Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Caffeic Acids”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1997

Floral scent production in Clarkia breweri (Onagraceae). II. Localization and developmental modulation of the enzyme S-adenosyl-L-methionine:(iso)eugenol O-methyltransferase and phenylpropanoid emission.

We have previously shown (R.A. Raguso, E. Pichersky [1995] Plant Syst Evol 194: 55-67) that the strong, sweet fragrance of Clarkia breweri (Onagraceae), an annual plant native to California, consists of 8 to 12 volatile compounds, including 4 phenylpropanoids. Although some C. breweri plants emit all 4 phenylpropanoids (eugenol, isoeugenol, methyleugenol, and isomethyleugenol), other C. breweri plants do not emit the latter 2 compounds. Here we report that petal tissue was responsible for the bulk of the phenylpropanoid emission. The activity of S-adenosyl-L-methionine: (iso)eugenol O-methyltransferase (IEMT), a novel enzyme that catalyzes the methylation of the para-4'-hydroxyl of both eugenol and (iso)eugenol to methyleugenol and isomethyleugenol, respectively, was also highest in petal tissue. IEMT activity was absent from floral tissues of plants not emitting (iso)methyleugenol. A C. breweri cDNA clone encoding IEMT was isolated, and its sequence was shown to have 70% identity to S-adenosyl-L-methionine:caffeic acid O-methyltransferase. The protein encoded by this cDNA can use eugenol and isoeugenol as substrates, but not caffeic acid. Steady-state IEMT mRNA levels were positively correlated with levels of IEMT activity in the tissues, and no IEMT mRNA was observed in flowers that do not emit (iso)methyleugenol. Overall, the data show that the floral emission of (iso)methyleugenol is controlled at the site of emission, that a positive correlation exists between volatile emission and IEMT activity, and that control of the level of IEMT activity is exerted at a pretranslational step.

Amino Acid Sequence↗
PubMed1994

Effect of dietary caffeic and chlorogenic acids on in vivo xenobiotic enzyme systems.

The plant phenols chlorogenic and caffeic acids were tested for their affinity to alter hepatic and intestinal xenobiotic Phase I and Phase II enzyme activities in mice. Mice were fed isocaloric and isonitrogenous powdered diets containing 0 and 0.2% caffeic and chlorogenic acids, respectively. Animals pre-treated with benzo(a)pyrene (B(a)P) were sacrificed 18 h after an oral dose (50 mg/kg Bwt). B(a)P induced animals exhibited higher (p < 0.05) microsomal AHH, UDPGT, P-450 and cytosolic GST liver enzyme activities. The presence of these phenolics in the diet was shown to have little effect in modulating hepatic xenobiotic activating-detoxification enzymes. The dietary intake of caffeic and chlorogenic acids was particularly evident with intestinal xenobiotic AHH and GST enzyme activity. These data indicate that the presence of caffeic and chlorogenic acids in the diet may have an integral role in modulating the carcinogenic potential of reactive xenobiotics such as B(a)P.

Administration, Oral↗
PubMed1999

Evaluation of the 'antioxidant power' of olive oils based on a FIA system with amperometric detection.

A new method for the evaluation of the 'total antioxidant power' of olive oils, based on a flow injection analysis system with electrochemical detection, is described. It represents a attractive alternative to the mostly used Rancimat method since it is based on the chemical structure of antioxidants and does not require the manipulation of several parameters, such as temperature and oxygen pressure, to accelerate oil oxidation. The proposed procedure is simple, rapid, allows a throughput of 90 samples h-1 and provides a good precision: an RSD of 3.5% was obtained for caffeic acid at the concentration level of 5 mg L-1 (n = 12). A comparison of the proposed was obtained for caffeic acid at the concentration level of 5 mg L-1 (n = 12). A comparison of the proposed procedure with two other methods (Rancimat method and ABTS.+ decoloration assay) was performed to investigate the applicability and limitations of the proposed method.

Antioxidants↗
PubMed2005

Effects of Choto-san and its related constituents on endogenous antioxidant systems.

We previously reported that Choto-san acts as an antioxidant and cytoprotective agents against H2O2-induced oxidative damage in NG108-15 cells, and the effect is due at least partly to the phenolic compounds. To further investigate the detail mechanisms of this cytoprotection effects of Choto-san and related compounds on enzyme activities of antioxidant systems were examined. Choto-san (5-100 microg/ml) and Chotoko (5-100 mg/ml) stimulated the activity of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPX). These also increased the level of glutathione. Although Choto-san without Chotoko (w/o CKO) did not show the effects on SOD and catalase, GPX activity and glutathion content also, but weakly, stimulated by w/o CKO. The effects of phenolic compounds, epicatechin, caffeic acid and quercetin were also investigated. Epicatechin stimulated catalase, GPX and glutathion content, but not SOD. On the other hand, caffeic acid stimulated SOD activity but had no effects on others. Quercetin stimulated all, although intensities were different among. These results suggest that simultaneous induction of cellular antioxidant defense systems by Choto-sam and its related constituents may be an important mechanisms underlying the protective effects of Choto-san on ischemia-induced neuronal cells injury, and the characteristics of the stimulative effects of phenolic compounds were depend on enzymes.

Antioxidants↗
PubMed2003

Two O-methyltransferases isolated from flower petals of Rosa chinensis var. spontanea involved in scent biosynthesis.

Rosa chinensis var. spontanea predominantly emits 1,3,5-trimethoxybenzene together with methyleugenol and isomethyleugenol as minor floral scent compounds. Two O-methyltransferases (OMTs), designated as RcOMT1 and RcOMT2, were isolated from rose flower petals using homology-based screening strategies. RcOMT1 efficiently methylated eugenol and isoeugenol to yield volatile methyleugenol and isomethyleugenol, respectively. Furthermore, the mRNA transcripts of RcOMT1 were highly expressed in floral organs and the expression pattern coincided with intracellular content changes of methyleugenol and isomethyleugenol in rose flowers. In contrast, RcOMT2, which shows 94% similarity with caffeic acid O-methyltransferase (COMT) of Prunus amygdalus, was expressed in all tissues tested and had the highest activity with caffeic acid, a typical substrate for COMT. However, this COMT-like OMT also showed some degrees of activity with all three putative precursors of 1,3,5-trimethoxybenzene.

Journal Article↗
PubMed1985

Enhancement of endogenous production of 12-L-hydroxy-5,8,10,14-eicosatetraenoic acid in aortic smooth muscle cells by platelet-derived growth factor.

Platelet-derived growth factor (PDGF) has a chemotactic effect on smooth muscle cells, which is inhibited by lipoxygenase inhibitor caffeic acid. In order to study the role of endogenous lipoxygenase products of arachidonic acid on the chemotactic action of PDGF, effects of PDGF on the lipoxygenase pathway in smooth muscle cells were examined. Lipoxygenase products were analyzed by high-performance liquid chromatography. 15-, 5- and 12-lipoxygenase activities, in order of magnitude, were found in smooth muscle cell homogenate. However, when the lipoxygenase products were analyzed using intact cells prelabelled with [14C]arachidonic acid, only 12-L-hydroxy-5,8,10,14-eicosatetraenoic acid (HETE) was found to be produced endogenously. In addition, 12-HETE was not released into the medium. Treatment of the cells with PDGF increased the endogenous production of 12-HETE. The amounts of intracellular 12-HETE in PDGF-treated cells were 126, 132 and 146% at 1, 3, and 10 hr's after the initiation of PDGF treatment, respectively, when control value at each time point was considered as 100%. Caffeic acid (10(-4) M) completely inhibited the PDGF effect on 12-HETE production. However, PDGF treatment did not significantly alter the 12-lipoxygenase activity. These results suggest that the stimulatory effect of PDGF on 12-HETE production was not mediated by the activation of 12-lipoxygenase activity. Since 12-HETE itself is a potent chemoattractant for smooth muscle cells, the present dat strongly suggest that 12-HETE could be an important intracellular mediator of the chemotactic action of PDGF on aortic smooth muscle cells.

Animals↗
PubMed1998

Modulation by phytochemicals of cytochrome P450-linked enzyme activity.

Compounds derived from plant sources with putative anticancer properties were studied for their effects on alkoxyresorufin O-dealkylase activity, a measure of cytochrome P450 activity. The phytochemicals investigated included benzyl isothiocyanate, caffeic acid, chlorogenic acid, diosmin, ferulic acid, indole-3-carbinol, phenethyl isothiocyanate and resveratrol. Each phytochemical at concentrations of 0.25 and 0.5 microM was incubated with 0.2 mg hamster liver microsomal protein and 0.5 microM concentrations of benzyloxyresorufin, ethoxyresorufin and methoxyresorufin. Three of the phytochemicals tested, namely benzyl isothiocyanate, phenethyl isothiocyanate and resveratrol, exhibited potent inhibition of alkoxyresorufin O-dealkylase activity. Benzyl isothiocyanate inhibited benzyloxyresorufin O-dealkylase (BROD) activity, ethoxyresorufin O-deethylase (EROD) activity and methoxyresorufin O-demethylase (MROD) activity by 90% at both the 0.25 and 0.5 microM concentrations. Phenethyl isothiocyanate inhibited BROD activity by 69%, EROD activity by 90% and MROD activity by 94% at both concentrations tested. Resveratrol inhibited BROD activity by 69% at the 0.25 microM concentration and by 78% at the 0.5 microM concentration. It inhibited EROD activity by 60% at the 0.25 microM concentration and by 80% at the 0.5 microM concentration. Resveratrol exhibited the greatest inhibitory action toward MROD, i.e. 76% and 84% at the two concentrations tested. Chlorogenic acid significantly affected BROD, EROD and MROD activity only at the 0.5 microM concentration inhibiting by 51%, 47% and 54%, respectively. Caffeic acid affected BROD and MROD activity at 0.5 microM only inhibiting BROD activity by 46% and MROD activity by 40%. Diosmin inhibited EROD activity by 11% at the 0.25 microM concentration and by 61% at 0.5 microM. It inhibited MROD by 47% and 54% at the two concentrations tested but did not significantly alter BROD activity. Ferulic acid significantly inhibited EROD and MROD activity at the 0.5 microM concentration by 28% and 32%, respectively. Indole-3-carbinol significantly inhibited BROD activity by 26% at 0.25 microM and by 42% at 0.5 microM. It inhibited EROD and MROD activity by 28% and 29% at 0.5 microM, respectively. The alkoxyresorufin O-dealkylase reactions are selective for various isoforms of cytochrome P450. Our results suggest that the phytochemicals we tested have varied effects on the enzymatic activity of isoforms of cytochrome P450 that dealkylate benzyloxyresorufin, methoxyresorufin and ethoxyresorufin and therefore may have varied effects on the metabolism of substrates for these isoforms.

Animals↗
PubMed2006

[Studies on chemical constituents of cytotoxic fraction from leaves of Elaeagnus pungens].

OBJECTIVE: To study the chemical constituents possessing cytotoxicity activity from Elaeagnus pungens. METHOD: The constituents were separated through repeated chromatographic methods and their structures were elucidated by spectral analysis. RESULT: Five compounds were isolated from the ethyl acetate ether extract of leaves of E. pungens. Their structures were elucidated as 4-hydroxybenzoic acid (1), 3, 3'-dimethoxyquercetin (2), caffeic acid methyl ester (3), methyl 3, 4-dihydroxybenzoate (4), spingic acid (5), 4-methoxylbenzoic acid (6), 3-methylkaempferol (7), kaempferol-3-O-beta-D-glucoside (8), dausosterol (9). CONCLUSION: Compounds 1-8 were isolated from this plant for the first time.

Caffeic Acids↗
PubMed2005

Chemical constituents of Lychnophora pohlii and trypanocidal activity of crude plant extracts and of isolated compounds.

Crude extracts of Lychnophora pohlii were tested in vitro against trypomastigote forms of Trypanosoma cruzi, and the dichloromethane and methanol crude extracts from leaves plus inflorescences were found to have trypanocidal activity. The bioassay-guided fractionation of the extracts yielded seven active compounds: the sesquiterpene lactones lychnopholide, centratherin, goyazensolide and 15-desoxygoyazensolide in the dichloromethane extract, and caffeic acid and the flavonoids luteolin and vicenin-2 in the methanol extract. One active caffeoyl quinic acid derivative was isolated from the inactive hydroalcoholic extract of leaves plus inflorescences. Chemically, the plant has sesquiterpene lactone type furanoheliangolides, flavonoids, caffeic acid, a caffeoyl quinic acid derivative, which are characteristic of the Vernonieae.

Animals↗
PubMed2004

Antioxidant effects of dihydrocaffeic acid in human EA.hy926 endothelial cells.

Dihydrocaffeic acid (DHCA) is a metabolite of caffeic acid with potent antioxidant properties. Since DHCA has been detected in human plasma following coffee ingestion, we tested the hypothesis that DHCA protects the endothelium from oxidative stress in a model in human-derived EA.hy926 endothelial cells. During culture for 16-24 hours, the cells accumulated DHCA against a concentration gradient to low millimolar concentrations. In alpha-tocopherol-loaded cells, DHCA spared alpha-tocopherol during overnight culture in a dose-dependent manner. In response to oxidant stress induced by a water-soluble free radical initiator, both alpha-tocopherol and DHCA diminished oxidation of cis-parinaric acid that had been incorporated into the cells, although their antioxidant activities were not additive. DHCA also decreased intracellular oxidation of dihydrofluorescein due to redox cycling by menadione. This suggests that the protective effects of DHCA were caused by scavenging of intracellular reactive oxygen species. DHCA also increased nitric oxide synthase activity in a dose-dependent manner in cultured cells, which was associated with a comparable increase in endothelial nitric oxide synthase protein. Although the DHCA concentrations required for these effects are higher than those likely to be present in plasma or the interstitium, these results indicate that DHCA can function as an intracellular antioxidant.

Antioxidants↗
PubMed1988

Effects of subsequent antioxidant treatment on 7,12-dimethylbenz[a]anthracene-initiated carcinogenesis of the mammary gland, ear duct and forestomach in Sprague-Dawley rats.

The effects of the antioxidants tetramethyl-p-phenylenediamine (TMPD), propyl gallate (PG), quercetin (QC), 2-tert-butyl-4-methylphenol (TBMP), tert-butylhydroquinone (TBHQ), 3,3'-thiodipropionic acid (TDPA), guaiac gum (GG) and caffeic acid (CA) on 7,12-dimethylbenz[a]anthracene (DMBA)-initiated mammary gland, ear duct and forestomach carcinogenesis were examined in female Sprague--Dawley rats. Fifty-day-old rats were treated with 2.5 mg/100 g body wt of DMBA and, commencing 1 week thereafter, were given diets supplemented with 0.1% TMPD, 1.0% PG, 1.0% QC, 1% TBMP, 0.8% TBHQ, 1.0% TDPA, 1.0% GG or 0.5% CA for 51 weeks and then killed. Mammary tumor development was reduced by diet containing TMPD, PG, TBMP, TBHQ or GG, although this could be partly due to antioxidant treatment-associated decrease in body wt gain. The incidence of ear duct tumors was not affected by any of the antioxidant treatments. Development of forestomach tumors was enhanced in the group given DMBA followed by CA.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1985

Lipoxygenase specific inhibitors inhibit murine lymphocyte reactivity to Con A by reducing IL-2 production and its action.

Caffeic acid and AA861, specific inhibitors of lipoxygenase, reduced reactivity of murine spleen lymphocytes to Concanavalin A (Con A). They inhibited interleukin-2 (IL-2) production and its action, although they did not inhibit acquisition of lymphocyte reactivity to IL-2. Indomethacin was not able to restore the reactivity of lymphocytes to Con A even when it was combined with lipoxygenase specific inhibitors. This result suggests that lipoxygenase inhibitors exert their effects not through increasing prostaglandin E2 (PGE2) production but through inhibiting lipoxygenase. Lipoxygenase inhibitors exerted their effects even though they were removed 24 hr after the onset of culture. Taken together, these results suggest that lipoxygenase inhibitors exerted their inhibitory effects in the early period of lymphocyte activation by reducing IL-2 production and its action, implying that lipoxygenase reactions during 24 hr after stimulation may be involved in these steps.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed2005

Occurrence of yellow mosaic geminiviral disease on bitter gourd (Momordica charantia) and its impact on phytochemical contents.

Natural occurrence of yellow mosaic disease was observed on bitter gourd (Momordica charantia). Association of geminivirus with the disease was investigated through polymerase chain reaction using geminivirus-specific primers and Southern hybridization with a probe prepared from the cloned DNA of a known geminivirus. The fruits, leaves and stem of infected and healthy plants were studied for phytochemical composition. The amounts of protein were 49%, 50% and 66% higher, total carotenoids were 36%, 33% and 40% lower, vitamin C were 23%, 48% and 50% lower, total phenols were 28%, 31% and 43% lower, and antioxidant activity were 36%, 48% and 43% lower in the severely virus infected fruits, leaves and stem, respectively, as compared with healthy plants. The loss in the quantity of these phytochemicals was also observed even in mild infected plants, which further increased with the severity of the symptoms. Similarly, ethanol and 50% ethanol soluble extractive were also 25-43% lower in the fruits, leaves and stem of infected plants as compared with the healthy plants. A 45% and 54% lower caffeic acid, and 78% and 59% lower amounts of ferulic acid in the fruits and stem, respectively, and a 25% loss of gallic acid were noticed in the leaves of the severely infected plants.

Antioxidants↗
PubMed1999

Identification of specific residues involved in substrate discrimination in two plant O-methyltransferases.

Among the large number of plant O-methyltransferases that are involved in secondary metabolism, only a few have been enzymatically characterized, and little information is available on the structure of their substrate binding site and the mechanism which determines their substrate specificity and methylation regiospecificity. We have previously reported the isolation of two O-methyltransferases, S-adenosyl-l-methionine:(iso)eugenol O-methyltransferase (IEMT) and S-adenosyl-l-methionine:caffeic acid O-methyltransferase (COMT) from Clarkia breweri, an annual plant from California. While IEMT and COMT (which methylate eugenol/isoeugenol and caffeic acid/5-hydroxyferulic acid, respectively) share 83% identity at the amino acid level, they have distinct substrate specificity and methylation regiospecificity. We report here that seven amino acids play a critical role in discriminating between eugenol/isoeugenol and caffeic acid/5-hydroxyferulic acid. When these amino acids in IEMT were replaced by the corresponding residues of COMT, the hybrid protein showed activity only with caffeic acid/5-hydroxyferulic acid. Conversely, when these amino acids in COMT were replaced by corresponding IEMT residues, the hybrid protein had activity only with eugenol/isoeugenol. These results provide strong evidence that O-methyltransferase substrate preference could be determined by a few amino acid residues and that new OMTs with different substrate specificity could begin to evolve from an existing OMT by mutation of a few amino acids. Phylogenetic analysis confirms that C. breweri IEMT evolved recently from COMT.

Amino Acid Sequence↗
PubMed1988

Reductive release of ferritin iron: a kinetic assay.

Ferritin iron release, a process of considerable interest in biology and medicine, occurs most readily in the presence of reducing agents. Here is described a kinetic assay for measuring the rate of ferritin iron removal promoted by various reductants. The new procedure uses ferrozine as a chromophoric, high-affinity chelator for the product, Fe(II). The initial rate of iron release is quantified by continuous spectrophotometric measurement of the Fe(ferrozine)2/3+ complex which absorbs maximally at 562 nm. The initial rate of iron mobilization is dependent on reductant concentration, but not on the concentration of the chelating agent, ferrozine. Saturation kinetics are observed for all reductants, including dihydroxyfumarate, cysteine, caffeic acid, ascorbate, and glutathione. Superoxide dismutase greatly inhibits ferritin iron release by ascorbate, but has little or no effect on the reducing action of dihydroxyfumarate, cysteine, caffeic acid, or glutathione. Ferritin iron removal by dihydroxyfumarate was inhibited by various metal ions. This new assay may be used for rapid screening of test compounds for treatment of iron overload and for investigation of the mechanistic aspects of ferritin iron reduction.

Animals↗
PubMed1988

Arachidonic acid metabolism and casein secretion in lactating rabbit mammary epithelial cells: effects of inhibitors of prostaglandins and leukotrienes synthesis.

The metabolism of arachidonic acid (AA) in fragments of lactating rabbit mammary glands in vitro was studied by considering the distribution of 13-[14C]AA in the cells, and the effects of inhibitors of cyclooxygenase and lipoxygenase pathway on the basal and prolactin (PRL)-stimulated casein secretion. 13-[14C]AA was incorporated in all classes of lipids and PRL increased transiently the percentage of free fatty acid after 1 and 5 min. Ten microM ETYA (5,8,11,14-Eicosatetraynoic acid), a tetrayne analogue of AA inhibited prostaglandins F2 alpha (PGF2 alpha) production but not leukotrienes B4 and C4 (LTB4 and LTC4) production and increased basal casein secretion. 10(-4) M DCHA (Docosahexaenoic acid) a competitive inhibitor of prostaglandin-synthetase inhibited PGF2 alpha production but did not affect basal nor PRL-stimulated casein secretion. Fourteen microM indomethacin inhibited PGF2 alpha and LTC4 production and PRL-stimulated casein secretion. Ten microM NdgA (nordihydroguaiaretic acid) an inhibitor of lipoxygenase pathway, inhibited LTB4 and LTC4 production, increased basal level of casein secretion and inhibited PRL-stimulated casein secretion. Hundred microM caffeic acid, an inhibitor of glutathione-S-transferase (GST), a class of enzymes implied in the transformation of LTA4 into LTC4, had the same effect that NDGA on basal and PRL-stimulated casein secretion. These findings show that inhibitors of AA metabolites alter casein secretion.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed2000

Individual and combined antioxidant effects of seven phenolic agents in human erythrocyte membrane ghosts and phosphatidylcholine liposome systems: importance of the partition coefficient.

Antioxidant activities of seven phenolic agents against Fe(2+)-induced lipid oxidation were compared with alpha-tocopherol, beta-carotene, and vitamin C in human erythrocyte membrane ghosts and liposome systems. The antioxidant activity of five test flavonoids followed the order catechin > epicatechin > rutin > quercetin > myricetin in both systems (p < 0.05), which was negatively correlated with their partition coefficients. The antioxidant interaction of these phenolic agents with alpha-tocopherol, beta-carotene, or vitamin C in inhibiting Fe(2+)-induced lipid oxidation was examined. Synergistic effects were present in the combinations of alpha-tocopherol plus caffeic acid, catechin, or epicatechin as well as in all combinations of vitamin C plus phenolic antioxidants. On the basis of the stronger individual and combined effects present in caffeic acid, catechin, and epicatechin, the application of these three phenolic agents with or without alpha-tocopherol, beta-carotene, and vitamin C may provide stronger protective benefits against lipid oxidation, which may be helpful for oxidation-related diseases prevention.

Antioxidants↗
PubMed2004

Minocycline protects PC12 cells from ischemic-like injury and inhibits 5-lipoxygenase activation.

Minocycline protects animals against cerebral ischemia by inhibiting inflammation. To determine whether minocycline protects PC12 cells from in vitro ischemic-like injury and affects pro-inflammatory 5-lipoxygenase activation, the cell viability and 5-lipoxygenase translocation to nuclear membrane were observed after oxygen-glucose deprivation (OGD). We found that OGD reduced cell viability, which was attenuated by minocycline and 5-lipoxygenase inhibitor caffeic acid. 5-Lipoxygenase protein was detected in PC12 cells by immunohistochemical and Western blot analyses. OGD induced 5-lipoxygenase translocation to nuclear membranes, which was abolished by minocycline and caffeic acid. Thus, minocycline can protect PC12 cells from in vitro ischemic-like injury, and this effect may be partly related to the inhibition of 5-lipoxygenase activation.

Animals↗