Mechanisms of action of antioxidants as exemplified in vegetables, tomatoes and tea

Antioxidant capacity of simplified oxygen heterocycles and proposed derivatives by theoretical calculations

CONTEXT

Some structural properties can be involved in the antioxidant capacity of several polyphenol derivatives, among them their simplified structures. This study examines the contribution of simplified structure for the antioxidant capacity of some natural and synthetic antioxidants. The resonance structures were related to the π-type electron system of carbon-carbon double bonds between both phenyl rings. Trans-resveratrol, phenyl-benzofuran, phenyl-indenone, and benzylidene-benzofuranone are the best basic antioxidant templates among the simplified derivatives studied here. Additionally, the stilbene moiety was found on the molecules with the best antioxidant capacity. Furthermore, our investigation suggests that these compounds can be used as antioxidant scaffold for designing and developing of new promising derivatives.

METHODS

To investigate the structure-antioxidant capacity for sixteen simplified natural and proposed derivatives we have employed density functional theory and used Gaussian 09. Our DFT calculations were performed using the B3LYP functional and the 6-31+G(d,p) basis set. All electron transfer mechanisms were investigated by using values of HOMO, ionization potential, energy affinity, stabilization energies, and spin density distributions.

Oxidative Stability of Vacuum-Packed Chicken Wings Marinated with Fruit Juices during Frozen Storage

Antioxidants present in fruits and vegetables have a potential to reduce disease risk, and increase the shelf life of food products by reducing lipid oxidation. The effect of marination with antioxidants-rich fruit juices on quality characteristics of vacuum-packed chicken wings were examined during frozen storage. Chicken wings were mixed separately with marinades containing pineapple juice, June plum juice, and mango juice and kept for 12 h and 24 h. Three best marination conditions were selected based on a sensory evaluation. Antioxidant activity and total phenolic content of fruit juices, and marinade uptake, and marinade loss of marinated chicken wings were determined. In addition, vacuum packed marinated chicken wings were tested for pH, water holding capacity (WHC), 2-thiobarbituric acid reactive substances (TBARS) value and antioxidant activity over a 4-wk frozen storage. The best sensory properties were reported from chicken wings marinated with pineapple juice for 24 h, mango juice for 24 h, and June plum juice for 12 h (p<0.05) compared to other marinade-time combinations. Mango juice showed the highest antioxidant activity (92.2%) and total phenolic content (38.45 μg/mL; p<0.05) compared to other fruit juices. The pH and WHC of vacuum-packed chicken wings were slightly decreased over the frozen storage (p<0.05). Moreover, chicken wings marinated with mango juice had the lowest TBARS values and the highest 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical scavenging activity. In conclusion, mango juice was selected among tested as the most effective marinade for enhancing the oxidative stability of lipid while maintaining the other meat quality traits of vacuum-packed chicken wings.

Differential Effects of Green Tea Powders on the Protection of Brown Tsaiya and Kaiya Ducklings against Trichothecene T-2 Toxin Toxicity

Simple Summary

The objective of this study is to examine the effects of T-2 toxin (T-2) and green tea powders (GTP) on growth performance, hematology, and pathology parameters in Brown Tsaiya ducklings (BTDs) and Kaiya ducklings (KDs). T-2 toxin shows a strong and differential toxicity in growth suppression, as well as abnormalities in the hematological and pathological parameters of BTDs and KDs. We found that GTP could potentially prevent T-2-induced poor growth performance and improve some hematological parameters. Moreover, BTDs were more sensitive than KDs in terms of responses to T-2 toxicity and GTP detoxification.

Abstract

A 3-week feeding trial in a 3 × 2 × 2 factorial design was conducted with three concentrations (0, 0.5, and 5 mg/kg) of T-2 toxin (T-2) and two levels (0% and 0.5%) of green tea powder (GTP) supplements used in the diets of female brown Tsaiya ducklings (BTDs) and Kaiya ducklings (KDs), respectively. Breed had a significant effect on the growth performances and the relative weights of organs and carcass. In general, the growth performances of KDs were better than BTDs. The relative weights of organs and carcass of BTDs were typically heavier than those of KDs; however, the breast of KDs was heavier than those of BTDs. Both ducklings received 5 mg/kg of T-2 blended in the diet showed lower feed intake and body weight gain (BWG) in the second and the third week. The diet containing 5 mg/kg of T-2 and 0.5% GTP improved the BWG compared to those fed the diet supplemented with 5 mg/kg of T-2 without GTP in BTDs. Ducklings fed the diet containing 5 mg/kg of T-2 induced hypocalcemia and hypomagnesemia, as well as decreased concentrations of creatine phosphokinase and alkaline phosphatase. The concentrations of blood urea nitrogen (BUN) and glutamate oxaloacetate transaminase (GOT) were increased in KDs and BTDs fed the diet containing 5 mg/kg of T-2 without GTP, respectively. However, duckling diets containing 5 mg/kg of T-2 with 0.5% GTP lowered concentrations of BUN and GOT in the blood plasma of KDs and BTDs, respectively. The diet containing 5 mg/kg of T-2 increased the relative kidney weight but decreased the relative breast weight of ducklings. Enlarged gizzards and reduced relative leg weights were observed in BTDs fed the diets containing 5 mg/kg of T-2. In summary, BTDs are more sensitive than KDs in responding to T-2 toxicity and GTP detoxification. Green tea powder has detoxification ability and could potentially mitigate T-2 toxicity on BWG, BUN, and GOT in ducklings.

Twenty-five years of total antioxidant capacity measurement of foods and biological fluids: merits and limitations

This review summarises 25 years of investigations on antioxidants research in foods and biological fluids and critically analyses the merits and limitations of using the total antioxidant capacity (TAC) measurement in the metabolomic era. An enormous bulk of knowledge was produced regarding the antioxidant capacity of foods and large TAC databases were developed. A direct link between a food TAC value and any health benefit is erroneous and has led to several cases of consumer deception. However, the striking epidemiological evidence associating a high dietary TAC with some disease prevention and the availability of well-constructed TAC databases deserve attention and must be taken into account to establish the usefulness of measuring TAC in both foods and biological samples. The in vivo TAC measurement, usually performed in plasma, is influenced by many external factors, such as dietary habits, as well as environmental and behavioural factors, which are integrated towards homeostatic control by fine physiological mechanisms with high inter-individual variability. Therefore, plasma TAC cannot be considered as a unique biomarker of individual antioxidant status. However, the combined evaluation of plasma TAC with known markers of disease, individual metabolism, inflammation and genetics, as well as with markers of gut microbiota composition and activity, may lead to the identification of populations that are more responsive to food/diet TAC. In this framework, the appropriate use of TAC measurement both in food and in vivo can still provide support for the interpretation of complex phenomena and be a tool for sample screening when making a quick decision toward in-depth research investigations. © 2018 Society of Chemical Industry.

Quercetin induced cell apoptosis and altered gene expression in AGS human gastric cancer cells

Quercetin is one of the natural components from natural plant and it induces cell apoptosis in many human cancer cell lines. However, no available reports show that quercetin induces apoptosis and altered associated gene expressions in human gastric cancer cells, thus, we investigated the effect of quercetin on the apoptotic cell death and associated gene expression in human gastric cancer AGS cells. Results indicated that quercetin induced cell morphological changes and reduced total viability via apoptotic cell death in AGS cells. Furthermore, results from flow cytometric assay indicated that quercetin increased reactive oxygen species (ROS) production, decreased the levels of mitochondrial membrane potential (ΔΨ_m ), and increased the apoptotic cell number in AGS cells. Results from western blotting showed that quercetin decreased anti-apoptotic protein of Mcl-1, Bcl-2, and Bcl-x but increased pro-apoptotic protein of Bad, Bax, and Bid. Furthermore, quercetin increased the gene expressions of TNFRSF10D (Tumor necrosis factor receptor superfamily, member 10d, decoy with truncated death domain), TP53INP1 (tumor protein p53 inducible nuclear protein 1), and JUNB (jun B proto-oncogene) but decreased the gene expression of VEGFB (vascular endothelial growth factor B), CDK10 (cyclin-dependent kinase 10), and KDELC2 (KDEL [Lys-Asp-Glu-Leu] containing 2) that are associated with apoptosis pathways. Thus, those findings may offer more information regarding the molecular, gene expression, and signaling pathway for quercetin induced apoptotic cell death in human gastric cancer cells.

Quercetin induced apoptosis of human oral cancer SAS cells through mitochondria and endoplasmic reticulum mediated signaling pathways

Oral cancer is a cause of cancer-associated mortality worldwide and the treatment of oral cancer includes radiation, surgery and chemotherapy. Quercetin is a component from natural plant products and it has been demonstrated that quercetin is able to induce cytotoxic effects through induction of cell apoptosis in a number of human cancer cell lines. However, there is no available information to demonstrate that quercetin is able to induce apoptosis in human oral cancer cells. In the present study, the effect of quercetin on the cell death via the induction of apoptosis in human oral cancer SAS cells was investigated using flow cytometry, Annexin V/propidium iodide (PI) double staining, western blotting and confocal laser microscopy examination, to test for cytotoxic effects at 6–48 h after treatment with quercetin. The rate of cell death increased with the duration of quercetin treatment based on the results of a cell viability assay, increased Annexin V/PI staining, increased reactive oxygen species and Ca²⁺ production, decreased the levels of mitochondrial membrane potential (ΔΨ_m), increased proportion of apoptotic cells and altered levels of apoptosis-associated protein expression in SAS cells. The results from western blotting revealed that quercetin increased Fas, Fas-Ligand, fas-associated protein with death domain and caspase-8, all of which associated with cell surface death receptor. Furthermore, quercetin increased the levels of activating transcription factor (ATF)-6α, ATF-6β and gastrin-releasing peptide-78 which indicated an increase in endoplasm reticulum stress, increased levels of the pro-apoptotic protein BH3 interacting-domain death antagonist, and decreased levels of anti-apoptotic proteins B-cell lymphoma (Bcl) 2 and Bcl-extra large which may have led to the decreases of ΔΨ_m. Additionally, confocal microscopy suggested that quercetin was able to increase the expression levels of cytochrome c, apoptosis-inducing factor and endonuclease G, which are associated with apoptotic pathways. Therefore, it is hypothesized that quercetin may potentially be used as a novel anti-cancer agent for the treatment of oral cancer in future.

N 1, N14-diferuloylspermine as an antioxidative phytochemical contained in leaves of Cardamine fauriei

Most Brassicaceae vegetables are ideal dietary sources of antioxidants beneficial for human health. Cardamine fauriei (Ezo-wasabi in Japanese) is a wild, edible Brassicaceae herb native to Hokkaido, Japan. To clarify the main antioxidative phytochemical, an 80% methanol extraction from the leaves was fractionated with Diaion® HP-20, Sephadex® LH-20, and Sep-Pak® C18 cartridges, and the fraction with strong antioxidant activity depending on DPPH method was purified by HPLC. Based on the analyses using HRESIMS and MS/MS, the compound might be N1, N14-diferuloylspermine. This rare phenol compound was chemically synthesized, whose data on HPLC, MS and 1H NMR were compared with those of naturally derived compound from C. fauriei. All results indicated they were the same compound. The radical-scavenging properties of diferuloylspermine were evaluated by ORAC and ESR spin trapping methods, with the diferuloylspermine showing high scavenging activities of the ROO·, O2·−, and HO· radicals as was those of conventional antioxidants.

Stereospecific inhibition of nitric oxide production in macrophage cells by flavanonols: Synthesis and the structure-activity relationship. Part 2

To explore the structure-activity relationships of flavanonols on the inhibition of nitric oxide (NO) production in RAW 264.7 cells, we have prepared a series of synthetic flavanonols. In our previous study, the 2',3'-dihydroxyphenyl substructure was found to be the most potent B ring substructure among the flavanonols having 3,5,7-trihydroxychroman-4-one as the A/C ring. In this study, we examined the effect of diverse substitutions on the A ring of the 2-(2,3-dihydroxyphenyl)-3-hydroxychroman-4-one scaffold, i.e., by fixing the B ring to the 2',3'-dihydroxyphenyl substructure. Eighteen stereoisomers and 4 racemic mixtures were prepared, and their inhibitory potency on NO production in RAW 264.7 cells was tested. We observed higher inhibitory activity in the (2R,3R) stereoisomers than in the (2S,3S) stereoisomers. The presence of a hydroxy or a methoxy group at the 7-postiion enhanced the inhibitory potency, and the additional substitutions at the 6- or 8-position in the A ring increased potency and stereospecificity. A representative compound, (2R,3R)-2',3',7,8-tetrahydroxyflavanonol 5e, had an IC₅₀ value of 17µM, whereas its (2S,3S) stereoisomer did not inhibit NO production at all at a concentration of 100µM. In this study, it was necessary to determine the absolute configuration of the stereoisomers of the synthesized flavanonols that carry methoxy substitutions in the A ring. The procedure to determine their absolute configuration by the CD excitation chirality method is also discussed.

Grasslands: A Source of Secondary Metabolites for Livestock Health

The need for environmentally friendly practices in animal husbandry, in conjunction with the reduction of the use of synthetic chemicals, leads us to reconsider our agricultural production systems. In that context, grassland secondary metabolites (GSMs) could offer an alternative way to support to livestock health. In fact, grasslands, especially those with high dicotyledonous plant species, present a large, pharmacologically active reservoir of secondary metabolites (e.g., phenolic compounds, alkaloids, saponins, terpenoids, carotenoids, and quinones). These molecules have activities that could improve or deteriorate health and production. This Review presents the main families of GSMs and uses examples to describe their known impact on animal health in husbandry. Techniques involved for their study are also described. A particular focus is put on anti-oxidant activities of GSMs. In fact, numerous husbandry pathologies, such as inflammation, are linked to oxidative stress and can be managed by a diet rich in anti-oxidants. The different approaches and techniques used to evaluate grassland quality for livestock health highlight the lack of efficient and reliable technics to study the activities of this complex phytococktail. Better knowledge and management of this animal health resource constitute a new multidisciplinary research field and a challenge to maintain and valorize grasslands.

Note: A Comparative Study on the in Vitro Antiradical Activity and Hydroxyl Free Radical Scavenging Activity in Aged Red Wines

The antiradical and hydroxyl free radical scavenging activities were estimated in twenty-five, aged red wines from different areas in Greece. The antiradical activity (AAR) was determined by means of the wellknown DPPH• method, and its values ranged from 24.7 to 125.1. A novel, chemiluminescence-based, highly sensitive assay was applied for determination of the hydroxyl free radical scavenging activity (SAHFR), which varied from 1.62 to 12.22 mM quercetin equivalents. The values from the two assays correlated very well (r2 =0.8542, P<0.001), which confirmed an important relationship between SAHFR and AAR. This tendency in aged red wines, which may be significant in evaluating the antioxidant behaviour of red wine polyphenols, is discussed on the basis of previous research and relevant data.

Anti-clastogenic effect of b-glucan extracted from barley towards chemically induced DNA damage in rodent cells

b-Glucan (BG) was tested in vitro to determine its potential clastogenic and/or anti-clastogenic activity, and attempts were made to elucidate its possible mechanism of action by using combinations with an inhibitor of DNA polymerase. The study was carried out on cells deficient (CHO-k1) and cells proficient (HTC) in phases I and II enzymes, and the DNA damage was assessed by the chromosomal aberration assay. BG did not show a clastogenic effect, but was anti-clastogenic in both cell lines used, and at all concentrations tested (2.5, 5 and 10 mg/mL) in combination with damage inducing agents (methylmethane sulfonate in cell line CHO-k1, and methylmethane sulfonate or 2-aminoanthracene in cell line HTC). BG also showed a protective effect in the presence of a DNA polymerase b inhibitor (cytosine arabinoside-3-phosphate, Ara-C), demonstrating that BG does not act through an anti-mutagenic mechanism of action involving DNA polymerase b.

Dietary patterns and benign breast diseases: a case-control study

Several studies have investigated the relation between benign breast diseases (BBD) and food intake. However, dietary patterns of these patients have not been taken into consideration up to now. The aim of this study is to determine the association between dietary patterns and BBD. In this case-control study, ninety-six patients with BBD and seventy controls were selected from women attending the Iranian Center for Breast Cancer affiliated with Academic Center for Education, Culture and Research. Demographic, physical activity and semi-quantitative FFQ were completed. The main dietary patterns were extracted by factor analysis. Two major dietary patterns emerged: Healthy dietary pattern including fish, poultry, eggs, low-fat dairy products, vegetables, legumes, nuts and seeds, whole grains, oil and mayonnaise, olives, fruits; and Unhealthy dietary pattern including red meats, organ and processed meats, high-fat dairy products, refined grains, sweets and desserts, animal and solid fats. After adjustment for age, BMI and energy intake, the participants in the highest tertile of Healthy dietary pattern (OR 0·44; 95 % CI 0·20, 0·99) were less likely to have BBD compared with those in the first tertile. After adjustment for other confounding variables, this relationship still remained close to significant level. However, higher consumption of Unhealthy dietary pattern was not associated with the risk of BBD. In conclusion, Healthy dietary pattern might be inversely associated with the risk of BBD; however, this result should be interpreted with caution. Future studies are needed to confirm our findings.

Ellagitannins and Flavan-3-ols from Raspberry Pomace Modulate Caecal Fermentation Processes and Plasma Lipid Parameters in Rats

Raspberry pomace is a source of polyphenols, which nutritional and health promoting properties are not sufficiently known. The aim of this 8-weeks study was to scrutinize if raspberry extracts (REs) with different ellagitannins to flavan-3-ols ratios might favorably affect the caecal fermentation processes and blood lipid profile in rats. Forty male Wistar rats were fed with a standard diet or its modification with two types of REs (E1 and E2) characterized by different ratios of ellagitannins to flavan-3-ols (7.7 and 3.1 for E1 and E2, respectively) and added to a diet at two dosages of polyphenolic compounds (0.15 and 0.30% of a diet; L and H treatments, respectively). Irrespective of polyphenols dietary level, both REs reduced the activity of bacterial β-glucuronidase, increased production of butyric acid in the caecum and reduced triacylglycerols in blood plasma. The E1 treatment at both dosages caused more effective reduction in the concentration of ammonia and elevated acetate level in the caecal digesta than E2. On the other hand, only the E2 treatment lowered value of the atherogenic index when compared with control group. When comparing dosages of REs, a higher one was more potent to reduce the activity of bacterial β-glucosidase, β-, α-galactosidase and lowered value of the HDL profile in plasma. To conclude, REs may favorably modulate the activity of the caecal microbiota and blood lipid profile in rats; however, the intensity of these effects may be related to the dosages of dietary polyphenols and to their profile, e.g., ellagitannins to flavan-3-ols ratio.

Synergistic anticancer activity of biologicals from green and black tea on DU 145 human prostate cancer cells

There is considerable interest in the potential of botanicals in preventing and/or alleviating chronic ailments. Among the most studied botanicals are compounds present in green and black teas. Nontoxic tea polyphenols are potent antioxidants, and they also modulate several signalling pathways and inhibit proteins such as MMP-9 or protein plasminogen activator system, making them very attractive potential therapeutics. One criticism of the prophylactic or therapeutic use of green or black tea polyphenols was presumably the poor bioavailability of these chemicals when ingested. However, studies have shown that epigallocatechin-3-gallate (EGCG) and theaflavin (TF) can be detected in the small and large intestine, liver, and prostate of experimental animals after consumption of tea extracts. In particular, a study was carried out on 20 men scheduled for prostatectomy, who were assigned to consume teas for five days before surgery. Tea polyphenols were detected in the prostate. This fact contradicts the common misconception of poor bioavailability of TF and EGCG and makes feasible the application of green or black tea polyphenols as prophylactic and therapeutic agents. Theaflavins and catechins seem to act on cancer cells largely through different pathways, so utilisation of both could offer synergistic anticancer effects, but so far no work has been done on the cumulative effects of EGCG and TF on prostate cancer. Therefore, in this study we have investigated if EGCG in combination with TF can reduce the rate of prostate cancer growth, and we have observed greater cell death compared to application of either TF or EGCG alone.

Stevia rebaudiana Bert. leaf extracts as a multifunctional source of natural antioxidants

The aim of the presented study was to characterize the content and biological activity of extracts prepared from dried Stevia rebaudiana leaves with potential application in the food or cosmetic industry. Aqueous (A), ethanolic (E) and glycol-aqueous (GA) extracts were analyzed for the content of polyphenols and proteins, showing that the highest amount of phenols (15.50 mg/g) and flavonoids (3.85 mg/g) contained GA. All extracts contained significant amount of protein (69.40–374.67 mg/g). Between analyzed stevia extracts (HPLC) GA contained the highest amount of polyphenols, especially ferulic (5.50 mg/g) and rozmaric (4.95 mg/g) acids derivates. The highest antiradical activity against DPPH^• and ABTS^•+ was noted for GA and E (IC₅₀ = 0.38 and 0.71 µg flavonoids/mL). The highest ability to chelate Fe²⁺ was observed for E (IC₅₀ = 2.08 µg flavonoids/mL). Stevia extracts were also analyzed for their cytotoxicity and fibroblast irritation potential in vitro. E and GA were the most cytotoxic and irritating, probably due to the high content of biologically active phytochemicals. On the other hand, a extract was the most tolerable by the cells. To summarize, the presented study evaluated the potential application of A, E and GA stevia extracts as natural source of antioxidants in the food and cosmetic industry.

Protection against chemotaxis in the anti-inflammatory effect of bioactives from tomato ketchup

The consumption of tomato products has been associated with a decreased risk for chronic inflammatory diseases. In this study, the anti-inflammatory potential of tomato ketchup was evaluated by studying the effect of tomato ketchup extracts and bioactives from tomato ketchup on human monocytes and vascular endothelial cells (HUVEC). HUVEC were pre-treated for 1 h with either individual bioactives (7.5 µM lycopene, 1.4 µM α-tocopherol or 55 µM ascorbic acid) or a combination of these three compounds, or with the hydrophilic or lipophilic tomato ketchup extracts or with the two extracts combined. After the pretreatment, the cells were washed and challenged with TNF-α (10 ng/ml) for 6 h. The medium was used for the determination of the release of cytokines and the chemotaxis of monocytes. Inflammatory protein expression and production were assayed with real-time RT-PCR and ELISA. It was found that tomato ketchup extracts significantly reduced gene expression and release of the pro-inflammatory cytokines TNF-α and IL-8 in HUVEC after the inflammatory challenge, whereas the release of the anti-inflammatory cytokine IL-10 was increased. Chemotaxis was effectively impeded as demonstrated by a reduced monocyte migration. This effect correlated with the reduction of IL-8 production in the presence of the test compounds and extracts. The results consistently emphasize the contribution of lycopene to the anti-inflammatory effect of tomato ketchup. Other compounds in tomato ketchup such as α-tocopherol and ascorbic acid appeared to strengthen the anti-inflammatory effect of lycopene. The tomato ketchup extracts subtly interfered with several inflammatory phases that inhibit chemotaxis. Such a pleotropic mode of action exemplifies its potential mitigation of diseases characterized by prolonged low grade inflammation.

Revisiting "Vegetables" to combat modern epidemic of imbalanced glucose homeostasis

Vegetables have been part of human food since prehistoric times and are considered nutritionally necessary and good for health. Vegetables are rich natural resource of biological antioxidants and possess capabilities of maintaining glucose homeostasis. When taken before starch-rich diet, juice also of vegetables such as ridge gourd, bottle gourd, ash gourd, chayote and juice of leaves of vegetables such as radish, Indian Dill, ajwain, tropical green amaranth, and bladder dock are reported to arrest significantly the rise in postprandial blood glucose level. Juice of vegetables such as ash gourd, squash gourd, and tropical green amaranth leaves are observed to tone-down sweet-beverages such as sucrose, fructose, and glucose-induced postprandial glycemic excursion. On the other hand, juice of egg-plant and juice of leaves of Ceylon spinach, Joyweed, and palak are reported to augment starch-induced postprandial glycemic excursion; and juice of leaves of Ceylon spinach, Joyweed, and radish supplement to the glucose-induced postprandial glycemia. Vegetables possess multifaceted antihyperglycemic activities such as inhibition of pancreatic α-amylase and intestinal α-glucosidase, inhibition of protein-tyrosine phosphatase 1β in liver and skeletal muscles, and insulin mimetic and secretagogue activities. Furthermore, they are also reported to influence polyol pathway in favor of reducing development of oxidative stress, and consequently the development of diabetic complications. In the wake of emergence of modern maladaptive diet-induced hyperglycemic epidemic therefore, vegetables may offer cost-effective dietary regimen to control diet-induced glycemic over load and future development of diabetes mellitus. However, for vegetables have been reported to do both, mitigate as well as supplement to the diet-induced postprandial glycemic load, care is required in selection of vegetables when considered as medicament.

Strawberry ellagitannins thwarted the positive effects of dietary fructooligosaccharides in rat cecum

Forty-eight male Wistar rats were fed diets containing low (0.051% of diet) or high (0.153% of diet) levels of an ellagitannin-rich (ET) strawberry extract with dietary fructooligosaccharides (FOS) or cellulose (CEL) for 4 weeks. The in vivo study demonstrated that some positive changes in the cecal metabolism resulting from the ingestion of a diet enriched only with FOS were completely or slightly suppressed by the dietary ET. In particular, the pH value (7.21 vs 7.36), short-chain fatty acid production (41.2 vs 30.0 μmol/100g BW), and β-glucuronidase activity (20.2 vs 15.7 μmol/h/g) in the cecum of rats fed with FOS were affected upon the addition of the ET extract. Dietary FOS caused higher metabolism of the tested ET strawberry extract in the gastrointestinal tract of rats. Moreover, the systemic effect of the supplements when consumed together showed undesired serum HDL-cholesterol decrease (0.78 vs 1.02 mmol/L in the treatment with FOS only).

Fermented wheat powder induces the antioxidant and detoxifying system in primary rat hepatocytes

Many plants exhibit antioxidant properties which may be useful in the prevention of oxidative stress reactions, such as those mediated by the formation of free radical species in different pathological situations. In recent years a number of studies have shown that whole grain products in particular have strong antioxidant activity. Primary cultures of rat hepatocytes were used to investigate whether and how a fermented powder of wheat (Lisosan G) is able to modulate antioxidant and detoxifying enzymes, and whether or not it can activate Nrf2 transcription factor or inhibit NF-kB activation. All of the antioxidant and detoxifying enzymes studied were significantly up-regulated by 0.7 mg/ml Lisosan G treatment. In particular,

NAD(P)H

quinone oxidoreductase and heme oxygenase-1 were induced, although to different degrees, at the transcriptional, protein and/or activity levels by the treatment. As for the Nrf2 transcription factor, a partial translocation of its protein from the cytosol to the nucleus after 1 h of Lisosan G treatment was revealed by immunoblotting. Lisosan G was also observed to decrease H2O2-induced toxicity Taken together, these results show that this powder of wheat is an effective inducer of ARE/Nrf2-regulated antioxidant and detoxifying genes and has the potential to inhibit the translocation of NF-kB into the nucleus.

Comparison of hydroxyl radical, peroxyl radical, and peroxynitrite scavenging capacity of extracts and active components from selected medicinal plants

The ability of 80% ethanol extracts from five medicinal plants, Aralia continentalis, Paeonia suffruticosa, Magnolia denudata, Anemarrhena asphodeloides, and Schizonepeta tenuifolia, to neutralize hydroxyl radical, peroxyl radical and peroxynitrite was examined using the total oxyradical scavenging capacity (TOSC) assay. Peroxyl radical was generated from thermal homolysis of 2,2'-azobis (2-methylpropionamidine) dihydrochloride (ABAP) ; hydroxyl radical by an iron-ascorbate Fenton reaction; peroxynitrite by spontaneous decomposition of 3-morpholinosydnonimine N-ethylcarbamide (SIN-1) . The oxidants generated react with α-keto-γ-methiolbutyric acid (KMBA) to yield ethylene, and the TOSC of the substances tested is quantified from their ability to inhibit ethylene formation. Extracts from P. suffruticosa, M. denudata,and S. tenuifolia were determined to be potent peroxyl radical scavenging agents with a specific TOSC (sTOSC) being at least six-fold greater than that of glutathione (GSH) . These three plants also showed sTOSCs toward peroxynitrite markedly greater than sTOSC of GSH, however, only P. suffruticosa revealed a significant hydroxyl radical scavenging capacity. Seven major active constituents isolated from P. suffruticosa, quercetin, (+) -catechin, methyl gallate, gallic acid, benzoic acid, benzoyl paeoniflorin and paeoniflorin, were determined for their antioxidant potential toward peroxynitrite, peroxyl and hydroxyl radicals. Quercetin, (+) -catechin, methyl gallate, and gallic acid exhibited sTOSCs 40~85 times greater than sTOSC of GSH. These four components also showed a peroxynitrite scavenging capacity higher than at least 10-fold of GSH. For antioxidant activity against hydroxyl radical, methyl gallate was greatest followed by gallic acid and quercetin. Further studies need to be conducted to substantiate the significance of scavenging a specific oxidant in the prevention of cellular injury and disease states caused by the reactive free radical species.

Hypoxia-induced lipid peroxidation in the brain during postnatal ontogenesis

Reactive oxygen species (ROS) are common products of the physiological metabolic reactions, which are associated with cell signaling and with the pathogenesis of various nervous disorders. The brain tissue has the high rate of oxidative metabolic activity, high concentration of polyunsaturated fatty acids in membrane lipids, presence of iron ions and low capacity of antioxidant enzymes, which makes the brain very susceptible to ROS action and lipid peroxidation formation. Membranes of brain cortex show a higher production of thiobarbituric acid-reactive substances (TBARS) in prooxidant system (ADP.Fe(3+)/NADPH) than membranes from the heart or kidney. Lipid peroxidation influences numerous cellular functions through membrane-bound receptors or enzymes. The rate of brain cortex Na(+),K(+)-ATPase inhibition correlates well with the increase of TBARS or conjugated dienes and with changes of membrane fluidity. The experimental model of short-term hypoxia (simulating an altitude of 9000 m for 30 min) shows remarkable increase in TBARS in four different parts of the rat brain (cortex, subcortical structures, cerebellum and medulla oblongata) during the postnatal development of Wistar rat of both sexes. Young rats and males are more sensitive to oxygen changes than adult rats and females, respectively. Under normoxia or hypobaric hypoxia both ontogenetic aspects and sex differences play a major role in establishing the activity of erythrocyte catalase, which is an important part of the antioxidant defense of the organism. Rats pretreated with L-carnitine (and its derivatives) have lower TBARS levels after the exposure to hypobaric hypoxia. The protective effect of L-carnitine is comparable with the effect of tocopherol, well-known reactive species scavenger. Moreover, the plasma lactate increases after a short-term hypobaric hypoxia and decreases in L-carnitine pretreated rats. Acute hypobaric hypoxia and/or L-carnitine-pretreatment modify serum but not brain lactate dehydrogenase activity. The obtained data seem to be important because the variations in oxygen tension represent specific signals of regulating the activity of many specific systems in the organism.

Molecular mechanisms of chemopreventive phytochemicals against gastroenterological cancer development

Cancer is one of the leading causes of death worldwide. Commonly used cancer treatments, including chemotherapy and radiation therapy, often have side effects and a complete cure is sometimes impossible. Therefore, prevention, suppression, and/or delaying the onset of the disease are important. The onset of gastroenterological cancers is closely associated with an individual’s lifestyle. Thus, changing lifestyle, specifically the consumption of fruits and vegetables, can help to protect against the development of gastroenterological cancers. In particular, naturally occurring bioactive compounds, including curcumin, resveratrol, isothiocyanates, (-)-epigallocatechin gallate and sulforaphane, are regarded as promising chemopreventive agents. Hence, regular consumption of these natural bioactive compounds found in foods can contribute to prevention, suppression, and/or delay of gastroenterological cancer development. In this review, we will summarize natural phytochemicals possessing potential antioxidant and/or anti-inflammatory and anti-carcinogenic activities, which are exerted by regulating or targeting specific molecules against gastroenterological cancers, including esophageal, gastric and colon cancers.

Xanthones from mangosteen extracts as natural chemopreventive agents: potential anticancer drugs

Despite decades of research, the treatment and management of malignant tumors still remain a formidable challenge for public health. New strategies for cancer treatment are being developed, and one of the most promising treatment strategies involves the application of chemopreventive agents. The search for novel and effective cancer chemopreventive agents has led to the identification of various naturally occurring compounds. Xanthones, from the pericarp, whole fruit, heartwood, and leaf of mangosteen (Garcinia mangostana Linn., GML), are known to possess a wide spectrum of pharmacologic properties, including antioxidant, anti- tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities. The potential chemopreventive and chemotherapeutic activities of xanthones have been demonstrated in different stages of carcinogenesis (initiation, promotion, and progression) and are known to control cell division and growth, apoptosis, inflammation, and metastasis. Multiple lines of evidence from numerous in vitro and in vivo studies have confirmed that xanthones inhibit proliferation of a wide range of human tumor cell types by modulating various targets and signaling transduction pathways. Here we provide a concise and comprehensive review of preclinical data and assess the observed anticancer effects of xanthones, supporting its remarkable potential as an anticancer agent.

Black tea polyphenols reverse epithelial-to-mesenchymal transition and suppress cancer invasion and proteases in human oral cancer cells

Epithelial-to-mesenchymal transition (EMT) in cancer cells is considered to be a prerequisite for acquiring invasive/migratory phenotype and subsequent metastasis. This study provides molecular evidence associated with the antimetastatic effect of black tea polyphenol extracts (BTE), which contain polyphenols including gallic acid, gallocatechin, catechin, epigallocatechin-3-gallate, epicatechin-3-gallate, and theaflavin 3,3'-digallate, in an an oral squamous cell culture system by showing a nearly complete inhibition on the invasion (p < 0.001) of SCC-4 cells via reduced activities of MMP-2 (p < 0.001) and u-PA (p < 0.001). Immunoblot was performed to find that BTE could induce up-regulation of epithelial markers such as E-cadherin and inhibit mesenchymal markers such as snail-1 and vimentin. BTE inhibited p-FAK and p-paxillin, indicating the anti-EMT effect of BTE in oral squamous cell carcinoma. BTE was evidenced by its inhibition of the tumor growth of SCC-4 cells via cancer cell xenografted nude mice mode. These results suggested that BTE could reduce invasion by reversing EMT in human oral cancer cells.

Anticlastogenic effect of β-glucan, extracted from Saccharomyces cerevisiae, on cultured cells exposed to ultraviolet radiation

β-glucan is an important polysaccharide due to its medicinal properties of stimulating the immune system and preventing chronic diseases such as cancer. The aim of the present study was to determine the anticlastogenic effect of β-glucan in cells exposed to ultraviolet radiation (UV). Chromosome aberration assay was performed in drug-metabolizing cells (HTC) and non drug-metabolizing cells (CHO-K1 and repair-deficient CHO-xrs5), using different treatment protocols. Continuous treatment (UV + β-glucan) was not effective in reducing the DNA damage only in CHO-xrs5 cells. However, the pre-treatment protocol (β-glucan before UV exposition) was effective in reducing DNA damage only in CHO-K1 cells. In post-treatment (β-glucan after UV exposition) did not show significative anticlastogenic effects, although there was a tendency toward prevention. The data suggest that β-glucan has more than one action mechanism, being capable of exerting desmutagenic as well as bio-antimutagenic action. The findings also suggest that the presence of the xenobiotic metabolizing system can reduce the chemopreventive capacity of β-glucan. Therefore, these results indicate that β-glucan from Saccharomyces cerevisiae can be used in the prevention and/or reduction of DNA damage.

Color compensation in nitrite-reduced meat batters incorporating paprika or tomato paste

BACKGROUND

Nitrite is a key ingredient the manufacture of meat products, forming a stable pink color characteristic of cured products, retarding the development of rancidity and off-odors and flavors during storage, and preventing microbial growth. The negative aspects of nitrite and the demands for healthy foods result in the need to reduce nitrite in cured meat products. Paprika or tomato has been employed as natural pigments in meat products. The objective of this work was to determine the effect of incorporating paprika powder or tomato paste on the texture, rancidity and instrumental and sensory color compensation in nitrite-reduced meat batters.

RESULTS

Addition of tomato paste improved moisture content, resulting in harder but less cohesive samples as compared to control and paprika-containing meat batters. Color characteristics of reduced nitrite samples obtained higher a* red coloration (8.9 for paprika and 7.7-8.0 for tomato paste), as compared to control samples (5.65). Instrumental color was low in control samples, with high values for tomato paste and paprika samples. Nonetheless, tomato paste used to compensate color in nitrite-reduced meat batters was ranked closer to the control sample in sensory evaluation.

CONCLUSION

Color characteristics-instrumental and sensory-in these kinds of meat products were enhanced by the addition of 2.5-3.0% of tomato paste, presenting results close to the non-reduced nitrite control. Similarly, antioxidant components of tomato paste or paprika reduced lipid oxidation. Nitrite reduction from 150 to 100 ppm could be achieved employing tomato paste as a natural pigment to improve color and texture.

Polyphenol content and modulatory activities of some tropical dietary plant extracts on the oxidant activities of neutrophils and myeloperoxidase

Young leaves of Manihot esculenta Crantz (Euphorbiaceae), Abelmoschus esculentus (Malvaceae), Hibiscus acetosella (Malvaceae) and Pteridium aquilinum (Dennstaedtiaceae) are currently consumed as green vegetables by peoples in sub-Saharan Africa, Latin America, Asia and their migrants living in Western Europe. Sub-Saharan peoples use Manihot, Abelmoschus and Hibiscus also in the folk medicine to alleviate fever and pain, in the treatment of conjunctivitis, rheumatism, hemorrhoid, abscesses, ... The present study investigates the effects of aqueous extracts of those plants on the production of reactive oxygen species (ROS) and the release of myeloperoxidase (MPO) by equine neutrophils activated with phorbol 12-myristate 13-acetate (PMA). The ROS production was measured by lucigenin-enhanced chemiluminescence (CL), and the release of total MPO by an ELISA method. The study also investigates the effect of the extracts on the activity of MPO by studying its nitration activity on tyrosine and by using a new technique called SIEFED (Specific Immunological Extraction Followed by Enzymatic Detection) that allows studying the direct interaction of compounds with the enzyme. In all experiments, the aqueous extracts of the plants developed concentration-dependent inhibitory effects. A moderate heat treatment did not significantly modify the inhibitory capacity of the extracts in comparison to not heated ones. Total polyphenol and flavonoid contents were determined with an HPLC-UV/DAD analysis and a spectroscopic method using Folin-Ciocalteu reagent. Some polyphenols with well-known antioxidant activities (caffeic acid, chlorogenic acid, hyperoside, rosmarinic acid and rutin) were found in the extracts and may partly explain the inhibitory activities observed. The role of those dietary and medicinal plants in the treatment of ROS-dependent inflammatory diseases could have new considerations for health.

Antioxidant and antiradical activities of Manihot esculenta Crantz (Euphorbiaceae) leaves and other selected tropical green vegetables investigated on lipoperoxidation and phorbol-12-myristate-13-acetate (PMA) activated monocytes

Abelmoschus esculentus (Malvaceae), Hibiscus acetosella (Malvaceae), Manihot esculenta Crantz (Euphorbiaceae) and Pteridium aquilinum (Dennstaedtiaceae) leaves are currently consumed as vegetables by migrants from sub-Saharan Africa living in Western Europe and by the people in the origin countries, where these plants are also used in the folk medicine. Manihot leaves are also eaten in Latin America and some Asian countries. This work investigated the capacity of aqueous extracts prepared from those vegetables to inhibit the peroxidation of a linoleic acid emulsion. Short chain, volatile C-compounds as markers of advanced lipid peroxidation were measured by gas chromatography by following the ethylene production. The generation of lipid hydroperoxides, was monitored by spectroscopy using N-N'-dimethyl-p-phenylene-diamine (DMPD). The formation of intermediate peroxyl, and other free radicals, at the initiation of the lipid peroxidation was investigated by electron spin resonance, using α-(4-pyridyl-1-oxide)-N-tert-butylnitrone as spin trap agent. The ability of the extracts to decrease the cellular production of reactive oxygen species (ROS) in "inflammation like" conditions was studied by fluorescence technique using 2',7'-dichlorofluorescine-diacetate as fluorogenic probe, in a cell model of human monocytes (HL-60 cells) activated with phorbol ester. Overall the extracts displayed efficient concentration-dependent inhibitory effects. Their total polyphenol and flavonoid content was determined by classic colorimetric methods. An HPLC-UV/DAD analysis has clearly identified the presence of some polyphenolic compounds, which explains at least partially the inhibitions observed in our models. The role of these plants in the folk medicine by sub-Saharan peoples as well as in the prevention of oxidative stress and ROS related diseases requires further consideration.

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

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

Antioxidant potential of chestnut (Castanea sativa L.) and almond (Prunus dulcis L.) by-products

The antioxidant properties of almond green husks (Cvs. Duro Italiano, Ferraduel, Ferranhês, Ferrastar and Orelha de Mula), chestnut skins and chestnut leaves (Cvs. Aveleira, Boa Ventura, Judia and Longal) were evaluated through several chemical and biochemical assays in order to provide a novel strategy to stimulate the application of waste products as new suppliers of useful bioactive compounds, namely antioxidants. All the assayed by-products revealed good antioxidant properties, with very low EC(50) values (lower than 380 μg/mL), particularly for lipid peroxidation inhibition (lower than 140 μg/mL). The total phenols and flavonoids contents were also determined. The correlation between these bioactive compounds and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, inhibition of β-carotene bleaching and inhibition of lipid peroxidation in pig brain tissue through formation of thiobarbituric acid reactive substances, was also obtained. Although, all the assayed by-products proved to have a high potential of application in new antioxidants formulations, chestnut skins and leaves demonstrated better results.

Antioxidant, free radical-scavenging activity and cytotoxicity of different solvent extracts and their phenolic constituents from the fruit hull of mangosteen (Garcinia mangostana)

Antioxidative, skin protective activities, and cytotoxicity of three extracts (water, methanol, and hexane) from the fruit hull of mangosteen (Garcinia mangostana Linn. (Guttiferae)) and their phenolic constituents such as alpha-mangostin, epicatechin, and tannin, were evaluated. The amounts of alpha-mangostin, total flavonoid, and total tannin were different among the three extracts, except those of total tannin in methanol and hexane extracts. For the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging, hydroxyl radical-scavenging, and inhibition of lipid peroxidation experiment, the water extract showed higher activity than the methanol extract and hexane extract. alpha-Mangostin, epicatechin, and tannin also revealed these antioxidant and free radical-scavenging activities. When added simultaneously with H(2)O(2) (200 microM) to keratinocyte cells, the water extract (50 microg/mL), epicatechin (200 microM), and tannin (200 microM) effectively protected cells from oxidative damage, but the methanol extract, hexane extract, and alpha-mangostin did not. The methanol extract and hexane extract exhibited moderate cytotoxicity, whereas alpha-mangostin showed strong cytotoxicity. The present study provides the evidence that Garcinia mangostana extracts, especially the G. mangostana water extract, act as antioxidants and cytoprotective agents against oxidative damage, which is at least partly due to its phenolic compounds in mangosteen.