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At least 325 records · Page 18Linked to original sources
PubMed1990

Woodfordin C, a macro-ring hydrolyzable tannin dimer with antitumor activity, and accompanying dimers from Woodfordia fruticosa flowers.

Three new dimeric hydrolyzable tannins, woodfordins A, B and C, along with seven known hydrolyzable tannins, including oenothein B, a dimer exhibiting marked host-mediated antitumor activity, were isolated from an Indonesian crude drug, Sidowayah [dried flowers of Woodfordia fruticosa (L.) Kurz (Lythraceae)]. The structures of the new tannins were elucidated based on chemical and spectral evidence. Woodfordin C, having a macro-ring structure, was also found to exhibit a significant antitumor activity.

Animals↗
PubMedDate not supplied

Inhibition of ultraviolet-B radiation induced ornithine decarboxylase activity and edema formation by hydrolyzable and condensed tannins in mouse skin in vivo.

Naturally occurring hydrolyzable (HT) and condensed (CT) tannins and their monomeric units were tested for their ability to inhibit the induction of epidermal ODC activity and the formation of skin edema by UVB, two responses that are linked to the hyperplastic and inflammatory components of skin tumor promotion by this agent. Hairless mice were irradiated with either single (200 mJ/cm2/sec) or multiple (150 mJ/cm2/sec) doses of UVB and epidermal ODC activity was assayed at different times following irradiation. The peak of ODC induction which is observed 30-40 hours after a single UVB irradiation increases by 2.5 fold and shifts to a much earlier time of 5 hours after two UVB treatments repeated at 24-hour intervals. Topical applications of the various plant tannins, before or after irradiation, were found to inhibit, in a dose-dependent manner, epidermal ODC activity induced by single and multiple UVB treatments. Furthermore, the various HT and CT samples resulted in significant protection against UVB radiation-caused cutaneous edema. In general, the polymeric tannins inhibited ODC induction and edema to a greater degree than equal doses of their monomeric units, gallic acid and catechin. These results, in conjunction with our prior publications, suggest that various HTs and CTs may be useful against the hyperplastic and inflammatory responses associated with the exposure of skin to the tumor-promoting effects of both physical and chemical environmental carcinogens.

Animals↗
PubMed1990

Prevention of hydrolysable tannin toxicity in goats fed Clidemia hirta by calcium hydroxide supplementation.

Although plants containing hydrolysable tannins can be hepatotoxic, such poisoning has not been reported in Indonesia despite the presence of these plants. In order to determine the hepatotoxic potential of Indonesian plants, goats were intoxicated experimentally with the Indonesian plant Climedia hirta (harendong), which contained 19% hydrolysable tannin. The prophylactic effect of Ca(OH)2 supplementation on the disease was also examined. Two groups of goats were fed for 28 days with grain-based pellets containing 50% harendong leaf or 50% harendong leaf + 8% Ca(OH)2. Two control groups were fed similar pellets containing 50% of the non-toxic elephant grass (Pennisetum purpureum) with and without 8% Ca(OH)2. Serum enzymes indicative of liver damage were monitored during the experiment and histopathological examination of selected tissues was done at the conclusion of the experiment. In goats given unsupplemented harendong pellets there was a significant increase in aspartate aminotransferase and glutamate dehydrogenase from 50.2 and 20.6 U l-1 to 219.6 and 63.3 U l-1, respectively. These changes were associated with moderate to severe nuclear plemorphism, vacuolation and megalocytosis of hepatocytes and deposits of brown pigment in the Kupffer cells. There was also nephrosis of the renal convoluted tubules and collecting ducts, abomasitis and enteritis. Biochemical and histological changes were reduced significantly in the harendong + Ca(OH)2 group and virtually absent from control groups. It is concluded that hydrolysable tannins in harendong leaf are hepato- and nephrotoxic and associated with gastroenteritis, but that poisoning may be ameliorated by Ca(OH)2 supplementation.

Abomasum↗
PubMed2004

Biosynthesis of tannase and gallic acid from tannin rich substrates by Rhizopus oryzae and Aspergillus foetidus.

Modified solid-state fermentation (MSSF) of tannin-rich substrates for production of tannase and gallic acid was carried out using two fungal cultures, Rhizopus oryzae (RO IIT RB-13, NRRL 21498) and Aspergillus foetidus (GMRB013 MTCC 3557). The tannin rich substrates included powdered fruits of Terminalia chebula and Caesalpinia digyna pod cover powder. The different environmental parameters for the maximum production of tannase and gallic acid were optimized through media engineering. The highest yield of tannase and gallic acid was obtained after 60 h in case of Rhizopus oryzae and after 72 h by Aspergillus foetidus with 3 ml of induced inoculum. The optimum initial pH of the fermentation was found to be 4.5 in case of Rhizopus oryzae and 5.0 for Aspergillus foetidus. MSSF was carried out at the optimum conditions of 30 degrees C and 80% relative humidity. Collectively, the data reveal the potential of the modified solid-state fermentation process for the production of tannase and gallic acid from tannin-rich substrates with R. oryzae and A. foetidus.

Aspergillus↗
PubMed2005

Solid sampling technique for direct detection of condensed tannins in bark by matrix-assisted laser desorption/ionization mass spectrometry.

A novel method for the direct analysis of condensed tannin components in bark was developed on the basis of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with a simple solid sampling technique. The MALDI mass spectra obtained from the wood (bark) powder sample clearly showed a series of peaks corresponding to the sodium ion adducts of condensed tannin oligomers up to around m/z 3000. The results indicate that the condensed tannins in the bark sample used in this work mostly consist of combinations of flavan-3-ol units such as profisetinidin (PF), prorobinetinidin (PR) and prodelphinidin (PD), at least up to 10-mers (m/z approximately 3000).

Acacia↗
PubMed2000

Toxicity of vegetable tannins on crustacea associated with alpine mosquito breeding sites.

The impact of tannins from the environmental vegetation naturally polluting Alpine mosquito breeding sites was experimentally investigated by studying the toxicity of tannic acid, a natural hydrolyzable tannin, on the nontarget crustacean fauna associated with culicine populations. Bioassays indicate that exposure to tannic acid at concentrations from 0.06 to 2.0 mM is more deleterious to Chydorus sphaericus, Diaptomus castor, and Eucypris fuscata, than to Daphnia pulex, Acanthocyclops robustus, and Eucypris virens. Histopathological investigations after treatment with tannic acid at concentrations from 0.125 to 0.500 mM reveal sequential degenerative patterns of the midgut epithelium depending on the taxon, duration of the treatment, and concentrations assayed. These differential toxic effects on Crustacea are compared with those previously observed in larval Diptera, in order to evaluate the plant tannins as potentially useful products in integrated mosquito management programs.

Animals↗
PubMed1992

Antinutritional effects of condensed and hydrolyzable tannins.

Despite major structural differences, hydrolyzable and condensed tannins often produce similar antinutritional effects. The most common effects are diminished weight gains and lowered efficiency of nutrient utilization. The major biochemical basis for these effects appears not to be inhibition of dietary protein digestion but rather a systemic inhibition of the metabolism of digested and absorbed nutrients, particularly protein. In the case of condensed tannins, this inhibition is probably not due to polymeric tannin molecules, which are not absorbed from the digestive tract, but to associated lower MW polyphenols, which are readily absorbed.

Animals↗
PubMed1992

Prosopis cineraria leaf tannins: their inhibitory effect upon ruminal cellulase and the recovery of inhibition by polyethylene glycol-4000.

The condensed tannins from the Prosopis cineraria leaves were purified and fractionated in two groups (Kav 0.018 and 0.74) on a column of Sephadex LH-20 (2.5 x 27 cm) using 70 percent aqueous acetone as the eluent. The Kav for catechin was 0.946. Upon acid hydrolysis, both the condensed tannin fractions yielded three pigments including cyanidin-chloride, which was separated by column chromatography using polyvinylpyrrolidone absorbent and was identified by paper chromatography (Rf Forestal 0.476) and absorption maxima (lambda max 535 nm) in 1 percent HCl in methanol. The condensed tannin fraction Kav 0.74 at 0.01 percent and 0.02 percent in incubations with butanol-acetone powder of rumen liquor, inhibited cellulase activity by 65.9 +/- 2.1 and 78.99 +/- 4.5 percent, respectively. Inclusion of 0.5 percent of polyethylene glycol -4000 in the incubation mixture, reduced the inhibition to 41 and 46 percent, respectively.

Animals↗
PubMed1989

Tannin mediated alveolar macrophage protein phosphorylation.

Experiments were designed to determine if cotton bract tannin, a component of cotton mill dust, would promote the phosphorylation of alveolar macrophage proteins in doses potentially achievable in vivo. Rabbit alveolar macrophages were loaded with 32PO4 and challenged with various doses of tannin for time periods ranging from two seconds to 120 minutes. Changes in protein phosphorylation began after two seconds and were maximal at five to fifteen minutes. Dose response studies using an exposure time of one hour showed phosphorylation changes began at 1 micrograms/mL and were maximal at 10 to 30 micrograms/mL. Phosphorylation changes were similar to but not identical to those induced by the protein kinase C activator, phorbol myristate acetate (PMA). Calcium ionophore, A-23187 had no clear effect either alone or in conjunction with PMA. These results indicate that cotton bract tannin is able to rapidly promote protein phosphorylation of alveolar macrophages at doses potentially achievable in vivo. Other mechanisms in addition to those of protein kinase C appear to be involved in this protein phosphorylation process.

Animals↗
PubMed1993

Effect of reconstitution and Na2Co3 on tannin content and in vitro protein digestibility of faba bean cultivars.

Two faba bean cultivars (317/99/81 and Giza/402) obtained from Shambat Research Station in Northern Sudan, were used for this study. Investigation showed that the tannin contents of untreated seeds were 0.077% and 0.067% for cultivars 317/99/81 and Giza/402. In vitro protein digestibility values were 80.68% and 81.48% for the two cultivars, respectively. The extractable tannin content of the faba bean cultivars was markedly reduced by imbibing water or Na2CO3 solution into whole seeds and incubating them at 30 degrees C for 1, 3, 6, 12 or 24 hours, or at 100 degrees C for 5, 10 or 20 minutes. The extent of reduction depended on time, temperature, and Na2CO3 concentration; the percent tannin extracted and percent in vitro protein digestibility increased with time or Na2CO3 concentration, while application of high temperature reduced the time.

Carbonates↗
PubMed1994

Tannins in utilization of sorghum grains in Burkina Faso.

The study of thirty sorghum varieties used for food in Burkina Faso showed a relationship between tannin level and utilization of sorghum grain. High tannin level varieties (more than 0.2%) are generally used for local alcoholic drink, instead low tannin level varieties (under 0.2%) are used for cooking and for non fermented drinks.

Alcoholic Beverages↗
PubMed2006

A modified method for determining tannin-protein precipitation capacity using accelerated solvent extraction (ASE) and microplate gel filtration.

The protein precipitation assay used by Robbins et al., (1987) Ecology 68:98-107 has been shown to predict successfully the reduction in protein availability to some ruminants due to tannins. The procedure, however, is expensive and laborious, which limits its utility, especially for quantitative ecological or nutritional applications where large numbers of assays may be required. We have modified the method to decrease its cost and increase laboratory efficiency by: (1) automating the extraction by using Accelerated Solvent Extraction (ASE); and (2) by scaling and automating the precipitation reaction, chromatography, and spectrometry with microplate gel filtration and an automated UV-VIS microplate spectrometer. ASE extraction is shown to be as effective at extracting tannins as the hot methanol technique. Additionally, the microplate assay is sensitive and precise. We show that the results from the new technique correspond in a nearly 1:1 relationship to the results of the previous technique. Hence, this method could reliably replace the older method with no loss in relevance to herbivore protein digestion. Moreover, the ASE extraction technique should be applicable to other tannin-protein precipitation assays and possibly other phenolic assays.

Chemical Precipitation↗
PubMed2006

Fate of tannins in Corsican pine litter.

Tannins are ubiquitous in higher plants and also in litter and soils where they affect many biogeochemical processes. Despite this well-recognized role, their fate in litter and mineral soils is hardly known, as often only trace amounts, if any, are measured. In this study, we conducted an incubation experiment with Corsican pine litter to which known amounts of tannic acid (TA) or condensed tannins (CTs) from Corsican pine were added. Using Folin-Ciocalteu as a measure for total phenolics and HCl-butanol as an assay specific for CTs, acetone/water extractable phenolics and tannins decreased with time towards very low levels. Application of thermally assisted hydrolysis and methylation to litter before and after acetone/water extraction revealed that TA concentration decreased. By contrast, CTs remained to a great extent in the litter and could not be extracted suggesting that they were tightly bound.

France↗
PubMed2005

Tannins, trypsin inhibitors and lectin cytotoxicity in tepary (Phaseolus acutifolius) and common (Phaseolus vulgaris) beans.

This study compared the levels of antinutritional components and cytotoxic effect of extracts, from tepary (Phaseolus acutifolius) and common (Phaseolus vulgaris) beans. Antinutritional factors were evaluated by determining their effect on the viability of epithelial cells isolated from rat small intestine. The protein and carbohydrates content were similar in all the genotypes studied (20 and 60%, respectively). Common beans presented higher content of trypsin inhibitors, tannins and lectins than tepary beans. There was not a significant correlation between tannins and cooking time. However, water absorption and cooking time correlated significantly (p < 0.05). Considerable variation was observed in lectin activity (1302-18161 Ul/mg) of extracts from different beans. Tannins, lectins, trypsin inhibitors and fat content differed between bean varieties whereas protein content was similar. The percent cellularity on rat epithelial cells was significantly different among protein extracts from different bean cultivars and ranged between 53.5% and 87.4% (p < 0.05). These results suggest that the incorporation of tepary beans in the diet would not alter the current nutritional contribution of common beans or introduce adverse toxic effects. The agronomic characteristics of tepary beans make them attractive for cultivation. However, the harder to cook phenomenon may be a limiting factor that needs further consideration.

Animals↗
PubMed1995

Inhibition of constitutive endothelial NO-synthase activity by tannin and quercetin.

The effect of natural polyphenols on three isoforms of NO-synthase was investigated. Among the compounds tested, tannin was the most potent, inhibiting endothelial constitutive NO synthase (eNOS) with an IC50 of 2.2 microM. Other NOS isoforms (i.e. neuronal constitutive NOS and smooth muscle inducible NOS) were also inhibited but at much higher concentrations (selectivity ratio of approx. 20-30). Quercetin was also an effective but less potent inhibitor of eNOS (IC50 = 220 microM). The kinetics of tannin inhibition were investigated to gather information on the mechanism of action. Tannin did not interfere with the interaction of the enzyme with the co-substrates L-arginine and NADPH nor with the cofactor tetrahydrobiopterin. The inhibition level was also independent of free Ca2+ concentration as well as of the presence of high exogenous calmodulin concentrations.

Amino Acid Oxidoreductases↗
PubMedDate not supplied

Inhibition of herpes simplex virus infection by tannins and related compounds.

Several chemically defined plant extracts were investigated for their antiviral action on herpes simplex virus (HSV-1, HSV-2)-infected African green monkey kidney cells and human adenocarcinoma cells, using a plaque formation assay. Among them, the monomeric hydrolyzable tannins, oligomeric ellagitannins and condensed tannins, having galloyl groups or hexahydroxydiphenoyl groups, had the most potent anti-HSV activity. Their 50% effective doses (0.03-0.1 microgram/ml) were by two-three orders of magnitude lower than their 50% cytotoxic doses (greater than 10 micrograms/ml). On the other hand, gallic acid, neutral polysaccharides, chemically modified (N,N-dimethylaminoethyl-, carboxymethyl-, and sulfated-) glucans, sialic acid-rich glycoproteins, and uronic acid-rich pine cone polysaccharide showed little or no activity. Using radiolabeled virus particles, we demonstrated that the anti-HSV effect of the tannins is due to inhibition of virus adsorption to the cells.

Adsorption↗
PubMed2004

Formation of tannin-albumin nano-particles at neutral pH as measured by light scattering techniques.

Aggregation phenomena of tannin with bovine serum albumin were investigated by light scattering techniques including photon correlation spectroscopy and Rayleigh scattering. Tannin and albumin formed particles with diameters less than 1 microm at neutral pH. As revealed by this study, light scattering methods are useful in investigating aggregation phenomena of biomolecules and in directly quantifying tannin content.

Animals↗
PubMed2006

Gallic acid and tannase accumulation during fungal solid state culture of a tannin-rich desert plant (Larrea tridentata Cov.).

Larrea tridentata (Sesse & Mocino ex DC.) Coville, also known as Larrea, gobernadora, chaparral, or creosote bush, is a shrubby plant which dominates some areas of the desert southwest in the United States and Northern Mexico and its use has not been exploited and standardized. In this study, gobernadora was studied to evaluate its potential use for support of solid state culture. Influence of two minimal media added with gobernadora powder as the sole carbon source and inducer of tannin-degrading enzymes was evaluated. Cultures were initially 70% moisture, had a pH of 5.5 and were inoculated with Aspergillus niger Aa-20 at 2 x 10(7) spores per gram of media. Analysis of pH, moisture, tannin uptake, gallic acid accumulation and tannase production were evaluated. Results indicated a high content of condensed (39.4%dm) and hydrolysable (22.8%dm) tannins. Invasion capacity of fungal growth was of 0.15 mmh(-1). Tannase production reached values of 1040 Ul(-1) at 43 h of culture. During the first 48 h of culture, the concentration of gallic acid accumulation was 0.33 gl(-1). Gobernadora is a potential source of gallic acid and tannase production by solid state culture; however, further optimization of the process is needed.

Aspergillus niger↗