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PubMed2006

Effect of tea polyphenol on cytokine gene expression in rats with alcoholic liver disease.

BACKGROUND: Oxidative stress plays a pathogenetic role in initiation and progression of hepatic damage caused by alcohol. Recently, antioxidants have received considerable attention. Green tea polyphenols have both antioxidant and antiinflammatory properties. This study was designed to evaluate the effect of tea polyphenol (TP) on alcohol-induced liver injury in rats. METHODS: The rats were divided randomly into 3 groups: group A gastrically infused with alcohol for 12 weeks, group B fed with alcohol plus TP (250 mg/kg.d) simultaneously, and group C (control group) gastrically infused with normal saline. At the end of 12 weeks, the rats were sacrificed. The liver specimen of each rat was taken for histological examination. All data were statistically analyzed in quantum and semi-quantum. Gene expression of cytokines of each group was determined. RESULTS: At the end of 12 weeks, hepatic injury of different degrees developed in group A and group B compared to group C. The degree of hepatic injury was attenuated in group B, with slight steatosis, liver cellular swelling in small areas; less spot and focal necrosis, no bridging necrosis, less mega-bubble steatosis and less collagen deposition in contrast to group A. Gene expressions of IL-3, IL-4, IL-1R2, IL-6R, IL-7R2 were up-regulated in group B compared with group A, but those of IL-3Ra, IL-1R1 were down-regulated. Gene expressions of IL-13, IL-1R1, IL-7R2, EPO-R, LIFR were up-regulated in group A compared with group C, but those of IL-1R2, IL-5R2, CSF1, CD27, IL-6R were down-regulated. CONCLUSION: TP is able to attenuate alcoholic liver damage. Cytokine may contribute to alcoholic liver disease.

Animals↗
PubMed2006

[The effect of chewing gum containing tea polyphenol on salivary flow rate and pH].

PURPOSE: To investigate the change of saliva flow rate and pH after chewing tea polyphenol gum. METHODS: Saliva was collected before and after chewing tea polyphenol gum and the control gum. Both the salivary flow rate and pH value were measured and analyzed by one-way ANOVA and SNK. RESULTS: The chewing gum significantly increased the flow rate as well as pH value of the saliva. The flow rate of the tested and control gum reached peak in the first minute. They were 3.15+/-1.05 and 3.30+/-0.87 ml respectively. There was no significant difference between the chewing gums. CONCLUSION: Chewing gum can increase the secretion and elevate the pH value of the saliva which benefits oral health care.

Chewing Gum↗
PubMed1989

[The role of catecholaminergic synapses in the mechanisms of the formation of adaptation with the participation of polyphenol adaptogens].

The analysis of the role of catecholaminergic synapses in the process of adaptation showed that the main point of the influence of polyphenolic adaptogens was a catechol-O-methyltransferase. Inhibiting the latter, the polyphenolic adaptogens exert a correcting effect on catecholaminergic (mainly dopaminergic) synapses and prevent the transmitter from reduction in them.

Adaptation, Physiological↗
PubMed1993

The byssus of the zebra mussel, Dreissena polymorpha. II: Structure and polymorphism of byssal polyphenolic protein families.

The byssus of the zebra mussel Dreissena polymorpha is the key element of its adhesive strategy. It consists of a bundle of threads tipped by adhesive plaques and attached to the mussel at the base of its byssal-synthesizing organ, the foot. Two polyphenolic protein precursors of the byssus have been purified from the foot. These precursors, Dpfp-1 and Dpfp-2 (Dreissena polymorpha foot protein), with apparent M(r) values of 76 and 26 K, respectively, contain 3,4-dihydroxyphenylalanine (DOPA) integrated into their primary sequence, but differ from previously characterized polyphenolic proteins from marine mussels. The related quagga mussel (Dreissena spp.?) has homologous proteins with significantly different compositions. The zebra mussel DOPA proteins are tandemly repetitive with unique oligopeptide motif sequences, contain tryptophan, and are O-glycosylated primarily on threonine residues. Galactosamine was the only carbohydrate detected after hydrolysis. Dpfp-1 constitutes a polymorphic family of polypeptides with, unusually, an acidic range of pI values between 5.3 and 6.5. The detection of carbohydrate in the thread and in the juncture between thread and plaque suggests that these two proteins are localized in those regions where they may function as lacquers or structural elements.

Amino Acid Sequence↗
PubMed2000

Tandem mass spectrometry studies of green tea catechins. Identification of three minor components in the polyphenolic extract of green tea.

Liquid chromatography/electrospray ionization mass and tandem mass spectrometry (MS/MS) techniques were used to identify two minor components and one new compound in the polyphenolic extract of green tea (Camellia sinensis). Identification and structure assignments were based on previously reported sub-structural features in the MS/MS product, precursor and neutral loss scans of reference samples. The structures of two minor components, related to the known green tea components epicatechin gallate (ECG, 5) and epigallocatechin gallate (EGCG, 6), are formed by methylation at the 3"-O-position of the gallic acid moiety. The new compound contained a gallic acid ester group, but had only one phenolic group in either the A- or B-ring, relative to the structure of 5. High-resolution mass measurements supported the empirical formula assigned to the new compounds. An important fragmentation for defining the position of methylation of the ester function involves ionization of the phenolic group at the 4"-position of the gallic acid, followed by elimination of the ester function as a neutral with concomitant formation of the m/z 169 ion. If the 4"-position is blocked by methylation, the formation of m/z 169 incorporating the gallic acid group would be blocked. Thus, the presence of an ion representing the ester group indicates a free 4"-phenol and the absence of this ion would signify the 4"-position as a site of methylation. The operation of this mechanism should be general and useful in assigning the site of methylation of any polyphenolic ester group in natural products. A similar conclusion can be drawn concerning alkylation or esterification of the 4'-position of the catechins, i. e. blocking the 4'-phenol would prevent formation of the m/z 125 ion common to all of the catechin compounds thus far examined. Therefore, mass spectral data are of considerable importance in deducing the sites of alkylation or esterification in the structures of the components of green tea.

Catechin↗
PubMed2001

Identification of novel polyphenol oxidase inhibitors by enzymatic one-pot synthesis and deconvolution of combinatorial libraries.

The feasibility of enzymatic synthesis of combinatorial libraries using multifunctional starting materials [i.e., 2,4-dihydroxy-N-(2-hydroxyethyl)benzamide, 1; 4-hydroxyphenethyl alcohol, 2; 3,5-dihydroxybenzyl alcohol, 3; and 4-hydroxybenzyl alcohol, 4] with six vinyl esters, in a one-pot reaction, was investigated. Candida antarctica lipase was employed as a biocatalyst. The resulting 24-compound library contained all the expected species with no significant bias toward particular combinations of substrates. As expected, the library contained a substance(s) that showed significant inhibition of polyphenol oxidase, which was used as a model target. The deconvolution was accomplished via resynthesis of ten partial libraries, which were prepared with either an equimolar mixture of the four alcohols and a single vinyl ester, or a single alcohol and equimolar mixture of the activated esters. Analysis of the inhibition pattern observed with these partial libraries suggested that 4-hydroxybenzyl benzoate (4e) should be the most potent inhibitor. This conclusion was confirmed by the preparation and comparison of all 24 components of the initial library. Finally, it was shown that 4e was a competitive inhibitor of polyphenol oxidase, with a K(i) of 40 microM. This value compared favorably with a K(i) of 400 microM, which was determined for parent phenol 4.

Catalysis↗
PubMed2026

Dietary Polyphenol Acteoside-Related Molecular Signatures in Clear Cell Renal Cell Carcinoma: Multi-Omics Profiling and Functional Validation of IMPDH1.

Clear cell renal cell carcinoma (ccRCC) is characterized by substantial metabolic and molecular heterogeneity, but the disease-relevant programs associated with acteoside, a dietary polyphenol, remain poorly understood. We integrated predicted acteoside targets with bulk, single-cell, and spatial transcriptomic data from ccRCC and combined molecular subtyping with cross-cohort machine-learning analysis. Acteoside-related signatures were preferentially enriched in malignant compartments and increased with tumor grade and stage. Consensus clustering identified two molecular subtypes with distinct biological and clinical features. C1 was associated with immune activation, metabolic activity, and more favorable survival, whereas C2 showed greater genomic instability, reduced renal epithelial differentiation, and poorer outcomes. We further benchmarked multiple machine-learning strategies and established a 10-gene prognostic model that retained predictive performance across independent cohorts, with IMPDH1 emerging as the strongest risk-associated feature. Functional experiments confirmed the biological relevance of IMPDH1: its knockdown suppressed ccRCC cell proliferation, DNA synthesis, colony formation, and migration, whereas overexpression produced the opposite effects. Together, these findings indicate that acteoside-related molecular signatures capture clinically relevant heterogeneity in ccRCC and provide a framework for linking dietary-polyphenol-related molecular space with tumor biology. The identification and functional validation of IMPDH1 further highlight its potential importance in ccRCC progression.

IMPDH1↗
PubMed1997

4-Coumaroyl coenzyme A 3-hydroxylase activity from cell cultures of Lithospermum erythrorhizon and its relationship to polyphenol oxidase.

A 4-coumaroyl-CoA 3-hydroxylase activity was purified 4600-fold from cell cultures of Lithospermum erythrorhizon. The enzyme showed a molecular mass of 42,400 +/- 1700 Da in gel chromatography and required ascorbate, NADH, or NADPH as cofactors. 4-Coumaroyl-CoA, 4-coumarate, p-cresol, and several other phenolic substances, but not tyrosine, were accepted as substrates for the hydroxylation. Besides hydroxylase activity, the enzyme showed diphenol oxidase activity. Both activities were inhibited by diethyldithiocarbamate or beta-mercaptoethanol, although at different concentrations. The enzyme showed striking similarity to a 4-coumaroyl-glucose 3-hydroxylase from sweet potato (Ipomoe batatas) roots, which has reportedly been purified to homogeneity and identified as a specific enzyme of chlorogenic acid biosynthesis. Close examination and comparison to a commercially available polyphenol oxidase, however, suggest that the enzyme activities purified from both Lithospermum and sweet potato are polyphenol oxidases rather than specific enzymes of secondary metabolism.

Adenine Nucleotides↗
PubMed1993

New spectrophotometric assay for polyphenol oxidase activity.

We describe a convenient and sensitive assay of polyphenol oxidase (PPO, EC 1.14.18.1) consisting of spectrophotometry at 300 nm based on the stoichiometric reaction of cysteine with o-quinones produced during the enzymatic oxidation of phenols. The adduct formed exhibited spectral properties different from those of the parent phenol. PPO activities extracted from apple, pear, and mushroom were assayed. The assay cannot be used with hydroxycinnamoyl derivatives since the cysteinyl adduct compounds exhibited spectral properties similar to those of their parent phenolic substrates. However, the cysteine-coupled method presents several advantages over the measurement of oxygen uptake by polarography or the direct estimation of o-quinone by spectrophotometry. The duration of the linear period was increased, allowing a better estimation of its value. The zone of proportionality between rates and enzyme quantities was enlarged. The difference in molar extinction coefficients between adduct and phenol at 300 nm ranged between 2000 and 2800 M-1.cm-1, i.e., two times higher than those of the corresponding o-quinones. Therefore, this assay improves the sensitivity of polyphenol oxidase detection over that of the direct spectrophotometric assay of quinone formation.

Catechol Oxidase↗
PubMed1995

A continuous spectrophotometric method for determining the monophenolase and diphenolase activities of apple polyphenol oxidase.

A continuous spectrophotometric method for the determination of the monophenolase and diphenolase activities of apple polyphenol oxidase is described. The method is based on the coupling reaction between 3-methyl-2-benzothiazolinone hydrazone (MBTH) and the quinone product of the oxidation of p-hydroxyphenyl propionic acid and 3,4-dihydroxyphenyl propionic acid in the presence of polyphenol oxidase. The lambda(max) and molar absorptivity (epsilon) for the MBTH-quinone adduct have been calculated. The presence of MBTH in the reaction medium decreases the lag period during the expression of monophenolase activity. The high value of V(mas) suggests the existence of a high catalytic constant. This, together with the value of epsilon for the MBTH-quinone adduct, makes this method more sensitive than other continuous methods.

Catechol Oxidase↗
PubMed2000

An improved method for the determination of green and black tea polyphenols in biomatrices by high-performance liquid chromatography with coulometric array detection.

Tea polyphenols are strong antioxidants and are believed to have beneficial health effects. However, the blood and tissue levels of these compounds are not well characterized because of a lack of suitable analytical methods for the biological resolution of these compounds. Previously, we developed methods for the analysis of three green tea catechins. Now we report an improved method for the measurement of the levels of the different catechins and theaflavins in biological fluids and tissues. The method includes digestion of the plasma, urine, or tissue samples with beta-d-glucuronidase and sulfatase, followed by extraction with ethyl acetate and subsequent separation by reversed-phase high-performance liquid chromatography (HPLC). The polyphenols are identified on the basis of their retention times, spectral analysis, and electrochemical behavior across an array of electrodes. In a single HPLC run, it is possible to determine the major catechins and theaflavins as well as some of the catechin metabolites. The detection limits for catechins and theaflavins are from 5 to 10 ng/ml of saliva, plasma, or urine.

Adult↗
PubMed2002

The purification of polyphenol oxidase from tobacco.

A new polyphenol oxidase (PPO) named PPO II was purified from tobacco (Nicotiana tobacum) by using acetone powder, ammonium sulfate precipitation, and column chromatography on DEAE-Sephadex A-50, Sephadex G-75, and CM-Sephadex C-50. It has an active site of a pair of type 3 coppers bridged to phenolate oxygen, which represents a new catalytic mechanism for polyphenol oxidase. PAGE, SDS-PAGE, and matrix-assisted laser desorption/ionization-time of flight mass spectrometry of the purified enzyme demonstrated that the enzyme is a single band with a molecular mass 35,600 Da. Biochemical characteristics include the optimum pH at 6.0, optimum temperature at 40 degrees C, and K(m) of 1.2 mM for catechol as substrate (pH 6.5, 30 degrees C). Substrate specificity studies indicate that the enzyme is of the catechol oxidase family. PPO II inhibits cultures of Escherichia coli and it accumulates on the wounded sites of tobacco leaves indicating that it may act as a defense role in plant defense systems.

Catechol Oxidase↗
PubMed1996

(-)-Epigallocatechin gallate, a polyphenolic tea antioxidant, inhibits peroxynitrite-mediated formation of 8-oxodeoxyguanosine and 3-nitrotyrosine.

Reaction with peroxynitrite at pH 7.4 and 37 degrees C was found to increase the 8-oxodeoxyguanosine levels in calf thymus DNA 35- 38-fold. This oxidation of deoxyguanosine, as well as the peroxynitrite-mediated nitration of tyrosine to 3-nitrotyrosine, was significantly inhibited by ascorbic acid, glutathione and (-)-epigallocatechin gallate, a polyphenolic antioxidant present in tea. For 50% inhibition of the oxidation of deoxyguanosine to 8-oxodeoxyguanosine, 1.1, 7.6 or 0.25 mM ascorbate, glutathione or (-)-epigallocatechin gallate, respectively, was required. For 50% inhibition of tyrosine nitration, the respective concentrations were 1.4, 4.6 or 0.11 mM. Thus, (-)-epigallocatechin gallate is a significantly better inhibitor of both reactions than either ascorbate or glutathione. Reaction of (-)-epigallocatechin gallate with peroxynitrite alone resulted in the formation of a number of products. Ultraviolet spectra of two of these suggest that the tea polyphenol and/or its oxidation products are nitrated by peroxynitrite.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1994

Generation of Hydrogen Peroxide, Superoxide Anion and the Hydroxyl Free Radical from Polyphenols and Active Benzene Metabolites: Their Possible Role in Mutagenesis.

Benzene is strongly suspected of being an animal and human carcinogen, but the mechanisms by which it induces tumors of lymphoid and hematopoietic organs are unknown. Production of active oxygen species from benzene metabolites [hydroquinone (HQ), catechol and 1,2,4-benzenetriol (1,2,4-BT) and related polyphenols (resorcinol, pyrogallol and phloroglucinol)] are investigated. Pyrogallol and 1,2,4-BT can produce H(2)O(2), O(-)(2) and (.)OH simultaneously, and have powerful mutagenic potential. Resorcinol and phloroglucinol cannot produce all of the active oxygen species, and show no mutagenic effects. Catechol can produce H(2)O(2), but cannot produce O(-)(2) and (.)OH, and has no mutagenic activity. These data strongly support the hypothesis that benzene metabolites can cause mutagenicity via the generation of oxygen radicals. Although HQ produces H(2)O(2) only, and less than produced by pyrogallol and 1,2,4-BT, the mutagenicity of HQ is higher. The results indicate that HQ may act via another mechanism to cause mutagenicity. In the presence of trace metal ions, the reactivity of polyphenols is increased. The biological significance of these phenomena are investigated and discussed. Copyright 1994 S. Karger AG, Basel

Journal Article↗
PubMed1996

Decolorization of olive mill waste-waters by free and immobilized Phanerochaete chrysosporium cultures. Effect of the high-molecular-weight polyphenols.

This paper describes the decolorization and chemical oxygen demand (COD) removal of olive mill waste-waters (OMW) by Phanerochaete chrysosporium grown in agitated submerged cultures. When P. chrysosporium was cultivated in the form of pellet, no decolorization of crude OMW was observed. Decolorization occurred only after removing by ultrafiltration, the high-mol-wt (HM) polyphenolic fraction (> 60 kDa). The use of high lignin peroxidase (LiP) producing medium yielded the highest levels of OMW decolorization and COD removal. In this case, extensive depolymerization and subsequent accumulation of phenolics with intermediates molecular weight were observed. Furthermore, increasing the concentration of the HM fraction decreased the color and COD removals. The decolorizing activity was lost when the concentration of the HM fraction reached 25% (v/v). Consequently, LiP activity was found to be completely inhibited in the presence of HM fraction, but not with the low-mol-wt (LM) polyphenolic fraction (< 8 kDa). The use of P. chrysosporium immobilized on polyurethane foam resulted in efficient decolorization of crude OMW. Moreover, the addition of an induction medium was shown to perform several repeated batch cultures for OMW decolorization and COD removal.

Chrysosporium↗
PubMed2005

Prevention of bone loss by phloridzin, an apple polyphenol, in ovariectomized rats under inflammation conditions.

Aging and sex hormones related changes lead to inflammatory and oxidant conditions, which are involved in the pathogenesis of osteoporosis. Recent studies have suggested that polyphenols may exert a protective effect in such conditions. We assessed the effect of phloridzin (Phlo), a flavonoid exclusively found in apple, on bone metabolism in ovariectomized (OVX) or sham-operated (SH) rats with and without inflammation. Six-month-old Wistar rats were allocated to two equal groups that received either a control diet or a diet supplemented with 0.25% Phlo for 80 days. Three weeks before necropsy, inflammation was induced by subcutaneous injection of talc in 10 animals of each group. At necropsy, ovariectomy decreased both total (T-BMD) and metaphyseal (M-BMD) femoral bone mineral density (P < 0.01). Inflammation conditions, checked by an increase in the spleen weight and alpha1-acid glycoprotein concentration in OVX rats, exacerbated the decrease in T-BMD (g/cm2) (as well as M-BMD) observed in castrated animals (P < 0.05). Daily Phlo intake prevented ovariectomy-induced bone loss in conditions of inflammation as shown by T-BMD and M-BMD (P < 0.05). At the diaphyseal site, BMD was improved by Phlo in OVX rats with or without inflammation (P < 0.05). These results could be explained by changes in bone remodeling as the increased urinary deoxypyridinoline excretion in OVX and OVXinf animals was prevented by the polyphenol-rich diet (P < 0.001), while plasma osteocalcin concentration was similar in all experimental groups. In conclusion, Phlo consumption may provide protection against ovariectomy-induced osteopenia under inflammation conditions by improving inflammation markers and bone resorption.

Animals↗
PubMed2002

Laccases and other polyphenol oxidases in ecto- and ericoid mycorrhizal fungi.

Polyphenol oxidases are known to be produced by a range of ectomycorrhizal (ECM) and ericoid mycorrhizal fungi. These enzymes include laccase (EC 1.10.3.2), catechol oxidase (EC 1.10.3.1) and tyrosinase (EC 1.14.18.1), between which there exists considerable overlap in substrate affinities. In this review we consider the nature and function of these enzymes, along with the difficulties associated with assigning precise enzymatic descriptions. The evidence for production of laccase and other polyphenol oxidases by ECM and ericoid mycorrhizal fungi is critically assessed and their potential significance to the mycorrhizal symbioses discussed.

Ascomycota↗