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PubMed2001

Antimicrobial activity of Argentine plants used in the treatment of infectious diseases. Isolation of active compounds from Sebastiania brasiliensis.

Different extracts of Sebastiania brasiliensis, Sebastiania klotszchiana, Polygonum punctatum, Lithraea molleoides and Myrcianthes cisplatensis, all plants growing in Entre Ríos Province and traditionally used as antiseptics, were tested against a set of Gram positive and Gram negative bacteria and fungi. All the species, with the exception of M. cisplatensis, presented activity against some of the microorganisms tested. A 50% hydroalcoholic extract of S. brasiliensis was selected for bioguided fractionation. Two antimicrobial compounds identified as methylgallate (MIC 128 microg/ml) and protocatechuic acid (MIC 128 microg/ml) were isolated apart from quercetin, kaempferol, quercitrin and gallic acid.

Anti-Bacterial Agents↗

PubMedDate not supplied

Qualitative and quantitative analysis of phenolic acids in Asclepias syriaca L.

TLC and HPLC was applied to qualitative and quantitative determination of phenolic acids free and liberated by acid and alkaline hydrolysis in common milkweed. The presence of phenolic acids, namely p-hydroxybenzoic, p-coumaric, protocatechuic and caffeic acids, was confirmed in the leaves and flowers. Moreover, the flowers contained gallic acid, and the leaves contained alpha-resorcylic, vanilic and chlorogenic acids. Conjugated forms of phenolic acids predominate in the plant. They hydrolyse mainly to coffeic, p-coumaric, ferulic and p-hydroxybenzoic acids.

Chromatography, High Pressure Liquid↗

PubMed2006

Development of a stable isotope dilution analysis with liquid chromatography-tandem mass spectrometry detection for the quantitative analysis of di- and trihydroxybenzenes in foods and model systems.

A straightforward stable isotope dilution analysis (SIDA) for the quantitative determination of the di- and trihydroxybenzenes catechol (1), pyrogallol (2), 3-methylcatechol (3), 4-methylcatechol (4), and 4-ethylcatechol (5) in foods by means of liquid chromatography-tandem mass spectrometry was developed. With or without sample preparation involving phenylboronyl solid phase extraction, the method allowed the quantification of the target compounds in complex matrices such as coffee beverages with quantification limits of 9 nmol/L for 4-ethylcatechol, 24 nmol/L for catechol, 3-methyl-, and 4-methylcatechol, and 31 nmol/L for pyrogallol. Recovery rates for the analytes ranged from 97 to 103%. Application of the developed SIDA to various commercial food samples showed that quantitative analysis of the target compounds is possible within 30 min and gave first quantitative data on the amounts of di- and trihydroxybenzenes in coffee beverage, coffee powder, coffee surrogate, beer, malt, roasted cocoa powder, bread crust, potato crisps, fruits, and cigarette smoke and human urine. Model precursor studies revealed the carbohydrate/amino acid systems as well as the plant polyphenols catechin and epicatechin as precursors of catechol and 5-O-caffeoylquinic acid, caffeic acid as a precursor of catechol and 4-ethylcatechol, and gallocatechin, epigallocatechin, and gallic acid as precursors of pyrogallol.

Catechols↗

PubMed1975

Novel pathway for degradation of protocatechuic acid in Bacillus species.

A species of Bacillus, tentatively identified as B. circulans, degrades protocatechuic acid by a novel reaction involving meta-fission between C2 and C3 of the benzene nucleus. 2-Hydroxymuconic semialdehyde is then degraded to pyruvate and acetaldehyde by enzymatic reactions described in previous work. Protocatechuate 2,3-oxygenase exhibits a rather narrow substrate specificity; the methyl and ethyl esters of protocatechuic acid are oxidized, but other substrates for ring-fission oxygenases, notably catechol, gallic acid, and homoprotocatechuic acid, are not attached.

Acetaldehyde↗

PubMed1975

[On the phenolic acids of vegetables. IV. Hydroxycinnamic acids and hydroxybenzoic acids of vegetables and potatoes (author's transl)].

Lettuce, endive and chicory exclusively, cornsalad and sweet fennel almost exclusively contain caffeic acid derivatives beside traces of ferulic acid. Parsley exclusively and spinach almost exclusively show p-coumaric acid derivatives. Compared to root, fruit and seed vegetables the contents of phenolic acids in green leaves are considerably high. Rhubarb is the only vegetable, which contains gallic acid (chief phenolic acid) beside hydroxycinnamic, protocatechuic and vanillic acid derivatives. Furthermore hydroxybenzoic acid derivatives (salicylic, gentisic and vanillic acid) occur in cornsalad, sweet fennel, parsley and spinach in small concentrations; cornsalad shows p-hydroxybenzoic acid (ca. 20 mg/kg). Onions (Allium cepa) contain almost only protocatechuic acid beside small amounts of p-hydroxybenzoic and vanillic acid. In the outer dry coloured skins protocatechuic acid reaches concentrations up to 2% of plant material; the internal pulpy tissues show lower concentrations (ca. 20 mg/kg). On the contrary to the bulbs the green leaves of onions like chive and leek contain almost exclusively compounds of ferulic and p-coumaric acid. Garlic even shows a different phenolic acid pattern of skins and internal tissues. The caffeic acid derivatives of potatoes are mainly localized to a 1--2 mm thick outer layer. The different localization of phenolic acids in the different parts of vegetable plants is discussed.

Caffeic Acids↗

PubMed2003

Unique phenolic carboxylic acids from Sanguisorba minor.

The unique phenolic carboxylic acids, 4,8-dimethoxy-7-hydroxy-2-oxo-2H-1-benzopyran-5,6-dicarboxylic acid and 2-(4-carboxy-3-methoxystyryl)-2-methoxysuccinic acid were isolated and identified from the whole Sanguisorba minor plant. The known phenolics, gallic acid; ellagic acid; quercetin-3-O-(6"-galloylglucose); beta-glucogallin; 2,3-hexahydroxydiphenoyl-(alpha/beta)-glucose; 1-galloyl-2,3-hexahydroxydiphenoyl-alpha-glucose together with its beta-isomer were also characterized. Structures were established by conventional methods of analysis and confirmed by NMR and ESI-MS spectral analysis.

Carboxylic Acids↗

PubMed2001

[Studies on chemical constituents in root of Rumex patientia L].

OBJECTIVE: Investigating the chemical constituents in the root of Rumex patientia. METHOD: Compounds were separated by rechromatography on silica gel. Their structures were determined by spectral analysis and chemical evidence. RESULT: Eight compounds were isolated and identified as 5-methoxy-7-hydroxy-1 (3H)-benzofuranone (I), 5, 7-dihydroxy-1 (3H)-benzofuranone(II), nonadecanoic acid-2,3-dihydroxypropyl ester(III), torachrysone-8-O-beta-D-glucopyranoside(IV), gallic acid(V), beta-sitosterol(VI), beta-sitosterol-3-O-beta-D-glucopyranoside(VII) and catechin(VIII). CONCLUSION: Compound III is a new natural products, and compounds I and II were obtained from this plant for the first time.

Benzofurans↗

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↗

PubMed2005

Anti-inflammatory and antioxidant activity of a medicinal tincture from Pedilanthus tithymaloides.

Pedilanthus tithymaloides (L.) Poit. (Euphorbiaceae) is a low tropical American shrub with a reported wide range of healing properties such as emetic, anti-inflammatory, antibiotic, antiseptic, antihemorrhagic, antiviral, antitumoral, and abortive. In the present study, a tincture from P. tithymaloides collected in Cuba was evaluated for its in vivo anti-inflammatory activity, using the rat paw oedema assay, and for its in vitro scavenging effects on reactive oxygen species (ROS) (HO*, O2*-, HOCl, ROO* and H2O2), reactive nitrogen species (RNS) (ONOO- and *NO), and DPPH* radical. The protein, free amino acid, and phenolic contents of the tincture were also determined. Pertaining to the anti-inflammatory activity, the intraperitoneal administration of the tincture inhibited carrageenan-induced rat paw oedema, whereas in the scavenging assays the tincture showed to be effective against all the assayed ROS and RNS, specially for HO* (IC50 = 345+/-77 microg/mL), O2*- (IC50 = 143+/-7 microg/mL), HOCl (IC50 = 113+/-20 microg/mL), ONOO- (IC50 = 44+/-3 microg/mL), and *NO (IC50 = 54+/-4 microg/mL), but displayed weak activity in the DPPH* assay. The protein content of the tincture was 0.70%, and twenty free amino acids were identified and quantified. The content of total phenolics was 17.4+/-0.15 mg of gallic acid equivalents (GAE)/g dry material. These results provide scientific support for the empirical use of P. tithymaloides tincture as an anti-inflammatory medicine.

Animals↗

PubMed2002

Antioxidant properties of Thonningianin A, isolated from the African medicinal herb, Thonningia sanguinea.

The antioxidant properties of Thonningianin A (Th A), an ellagitannin, isolated from the methanolic extract of the African medicinal herb, Thonningia sanguinea were studied using the NADPH and Fe2+/ascorbate-induced lipid peroxidation (LPO), electron spin resonance spectrometer and the deoxyribose assay. Th A at 10 microM inhibited both the NADPH and Fe2+/ascorbate-induced LPO in rat liver microsomes by 60% without inhibitory effects on cytochrome P450 activity. Th A was similar to the synthetic antioxidant, tannic acid, as an inhibitor of both the NADPH and Fe2+/ascorbate-induced LPO but potent than gallic acid, vitamin C and vitamin E. While Th A poorly scavenged the hydroxyl radical generated by the Fenton reaction it dose-dependently scavenged 1,1-diphenyl-2-picrylhydrazyl, superoxide anion and peroxyl radicals with IC50 of 7.5, 10 and 30 microM, respectively. Furthermore, Th A showed inhibitory effects on the activity of xanthine oxidase with an IC50 of 30 microM. In the deoxyribose assay both T. sanguinea and its methanolic component Th A showed only site-specific (Fe3+ + H2O2) but not non-site-specific (Fe3+ + EDTA + H2O2) hydroxyl radical scavenging suggesting chelating ability for iron ions. Spectroscopic studies showed that Th A enhanced absorbance in the visible region in the presence of Fe2+ ions. These results indicate that the antioxidant properties of Th A involve radical scavenging, anti-superoxide formation and metal chelation.

Animals↗

PubMed1999

Chitosan treatment of wheat seeds induces resistance to Fusarium graminearum and improves seed quality.

Chitosan treatment (2-8 mg/mL) of wheat seeds significantly improved seed germination to recommended seed certification standards (>85%) and vigor at concentrations >4 mg/mL, in two cultivars of spring wheat (Norseman and Max), by controlling seed-borne Fusarium graminearum infection. The germination was <80% in the control and >85% in benomyl- and chitosan-treated seeds. Seed-borne F. graminearum was reduced to >50% at higher chitosan treatments compared to the control. Synthesis of phenolic acids was stimulated in primary leaves following chitosan treatment, and levels of these phenolic acids, especially ferulic acid, increased significantly with increasing chitosan concentration. Lignin content of primary leaves also showed a similar pattern. The synthesis of precursors of lignin such as p-coumaric, ferulic, and sinapic acids and phenolic acids having antimicrobial activity such as benzoic, p-coumaric, caffeic, protocatechuic, chlorogenic, ferulic, and gallic acids was also stimulated by chitosan treatment. The induction of phenolic acids and lignin was significantly lower in cv. Max compared to Norseman. Chitosan also inhibited fungal transmission to the primary roots of germinating seedlings. Results suggest that chitosan controlled seed-borne F. graminearum infection and increased the resistance in seedlings by stimulating the accumulation of phenolics and lignin. Thus, chitosan has a potential for improvement of seed quality and enhancement of crop yields as well as increased value of stored grains for food and feed.

Benomyl↗

PubMed2005

[Studies on the chemical constituents in herb of Ludwigia octovalvis].

OBJECTIVE: To study the chemical constituents of the herb of Ludwigia octovalvis. METHOD: Chemical constituents were isolated by the repeated silica gel column chromatography, and their structures were elucidated by the physicochemical properties and spectral analysis. RESULT: Thirteen compounds were obtained and determined as follows: beta-sitosterol (1), oleanolic acid (2), 2alpha-hydroxy ursolic acid (3), tormentic acid (4), daucosterol (5), maltol (6), luteolin (7), quercetin (8), apigenin (9), methyl brevifolincarboxylate (10), gallic acid (11), 3, 4, 8, 9, 10-pentahydroxydibenzo[b, d]pyran-6-one (12), and ellagic acid (13). CONCLUSION: Compounds 3, 4, 6-13 were isolated from the plant for the first time. And compounds 3, 4, 6, 10, 12 were obtained from the genus for the first time.

Molecular Structure↗

PubMed2005

Phenolics as potential antioxidant therapeutic agents: mechanism and actions.

Accumulating chemical, biochemical, clinical and epidemiological evidence supports the chemoprotective effects of phenolic antioxidants against oxidative stress-mediated disorders. The pharmacological actions of phenolic antioxidants stem mainly from their free radical scavenging and metal chelating properties as well as their effects on cell signaling pathways and on gene expression. The antioxidant capacities of phenolic compounds that are widely distributed in plant-based diets were assessed by the Trolox equivalent antioxidant capacity (TEAC), the ferric reducing antioxidant power (FRAP), the hypochlorite scavenging capacity, the deoxyribose method and the copper-phenanthroline-dependent DNA oxidation assays. Based on the TEAC, FRAP and hypochlorite scavenging data, the observed activity order was: procyanidin dimer>flavanol>flavonol>hydroxycinnamic acids>simple phenolic acids. Among the flavonol aglycones, the antioxidant propensities decrease in the order quercetin, myricetin and kaempferol. Gallic acid and rosmarinic acid were the most potent antioxidants among the simple phenolic and hydroxycinnamic acids, respectively. Ferulic acid displayed the highest inhibitory activity against deoxyribose degradation but no structure-activity relationship could be established for the activities of the phenolic compounds in the deoxyribose assay. The efficacies of the phenolic compounds differ depending on the mechanism of antioxidant action in the respective assay used, with procyanidin dimers and flavan-3-ols showing very potent activities in most of the systems tested. Compared to the physiologically active (glutathione, alpha-tocopherol, ergothioneine) and synthetic (Trolox, BHA, BHT) antioxidants, these compounds exhibited much higher efficacy. Plant-derived phenolics represents good sources of natural antioxidants, however, further investigation on the molecular mechanism of action of these phytochemicals is crucial to the evaluation of their potential as prophylactic agents.

Antioxidants↗

PubMed2006

Modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (abts) method to measure antioxidant capacity of Selected small fruits and comparison to ferric reducing antioxidant power (FRAP) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods.

The measurement of antioxidant capacity in fruits differs from that of other biological samples due to their low pH and very low lipophilic antioxidant capacity. In this report, we present a modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method for fruits and compare its performance with the other commonly used antioxidant methods of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The antioxidant capacity and reaction kinetics of four phenolic compounds, two antioxidant standards, and five fruits were also investigated. The modified ABTS method prepared at a pH of 4.5 with sodium acetate buffer is highly stable and easily applied to fruit samples as compared to the standard (pH 7.4) version. The measured antioxidant capacity of samples varied with the assay method used, pH, and time of reaction. Traditional antioxidant standards (trolox, ascorbic acid) displayed stable, simple reaction kinetics, which allowed end point analysis with all of assays. Of the phenolic compounds examined, chlorogenic and caffeic acids exhibited the most complex reaction kinetics and reaction rates that precluded end point analysis while gallic acid and quercetin reached stable end points. All fruit extracts exhibited complex and varied kinetics and required long reaction times to approach an end point. Because the antioxidant capacity of fruit extracts is a function of the array of individual antioxidants present, accurate comparisons among fruit samples require that reaction times be standardized and of sufficient length to reach steady state conditions and that more than one assay be used to describe the total antioxidant activity of fruit samples.

Antioxidants↗

PubMed1994

Degradation of polyphenols (catechin and tannic acid) in the rat intestinal tract. Effect on colonic fermentation and faecal output.

Low- and intermediate-molecular-weight polyphenols are usually extracted by using different solvents (e.g. water, methanol, aqueous acetone). The aim of the present work was to study the possible effects of some extractable polyphenols (EPP) on fat and protein digestibilities and on the colonic microflora. Degradability of these compounds through the intestinal tract was also studied. Catechin and tannic acid (TA) were chosen as representatives of the most common basic structures of EPP (flavonoids and gallic acid respectively). Three groups of eight male Wistar rats were given either a control diet free of EPP, or diets containing 20 g/kg dry matter of catechin and TA. Body-weight and food intake were monitored during a 3-week experimental period. Faeces and urine were collected daily during the third experimental week. EPP and fat were determined in faeces, and N in both urine and faeces. Only 3.1 and 4.6% of the ingested catechin and TA respectively were excreted in faeces, indicating that absorption and/or degradation of these EPP had occurred. HPLC analysis of the polyphenolic content of faeces showed qualitative differences between groups. A significant increase of total faecal weight as well as water, fat and N excretion was produced by TA. Catechin only caused an increase in fat excretion. In vitro fermentation assays were also performed to study the effect of EPP on the colonic microflora. Both catechin and TA affected the yield of end-products of fermentation, and were also degraded during the fermentation process.

Animals↗

PubMedDate not supplied

Induction of apoptosis by cooperative action of vitamins C and E.

Millimolar concentrations of sodium ascorbate (vitamin C) induced apoptotic cell death in human promyelocytic leukemic HL-60 cells. The apoptotic cells displayed a smaller cell volume, disappearance of cell surface microvilli, appearance of cytoplasmic vacuoles, chromatin condensation, nuclear fragmentation and production of apoptotic bodies. The apoptosis-inducing activity of sodium ascorbate was significantly enhanced by noncytotoxic concentrations of CuCl2, but was almost completely eliminated by FeCl3. CuCl2 transiently stimulated the hydrogen peroxide (H2O2) production by sodium ascorbate, whereas FeCl3 slightly reduced the H2O2 production. alpha-Tocopherol (vitamin E) slightly enhanced the radical and H2O2 productions, and apoptosis induction by sodium ascorbate. The effect of alpha-tocopherol seems to be rather specific for ascorbic acid, since alpha-tocopherol did not significantly affect the cytotoxic activity of CuCl2, FeCl3 nor gallic acid. The present study demonstrated the cooperative action of vitamins C and E.

Antioxidants↗

PubMed2006

Tannic acid synergizes the cytotoxicity of chemotherapeutic drugs in human cholangiocarcinoma by modulating drug efflux pathways.

BACKGROUND/AIMS: Tannic acid is an orally active plant polyphenol with potential for use as an anti-cancer agent for cholangiocarcinoma. To determine the potential use of tannic acid as an adjunct therapy, we sought to evaluate the interaction between tannic acid and chemotherapeutic agents. METHODS: Cytotoxicity was assessed in malignant human cholangiocytes. Interactions between tannic acid, mitomycin C, 5-fluorouracil and gemcitabine were quantitated by calculating the combination index and dose reduction index. Cellular efflux pathways were assessed by calcein retention assays, and expression of membrane pumps was assessed by Western blots and real-time PCR. RESULTS: Tannic acid and the three agents decreased growth of malignant cholangiocytes to a similar extent. Tannic acid had a synergistic effect to mitomycin C and 5-fluorouracil, but not gemcitabine. However, the structurally related polyphenol gallic acid did not have a synergistic interaction with any of the agents. Tannic acid decreased calcein efflux and the expression of PGP, MRP1 and MRP2 membrane efflux pumps. CONCLUSIONS: Tannic acid has a synergistic effect with selected chemotherapeutic drugs by a mechanism involving modulation of drug efflux pathways. Thus, tannic acid will be a useful adjunct to improve the effectiveness of chemotherapeutic agents in the treatment of cholangiocarcinoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2006

Three new pentacyclic triterpenes and some flavonoids from the fruits of an Indian Ayurvedic plant Dendrophthoe falcata and their estrogen receptor binding activity.

Extensive chromatographic screening of extracts of the fruits of the Indian Ayurvedic plant, Dendrophthoe falcata, resulted in the isolation of three new triterpenes, 3beta-acetoxy-1beta-(2-hydroxy-2-propoxy)-11alpha-hydroxy-olean-12-ene (1), 3beta-acetoxy-11alpha-ethoxy-1beta-hydroxy-olean-12-ene (2) and 3beta-acetoxy-1beta-hydroxy-11alpha-methoxy-olean-12-ene (3) along with nine known compounds, 3beta-acetoxy-1beta,11alpha-dihydroxy-olean-12-ene (4), 3beta-acetoxy-1beta,11alpha-dihydroxy-urs-12-ene (5), 3beta-acetoxy-urs-12-ene-11-one (6), 3beta-acetoxy-lup-20(29)-ene (7), 30-nor-lup-3beta-acetoxy-20-one (8), (20S)-3beta-acetoxy-lupan-29-oic acid (9), kaempferol-3-O-alpha-L-rhamnopyranoside (10), quercetin-3-O-alpha-L-rhamnopyranoside (11), and gallic acid (12). The structures of these compounds were determined using 1D and 2D NMR and high resolution electrospray mass spectrometry. These compounds were assayed for binding to estrogen receptors-alpha and beta and kaempferol-3-O-alpha-L-rhamnopyranoside (10) was found to be a ligand for both receptors with greater affinity for beta. The triterpenes (1-9) are reported for the first time in the genus Dendrophthoe and assumes taxonomic significance.

Flavonoids↗