Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “TANNINS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,459 records · Page 81Linked to original sources
PubMed1996

Determination of oenothein B as the active 5-alpha-reductase-inhibiting principle of the folk medicine Epilobium parviflorum.

Several extracts from Epilobium parviflorum, a plant used in Central Europe for the treatment of prostate disorders, were evaluated in a biochemical assay with 5-alpha-reductase. The aqueous extract displaying inhibition of the enzyme was analyzed, the fraction responsible for this activity was purified, and the active compound identified as a macrocyclic tannin, oenothein B (1).

5-alpha Reductase Inhibitors↗
PubMed1993

Inhibition of DNA topoisomerases by sanguiin H-6, a cytotoxic dimeric ellagitannin from Sanguisorba officinalis.

Many tannins were previously identified as candidate topoisomerase poisons. Here we report further studies on sanguiin H-6, a dimeric ellagitannin isolated from Sanguisorba officinalis as an inhibitor of DNA topoisomerases. Catalytic strand-passing activities of topoisomerases I and II were inhibited in vitro with IC50 values of 1 microM and 0.01 microM, respectively. This inhibition was not associated with stabilization of covalent enzyme-DNA complexes but rather by a mechanism preventing formation of such covalent intermediates, as measured by interference with drug-induced cleavage in vitro. The IC50 values for topoisomerase I-DNA complexes induced by camptothecin and with topoisomerase II-DNA complexes induced by VP-16 were 0.02 microM and 0.16 microM, respectively. Pre-incubation studies followed by drug-dilution revealed that the in vitro inhibitory effects of sanguiin H-6 were irreversible, and for topoisomerase I, the test compound prevented enzyme-DNA interaction as seen by shifts in mobility on agarose gels. By measuring interference with drug-induced protein-linked DNA breaks in isolated HeLa nuclei, inhibition of topoisomerases I and II on a natural chromatin template was demonstrated with IC50 values of 5 microM and > 10 microM, respectively. Sanguiin H-6 inhibited HeLa cell growth with an ED50 of 12 microM and also interfered in a dose-dependent fashion with intracellular topoisomerase activities but with lower potencies than those observed using subcellular assay systems. Based on these studies, sanguiin H-6 could be broadly classified as a type of poison which does not stimulate the formation of cleavable-complexes, with intracellular activity but without any marked selectivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Catalysis↗
PubMed1977

Chemical interactions between thiamin and tannic acid. I. Kinetics, oxygen dependence and inhibition by ascorbic acid.

Consumption of food high in tannins can cause thiamin deficiency. The interactions between tannic acid and thiamin were studied by allowing them to react at pH 7.5, 60 C, and determining free remaining thiamin by the thiochrome method and by recording changes in ultraviolet absorption profiles at intervals. The reaction was biphasic, having a rapid initial phase which was oxygen-independent, followed by a slower phase which was oxygen concentration-dependent. Ascorbic acid completely inhibited the reaction if present at the beginning of the reaction and could partially reverse the reaction if added during the first 30 min.

Antimetabolites↗
PubMed1998

The influence of acid on astringency of alum and phenolic compounds.

Astringency of aqueous solutions of phenolic compounds (grape seed tannins, tannic acid, catechin and gallic acid) increased upon addition of citric acid, whereas the astringency of alum was reduced. Astringency of alum was decreased equivalently by addition of equi-sour levels of lactic acid, citric acid or hydrochloric acid. The difference between alum and the phenolic compounds is speculated to result from chemical modifications affecting binding of the astringents with oral proteins rather than cognitive differences. Chelation of the aluminum ion in alum by acids reduces its availability for interacting with salivary proteins or epithelial proteins. In contrast, the increased astringency produced upon acidification of phenolic compounds is speculated to result from the pH driven increase in the affinity of the phenols for binding with proteins. These results suggest that alum cannot be used interchangeably with phenolic astringents in psychophysical studies.

Adult↗
PubMed2001

Biochemical characterization of galloyl pedunculagin (ellagitannin) as a selective inhibitor of the beta-regulatory subunit of A-kinase in vitro.

The inhibitory effects of galloyl pedunculagin (GP) and eugeniin on the phosphorylation of histone H2B by cAMP-dependent protein kinase (A-kinase) and autophosphorylation of its beta-regulatory subunit (A-kinase beta) were examined in vitro. It was found that (i) GP (ID(50) = approx. 50 nM) effectively inhibits the activity of A-kinase (heterodimer), but high doses are required to inhibit the activities of the alpha-catalytic subunit (ID(50) = approx. 0.25 microM) and casein kinase II (CK-II, ID(50) = approx. 0.6 microM); (ii) GP inhibits the autophosphorylation of A-kinase beta in a dose-dependent manner with an ID(50) of approx. 6.6 nM, which is about 30-fold lower than that observed with CK-II beta; and (iii) GP reduces the suppressive effect of the beta-subunit on the activity of the alpha-subunit. In addition, purified bovine heart A-kinase precipitates when incubated with excess GP at pH 5.0. A similar precipitation of A-kinase was observed with eugeniin. These results show that the direct binding of GP to the beta-subunit prevents the physiological interaction between the beta- and alpha-subunits of A-kinase in vitro. This conclusion is presumably consistent with the binding affinity of proline-rich proteins with tannins, since A-kinase beta contains a proline-rich domain that interacts with GP or eugeniin. Therefore, GP will serve as a powerful inhibitor for in vitro and in vivo cellular studies of A-kinase beta-mediated signal transduction.

Animals↗
PubMed1994

Antihypertensive action of geraniin in rats.

The effects of geraniin, one of the ellagitannins purified from the leaves of Sapium sebiferum, on blood pressure were investigated in the spontaneously hypertensive rat (SHR). A single intravenous bolus injection of geraniin into anaesthetized SHRs lowered the arterial mean blood pressure in a dose-dependent manner without affecting the heart rate. A similar action was also observed in the normotensive (WKY) rat that received this compound at a higher dose. Geraniin did not modify the baroflex sensitivity in the phenylephrine-challenged SHR. This tannin reduced the plasma noradrenaline in a dose-dependent fashion which was not influenced by adrenalectomy. Failure of the antagonists, idazoxan and yohimbine for alpha 2-adrenoceptors as well as haloperidol and domperidone for dopamine receptors, to reverse the antihypertensive actions of geraniin ruled out the possible mediation of these receptors. Moreover, geraniin attenuated the pressor responses to exogenous noradrenaline and Bay K 8644 to a similar degree, indicating the direct effect of this compound on vascular activity in rats. These results suggest that geraniin possesses the ability to lower systemic blood pressure through the reduction of noradrenaline release or by direct vasorelaxation.

Adrenalectomy↗
PubMed1998

Antioxidant and hepatoprotective activity of punicalagin and punicalin on carbon tetrachloride-induced liver damage in rats.

Punicalagin and punicalin, isolated from the leaves of Terminalia catappa L., are used to treat dermatitis and hepatitis. Both compounds have strong antioxidative activity. The antihepatotoxic activity of punicalagin and punicalin on carbon tetrachloride (CCl4)-induced toxicity in the rat liver was evaluated. Levels of serum glutamate-oxalate-transaminase and glutamate-pyruvate-trans-aminase were increased by administration of CCl4 and reduced by drug treatment. Histological changes around the liver central vein and oxidation damage induced by CCl4 also benefited from drug treatment. The results show that both punicalagin and punicalin have anti-hepatotoxic activity but that the larger dose of punicalin induced liver damage. Thus even if tannins have strong antioxidant activity at very small doses, treatment with a larger dose will induce cell damage.

Alanine Transaminase↗
PubMed1991

Effects of geraniin on morphology and function of macrophages.

The effects of geraniin, a tannin, isolated from Geranium thunbergii Sieb. et Zucc. on the morphology and function of macrophages were studied. Geraniin caused a marked retardation of the recovery from fully spread surface membrane and a highly reorganized cytoskeleton of macrophages, whereas endocytotic activity, phagocytosis and pinocytosis in the cells were significantly inhibited.

Actin Cytoskeleton↗
PubMed2000

Inhibitory effect of sanguiin H-11 on chemotaxis of neutrophil.

Neutrophil is accumulated by chemoattractants at inflammatory sites. In order to find a new substance to regulate the chemotaxis of neutrophil, we examined the effects of purified tannins and related compounds (33 species). Among those studied, sanguiin H-11, purified from the plant Sanguisorba officinalis, was the most potent inhibitor of rat cytokine induced neutrophil chemoattractant-1 (CINC-1, a counterpart of human GRO (melanoma growth-stimulating activity)) dependent chemotaxis in rat neutrophils. Sanguiin H-11 inhibited platelet-activating factor- and N-formylmethionyl-leucyl-phenylalanine-dependent chemotaxis of neutrophil in addition to CINC-1-dependent reactions. Sanguiin H-11 also inhibited chemokinesis of neutrophil, but did not drastically affect the increase of intracellular free [Ca2+] level or degranulation monitored by the secretion of elastase, following chemoattractant stimulation. These results indicated that sanguiin H-11 is a potent inhibitor of chemoattractant-dependent and independent neutrophil movement.

Animals↗
PubMed2000

A study on the nitric oxide production-suppressing activity of sanguisorbae radix components.

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.

Animals↗
PubMed1989

Camelliin B and nobotanin I, macrocyclic ellagitannin dimers and related dimers, and their antitumor activity.

Camelliin B and nobotanin I, dimeric hydrolyzable tannins of a new class having macrocyclic structures, were isolated from Camellia japonica and Heterocentron roseum, respectively. Nobotanin G and H of the structures related to nobotanin I, were also obtained from H. roseum. Camelliin B and also woodfordin C, a macrocyclic dimer from Woodfordia fruticosa, exhibited marked host-mediated antitumor activities.

Animals↗
PubMed1990

Constituents of the leaves of Woodfordia fruticosa Kurz. I. Isolation, structure, and proton and carbon-13 nuclear magnetic resonance signal assignments of woodfruticosin (woodfordin C), an inhibitor of deoxyribonucleic acid topoisomerase II.

Woodfruticosin (woodfordin C), a new cyclic dimeric hydrolyzable tannin having an inhibitory activity toward deoxyribonucleic acid (DNA) topoisomerase II, has been isolated from the leaves of Woodfordia fruticosa Kurz (Lythraceae) along with three known flavonol glycosides and three known flavonol glycoside gallates. The structure of wood fruticosin (woodfordin C) was determined by the use of two-dimensional nuclear magnetic resonance (2-D NMR) spectroscopy including heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond connectivity (HMBC) techniques. Detailed analyses of the proton and carbon-13 NMR (1H- and 13C-NMR) spectra of six known flavonoids were performed.

Carbon Isotopes↗
PubMed2000

Effects of pH and light on the storage stability of the purple pigment, hordeumin, from uncooked barley bran fermented broth.

The pigment retention rate of hordeumin was higher than that of two standard anthocyanidins, cyanidin and delphinidin, when hordeumin and anthocyanidins were dissolved in Walpole buffer (pH 1.0) and stored. Moreover, when pigment solutions were stored at 15 degrees C under light irradiation, the pigment retention rate of the hordeumin solution became higher than those of standard anthocyanidins (2 to 10 times) as the storage period increased. Comparing various pH buffers (MacIlvaine buffer, pH 2.2 to 7.0), the pigment retention rate of hordeumin at pH 5.0 was highest. Furthermore, the half-life of hordeumin at pH 5.0 was increased from 9 days to 17.5 days when nitrogen gas was bubbled into the hordeumin solution. We considered that the storage stability of hordeumin is higher than standard anthocyanidins because hordeumin is a complex with anthocyanin, tannin, and protein.

Anthocyanins↗
PubMed2000

Antimutagenicity of the purple pigment, hordeumin, from uncooked barley bran-fermented broth.

The novel purple pigment hordeumin, an anthocyanin-tannin pigment, was produced from barley bran-fermented broth. The mutagenicity or antimutagenicity of hordeumin was investigated according to the Ames method, an indication of the safety of food, using Salmonella typhimurium TA98. Despite the presence of S-9 mix, hordeumin was not mutagenic. On the other hand, hordeumin effectively decreased a reverse mutation from Trp-P-1, Trp-P-2, IQ, and B[a]P. Furthermore, hordeumin also decreased the reverse mutation from dimethyl sulfoxide extracts of grilled beef.

Anthocyanins↗
PubMed1986

Methanol extract of grain dust shows complement fixing activity and other characteristics similar to tannic acid.

We have found several similarities between tannic acid and grain dust extract prepared with methanol. Both formed a precipitate with IgG, and these interactions were inhibited by albumin. In addition, both preparations fixed complement; this activity was heat stable and was removed by prior adsorption of the preparations with hide powder. Adsorption with polyvinyl polypyrrolidone reduced the complement-fixing activity of tannic acid but not that of the methanol grain dust extract. The similarities between tannic acid and the methanol grain dust extract are consistent with the presence of a tannin or tanninlike material in grain dust.

Animals↗
PubMedDate not supplied

Cytotoxic effects of cuphiin D1 on the growth of human cervical carcinoma and normal cells.

Cuphiin D1 (CD1), macrocyclic hydrolyzable tannin isolated from Cuphea hyssopifolia, has been shown to exert an antitumor effect both in vitro and in vivo. Furthermore, CD1 significantly inhibited the growth of the human cervical carcinoma, i.e. HeLa, cells and showed less cytotoxicity to normal primary-cultured cervical fibroblasts. In this study, we explored the cytotoxic mechanism of CD1 on HeLa cells. The cytotoxic effects of CD1 showed dose-dependency at 3.15-100 micrograms/ml on HeLa for 12, 24, 48 and 72 hours and with an IC50 value at 14.2 micrograms/ml for 48 hours. However, the IC50 value of CD1 in primary-cultured normal cervical fibroblasts was 74.5 micrograms/ml. Therefore, the selectivity shown by CD1 is ascribed to differences in growth speeds between normal and tumor cells. HeLa cells treated with 50 micrograms/ml CD1 for 24 hours exhibited chromatin condensation, indicating the occurrence of apoptosis. Flow cytometric analysis demonstrated the presence of apoptotic cells with low DNA content among HeLa cells. CD1 also caused DNA fragmentation and inhibited Bcl-2, pro-caspase 3, and inactived PARP expression in HeLa cells. These results suggest that the inhibition of Bcl-2 expression in HeLa cells might account for the mechanism of CD1-induced apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMedDate not supplied

In vitro immunomodulatory effects of cuphiin D1 on human mononuclear cells.

Cuphiin D1 (CD1), a macrocyclic hydrolyzable tannin isolated from Cuphea hyssopifolia, has been shown to exert antitumor activity both in vitro and in vivo. Moreover, the antitumor effects of CD1 are not only related to its cytotoxicity to carcinoma cell lines, but also depend on host-mediated mechanisms. In the present study, CD1 was investigated for its effects on the proliferation and cytokine secretion of human peripheral blood mononuclear cells (PBMCs). At concentrations of from 6.25 to 50 micrograms/ml, it enhanced the 3H-thymidine incorporation of concanavalin A (Con A)-stimulated PBMCs in a dose-dependent manner. Excretion of IL-1 beta, IL-2 and TNF-alpha by CD1-stimulated PBMCs was markedly increased in a dose-dependent manner. The results show that CD1 could stimulate PBMCs release of IL-1 beta, IL-2 and TNF-alpha and then activate T cells. Therefore, CD1-activated T cells via IL-1 beta in vitro might account for the host-mediated CD1 mechanism of action.

Adjuvants, Immunologic↗
PubMed2004

Effects of chebulinic acid on differentiation of human leukemia K562 cells.

AIM: To study effects of chebulinic acid on erythroid and megakaryocytic differentiation in K562 cells. METHODS: The benzidine staining method was used to evaluate hemoglobin synthesis; the expression of erythroid specific glycophorin A (GPA) protein and megakaryocytic surface marker CD61 was determined by flow cytometry using fluorescence labeled antibodies; erythroid and megakaryocytic mRNA expression was analyzed by RT-PCR. RESULTS: During erythroid differentiation induced by butyric acid (BA) or hemin, chebulinic acid not only inhibited the hemoglobin synthesis of BA- and hemin-treated K562 cells in concentration-dependent manner with IC50 of 4 micromol/L and 40 micromol/L respectively, but also inhibited another erythroid differentiation marker acetylcholinesterase at the concentration of 50 micromol/L in the cells either treated or untreated with each erythroid differentiation inducers, whereas chebulinic acid 50 micromol/L did not change GPA protein expression in these cells significantly. When K562 cells were treated with TPA 50 microg/L for 72 h to induce megakaryocytic differentiation, the presence of chebulinic acid 50 micromol/L slightly provoked the decrease of GPA protein expression induced by TPA. Chebulinic acid did not change the TPA-induced CD61 expression at the same concentration. Chebulinic acid also reduced the mRNA levels of erythroid relative genes including gamma-globin, PBGD, NF-E2, and GATA-1 genes in K562 cells either treated or untreated with BA, whereas chebulinic acid upregulated the mRNA levels of GATA-2 transcription factor in these cells. CONCLUSION: Chebulinic acid had inhibitory effect on erythroid differentiation likely through changing transcriptional activation of differentiation relative genes, which suggests that chebulinic acid or other tannins might influence the efficiency of some anti-tumor drugs-induced differentiation or the hematopoiesis processes.

Acetylcholinesterase↗