tannins and proanthocyanidin

Topics: Anthocyanins; Flavonoids; Fruit; Humans; Lipid Bilayers; Lipids; Molecular Structure; Phenols; Polymers; Proanthocyanidins; Solubility; Tannins

Lentinus squarrosulus is a mushroom widely used in Gabon for its culinary and medicinal properties. The bioactive potential of mushrooms might be attributable to the presence of several pharmaceutically important mycocompounds that need to be ascertained scientifically. A study of the therapeutic potential of L. squarrosulus, the species of lignicolous fungus exploited in Gabon, was carried out on the basis of a chemical screening performed on three extracts in order to highlight different important chemical groups. This chemical screening was followed by a study of the fungus's antioxidant activity and prediction of its additional pharmacological activities. Chemical screening revealed that three extracts (aqueous, hydroethanolic, and ethanolic) of L. squarrosulus were almost free of tannins and were poor in total flavonoids and moderately rich in reducing sugars. Aqueous and ethanolic extracts were rich in total polyphenols, whereas aqueous and hydroethanolic extracts were rich in alkaloids. The aqueous extract was rich in saponosides and the hydroethanolic extract was rich in coumarins. The dosage of phenolic compounds confirmed the fungus's richness in total polyphenols, especially for aqueous and ethanolic extracts, its poverty in flavonoids and absence of tannins in ethanolic and hydroethanolic extracts. Regarding antioxidant activities, the results obtained for diphenyl picryl hydrazyl trapping tests showed that the different extracts tested had antioxidant activity ranging from low to moderate (0.12 ≤ antioxidant activity index [IAA] ≤ 0.6); the greatest activity was obtained with ethanolic extract (IAA = 0.6). Hence, we conclude that L. squarrosulus extracts can be used as easily accessible sources of natural antioxidants for potential preventative therapies.

Topics: Alkaloids; Antioxidants; Flavonoids; Gabon; Lentinula; Phenols; Polyphenols; Proanthocyanidins; Tannins

Topics: Antioxidants; Biflavonoids; Biological Availability; Catechin; Cicer; Correlation of Data; Flavonoids; Flavonols; Inhibitory Concentration 50; Iron Chelating Agents; Lens Plant; Mass Spectrometry; Metabolomics; Phenols; Polyphenols; Proanthocyanidins; Seeds; Tannins; Vicia faba

Cotton has the shortcomings of having no antibacterial, antioxidant and ultraviolet (UV) protection properties, which are of great importance for health protection purposes. In the present study, grape seed extract (GSE) mainly composed of proanthocyanins (tannins) was employed to simultaneously import pale colors and the three aforementioned functions to cotton fabric. The tests on the application conditions of GSE showed that pH and GSE concentration had great impact on the color depth of cotton fabric, and the color hue of dyed fabric could be controlled in the absence of pH regulators due to the weakly acidic nature of GSE solution. The fabric dyed with 10%owf (on the weight of fabric) GSE exhibited an excellent inhibition effect towards

Topics: Anti-Bacterial Agents; Antioxidants; Coloring Agents; Cotton Fiber; Escherichia coli; Gossypium; Grape Seed Extract; Hydrogen-Ion Concentration; Microbial Sensitivity Tests; Proanthocyanidins; Tannins; Textiles; Ultraviolet Rays

Identifying the maximum level of inherent defense against harmful insects in natural variation among wild lineages of crop plants may result in high yield tolerant varieties and reducing use of chemical insecticides. However, knowledge of natural cotton genotypes with high insect-resistance is still indistinguishable at the biochemical or molecular level. In the present study, different cultivated

Topics: Animals; Genotype; Gossypium; Hydroxybenzoates; Moths; Plants, Genetically Modified; Proanthocyanidins; Tannins

This study, the first to assess the total phenolic, flavonoid, tannins, and proanthocyanidin content of the Tunisian lichen Diploschistes ocellatus, determined the antioxidant capacity in scavenging 2,2 diphenyl-1-picrylhydrazyl (DPPH), as well as the ferric-reducing and iron-chelating powers. The phenolic compound content of D. ocellatus was shown to be related to antioxidant activity. The highest phenolic and flavonoid contents of extracts were obtained with acetone (286.3 μg GAE/g DW and 3.24 μg CE/g DW, respectively), while the highest tannin and proanthocyanidin contents were obtained with methanol (5.5 μg TAE/g DW and 35.12 μg CE/g DW, respectively). The highest DPPH' scavenging capacity and iron-chelating power of extracts were obtained with methanol (concentration providing 50% inhibition [IC50] = 0.029 mg/mL and IC50 = 0.425 mg/mL, respectively), while acetone extracts showed a higher reducing power (IC50 = 0.118 mg/mL).

Topics: Antioxidants; Ascomycota; Biphenyl Compounds; Chelating Agents; Flavonoids; Free Radical Scavengers; Lichens; Phenols; Picrates; Proanthocyanidins; Secondary Metabolism; Tannins

The present study aimed to investigate the reciprocal effects of Phoradendron perrottetii (mistletoe) and T. guianensis (host plant) regarding their polyphenol composition. Taking into account that tannins are important molecules in plant defense and their biosynthesis tends to be enhanced when a species is exposed to stress, we address the following questions: (1) Are the tannins found in our model species important in the interaction between host and mistletoe? (2) Does the presence of mistletoe induce changes in the content of tannins and other polyphenols in the host plant? (3) Do we find differences between the tannin sub-groups in the responses of the host plant to mistletoe? (4) Could the observed differences reflect the relative importance of one tannin group over another as chemical defense against the mistletoe? Using a polyphenol and tannin group-specific MRM methods we quantified four different tannin sub-groups together with flavonoid and quinic acid derivatives by ultra-performance liquid chromatography tandem mass spectrometry together with the oxidative and protein precipitation activities of leaves and branches of Tapirira guianensis and Phoradendron perrottetii. We selected leaves and branches of six non-parasitized trees of T. guianensis. Leaves and branches of nine individuals of T. guianensis parasitized by P. perrottetii were also sampled. For each parasitized tree, we sampled an infested branch and its leaves, as well as a non-infested branch and its leaves. Infested branches were divided into three groups: gall (the host-parasite interface), proximal, and distal region. Both proanthocyanidins and ellagitanins seem to be important for plant-plant parasitism interaction: host infested tissues (gall and surrounding regions) have clearly less tannin contents than healthy tissues. Mistletoe showed high levels of quinic acid derivatives and flavonoids that could be important during hastorium formation and intrusion on host tissues, suggesting a defense mechanism that could promote oxidative stress together with an inhibition of mistletoe seed germination, consequently avoiding secondary infestations. Polyphenol detected in T. guianensis-P. perrottetii interaction could play different role as plant-mistletoe strategies of survival.

Topics: Anacardiaceae; Flavonoids; Host-Parasite Interactions; Hydrolyzable Tannins; Phoradendron; Polyphenols; Proanthocyanidins; Quinic Acid; Reactive Oxygen Species; Tannins

The interactions between pectins of different degrees of esterification (DE) and highly galloylated persimmon tannins with average degrees of polymerisation (DP26 and DP5) were investigated by UV-Vis spectrophotometry, dynamic light scattering, transmission electron microscopy, isothermal titration calorimetry and pyrene fluorescence methods Pectins displayed strong effects on the self-aggregation of persimmon tannins and improved the homogeneity of condensed tannin aggregates. The interaction between tannins and pectins may result from hydrogen bonding and hydrophobic interactions; by contrast, electrostatic interactions, which involve charged molecules in general, played no dominant role. In addition, the presence of gallate moieties in the high-polymerisation proanthocyanidin could enhance affinity with highly methylated pectins. Stronger association was observed with the high-polymerisation tannins (DP26) with high-methoxyl pectin (DE74) (Ka=(8.50±3.0)×10

Topics: Diospyros; Esters; Fluorescent Dyes; Fruit; Gallic Acid; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Kinetics; Methylation; Pectins; Proanthocyanidins; Pyrenes; Spectrometry, Fluorescence; Tannins; Thermodynamics

For the first time vine-shoot tannin composition was carried out by means of HPLC-DAD-ESI-MS/MS. Two vine-shoot cultivars (Airén and Cencibel) with different post-pruning storage times were submitted to a toasting process and assayed. There were no traces of gallotannins nor ellagitannins, but a high proanthocyanidin content and a mean degree of polymerization (mDP) close to 3 were characterized. The higher concentration of proanthocyanidins corresponded to Airén after 6 months post-pruning storage and at 3 months for Cencibel. Procyanidins were the most abundant fraction (70-95%), which decreased with storage, and especially significant was the contribution of B1, B2, and B4 dimers. Prodelphinidins were also found (8-24%), increasing their % with storage time. Toasting produced a considerable reduction of proanthocyanidin content and a loss of a monomer mDP unit, suggesting that if used as oenological tannins, then they may be more bitter and less astringent when compared with the nontoasted vine-shoot samples.

Topics: Chromatography, High Pressure Liquid; Hot Temperature; Plant Extracts; Plant Shoots; Plant Stems; Polymerization; Proanthocyanidins; Tandem Mass Spectrometry; Tannins; Vitis

Isothermal titration calorimetry was applied to study the binding of purified proanthocyanidin oligomers to bovine serum albumin (BSA). The molecular weight of the proanthocyanidin oligomer had a major impact on its binding to BSA. The calculated change in enthalpy (ΔH) and association constant (Ka) became greater as the oligomer size increased then plateaued at the heptameric oligomer. These results support a model for precipitation of proteins by proanthocyanidin where increased oligomer size enhanced the opportunity for cross linkages between proteins ultimately forming sediment-able complexes. The authors suggest tannin binding to proteins is opportunistic and involves multiple sites, each with a different Ka and ΔH of binding. The ΔH of binding comprises both an endothermic hydrophobic interaction and exothermic hydrogen bond component. This suggests the calculated entropy value (ΔS) for tannin-protein interactions is subject to a systematic error and should be interpreted with caution.

Topics: Animals; Calorimetry; Cattle; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Proanthocyanidins; Serum Albumin, Bovine; Tannins; Thermodynamics

In this work, the effect of water availability on astringency of seed and skin extracts of Vitis vinifera cv. Syrah berries under the typical semiarid conditions of Greece was investigated. Moreover, astringency was assessed in relation to proanthocyanidin composition. For this purpose, three irrigation treatments were applied starting at berry set through harvest of 2011 and 2012: full irrigation (FI) at 100% of crop evapotranspiration, deficit irrigation (DI) at 50% and non-irrigated (NI). FI skin and seed extracts were perceived significantly more astringent than NI. Total phenol, total tannin, (+)-catechin, (-)-epicatechin and procyanidin C1 concentrations were positively correlated with astringency. Positive correlations were also obtained among astringency and average degree of polymerization and proportion of the extension units of shorter tannins while astringency of larger tannins was correlated with the proportion of terminal units. On the contrary, total anthocyanin and epigallocatechin contents were negatively correlated with astringency.

Topics: Agricultural Irrigation; Anthocyanins; Biflavonoids; Catechin; Desert Climate; Fruit; Greece; Humans; Phenols; Plant Extracts; Proanthocyanidins; Seeds; Tannins; Taste; Vitis; Water

The brown color of Arabidopsis seeds is caused by the deposition of proanthocyanidins (PAs or condensed tannins) in their inner testa layer. A transcription factor complex consisting of TT2, TT8 and TTG1 controls expression of PA biosynthetic genes, just as similar TTG1-dependent complexes have been shown to control flavonoid pigment pathway gene expression in general. However, PA synthesis is controlled by at least one other gene. TTG2 mutants lack the pigmentation found in wild-type seeds, but produce other flavonoid compounds, such as anthocyanins in the shoot, suggesting that TTG2 regulates genes in the PA biosynthetic branch of the flavonoid pathway. We analyzed the expression of PA biosynthetic genes within the developing seeds of ttg2-1 and wild-type plants for potential TTG2 regulatory targets. We found that expression of TT12, encoding a MATE type transporter, is dependent on TTG2 and that TTG2 can bind to the upstream regulatory region of TT12 suggesting that TTG2 directly regulates TT12. Ectopic expression of TT12 in ttg2-1 plants partially restores seed coat pigmentation. Moreover, we show that TTG2 regulation of TT12 is dependent on TTG1 and that TTG1 and TTG2 physically interact. The observation that TTG1 interacts with TTG2, a WRKY type transcription factor, proposes the existence of a novel TTG1-containing complex, and an addendum to the existing paradigm of flavonoid pathway regulation.

Topics: Arabidopsis; Arabidopsis Proteins; Biological Transport; Color; Flavonoids; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; Proanthocyanidins; Protein Interaction Mapping; Seeds; Tannins; Transcription Factors; Vacuoles

Commercial enological tannins were used to investigate the role that cell wall material plays in proanthocyanidin adsorption. Insoluble cell wall material, prepared from the skin of Vitis vinifera L. cv. Monastrell berries, was combined with solutions containing six different commercial enological tannins (proanthocyanidin-type tannins). Analysis of the proanthocyanidins in the solution, after fining with cell wall material, using phloroglucinolysis and size exclusion chromatography, provided quantitative and qualitative information on the non-adsorbed compounds. Cell wall material showed strong affinity for the proanthocyanidins, one of the commercial tannins being bound up to 61% in the experiment. Comparison of the molecular mass distribution of the commercial enological tannins in solution, before and after fining, suggested that cell walls affinity for proanthocyanidins was more related with the proanthocyanidin molecular mass than with their percentage of galloylation. These interactions may have some enological implications, especially as regards the time of commercial tannins addition to the must/wine.

Topics: Adsorption; Cell Wall; Fruit; Molecular Weight; Plant Extracts; Proanthocyanidins; Seeds; Tannins; Vitis

(13)C NMR is an effective method of characterizing proanthocyanidin (PAC) tannins in quebracho (Schinopsis lorentzii) heartwood and black wattle (Acacia mearnsii) bark, before and after commercial extraction. The B-rings of the constituent flavan-3-ols, catechols (quebracho) or pyrogallols (wattle), are recognized in unprocessed source materials by "marker" signals at ca. 118 or 105ppm, respectively. NMR allows the minimum extraction efficiency to be calculated; ca. 30%, and ca. 80%, for quebracho heartwood and black wattle bark, respectively. NMR can also identify PAC tannin (predominantly robinetinidin), and compare tannin content, in bark from other acacia species; tannin content decreases in the order A. mearnsii, Acacia pycnantha (87% of A. mearnsii), Acacia dealbata and Acacia decurrens (each 74%) and Acacia karroo (30%). Heartwood from an underexploited PAC tannin source, Searsia lancea, taxonomically close to quebracho, shows abundant profisetinidin and catechin PACs. NMR offers the advantage of being applicable to source materials in their native state, and has potential applications in optimizing extraction processes, identification of tannin sources, and characterization of tannin content in cultivar yield improvement programmes.

Topics: Acacia; Anacardiaceae; Catechols; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Structure; Plant Bark; Plant Extracts; Proanthocyanidins; Pyrogallol; Rhus; Tannins; Wood

We have established a simple method for preparing large quantities of A-type dimers from peanut skin and persimmon for further structure-activity relationship study. Peanut skins were defatted with hexane and oligomeric proanthocyanidins were extracted from it with 20% of methanol, and the extract was fractionated with ethyl acetate. Persimmon tannin was extracted from persimmon with methanol acidified with 1% hydrochloric acid, after removing the sugar and small phenols, the high molecular weight persimmon tannin was partially cleaved with 6.25% hydrochloric acid in methanol. The ethyl acetate fraction from peanut skins and persimmon tannin cleaved products was chromatographed on AB-8 macroporous resin followed by Toyopearl HW-50F resin to yield about 378.3mg of A-type (epi)catechin (EC) dimer from 1 kg dry peanut skins and 34.3mg of A-type (epi)catechin-3-O-gallate (ECG) dimer and 37.7 mg of A-type (epi)gallocatechin-3-O-gallate (EGCG) dimer from 1 kg fresh persimmon fruit. The antioxidant properties of the A-type and B-type dimers were compared in five different assays, namely, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical, hydroxyl radical, lipid peroxidation in mice liver homogenate and erythrocyte hemolysis in rat blood. Our results showed that both A-type and B-type dimers showed high antioxidant potency in a dose-dependent manner. In general, B-type dimers showed higher radical scavenging potency than A-type ones with the same subunits in aqueous systems. But in tissue or lipid systems, A-type dimers showed similar or even higher antioxidant potency than B-type ones.

Topics: Animals; Antioxidants; Arachis; Catechin; Dimerization; Diospyros; Dose-Response Relationship, Drug; Erythrocytes; Fruit; Hydroxyl Radical; Lipid Peroxidation; Liver; Mice; Plant Extracts; Proanthocyanidins; Rats; Seeds; Structure-Activity Relationship; Tannins

A detailed assessment of the total phenolic and total tannin contents, the monomeric and oligomeric flavan-3-ol composition, the proanthocyanidin profile, and the antioxidant potential of the grape pomace byproducts (considered as a whole, both skins and seeds), derived from four white grape varieties (Vitis vinifera L.), was performed. Significant differences (p < 0.05) of the total phenolic content, total tannin content, and antioxidant capacity of grape pomace byproducts were observed among the different grape varieties studied. For the first time in the literature, the particular flavan-3-ol composition of the four grape varieties investigated was described for the whole fraction of their grape pomace byproducts. The phenolic composition and antioxidant capacity of grape pomaces were compared to those of their corresponding stems. The global characterization of these white grape varieties provided a basis for an integrated exploitation of both winemaking byproducts as potential, inexpensive, and easily available sources of bioactive compounds for the pharmaceutical, cosmetic, and food industries.

Topics: Antioxidants; Chromatography, High Pressure Liquid; Flavonoids; Food Handling; Polyphenols; Proanthocyanidins; Tannins; Vitis; Wine

Antioxidant characteristics of leaves, twigs, and acorns from two Serbian oak species Quercus robur L. and Quercus petraea L. from Vojvodina province (northern Serbia) were investigated. 80% ethanol (in water) extracts were used for antiradical power (ARP) determinations against DPPH(•), (•)NO, and O2 (•-) radicals, ferric reducing antioxidant power (FRAP), total phenol, tannin, flavonoid, and proanthocyanidin contents. Permanganate reducing antioxidant capacity (PRAC) was determined using water extracts. Beside, mentioned parameters, soluble proteins, lipid peroxidation (LP), pigments and proline contents were also determined. The data of different procedures were compared and analyzed by multivariate techniques (correlation matrix calculation and principal component analysis (PCA)). PCA found that investigated organs of two different oak tree species possess similar antioxidant characteristics. The superior antioxidant characteristics showed oak leaves over twigs and acorns and seem to be promising source of antioxidants with possible use in industry and pharmacy.

Topics: Antioxidants; Chemistry Techniques, Analytical; Ethanol; Flavonoids; Free Radicals; Hydroxyl Radical; Lipid Peroxidation; Multivariate Analysis; Phenol; Pigmentation; Plant Extracts; Principal Component Analysis; Proanthocyanidins; Proline; Quercus; Spectrophotometry; Tannins; Trees

This study, for the first time, investigated the in vitro inhibitory effects of Potentilla recta extracts and subfractions obtained with solvents of different polarity (aqueous, 50% ethanol, diethyl ether, ethyl acetate and n-butanol) against cariogenic Streptococcus spp. strains. It was found that the tested samples inhibited the growth of oral streptococci. Furthermore, all five P. recta preparations exhibited an inhibitory effect on water-insoluble α-(1→3)-,α-(1→6)-linked glucan (mutan) and artificial dental plaque formation. The ethyl acetate fraction showed the highest antibiofilm activities especially against S. sobrinus GCM 20381, with minimum mutan and biofilm inhibition concentrations of 6.25 and 25 µg/mL, respectively. The phytochemical profile of active constituents in the investigated samples was analysed. The high polyphenolics (total phenol, phenolic acids, tannins, proantocyanidins, flavonoids) content were found. The ethyl acetate fraction showed the highest concentration of total polyphenol content which may correlate with the high cariogenic activity of this subfraction. The results demonstrate that P. recta extracts and subfractions could become useful supplements for pharmaceutical products as new anticariogenic agents in a wide range of oral care products. Further studies are necessary to clarify the precise bioactive constituents of P. recta responsible for the anticariogenic properties.

Topics: Anti-Bacterial Agents; Biofilms; Cariostatic Agents; Dental Plaque; Flavonoids; Microbial Sensitivity Tests; Phenols; Plant Components, Aerial; Plant Extracts; Polyphenols; Potentilla; Proanthocyanidins; Streptococcus sobrinus; Tannins

The literature on proanthocyanidins (tannins) in ecological systems is dominated by quantitative studies. Despite evidence that the qualitative characteristics (subunit type, polymer chain length) of these complex polyphenolics are important determinants of biological activity, little is known about genetic and environmental controls on the type of proanthocyanidins produced by plants. We tested the hypothesis that genetics, season, developmental stage, and environment determine proanthocyanidin qualitative characteristics by using four Populus "cross types" (narrowleaf [P. angustifolia], Fremont [P. fremontii], F1 hybrids, and backcrosses to narrowleaf). We used thiolysis and HPLC analysis to characterize the proanthocyanidins, and found that genetics strongly control composition. The narrowleaf plants accumulate mixed procyanidin/prodelphinidins with average composition epicatechin(11)-epigallocatechin(8)-catechin(2)-catechin((terminal)). Backcross genotypes produce mixed procyanidin/prodelphinidins similar to narrowleaf, while Fremont makes procyanidin dimers, and the F1 plants contain procyanidin heptamers. Less striking effects were noted for genotype × environment, while season and developmental zone had little effect on proanthocyanidin composition or chain length. We discuss the metabolic and ecological consequences of differences in condensed tannin qualitative traits.

Topics: Chromatography, High Pressure Liquid; Electrochemistry; Genes, Plant; Hybridization, Genetic; Mass Spectrometry; Plant Leaves; Populus; Proanthocyanidins; Spectrophotometry, Ultraviolet; Tannins

MALDI-TOF MS suggested that the high molecular weight proanthocyanidin (condensed tannin) from persimmon (Diospyros kaki L.) pulp comprised a heteropolyflavanol series with flavan-3-O-galloylated extenders, flavan-3-ol and flavonol terminal units, and A-type interflavan linkages. Thiolysis-HPLC-ESI-MS with DAD, electrochemical, and ESI-MS detection confirmed a previously unreported terminal unit, the flavonol myricetin, in addition to the typical flavan-3-ols catechin and epigallocatechin gallate. The extender units were epicatechin, epigallocatechin, (epi)gallocatechin-3-O-gallate, and (epi)catechin-3-O-gallate. The crude tannin had a high prodelphinidin content (65%) and a high degree of 3-O-galloylation (72%). The material was fractionated on Toyopearl TSK-HW-50-F to yield fractions distinguished by degree of polymerization (DP). Thiolysis suggested that the persimmon tannin was composed of polymers ranging from 7 to 20 kDa (DP 19-47), but sizes estimated by GPC were 50-70% smaller. The crude material was chemically degraded with acid to yield products that were amenable to NMR and ESI-MS analysis, which were used to establish for the first time that persimmon tannin has a mixture of B-type and A-type linkages.

Topics: Chromatography, Gel; Chromatography, High Pressure Liquid; Diospyros; Flavonoids; Flavonols; Molecular Weight; Proanthocyanidins; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Tannins

Grape variety [Cabernet Sauvignon (CS) and Merlot (M)] effect on the proanthocyanidin composition and sensory perception of wine grapes from Bordeaux vineyards for two successive vintages (2006 and 2007) is reported. The flavan-3-ol monomers [(+)-catechin = C, (-)-epicatechin = EC, (-)-epicatechin-O-gallatte = ECG] and the proanthocyanidin oligomers [dimers B1, B2, B3, and B4 and trimer Cat-Cat-Epi (T)] in grape seed and skin tannin extracts were identified and quantified at harvest. Proanthocyanidin subunit compositions, percentage of galloylation (%G), and percentage of prodelphinidins (%P) as well as mean degree of polymerization (mDP) of the proanthocyanidin fraction were determined. Sensory analysis concerning the astringency and bitterness intensity of the proanthocyanidins of skin and seed tannin extracts was also performed. The results showed that proanthocyanidin composition can be greatly affected by grape variety. For both vintages between CS and M, significant differences were found on mDP (p < 0.05) in seed tannin extracts, whereas in skin tannin extracts, significant differences were observed for %G and %P (p < 0.05). Sensory analysis showed that grape variety influenced neither astringency nor bitterness intensity perception for both skin and seed tannin extracts for the two successive vintages studied. A positive correlation was found between astringency intensity, mDP, and B3 content in skin tannin extracts.

Topics: Female; Fermentation; Humans; Male; Plant Extracts; Proanthocyanidins; Seeds; Tannins; Taste Perception; Vitis; Wine

The antioxidant potential of ethanol extracts from defatted Bokbunja seed wastes generated during wine processing were estimated by radical scavenging abilities (DPPH(*), H(2)O(2), and O(2)(*-)), retardation of lipid oxidation, and iron ion-chelating characteristics. For comparison, ethanol extracts from seeds of fresh ripe Bokbunja fruits were also used. The ethanol extracts from the wine seed waste always showed higher scavenging activities against DPPH(*), H(2)O(2), and O(2)(*-) than those from the fresh seeds. The oxidation of linoleic acid in dimethylsulfoxide at 105 degrees C revealed that the kinetic behavior clearly obeyed pseudo-zero-order regardless of the linoleic acid concentration. The Fe(II)-chelating capacity was determined by the Freundlich isotherm. The results showed high potential and favorability of the two extracts for Fe(II) chelation. The Freundlich chelation capacities (mg(1-1/n)L(1/n)/g) of both ethanol extracts from seeds of fresh Bokbunja and wine processing wastes, tannic acid, and proanthocyanidin from Pinus radiata bark were 100, 224, 260, and 307, respectively. The Fe(III)-chelating properties of the ethanol extracts were considered to be deeply associated with its 3',4',5'-trihydroxyl (galloyl) group as with tannic acid.

Topics: Antioxidants; Biotechnology; Biphenyl Compounds; Chelating Agents; Ethanol; Free Radical Scavengers; Hydrazines; Hydrogen Peroxide; Iron; Linoleic Acid; Lipids; Oxygen; Picrates; Proanthocyanidins; Seeds; Tannins; Wine

Quantitative and qualitative modifications of tannins and anthocyanins in grape skin were investigated at different dates of harvest, from berries sorted on the basis of their density. Free anthocyanins accumulated until 170 g/L of sugars in pulp before undergoing a slight decrease. Changes in anthocyanin composition were observed with increasing sugar levels in the pulp that reflected structural differences between classes of anthocyanins. The proportion of methoxylated anthocyanins continued to increase in the skin as sugar accumulated while the proportion of coumaroylated anthocyanins initially increased (up to 200 g/L of sugars in the pulp) and then rapidly decreased. In comparison, no major quantitative nor qualitative change was observed for tannins, except for a slight increase of the mean degree of polymerization. Whatever the physiological stage of the pulp, the extraction yield of skin phenolics into hydroalcoholic solution for 5 h was lower than 77% for anthocyanins and 38% for proanthocyanidins. For both classes of compounds, no clear evolution in these extraction yields could be observed as sugars accumulated in pulp (from 162.6 to 275.0 g/L). Nevertheless, some structural features within each family of compounds significantly influenced extractability, for example, a lower extraction yield for coumaroylated anthocyanins and for tannins with a high degree of polymerization. Finally, no direct relationship could be found in extraction media between the amounts of all red pigments (measured in acidic conditions) and the color intensity at 520 nm (measured in wine-like model solutions).

Topics: Anthocyanins; Carbohydrates; Chromatography, High Pressure Liquid; Fruit; Kinetics; Proanthocyanidins; Tannins; Vitis

Topics: Anthocyanins; Arabidopsis; Arabidopsis Proteins; Cloning, Molecular; Genes, Plant; Medicago; Molecular Conformation; NADH, NADPH Oxidoreductases; Nicotiana; Oxidation-Reduction; Oxygenases; Proanthocyanidins; Recombinant Proteins; Stereoisomerism; Tannins

Condensed tannins (CTs) are flavonoid oligomers, many of which have beneficial effects on animal and human health. The flavanol (-)-epicatechin is a component of many CTs and contributes to flavor and astringency in tea and wine. We show that the BANYULS (BAN) genes from Arabidopsis thaliana and Medicago truncatula encode anthocyanidin reductase, which converts anthocyanidins to their corresponding 2,3-cis-flavan-3-ols. Ectopic expression of BAN in tobacco flower petals and Arabidopsis leaves results in loss of anthocyanins and accumulation of CTs.

Topics: Amino Acid Sequence; Anthocyanins; Arabidopsis; Arabidopsis Proteins; Catechin; Circular Dichroism; Genes, Plant; Magnetic Resonance Spectroscopy; Medicago; Molecular Sequence Data; NAD; NADH, NADPH Oxidoreductases; NADP; Nicotiana; Oxidation-Reduction; Oxygenases; Plants, Genetically Modified; Proanthocyanidins; Recombinant Proteins; Seeds; Stereoisomerism; Tannins

Samples of the tropical forage legumes Vigna unguiculata (L.) Walp (cowpea), Desmodium uncinatum (silverleaf desmodium), Stylosanthes guianensis (oxley fine stem stylo) and Stylosanthes scabra (fitzroy) and of natural pasture (veld) hay were analysed and ranked according to their proanthocyanidin (PA) and saponin content. Silverleaf desmodium and fitzroy leaf and stem samples of different ages were also separately analysed for the PA contents. All the samples analysed contained some PA but no saponins. High levels of PA were detected in silverleaf desmodium and very low levels in veld hay and cowpea. In all samples, more of the tannins were bound to protein or neutral detergent fibre (NDF) than were extractable, most being bound to proteins. The proportion of the unextractable PA was greater in younger than in mature materials.

Topics: Animal Feed; Anthocyanins; Antioxidants; Dietary Fiber; Dietary Proteins; Fabaceae; Linear Models; Plant Extracts; Plants, Medicinal; Poaceae; Proanthocyanidins; Saponins; Tannins; Zimbabwe

Proanthocyanidins (condensed tannins) frequently need to be quantified in large numbers of samples in food, plant, and environmental studies. An automated colorimetric method to quantify proanthocyanidins with sulfuric acid (H(2)SO(4)) was therefore developed for use in a continuous flow analyzer. Assay conditions were optimized using 50% methanol extracts of paper birch, sugar maple, and quaking aspen leaves. Short extraction times and centrifugation of samples prevented proanthocyanidin degradation that otherwise occurred in 50% methanol extracts of aspen leaves. Extraction of birch and maple proanthocyanidins with 50% methanol was comparable to or better than that with 70% acetone. Proanthocyanidin levels in aspen were lower when extracted with aqueous methanol, but relative differences among samples were consistent with those found in aqueous acetone extracts. Results from the automated sulfuric acid assay were highly correlated with those of the conventional BuOH-HCl method for proanthocyanidins and, except for birch, with the Folin--Denis assay for total phenolics. This new technique significantly improves assay processing rate and repeatability compared to conventional colorimetric proanthocyanidin assays.

Topics: Anthocyanins; Antioxidants; Colorimetry; Plant Extracts; Proanthocyanidins; Sulfuric Acids; Tannins; Trees

We investigated a number of natural polyphenols representing flavan-3-ols, gallotannins, and ellagitannins with regard to their antioxidant potential. For this purpose we used pulse radiolysis to determine scavenging rate constants with hydroxyl radicals and decay rates of the respective aroxyl radicals and EPR spectroscopy to identify the radicals after in situ oxidation. Using NMR spectroscopy, we could confirm phenolic coupling reactions of epigallocatechin gallate and pentagalloyl glucose after radical-induced oxidation.

Topics: Anthocyanins; Antioxidants; Catechin; Dimerization; Electron Spin Resonance Spectroscopy; Hydrogen Peroxide; Hydrolysis; Hydrolyzable Tannins; Hydroxyl Radical; Magnetic Resonance Spectroscopy; Models, Chemical; Oxygen; Phenol; Proanthocyanidins; Tannins; Time Factors

The contents of soluble, SDS-extractable, and insoluble condensed tannins were determined in canola/rapeseed hulls from several varieties by utilizing the proanthocyanidin assay. The total amount of tannins in rapeseed/canola hulls ranged from 1913 to 6213 mg per 100 g of oil-free hulls. Insoluble tannins predominated in canola/rapeseed hulls and comprised from 70 to 95.8% of total tannins present. The amounts of SDS-extractable tannins were comparable to those of soluble tannins but constituted only 4.7-14. 1% of insoluble tannins present.

Topics: Anthocyanins; Brassica; Proanthocyanidins; Solubility; Tannins

The active components of an aqueous extract of Sanguisorbae Radix, which possesses nitric oxide (NO) production-suppressing activity, were determined using macrophages that were activated by the addition of lipopolysaccharide. Significant inhibitory activity against the formation of both NO and inducible NO synthase, and NADPH-diaphorase activity, which is involved in NO generation, was shown by Sanguisorbae Radix fractions T-B and T-C. On further fractionation, the subfractions of T-B and T-C all showed high anti-NO activity. Sanguiin H-6, sanguiin H-11, 1,2,3,4,6-penta-O-galloyl-beta-D-glucose, eugeniin and polymeric proanthocyanidin were isolated from TB-3 and TC-4, and all were identified as exhibiting strong anti-NO activity. We have confirmed that sanguiin H-6 is the most active component of Sanguisorbae Radix with respect to the suppression of NO production. It is suggested that tannin makes a prominent contribution to the biological activity of Sanguisorbae Radix.

Topics: Animals; Anthocyanins; Cells, Cultured; Drugs, Chinese Herbal; Gallic Acid; Glucosides; Hydrolyzable Tannins; Magnetic Resonance Spectroscopy; Male; Mice; Mice, Inbred BALB C; NADPH Dehydrogenase; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Proanthocyanidins; Spectrometry, Mass, Fast Atom Bombardment; Tannins

We described the effects of two East African browses, Acacia brevispica and Sesbania sesban, on nitrogen metabolism of sheep and goats. The A. brevispica had a substantial amount of proanthocyanidins (condensed tannins); S. sesban did not. The browses were fed at three levels in combination with vetch (Vicia dasycarpa) and teff straw (Eragrostis abyssinica). Fecal N, N balance, and plasma urea N (PUN) were estimated with intact animals. Ruminal ammonia (RuA) and VFA concentrations were estimated with ruminally fistulated animals. Urinary N loss, PUN, RuA, and VFA concentrations were higher for S. sesban diets than for A. brevispica diets. Fecal N was highest with diets including A. brevispica due to high levels of fecal neutral-detergent insoluble N. Nitrogen retention was highest for diets including S. sesban. Nitrogen retention was adequate for A. brevispica diets because low urinary N compensated for high fecal N. Four hypotheses describe possible effects of tannins on N metabolism: 1) escape of protein from the rumen to the lower tract; 2) increased microbial yield; 3) increase in N-containing endogenous products; and 4) protein made indigestible in tannin-protein complexes. The effect of tannins in A. brevispica on N metabolism can best be described by the formation of indigestible tannin-protein complexes, although increased production of endogenous products is also possible.

Topics: Acacia; Ammonia; Analysis of Variance; Animal Nutritional Physiological Phenomena; Animals; Anthocyanins; Antioxidants; Blood Urea Nitrogen; Digestion; Eating; Ethiopia; Fatty Acids, Volatile; Feces; Goats; Male; Nitrogen; Proanthocyanidins; Rumen; Sheep; Tannins; Trees

The hydrophobicity values of hydrolyzable tannins were evaluated by measuring the distribution of the compounds between n-octanol and water. Of 8 gallotannins and 13 ellagitannins examined, pentagalloylglucose (7), the major polyphenol of Paeoniae Radix, showed the largest partition coefficient value. In aqueous solution, pentagalloylglucose associated with various crude drug constituents, such as paeoniflorin, glycyrrhizin potassium salt, aconitine trifluoroacetate, liquiritin apioside and amygdalin. The 1H-NMR spectroscopic examination suggested that the association occurred preferentially at the most hydrophobic sites of the molecules. The association with these compounds inhibited the distribution of pentagalloylglucose into the n-octanol phase and adsorption on hide powder. In addition, the water solubility of the biologically active polymeric proanthocyanidins of rhubarb was increased by association with rhein 8-O-glucoside potassium salt, the major anthraquinone glycoside of rhubarb.

Topics: 1-Octanol; Aconitine; Amygdalin; Anthocyanins; Anti-Inflammatory Agents, Non-Steroidal; Benzoates; Biphenyl Compounds; Bridged-Ring Compounds; Ellagic Acid; Glucosides; Glycyrrhizic Acid; Hydrolysis; Magnetic Resonance Spectroscopy; Monoterpenes; Plant Extracts; Plants, Medicinal; Proanthocyanidins; Rheum; Solutions; Tannins; Water

Leaves of sericea lespedeza exhibit a high proportion of condensed tannin, resulting in poor forage quality. The white rot fungi Ceriporiopsis subvermispora and Cyathus sterocoreus are known to preferentially degrade lignin in a variety of plants and were evaluated for their ability to degrade condensed tannin from sericea leaves with the aim of improving digestibility. Relative levels of condensed tannin, cutin, pectin, and cellulose were monitored as a function of fungal treatment by solid-state cross-polarization and magic angle spinning 13C nuclear magnetic resonance spectroscopy. Total soluble phenolics, soluble tannins, and soluble and insoluble proanthocyanidin levels in fungus-treated and control samples were measured by established chemical techniques. Results indicate that both species of fungus preferentially degrade condensed tannin and that C. subvermispora is markedly superior to C. stercoreus in this capacity.

Topics: Anthocyanins; Basidiomycota; Biodegradation, Environmental; Cellulose; Fabaceae; Magnetic Resonance Spectroscopy; Membrane Lipids; Pectins; Phenols; Plant Proteins; Plants, Medicinal; Polyporales; Proanthocyanidins; Tannins

A valuable method for specific localization of proanthocyanidins in plant tissues is given. The specificity is based on the acid hydrolysis of condensed tannins in situ via hot sulfuric acid, yielding bright red anthocyanidins. This treatment did not cause noticeable damage of tissue embedded in glycol methacrylate prior to sectioning. Further proof of specificity was achieved by control staining with the flavan-3-ol-selective p-dimethylaminocinnamaldehyde (DMACA) reagent. In addition, comparison of adjacent sections stained with the DMACA reagent may give coarse information about the degree of polymerization of the proanthocyanidins.

Topics: Anthocyanins; Histocytochemistry; Hydrolysis; Plant Cells; Plants; Proanthocyanidins; Staining and Labeling; Sulfuric Acids; Tannins; Tissue Embedding

Topics: Anthocyanins; Fabaceae; Plants, Medicinal; Plants, Toxic; Proanthocyanidins; Seeds; Species Specificity; Tannins

Topics: Acacia; Animals; Comb and Wattles; Flavones; Proanthocyanidins; Tannins