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PubMed1999

[Studies on tannin and hydrolysate in three species of Chinese Caesalpinia plants].

OBJECTIVE: To get Chinese Caesalpinia plants that can replace the imported Tara to produce tannin and gallic acid. METHOD: Extract tannin with water, condense and hydrolyze the extracts with alkali, the hydrolysates were identified. Furthermore, an enlarged scale experiment was conducted. RESULT: Tannin contents of the plants were 32.2%, 46.6% and 58.5% respectively, the converted ratios of raw material to hydrolysate were 154:1, 11.8:1, 3.09-2.79:1 respectively. CONCLUSION: We got the Tara-replacing plants in Chinese Caesalpinia plants for the first time.

Caesalpinia↗
PubMed1991

Effects of chemically defined tannins on poly (ADP-ribose) glycohydrolase activity.

Three classes of chemically defined tannins, gallotannins, ellagitannins and condensed tannins were examined for their inhibitory activities against purified poly (ADP-ribose) glycohydrolase. Ellagitannins showed higher inhibitory activities than gallotannins. In contrast, condensed tannins, which consist of an epicathechin gallate (ECG) oligomer without a glucose core were not appreciably inhibitory. Kinetic analysis revealed that the inhibition of ellagitannins was competitive with respect to the substrate poly(ADP-ribose), whereas gallotannins exhibited mixed-type inhibition. These results suggest that conjugation with glucose of hexahydroxy-diphenoyl (HHDP) group, which is a unique component of ellagitannins, potentiated the inhibitory activity, and that the structure of ellagitannins may have a functional domain which competes with poly(ADP-ribose) on the poly(ADP-ribose) glycohydrolase molecule.

Glycoside Hydrolases↗
PubMed1988

Evaluation of the contribution of tannin to the acute pulmonary inflammatory response against inhaled cotton mill dust.

Anesthetized, intubated, and mechanically ventilated rabbits were exposed to aerosolized saline, cotton dust extract (CDE), or tannin for 5 minutes and lavaged 4 hours after exposure. Cell numbers and types present in the bronchoalveolar lavage fluid (BALF) were determined and the concentrations of thromboxane A2 (TxA2) and prostaglandin F2-alpha (PGF2-alpha) in the BALF were also analyzed. The saline control animals had increased numbers and percentage of polymorphonuclear leukocytes (PMN) in the BALF as well as increased levels of TxB2 and PGF2-alpha compared with unexposed animals. Exposure to CDE further increased the number and percentage of PMN and the level of PGF2-alpha but had no effect on TxA2 levels when compared with control animals. Tannin exposure increased PGF2-alpha levels to the same extent as CDE exposure. PMN also increased but to a lesser extent than with CDE. These results indicate that the inflammatory response to CDE is only partially due to the tannin present in CDE.

Animals↗
PubMed1984

Platelet 5-hydroxytryptamine release and aggregation promoted by cotton bracts tannin.

The effect of aqueous extracts of cotton bract (CBE) on platelet secretion and aggregation was examined by using washed bovine and human platelets. The CBE promoted the release of 75% to 90% of the 5-hydroxytryptamine (5-HT) stored in both human and bovine platelets in a dose-dependent manner. This release reaction occurred without the lysis of the platelets and was not inhibited by indomethacin, 2-deoxyglucose, or KCN. Fractionation of the CBE indicated that the platelet secretagogue present in the CBE was the condensed polyphenol, tannin. In addition to promoting the secretion of 5-HT, tannin also aggregated the platelets in a dose-dependent manner. We conclude that the secretion of platelet 5-HT and the aggregation of platelets by tannin could potentially contribute to the pulmonary symptoms associated with byssinosis.

Animals↗
PubMed1995

"In vitro" effect of Egyptian tannin-containing plants and their extracts on the survival of pathogenic bacteria.

This study was conducted on leaves from tannin containing plants which are widely spread in Upper Egypt. From two plants also fruits were investigated (A. nilotica and A. farnesiana). One of the objectives was to determine the total soluble polyphenols and the soluble condensed tannins of these plants. Furthermore the assumed antimicrobial effect of A. nilotica and A. farnesiana leaves and their extracts on C. perfringens, E. coli and S. typhimurium was studied "in-vitro" at dilutions of 0.5% and 0.05%. The tests were carried out in physiological saline solution and in rumen fluid medium (RFM). The results revealed that the total soluble polyphenols ranged from 10.27% to 35.46% and the condensed tannins from 0.5% to 8.28% on dry matter base. The antimicrobial effect of the plant material was only observed on C. perfringens but not on E. coli and S. typhimurium. A. nilotica leaves destroyed the suspension of C. perfringens immediately after being added. Leaves from A. farnesiana showed a delayed affect. Plant extracts were less effective than the raw plant material. In RFM A. nilotica leaves destroyed the bacterial suspension after 10 minutes only at the concentration of 0.5%, but not at 0.05%. With A. farnesiana at a concentration of 0.5% only a reduction was observed. The concentration of 0.05% had no influence. The presence of other proteins than bacterial suspension in rumen fluid (rumen bacteria, protozoa and plant proteins) inhibits the antimicrobial effect of the plant material in a concentration of 0.05%, but not at 0.5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Acacia↗
PubMedDate not supplied

[The cytotoxicity of Chamaenerium angustifolium (L.) Scop. and Hippophae rhamnoides L. tannins and their effect on mitochondrial respiration].

The cytotoxic activity of complexes of hydrolysable tannins of Chamaenerium angustifolium L. Scop. and Hippophae rhamnoides L. was compared with that of the antineoplastic drugs vinoblastin (VLB), methotrexate (MT), and 5-fluorouracil (5-FU). The tannins yield to VLB and MT in activity but resemble 5-Fu in their active concentration. They inhibited succinate oxidation by the rat liver mitochondria and their cytotoxicity was displayed in much lower concentrations than their inhibitory effect on mitochondrial respiration. It is concluded that tannins inhibit the respiratory chain at the third point of conjugation in the transfer of electrons from cytochrome c to oxygen.

Animals↗
PubMed1997

Tannin elimination and improvement of the digestibility of protein sorghum grains.

Three hybrids of sorghum grains [Sorghum bicolor (L) Moench] containing 3.8, 3.0 and 0.2% of tannins were treated. Abrasive dehulling and storage of moist grains were tested separately and in combination to reduce the tannin content and to improve the nutritional quality of grains. The moisture content of the grains was increased from 12 to 30% by humidifying them with water, acetic acid, sodium bicarbonate or sodium hypochlorite solutions. Abrasive dehulling of the grains to a yield between 75 and 80%, humidifying the grains with acetic acid (1% v/v) and storing them during 7 days at 20 degrees C proved to be the most effective procedure. In this way tannin can be totally reduced and the in vitro digestibility of protein can be increased to 87.5%.

Digestion↗
PubMed1998

Tannin-tolerant ruminal bacteria from East African ruminants.

Three strains of tannin-tolerant rumen bacteria were isolated from enrichment cultures of rumen microflora of sheep, goat, and antelope and established in medium containing high concentrations of crude tannin extract or tannic acid. These three strains (EAT2, ES3, and EG19), characterized as Selenomonas species, were curved rods, obligately anaerobic, Gram negative, highly motile, and grew in media containing 50 g of tannin extract/L and 50-70 g of tannic acid/L. Strain EAT2 was able to hydrolyze gallic acid, while strains ES3 and EG19 hydrolyzed tannic acid but not gallic acid. All isolates were able to grow in media containing up to 8 g of condensed tannins/L. Growth was very slow when soluble carbohydrate was not added to the medium.

Anaerobiosis↗
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↗
PubMed1995

Characterization of tannin acylhydrolase activity in the ruminal bacterium Selenomonas ruminantium.

A strain of the anaerobe Selenomonas ruminantium subsp. ruminantium that is capable of growing on tannic acid or condensed tannin as a sole energy source has been isolated from ruminal contents of feral goats browsing tannin-rich Acacia sp. Growth on tannic acid was accompanied by release of gallic acid into the culture medium but the bacterium was incapable of using gallic acid as a sole energy source. Tannin acylhydrolase (EC 3.1.1.20) activity was measured in crude cell-free extracts of the bacterium. The enzyme has a pH optimum of 7, a temperature optimum of 30-40 degrees C and a molecular size of 59 kDa. In crude extracts, the maximal rate of gallic acid methyl ester hydrolysis was 6.3 micromol min(-1) mg(-1) of protein and the K(m) for gallic acid methyl ester was 1.6 mM. Enzyme activity was displayed in situ in polyacrylamide and isoelectric focusing gels and was demonstrated to increase 17-fold and 36-fold respectively when cells were grown in the presence of gallic acid methyl ester or tannic acid.

Journal Article↗
PubMed2001

Effect of polyethylene glycol on rumen volume and retention time of liquid and particulate matter along the digestive tract in goats fed tannin-rich carob leaves (Ceratonia siliqua).

The present work studied the effects of tannins in carob leaves (CL) on rumen volume and kinetics, and on the retention time of fluid and particulate components of the digesta along the gastrointestinal tract (GIT) in goats. The experimental design was a two factor crossover experiment, i.e. in phase 1, two goats were fed CL and 2 CL and polyethylene glycol (PEG) and in phase 2, the treatments were switched. The main effects of tannins were depression of the rumen fluid and particulate content of the rumen, acceleration of the passage of liquid from the abomasum, and delay of the passage of digesta in the intestine. The overall effect was a delay in the passage of fluid and particulate matter throughout the entire GIT. It is hypothesised that these responses are largely the consequence of the interaction of tannins with digestive enzymes and the epithelium lining of the digestive tract.

Journal Article↗
PubMed2003

Three-dimensional structure and dynamics of wine tannin-saliva protein complexes. A multitechnique approach.

The interactions between the B3 (catechin-4alpha,8-catechin) red wine tannin and the human salivary protein fragment IB7(14) (SPPGKPQGPPPQGG) were monitored by (1)H magic angle spinning NMR, circular dichroism, electrospray ionization mass spectrometry, and molecular modeling. It is found that the secondary structure of IB7(14) is made of a type II helix (collagen helix) and random coil. The central glycine 8 appears to act as a flexible rotula separating two helix II regions. Three tannin molecules tightly complex the peptide, without modifying its secondary structure, but seem to reduce its conformational dynamics. The binding dissociation constant is in the millimolar range. B3 tannins with a "tweezers" conformation bind to the hydrophilic side of the saliva peptide, suggesting that the principal driving forces toward association are governed by hydrogen bonding between the carbonyl functions of proline residues and both the phenol and catechol OH groups. These findings are further discussed in the frame of an astringency phenomenon.

Anthocyanins↗
PubMed1994

Effects of Sainfoin (Onobrychis viciifolia Scop.) Condensed Tannins on Growth and Proteolysis by Four Strains of Ruminal Bacteria.

Sainfoin leaf condensed tannins inhibited growth and protease activity in Butyrivibrio fibrisolvens A38 and Streptococcus bovis 45S1 but had little effect on Prevotella ruminicola B(1)4 or Ruminobacter amylophilus WP225. Tannins bound to cell coat polymers in all strains. Morphological changes in B. fibrisolvens and S. bovis implicated the cell wall as a target of tannin toxicity.

Journal Article↗
PubMed1993

[Evolution of phenolic compounds and condensed tannins (Proanthocyanidins) during the development of bean seeds (Phaseolus vulgaris L.)].

The evolution of phenolic compounds and tannins (proanthocyanidins) of bean seeds, Phaseolus vulgaris L., (cultivar aroana 80), from anthesis to maturity (10 to 45 days after anthesis), was investigated. During seed development, phenolic compounds and tannins contents increased by seed unit, until the 31st and 21st day after anthesis respectively, decreasing afterwards. The gradual decrease in catechin and the increase of its polymers (intermediate compounds), as well as the gradual increase in alpha-amylase inhibition capacity were indications that tannins polymerize during seed development.

Anthocyanins↗
PubMed1994

A dimeric hydrolysable tannin from Camellia oleifera.

Camellioferin A, a new dimeric ellagitannin, was isolated, together with 13 known tannins, including camellins A and B, from Camellia oleifera. The structure of the new tannin elucidated by spectroscopic methods.

Circular Dichroism↗
PubMed2005

Suppression of tumor cell invasiveness by hydrolyzable tannins (plant polyphenols) via the inhibition of matrix metalloproteinase-2/-9 activity.

Elevated expression of matrix metalloproteinases (MMPs), especially that of MMP-2 and MMP-9, is associated with increased metastatic potential in many tumor cells. Recently, green tea polyphenol epigallocatechin-3-O-gallate (EGCG) has been shown to inhibit the MMP-2/-9 activity as well as the invasiveness of tumor cells. In this study, we have examined the inhibitory effect of hydrolyzable tannins (plant polyphenols) on the tumor cell invasion. Our results demonstrate that beta-d-glucose whose hydroxy groups are substituted entirely with galloyl group and further some of them are cross-linked to form hexahydroxydiphenoyl group, for example, suppresses the invasiveness of tumor cells much more potently than EGCG via direct inhibition of the MMP-2/-9 activity. Among those examined, 1,2,4-tri-O-galloyl-3,6-hexahydroxydiphenoyl-beta-d-glucose (punicafolin) inhibits the invasion of HT1080 fibrosarcoma cells most potently. These hydrolyzable tannins would provide new leads for the development of potent inhibitors against tumor metastasis.

Animals↗
PubMed2006

Analysis of condensed and hydrolysable tannins from commercial plant extracts.

High performance liquid chromatography (HPLC)/DAD and MS qualitative and quantitative analyses of polyphenols, hydrolysable and condensed tannins from Pinus maritima L. and tannic acid (TA) extracts were performed using normal and reverse phase. Normal-phase HPLC was more suitable for pine bark (PBE) and tannic acid extracts analysis. The chromatographic profile revealed that P. maritima L. extract was mainly composed by polymeric flavanols (containing from two to seven units) and tannic acid (characterized by a mixture of glucose gallates containing from three to seven units of gallic acid). Concerning their antimycotic properties, P. maritima L. extract exhibited a broad activity towards yeast strains of the genera Candida, Cryptococcus, Filobasidiella, Issatchenkia, Saccharomyces: MICs from 200 to 4000 microg/ml (corresponding to 140-2800 microg/ml of active polyphenols) were determined. Conversely, no activity of tannic acid was observed over the same target microorganisms. Taken into consideration the above results of HPLC analysis and on the basis of the current literature, we may conclude that only 70.2% of polyphenols (recognized as condensed tannins) occurring in P. maritima L. extract can be apparently considered responsible for its antimycotic activity.

Antifungal Agents↗
PubMed2007

Hydrolyzable tannins with the hexahydroxydiphenoyl unit and the m-depsidic link: HPLC-DAD-MS identification and model synthesis.

This study was designed to develop efficient analytical tools for the difficult HPLC-DAD-MS identification of hydrolyzable tannins in natural tissue extracts. Throughout the study of the spectroscopic characteristics of properly synthesized stereodefined standards, it was observed that the UV-vis spectra of compounds with the m-depsidic link showed a characteristic shoulder at 300 nm, consistent with the simple glucogalloyl esters, whereas compounds with the hexahydroxydiphenoyl (HHDP) unit gave a diagnostic fragmentation pattern, caused by a spontaneous lactonization in the mass spectrometer. These observations were confirmed by HPLC-DAD-MS analyses of tannic acid and raspberry extracts, which are rich in hydrolyzable tannins with the m-depsidic link and the HHDP unit, respectively.

Chromatography, High Pressure Liquid↗