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PubMed1992

Epidermal growth factor enhances a microsomal 12-lipoxygenase activity in A431 cells.

12-Hydroxyeicosatetraenoic acid (12-HETE) is formed from arachidonic acid either by 12-lipoxygenase or by a cytochrome P450 monooxygenase. 12-Lipoxygenase is generally localized in the soluble cytosolic fraction, and the cytochrome P450 monooxygenase is a microsomal enzyme. In this study, 12-HETE biosynthesis and the regulation of 12-HETE biosynthesis by epidermal growth factor (EGF) in A431 cells were investigated. 12-HETE was biosynthesized from arachidonic acid by the microsomal fraction of A431 cells, but not by the cytosolic fraction. The formation of 12-HETE was inhibited by 5,8,11,14-eicosatetraynoic acid, nordihydroguaiaretic acid, and caffeic acid. Nordihydroguaiaretic acid at 10(-4) M and 5,8,11,14-eicosatetraynoic acid at 10(-5) M almost completely inhibited its formation. However, the formation of 12-HETE was not affected by the presence of an NADPH-generating system, carbon monoxide, or SKF 525A. The biosynthetic 12-HETE was analyzed by chiral stationary phase high performance liquid chromatography and was highly enriched in (12S)-HETE. We therefore concluded that the enzyme responsible for the formation of (12S)-HETE in the microsomes of A431 cells is a 12-lipoxygenase. The microsomal 12-lipoxygenase of A431 cells belongs to the "leukocyte-type" enzyme as determined by substrate specificity and enzyme kinetics studies. The microsomal 12-lipoxygenase oxygenated linoleic acid much faster than the cytosolic platelet 12-lipoxygenase and is a "self-catalyzed inactivation" enzyme. Treatment of cells with 50 ng/ml EGF significantly induced microsomal 12-lipoxygenase activity. The lag period for the expression of the stimulatory effect of EGF on 12-lipoxygenase activity was approximately 10 h. The stimulatory effect of EGF on 12-lipoxygenase activity was completely blocked by treatment with 35 microM cycloheximide, indicating a requirement for de novo protein biosynthesis. Furthermore, the presence of the endogenous inhibitor of 12-lipoxygenase (which masked (12S)-HETE biosynthesis in intact cells) was identified in the cytosolic fraction of A431 cells. The putative inhibitor was enzyme-selective. It inhibited the leukocyte-type 12-lipoxygenase, but not the "platelet-type" enzyme.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed2000

Substrate preferences of caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferases in developing stems of alfalfa (Medicago sativa L.).

Caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase (COMT, EC 1.2.1.68) catalyzes at least two reactions in lignin biosynthesis. Of its two supposed substrates in the lignin pathway, COMT from most sources methylates 5-hydroxyferulic acid (5HFA) with two to three times higher activity than caffeic acid (CafA). The ratio of activity for 5HFA compared with CafA increases with the developmental age of alfalfa (Medicago sativa L.) stem internodes, from approximately 1:1 in young (third and fourth) internodes to 2:1 in mature (seventh and eighth) internodes. This observation, together with immunoblot analysis using antiserum raised against recombinant alfalfa COMT, suggests the presence of a different form of COMT, having preference for CafA compared with 5HFA, in young internodes. This apparently new O-methyltransferase (COMT II) was separated from the previously characterized COMT (COMT I) by anion exchange and hydrophobic interaction chromatography. COMT I, but not COMT II, was found in mature internodes. COMT II was not recognized by anti-(COMT I) serum. Furthermore, in addition to substrate preference, COMT II differed from COMT I in native relative molecular mass, pH optimum, and its very low K(m) for CafA. The possible physiological role of COMT II is discussed.

Blotting, Western↗
PubMed1996

The effect of propolis and its components on eicosanoid production during the inflammatory response.

To investigate the possible mechanism of the therapeutic action of propolis, we studied: (a) the effect of propolis, its components, caffeic acid phenethyl ester (CAPE), caffeic acid (CA), quercetin and naringenin, as well as the synthetic compounds indomethacin (IM) and nordihydroguaiaretic acid (NDGA), and a novel lipoxygenase inhibitor N,N'-dicyclohexyl-O-(3,4-dihydroxycinnamoyl)isourea (DCHCU) on eicosanoid production by mouse peritoneal macrophages in vitro; (b) the effect of IM, NDGA, CA, CAPE, DCHCU and propolis on eicosanoid production during acute inflammation in vivo; and (c) the ex vivo and in vivo effect of dietary propolis on arachidonic acid metabolism. The ethanol extract of propolis suppressed prostaglandin and leukotriene generation by murine peritoneal macrophages in vitro and during zymosan-induced acute peritoneal inflammation in vivo. Dietary propolis significantly suppressed the lipoxygenase pathway of arachidonic acid metabolism during inflammation in vivo. CAPE was the most potent modulator of the arachidonic acid cascade among the propolis components examined.

Animals↗
PubMed1976

Caffeic acid-containing medium for identification of Cryptococcus neoformans.

A new growth medium containing caffeic acid and ferric citrate is described. The pigment produced on this medium is specific for the identification of Cryptococcus neoformans and differentiates it from other cryptococci. The medium is more easily compounded and requires less time for pigment formation than the conventional Guizotia extract media. The medium is stable in the dry form as well as in the prepared form.

Caffeic Acids↗
PubMed2002

Potentiation of vasoconstrictor response and inhibition of endothelium-dependent vasorelaxation by gallic acid in rat aorta.

In the isolated rat thoracic aorta, gallic acid potentiated the vasoconstrictor response to phenylephrine. The potentiation produced by gallic acid was absent in endothelium-denuded arteries. The potentiation was abolished by N(G)-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthesis, and slightly attenuated by an addition of L-arginine, while indomethacin or BQ610 had no effect. The potentiation of response to phenylephrine was not found for structural modifications of gallic acid, except for caffeic acid. Gallic acid also inhibited vasorelaxation induced by acetylcholine, sodium nitroprusside or prostacyclin, especially that by acetylcholine. The effect on vasorelaxation induced by acetylcholine was decreased by esterification of the carboxy group of gallic acid, and in the absence or by the methylation of the o-dihydroxy group. Caffeic acid inhibited the vasorelaxation, though the effect was smaller than that of gallic acid. These findings indicate that gallic acid produces a potentiation of contractile response and inhibition of vasorelaxant responses, probably through inactivation of nitric oxide (NO), in which endothelially produced NO is principally involved, and that the modification of functional groups of the gallic acid molecule abolishes the potentiation of contractile response and attenuates the inhibition of vasorelaxant responses.

Acetylcholine↗
PubMed1992

Characterization of bispecific caffeic acid/5-hydroxyferulic acid O-methyltransferase from aspen.

Bispecific O-methyltransferase (OMT, EC 2.1.1.68) which catalyses the meta-specific methylation of caffeic acid and 5-hydroxyferulic acid was purified to homogeneity from the developing secondary xylem of aspen (Populus tremuloides). The enzyme was purified by conventional techniques and affinity chromatography on S-adenosyl-L-homocysteine agarose using substrate elution. The enzyme has a M(r) of 40,000 as determined by SDS-PAGE. Amino acid sequences of three peptides produced from a proteolytic digest of bispecific OMT were obtained by automated Edman degradation. Polyclonal antibodies raised against the purified OMT reacted strongly to OMT in both purified and unpurified fractions in western blots. Addition of an equal concentration of anti-OMT IgG to crude extract protein inhibited OMT activity by more than 70%.

Amino Acid Sequence↗
PubMed1996

Determination of some pharmacologically active phenolic acids in juices by high-performance liquid chromatography.

Several phenolic acids, e.g. caffeic acid, chlorogenic acid, ferulic acid, gallic acid and ellagic acid, which occur naturally, are inhibitors of carcinogenesis. In this paper we present a new method for the simultaneous determination of all of these compounds, except ellagic acid, in juices by reversed-phase high-performance liquid chromatography (HPLC) using ultraviolet detection and involving isocratic elution, and we have devised an HPLC method for the determination of ellagic acid in juices. The experimental results showed that cherry juice contains a high concentration of chlorogenic acid and the content of bound gallic acid in black and green grape juices is high compared to that of other phenolic acids.

Beverages↗
PubMed1998

Cholesteryl ester hydroperoxide formation in myoglobin-catalyzed low density lipoprotein oxidation: concerted antioxidant activity of caffeic and p-coumaric acids with ascorbate.

Two diet-derived phenolic acids, caffeic and p-coumaric acids, interplayed with ascorbate in the protection of low density lipoproteins (LDL) from oxidation promoted by ferrylmyoglobin. Ferrylmyoglobin, a two-electron oxidation product from the reaction of metmyoglobin and H2O2, was able to oxidize LDL, degrading free cholesterol and cholesteryl esters. Upon exposure to ferrylmyoglobin, LDL became rapidly depleted of cholesteryl arachidonate and linoleate, which turn into the corresponding hydroperoxides. Cholesteryl oleate and cholesterol were, comparatively, more resistant to oxidation. Caffeic (2 microM) and p-coumaric (12 microM) acids efficiently delayed oxidations, as reflected by an increase in the lag times required for linoleate hydroperoxide and 7-ketocholesterol formation as well as for cholesteryl linoleate consumption. At the same concentration, ascorbate, a standard water-soluble antioxidant, was less efficient than the phenolic acids. Additionally, phenolic acids afforded a protection to LDL that, conversely to ascorbate, extends along the time, as inferred from the high levels of cholesteryl linoleate and cholesteryl arachidonate left after 22 hr of oxidation challenging. Significantly, the coincubation of LDL with ascorbate and each of the phenolic acids resulted in a synergistic protection from oxidation. This was inferred from the lag phases of cholesteryl linoleate hydroperoxide (the major peroxide found in LDL) formation in the presence of mixtures of ascorbate with phenolic acids longer than the sum of individual lag phases of ascorbate and the phenolic acids. A similar description could be drawn for the accumulation of a late product of oxidation, 7-ketocholesterol. It is concluded that ferrylmyoglobin induces a typical pattern of LDL lipid peroxidation, the oxidation rate of cholesteryl esters being a function of unsaturation; furthermore, there is a synergistic antioxidant activity of diet-derived phenolic acids with ascorbate in the protection of LDL from oxidation, a finding of putative physiological relevance.

Animals↗
PubMed2002

Induction of antioxidant flavonol biosynthesis in fresh-cut potatoes. Effect of domestic cooking.

The effect of fresh-cutting and subsequent cold storage on phenolic compounds from five long-term-stored potato cultivars (Agria, Cara, Liseta, Monalisa, and Spunta) was studied. Fresh-cutting induced the biosynthesis of three flavonols, which were identified by HPLC-DAD-ESIMS as quercetin 3-rutinoside, quercetin 3-diglucoside, and quercetin 3-glucosylrutinoside. The flavonols were detected after a lag period of 3 days of cold storage. The content ranged from 6 to 14 mg/100 g of fresh weight depending on the cultivar after 6 days of storage. Chlorogenic acid as the main caffeic acid derivative and the amino acids tyrosine and tryptophan were also quantified. The effect of cold storage under light or in dark was studied with new-season-harvested Monalisa potatoes. The flavonol induction was higher in fresh-cut potatoes stored under light than in the dark. However, caffeic acid derivatives were not affected. Domestic cooking such as boiling, microwaving, and frying provoked a partial loss of the flavonols, which were retained in the range of 4-16 mg per serving (213 g). Steam-cooking resulted in the highest retention of caffeic acid derivatives and aromatic amino acids compared with the other cooking methods studied. This means that due to the large amount of potatoes consumed in the Western diet, fresh-cut potatoes can be a significant source of health-promoting phenolics.

Antioxidants↗
PubMed2004

Chemical and biological characterization of cinnamic acid derivatives from cell cultures of lavender (Lavandula officinalis) induced by stress and jasmonic acid.

Cell cultures of lavender (Lavandula officinalis) were analyzed for the metabolite profile under normal growth conditions and under stress as well as after jasmonic acid treatment. The main compound synthesized was rosmarinic acid, which was also secreted into the culture medium. Different solvent extraction methods at different pH values altered the profile slightly. Anoxic stress induced the synthesis of a cinnamic acid derivative, which was identified as caffeic acid by gas chromatography-mass spectrometry. Caffeic acid was also induced after treatment of the cell cultures with jasmonic acid. Although the antioxidative activity of both compounds, rosmarinic acid and caffeic acid, was confirmed in an assay using 2,2-diphenyl-1-picrylhydrazyl (DPPH), it was demonstrated that both substances have a low cytotoxic potential in vitro using acute myeloid leukemia (HL-60) cells. The potential of the system for finding new bioactive compounds is discussed.

Antioxidants↗
PubMed2003

Flavoring components of raw monsooned arabica coffee and their changes during radiation processing.

Volatile aroma principles, nonvolatile taste constituents (caffeine and chlorogenic and caffeic acids), and glycosidically bound aroma compounds of monsooned and nonmonsooned raw arabica coffee were analyzed using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). Among the most potent odor active constituents known to contribute to the aroma of the green beans, 3-isopropyl-2-methoxypyrazine, 3-isobutyl-2-methoxypyrazine, 4-vinylguaiacol, beta-damascenone, (E)-2-nonenal, trans,trans-2,4-decadienal, phenylacetaldehyde, and 3-methylbutyric acid were detected by GC-MS in both samples. A decrease in content of methoxypyrazines and an increase in 4-vinylguaiacol and isoeugenol resulted in a dominant spicy note of monsooned coffee. These phenolic compounds exist partly as their glycosides, and their release from the bound precursors during monsooning accounted for their higher content in monsooned coffee. A considerable decrease in astringent chlorogenic acid as a consequence of hydrolysis to bitter caffeic acid was noted in monsooned coffee. Radiation processing of nonmonsooned beans at a dose of 5 kGy resulted in an increased rate of monsooning. At this dose a quantitative increase in most of the aroma active components could be observed in all samples studied. Hydrolysis of chlorogenic acid to caffeic acid was noted in radiation-processed monsooned coffee beans irrespective of whether the treatment was carried out before or after monsooning. These changes were, however, not observed in irradiated, nonmonsooned coffee beans, suggesting an enzymatic rather than a radiolytic cleavage of chlorogenic acid. A rationale behind the mechanism of monsooning and radiation-induced enhancement of the monsooning process is discussed.

Caffeic Acids↗
PubMed2003

Effect of propolis on human cartilage and chondrocytes.

Propolis, a natural product derived from plant resins collected by the honeybees, has been used for thousands of years in folk medicine for several purposes. The extract that contains amino acids, phenolic acids, phenolic acid esters, flavonoids, cinnamic acid, terpenes and caffeic acid, possesses several biological activities such as anti-inflammatory, immunostimulatory, anti-viral and anti-bacterial. In this study, we assay the effects of propolis extract on the production of key molecules released during chronic inflammatory events as nitric oxide (NO) and glycosaminoglycans (GAGs) in cultures of human cartilaginous tissues and chondrocytes, stimulated with interleukin-1beta (IL-1beta). We observed that this natural compound and its active principle, caffeic acid phenethyl ester (CAPE), were able to contrast the harmful effects of IL-1beta. Our data clearly demonstrated the protective action of propolis in cartilage alteration, that appears greater than that elicited by indomethacin, commonly employed in joint diseases.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Antiproliferative and apoptotic effects of selective phenolic acids on T47D human breast cancer cells: potential mechanisms of action.

INTRODUCTION: The oncoprotective role of food-derived polyphenol antioxidants has been described but the implicated mechanisms are not yet clear. In addition to polyphenols, phenolic acids, found at high concentrations in a number of plants, possess antioxidant action. The main phenolic acids found in foods are derivatives of 4-hydroxybenzoic acid and 4-hydroxycinnamic acid. METHODS: This work concentrates on the antiproliferative action of caffeic acid, syringic acid, sinapic acid, protocatechuic acid, ferulic acid and 3,4-dihydroxy-phenylacetic acid (PAA) on T47D human breast cancer cells, testing their antioxidant activity and a number of possible mechanisms involved (interaction with membrane and intracellular receptors, nitric oxide production). RESULTS: The tested compounds showed a time-dependent and dose-dependent inhibitory effect on cell growth with the following potency: caffeic acid > ferulic acid = protocatechuic acid = PAA > sinapic acid = syringic acid. Caffeic acid and PAA were chosen for further analysis. The antioxidative activity of these phenolic acids in T47D cells does not coincide with their inhibitory effect on tumoral proliferation. No interaction was found with steroid and adrenergic receptors. PAA induced an inhibition of nitric oxide synthase, while caffeic acid competes for binding and results in an inhibition of aryl hydrocarbon receptor-induced CYP1A1 enzyme. Both agents induce apoptosis via the Fas/FasL system. CONCLUSIONS: Phenolic acids exert a direct antiproliferative action, evident at low concentrations, comparable with those found in biological fluids after ingestion of foods rich in phenolic acids. Furthermore, the direct interaction with the aryl hydrocarbon receptor, the nitric oxide synthase inhibition and their pro-apoptotic effect provide some insights into their biological mode of action.

Apoptosis↗
PubMed2002

[Identification of chemical structure of antibacterial components against Legionella pneumophila in a coffee beverage].

We previously reported that certain constituents in brewed coffee exhibited antibacterial activities against a strain of Legionella pneumophila. The constituents showing antibacterial activities were included only in extracts cold with water or hot water. To determine the antibacterial substances in coffee extract, the extract was fractionated by HPLC using a UV/photodiode array detector. The optimum HPLC conditions for analysis were UV wavelength of 250 nm and eluents of methanol/acetic acid (10/90), pH 3.0. When several fractions separated by HPLC were investigated for antibacterial activities against L. pneumophila, it was found that three peak fractions exhibited strong antibacterial activities. Each product from these fractions was analyzed by NMR and LC-mass spectrometry, and the chemical structure of each was determined. It was shown that the antibacterial substances was were protocatechuic acid (3,4-dihydroxy benzoic acid), chlorogenic acid, and caffeic acid.

Beverages↗
PubMed2006

Direct and indirect mechanism(s) of antitumour activity of propolis and its polyphenolic compounds.

The immunomodulatory actions of a water-soluble derivative of propolis (WSDP) and two components of propolis, caffeic acid (CA) and caffeic acid phenethyl ester (CAPE) were investigated. Oral administration (50 mg/kg) of WSDP, CA, and CAPE enhanced the weight and cellularity of the spleen (p<0.05, p<0.01) of treated mice. The response of spleen cells to polyclonal mitogens (PHA, Con A, PWM) was also increased in mice treated with WSDP as compared to control (p<0.01); in contrast, the response of spleen cells of mice treated with CA were significantly suppressed (p<0.001). The colony forming ability of HeLa cells plated on monolayers of macrophages was completely inhibited by peritoneal macrophages from mice receiving either WSDP, CAPE, or CA. Macrophages from treated mice also inhibited [3H]TdR incorporation into HeLa cells in vitro. Testing for the possible presence of NO in the supernatants of 24 hours cultured macrophages activated with either compound revealed that the toxicity of these cells to HeLa cells was in part due to the production of NO. Tumour growth was suppressed by WSDP and its polyphenolic compounds given orally to mice. Local presence of CA, and CAPE in the tissue, caused a significant delay of tumour formation. Based on these results, we postulate that the antitumour activity of the test compounds includes pronounced immunomodulatory activity mainly due to the augmentation of non-specific antitumour resistance in mice via macrophage activation and the production of soluble factors by those cells which may interfere with either cells of the immune system or directly by tumour cells.

Animals↗
PubMed1998

Effect of dietary phenolic compounds on apoptosis of human cultured endothelial cells induced by oxidized LDL.

1. Oxidized low density lipoproteins (LDL) are toxic to cultured endothelial cells. Mildly oxidized LDL, characterized by relatively low levels of TBARS and only minor modifications of apoB, were obtained by using 2 experimental model systems of oxidation, namely oxidation by u.v. radiation or ferrylmyoglobin (a two electron oxidation product from the reaction of metmyoglobin with H2O2). 2. Toxic concentrations of mildly oxidized LDL induce apoptosis (programmed cell death) of cultured endothelial cells, as shown by typical morphological features, by the in situ TUNEL procedure and by DNA fragmentation revealed on gel electrophoresis. This apoptosis is calcium-dependent and subsequent to the intense and sustained cytosolic [Ca2+]i peak elicited by oxidized LDL. 3. Five naturally occurring phenolic compounds present in food and beverages were able to prevent, in a concentration-dependent manner, the apoptosis of endothelial cells induced by oxidized LDL. Among the compounds tested, caffeic acid was the most effective. Under the conditions used, the protective effect of caffeic acid (IC50 8.3+/-2.1 micromol l[-1]) in the prevention of apoptosis induced by oxidized LDL was significantly higher than that of the other compounds tested (IC50s were 12.4+/-3.2, 14.1+/-4.1, 20.4+/-4.4 and 72.6+/-9.2 micromol l(-1) for ferulic, protocatechuic, ellagic and p-coumaric acids, respectively). 4. The anti-apoptotic effect of caffeic acid results from the addition of two effects, (i) the antioxidant effect which prevents LDL oxidation and subsequent toxicity ('indirect' protective effect); (ii) a 'direct' cytoprotective effect, acting at the cellular level. 5. Effective concentrations of caffeic acid acted at the cellular level by blocking the intense and sustained cytosolic [Ca2+]i rise elicited by oxidized LDL. 6. In conclusion, phenolic acids (caffeic and ferulic acids being the most potent of the compounds tested under the conditions used) exhibit a potent cytoprotective effect of cultured endothelial cells against oxidized LDL. In addition to antioxidant effect delaying LDL oxidation, caffeic acid acts as a cytoprotective agent, probably by blocking the intracellular signalling triggered by oxidized LDL and culminating in the sustained calcium rise which is involved in oxidized LDL-induced apoptosis.

Antioxidants↗
PubMed2004

Effects of chlorogenic acid and its metabolites on the sleep-wakefulness cycle in rats.

The effect of chlorogenic acid on the sleep-wakefulness cycle in rats was investigated in comparison with those of caffeic acid (the metabolite of chlorogenic acid) and dihydrocaffeic acid (the metabolite of caffeic acid). A significant prolongation of sleep latency was observed with chlorogenic acid and caffeic acid at a dose of 500 and 200 mg/kg, respectively. On the other hand, no remarkable effects were observed with dihydrocaffeic acid even at a dose of 500 mg/kg. Caffeine caused a significant increase in sleep latency and waking time and decrease in non-rapid eye movement sleep time at a dose of 10 mg/kg. In contrast, chlorogenic acid and its metabolites had no significant effects on each sleep state. From these results, it may be concluded that chrologenic acid caused a mild arousal effect compared with that of caffeine, and the effect of chlorogenic acid may have occurred through its metabolite caffeic acid.

Animals↗
PubMed2004

Identification and quantitation of compounds in a series of allelopathic and non-allelopathic rice root exudates.

An investigation of the chemical basis for rice allelopathy to the rice weed arrowhead (Sagittaria montevidensis) was undertaken using GC/MS and GC/MS/MS techniques. Twenty-five compounds were isolated and identified from the root exudates of both allelopathic and non-allelopathic rice varieties. Phenolics, phenylalkanoic acids, and indoles were among the chemical classes identified. Two indoles previously unreported in rice were detected in the exudates, 5-hydroxy-2-indolecarboxylic acid and 5-hydroxyindole-3-acetic acid. Several other compounds identified in this study have not previously been reported in rice root exudates, namely mercaptoacetic acid, 4-hydroxyphenylacetic acid, and 4-vinylphenol. The levels of 15 compounds present in the exudates were quantified using GC/MS/MS. Six of the seven most abundant compounds were phenolic acids. Significant differences exist between the allelopathic and non-allelopathic cultivars in their production of three of these six compounds. Greater amounts of trans-ferulic acid, p-hydroxybenzoic acid, and caffeic acid were detected in the exudates of allelopathic cultivars. The seventh compound, abietic acid, was significantly higher in the non-allelopathic cultivars.

Abietanes↗