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At least 577 records · Page 32Linked to original sources
PubMed1998

[Studies on tannins from Tripterygium hypoglaucum (lévl.) hutch].

OBJECTIVE: To study the tannins from Tripterygium hypoglaucum. METHOD: Compounds were isolated by column chromatography and elucidated on the basis of spectroscopic analysis and comparison of references. RESULT: The compounds obtained were determined as (+)catechin, (-)epigallocatechin, procyanidin B-3, procyanidin B-4 and gallocatechin-(4 alpha-->8) epicatechin. CONCLUSION: All the compounds were obtained from this plant for the first time.

Biflavonoids↗
PubMed1975

[Molecular aspects of the interaction of albumin and tannined erythrocytes in the process of hemosensitization. II. The effect of temperature].

A study was made of a combined influence of the temperature of the medium and of sensitin concentration on the process of interaction of tannin-treated sheep erythrocytes and human serum albumin. On the basis of determination of the number of molecules bound by a single erythrocyte during hemosensitization,, depending on the mentioned conditions, it was revealed that the relative total albumin binding increased with the elevation of temperature. Elevation of temperature also led to the absolute and the relative increase in the stable and a reduction in the loose albumin binding by a single erythrocyte and the growth of sensitivity of the passive hemagglutination test. The role of chemical mechanisms in the erythrocyte albumin loading was demonstrated; this permitted to carry out erythrocyte albumin sensitization at a comparatively high temperature for the purpose of increasing the efficacy of passive hemagglutination test.

Erythrocytes↗
PubMedDate not supplied

[Determination of tannins in the rhizomes of Potentilla tormentilla].

A modified permanganometric method for determination of tannin in tormentile rhizome is proposed. The results compared with values obtained by the regulations of Ph Yug II, Ph Yug III, Ph Yug IV and DAB 9 are reproducible and the method is fast and simple.

Plants, Medicinal↗
PubMedDate not supplied

[Tannin and gallic acid as marker of exposure to hardwood dust].

The total tannin concentration was determined, using two different SPF methods, in 35 dust powdered wood species, both hard and softwood. Using direct reading-method (280 nm) the concentration varied from 2485 mg/g for Swedish pine to 35,843 mg/g for European oak (quercus robur, hardwood). The data obtained with the second method (Folin-Chocalteau) were well correlated (y = 0.9885x + 4.3373; r = 0.84; n=35) with the data obtained with the first method. The measured concentrations are usually higher in hardwood than softwood tested. Finally, a simple HPLC-DAD method was tested for gallic acid (GA), recently proposed as a marker for oak dust.

Air Pollutants, Occupational↗
PubMed1990

The tannin-osmium conductive staining after dehydration: an attempt to observe the chromosome structure by SEM without metal coating.

The tannin-osmium conductive staining method was modified in order to observe chromosomal structures without metal coating. The treatment with tannic acid and OsO4, which has been used in aqueous solution in the original method, was performed in acetone solution after dehydration in the present study. The usefulness of this method is discussed showing ultrastructural images of chromosomes of Drosophila and Tradescantia, which can be achieved by the method.

Animals↗
PubMed1990

The effect of tannin treatment and subsequent urea supplementation of sunflower meal on the in vitro digestibility of its crude protein for ruminants.

The effect of tannin treatment (TSFM) and subsequent urea supplementation (TSFM + U) on the digestibility of sunflower meal (SFM) protein was studied by means of a three-phase laboratory method simulating the ruminant's digestion. Under the influence of the ruminal fluid 67% of SFM protein, 62% of TSFM protein and 58% of TSFM + U protein was degraded. The pepsin and pancreatin digestibilities of rumen undegraded protein (UDP) were as follow: 58.2% (SFM), 56.6% (TSFM), 43.3% (TSFM + U), and 22.0% (SFM), 28.8% (TSFM), 17.5% (TSFM + U), respectively. The four fractions (dissolved protein, oligopeptides, amino acids, and ammonia) of rumen degradable protein (DP) were also determined: 85 to 92% of rumen degradable protein was recovered in these four fractions. Owing to tannic acid treatment the quantity of dissolved protein decreased and that of oligopeptides increased.

Animal Feed↗
PubMed1987

Quantitative analysis of areca catechu (betel) nut flavanols (tannins) in relation to oral submucous fibrosis.

The processed areca catechu (betel) nuts are popularly chewed in the Indian sub-continent. The significance of areca flavanol (tannin) in relation to oral submucous fibrosis and oral carcinogenesis has been reviewed. The quantitative analysis of ten different commercial nut samples from Bombay, India showed wide variations and a higher than average content of flavanols. These variations reflect their appeal and also influence the predisposition of these diseases. The incidence of oral submucous fibrosis and the nut flavanol contents from Bombay and Kerala were taken for comparisons.

Humans↗
PubMed1978

[Molecular parameters of sensitization of tannin-treated erythrocytes with Salmonella d-flagellin].

A study was made of the molecular parameters of sensitization of tannin-treated sheep red blood cells with salmonella d-flagellin, depending on the protein dose, exposure, and temperature of the medium; the role played in this process by physical and chemical mechanisms was ascertained, the latter proving to determine the hemosensitization level. Senstivity of the erythrocytic diagnostic agent to the agglutinating action of the specific serum was maximal with a stable binding by a single red blood cell of about 200 000 flagellin molecules, although the limit of stable binding constituted 340 000 molecules per one red blood cell. On condition of saturation limit of the erythrocyte flagellin should block not over half of the cell surface. The temperature elevation during the diagnostic agent preparation is advantageous in technological respect, since it leads to reduction of flagellin expenditure and increases the sensitivity of the passive hemagglutination tests.

Animals↗
PubMed1982

[Role of cell-surface protein screening and the determinant of the other sensitin in polyvalent sensitization of tannin-treated erythrocytes].

On the strength of the data obtained in the study of the successive loading of tannin-treated red cells with two protein antigens (with the use of 12 different models) the limiting role of two factors in comparison with monovalent sensitization has been revealed. When a red blood cell is previously loaded with one protein, the possibilities of binding the second protein decrease due to the reduction of the available cells surface. Besides, both these proteins bound to the red blood cell screen each other by creating steric obstacles to the interaction of the protein determinants with antibodies. Such steric obstacles suppress, to a lesser extent, the association of the bound proteins with antibodies and, to a greater extent, the agglutination of antibodies with sensitized red blood cells.

Animals↗
PubMed1993

Obturation of dentinal tubules with tannin-fluoride preparation (HY agent) incorporated into glass ionomer cement.

The degree of obturation of dentinal tubules as well as the dentinal uptake of F, Zn and Sr was investigated after placement of glass ionomer cement (GIC) containing variable proportions of the tannin-fluoride preparation, HY agent, into freshly prepared cavities. It was found that when HY agent was incorporated into the cement powder, there was both increase in electrical resistance in the dentinal floor of the GIC-restored cavity in addition to inhibition of dye penetration. Further, these changes were directly proportional to the concentration of HY agent. Electron probe microanalysis of the principal constituents of HY agent (F, Zn and Sr) revealed that the penetration depth for F and Zn was also directly proportional to the relative amount of incorporated HY agent, whereas Sr could not be detected regardless of HY concentration. Results clearly demonstrated that the higher the concentration of HY agent incorporated into GIC, the greater the degree of dentinal tubular obturation.

Animals↗
PubMed1993

Effects of rhubarb tannins on renal function in rats with renal failure.

The effects of tannins purified from Rhei Rhizoma on various parameters of renal function were investigated in rats with adenine-induced renal failure. The glomerular filtration rate, renal plasma flow and renal blood flow were significantly increased in rats given (-)-epicatechin 3-O-gallate at a dose of 5 or 10 mg/kg body weight/day for 24 days. Administration of 5 mg of procyanidin B-2 3,3'-di-O-gallate also led to a significant increase in renal functional parameters. However, unlike the former two components, procyanidin C-1 3,3',3''-tri-O-gallate caused aggravation of renal function.

Adenine↗
PubMed1993

[Tannin-mediated attachment of avidin to erythrocytes does not cause their lysis by complement].

It was shown previously that avidin attachment to biotinylated erythrocytes induced their lysis by a homologous complement via an alternative pathway. This phenomenon hindered the use of avidin-coated immuno-erythrocytes as carriers for drug targeting. In the present work it has been demonstrated that avidin attachment to erythrocytes via a cross-linking reagent (tannin) does not induce any lysis by the complement. Tannization provides an attachment of up to 5 x 10(5) avidin molecules per erythrocyte which is commensurate with the value obtained after treatment with biotin esters. However, in contrast with biotinylated avidin-coated erythrocytes tannized cells are not lysed by the complement, while tannization itself does not diminish the erythrocyte sensitivity to lysis by the complement in the presence of activators (hemolytic antibody or activators of the alternative pathway). The avidin-induced lysis by the complement depends on the mode of avidin attachment to erythrocytes. Complement-resistant avidin-coated tannized erythrocytes bind biotinylated immunoglobulins and may therefore be used as carriers for drug targeting. The use of hemolytic antibody in biotinylated immunoglobulins attached to avidin-coated erythrocytes provides their controlled lysis by a complement activated via a classical pathway.

Avidin↗
PubMed1976

[Molecular parameters of the sensitization of tannined erythrocytes with human IgG].

A study was made of the molecular binding parameters during the sensitization of human IgG with tannin-treated sheep erythrocytes, depending on the concentration of the reacting components. The total amount of IgG molecules stably bound by all erythrocytes increased with the elevation of erythrocyte and IgG concentration. About 1.7 million IgG molecules were stably fixed on one erythrocyte under conditions providing the maximum binding. However, the level of hemosensitization approaching the maximum was provided by binding 400,000--600,000 IgG molecules by one erythrocyte. Apparently the level of specific IgG sensitization was determined not only by the amount of protein molecules stably bound by one erythrocyte, but also by the character of space position of the IgG molecules on the erythrocyte surface.

Binding, Competitive↗
PubMed2005

Characterization of condensed tannins purified from legume forages: chromophore production, protein precipitation, and inhibitory effects on cellulose digestion.

To identify simple screening tools for selecting condensed tannin (CT)-containing forages as candidate sources for further study, CT were isolated from nine legumes, and their molecular weights (MW), chromophore production, capacity to precipitate bovine serum albumin (BSA) and Fraction 1 protein (Rubisco) isolated from alfalfa, and inhibition of filter paper digestion were compared. Sources were as follows: leaves of sericea lespedeza (Lespedeza cuneata Dum.-Cours.), crown vetch (Coronilla varia L.), and sainfoin (Onobrychis viciifolia Scop.); stems of hedysarum (Hedysarum alpinum L.); seeds of alfalfa (Medicago sativa L.); and whole plants of birdsfoot trefoil (Lotus corniculatus var. corniculatus L.) and three varieties of big trefoil (Lotus pedunculatus Cav.), viz., Lotus uliginosus Schkuhr, L. uliginosus var. glabriusculus, and L. uliginosus var. villosus. Molecular weights and sizes (degrees of polymerization) of the CT varied considerably within and among plant species. Average MW ranged from 3036 Da (crown vetch) to 7143 Da (lespedeza). All CT exhibited greater capacity (w/w basis) to bind alfalfa Rubisco than BSA. Relative astringencies (microg CT required to precipitate 1 mg protein) against BSA ranged from 262.5 for CT from lespedeza to 435.5 for CT from L. corniculatus, and against Rubisco, from 49.6 (sainfoin) to 108.2 (alfalfa seed). Including CT at 300 microg/ml in cultures of Fibrobacter succinogenes reduced digestion of cellulose filter paper by 19.8% (sainfoin) to 92.4% (crown vetch) and increased the specific activity of cell-associated endoglucanase. There were no correlations between inhibitory effects of CT on filter paper digestion and (1) chromophore formation during CT assay by butanol-HCl, vanillin-HCl, or H2SO4; (2) precipitation of BSA or alfalfa Rubisco; and (3) MW of CT. The most inhibitory CT for cellulose digestion included those with broad and with narrow MW distributions. Sainfoin was the most desirable source of CT, as it had the highest capacity to bind alfalfa protein and was least inhibitory to cellulose digestion by F. succinogenes. This study suggests that these properties are not easily defined via chemical means, and that biological assays using rumen bacteria may help identify those CT with properties of nutritional interest.

1-Butanol↗
PubMed2005

The effect of grazing forage containing condensed tannins on gastro-intestinal parasite infection and milk composition in Angora does.

The objective of this study was to evaluate effects of the condensed tannin (CT)-containing forage sericea lespedeza (sericea lespedeza (SL); Lespedeza cuneata; 15.2% CT), on fecal egg count (FEC), larval development (larvae/10 g of feces), worm burden and immune response compared with a crabgrass (Digitaria ischaemum)/Kentucky 31 tall fescue (Festuca arundinacea; control forage (CTF)) forage low in CT (0.32% CT) in grazing Angora does and their kids. Fifty worm-free mixed-age does were randomly allocated to three treatments. One treatment (10 does; initial liveweight (LW) = 45+/-1.5 kg) entailed grazing of SL forage from April 25 to July 15, 2002 with a second treatment of CTF (20 does; initial LW = 43+/-1.4 kg) grazing during the same period. Does of the third treatment (20 does; initial LW = 44+/-1.4 kg) grazed a sward of SL for 2 weeks and then one of CTF for 2 weeks followed by alternating between the two pastures every 2-week rotational grazing (ROT). To gauge levels of infective larvae on pasture, three worm-free Angora kids (initial LW = 3.6+/-0.2 kg) were randomly selected as tracers. Tracers grazed for final 60 days and were euthanized for determination of worm burden. The immune response of does was measured by skin thickness reaction after the intradermal injection of 250 microg phytohemagglutinin (PHA). Mean FEC for SL and ROT were substantially lower (P < 0.01) than for CTF does (145, 329 and 894 eggs/g, respectively). The FEC for kids was lower (P < 0.05) for SL than for ROT and CTF (550, 2757 and 3600 eggs/g, respectively). Total fecal egg output (3.3, 6.0 and 26.9 x 10(5) eggs/day, respectively) and larval development (242, 263 and 792 larvae/10 g, respectively) were lower (P < 0.05) for SL and ROT than for CTF. Tracers grazing on SL had lower total worm burdens than ROT and CTF (P < 0.01). The immune response was higher (P < 0.01) for SL (4.9 mm) and ROT (6.0 mm) than for CTF (3.0 mm) at 12 h after injection of PHA. The packed cell volume (PCV) in does was higher (P < 0.01) for SL and ROT than for CTF (27, 26 and 23%, respectively). Does that grazed CT-containing forage had considerably lower milk somatic cell counts (SCC) than does grazing non-CT-containing forage. In summary, grazing CT forages reduced FEC, larval development and worm burden, and also appeared to enhance immune response. The CT-containing forage SL reduced gastro-intestinal parasite infections of Angora does and kids.

Animal Feed↗
PubMed2001

Encapsulation of tannase for the hydrolysis of tea tannins.

Tannase was encapsulated in alginate, chitosan, carrageenan or pectin gel matrices, and in the case of alginate, coated with high or low molecular weight chitosan to reduce enzyme release. Cross-linking with glutaraldehyde also improved enzyme retention. Active enzyme preparations were obtained, although carrageenan gels were unstable in tea. Tannase activity was evaluated by reduction in centrifugable (flocculated) tea solids, and a reduction in tea cream measured turbidimetrically after removal of flocculated solids. Tannin interactions with the polysaccharide gels increased the level of centrifugable solids (flocculent) in the tea. An optimum bead formulation consisted of an alginate core, coated with chitosan and cross-linked with glutaraldehyde. Both core and coating materials contained active enzyme. Beads were prepared in a single step procedure involving extrusion of alginate/tannase solution into a hardening bath containing tannase-loaded, chitosan solution. Tannase retained hydrolytic activity through three successive batch cycles, for a total period of 39h processing, and tea cream was visibly removed by treatment with the immobilized tannase. Activity remained stable during 1-month bead storage under refrigeration.

Journal Article↗
PubMed1997

Removal of lignin and tannin colour from aqueous solution by adsorption onto activated charcoal.

Sorptive uptake of lignin and tannin from an aqueous phase by activated charcoal was investigated in the laboratory. The sorption reaction was found to be of a first order. The influence on the rate of sorption of various factors, such as amount of sorbent and pH of the system, have been investigated. Sorption data fit well into the Langmuir adsorption isotherm, indicating formation of a monolayer over a homogeneous sorbent surface. Sorption capacity, rate constant, intraparticle diffusion coefficient, etc. were calculated from the sorption data. Desorption studies indicate the irreversible nature of the sorption reaction, whereas interruption studies suggest film diffusion to be rate limiting.

Journal Article↗