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PubMed2002

Antioxidant activity of dodecyl gallate.

Dodecyl (C12) gallate exhibits both potent chain-breaking and preventive antioxidant activity. The pyrogallol moiety is responsible for both activities. Dodecyl (lauryl) gallate prevents generation of superoxide radicals by xanthine oxidase, and this activity comes from its ability to inhibit the enzyme. The inhibition kinetics analyzed by Lineweaver-Burk plots found that dodecylgallate is a noncompetitive inhibitor for the generation of superoxide anion. Dodecyl gallate also inhibits formation of uric acid. The inhibition kinetics analyzed by Lineweaver-Burk plots found that dodecyl gallate is a competitive inhibitor for this oxidation. Mitochondrial lipid peroxidation induced by Fe(III)-adenosine 5'-diphosphate/reduced nicotinamide adenine dinucleotide was inhibited by dodecyl gallate while its parent compound, gallic acid, did not show this inhibitory activity. Dodecyl gallate protected mitochondrial functions and human red blood cells against oxidative stresses, but gallic acid showed little effect. The hydrophobic dodecyl group is largely associated with the preventive antioxidative activity.

Animals↗
PubMed2006

[Study on influence of processing methods on chemical constituents in Radix Paeoniae Alba].

OBJECTIVE: The influence of processing methods on chemical constituents in Radix Paeoniae Alba was observed. METHOD: A HPLC method was used for analyzing the changes of eight major constituents, namely gallic acid, paeoniflorin sulfonate, catechin, paeoniflorin sulfonate, albiflorin, paeoniflorin, benzoic acid, pentagalloylglucose and benzoylpaeoniflorin, with the three processing procedures of decorticating, boiling and fumigating by burning of sulphur. Analysis was performed using a Zorbax SB-C18 column (4.6 mm x 250 mm, 5 microm) with the mixture of acetonitrile (A) and 0.015% phosphoric acid solution as mobile phase in gradient mode. The detection wavelength was set at 230 nm and the column temperature was at 30 degrees C. RESULT: Except for gallic acid and pentagalloylglucose, the other constituents decreased during procedure of decorticating and boiling. Fumigating by burning of sulphur would produce a new compound, paeoniflorin sulfonate, which was a byproduct from the reaction of paeoniflorin with SO2. CONCLUSION: The significant changes were produced in chemical constituents of Radix Paeoniae Alba during three processing procedures. Therefore, the processing of Radix Paeoniae Alba should be strictly controlled and standardized.

Benzoates↗
PubMed2002

Novel fluorometric assay for hydroxyl radical prevention capacity using fluorescein as the probe.

A novel fluorometric method has been developed to evaluate hydroxyl radical prevention capacity using fluorescein (FL) as the probe. The hydroxyl radical is generated by a Co(II)-mediated Fenton-like reaction, and the hydroxyl radical formation under the experimental condition is indirectly confirmed by the hydroxylation of p-hydroxybenzoic acid. The fluorescence decay curve of FL is monitored in the absence or presence of antioxidant, the area under the fluorescence decay curve (AUC) is integrated, and the net AUC, which is an index of the hydroxyl radical prevention capacity, is calculated by subtracting the AUC of the blank from that of the antioxidant. Gallic acid is chosen as a reference standard, and the activity of sample is expressed as gallic acid equivalents. The method is rigorously validated through linearity, precision, accuracy, and ruggedness. A wide range of phenolic antioxidants is analyzed, and the hydroxyl radical prevention capacity is mainly due to the metal-chelating capability of the compounds.

Antioxidants↗
PubMed2000

Antioxidative galloyl esters as enzyme inhibitors of p-hydroxybenzoate hydroxylase.

Gallic acid and its esters were evaluated as enzyme inhibitors of recombinant p-hydroxybenzoate hydroxylase (PHBH), a NADPH-dependent flavin monooxygenase from Pseudomonas aeruginosa. n-Dodecyl gallate (DG) (IC(50)=16 microM) and (-)-epigallocatechin-3-O-gallate (EGCG) (IC(50)=16 microM), a major component of green tea polyphenols, showed the most potent inhibition, while product-like gallic acid did not inhibit the enzyme significantly (IC(50)>250 microM). Inhibition kinetics revealed that both DG and EGCG inhibited PHBH in a non-competitive manner (K(I)=18.1 and 14.0 microM, respectively). The enzyme inhibition was caused by specific binding of the antioxidative gallate to the enzyme, and by scavenging reactive oxygen species required for the monooxygenase reaction. Molecular modeling predicted that EGCG binds to the enzyme in the proximity of the FAD binding site via formation of three hydrogen bonds.

4-Hydroxybenzoate-3-Monooxygenase↗
PubMed2005

Anti-diarrheal effect of Galla Chinensis on the Escherichia coli heat-labile enterotoxin and ganglioside interaction.

Enterotoxigenic Escherichia coli (ETEC) is the most frequently isolated enteropathogen, accounting for approximately 210 million diarrhea episodes annually. ETEC-induced diarrhea is initiated by the binding of B subunit of heat-labile enterotoxin (LTB) to the ganglioside G(M1) on the surface of intestinal epithelial cell. Therefore, we evaluated the inhibitory effects of 297 Chinese medicinal herbs on the LTB and G(M1) interaction by G(M1)-enzyme-linked immunosorbent assay. Galla Chinensis extract (GCE) exhibited anti-LT-induced diarrheal effect in the patent mouse gut assay, with IC50 value of 4.7+/-1.3 mg/ml. GCE also inhibited the binding of LTB to G(M1), suggesting that GCE suppressed the LT-induced fluid accumulation by blocking the binding of LTB to G(M1). Furthermore, the ethyl acetate (EA) soluble fraction was the most active fraction of Galla Chinensis that inhibiting the binding of LTB to G(M1) with an IC50 value of 153.6+/-3.4 microg/ml. The major components of the EA fraction should be phenolic derivatives according to a thin-layer chromatography analysis. Gallic acid, the major component of EA fraction, blocked the binding of LTB to G(M1), resulting in the suppression of LT-induced diarrhea. In conclusion, these data suggested that Galla Chinensis and gallic acid might be potent drugs for the treatment of LT-induced diarrhea.

Animals↗
PubMedDate not supplied

Interaction between sodium ascorbate and polyphenols.

The interaction between sodium ascorbate and polyphenols was investigated by two different parameters: radical intensity and cytotoxicity induction. ESR spectroscopy shows that sodium ascorbate, lignins (alkali-lignin, lignin sulfonate, pine cone-derived lignin) and tannins (gallic acid, epigallocatechin gallate (EGCg), tannic acid) all produced radicals with different intensities under alkaline conditions. All lignin samples significantly enhanced the radical intensity and cytotoxic activity of sodium ascorbate, whereas all tannin samples slightly reduced the radical intensity of sodium ascorbate. Sodium ascorbate efficiently scavenged the radical and cytotoxic activity of gallic acid, as expected by the ionization potential and heat of reaction by the PM3 semiempirical method. EGCg and tannic acid slightly reduced the cytotoxic activity of sodium ascorbate. The present study demonstrates that lignins and tannins modify the radical intensity and cytotoxic activity of sodium ascorbate in different manners, and suggests the applicability of ESR spectroscopy for the screening of drug to drug interaction.

Ascorbic Acid↗
PubMed2005

Strain improvement for tannase production from co-culture of Aspergillus foetidus and Rhizopus oryzae.

Spores from the co-culture of Aspergillus foetidus and Rhizopus oryzae were subjected to UV, heat and NTG (3-nitro,5-methylguanidine) mutagenesis. A few colonies were screened from the selected media for tannase study. Amongst all, the best mutant isolated from the heat treatment (60 degrees C for 60 min) was SCPR 337. The maximum yield of gallic acid and tannase in case of mutant strain was 95.2% and 53.6 U/ml with an incubation period of 30 h as compared to wild strain where the incubation period was 48 h with an enzyme activity of 44.2 U/ml and gallic acid yield of 94%, respectively. The mutant was sensitive to tetracycline and was also an over-producer of protease and amylase.

Amylases↗
PubMed2004

Analysis of polyphenolic antioxidants in star fruit using liquid chromatography and mass spectrometry.

Our previous study indicated that star fruit (Averrhoa carambola L.) is a very good source of natural antioxidants. However, it was still not clear which compounds were responsible for its antioxidant properties. The purpose of this study is to separate and identify compounds that contribute to total antioxidant activity in star fruit using HPLC and mass spectrometry (MS). HPLC coupled with a diode array detector (DAD) was used to characterise antioxidant peak in the juice or residue extract through spiking with free radicals. By analysing the antioxidant capacity and chromatograms of fractions from solid phase extraction, main antioxidants were attributed to phenolic compounds. The peaks were identified as L-ascorbic acid, (-)epicatechin and gallic acid in gallotannin forms. Other antioxidant peaks were further investigated using HPLC-ESI-MS-MS. Identification was confirmed with electronspray ionisation (ESI) MS-MS spectra of pure standards and singly-linked proanthocyanidins from pycnogenol. The major antioxidants were initially attributed to singly-linked proanthocyanidins that existed as dimers, trimers, tetramers and pentamers of catechin or epicatechin.

Antioxidants↗
PubMed2005

Bioactive ellagitannins from Cunonia macrophylla, an endemic Cunoniaceae from New Caledonia.

Chemical study of Cunonia macrophylla, a New Caledonian Cunoniaceae, based on bioactive effects of a crude methanol extract of the leaves, detected bioactive tannins for the first time in this plant family. These ellagitannins have been identified as ellagic acid-4-O-beta-D-xylopyranoside (6), mallorepanin (3), mallotinic acid (1) along with corilagin (2), chebulagic acid (4), ellagic acid (5) and gallic acid (7) and have been shown to possess antimicrobial activity and to inhibit xanthine oxidase. Antimicrobial effects on bacterial human pathogens (Staphylococcus aureus, Corynebacterium accolans) and on a plant pathogen (Erwinia carotovora) as well as on a human pathogenic yeast (Candida albicans) were investigated. Activity is reported here for the first time for compounds 1, 3, 4 and 6. The inhibitory effects of all molecules against xanthine oxidase in relation to their structure was evaluated and compared. Compound 6 presented the best activity and seems to be of considerable interest for further studies.

Anti-Infective Agents↗
PubMed1996

Capillary electrophoretic determination of the constituents of paeoniae radix.

A method combining the techniques of capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) has been developed to separate a total of eight peony constituents. The CZE method was used to determine the content of paeonol, oxypaeoniflorin, benzoic acid, pentagalloylglucose and gallic acid, and MEKC technique based on sodium cholate was applied to analyze albiflorin, paeoniflorin, benzoyla biflorin, paeonol and oxypaeoniflorin. Linearity around two orders of magnitude of concentration was generally obtained and limits of detection for these compounds were in the range of 2.6-23.7 micrograms/ml. The relative standard deviations of migration times were less than 1.43% (n = 6). Contents of peony constituents in an ethanol-water extract of Paeonia lactiflora Pall. sample could easily be determined by this method.

Chromatography, Liquid↗
PubMed2004

HPLC-MSn analysis of phenolic compounds and purine alkaloids in green and black tea.

Tea is a complex mixture containing a range of compounds from simple phenolics to complex thearubigins, many of which have well-recognized antioxidant properties. This paper describes the application of high-performance liquid chromatography-mass spectrometry (HPLC-MS(n)) methods for the rapid and routine analysis of more than 30 phenolics in tea. Green and black tea infusions were injected directly onto a reversed phase HPLC column, and the phenolics eluted using two different mobile phase gradients, one optimized to resolve catechin derivatives and the other, flavonols and theaflavins. Compounds, identified on the basis of their retention time, absorbance spectrum, and MS fragmentation pattern, included (+)-catechin, (-)-epicatechin, theaflavin and their various gallate derivatives, quercetin and kaempferol mono-, di-, and triglycosides, quinic acid esters of gallic acid and hydroxycinnamates, and the purine alkaloids, caffeine and theobromine.

Biflavonoids↗
PubMed1999

Free radical scavenging capacity in the aging of selected red Spanish wines.

Free radical scavenging capacity by the DPPH(*) method and main physicochemical properties, polyphenols content by HPLC, color by a tristimulus colorimeter, and UV-vis spectra in the aging of selected red Spanish wines, were studied. As the wines age, they become darker (lower lightness, L) and increase their hue angle (lower red color) as well as the ratio of absorbance at 420 nm to that at 520 nm. Main polyphenolics identified in the samples were tannic acid, oenin, and gallic acid. The antiradical efficiency of the samples increased during aging, which could be related to an increase in the tannic acid concentration shown by the following correlationship: EC(50) = 1/(0.18 + 0.0011[tannic acid](mg/L)) with a correlation coefficient of 0.744.

Chromatography, High Pressure Liquid↗
PubMed1997

Identity and biodegradative abilities of yeasts isolated from plants growing in an arid climate.

Plants harvested in the Canary Islands Lanzarote and Fuerteventura were analyzed for the yeasts inhabiting their surface. Half of the isolates (22 out of 44) were identified as Debaryomyces hansenii. Black ascomycetes, viz. Hortaea werneckii and two Hormonema species were represented by 7 strains. Basidiomycetous yeasts, viz. Cryptococcus sp. (8 strains), Rhodotorula sp. (5 strains), Cerinosterus cyanescens (1 strain) and Pseudozyma sp. (1 strain) constituted a minority of 33%. Thirty strains were screened for their ability to assimilate various plant constituents including lipids of the cuticle and the cell membrane, hemicelluloses, nitrogenous compounds (protein, nucleic acids, amino acids) and benzene compounds. All strains were able to assimilate or to hydrolyze lipids, lecithin included. Many strains of D. hansenii, H. dematioides, H. werneckii, C. cyanescens, Cr. laurentii, Pseudozyma sp. and Rh. glutinis were proteolytic. Hemicelluloses like xylan and pectin were assimilated by black ascomycetous yeasts, Cryptococcus sp., Pseudozyma sp. and Rh. glutinis. Ferulic and hydroxycinnamic acids, gallic and tannic acids were assimilated by some strains of H. dematioides, C. cyanescens, Pseudozyma sp. and Rhodotorula sp.

Amino Acids↗
PubMed2001

Antibacterial action of several tannins against Staphylococcus aureus.

We examined the antibacterial action of several tannins on plasma coagulation by Staphylococcus aureus and the effect of conventional chemotherapy combined with tannic acid below the MIC. Coagulation was inhibited in plasma containing tannic acid (100 mg/L), gallic acid (5000 mg/L), ellagic acid (5000 mg/L), (-)-epicatechin (1500 mg/L), (-)-epicatechin gallate (500 mg/L) or (-)-epigallocatechin gallate (200 mg/L) after incubation for 24 h. All tannins inhibited coagulation at a concentration below the MIC. The MICs of oxacillin and cefdinir for S. aureus were reduced to < or = 0.06 mg/L in Mueller-Hinton agar plates with tannic acid (100 mg/L) at a concentration below the MIC. The antistaphylococcal activity of tannic acid was reduced in plates with 10% rabbit blood, but not in those with 10% rabbit plasma. Membranous structures formed in a culture medium containing equal proportions of plasma and tryptic soy broth after incubation for 24 h. The colony counts of S. aureus in membranous structures in the medium containing oxacillin (40 mg/L) and tannic acid (100 mg/L) were c. 10-fold lower than those in medium containing oxacillin (40 mg/L) alone (P < 0.01). Tannic acid merits further investigation as a possible adjuvant agent against S. aureus skin infections treated with beta-lactam antibiotics.

Anti-Bacterial Agents↗
PubMed1989

Dietary phenolic compounds: inhibition of Na+-dependent D-glucose uptake in rat intestinal brush border membrane vesicles.

The effects of phenolic compounds on Na+-dependent D-glucose transport were investigated in brush border membrane vesicles isolated from rat small intestine. Screening experiments were conducted with different classes of phenolic compounds in both their native and oxidized forms. Pretreatment of vesicles with tannic acid (1 mg/ml) completely abolished the characteristic overshoot of active glucose accumulation. With chlorogenic acid (1mM), 80% of the glucose transport capacity was lost. Reductions of 30-40% were observed in vesicles treated with catechin, ferulic or caffeic acids. Treatment with gallic acid (1 mM) had little effect. Phenolic oxidation state did not exacerbate the degree of glucose transport inhibition, with the exception of catechol (1 mM), which gave maximal inhibition (86%) in its oxidized form. Gradient-independent glucose uptake was not altered, nor did phenolic treatment increase nonspecific binding of glucose to the membrane vesicles. Possible mechanisms of D-glucose transport inhibition were examined in chlorogenic acid-and tannic acid-treated vesicles. Factors such as alterations in vesicle permeability, size and leakage of transported glucose out of the vesicles were ruled out. Measurements of D-glucose uptake under conditions of Na+ equilibrium suggest that tannic and chlorogenic acids reduce glucose uptake by favoring the dissipation of the Na+ electrochemical gradient, which provides the driving force for active glucose accumulation.

Animals↗
PubMed2003

Red wine polyphenolics increase LDL receptor expression and activity and suppress the secretion of ApoB100 from human HepG2 cells.

Epidemiologic studies suggest that the consumption of red wine may lower the risk of cardiovascular disease. The cardioprotective effect of red wine has been attributed to the polyphenols present in red wine, particularly resveratrol (a stilbene, with estrogen-like activity), and the flavonoids, catechin, epicatechin, quercetin and phenolic acids such as gallic acid. At present, very little is known about the mechanisms by which red wine phenolic compounds benefit the cardiovascular system. Therefore, the aim of this study was to elucidate whether red wine polyphenolics reduce lipoprotein production and clearance by the liver. Cultured HepG2 cells were incubated in the presence of dealcoholized red wine, alcohol-containing red wine and atorvastatin for 24 h. The apolipoprotien B100 (apoB100) protein (marker of hepatic lipoproteins) was quantified on Western blots with an anti-apoB100 antibody and the enhanced chemiluminescence detection system. Apolipoprotein B100 levels in the cells and that secreted into the media were significantly reduced by 50% in liver cells incubated with alcohol-stripped red wine compared with control cells. This effect of dealcoholized red wine on apoB100 production in HepG2 cells was similar to the effect of atorvastatin. Apo B100 production was significantly attenuated by 30% in cells incubated with alcoholized red wine, suggesting that the alcohol was masking the effect of red wine polyphenolics. Apo B100 production was significantly attenuated by 45% with the polyphenolic compounds resveratrol and quercertin. In addition, dealcoholized and alcoholized red wine and atorvastatin significantly increased 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase mRNA and LDL receptor binding activity relative to controls. Dealcoholized red wine also increased LDL receptor gene expression. Collectively, this study suggests that red wine polyphenolics regulate major pathways involved in lipoprotein metabolism.

Apolipoprotein B-100↗
PubMed2002

Isolation from a shea cake digester of a tannin-degrading Streptococcus gallolyticus strain that decarboxylates protocatechuic and hydroxycinnamic acids, and emendation of the species.

A facultatively anaerobic, mesophilic, non-motile, non-sporulating bacterium, designated strain B7, was isolated from an anaerobic digester fed with shea cake rich in tannins and aromatic compounds, after enrichment on tannic acid. The coccoid cells (less than 2 microm in diameter) occurred in pairs or short chains and stained gram-positive. Strain B7 fermented a wide range of carbohydrates (cellobiose, fructose, galactose, glucose, lactose, maltose, mannitol, melibiose, raffinose and trehalose), grew optimally at pH 7.0 and had a G+C content of 40.4+/-0.3 mol%. Strain B7 was closely related to Streptococcus gallolyticus ACM 3611T, a member of the Streptococcus bovis rRNA cluster, with a sequence similarity of 98% and a DNA hybridization value of 86 mol%. Isolate B7 hydrolysed tannic acid and decarboxylated gallic acid to pyrogallol, traits also observed in S. gallolyticus ACM 3611T. In addition, both strains decarboxylated protocatechuic acid to catechol, p-coumaric acid to 4-vinylphenol, caffeic acid to 4-vinylcatechol and ferulic acid to 4-vinylguaiacol. An unsubstituted para-hydroxyl group on the benzene ring was required for decarboxylation. Glucose addition markedly increased the conversion rate. As these traits were not described previously, emendation of the description of the species Streptococcus gallolyticus is proposed.

Anaerobiosis↗
PubMed1998

Anti-Helicobacter pylori activity of herbal medicines.

The extracts of Coptidis japonica (rhizoma), Eugenia caryophyllata (flower), Rheum palmatum (rhizoma), Magnolia officinalis (cortex) and Rhusjavanica (galla rhois) potently inhibited the growth of Helicobacter pylori (HP). However, these herbal extracts showed no inhibitory effect on HP urease except Galla rhois. Among the components separated from active herbal extracts by silica gel column chromatography, the inhibitory effects of decursinol angelate and decursin on the growth of HP were the most potent, followed by magnolol, berberine, cinnamic acid, decursinol and gallic acid. Minimum inhibitory concentrations (MICs) of decursin and decursinol angelate were 6-20 microg/ml.

Enzyme Inhibitors↗