and fed 3 diets ad libitum in a 3×3 Latin square design with 3 periods. The diets were Sulla fresh forage ad libitum (SUL), Sulla fresh forage ad libitum and 800g/d of barley meal (SULB), and mixed hay ad libitum and 800g/d of barley meal (HB). Changes were observed in total polyphenol intake, plasma oxidative status, plasma polyphenol content, metabolic status, milk polyphenol content, and total antioxidant capacity. The fresh forage diets (SUL and SULB) increased dry matter, total polyphenol, nontannic polyphenol and tannin intakes, and the milk total protein, casein, milk total polyphenols, and milk free polyphenols compared with the HB diet. The intake of condensed tannins was higher in the SUL than in the HB group, and an intermediate value was recorded for the SULB group. Plasma from the SUL- and SULB-fed goats exhibited greater total antioxidant capacity and greater total polyphenol and free polyphenol levels compared with the plasma from the HB group. Positive correlations between plasma total antioxidant capacity and condensed tannins intake (r=0.43), plasma total polyphenol and total polyphenol intake (r=0.61), and plasma free polyphenol and milk total polyphenols (r=0.38) were observed. The correlation between milk free polyphenols and whey total antioxidant capacity (r=0.42) highlights the role of free polyphenols in the determination of the antioxidant activity of milk. These results indicate that Sulla fresh forage exerts an antioxidant activity due to its secondary compounds that provide additional antioxidant value and that Sulla forage appears to be a promising strategy for improving product quality.

Nature and consequences of non-covalent interactions between flavonoids and macronutrients in foods

Many of the potential health benefits of flavonoids have been associated with their specific chemical and biological properties including their ability to interact and bind non-covalently to macronutrients in foods. While flavonoid-protein interactions and binding have been the subject of intensive study, significantly less is understood about non-covalent interactions with carbohydrates and lipids. These interactions with macronutrients are likely to impact both the flavonoid properties in foods, such as their radical scavenging activity, and the food or beverage matrix itself, including their taste, texture and other sensorial properties. Overall, non-covalent binding of flavonoids with macronutrients is primarily driven by van der Waals interactions. From the flavonoid perspective, these interactions are modulated by characteristics such as degree of polymerization, molecular flexibility, number of external hydroxyl groups, or number of terminal galloyl groups. From the macronutrient standpoint, electrostatic and ionic interactions are generally predominant with carbohydrates, while hydrophobic interactions are generally predominant with lipids and mainly limited to interactions with flavonols. All of these interactions are involved in flavonoid-protein interactions. While primarily associated with undesirable characteristics in foods and beverages, such as astringency, negative impact on macronutrient digestibility and hazing, more recent efforts have attempted to leverage these interactions to develop controlled delivery systems or strategies to enhance flavonoids bioavailability. This paper aims at reviewing the fundamental bases for non-covalent interactions, their occurrence in food and beverage systems and their impact on the physico-chemical, organoleptic and some nutritional properties of food.

Protein-phenolic interaction of tryptic digests of β-lactoglobulin and cloudberry ellagitannin

LC-ESI-MS was applied to investigate interaction reactions between a dimeric ellagitannin, sanguiin H-6, isolated from cloudberries (Rubus chamaemorus) and peptides of β-lactoglobulin (β-Lg). Three peptides, LIVTQTMK (m/z 934), ALPMHIR (m/z 838), and IPAVFK (m/z 674) were isolated from enzymatic (trypsin) digestion of β-Lg. Oxidation of the peptides with and without sanguiin H-6 was monitored by LC-ESI-MS for up to 7 days. Sanguiin H-6 showed radical scavenging activities toward oxidation of the selected peptides. An interaction product was found with sanguiin H-6 and peptide LIVTQTMK by using MS and supported by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). An observable (haze) but unstable interaction product of sanguiin H-6 was seen with peptide ALPMHIR, but no detectable interaction products were seen with peptide IPAVFK. A higher proportion of sanguiin H-6 toward the amount of peptide might allow for further characterization of these interaction products.

One- and two-dimensional high-performance thin-layer chromatography as an alternative analytical tool for investigating polyphenol-protein interactions

INTRODUCTION

Polyphenols and simple phenolic compounds are able to react with other food constituents during processing and storage. In the past, it has been shown that their reaction with proteins can lead to changes of the technofunctional or even physiological properties of both compound classes. However, identification of specific binding sites of small molecules within a protein sequence (and the corresponding conformational position) is still challenging.

OBJECTIVE

Investigating the reaction between different food proteins and phenolic compounds in alkaline medium with one- and two-dimensional high-performance thin-layer chromatography (HPTLC) coupled to matrix-assisted laser desorption/ionisation (MALDI) with time-of-flight (TOF) MS for analysing the peptide profiles after tryptic digestion.

METHODS

After modification with phenolic compounds, protein derivatives were digested and peptides were separated with one- and two-dimensional HPTLC. Peptide profiles were detected with visible and UV wavelengths as well as with fluorescamine, ninhydrin and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid staining. In order to perform mass spectrometric measurements, peptides separated in the first dimension were analysed by MALDI/TOF/MS.

RESULTS

Results show that the phenolic acids applied in this study show different specificity and susceptibility when modifying proteins resulting in changes of the peptide profiles, peptide quantity, polarity, UV-activity, radical-scavenging activity and molecular mass.

CONCLUSION

One- and two-dimensional HPTLC supported by mass spectrometric detection represents an innovative, alternative tool for investigating and understanding polyphenol-protein interactions. This approach enables the identification of binding sites inside the protein chain and contributes to understanding the mechanism of polyphenol-protein interactions in vitro and in vivo.

Investigation of Diospyros Kaki L.f husk extracts as corrosion inhibitors and bactericide in oil field

Background

Hydrochloric acid is used in oil-well acidizing commonly for improving the crude oil production of the low-permeable reservoirs, while it is a great challenge for the metal instruments involved in the acidification. Developing natural products as oilfield chemicals is a straight way to find less expensive, green and eco-friendly materials. The great plant resources in Qin-ling and Ba-shan Mountain Area of Shannxi Province enable the investigating of new green oil field chemicals. Diospyros Kaki L.f (persimmon), a famous fruit tree is widely planted in Qin-ling and Ba-shan Mountain Area of Shaanxi Province. It has been found that the crude persimmon extracts are complex mixtures containing vitamins, p-coumaric acid, gallic acid, catechin, flavonoids, carotenoids and condensed tannin and so on, which indicates the extracts of persimmon husk suitable to be used as green and eco-friendly corrosion inhibitors.

Findings

Extracts of persimmon husk were investigated, by using weight loss and potentiodynamic polarisation techniques, as green and eco-friendly corrosion inhibitors of Q235A steel in 1M HCl. The inhibition efficiency of the extracts varied with extract concentration from 10 to 1,000 mg/L. There are some synergistic effects between the extracts and KI, KSCN and HMTA. Potentiodynamic polarization studies indicate that extracts are mixed-type inhibitors. Besides, the extracts were screened for antibacterial activity against oil field microorganisms, and they showed good to moderate activity against SRB, IB and TGB.

Conclusions

The inhibition efficiency of the extracts varied with extract concentration from 10 to 1,000 mg/L, and the highest reaches to 65.1% with the con concentration of 1,000 mg/L WE. KI, KSCN and HMTA they can enhance the IE of WE effectively to 97.3% at most, but not effective for KI and KSCN to AE. Tafel polarisation measurements indicate the extracts behave as mixed type inhibitor. Investigation of the antibacterial activity against oil field microorganism showed the extracts can inhibit SRB, IB and TGB with moderate to highly efficiency under 1,000 mg/L, which makes extracts potential to be used as bifunctional oil field chemicals.

The free radical scavenging and antioxidant activities of pod and seed extract of Clitoria fairchildiana (Howard)- an underutilized legume

We evaluated the phenolic content and antioxidant capacities of pod and seed extracts (in methanol, ethanol, and water) of an underutilized legume, Clitoria fairchildiana (Howard). The antioxidant capacity of the extracts was determined using the ferric reducing antioxidant potential assay, and the free radical-scavenging capacity was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical-scavenging and ABTS assays. In addition, the total flavonoids, flavonols, and tannin contents were also determined. Overall, the methanol extracts of the pod contained high concentration of phenolics and showed high antioxidant capacities compared to seed extracts. In addition, a positive correlation was found between total phenol and tannin versus antioxidant capacity. Results of the present study indicate pods and seeds of C. fairchildiana to possess rich amount of natural antioxidants, and can be further explored for their possible use as a natural additive in food or in pharmaceutical industries.

Investigation of ginkgo biloba leave extracts as corrosion and Oil field microorganism inhibitors

Ginkgo biloba (Ginkgoaceae), originating from China, now distributes all over the world. Wide application of Ginkgo biloba extracts is determined by the main active substances, flavonoids and terpenoids, which indicates its extracts suitable to be used as an effective corrosion inhibitor. The extracts of Ginkgo biloba leave have been investigated on the corrosion inhibition of Q235A steel with weight loss and potentiodynamic polarisation techniques. The inhibition efficiency of the extracts varies with extract concentration. The extracts inhibit corrosion mainly by adsorption mechanism. Potentiodynamic polarisation studies show that extracts are mixed type inhibitors. The antibacterial activity of the extracts against oil field microorganism (SRB, IB and TGB) was also investigated.

1,2,3,4,6 Penta-O-galloyl-β-d-glucose, a bioactivity guided isolated compound from Mangifera indica inhibits 11β-HSD-1 and ameliorates high fat diet-induced diabetes in C57BL/6 mice

Methanolic leaf extract of Mangifera indica (MEMI) was subjected to bioactivity guided fractionation in order to identify the active antidiabetic constituent. 32 fractions were evaluated for possible 11β-HSD-1 inhibition activity under in vitro conditions. The EA-7/8-9/10-4 fraction was evolved as a most potent fraction among all the fractions and it was identified as well known gallotannin compound 1,2,3,4,6 penta-O-galloyl-β-d-glucose (PGG) by spectral analysis. Based on these results the PGG was further evaluated in ex vivo 11β-HSD-1 inhibition assay and high fat diet (HFD)-induced diabetes in male C57BL/6 mice. Single dose (10, 25, 50 and 100mg/kg) of PGG and carbenoxolone (CBX) have dose dependently inhibited the 11β-HSD-1 activity in liver and adipose tissue. Furthermore, HFD appraisal to male C57BL/6 mice caused severe hyperglycemia, hypertriglyceridemia, elevated levels of plasma corticosterone and insulin, increased liver and white adipose mass with increase in body weight was observed compare to normal control. Also, oral glucose tolerance was significantly impaired compare to normal control. Interestingly, post-treatment with PGG for 21 days had alleviated the HFD-induced biochemical alterations and improved oral glucose tolerance compare to HFD-control. In conclusion, the PGG isolated from MEMI inhibits 11β-HSD-1 activity and ameliorates HFD-induced diabetes in male C57BL/6 mice.

Interaction of Dihydromyricetin and α-Amylase

The interaction of dihydromyricetin (DMY) and α-amylase was investigated. The complex formed between DMY and α-amylase resulted in decreased antioxidant activity of DMY and the catalytic activity of the enzyme, as well as efficient quenching of the intrinsic fluorescence of α-amylase. An α-amylase molecule provides one binding site for a DMY molecule. These results will be useful for exploiting this compound to combat diseases efficiently.

Dietary quebracho tannins are not absorbed, but increase the antioxidant capacity of liver and plasma in sheep

A total of sixteen lambs were divided into two groups and fed two different diets. Of these, eight lambs were fed a control diet (C) and eight lambs were fed the C diet supplemented with quebracho tannins (C+T). The objective of the present study was to assess whether dietary quebracho tannins can improve the antioxidant capacity of lamb liver and plasma and if such improvement is due to a direct transfer of phenolic compounds or their metabolites, to the animal tissues. Feed, liver and plasma samples were purified by solid-phase extraction (SPE) and analysed by liquid chromatography–MS for phenolic compounds. Profisitinidin compounds were identified in the C+T diet. However, no phenolic compounds were found in lamb tissues. The liver and the plasma from lambs fed the C+T diet displayed a greater antioxidant capacity than tissues from lambs fed the C diet, but only when samples were not purified with SPE. Profisetinidin tannins from quebracho seem not to be degraded or absorbed in the gastrointestinal tract. However, they induced antioxidant effects in animal tissues.

Protein quality evaluation twenty years after the introduction of the protein digestibility corrected amino acid score method

In 1989 the Joint FAO/WHO Expert Consultation on Protein Quality Evaluation recommended the use of the Protein Digestibility Corrected Amino Acid Score (PDCAAS) method for evaluating protein quality. In calculating PDCAAS, the limiting amino acid score (i.e., ratio of first limiting amino acid in a gram of target food to that in a reference protein or requirement) is multiplied by protein digestibility. The PDCAAS method has now been in use for 20 years. Research emerging during this time has provided useful data on various aspects of protein quality evaluation that has made a review of the current methods used in assessing protein quality necessary. This paper provides an overview of the use of the PDCAAS method as compared to other methods and addresses some of the key challenges that remain in regards to protein quality evaluation. Furthermore, specific factors influencing protein quality including the effects of processing conditions and preparation methods are presented. Protein quality evaluation methods and recommended protein intakes currently used in different countries vis-à-vis the WHO/FAO/UNU standards are further provided. As foods are frequently consumed in complement with other foods, the significance of the PDCAAS of single protein sources may not be evident, thus, protein quality of some key food groups and challenges surrounding the calculation of the amino acid score for dietary protein mixtures are further discussed. As results from new research emerge, recommendations may need to be updated or revised to maintain relevance of methods used in calculating protein quality.

The susceptibility of soil enzymes to inhibition by leaf litter tannins is dependent on the tannin chemistry, enzyme class and vegetation history

By inhibiting soil enzymes, tannins play an important role in soil carbon (C) and nitrogen (N) mineralization. The role of tannin chemistry in this inhibitory process, in conjunction with enzyme classes and isoforms, is less well understood. Here, we compared the inhibition efficiencies of mixed tannins (MTs, mostly limited to angiosperms) and condensed tannins (CTs, produced mostly by gymnosperms) against the potential activity of β-glucosidase (BG), N-acetyl-glucosaminidase (NAG), and peroxidase in two soils that differed in their vegetation histories. Compared with CTs, MTs exhibited 50% more inhibition of almond (Prunus dulcis) BG activity and greater inhibition of the potential NAG activity in the gymnosperm-acclimatized soils. CTs exhibited lower BG inhibition in the angiosperm-acclimated soils, whereas both types of tannins exhibited higher peroxidase inhibition in the angiosperm soils than in gymnosperm soils. At all of the tested tannin concentrations, irrespective of the tannin type and site history, the potential peroxidase activity was inhibited two-fold more than the hydrolase activity and was positively associated with the redox-buffering efficiency of tannins. Our finding that the inhibitory activities and mechanisms of MTs and CTs are dependent on the vegetative history and enzyme class is novel and furthers our understanding of the role of tannins and soil isoenzymes in decomposition.

Ultrathin polymeric coatings based on hydrogen-bonded polyphenol for protection of pancreatic islet cells

Though transplantation of pancreatic islet cells has emerged as a promising treatment for Type 1 diabetes its clinical application remains limited due to a number of limitations including both pathogenic innate and adaptive immune responses. We report here on a novel type of multifunctional cytoprotective material applied to coat living pancreatic islets. The coating utilizes hydrogen-bonded interactions of a natural polyphenol (tannic acid) with poly(N-vinylpyrrolidone) deposited on the islet surface via non-ionic layer-by-layer assembly. We demonstrate that the coating is conformal over the surface of mammalian islets including those derived from rat, non-human primate (NHP), and human. In contrast to unmodified controls, the coated islets maintain their viability and β-cell functionality for at least 96 hours in vitro. We also determine that the coating demonstrates immunomodulatory cytoprotective properties suppressing pro-inflammatory cytokine synthesis in stimulated bone marrow-derived macrophages and diabetogenic BDC-2.5 T cells. The coating material combines high chemical stability under physiologically relevant conditions with capability of suppressing cytokine synthesis, crucial parameters for prolonged islet integrity, viability, and function in vivo. Our study offers new opportunities in the area of advanced multifunctional materials to be used for a cell-based transplantation therapy.

Protective effect of blackcurrant on liver cell membrane of rats intoxicated with ethanol

Chronic ethanol intoxication oxidative stress participates in the development of many diseases. Nutrition and the interaction of food nutrients with ethanol metabolism may modulate alcohol toxicity. One such compound is blackcurrant, which also has antioxidant abilities. We investigated the effect of blackcurrant as an antioxidant on the composition and electrical charge of liver cell membranes in ethanol-intoxicated rats. Qualitative and quantitative phospholipid composition and the presence of integral membrane proteins were determined by high-performance liquid chromatography. Electrophoresis was used to determine the surface charge density of the rat liver cell membranes. Ethanol intoxication is characterized by changes in cell metabolism that alter the structure and function of cell membrane components. Ethanol increased phospholipid levels and altered the level of integral proteins as determined by decreased phenylalanine, cysteine, and lysine. Ethanol significantly enhanced changes in the surface charge density of the liver cell membranes. Administration of blackcurrant to rats intoxicated with ethanol significantly protected lipids and proteins against oxidative modifications. It is possible that the beneficial effect of blackcurrant is connected with its abilities to scavenge free radicals and to chelate metal ions.

Characterization and antioxidant activity of the complex of tea polyphenols and oat β-glucan

Few data are available about the effects of complexation of polyphenols with polysaccharide on their bioavailability. The complex of tea polyphenols (TP) with oat β-glucan was characterized by ultraviolet-visible spectrometry, Fourier transform infrared spectrometry, differential scanning calorimetry, atomic force microscopy, and solid-state (13)C NMR spectroscopy. The results indicated that the bonds which governed the interaction between TP and oat β-glucan were strong hydrogen bonds. The in vitro antioxidant activity of TP, β-glucan, their complex, and physical mixture was assessed using four systems, namely, DPPH(•), OH(•), and O(2)(•-) scavenging activities and reducing power. The complexation and blending of TP and β-glucan exhibited different impacts on the index of in vitro and in vivo antioxidant capacities. In the concentration range of 0.5-2.5 mg mL(-1), the complex had highest O(2)(•-) scavenging activity, whereas the highest OH(•) scavenging activity was found with the physical mixture. For antioxidant testing in vivo, there was no significant difference between the complex and the physical mixture in terms of glutathione peroxidase activity and levels of malondialdehyde and total antioxidant capacity in serums. However, the complex exhibited much higher activities of superoxide dismutase and glutathione peroxidase in livers than the physical mixture. The present study provided a deeper understanding of the influence of molecular interaction between TP and oat β-glucan on their antioxidant activities.

Bioactivities and antiradical properties of millet grains and hulls

Antioxidant activities of phenolic extracts of kodo and pearl millet whole grains, dehulled grains, and hulls were examined by monitoring inhibition of radical-induced DNA scission, human low-density lipoprotein (LDL) cholesterol, and phospholipid liposome oxidation. Total phenolic content (TPC), hydroxyl and peroxyl radical inhibition, and antiproliferative activities against HT-29 cells were also determined. Major hydroxycinnamic acids in dehulled grains and hulls were identified and quantified using HPLC. Phenolic extract of kodo millet exhibited higher inhibition activities against oxidation of LDL cholesterol and liposome than that of pearl millet. All phenolic extracts exhibited a dose-dependent inhibition of DNA scission. The TPC of hulls of kodo and pearl millets were 3 times higher than those of their corresponding whole grains. At the end of 96 h of incubation, kodo millet extracts inhibited cell proliferation in the range of 75-100%. Antioxidant activities of phenolic extracts were in the order hull > whole grain > dehulled grain. Dehulling reduced the antioxidant potential of whole millet grains. Ferulic and p-coumaric acids were the major hydroxycinnamic acids, and their contents ranged from 17.8 to 1685 μg/g defatted meal and from 3.5 to 680 μg/g defatted meal, respectively. Dehulled grains, as well as the hull fraction, may serve as potential sources of nutraceutical and functional food ingredients in health promotion.

The genome-wide expression profile of 1,2,3,4,6-penta-O-galloyl-β-D-glucose-treated MDA-MB-231 breast cancer cells: molecular target on cancer metabolism

1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG), a polyphenolic compound isolated from Rhus chinensis Mill. PGG has been known to have anti-tumor, anti-angiogenic and anti-diabetic activities. The present study revealed another underlying molecular target of PGG in MDA-MB-231 breast cancer cells by using Illumina Human Ref-8 expression BeadChip assay. Through the Beadstudio v3 micro assay program to compare the identified genes expressed in PGG-treated MDA-MB-231 cells with untreated control, we found several unique genes that are closely associated with pyruvate metabolism, glycolysis/gluconeogenesis and tyrosine metabolism, including PC, ACSS2, ACACA, ACYP2, ALDH3B1, FBP1, PRMT2 and COMT. Consistent with microarray data, real-time RT-PCR confirmed the significant down-regulation of these genes at mRNA level in PGG-treated MDA-MB-231 cells. Our findings suggest the potential of PGG as anticancer agent for breast cancer cells by targeting cancer metabolism genes.

Truly nonionic polymer shells for the encapsulation of living cells

Engineering surfaces of living cells with natural or synthetic compounds can mediate intercellular communication and provide a protective barrier from hostile agents. We report on truly nonionic hydrogen-bonded LbL coatings for cell surface engineering. These ultrathin, highly permeable polymer membranes are constructed on living cells without the cationic component typically employed to increase the stability of LbL coatings. Without the cytotoxic cationic PEI pre-layer, the viability of encapsulated cells drastically increases to 94%, in contrast to 20% viability in electrostatically-bonded LbL shells. Moreover, the long-term growth of encapsulated cells is not affected, thus facilitating efficient function of protected cells in hostile environment.

High molecular weight persimmon tannin ameliorates cognition deficits and attenuates oxidative damage in senescent mice induced by D-galactose

Mice were subcutaneously injected with d-galactose (D-gal, 150 mg/kg per day) for 6 weeks and were administered high molecular weight persimmon condensed tannin (HMWPT) simultaneously. After 6 weeks of treatment, the animal behavior was observed in the open field test and water maze test, and the morphology of hippocampus and skin were checked. Meanwhile, the activities of antioxidant enzymes, the levels of non-enzymatic antioxidants, as well as malondialdehyde (MDA) were evaluated. The results indicated that HMWPT markedly inhibited the d-gal induced learning and memory impairment in both open field test and Morris water maze. Biochemical examination revealed that HMWPT significantly increased the decreased activities of superoxide dismutase (SOD), catalase (CAT), elevated the lowered total anti-oxidation capability (T-AOC), glutathione (GSH) and hydroxyproline (Hyp) contents (p<0.01 or p<0.05), and decreased the raised monoamine oxidase (MAO), total cholinesterase (TChE) activities and MDA level (p<0.01) in serum, liver or brain of aging mice induced by d-gal in a dose-dependent fashion. Furthermore, HMWPT significantly and (p<0.01) attenuated the d-gal induced number decrease, neuronal degeneration and karyopycnosis in cells in the hippocampus and decrease of thickness of skin epidermis and dermis.

Plant polyphenols: chemical properties, biological activities, and synthesis

Eating five servings of fruits and vegetables per day! This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why? The answer is in fact still under scientific scrutiny, but a particular class of compounds naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really? What are their physicochemical properties? How do they express their biological activity? Are they really valuable for disease prevention? Can they be used to develop new pharmaceutical drugs? What recent progress has been made toward their preparation by organic synthesis? This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research.

Antimutagenic, antigenotoxic and antioxidant activities of phenolic-enriched extracts from Teucrium ramosissimum: combination with their phytochemical composition

The evaluation of the mutagenic and antimutagenic actions of extracts obtained from aerial part of Teucrium ramosissimum was assayed using the Salmonella typhimurium assay system. The effect of the same extracts on genotoxicity and SOS response induced by aflatoxin B(1) as well as nitrofurantoin was investigated in a bacterial assay system, i.e., the SOS chromotest with Escherichia coli PQ37. The different extracts showed no mutagenicity when tested with Salmonella typhimurium strains TA100, TA98 and TA1535 either with or without S9 mix. In contrast, our results prove that T. ramosissimum extracts possess antimutagenic effects against sodium azide, aflatoxin B1, benzo[a]pyrene and 4-nitro-o-phenylenediamine. Moreover, the T. ramosissimum tested extracts exhibited no genotoxicity either with or without the external S9 activation mixtures. However, all the extracts significantly decreased the genotoxicity induced by aflatoxin B(1) and nitrofurantoin. The result obtained by the Ames test confirms those of SOS chromotest. Antioxidant capacity of the tested extracts was evaluated using the enzymatic (xanthine/xanthine oxidase assay) and the non enzymatic (NBT/riboflavine, DPPH and ABTS assays) systems. All extracts exhibited high antioxidant activity except the chloroform and the methanol extracts in DPPH and NBT/riboflavine assays respectively. Our results underline the potential of T. ramosissimum to avoid mutations and also its antioxidant potential.