diferulic-acid and ferulic-acid

Advanced breeding lines made from the cross between the black and white rice as parents were collected to evaluate phenolic levels and antioxidant properties. No free phenolic acid was found in the soluble fraction, while p-coumaric acid, ferulic acid, isoferulic acid and vanillic acid were identified in insoluble bound fractions. Of noteworthy, is isoferulic acid which has rarely been reported to occur in cereal grains. Phenolic dehydrodimers were only observed in the insoluble bound fractions, which mainly consisted of 8-5'-coupled diferulic acids and 5-5'-coupled diferulic acids. Cyanidin 3-glucoside, peonidin 3-glucoside and cyanidin occurred in black and some light-purple rice samples. The breeding line YF53 has the highest total phenolic content (23.3mg ferulic acid equiv./g), total anthocyanin content (2.07 mg cyanidin-3-glu equiv./g), and antioxidant activities. The results indicate that it is possible to develop advanced breeding lines for improvement of the phenolic profiles and antioxidant capacity with high yield.

Topics: Anthocyanins; Antioxidants; Coumaric Acids; Edible Grain; Glucosides; Hydroxybenzoates; Oryza; Plant Extracts; Propionates; Vanillic Acid

In plants belonging to the order of Caryophyllales, pectic neutral side chains can be substituted with ferulic acid. The ability of ferulic acid to form intra- and/or intermolecular polysaccharide cross-links by dimerization was shown by the isolation and characterization of diferulic acid oligosaccharides from monocotyledonous plants. In this study, two diferulic acid oligosaccharides were isolated from the enzymatic hydrolyzate of seeds of the dicotyledonous pseudocereal quinoa by gel permeation chromatography and preparative HPLC and unambiguously identified by LC-MS(2) and 1D/2D NMR spectroscopy. The isolated oligosaccharides are comprised of 5-5- and 8-O-4-diferulic acid linked to the O2-position of the nonreducing residue of two (1→5)-linked arabinobioses. To get insight into the structure and the degree of phenolic acid substitution of the diferuloylated polysaccharides, polymeric sugar composition, glycosidic linkages, and polysaccharide-bound monomeric phenolic acids and diferulic acids were analyzed. This study demonstrates that diferulic acids are involved into intramolecular and/or intermolecular cross-linking of arabinan chains and may have a major impact on cell wall architecture of quinoa and other dicotyledonous plants of the order of Caryophyllales.

Topics: Bolivia; Cell Wall; Chenopodium quinoa; Cinnamates; Coumaric Acids; Nuclear Magnetic Resonance, Biomolecular; Pectins; Polysaccharides; Seeds

Network structures created by hydroxycinnamate cross-links within the cell wall architecture of gramineous plants make the cell wall resistant to the gravitational force of the earth. In this study, the effects of microgravity on the formation of cell wall-bound hydroxycinnamates were examined using etiolated rice shoots simultaneously grown under artificial 1 g and microgravity conditions in the Cell Biology Experiment Facility on the International Space Station. Measurement of the mechanical properties of cell walls showed that shoot cell walls became stiff during the growth period and that microgravity suppressed this stiffening. Amounts of cell wall polysaccharides, cell wall-bound phenolic acids, and lignin in rice shoots increased as the shoot grew. Microgravity did not influence changes in the amounts of cell wall polysaccharides or phenolic acid monomers such as ferulic acid (FA) and p-coumaric acid, but it suppressed increases in diferulic acid (DFA) isomers and lignin. Activities of the enzymes phenylalanine ammonia-lyase (PAL) and cell wall-bound peroxidase (CW-PRX) in shoots also increased as the shoot grew. PAL activity in microgravity-grown shoots was almost comparable to that in artificial 1 g-grown shoots, while CW-PRX activity increased less in microgravity-grown shoots than in artificial 1 g-grown shoots. Furthermore, the increases in expression levels of some class III peroxidase genes were reduced under microgravity conditions. These results suggest that a microgravity environment modifies the expression levels of certain class III peroxidase genes in rice shoots, that the resultant reduction of CW-PRX activity may be involved in suppressing DFA formation and lignin polymerization, and that this suppression may cause a decrease in cross-linkages within the cell wall architecture. The reduction in intra-network structures may contribute to keeping the cell wall loose under microgravity conditions.

Topics: Cell Wall; Coumaric Acids; Lignin; Oryza; Peroxidase; Phenylalanine Ammonia-Lyase; Physiological Phenomena; Plant Shoots; Polysaccharides; Space Flight; Weightlessness

The consumption of wholemeal cereals has been associated with the reduced risk of several chronic diseases, and the mechanisms behind these protective effects may be linked, besides dietary fiber and micronutrients, to an increased intake of hydroxycinnamates contained in the bran. Among bran fractions, aleurone usually contains the highest concentration of ferulic acid and diferulic acid esters linked to arabinoxylans representing the most relevant subclasses. The aim of the present study was to evaluate the absorption of hydroxycinnamates by measuring the urinary metabolite profiles of rats fed with the two different aleurone fractions (the inner part of the aleurone, named wheat aleurone A, WA-A, and the outer part, named wheat aleurone B, WA-B). An acute feeding experiment with two rat groups consuming equivalent amounts of total ferulic acid from the different aleurone fractions was carried out to evaluate ferulic acid bioavailability as affected by different sources. A chronic feeding experiment was also conducted with two rat groups consuming the same amount of the two different aleurone fractions, carried out to investigate the short-term metabolism and absorption of aleurone phenolics. The results revealed higher increases in the 24 h-excretion of phenolic metabolites/catabolites in aleurone fed rats compared to rats fed with a regular diet. Specifically, in the chronic feeding, ferulic acid was more bioavailable when WA-A was ingested. Based on previous observations, demonstrating various positive physiological responses to ferulic acid and aleurone fractions characterized by higher phenolic bioavailability, our results indicate that the WA-A fraction has potentially interesting nutritional characteristics that might be used for the formulation of new wheat based products.

Topics: Animals; Biological Availability; Coumaric Acids; Dietary Fiber; Male; Micronutrients; Phenols; Rats; Rats, Wistar; Triticum

The relationship between the formation of cell wall-bound ferulic acid (FA) and diferulic acid (DFA) and the change in activities of phenylalanine ammonia-lyase (PAL) and cell wall-bound peroxidase (CW-PRX) was studied in rice shoots. The length and the fresh mass of shoots increased during the growth period from day 4 to 6, while coleoptiles ceased elongation growth on day 5. The amounts of FA and DFA isomers as well as cell wall polysaccharides continued to increase during the whole period. The activities of PAL and CW-PRX greatly increased in the same manner during the period. There were close correlations between the PAL activity and ferulate content or between the CW-PRX activity and DFA content. The expression levels of investigated genes for PAL and putative CW-PRX showed good accordance with the activities of these enzymes. These results suggest that increases in PAL and CW-PRX activities are cooperatively involved in the formation of ferulate network in cell walls of rice shoots and that investigated genes may be, at least in part, associated with the enzyme activities. The substantial increase in such network probably causes the maturation of cell walls and thus the cessation of elongation growth of coleoptiles.

Topics: Cell Wall; Cotyledon; Coumaric Acids; Gene Expression Regulation, Plant; Genes, Plant; Oryza; Peroxidase; Phenylalanine Ammonia-Lyase; Plant Growth Regulators; Plant Shoots

Oxalate oxidase (OXO) utilizes oxalate to generate hydrogen peroxide, and thereby acts as a source of hydrogen peroxide. The present study was carried out to investigate whether apoplastic OXO modifies the metabolism of cell wall-bound ferulates in wheat seedlings. Histochemical staining of OXO showed that cell walls were strongly stained, indicating the presence of OXO activity in shoot walls. When native cell walls prepared from shoots were incubated with oxalate or hydrogen peroxide, the levels of ester-linked diferulic acid (DFA) isomers were significantly increased. On the other hand, the level of ester-linked ferulic acid (FA) was substantially decreased. The decrease in FA level was accounted neither by the increases in DFA levels nor by the release of FA from cell walls during the incubation. After the extraction of ester-linked ferulates, considerable ultraviolet absorption remained in the hemicellulosic and cellulose fractions, which was increased by the treatment with oxalate or hydrogen peroxide. Therefore, a part of FA esters may form tight linkages within cell wall architecture. These results suggest that cell wall OXO is capable of modifying the metabolism of ester-linked ferulates in cell walls of wheat shoots by promoting the peroxidase action via supply of hydrogen peroxide.

Topics: Cell Wall; Coumaric Acids; Hydrogen Peroxide; Oxidoreductases; Peroxidase; Plant Proteins; Plant Shoots; Seedlings; Triticum

Since the presence of glyphosate in maize tissue cultures of proprietary line L2 was very detrimental to plant regeneration, we determined metabolic changes associated with the glyphosate effects on plant regeneration in maize cultures. The polar fraction composition and soluble and cell-wall-bound phenolics were analyzed in the regenerable (R) and non-regenerable (NR) calluses of maize line L2. The tissues with high regeneration capacity had low sugar and 4-aminobutyric acid (GABA) concentrations and increased concentrations of most amino acids, polyamines and indole-3-butenol in the soluble polar fraction and higher ferulic acid/coumaric acid and ferulic acid/diferulic acid ratios and higher levels of the predominant G (guaiacyl) units in the cell wall fraction compared with NR calluses as was found before with H99 and HiII maize R and NR tissues, indicating an association of these metabolites with the capacity of maize cultured tissue to regenerate plants. We also found that di-coumaroyl spermidine and coumaroyl-feruoyl spermidine are present in the soluble fraction of L2 R tissues and are practically absent in NR tissues. However, we did not see such differences in HiII and H99 samples, which indicate that these are genotypic features not related to the capacity to regenerate plants in maize tissue cultures. Glyphosate treatment caused the accumulation of shikimic and quinic acids (not detected in untreated samples) in R and NR calluses (with higher levels found in R tissues) and also decreased the FA/diFA ratio in cell wall phenolics, polyamine and amino acid levels, and increased sugar concentrations in the R L2 tissues, indicating a metabolic shift of R callus to NR tissues.

Topics: Carbohydrate Metabolism; Coumaric Acids; gamma-Aminobutyric Acid; Gene Expression Regulation, Plant; Glycine; Glyphosate; Quinic Acid; Regeneration; Shikimic Acid; Tissue Culture Techniques; Zea mays

Effects of silicon on the mechanical and chemical properties of cell walls in the second leaf of oat (Avena sativa L.) seedlings were investigated. The cell wall extensibility in the basal region of the second leaf was considerably higher than that in the middle and subapical regions. Externally applied silicon increased the cell wall extensibility in the basal region, but it did not affect the extensibility in the middle and subapical regions. The amounts of cell wall polysaccharides and phenolic compounds, such as diferulic acid (DFA) and ferulic acid (FA), per unit length were lower in the basal region than in the middle and subapical regions of the leaf, and silicon altered these amounts in the basal region. In this region, silicon decreased the amounts of matrix polymers and cellulose per unit length and of DFA and FA, both per unit length and unit matrix polymer content. Silicon treatment also lowered the activity of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) in the basal region. In contrast, the amount of silicon in cell walls increased in response to silicon treatment in three regions. These results suggest that in the basal region, silicon reduces the net wall mass and the formation of phenolic acid-mediated cross-linkages between wall polysaccharides. Such modifications of wall architecture may be responsible for the silicon-induced increase in the cell wall extensibility in oat leaves.

Topics: Ammonia-Lyases; Avena; Biomechanical Phenomena; Cell Wall; Coumaric Acids; Meristem; Phenylalanine Ammonia-Lyase; Plant Leaves; Silicon

The degradation of plant fiber by human gut microbiota could be restricted by xylan substitution and cross-linking by ferulate and diferulates, for example, by hindering the association of enzymes such as xylanases with their substrates. To test the influence of feruloylation on cell wall degradability by human intestinal microbiota, nonlignified primary cell walls from maize cell suspensions, containing various degrees of ferulate substitution and diferulate cross-linking, were incubated in nylon bags in vitro with human fecal microbiota. Degradation rates were determined gravimetrically, and the cell walls were analyzed for carbohydrates, ferulate monomers, dehydrodiferulates, dehydrotriferulates, and other minor phenolic constituents. Shifting cell wall concentrations of total ferulates from 1.5 to 15.8 mg/g and those of diferulates from 0.8 to 2.6 mg/g did not alter the release of carbohydrates or the overall degradation of cell walls. After 24 h of fermentation, the degradation of xylans and pectins exceeded 90%, whereas cellulose remained undegraded. The results indicate that low to moderate levels of ferulates and diferulates do not interfere with hydrolysis of nonlignified cell walls by human gut microbiota.

Topics: Bacteria; Cell Wall; Coumaric Acids; Cross-Linking Reagents; Fermentation; Humans; Intestines; Zea mays

Grass cell walls are atypical because their xylans are acylated with ferulate and lignins are acylated with p-coumarate. To probe the role and interactions of these p-hydroxycinnamates during lignification, feruloylated primary cell walls isolated from maize cell suspensions were lignified with coniferyl and sinapyl alcohols and with varying levels of p-coumarate esters. Ferulate xylan esters enhanced the formation of wall-bound syringyl lignin more than methyl p-coumarate, however, maximal concentrations of syringyl lignin were only one-third that of guaiacyl lignin. Including sinapyl p-coumarate, the presumed precursor of p-coumaroylated lignins, with monolignols unexpectedly accelerated peroxidase inactivation, interfered with ferulate copolymerization into lignin, and had minimal or adverse effects on cell wall lignification. Free phenolic groups of p-coumarate esters in isolated maize lignin and pith cell walls did not undergo oxidative coupling with each other or with added monolignols. Thus, the extensive formation of syringyl-rich lignins and the functional role of extensive lignin acylation by p-coumarate in grasses remains a mystery.

Topics: Cell Wall; Coumaric Acids; Hydrogen Peroxide; Lignin; Peroxidases; Xylans; Zea mays