Seeds often survive in the soil in a dormant state, but their persistence is endangered by micro-organisms that could feed on them. Seed–microbe interactions in the soil are, however, poorly understood. We used dormant caryopses of red rice to study the defence response induced by pronase, a mixture of proteases secreted by Streptomyces griseus, a non-pathogenic bacterium. Pronase was shown to activate the plant immune reaction, indicating that its activity was recognized as a potential microbial attack. The defence reaction included extracellular alkalinization and superoxide production, and the former was necessary to activate the latter, since buffering at pH 6 inhibited the oxidative burst. Alkalinization was sufficient to trigger the oxidative burst, as superoxide production increased when caryopses were incubated in buffered solutions of increasing pH without pronase. Release of proanthocyanidins was observed, with or without pronase. These diverse mechanisms are hypothesized to cooperate in reinforcing seed protection. Finally, time profiles of superoxide production by dormant and non-dormant red rice caryopses during imbibition did not support a relationship between extracellular superoxide and dormancy breaking or germination. Thus, the role of this reactive oxygen species in red rice imbibed caryopses appears to be essentially aimed at defence against attacks by challenging micro-organisms.

Several descriptive studies on the intake of polyphenols, mostly flavonoids, have been published, especially in Europe and the USA, but insufficient data are still available in Latin-American countries, where different types of foods are consumed and different dietary habits are observed. The goal of this cross-sectional study was to estimate dietary intakes of polyphenols, including grand total, total per classes and subclasses and individual compounds, and to identify their main food sources in Mexican women. The Mexican Teachers’ Cohort includes 115 315 female teachers, 25 years and older, from twelve states of Mexico, including urban and rural areas. Dietary data were collected in the period 2008–2011 using a validated FFQ, and individual polyphenol intake was estimated using food composition data from the Phenol-Explorer database. Median total polyphenol intake was the highest in Baja California (750 mg/d) and the lowest in Yucatan (536 mg/d). The main polyphenols consumed were phenolic acids (56·3–68·5 % total polyphenols), followed by flavonoids (28·8–40·9 %). Intake of other polyphenol subclasses (stilbenes, lignans and others) was insignificant. Coffee and fruits were the most important food sources of phenolic acids and flavonoids, respectively. Intake of a total of 287 different individual polyphenols could be estimated, of which forty-two were consumed in an amount ≥1 mg/d. The most largely consumed polyphenols were several caffeoylquinic acids (ranging from 20 and 460 mg/d), ferulic acid, hesperidin and proanthocyanidins. This study shows a large heterogeneity in intakes of individual polyphenols among Mexican women, but a moderate heterogeneity across Mexican states. Main food sources were also similar in the different states.

Plants containing condensed tannins (CT) may have potential to control gastrointestinal nematodes (GIN) of cattle. The aim was to investigate the anthelmintic activities of four flavan-3-ols, two galloyl derivatives and 14 purified CT fractions, and to define which structural features of CT determine the anti-parasitic effects against the main cattle nematodes. We used in vitro tests targeting L1 larvae (feeding inhibition assay) and adults (motility assay) of Ostertagia ostertagi and Cooperia oncophora. In the larval feeding inhibition assay, O. ostertagi L1 were significantly more susceptible to all CT fractions than C. oncophora L1. The mean degree of polymerization of CT (i.e. average size) was the most important structural parameter: large CT reduced larval feeding more than small CT. The flavan-3-ols of prodelphinidin (PD)-type tannins had a stronger negative influence on parasite activity than the stereochemistry, i.e. cis- vs trans-configurations, or the presence of a gallate group. In contrast, for C. oncophora high reductions in the motility of larvae and adult worms were strongly related with a higher percentage of PDs within the CT fractions while there was no effect of size. Overall, the size and the percentage of PDs within CT seemed to be the most important parameters that influence anti-parasitic activity.

Epidemiological studies suggest health-protective effects of flavan-3-ols and their derived compounds on chronic diseases. The present study aimed to estimate dietary flavan-3-ol, proanthocyanidin (PA) and theaflavin intakes, their food sources and potential determinants in the European Prospective Investigation into Cancer and Nutrition (EPIC) calibration cohort. Dietary data were collected using a standardised 24 h dietary recall software administered to 36 037 subjects aged 35–74 years. Dietary data were linked with a flavanoid food composition database compiled from the latest US Department of Agriculture and Phenol-Explorer databases and expanded to include recipes, estimations and retention factors. Total flavan-3-ol intake was the highest in UK Health-conscious men (453·6 mg/d) and women of UK General population (377·6 mg/d), while the intake was the lowest in Greece (men: 160·5 mg/d; women: 124·8 mg/d). Monomer intake was the highest in UK General population (men: 213·5 mg/d; women: 178·6 mg/d) and the lowest in Greece (men: 26·6 mg/d in men; women: 20·7 mg/d). Theaflavin intake was the highest in UK General population (men: 29·3 mg/d; women: 25·3 mg/d) and close to zero in Greece and Spain. PA intake was the highest in Asturias (men: 455·2 mg/d) and San Sebastian (women: 253 mg/d), while being the lowest in Greece (men: 134·6 mg/d; women: 101·0 mg/d). Except for the UK, non-citrus fruits (apples/pears) were the highest contributors to the total flavan-3-ol intake. Tea was the main contributor of total flavan-3-ols in the UK. Flavan-3-ol, PA and theaflavin intakes were significantly different among all assessed groups. This study showed heterogeneity in flavan-3-ol, PA and theaflavin intake throughout the EPIC countries.

The present study aims to determine the effects of grape seed proanthocyanidin extract (GSPE) on brown adipose tissue (BAT) mitochondrial function in a state of obesity induced by diet. Wistar male rats were fed with a cafeteria diet (Cd) for 4 months; during the last 21 d, two groups were treated with doses of 25 and 50 mg GSPE/kg body weight. In the BAT, enzymatic activities of citrate synthase, cytochrome c oxidase (COX) and ATPase were determined and gene expression was analysed by real-time PCR. The mitochondrial function of BAT was determined in fresh mitochondria by high-resolution respirometry using both pyruvate and carnitine–palmitoyl-CoA as substrates. The results show that the Cd causes an important decrease in the gene expression of sirtuin 1, nuclear respiratory factor 1, isocitrate dehydrogenase 3γ and COX5α and, what is more telling, decreases the levels of mitochondrial respiration both with pyruvate and canitine–palmitoyl-CoA. Most of these parameters, which are indicative of mitochondrial dysfunction due to diet-induced obesity, are improved by chronic supplementation of GSPE. The beneficial effects caused by the administration of GSPE are exhibited as a protection against weight gain, in spite of the Cd the rats were fed. These data indicate that chronic consumption of a moderate dose of GSPE can correct an energy imbalance in a situation of diet-induced obesity, thereby improving the mitochondrial function and thermogenic capacity of the BAT.

Plant phenolic compounds are diverse in structure but are characterised by hydroxylated aromatic rings (e.g. flavan-3-ols). They are categorised as secondary metabolites, and their function in plants is often poorly understood. Many plant phenolic compounds are polymerised into larger molecules such as the proanthocyanidins (PA; condensed tannins) and lignins. Only the lignins, PA, oestrogenic compounds and hydrolysable tannins will be considered here. Lignins slow the physical and microbial degradation of ingested feed, because of resilient covalent bonding with hemicellulose and cellulose, rather than any direct effects on the rumen per se. The PA are prevalent in browse and are expressed in the foliage of some legumes (e.g. Lotus spp.), but rarely in grasses. They reduce the nutritive value of poor-quality diets, but can also have substantial benefits for ruminant productivity and health when improved temperate forages are fed. Beneficial effects are dependent on the chemical and physical structure, and concentration of the PA in the diet, but they have been shown to improve live-weight gain, milk yield and protein concentration, and ovulation rate. They prevent bloat in cattle, reduce gastrointestinal nematode numbers, flystrike and CILt production. Some phenolic compounds (e.g. coumestans) cause temporary infertility, whilst those produced by Fusarium fungi found in pasture, silage or stored grains can cause permanent infertility. The HT may be toxic because products of their metabolism can cause liver damage and other metabolic disorders.

Tanniferous forage plants can have beneficial effects on ruminant productivity and health (improved protein supply, bloat safety and antiparasitic properties). However, condensed tannins can also lower palatability, voluntary feed intake and digestibility. The aim of our interdisciplinary project was to generate basic knowledge on plant management, feed palatability and the antiparasitic properties of tanniferous forage plants for their practical application in agronomy, focusing on their usefulness in controlling gastrointestinal nematodes in organic farming. We found that Onobrychis viciifolia (sainfoin), Lotus corniculatus (birdsfoot trefoil) and Cichorium intybus (chicory) were suitable for cultivation under the given temperate climatic conditions, whereas Lotus pedunculatus (big trefoil) was soon outcompeted by unsown species. Growing the tanniferous plant species in a mixture with Festuca pratensis (meadow fescue) rather than in a monoculture had the advantage of increasing total dry matter (DM) yield (especially in the case of tanniferous legumes) and of reducing the DM proportions of unsown species. However, due to dilution by non-tanniferous F. pratensis, the tannin concentrations of mixtures were clearly lower and the seasonal fluctuations in tannin concentrations greater than that of monocultures. Across species, tannin concentrations were highest for O. viciifolia, followed by L. corniculatus and very low for C. intybus. Palatability of all tanniferous forages was comparable to that of a ryegrass/clover mixture when fed as dried forage and, when offered as silage, palatability of O. viciifolia was clearly superior to that of the respective ryegrass/clover control. Administration of dried or ensiled O. viciifolia reduced parasite egg counts in feces of lambs co-infected with the gastrointestinal nematode species Haemonchus contortus and Cooperia curticei. We conclude that O. viciifolia is the most promising among the tested tanniferous forage plant species due to its suitability for cultivation, its high tannin concentration, its high palatability and its antiparasitic activity even in dried or ensiled form.

Proanthocyanidins (condensed tannins; PA) purified from the leaves of forage legumes Trifolium arvense, Lotus pedunculatus, Lotus corniculatus, Dorycnium rectum, Coronilla varia, Onobrychis viciifolia, or Hedysarum coronarium, were added to soluble lucerne (Medicago sativa) leaf protein and incubated with strained rumen fluid in vitro. Fractions were collected and frozen immediately. Denatured proteins were fractionated by sodium dodecylsulphate–polyacrylamide gel electrophoresis (SDS–PAGE), stained, and relative levels were quantified by densitometry. In the absence of PA the large subunit (LSU) of ribulose bisphosphate carboxylase (EC 4. 1. 1. 39) was susceptible to proteolysis by rumen microflora but the small subunit (SSU) resisted breakdown. PA purified from Onobrychis was added to soluble leaf protein, at PA: protein ratios between 1:1 and 1:20. The rate of proteolysis of LSU1 was significantly reduced at PA: protein ratios of 1:2 and 1:1 (P < 0.001) and the rate of digestion was reduced by between 3- and 21-fold. In separate experiments PA isolated from the range of species described was added to rumen fluid to give PA: protein ratios of 1: 5. The addition of PA significantly reduced the rate of proteolysis of LSU, when compared with PA-free control. There were only small differences between PA from different species. The inhibitory effect of PA may have been due to PA binding to the dietary protein or to the rumen proteases, interfering with the action of proteases on susceptible sites within the substrate.

Cotyledons and hulls were prepared from twelve varieties of field beans (Vicia faba L.). Adult cockerels were tube-fed either beans, cotyledons or hull diets containing high or low levels of protein. Metabolizable energy coefficients and starch digestibility coefficients were determined for beans, cotyledons and hull diets. Lipid digestibility coefficients from hull diets were also determined. When cotyledons were fed there were no significant differences in the way in which adult cockerels metabolized energy or digested starch from the proanthocyanidin-free and proanthocyanidin-rich varieties (0·780, 0·908, 0·775 and 0·918 respectively). When beans were fed, however, both energy metabolizability and starch digestibility decreased due to the presence of hulls, with proanthocyanidin-rich hulls decreasing values the most to 0·660 and 0·819 respectively, and proanthocyanidin-free hulls decreasing values to a lesser extent to 0·709 and 0·886 respectively. Diets composed of proanthocyanidin-rich hulls depressed metabolizable energy and maize starch digestibility. Their effect on maize starch digestibility, however, was considerably less than that on bean starch. Lipid digestibility was enhanced by proanthocyanidins but only when the protein content of the diet was high. There was a significant correlation (P < 0·05) between the vanillin and anthocyanidin formation methods for the estimation of proanthocyanidins (r 0·779). There was also a highly significant regression of bean starch digestibility v. proanthocyanidin content of coloured-flowered bean hulls (P < 0·001). The regression of maize starch digestibility v. hull proanthocyanidins was also significant at P < 0·005.