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PubMed2004

Diet-derived phenols in plasma and tissues and their implications for health.

This paper seeks to catalyse a reappraisal of the nature, fate and biological significance in humans of phenols, polyphenols and tannins (PPT) consumed in normal diets, and in particular questions the primacy of PPT radical-scavenging mechanisms for the supposed health benefits of diets rich in fruits and vegetables. PPT are classified by structure and function. Arguments are presented to show that cinnamates and derived polyphenols make significantly larger contributions to the total PPT intake than the flavonols and flavones upon which the vast majority of attention has been focussed previously. Daily intakes of total PPT may range from less than 100 mg to in excess of 2 g, and the critical importance of coffee and black tea as the major dietary sources is shown. Only some 5% of the dietary PPT is absorbed in the duodenum, and of this only some 5%, mainly flavanols, reaches the plasma unchanged, the balance being mammalian conjugates. Over 95% of the intake passes to the colon and is fermented by the gut microflora. A fraction of the resulting microbial metabolites is absorbed and appears in the plasma primarily as mammalian conjugates. Even following high intakes of PPT, the plasma metabolites collectively make a very small (less than 5%) and transient contribution to the total concentration of redox active substances in plasma. This explains the failure of most studies that sought to detect an increase in plasma antioxidant power after consuming a PPT-rich meal or supplement. The powerfully antioxidant PPT aglycones, much used in in vitro studies, do not reach the plasma. The redox potential of those unchanged PPT and PPT metabolites that reach the plasma enables them to scavenge damaging radicals, but the endogenous plasma antioxidants, especially ascorbate, are required for disposal of the resultant phenoxyl radicals. Black tea and coffee, the major sources of PPT, are poor sources of ascorbate. It is suggested that if diets rich in fruits and vegetables are health-promoting, and if these effects are due to PPT, then alternatives to radical-scavenging mechanisms must be sought. Evidence is presented to show that some mammalian metabolites of PPT may indeed be able to protect the vascular endothelium and that diets rich in PPT may in humans at normal dietary levels have the ability to protect against Type II diabetes and the metabolic syndrome through effects on glucose absorption and associated hormones. Such effects are recommended for further investigation.

Antioxidants↗
PubMed2005

Casuarinin from the bark of Terminalia arjuna induces apoptosis and cell cycle arrest in human breast adenocarcinoma MCF-7 cells.

Casuarinin, a hydrolyzable tannin isolated from the bark of Terminalia arjuna L. (Combretaceae), was investigated for its antiproliferative activity in human breast adenocarcinoma MCF-7 cells. The results showed that casuarinin inhibited the proliferation of MCF-7 by blocking cell cycle progression in the G0/G1 phase and inducing apoptosis. An enzyme-linked immunosorbent assay showed that casuarinin increased the expression of p21/WAF1 concomitantly as the MCF-7 cells underwent G0/G1 arrest. An enhancement in Fas/APO-1 and its two forms of ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), might be responsible for the apoptotic effect induced by casuarinin. Our study reports here for the first time that the induction of p21/WAF1 and the activity of Fas/Fas ligand apoptotic system may participate in the antiproliferative activity of casuarinin in MCF-7 cells.

Adenocarcinoma↗
PubMed2006

Plant phenolics inhibit neutrophil elastase.

Human neutrophil elastase (HNE) is a serine protease, which is present in its active form in inflamed tissue as well as in psoriatic lesions. In extension of our research on natural compounds as inhibitors of HNE or of its release, several phenolics of different size were tested. The ellagitannins agrimoniin and pedunculagin were the most potent direct HNE inhibitors (IC (50) = 0.9 and 2.8 microM, respectively). Ligand docking calculations provided evidence that inhibition may occur in an unspecific manner. Agrimoniin also showed anti-proliferative effects in the ATP assay (IC (50) = 3.2 microM), suggesting that this type of tannin could have beneficial effects in the treatment of diseases such as psoriasis. Tests with other phenolics combined with ligand docking experiments revealed that, besides the presence of ORTHO-dihydroxy groups, a specific lipophilic shape is necessary for an inhibitory activity. The phenolic genistein deserves special interest as an inhibitor of elastase release because its effect was remarkably potent (IC (50) = 0.6 microM).

Catechin↗
PubMed2001

Differential long-term effects of tannic acid on adenyl cyclase activity and lipolysis in rat adipocytes.

Plants elaborate a variety of secondary metabolites such as hydrolysable tannins which are relatively abundant in fruits, vegetables and beverages in the human diet. We have studied the in vivo long-term effect consumption of tannic acid-supplemented drinking water (0.05%, w/v) on the rat adipocyte adenyl cyclase system and on lipolysis. We found that 14-day tannic acid supplementation did not significantly affect either body growth or food consumption, while fat pads weight was higher than that of the control, although the difference was not significant. On the other hand, tannic acid supplementation decreased both basal and isoproterenol-stimulated lipolysis significantly whereas cyclic AMP production as well as adenyl cyclase activity increased significantly. These results are at a first glance contradictory as cyclic AMP accumulation and lipolysis are positively correlated in rat adipocytes. They suggest at least that the tannic acid diet led to an inhibition of cyclic AMP-dependent protein kinase activity followed by a decrease in lipolysis in rat adipocytes, and to an increased activity of the type VI adenyl cyclase subunit of rat fat cells. This subunit is known to be negatively regulated under phosphorylation by cyclic AMP-dependent protein kinase. More in-depth studies are required to examine whether tannic acid could at least modify the expression of the catalytic subunit of adenyl cyclase, G-proteins and cyclic AMP-dependent protein kinase and/or alter their activities.

Adenylyl Cyclases↗
PubMed2003

Chemical composition and nutritive value of kapok seed meal for broiler chickens.

1. Mechanically extracted kapok (Ceiba pentandra) seed meal (KSM) contained 324 g crude protein, 97 g ether extract, 289 g fibre, 94 g ash, 128 g available carbohydrates, 3-8 g calcium, 11 g phosphorus, 10.4 g cyclopropenoid fatty acids and 15 g tannins per kg. 2. In a 4 x 2 factorial experiment, KSM was incorporated in broiler starter and finisher feeds at 0, 30, 60 and 90 g/kg, replacing sunflower meal (SFM) w/w; without and with multi-enzyme supplementation. 3. No significant differences were noticed between treatments in body weight gain, feed consumption, feed conversion efficiency, mortality or carcase yields. 4. Multi-enzyme (amylase, endoxylanase, hemicellulase, beta-glucanase, pectinase, phytase and protease) supplementation did not improve the growth performance of broilers fed on the KSM diets.

Animal Feed↗
PubMed1999

Optimum inclusion of field peas, faba beans, chick peas and sweet lupins in poultry diets. I. Chemical composition and layer experiments.

1. Experiments were undertaken to determine the chemical composition and apparent metabolisable energy (AME) of field peas, faba beans, sweet lupins and chick peas and the production of hens when each was included in nutritionally similar diets at 250 g/kg in 2 experiments. 2. Amino acid composition, crude protein and AME agreed well with previously published measurements. Detailed analysis of the non-starch polysaccharides (NSPs) showed that sweet lupins were much higher than the other grain legumes in the soluble NSPs and that the NSPs were particularly high in arabinose. The condensed tannin content was highest in field peas followed by faba beans. 3. In the 1st layer experiment over 40 weeks, hen-day egg production was lowest on the faba bean-based diet and egg weight and egg mass were also lowest. Relative viscosity of digesta in the small intestine of hens fed on the sweet lupin-based diet was highest, followed by that of hens fed on field peas. Enlargement of the pancreas was observed in hens consuming chick peas. 4. In experiment 2, in which only sweet lupins and faba beans were used, steam or cold pelleting showed few effects, nor did dehulling of faba beans but egg weight was lower when diets were steam pelleted. Daily food intake was 5.7 g/bird lower on the steam than cold pelleted diets and food conversion ratio tended to be improved (P=0.082). 5. It was concluded that field peas could support good production at 250 g/kg of layer diet. Although chick peas and sweet lupins supported good performance, there was concern about the increased weight of the pancreas and high gut viscosity respectively. Faba beans showed similar hen-d egg production in the 2nd experiment to that of sweet lupins but egg weight tended to be about 0.8 g lower than when on the sweet lupin-based diets.

Amino Acids↗
PubMed2006

In vivo anthelmintic activity of Dorycnium rectum and grape seed extract against Ostertagia (Teladorsagia) circumcincta and Trichostrongylus colubriformis in sheep.

AIM: To assess the in vivo anthelmintic activity of condensed tannins (CT) in the forage species Dorycnium rectum and Medicago sativa, and in an extract from grape (Vitus vinifera) seeds (GSE), against two species of parasite, Teladorsagia (Ostertagia) circumcincta and Trichostrongylus colubriformis, at different stages of their life cycle, in sheep that were parasite-naïve or previously exposed to nematodes. METHODS: In Trial 1, a factorial treatment structure was used to compare faecal nematode egg counts (FEC) and worm burdens in 40 weaned Romney lambs fed either the CT-containing forage D. rectum (12% dry matter; DM) or M. sativa (lucerne; 0.2% DM). Twenty naïve and 20 previously-exposed lambs were drenched free of parasites then reinfected with known species and numbers of parasites, and housed in pens indoors on a diet of lucerne pellets and chaffed hay. Groups of lambs (n=5 lambs per group) were fed one of the forages over one of two time periods within the parasite's life cycle. Six to nine days after the last feeding of fresh forages, faecal samples were collected for FEC, and all lambs were slaughtered and worm counts conducted. In Trial 2, 12 Suffolk x Romney lambs were surgically implanted with an abomasal cannula and then housed indoors in metabolism crates. After infection with parasites, six lambs were infused continuously over a 14-day period with a commercially available CT GSE (96% DM, made up to 34 g/L in water); the remaining lambs were infused with water. During infusion, samples were collected for egg hatch and larval development assays. After infusion, samples were collected for FEC, and all lambs were slaughtered and worm counts conducted. RESULTS: In Trial 1, there was a significant (p<0.001) difference in burdens of O. circumcincta between naïve lambs and those previously exposed to parasites, but no other differences were recorded. In Trial 2, lambs infused with GSE had significantly (p<0.05) fewer T. colubriformis at slaughter and significantly (p<0.001) fewer eggs hatched in the egg hatch assay (EHA) than for lambs infused with water. Overall, the differences attributable to GSE were small in magnitude, being an 11% drop in egg hatch, and an 18% drop in numbers of adult T. colubriformis after 14 days of continuous infusion. No other differences were recorded. CONCLUSION: The results indicate that the in vivo anthelmintic activity of these CT sources is, at best, modest and is unlikely to be of any practical value. Further, these data emphasise that in vitro activity is an unreliable indicator of in vivo efficacy for CT-containing forages and extracts.

Animals↗
PubMed1981

Carcinogens occurring naturally in food.

Carcinogens naturally occurring in food include metabolites of microorganisms which infect plants during harvesting and storage; products of the normal metabolism of plants and products of chemical changes occurring during processing, preservation, preparation or which are picked up from the environment, including contaminated water or soil. Some examples of these types of carcinogens are: fungal metabolites such as aflatoxins in peanuts stored under improper conditions; safrol from the oil of various plants; tannin in tea, grain and grapes; and polycyclic hydrocarbons including benzo (a) pyrene formed by smoking meat and fish. Epidemiological studies indicate that there is a high incidence of gastric cancer in the areas of the world where smoked fish are common in diets. Vitamin A may play a role in preventing the carcinogenic action of polycyclic hydrocarbons.

Animals↗
PubMed2001

NMR and simulated annealing investigations of bradykinin in presence of polyphenols.

Epidemiological studies have shown that the incidence of some cardiovascular degenerative diseases appears to be lower in populations with regular but moderate drinking of red wine rich in polyphenols. One of the most important properties of polyphenols is to form complexes with proteins. The linear nonapeptide hormone bradykinin (H-Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-Pro7-Phe8-Arg9-OH) is involved in a variety of physiological processes such as the cardiovascular processes. Thus, the goal of this work was to study the effects of tannins on the peptide structure by NMR investigations and molecular modeling. The results of these investigations show that in the presence of catechin, the peptide conformation is not affected and is in a random coil structure. On the contrary, the peptide structure is modified by the addition of dimeric proanthocyanidin B3 (catechin 4alpha-->8 catechin). The dimer leads to the formation of a large flexible turn between the 6-9 residues. Thus, the biological activities of bradykinin in the presence of polyphenols could be affected.

Anthocyanins↗
PubMed2003

Chemical composition of certain tribal pulses in South India.

Raw seeds of tribal pulses Atylosia scarabaeoides, Canavalia gladiata, Lablab purpureus var. lignosus, Neonotonia wightii var. coimbatorensis, Rhynchosia filipes, Vigna trilobata and Vigna unguiculata subsp. unguiculata were investigated for their proximate composition, minerals, vitamins (niacin and ascorbic acid) and certain anti-nutritional substances. The seeds of L. purpureus var. lignosus and V. trilobata had a higher content of crude protein than the commonly consumed Indian pulses. The seeds were found to be a rich source of minerals like potassium when compared with recommended dietary allowance values. The total free phenolics, tannins, 3,4-dihydroxyphenylalanine and hydrogen cyanide were also analysed.

Developing Countries↗
PubMedDate not supplied

Statistical model for predicting non-heme iron bioavailability from vegetarian meals.

Availability of non-heme iron has been extensively discussed when meals comprise heme as well as non-heme iron, but seldom so for exclusively vegetarian meals. The present study aimed to develop a statistical model for predicting non-heme iron availability from a composite vegetarian meal. Radioisotopic measurements of in vitro iron dialyzability of 208 out of 274 meals representing vegetarian diets from Asia, Africa, Europe and Latin America and the meal contents of iron, zinc, copper, ascorbic acid, beta-carotene, riboflavin, thiamin, folic acid, tannic acid, fiber and degraded phytate forms (IP6-IP1) were used for development of the model. A multiple regression model weighted for calorie contents was developed for the percentage iron dialyzability with the possible predictors as meal contents along with plausible interaction terms. The model was validated with in vitro iron dialyzability of 66 meals and in vivo iron absorption in five ileostomized adults. Application of the model was demonstrated using data on the daily dietary intake of 215 young adults whose hemoglobin levels were estimated twice in 3 weeks. Weighted multiple regression model was: ln(% Fe dialyzability)=1.340-0.259xln(IP2 [mg])+0.188xln(IP3 [mg])-0.278xln(IP5 [mg])+0.0912xln(ascorbic acid [mg])+0.06693xln(tannins [mg])+0.09552xln(beta-carotene [microg])+0.137xln(hemicellulose [g]) (P<0.01, R2=0.51). Good agreement was seen between observed and predicted dialyzability (r=0.90) and human absorption (r=0.89). The model would be useful to estimate bioavailable iron intakes of vegetarian populations and to identify at-risk individuals.

Adult↗
PubMed1980

The biochemistry and technology of tea manufacture.

This review surveys tea-production technology, chemistry of raw and manufactured tea as well as tea tasting appraisal and chemical analysis of manufactured tea. The paper describes the healthful properties of tea, gives general information on the tea plant and manufactured tea, and presents classification of teas as related to the processing of black green, yellow, and red tea, green pressed tea as well as instant tea and tea dyes. The paper discusses the chemical composition of raw and manufactured tea as well as approaches to the evaluation of tea quality--tea tasting appraisal and chemical analysis. The paper is supplied with the conclusions and references. The section on the healthful properties of tea discusses various aspects of catechin effects--vitamin P, antimicrobial, antioxidative and radioprotective effects. Also described are favorable effects of tea alkaloids--caffeine, theobromine, theophylline that dilatate cerebral vessels and alleviate headaches. The section on the production of different teas (black, green, yellow, red, instant teas, and tea dyes) considers technological methods and biochemical bases of various types of tea manufacture. The role of tea leaf enzymes in the oxidative processes determining the tea quality is discussed in detail. This section also describes the contribution of thermochemical processes into the formation of tea flavor. The compounds dictating tea taste and aroma are discussed, particularly tannins and catechins, volatile oils, nitrogen compounds, and some other substances.

Alkaloids↗
PubMed1984

Technology of removal of unwanted components of dry beans.

Dry beans are one of the inexpensive sources of reasonable quality proteins, carbohydrates, vitamins, minerals, and fiber. Their underutilization has been attributed to the presence of several factors, such as proteinase inhibitors, flatus factors, tannins, phytates, phytohemagglutinins, and the beany flavor. Removal of these unwanted components promises improved utilization of dry beans for human food purposes. The current methodology of removing these factors includes several food processing techniques such as soaking, dry and moist heat treatment, filtration, germination, and fermentation. The commercial feasibility of these processes will be discussed. The current lack of knowledge about deleterious effects of the residual components (remaining after processing) will be addressed and the needs for the future will be discussed.

Chymotrypsin↗
PubMed1988

Natural astringency in foodstuffs--a molecular interpretation.

The structures of plant polyphenols (vegetable tannins) are briefly reviewed. Their interactions with proteins, polysaccharides, and the alkaloid caffeine are discussed at the molecular level, and these fundamental properties are related to the quality of astringency that polyphenols possess. The various ways in which astringency may be modified and ultimately lost are outlined in relation to the aging of red wines, the formation of nonbiological hazes in beers and lagers, and the ripening of fruit.

Astringents↗
PubMed2000

Preparative binding of Coomassie brilliant blue to bovine serum.

Laboratory scale preparation of bovine serum albumin (BSA) stained with Coomassie brilliant blue (CBB) at alkaline pH is first described. Physical-chemical analyses of CBB-BSA showed that the unprotonated (anion) CBB dye binds tightly to BSA in buffered media of pH 8.2. Characteristic differences in spectra lambda(max) and molar absorptivities were found for the free anion CBB dye versus the CBB-BSA complex. Binding studies with low versus high dye/protein concentration ratios at alkaline pH gave values for n, binding site numbers, and K, intrinsic binding coefficient, consistent with those reported in analytical studies under acidic pH, but higher than values for neutral pH. Comparative analyses of Beer's law plots for the alkaline CBB-BSA complex under different experimental conditions showed its high stability toward various interferences, such as pH, strong detergents, temperature, light, prolonged storage, as well as high affinity for tannins. The hydrophobic nature of the CBB-BSA association at alkaline pH was tested.

Animals↗
PubMed2006

Study of the chemical interaction between barks and heavy metal cations in the sorption process.

The chemical mechanism displayed in the sorption of heavy metal cations on barks was discussed through a modelling study of adsorption in relation to the nature of the ligand borne by the chemical components of the bark sorbent. The adsorption isotherms of five heavy metal cations (Cr3 +, Cu2 +, Ni2 +, Pb2 +, Zn2+) on five species of barks (Sweet chestnut, Oak, Douglas fir, Norway spruce, Scots pine species) were studied. The experimental data fitted well the Langmuir model, which allowed the expression of the mathematical parameters (qmax, maximum binding capacity; b, affinity). The qmax values increased conversely to the b values. The correlation of these mathematical values (qmax and b) with the analysis of the chemical composition of barks led us to note that Cu2 + interacts preferentially with phenolic groups present in lignins and tannins and, opposite in, Pb2 + with the carboxylic acid groups in polysaccharides. These observations were explained (i) quantitatively by the amount of different types of sites and (ii) qualitatively, by the physicochemical characteristics of cations, the nature and the tridimensional structure of adsorption sites. Finally, the results allowed to define the nature of the chemical interaction (monodentate or multidentate complex) between each specified chemical component of barks and each kind of heavy metal cations.

Adsorption↗
PubMed2000

The chemical composition of Phyllanthus discoideus and its effect on the ruminal ammonia and volatile fatty acid concentration when fed to west African dwarf sheep.

The feeding value of Phyllanthus discoideus (also called Margaritaria discoidea) leaves was evaluated using eight two-year-old West African Dwarf sheep fed natural grass hay. Four of the animals were fistulated ruminally and used for ammonia and volatile fatty acid determination in the fluid. Dried leaves of Phyllanthus discoideus were offered at two levels (25% and 50% of DMI, diets D25% and D50%, respectively) as supplements to the basal hay diet. The CP content of the control, D25% and D50% diets were 11.5, 12.6 and 13.6%, respectively, and their digestible energy amounted to 58.2, 61.1 and 56.9%, respectively. Rumen liquor was sampled one hour before and one, three and five hours after the morning feeding. Sheep fed the control diet had a higher ruminal ammonia concentration than those fed diet D25%. Similarly, ruminal ammonia concentration was higher in sheep fed the control diet than those fed the diet D50%. Five hours after feeding the ruminal ammonia concentration was significantly lower than one hour after feeding. The VFA concentrations in rumen fluid of sheep fed the control diet was inferior to those fed diets D25% and D50%. Sheep fed diet D50% showed significantly higher VFA concentrations than those fed diet D25%. Digestibility of organic matter and digestible energy did not show any significant difference. However, a marginal increase in organic matter digestibility of 3.5% was observed in diet D25% compared with the control diet. There was no significant difference in the N-digestibility in sheep fed the control, D25% and D50% diets. Nevertheless, a marginal improvement in N-digestibility (1.5%) and N-retention (2.7%) was observed with the highest level of Phyllanthus discoideus (D50%). In conclusion, Phyllanthus discoideus appears as a particularly valuable feedstuff because it contains low levels of condensed tannins (12.8 g/kg), high CP content (156 g/kg) and a relatively high GE content (19.3 kJ/g DM). Although the improvement in N-digestibility and N-retention were only marginal the feeding of Phyllanthus discoideus could be justified under extreme shortage of feed resources during dry season. It should also be mentioned that a much more pronounced effect by supplementation with Phyllanthus discoideus could be expected when poor quality grass hay prevalent in West Africa during the dry season is fed. Phyllanthus discoideus could serve as a supplement to poor quality grass at 25% to 50% of supplementation.

Ammonia↗
PubMed2001

Micronutrient composition and nutritional importance of gathered vegetables in Vietnam.

This article presents the nutrient composition and nutritional contribution of naturally occurring vegetables (NOV) in four villages in Vietnam. The frequency of consumption and quantities eaten were evaluated within the overall diet of 101 and 110 women in the Mekong Delta (flood period and rainy season, respectively) and of 103 women in the Central Highlands (rainy season). The concentrations of Ca, Fe and Zn were analysed in 28 species, and presence of tannins and phytic acid in 19 species. Provitamin carotenoids were determined in 11 species. Over 90% of the women consumed NOV, and they contributed 43, 72 and 75% (Central Highlands, Mekong rainy and Mekong flood period, respectively) of the total quantities of vegetables eaten. Aquatic species such as lpomoea aquatica and Limnocharis flava, and terrestrial vegetables such as Schismattoglottis calyptrata, were among the most commonly consumed vegetables. They were eaten in mean daily quantities exceeding 50 g and had high concentrations of Ca, Fe and beta-carotene. Other major aquatic vegetables included the stems of Eleocharis sp., Nelumbo nucifera and Nymphea lotus, all of which were used as salad vegetables and had relatively low nutrient density. The problems of assessing the current role of NOV due to lack of data on intakes in the context of the overall diets, as well as data on their composition, are addressed.

Adult↗