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PubMed1998

Determination of anti-carcinogenic polyphenols present in green tea using capillary electrophoresis coupled to a flow injection system.

A capillary electrophoresis (CE) method was developed for the simultaneous determination of a number of major ingredients of green tea. The components analysed were caffeine, adenine, theophylline, epigallocatechin-3 gallate, epigallocatechin, epicatechin-3 gallate, (-)-epicatechin, (+)-catechin, gallic acid, quercetin and caffeic acid. Separation was achieved using a fused capillary column with 0.15 M H3BO3 as buffer at a pH of 8.5, UV detection at 210 nm and 20 kV of voltage. Analysis was carried out after treatment (extraction, filtration and dilution) of the samples in a flow injection system which was coupled to a CE equipment via a programmable arm. The procedure allows the determination of these compounds in less than 20 min. Quantitative analysis was performed by the standard addition method. Limits of detection ranged between 0.04 microgram ml-1 for flavonols and 1.2 micrograms ml-1 for caffeine.

Anticarcinogenic Agents↗

PubMed2000

Regioselective acylation of flavonoid glucoside with aromatic acid by an enzymatic reaction system from cultured cells of Ipomoea batatas.

The regioselective acylation of naturally occurring plant pigments with aromatic acids such as caffeic acid and p-coumaric acid was examined by an enzymatic reaction system from cultured cells of Ipomoea batatas. Isoquercitrin, a flavonoid glucoside, was converted to isoquercitrin 6''-O-caffeate by the enzymatic system. Chrysanthemin, an anthocyanin, was also acylated to the corresponding caffeate ester. This enzymatic method should prove useful for the synthesis of acylated flavonoid glucosides such as isoquercitrin caffeate, whose productivity is low using lipase-catalyzed transesterification.

Journal Article↗

PubMed1997

Saniculoside N from Sanicula europaea L.

Extracts from the aerial parts of Sanicula europaea L. were investigated for their anti-HIV activity, and the 50% ethanolic extract was shown to exhibit the highest activity. A new triterpene saponin glycoside, 21 beta-(angeloyloxy)-3-O-[beta-D-arabinopyranosyl(1-->4)-beta- D-glucopyranosyl (1-->3)-beta-D-glucuronopyranosyl propyl ester]-3 beta,15,16,22 alpha,28 beta-pentahydroxy-delta(12)-oleanene, saniculoside N (1), in addition to the known phenolic acids, rosmarinic acid (2), and caffeic acid (3) were isolated as major components. Rosmarinic acid was established as the principal active substance.

Anti-HIV Agents↗

PubMed2003

New and known iridoid- and phenylethanoid glycosides from Harpagophytum procumbens and their in vitro inhibition of human leukocyte elastase.

Ten compounds, harpagoside (1), 8- p-coumaroylharpagide (2), 8-feruloylharpagide (3), 8-cinnamoylmyoporoside (4), pagoside (5), acteoside (6), isoacteoside (7), 6'- O-acetylacteoside (8), cinnamic acid (9) and caffeic acid (10) were isolated from the storage roots of Harpagophytum procumbens, Pedaliaceae. Compounds 1, 2, 6, 7 and 9 are known for H. procumbens; 3 and 10 were isolated the first time from H. procumbens; compounds 4, 5 and 8 are new natural products. Their structures were elucidated using spectroscopic data (NMR, with NOE, COSY and HMBC experiments, UV, [alpha]). The inhibitory activity of aqueous extracts of the roots of H. procumbens and H. zeyheri as well as the main compounds isolated from H. procumbens was tested on human neutrophile elastase. Although inhibition was comparatively weak a dose-dependence was observed. An IC (50) of 542 microg/mL was determined for the aqueous extract of H. procumbens, but 1012 microg/mL for that of H. zeyheri. 6'- O-Acetylacteoside (8), that is not present in H. zeyheri, inhibited the enzyme with an IC (50) of 47 microg/mL (70 microM), compound 7 with 179 microg/mL (286 microM), 2 with 179 microg/mL (331 microM), 5 with 154 microg/mL (260 microM) and 10, which was also used as reference compound, with an IC (50) of 86 microg/mL (475 microM). The IC (50) values of acteoside, harpagoside, cinnamic acid and stachyose were higher than 300 microg/mL and thus not further determined.

Chromatography, High Pressure Liquid↗

PubMed1996

Four di-O-caffeoyl quinic acid derivatives from propolis. Potent hepatoprotective activity in experimental liver injury models.

The water extract of propolis (PWE) showed a strong hepatoprotective activity against CCl4-toxicity in rats and D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. The PWE also showed a significant hepatoprotective activity against CCl4-induced liver cell injury in cultured rat hepatocytes. The in vitro hepatoprotective activity guided fractionation and chemical analysis led to the isolation of four dicaffeoyl quinic acid derivatives from the PWE. The structure of these isolates was determined to be methyl 3,4-di-O-caffeoyl quinate (1), 3,4-di-O-caffeoyl quinic acid (2), methyl 4,5-di-O-caffeoyl quinate (3), and 3,5-di-O-caffeoyl quinic acid (4) by spectroscopic methods. These compounds were more potent hepatoprotective agents than glycyrrhizin at a concentration of 10 micrograms/ml and 1 was the most potent among the four compounds in the cultured hepatocytes. Quinic acid (5) alone did not show hepatoprotective effects in cultured rat hepatocytes against CCl4-toxicity. On the other hand, chlorogenic acid (6) or caffeic acid alone was found to be less potent than the dicaffeoyl quinic acid derivatives.

Animals↗

PubMed2002

Regulation of lithospermic acid B and shikonin production in Lithospermum erythrorhizon cell suspension cultures.

Cell suspension cultures of Lithospermum erythrorhizon produced a large amount of lithospermic acid B, a caffeic acid tetramer, as well as shikonin derivatives (each ca. 10% of dry wt.) when cultured in shikonin production medium M-9. Various culture factors for increasing the production of lithospermic acid B were investigated. Lithospermic acid B production was inhibited by 2, 4-D or NH4+, whereas it was stimulated by Cu2+. These regulatory patterns were similar to those for the production of shikonin derivatives in these cell cultures, suggestive of close relations and similar metabolic regulation between the production of these compounds. Cultivation under light illumination, however, showed that these metabolisms were independently regulated. In particular, blue light showed a stimulatory effect on lithospermic acid B production, while shikonin production was strongly inhibited, indicative of an effective condition for lithospermic acid B production.

Benzofurans↗

PubMed2002

Constituents of the underground parts of Glehnia littoralis.

From the underground parts of Glehnia littoralis FR. Schmidt ex Miquel (Umbelliferae), 26 compounds, including two new lignan glycosides [giehlinosides A (1) and B (2)], a new neolignan glycoside [glehlinoside C (3)], and a new phenylpropanoid glycoside 14-[beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranosyloxyl-3-methoxypropiophenone (4)1, were obtained and their structures were determined by analysis of their spectral data. The 1,1-diphenyl-2-picrylhydrazyl radical-scavenging assay disclosed quercetin (8), isoquercetin (9), rutin (10), chlorogenic acid (11), and caffeic acid (24) as the major antioxidative constituents in this crude drug.

Apiaceae↗

PubMed1993

Effects of phenolic compounds on bromobenzene-mediated hepatotoxicity in mice.

1. The hepatic protective effects of the phenolic compounds 7,8-dihydroxyflavone, morin, silymarin, caffeic acid and chlorogenic acid on bromobenzene-induced toxicity in mice were studied. 2. Morin, caffeic acid and chlorogenic acid at an oral dose of 200 mg/kg failed to influence hepatotoxicity in vivo, while 7,8-dihydroxyflavone exhibited efficacy and potency higher than those of the reference compound silymarin. 3. 7,8-Dihydroxyflavone, an antioxidant and hepatoprotective agent in vitro, decreased serum glutamate-pyruvate transaminase levels (SGPT) in a dose-related manner, and at 200 mg/kg inhibited bromobenzene-induced glutathione depletion in liver.

Animals↗

PubMed2003

[Phytochemical research of hawthorn species introduced in Lithuania].

UNLABELLED: The natural vegetable resources of Republic of Lithuania can be supplied by imported hawthorn species, subspecies and varieties, not growing naturally in the territory of country, but well growing and able to produce the crude drug with local conditions of the climate. OBJECTIVE: Determinate amounts of phenolic substances (favonoid glycosides and phenolic acids) in the flowers and leaves of collected species of genus Crataegus and Crataegomespilus. MATERIALS AND METHODS: Different examples of crude drug from some Lithuanian regions were extracted with 96% of ethanol and flavonoids were detected spectroscopically and with HPLC (High performance liquid chromatography). RESULTS: In leaves and flowers were found different quantities of common amounts of flavonoids (1.07-2.53%) and different quantities of individual substances: flavonoids (hyperosid, vitexin-O-rhamnosid, rutin, quercitrin, quercetin, vitexin) and phenolic acids (chlorogenic and caffeic acids). CONCLUSION: Flowers and leaves of hawthorn species, introduced in Lithuania, can be used for preparation of crude drugs procurements; the marks of phytochemical compounds of phenotypes from different genetic lines are sufficient grounds for planning of production of crude drug with special phytotherapeutic influences.

Chromatography, High Pressure Liquid↗

PubMed2003

Modulation by phenolic compounds of ABA-induced inhibition of mustard (Brassica juncea L. cv. RLM 198) seed germination.

Exogenous abscisic acid (ABA) inhibited the germination of B. juncea seeds in a concentration dependent manner. As revealed in a time-course study, the ABA-induced inhibition got progressively alleviated with the lapse of time following ABA treatment possibly due to metabolic conversion of applied ABA in the seed tissue. A simultaneous application of certain phenolic compounds namely, p-coumaric-, vanillic-, gallic-, and chlorogenic acid (but not caffeic acid) also caused an alleviation of ABA effect. Of the above two patterns of recovery, the phenolic-dependent alleviation of ABA effect was apparent much earlier (24-48 hr treatment) than the time-dependent one (72 hr). It is likely that phenolics could accelerate ABA metabolism in the seed tissue leading to an early recovery from ABA-induced inhibition.

Abscisic Acid↗

PubMed1989

[Isolation and partial characterization of phenoloxidase from apples (Malus domestica, var. Anna)].

This study pursued the isolation and partial characterization of the enzyme polyphenoloxidase from apple (Malus domestica Anna variety), grown in the Hermosillo Coast (State of Sonora, Mexico). The effects of pH and temperature as well as its specificity towards substrates, and its behavior under conditions of hydrophobic chromatography, were studied. The enzyme was isolated from a residual powder obtained from ripe apples homogenized with cold acetone. The extract thus prepared was used to characterize the enzyme, and it showed an optimum pH of 5.36 and an optimum temperature of 35 degrees C. The substrate specificity proved to decrease from 4-methyl catechol, chlorogenic acid, catechol, and caffeic acid, to 3,4-dihydroxiphenyl alanine (DOPA). The enzyme resulted to be more thermostable (temperature range: 35 degrees C to 60 degrees C) than the rest of oxidases of plant origin. When the extract was eluted under conditions of hydrophobic chromatography separation, it appeared as a single peak resulting in a 300 fold purification. The phenolase activity characteristics found in the present study were similar to those observed in other apples from temperate climates; however, this particular polyphenoloxidase is more thermostable under natural conditions. This explains why apples of the Anna variety, at the high harvesting temperature, show a very fast formation of brown spots even when there is a minor damage. The content of compounds with phenolic group was high (1.16 g/100 g fresh weight). Further increase of the velocity of fruit enzymatic browning was due to this reason.

Chromatography↗

PubMed1980

Purification and characterization of hydroxyindole oxidase from the gills of Mytilus edulis.

An hydroxyindole oxidase has been purified 100-fold from the gill plates of Mytilus edulis. This preparation yields a single band on acrylamide gel electrophoresis and isoelectric focusing. Metal analysis and spectral data show that both heme iron and copper are present in the purified enzyme in a 1:1 molar ratio. Potassium cyanide, sodium azide, various copper chelators, and carbon monoxide inhibit the enzyme-catalyzed reaction. These inhibition studies, as well as the photoreversibility of the CO inhibition, lend support to the conclusion that metal ions function as necessary cofactors for substrate oxidation. The Mytilus gill enzyme oxidizes a variety of substrates, among them biogenic amines. For all substrates tested, 1 dioxygen molecule is consumed/mol of substrate oxidized. When p-coumaric acid is hydroxylated, caffeic acid is formed in quantitative yield. H2O2 has been identified as a second product of the oxidation reaction. The addition of catalase prior to the onset of reaction is inhibitory while H2O2 or ascorbate activate the enzyme. These findings suggest that the hydroxyindole oxidase may be a monooxygenase which does not require reduced pyridine nucleotide for reductive activation.

Animals↗

PubMed1999

Inhibition of peroxynitrite-mediated oxidation of dopamine by flavonoid and phenolic antioxidants and their structural relationships.

The interaction between peroxynitrite and dopamine and the inhibition of this reaction by plant-derived antioxidants have been investigated. Peroxynitrite promoted the oxidation of dopamine to 6-hydroxyindole-5-one as characterised by HPLC and photodiode array spectra, akin to the products of the tyrosinase-dopamine reaction, but no evidence of dopamine nitration was obtained. Although peroxynitrite did not cause nitration of dopamine in vitro, the catecholamine is capable of inhibiting the formation of 3-nitrotyrosine from peroxynitrite-mediated nitration of tyrosine. The plant-derived phenolic compounds, caffeic acid and catechin, inhibited peroxynitrite-mediated oxidation of dopamine. This effect is attributed to the ability of catechol-containing antioxidants to reduce peroxynitrite through electron donation, resulting in their oxidation to the corresponding o-quinones. The antioxidant effect of caffeic acid and catechin was comparable to that of the endogenous antioxidant, glutathione. In contrast, the structurally related monohydroxylated hydroxycinnamates, p-coumaric acid and ferulic acid, which inhibit tyrosine nitration through a mechanism of competitive nitration, did not inhibit peroxynitrite-induced dopamine oxidation. The findings of the present study suggest that certain plant-derived phenolics can inhibit dopamine oxidation.

Antioxidants↗

PubMed2001

Identification and antioxidant activity of novel chlorogenic acid derivatives from bamboo (Phyllostachys edulis).

One known and two novel antioxidant compounds have been isolated from bamboo (Phyllostachys edulis). The butanol-soluble extract of the bamboo leaves was found to have a significant antioxidant activity, as measured by scavenging the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and the superoxide anion radical (O(2)(-)) in the xanthine/xanthine oxidase assay system. Antioxidant activity-directed fractionation of the extract led to the isolation and characterization of three structural isomeric chlorogenic acid derivatives: 3-O-(3'-methylcaffeoyl)quinic acid (1), 5-O-caffeoyl-4-methylquinic acid (2), and 3-O-caffeoyl-1-methylquinic acid (3). Compounds 2 and 3 were isolated and characterized for the first time from the natural products. In the DPPH scavenging assay as well as in the iron-induced rat microsomal lipid peroxidation system, compounds 2 (IC(50) = 8.8 and 19.2 microM) and 3 (IC(50) = 6.9 and 14.6 microM) showed approximately 2-4 times higher antioxidant activity than did chlorogenic acid (IC(50) = 12.3 and 28.3 microM) and other related hydroxycinnamates such as caffeic acid (IC(50) =13.7 and 25.5 microM) and ferulic acid (IC(50) = 36.5 and 56.9 microM). Among the three compounds, compound 1 yielded the weakest antioxidant activity, and the DPPH scavenging and lipid peroxidation inhibitory activity (IC(50) = 16.0 and 29.8 microM) was lower than those of chlorogenic and caffeic acids. All three compounds exhibited both superoxide scavenging activities and inhibitory effects on xanthine oxidase. Their superoxide anion (O(2)(-)) scavenging activities (IC(50) = 1, 4.3 microM; 2, 2.8 microM; and 3, 1.2 microM) were markedly stronger than those of ascorbic acid (IC(50) = 56.0 microM), alpha-tocopherol (IC(50) > 100 microM), and other test compounds, although their inhibition effects on xanthine oxidase may contribute to the potent scavenging activity. alpha-Tocopherol exerted a significant inhibitory effect (65.5% of the control) on superoxide generation in 12-O-tetradecanoylphorbol-13-acetate-induced human promyelocytic leukemia HL-60 cells, and compound 3 showed moderate activity (36.0%). On the other hand, other compounds including 1, 2, chlorogenic acid, and other antioxidants were weakly active (24.8-10.1%) in the suppression of superoxide generation.

Animals↗

PubMed2003

[Effect of phenolic compounds of virgin olive oil on LDL oxidation resistance].

BACKGROUND AND OBJECTIVE: Several epidemiological and experimental studies have associated the intake of antioxidants, which are abundant in the Mediterranean diet, with a low incidence of cardiovascular disease. One possible mechanism of this action is the oxidative protection in low density lipoproteins (LDL). The aim of our study was to compare the antioxidative activity of diverse phenolic compounds present in virgin olive oil on these lipoproteins. SUBJECTS AND METHOD: LDL was isolated from blood plasma of healthy volunteers by sequential ultracentrifugation. This was followed by oxidation with CuC12 in the presence of different concentrations of phenolic compounds and virgin olive oil extract. Production of conjugated dienes was determined by the continuous monitoring of increased absorbency at 234 nm as an indicator of LDL oxidation. RESULTS: Virgin olive oil extract prolonged the latency phase and significantly lowered the progression rate (p < 0.05) at low concentrations (2 g/ml). This antioxidative effect was also observed with low concentrations (2 M) of caffeic acid and oleuropein (p < 0.05). However, it was necessary to increase the concentration of flavone up to 50 times to observe a similar effect (p < 0.05). CONCLUSION: Both virgin olive oil extract enriched in phenolic compounds and phenolic compounds present in olive oil (caffeic acid and oleuropein) are potent antioxidants at very low concentrations. Thus, the beneficial effects of a Mediterranean diet may be partly due to the protective action of these compounds.

Antioxidants↗

PubMed2001

Effects of fukinolic acid and cimicifugic acids from Cimicifuga species on collagenolytic activity.

The inhibitory collagenolytic activity (47-64% inhibition in 0.22-0.24 microM) of fukinolic acid and cimicifugic acids A, B, and C, which are esters of fukiic acid (3',4'-dihydroxybenzyl tartaric acid) was more potent than that (20-37% inhibition in 0.23-0.24 microM) of cimicifugic acids D, E, F, which are esters of pscidic acid (4'-hydroxybenzyl tartaric acid). Since fukiic acid showed weaker inhibition, and caffeic acid, ferulic acid, isoferulic acid, and p-coumaric acid showed far weaker activities, the entire structures of fukinolic acid and cimicifugic acids A, B, and C proved to be responsible for the inhibitory activities. Trypsin and pronase E hydrolyzed collagen nonselectively alone or in addition to collagenase. These collagenolytic activities were also inhibited by fukinolic acid. These results show that fukinolic acid may inhibit either the collagenolytic activities specific to collagenase or nonspecific to other emzymes. The present studies suggest the potential effect of fukinolic acid and cimicifugic acids of Cimicifuga rhizomes in preventing collagen degradation by collagenases or collagenolytic enzymes under pathological conditions, wound healing, or inflammation.

Caffeic Acids↗

PubMed2005

Screening of novel nuclear receptor agonists by a convenient reporter gene assay system using green fluorescent protein derivatives.

Nuclear receptors represent a very good family of protein targets for the prevention and treatment of diverse diseases. In this study, we screened natural compounds and their derivatives, and discovered ligands for the retinoic acid receptors (RARs) and the farnesoid X receptor (FXR). In the reporter assay systems of nuclear receptors presented here, two fluorescent proteins, enhanced yellow fluorescent protein (EYFP) and enhanced cyan fluorescent protein (ECFP), were used for detection of a ligand-based induction and as an internal control, respectively. By optimizing the conditions (e.g., of hormone response elements and promoter genes for reporter plasmids), we established a battery of assay systems for ligands of RARs, retinoid X receptor (RXR) and FXR. The screening using the reporter assay system can be carried out without the addition of co-factors or substrates. As a result of screening of more than 140 compounds, several compounds were detected which activate RARs and/or FXR. Caffeic acid phenylethyl ester (CAPE), known as a component of propolis from honeybee hives, and other derivatives of caffeic acid up-regulated the expression of reporter gene for RARs. Grifolin and ginkgolic acids, which are non-steroidal skeleton compounds purified from mushroom or ginkgo leaves, up-regulated the expression of the reporter gene for FXR.

Animals↗

PubMed2003

Antitumor activity of wheats with high orthophenolic content.

The purpose of the present study is to develop in vitro assays for rapid screening of a large number of food samples that contain components that prevent tumor formation in vivo and to identify the components that contribute to this antitumor effect. Wheat samples representing numerous strains and cultivars were screened for their in vitro ability to kill a human colon cancer cell, CaCo2, in culture by trypan blue dye exclusion assay. Wheat samples were assayed for orthophenolic acid content by use of a colorimetric assay using a bathochromatic shift at 350 nm. Blood levels of specific orthophenols were determined by high-performance liquid chromatography/mass spectrometry. Wheat samples, which contained low, mid-, and high in vitro protective ability, were used to formulate balanced diets fed to Min mice. Wheat samples with high ability to kill CaCo2 cells in culture had high levels of orthophenolic acids and produced elevated blood caffeic acid levels when used in diets. These factors correlated positively with their ability to prevent tumor formation in Min mice. When fiber content was equal in diets the content of orthophenolic acids in wheats predicted the antitumor activity in vivo.

Animals↗