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At least 19 recordsLinked to original sources
PubMed1975

[Interaction of yeasts with tannins. II. Study of various yeasts hydrolysing tannic acid in tannin culture media].

Growth and hydrolytic action on tannins of 6 strains of yeasts (isolated from tanning liquors and xylophagous insects) are studied in culture media containing various concentrations of tannic acid. The influence of medium acidity is also considered. According to the strains, growth is more or less restrained and hydrolytic activity is variable. Except for gallotannins, hydrolysable tannins are not hydrolysed.

Candida↗
PubMed1978

Investigations of leg abnormalities in chicks consuming high tannin sorghum grain diets.

Studies were conducted into the etiology of leg abnormalities noted in chicks fed high tannin sorghum grain diets. These anomalies were characterized by a bowing of the legs with a swelling of the hock joints. The incidence of these leg problems was found to be markedly higher when the amino acids in the diet provided by soybean meal were replaced by crystalline amino acids. Supplemental vitamins and minerals had no alleviating effect on the leg problem. Bone mineralization was apparently not influenced by tannins as demonstrated by similar bone ash values for chicks fed high or low tannin sorghums. A possible alteration caused by tannin in the organic matrix of bone is discussed. High tannin sorghum depressed chick growth and feed conversion when compared with low tannin sorghum in both sorghum-soybean meal and sorghum-amino acid rations. This growth depression was overcome by supplementing the high tannin sorghum-soybean meal diet with .15% DL-methionine, but no growth response was observed from a similar supplementation of a high tannin sorghum-amino acid diet.

Amino Acids↗
PubMed1992

The use of purified condensed tannin as a reference in determining its influence on rumen fermentation.

1. Tannins were purified from the leaves of trees forming part of giraffe's diet in the Kruger National Park. 2. In general, hydrolysable tannin formed less than 10% of the total purified crystal complexes, condensed tannin and possibly some non tannin phenols forming the balance. 3. Each tree species condensed tannin gave a different calibration curve and these were used in the assay. 4. Volatile fatty acid production during in vitro fermentation was greatly reduced when the substrate contained more than 6% condensed tannin.

Animals↗
PubMed1979

Protein quality in cereals and pulses. 3. Bioassays with rats and chickens on sorghum (Sorghum vulgare Pers.), barley and field beans (Vicia faba L.). Influence of polyethylene glycol on digestibility on the protein in high-tannin grain.

1. Two preceding papers in this series describe the application of microbiological and other in vitro tests in the evaluation of sorghum (Sorghum vulgare Pers.), field beans (Vicia faba L.) and barley, and in assessing the influence of polyethylene glycol (PEG 4000) on the nutritional availability of the methionine. The present paper gives for comparison the results of bioassays on some of the same test samples. Net protein utilization (NPU) in rats was measured by the nitrogen balance method, and N digestibility in chickens by the ileal analysis procedure. 2. In rat tests on sorghum, N in grain of high-tannin varieties was poorly digested. Supplementation of the test diets with 0.1 g PEG 4000/g protein gave a large improvemnet, which was partly offset by an apparent decrease in biological value (BV). With chickens N digestibility was even lower, and was similarly improved with PEG 4000. Treatment of high-tannin grain with ammonia solution was also effective in improving N digestibility. 3. With low-tannin sorghum the amino acid digestibilities were uniformly high and were not affected by addition of PEG to the test diet. With high-tannin sorghums they were low and less uniform, and were much improved by PEG 4000. 4. With field beans, the influence of the seed-coat tannin on protein utilization was much less pronounced than with sorghum. In chickens there was a significant effect (P less than 0.05) of PEG 4000 on N idgestibility in a high-tannin variety. With rats the effect was smaller and not significant. 5. In four samples of barley. N digestibility was high (0.87--0.96) and was not further improved by PEG 4000. The BV of a high-lysine cultivar proved marginally inferior to that of a normal variety. Possible reasons for this are discussed. 6. Over all, the results were closely consistent with those from microbiological tests with Streptococcus zymogenes.

Animals↗
PubMed1979

Immobilization of aminoacylase by adsorption to tannin immobilized on aminohexyl cellulose.

The immobilization of aminoacylase (N-acylamino acid amidohydrolase, EC 3.5.1.14) was investigated by using tannin immobilized on aminohexyl cellulose. The most active immobilized aminoacylase was obtained when aminoacylase was adsorbed to the immobilized tannin in a weak alkaline medium containing sodium chloride and n-butanol at 37 degrees C. The activity of the immobilized tannin-aminoacylase complex per unit volume was five times higher than that of the DEAE-Sephadex-aminoacylase complex used for industrial production of L-amino acids in our plants. The half-life of the immobilized tannin-aminoacylase complex was 20 days under continuous operation at a high concentration of substrate; on the contrary, that of the DEAE-Sephadex-aminoacylase complex was 0.5 days.

Adsorption↗
PubMed1979

Effect of peanut tannins on percent seed colonization and in vitro growth by Aspergillus parasiticus.

The relationship between tannin content of mature, intact, cured peanut seed and percent seed colonization by Aspergillus parasiticus was examined. Tannin content in 9 cultivars, 7 of which were grown in both Tifton, Georgia and Puerto Rico, was significantly correlated with percent seed colonization. For data expressed as mg tannin/g intact seed and mg tannin/g seed coat, correlation coefficients with percent colonization were 0.74 and 0.76, respectively. Seed coat tannin, methanol-extracted, water-soluble material from peanut seed coats, was tested in vitro for effects on growth of A. parasiticus. As concentrations of tannins were increased to 7.5%, inhibition of fungal growth increased linearly to 88%; a concentration of 20% produced over 96% inhibition.

Arachis↗
PubMed2025

Tannin-bearing hydrogel adhesives with enhanced mechanical and adhesion strength in response to protein leakage.

Anastomotic leaks are among the most severe side effects following abdominal surgeries. Conventional surgical sealants and emerging hydrogel adhesives often lose mechanical and adhesion strength when exposed to leaked digestive enzymes. Here, we report a tannin-encapsulating tough hydrogel adhesive that exhibits enhanced mechanical and adhesive properties upon the encounter of leaked proteins. The hydrogel is composed of a gelatin-acrylate crosslinked network with encapsulated tannin and can adhere to a wet surface via amine-carboxyl chemistry. In the context of anastomotic leaks, tannin within the hydrogel can form a complex with proteins including the digestive enzymes, leading to increased gel stiffness and storage modulus. The enhanced mechanical strength confers improved adhesive properties on the hydrogel adhesive. Additionally, the tannin-bearing hydrogel adhesive shows excellent antibacterial properties. This adaptive and antibacterial hydrogel adhesive provides a promising sealant for gastrointestinal surgery and other applications.

Tannins↗
PubMed1976

Identification of carcinogenic tannin isolated from Bracken fern (Pteridium aquilinum).

We attempted to isolate a carcinogenic substance from bracken fern (Pteridium aquilinum), a naturally occurring toxicant responsible for the production of chronic enzootic hematuria and urinary bladder cancer of cattle and carcinogenic for various target organs of several species. Hot methanol extracts of bracken fern were solubilized in water and extracted with chloroform followed by a mixture of n-butanol-butanone (1:1). That fraction was dried and triturated with ether-methanol (4:1), n-butanol, and finally absolute ethanol. The insoluble residue was dissolved in 10% aqueous methanol and passed through Dowex 1 OH-, Dowex 50 H+, or Dowex 1 OH- and then Dowex 50 H+ ion exchange resins. A condensed tannin, isolated from one ot the fractions, was identical to that isolated from bracken fern by the caffeine procedure used for the separation of tannins from other plant constituents. Three systems were used for bioassay; induction of bladder carcinoma by implantation of cholesterol pellets containing bracken fern fractions into the bladder lumens of mice; acute toxicity by ip injection of brachen fern fraction into mice; and growth inhibition of Escherichia coli. The following fractions induced significantly greater incidences of bladder carcinoma than did cholesterol pellets only: tannin, Dowex 50 H+, residue, n-butanol, and methanol. Tiliroside, a component of bracken fern fractions into the bladder lumens of mice; acute genic acid, and quercetin were not carcinogenic. Tannin was the most toxic (mean lethal dose: 0.16 mg/g) and carcinogenic. None of the carcinogenic fractions inhibited growth of E. coli.

Escherichia coli↗
PubMed1975

[Comparative study of different extraction methods and assays of tannins in some pteridophytes].

Various processes of extraction and quantitative analysis of a condensed tannin in a plant extract, which also includes some chlorogenic acids, have been examined. 60% methanol, at 50 degrees C, proved the most efficient extraction solvent. Several methods of analysis have been tried. The measure of the colour intensity obtained by the action of sulphuric vanilline on flavanols cannot be used because it depends on the tannin condensation stage. It is impossible to separate tannin from chlorogenic acids using the methods of adsorption by skin or nylon powders, or precipitation by polyvinylpyrrolidone. Only paper chromatography, followed by the distinct elution of the various phenolic compounds, allows the tannin evaluation by subtraction; but owing to the variability of the results, many more experiments are necessary. Some other processes are being studied.

Chlorogenic Acid↗
PubMed1976

[Effect of prolonged glucidic starvation on the contents of starch and tannins of Blechnum brasiliense L. gametophytes].

Some Blechnum brasiliense gametophytes have been maintained in darkness, in a purely mineral medium, for the purpose of investigating the effect of prolonged glucidic starving on the amount of tannins and starch that they contain. During the first two months the tannin contents undergoes a fast decrease. The starch variations are different : a transitory increase simultaneous with the fall in tannin; a decrease after the disappearance of 3/4 of the tannin contents; and lastly, a new amylogenese which precedes the prothallus necrosis. It seems that the gametophytes, in order to survive, degrade first their tannoidic reserves, and they utilize the starch that they contain only with difficulty. This behaviour can be explained by the distribution of the two metabolites; by the acid pH of the medium, which is not very propitious to the phosphorylases activity and lastly by the presence of chlorogenic acids, which are inhibitors of those enzymes.

Cells, Cultured↗
PubMed2025

WRKY14-DPB Module Enhances Drought Tolerance by Activating the Expression of UGT84B1 Involved in Hydrolyzable Tannin Biosynthesis.

Drought stress severely limits the growth and development of trees. Tannins, which serve as vital secondary metabolites in plant roots, help mitigate drought stress. The Lauraceae family, which holds major economic and ecological value, faces substantial developmental challenges due to its sensitivity to drought conditions. Despite this, research on the regulatory mechanisms governing tannin-specific accumulation under drought stress remains limited. In this study, we aim to explore how WRKY14 interacts with DPB to regulate the metabolism of hydrolyzable tannin (HT) via the key enzyme UGT84B1, thereby enhancing drought tolerance in Litsea cubeba, a main species within the Lauraceae family. The WRKY-DPB-UGT84B1 module was specifically expressed in roots in response to drought stress. LcUGT84B1 was found to generate 1-O-Galloyl-β-d-glucose in vitro and in overexpressing L. cubeba. Moreover, molecular biology and transformation experiments demonstrated that LcWRKY14 and LcDPB formed a complex that directly bound to the LcUGT84B1 promoter, activating its expression and thereby facilitating HT synthesis. Co-overexpression of LcWRKY14 and LcDPB significantly enhanced drought tolerance by increasing HT accumulation. These findings provide new insights into the regulatory mechanisms of the WRKY-DPB-UGT84B1 module in promoting drought tolerance and offer a potential breeding strategy for developing drought-resistant varieties.

Drought Resistance↗
PubMed1975

Vanillin-hydrochloric acid as a histochemical test for tannin.

Condensed tannin (leucoanthocyanins and catechins) can be demonstrated in fresh plant sections with saturated alcoholic vanillin followed by addition of concentrated HCl. Bright red vanillin-tannin condensates are formed immediately. Preparations may then be made permanent by mounting in a 1:1 mixture of Hoyer's medium and concentrated HCl. Some fading and loss of tannin occurs. The phloroglucinol-HCl test for lignin can also be made permanent with this acidic mountant.

Flavoring Agents↗
PubMed1976

Differential staining of tannin in sections of epoxy-embedded plant cells.

A staining procedure is described for the light microscopic localization of ergastic tannins in epoxy sections of plant cells embedded for study by transmission electron microscopy. Callus and cell suspensions of Pseudotsuga menziesii and Pinus taeda fixed in glutaraldehyde:acrolein and then OsO4, followed by epoxy embedding, were sectioned 0.5 mum thick, stained on a glass slide with ethanolic Sudan black B at 60 C as described by Bronner, and then mounted in Karo syrup. Tannin deposits stained brownish-orange and were easily distinguished from lipid bodies of similar size, which stained dark blue to black, and from starch grains, which were unstained. The significance of this differential polychromasia was confirmed by transmission electron microscopy. This staining procedure should prove valuable in the cytoplasmic evaluation of the plant cell ergastics (especially tannins) via light microscopy whether or not electroc microscopic examination is intended.

Plant Cells↗
PubMed1976

Partial purification of nucleopeptides from rabbit skeletal muscle by the tannin-caffeine procedure.

After precipitation of acid-soluble proteins from sulfosalicylic acid extracts of rabbit skeletal muscles with tannin at neutral pH, the remaining material still formed insoluble complexes with tannin. After removing tannin with caffeine complexes subjected to column chromatography on Dowex 1 x 8 gave four fractions containing both amino acids and nucleotides. It was concluded that the isolated material contains nucleopeptides, besides nucleotides.

Amino Acids↗
PubMed1976

Carcinogenicity of Camellia sinensis (tea) and some tannin-containing folk medicinal herbs administered subcutaneously in rats.

In an attempt to correlate the high incidence of esophageal carcinoma in natives of certain places with their habit of using herbaceous folk medicines, we performed bioassays of several plant extracts and the fractions prepared from them. Fourteen extracts and fractions from 6 plants were injected sc into NIH Black rats. The tannin fractions from Quercus falcata pagodaefolia, Diospyros virginiana, and Camellia sinensis were very active and produced tumors at the injection site in 66% or more of the treated animals. Tannin fractions from 3 other plants and total aqueous extracts from 5 to 6 tested plants were also tumorigenic rats. The induced tumors were malignant fibrous histiocytomas similar, if not identical, to those encountered in humans. The experiment indicated a possibility of induction of tumor in man by the tested plant materials.

Animals↗
PubMed1976

Microbial degradation of condensed tannins.

A strain of Penicillium adametzi Zaleski was isolated from enrichment cultures with condensed tannins as the carbon source. Low-molecular-weight condensed tannins, extracted and purified from Pinus radiata bark, were used as substrates for quantitative growth measurements on this fungus in defined culture conditions.

Penicillium↗