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PubMedDate not supplied

Variability in the composition of anti-oxidant compounds in Echinacea species by HPLC.

A fast and reliable HPLC method for the determination of caffeic acid derivatives (caftaric acid, chlorogenic acid, caffeic acid, cynarin, echinacoside and cichoric acid) in various species of the genus Echinacea has been developed. Extraction of root samples by magnetic stirring with 80% methanol aqueous solution at room temperature allowed the complete recovery of all compounds of interest. Root extracts were analysed on a reversed-phase column with gradient elution and photodiode array detection. Caffeic acid derivatives showed differential qualitative and quantitative distributions in Echinacea species. The total amount of phenolic compounds ranged from 33.95 to 0.32 mg/g. The highest contents of caffeic acid derivatives were found in E. paradoxa var. paradoxa, E. paradoxa var. neglecta and E. purpurea, followed by E. angustifolia var. angustifolia, E. simulata, E. pallida and E. laevigata, whilst E. tennesseensis, E. sanguinea and E. atrorubens had low amounts of phenolic compounds. The radical scavenging activities of methanolic extracts of roots of Echinacea species was evaluated in vitro using the DPPH* radical scavenging method. The EC50 values of the samples ranged from 122 to 1223 microg/mL. The radical scavenging activities of the root extracts were correlated with the content of phenolic compounds, with a correlation coefficient (r2) of 0.923.

Antioxidants↗
PubMedDate not supplied

Effect of cysteine, N-acetyl-L-cysteine and glutathione on cytotoxic activity of antioxidants.

The effect of twenty amino acids on the radical intensity of four antioxidants (sodium L-ascorbate, sodium 5,6-benzylidene-L-ascorbate, gallic acid, caffeic acid) was investigated, using ESR spectroscopy. Methionine and methional did not significantly affect the radical intensity of these antioxidants. Methionine sulfoxide slightly enhanced the radical intensity of sodium ascorbate and sodium 5,6-benzylidene-L-ascorbate, but did not that of gallic acid and caffeic acid. Cysteine, N-acetyl cysteine and glutathione significantly reduced the radical intensity and cytotoxic activity of these antioxidants except for sodium 5,6-benzylidene-L-ascorbate. The other amino acids were inactive. The present study further supports that these antioxidants induce cytotoxicity via their pro-oxidant action.

Acetylcysteine↗
PubMed2003

Analysis of propolis from the continental and Adriatic regions of Croatia.

Thin-layer chromatography of ethanolic extract of propolis (EEP) from the continental and Adriatic regions of Croatia showed that 72.2% of propolis samples contain galangin, 88.8% of samples contain kaempferol, naringenin and apigenin and 66.6% of samples contain caffeic acid. Caffeic acid, pinocembrin, galangin, chrysin and naringenin were analyzed by HPLC. In all samples, pinocembrin was the dominant flavonoid. In samples from the Adriatic region, concentration of pinocembrin ranged from 0.03 to 6.14% (x = 2.87%) and in the continental region samples from 0 to 4.74% (x = 2.84%). Chrysin was found in all propolis samples in a concentration ranging from 0.22 to 5.32% (x = 1.86%) in the continental region samples and from 0.03 to 3.64% (x = 1.96%) in samples from the Adriatic region. Chrysin was followed by naringenin, ranging from 0 to 1.14% (x = 0.42%) in samples from the Adriatic region and from 0.22 to 2.41% (x = 0.60%) in the continental region samples. Concentration of caffeic acid ranged from 0 to 10.11% (x = 2.69%) in the Adriatic region samples and from 0.27 to 2.67% (x = 1.37%) in samples from the continental region of Croatia. Results of HPLC analyses suggest that propolis samples collected from various parts of Croatia do not differ markedly in contents of chrysin, pinocembrin, naringenin and galangin but differ in the concentration of caffeic acid. All EEPs significantly inhibited the growth of Bacillus subtilis in comparison with the control (80% ethanol) (p < 0.05), showing inhibition zones of 16 +/- 2 mm for samples from the continental region, and of 18 +/- 3 mm for samples from the Adriatic region. There was no significant difference in antimicrobial activity of EEPs from the continental and Adriatic regions of Croatia, suggesting that bactericidal activity depends on synergism of all phenolic compounds.

Animals↗
PubMed2005

Antioxidant activities of phenolic acids on ultraviolet radiation-induced erythrocyte and low density lipoprotein oxidation.

The exposure of mammalian cells to UV light induces various deleterious responses. Some of the major harmful effects are DNA damage, cell membrane peroxidation, systemic immune suppression, and aging acceleration. Reactive oxygen species and free radicals are believed to be largely responsible for some of the deleterious effects of UV upon cells. Typical administration of antioxidants has recently proved to represent a successful strategy for protecting the cells against UV-mediated oxidative damage. The objective of this study was to investigate the inhibitory effect of phenolic acids (caffeic acid, ferulic acid, gallic acid, and protocatechuic acid) on oxidative damage in human erythrocytes and low-density lipoprotein (LDL) induced by UVB radiation. The results revealed that the thiobarbituric acids reactive substances induced by UVB were decreased from 2.78 to 0.12-0.89 nmol MDA/mg protein in erythrocyte ghost and from 0.72 to 0.14-0.43 nmol MDA/mg protein in LDL by the addition of phenolic acids (100 muM). Caffeic acid, ferulic acid, and gallic acid exhibited over 85 and 60% inhibitory effect toward UVB-induced oxidation in erythrocytes and LDL, respectively. Phenolic acids, especially gallic acid, could maintain the normal glutathione levels and glutathione peroxidase activity in hemolysate from erythrocytes that were exposed to UVB radiation in comparison with untreated control. The results indicate that the antioxidant activities of caffeic acid and ferulic acid play a potential role in protection against UVB oxidative damage to human erythrocytes and LDL.

Antioxidants↗
PubMed1999

Inhibitory mechanism of sinapinic acid against peroxynitrite-mediated tyrosine nitration of protein in vitro.

The peroxynitrite-scavenging ability of some phenolic antioxidants, p-coumaric acid, caffeic acid and sinapinic acid, was examined and compared with ascorbic acid and tocopherol using 3-nitrotyrosine formation as a marker. Among these, caffeic acid and sinapinic acid strongly inhibited the formation of 3-nitrotyrosine in protein. The treatment of protein with peroxynitrite in the presence of sinapinic acid, but not caffeic acid, produced a novel product determined by reversed-phase high performance liquid chromatography (HPLC). The product formed was purified and then identified as a mono-lactone type dimer (ML) of sinapinic acid by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC-MS). This ML was converted from a di-lactone type dimer, obtained from sinapinic acid with peroxidase/hydrogen peroxide, in neutral buffer. In this report, we have proposed that the ML of sinapinic acid is generated via one-electron oxidation by peroxynitrite treatment.

Chromatography, High Pressure Liquid↗
PubMed1976

[In vitro studies of the antiviral activity of enzymatically oxidized o-diphenolic compounds against herpes simplex virus type 1 and 2 (author's transl)].

Oxidation of the o-diphenolic compounds, catechol, protocatechuic acid, caffeic acid, and chlorogenic acid by o-diphenol oxidase (EC 1.10.3.1) resulted in compounds with antiviral activity against herpes simplex virus types 1 and 2. In the system HSV-1/rabbit kidney primary cells, a 90 per cent plaque reduction was obtained by the oxidation product from 1 mug caffeic acid, 9 mug catechol, 13 mug chlorogenic acid, or 20 mug protocatechuic acid (per ml), respectively. In comparision to the basic compounds or those oxidized in the presence of bovine serum albumin, the inhibitory effect of oxidized o-diphenolic compounds free from albumin was higher. From the basic o-diphenolic compounds, only catechol and caffeic acid showed remarkable antiviral activities in the system investigated. Although there have not experiments on the mechanism of action yet been the compounds are supposed to act during the earliest phases of the HSV-multiplication, because o-diphenolic compounds had been found to be present in the virus-cell system only 90 minutes after infection. In this respect the substances were similar to those of humic acids which also inhibit the adsorption phase of herpes simplex virus. There were no essential differences between herpes simplex virus type 1 and type 2 in respect of their sensitivity to enzymatically oxidized o-diphenolic compounds.

Animals↗
PubMed1991

Effects of phenolcarboxylic acids on superoxide anion and lipid peroxidation induced by superoxide anion.

The effects of phenolcarboxylic acids, caffeic acid, p-coumaric acid, and ferulic acid on the generation of superoxide anion and the production of lipid peroxide induced by superoxide anion were studied. Only ferulic acid anion among the phenolcarboxylic acids scavenged superoxide. Caffeic acid and ferulic acid inhibited lipid peroxidation induced by superoxide anion. These effects were comparable to those of superoxide dismutase or DL-alpha-tocopherol.

Caffeic Acids↗
PubMed2006

Uptake and metabolism of hydroxycinnamic acids (chlorogenic, caffeic, and ferulic acids) by HepG2 cells as a model of the human liver.

Hydroxycinnamic acids are antioxidant polyphenols common in the human diet, although their potential health benefits depend on their bioavailability. To study the hepatic uptake and metabolism, human hepatoma HepG2 cells were incubated for 2 and 18 h with caffeic, ferulic, and chlorogenic acids. Moderate uptake of caffeic and ferulic acids was observed versus a low absorption of chlorogenic acid, where esterification of the caffeic acid moiety markedly reduced its absorption. Methylation was the preferential pathway for caffeic acid metabolism, along with glucuronidation and sulfation, while ferulic acid generated glucuronides as the only metabolites. Ferulic acid appeared to be more slowly taken up and metabolized by HepG2 cells than caffeic acid, with 73% and 64% of the free, nonmetabolized molecules detected in the culture medium after 18 h, respectively. In conclusion, hydroxycinnamic acids can be metabolized by the liver as suggested by the results obtained using HepG2 cells as a hepatic model system.

Absorption↗
PubMed2004

Determination of active ingredients in Huangdan Yinchen Keli by CZE with amperometric detection.

A simple, reliable and reproducible method, based on capillary zone electrophoresis with amperometric detection (CZE-AD), has been developed for simultaneous determination of five active ingredients in complicated traditional Chinese medicines including chlorogenic acid, caffeic acid, aloe-emodin, emodin and rhein. A carbon-disk electrode was used as working electrode. The optimal conditions of CZE detection were 30 mM borate solution (pH 9.5) as running buffer, 18 kV as separation voltage and 1.00 V (versus Ag/AgCl) as detection potential. There was excellent linearity between current response and analyte concentration over two orders of magnitude, while the limits of detection were 1.1 x 10(-7), 3.0 x 10(-7), 1.5 x 10(-7), 2.9 x 10(-7), 1.4 x 10(-6) mol/l for aloe-emodin, emodin, rhein, chlorogenic acid and caffeic acid, respectively (S/N = 3). The utility of this method was demonstrated by monitoring a kind of complicated Chinese medicine named Huangdan Yinchen Keli. Two samples manufactured by different companies were monitored with satisfactory results.

Drugs, Chinese Herbal↗
PubMed2006

[Simultaneous determination of four compounds in Sanjing Shuanghuanglian Oral Liquid by high performance liquid chromatography-diode array detection-electrochemical detection].

Chlorogenic acid, caffeic acid, baicalin and luteolin in Sanjing Shuanghuanglian Oral Liquid were simultaneously detected and identified using a high performance liquid chromatography coupled with diode array detection and electrochemical detection (HPLC-DAD-ECD). The separation was performed on a Zorbax SB-C18 column (150 mm x 4.6 mm i. d., 5.0 microm). The mobile phase consisted of (A) methanol and (B) methanol-water-acetic acid (50: 50: 1, v/v/v) using a linear gradient elution of 2%A-3%A at 0-3 min, 3%A-25%A at 3-15 min, 25%A-80%A at 15-20 min. The flow rate was 0.8 mL/min. The DAD detection was used at 275 nm. The ECD detection was done at 0.7 V. The column thermostat set at 30 degrees C. The limits of detection of the 4 compounds were 1 mg/L for chlorogenic acid, 0.2 mg/L for caffeic acid, 9 mg/L for baicalin, 7 mg/L for luteolin. The average recoveries were between 96.6%-99.6% with relative standard deviations (RSDs) of 2.5%-4.1%. The method is simple, rapid, reproducible and accurate. It can be used for the routine analysis of the four compounds in Shuanghuanglian Oral Liquid.

Caffeic Acids↗
PubMed2002

Determination of free and total phenolic acids in plant-derived foods by HPLC with diode-array detection.

A high-performance liquid chromatographic (HPLC) method with diode-array detection (DAD) was used to identify and quantify free and total phenolic acids (m-hydroxybenzoic acid, p-hydroxybenzoic acid, protocatechuic acid, gallic acid, vanillic acid, syringic acid, o-coumaric acid, m-coumaric acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid, chlorogenic acid, and ellagic acid) in plant foods. Free phenolic acids were extracted with a mixture of methanol and 10% acetic acid. Bound phenolic acids were liberated using first alkaline and then acid hydrolysis followed by extraction with diethyl ether/ethyl acetate (1:1). All fractions were quantified separately by HPLC. After HPLC quantification, results of alkali and acid hydrolysates were calculated to represent total phenolic acids. Ellagic acid was quantified separately after long (20 h) acid hydrolysis. The methods developed were effective for the determination of phenolic acids in plant foods. DAD response was linear for all phenolic acids within the ranges evaluated, with correlation coefficients exceeding 0.999. Coefficients of variation for 4-8 sample replicates were consistently below 10%. Recovery tests of phenolic acids were performed for every hydrolysis condition using several samples. Recoveries were generally good (mean >90%) with the exceptions of gallic acid and, in some cases, caffeic acid samples.

Caffeic Acids↗
PubMed2000

Characterization of potentially chemopreventive phenols in extracts of brown rice that inhibit the growth of human breast and colon cancer cells.

Rice is a staple diet in Asia, where the incidence of breast and colon cancer is markedly below that in the Western world. We investigated potential colon and breast tumor-suppressive properties of rice, testing the hypothesis that rice contains phenols that interfere with the proliferation or colony-forming ability of breast or colon cells. Brown rice, its white milled counterpart, and bran from brown rice were boiled and extracted with ethyl acetate. The extracts were analyzed by high pressure liquid chromatography-mass spectrometry. Eight phenols, protocatechuic acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid, vanillic acid, methoxycinnamic acid, and tricin, were identified in the extracts of bran and intact brown rice. These extracts were separated into nine fractions by column chromatography. The effect of bran extract and its fractions at 100 microg/ml on cell viability and colony-forming ability of human-derived breast and colon cell lines was assessed. Bran extract decreased numbers of viable MDA MB 468 and HBL 100 breast cells and colon-derived SW 480 and human colonic epithelial cells as judged by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4 -sulfophenyl)-2H-tetrazolium assay. It also reduced colony formation of SW 480 colon and MDA MB 468 breast cells. Of the eight phenols identified in the brown rice bran, when applied at 50 microM, caffeic acid decreased numbers of all cell types except HBL 100. Tricin, ferulic acid, and methoxycinnamic acid interfered with cell viability in one or more cell lines. Tricin (50 microM) and the other phenols (200 microM) inhibited colony formation of SW 480 cells. Clonogenicity of MDA MB 468 cells was inhibited by caffeic acid, ferulic acid, and tricin (50 microM). Tricin was the most potent anticlonogenic of the compounds with IC50s of 16 microM in the SW 480 colon cells and 0.6 microM in the MDA MB 468 breast cells. The results suggest that: (a) brown rice and bran contain compounds with putative cancer chemopreventive properties; (b) certain phenols contained in brown rice bran, e.g., tricin, may be associated with this activity; and (c) these phenols are present at much lower levels in white than in brown rice. Thus, the consumption of rice bran or brown rice instead of milled white rice may be advantageous with respect to cancer prevention.

Breast Neoplasms↗
PubMed2002

Cytotoxic ent-kaurane diterpenoids from Isodon sculponeata.

Four new ent-kaurane diterpenoids, sculponeatins F-I (1-4), together with six known compounds, sculponeatin E (5), epi-nodosin (6), epi-nodosinol (7), enmein (8), and macrocalyxoformins A and B (9 and 10), were isolated from the leaves of Isodon sculponeata. Also obtained were ursolic acid, 2alpha,3beta-dihydroxy-urs-12-en-28-oic acid, 2alpha,3beta,19alpha-trihydroxy-urs-12-en-28-oic acid, beta-sitosterol, daucosterol, quercetin, pedalitin, rosmarinic acid, caffeic acid and ethyl caffeic acid. Their structures were determined by spectral methods (1D-, 2D-NMR and MS). Some diterpenoids were tested for their cytotoxicity to inhibit three kinds of human tumor cells K562, A549 and T24. Compounds 3, 4, 6, 8, and 10 showed significant inhibitory effect toward K562 with IC(50) values ranging from 3.2 microg/ml to 8.2 microg/ml, while 3 and 6 exhibited potent antitumor activity against T24, but none exhibited cytotoxicity toward the cells of A549.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Antioxidant activity of phenolic compounds isolated from Mesona procumbens Hemsl.

The antioxidant activity of phenolic compounds isolated from Mesona procumbens Hemsl. (Hsian-tsao) was investigated. Hsian-tsao was extracted with various solvents, and the results showed that the fraction treated with acidic ethyl acetate (pH 2) possessed large amounts of phenolic compounds and a strong antioxidant activity on peroxidation of linoleic acid. The antioxidant activity (inhibition of peroxidation, IP%) of the acidic ethyl acetate of Hsian-tsao extract at 50 microg/mL (98.9%) was stronger than those of 50 microg/mL alpha-tocopherol (78%) and BHA at 10 microg/mL (90%). When fractionated with Amberlite XAD-7 gel chromatography, the acidic ethyl acetate fraction of Hsian-tsao extract was separated into four subfractions (A-D). Subfraction B, with high yield and strong antioxidant activity, was further isolated and purified and then identified as containing protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, and syringic acid by means of UV, EI-MS, and (1)H and (13)C NMR. The antioxidant capability of isolated compounds was also determined using the thiocyanate system and the erythrocyte ghost system. The results indicate that the phenolic acids could be important antioxidant components in Hsian-tsao, among which caffeic acid with the highest antioxidant activity and the greatest content is most important.

Acetates↗
PubMed2006

In vivo anti-inflammatory and anti-nociceptive activities of Cheilanthes farinosa.

In Ethiopia inflammatory skin diseases are among the most common health problems treated with traditional remedies which mainly comprise medicinal plants. In the present work, the anti-inflammatory and anti-nociceptive activities of Cheilanthes farinosa (Forsk.) Kaulf (Adianthaceae), a fern used in many parts of Ethiopia to treat inflammatory skin disorders, were studied using in vivo models of inflammation and pain. The results of the study showed that the fronds Cheilanthes farinosa possess strong anti-inflammatory and anti-nociceptive properties. It was further demonstrated that the active ingredients of the fern reside mainly in the methanol fraction from which three compounds viz. the flavonol glycoside rutin, and the natural cinnamic acids, caffeic acid and its quinic acid derivative chlorogenic acid have been isolated. The methanol extract was also shown to potentiate the anti-inflammatory activity of acetyl salicylic acid. At the tested concentrations, the methanol extract displayed a better anti-nociceptive activity than that of ASA in both the early and late phases of formalin induced nociception in mice. However, the activity of the extract was more pronounced in the late phase, which is commonly associated with inflammatory pain. Evaluation of the pharmacological properties of the compounds isolated from the active fractions pointed out that chlorogenic acid possesses strong anti-inflammatory and anti-nociceptive activities while caffeic acid and rutin were inactive. Moreover, on molar basis chlorogenic acid was proved to be superior in its anti-inflammatory action to acetyl salicylic acid. It was therefore concluded that chlorogenic acid contributes, in full or in part, to the anti-inflammatory and anti-nociceptive activities of Cheilanthes farinosa. Both the methanolic extract and pure chlorogenic acid failed to display anti-nociceptive activity when tested by the tail-flick test indicating that the plant is not a centrally acting analgesic but instead exerts its analgesic activity by way of its antinflammtory action.

Administration, Oral↗
PubMed2005

Effects of some naturally occurring iron ion chelators on in vitro superoxide radical formation.

The effects of some naturally occurring iron ion chelators and their derivatives on the electron transfer from ferrous ions to oxygen molecules were examined by measuring oxygen consumption rates. Of the compounds examined, quinolinic acid, fusaric acid, and 2-pyridinecarboxylic acid repressed the oxygen consumption, whereas chlorogenic acid, caffeic acid, gallic acid, catechol, L-beta-(3,4-dihydroxyphenyl)alanine, and xanthurenic acid accelerated it. Theoretical calculations showed that the energies of the highest occupied molecular orbitals (HOMOs) of [Fe(II)(ligand)3]- complexes were relatively high when the ligands were caffeic acid and its derivatives such as catechol, gallic acid, and L-beta-(3,4-dihydroxyphenyl)alanine. On the other hand, the energies of the HOMOs of [Fe(II)(ligand)3]- complexes were relatively low when the ligands were quinolinic acid and its derivatives such as 2-pyridinecarboxylic acid and fusaric acid. The energies of the HOMOs appear to be closely related with acceleration or repression of the oxygen consumption; that is to say, when the energy of the HOMO is high, the oxygen consumption is accelerated, and vice versa.

Antioxidants↗
PubMed1988

Mutagenic activity of some coffee flavor ingredients.

The mutagenicity of 4 coffee flavor ingredients (chlorogenic acid, caffeic acid, pyrazine, and trigonelline) was evaluated in the Salmonella plate incorporation assay and mouse lymphoma L5178Y TK +/- assay. Two of the compounds, pyrazine and trigonelline, were negative in both assays. The other two compounds, caffeic acid and chlorogenic acid, were positive in the mouse lymphoma assay but negative in the Salmonella assay.

Alkaloids↗
PubMed2001

Effect of natural phenolic acids on DNA oxidation in vitro.

We examined the antioxidant activity of the following natural phenolic compounds present in food: 3-OH-benzoic acid (3-OH-BA); 4-OH-benzoic acid (4-OH-BA); 2,3-dihydroxybenzoic acid (2,3-diOH-BA); 3,4-dihydroxybenzoic acid (3,4-diOH-BA or protocatechuic acid); ferulic acid; caffeic acid; and 2-coumaric, 3-coumaric and 4-coumaric acids. We measured the inhibitory effect of these compounds on iron-dependent oxidative DNA damage in vitro [incubating herring sperm DNA with Fe(III)/GSH] or using cumene hydroperoxide (CumOOH) as a free-radical generating system; we also studied the interaction of these phenols with Fe(II) or Fe(III) spectrophotometrically. Among the tested compounds, 2,3-diOH-BA, 3,4-diOH-BA and caffeic acid interacted with Fe(II) and showed a potent inhibitory effect on iron-induced oxidative DNA damage. CumOOH-induced DNA oxidation was not modified by these compounds. On the contrary, 2-coumaric, 3-coumaric and 4-coumaric acids did not interact with iron but protected against oxidative DNA damage induced by Fe(III)/GSH and by CumOOH, indicating a direct free-radical scavenging activity of these compounds in both systems. The IC(50)+/-S.E.M. of the three coumaric acids against CumOOH-induced DNA oxidation was 44.2+/-2.0, 54.7+/-2.0 and 33.1+/-1.0 microM, respectively. On the contrary, 3-OH-BA and 4-OH-BA did not have scavenging activity and 3-OH-BA actually enhanced oxidative DNA damage. In conclusion, some natural phenolic acids, commonly present in food, have interesting protective activity against DNA oxidation in vitro and deserve further consideration as effective antioxidants in vivo.

Animals↗