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 1,081 records · Page 60Linked to original sources
PubMed2006

[Non-alkaloid constituents from a Tibetan medicine Meconopsis quintuplinervia].

OBJECTIVE: To study the chemical constituents of a Tibetan medicine Meconopsis quintuplinervia. METHOD: Column chromatographic techniques were applied to isolate constituents. A combination of IR, MS and NMR spectroscopy was used to identify structures of constituents. RESULT: Twelve compounds were isolated from the ethanolic extract and their structures were elucidated as quercetin 3-O-beta-D-glucopyranoside (I), quercetin 3-O-beta-D-galactopyranosyl-(1-->6)-glucopyranoside (II), kaempferol 3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside (III), isorhamnetin 3-0-beta-D-galactopyranosyl-(1-->6)-beta-D-glucopyranoside (IV), caffeic acid (V), protocatechuic acid (VI), p-hydroxycinnamic (VII), 2-(3,4-dihydroxyphenyl )-ethyl-O-beta-D-glucopyranoside (VIII), p-hydroxybenzoyl-beta-D-glucopyranoside (IX), 4-O-beta-D-glucopyranosyl-(Z)-p-coumaric acid (X), 5, 7-dihydroxy-4H-4-chromenone (XI), daucosterol (XII). CONCLUSION: Ten compounds were isolated from this genus for the first time except for XI and XII.

Caffeic Acids↗
PubMed2004

Cytotoxicity of phenolic acid phenethyl esters on oral cancer cells.

Many phenolic acid phenethyl esters possess diverse biological effects including anti-cancer activity. A series of 14 derivatives were synthesized for the evaluation of their cytotoxic effect on oral cancer cells. These derivatives were tested by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric and trypan blue dye exclusion assay on the growth of oral squamous cell carcinoma (SAS), oral epidermoid carcinoma-Meng 1 (OEC-M1), and normal human oral fibroblast (NHOF) cells, respectively. Caffeic acid phenethyl esters, 3a (CAPE), and 3b, 3c, and 3d showed cytotoxic effects on the SAS and OEC-M1 cell lines, but not the NHOF cell line at a 5-100 microM dose range. Flow cytometric analysis showed that 3c caused OEC-M1 cell arrest at G2/M phase. Such differential effects on representative cancer and normal cells suggested these compounds might be useful in oral cancer chemotherapy.

Caffeic Acids↗
PubMed2006

[Studies on phenolic constituents from leaves of pineapple (Ananas comosus)].

OBJECTIVE: To study the phenolic constituents of the leaves of pineapple. METHOD: Chromatographic methods were used to isolate compounds from the leaves of pineapple and spectroscopic methods were used to identify the structures of the isolated compounds. RESULT: 7 compounds, ananasate (1), 1-O-caffeoylglycerol (2), 1-O-p-coumaroylglycerol (3), caffeic acid (4), p-coumaric acid (5), beta-sitosterol (6) and daucosterol (7), were isolated from the leaves of pineapple. CONCLUSION: 1 was a new compound, and others were obtained from this plant for the first time.

Ananas↗
PubMed1992

[HPLC analysis of the active ingredients of Forsythia suspensa].

Forsythia suspensa is a widely used traditional Chinese herb. Because of the need to evaluate its quality, a HPLC method was developed to analyze the active ingredients in its fruits and leaves. One g of powdered plant material was cold macerated over-night with 10 ml of methanol added then supersonic extracted for 20 min. Four ml of the extract were mixed with 1 ml of water, centrifuged (400 x g, 15 min), and then analyzed by HPLC with a Nucleosil C--18 column. The mobile phase for gradient elusion consisted of MeOH(containing 1% tetrahydrofuran) and H2O (containing 0.01 mol/L KH2PO4,pH 3.2) and monitored by UV absorption at 280 nm. The identity and purity of the peaks were checked by photodiode array detector and in comparison with standards. By this procedure, the active constituents caffeic acid, rutin, forsythoside A, forsythin, and forsythigenin were separated successfully, and the quantity of each compound was determined by peak area. Some fruit samples obtained from various sources and the leaf sample made as tea were analyzed by this method.

Caffeic Acids↗
PubMed1984

Detection of reaction products of thiamin degradation by catechol derivatives.

To clarify the mechanism of thiamin degradation by catechol derivatives, thiamin and its analogues were incubated with caffeic acid or catechol in 1/15 M phosphate buffer pH 7.4 at 48 degrees C or 50 degrees C. Using thin-layer chromatography and high-performance liquid chromatography, several unknown intermediates of the reaction product, which may have both pyrimidine and catechol moieties, were detected.

Caffeic Acids↗
PubMedDate not supplied

Biochemical activities of propolis-extracts. III. Inhibition of dihydrofolate reductase.

Ethanolic and aqueous extracts of the natural compound PROPOLIS indicate substantial antiinflammatory functions as well as antibiotic activities in vitro and in vivo. The exact mode of physiological or biochemical mechanisms responsible for the medical effects, however, is all but clear. The standardization on the basis of quantitative determination of prominent components of these extracts have been substituted recently by simple biochemical model reactions including photodynamic properties. In this communication we report on the inhibitory activity of an aqueous extract of propolis on the enzyme dihydrofolate reductase. This activity may at least partially be due to the content of caffeic acid, as revealed by HPLC chromatography and comparative activity tests of representative ingredients of the propolis extract. This result may explain some of the protective functions of propolis, similar to those shown for several "non-steroidal antiinflammatory drugs", NSAIDs.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

Inhibition of neutrophil elastase activity by phenolic compounds from plants.

The influence of 40 phenolic compounds from plants were tested on the enzymatic activity of neutrophil elastase (EC 3.4.21.37). Among the flavonoids especially the compounds with a catecholic structure showed a strong inhibitory activity in the range of mumol/l, hyperosid was the strongest inhibitor with an IC50 of about 0.3 mumol/l. Lipophilic caffeic acid esters and phenolic compounds with catecholic structure elements in general inhibited the enzyme. Because of the specific role of neutrophil elastase in the inflammatory process its inhibition by phenolic natural compounds might be one explanation for the use of medicinal plants containing phenolic compounds in the treatment of inflammation.

Caffeic Acids↗
PubMed1990

Staphylococcal enterotoxin A induced interferon (IFN)-gamma production in spleen cells from BCG-immunized mice: the IFN production is dependent on leukotriene C4 but not dependent on interleukin 2.

In our previous paper, we showed that IFN was induced in sera by injection of staphylococcal enterotoxin A (SEA) in Bacillus Calmette-Guérin (BCG) immunized C57BL/6 (B6) mice. In analyzing the phenomenon in vitro, we showed that SEA induced IFN-gamma in the supernatant of the spleen cell culture from BCG immunized B6 mice and that leukotriene C4 (LTC4) from BCG activated macrophages in the spleen was involved in the IFN production from Ly 1+ T cells. On the other hand, interleukin-2 (IL-2) has reported to play an important role in the regulation of synthesis of IFN-gamma by T cells. In the present study, we examined whether IL-2 is involved in SEA-induced IFN production. The result showed that the SEA-induced IFN-gamma production was observed in spite of suppression of SEA-induced IL-2 production in spleen cells from BCG-immunized B6 mice. On the contrary, the depressed IFN production was observed in spite of high SEA-induced IL-2 production in spleen cells from their control mice. On the other hand, LTC4 production was 8 times higher in spleen cells from BCG-immunized B6 mice, high producer of SEA-induced IFN, than in that from BCG-immunized C3H mice, the low producer. We also observed that the IFN and the LTC4 production of spleen cells from BCG-immunized B6 mice was suppressed in the presence of caffeic acid and nordihydroguaiaretic acid, non-specific lipoxygenase inhibitors, and that LTC4 augmented the IFN production of normal B6 mouse spleen cells in the presence of 2-mercaptoethanol. Therefore, involvement of LTC4 rather than of IL-2 was supported in our experimental system.

Animals↗
PubMed1976

Six-hour pigmentation test for the identification of Cryptococcus neoformans.

Cryptococcus neoformans colonies can be identified within 6 h using paper disks containing caffeic acid and ferric citrate. Indentification is based on the development of a dark brown pigment. Saprophytic Cryptococcus species and common clinically isolated yeasts do not develop the brown color. The concentration of the reagents and the method of storage of the impregnated paper disks are critical for the rapid and specific development of the pigment.

Caffeic Acids↗
PubMed2005

Altered iron homeostasis involvement in arsenite-mediated cell transformation.

Chronic exposure to low doses of arsenite causes transformation of human osteogenic sarcoma (HOS) cells. Although oxidative stress is considered important in arsenite-induced cell transformation, the molecular and cellular mechanisms by which arsenite transforms human cells are still unknown. In the present study, we investigated whether altered iron homeostasis, known to affect cellular oxidative stress, can contribute to the arsenite-mediated cell transformation. Using arsenite-induced HOS cell transformation as a model, it was found that total iron levels are significantly higher in transformed HOS cells in comparison to parental control HOS cells. Under normal iron metabolism conditions, iron homeostasis is tightly controlled by inverse regulation of ferritin and transferrin receptor (TfR) through iron regulatory proteins (IRP). Increased iron levels in arsenite transformed cells should theoretically lead to higher ferritin and lower TfR in these cells than in controls. However, the results showed that both ferritin and TfR are decreased, apparently through two different mechanisms. A lower ferritin level in cytoplasm was due to the decreased mRNA in the arsenite-transformed HOS cells, while the decline in TfR was due to a lowered IRP-binding activity. By challenging cells with iron, it was further established that arsenite-transformed HOS cells are less responsive to iron treatment than control HOS cells, which allows accumulation of iron in the transformed cells, as exemplified by significantly lower ferritin induction. On the other hand, caffeic acid phenethyl ester (CAPE), an antioxidant previously shown to suppress As-mediated cell transformation, prevents As-mediated ferritin depletion. In conclusion, our results suggest that altered iron homeostasis contributes to arsenite-induced oxidative stress and, thus, may be involved in arsenite-mediated cell transformation.

Antioxidants↗
PubMed2005

[Studies on the chemical constituents from herb of Rhodobryum roseum].

OBJECTIVE: To study the chemical constituents from herb of Rhodobryum roseum. METHOD: The compounds were isolated by column chromatography, and identified by IR, NMR data. RESULT: 8 compounds were isolated and identified. They are piperine (1), caffeic acid methyl ester (2), uracil glucoside (3), ursolic acid (4), 5alpha, 8alpha-epidioxy-methylcholesta-6, 22-dien-3beta-ol (5), 5alpha, 8alpha-epidioxy-methylcholesta-6,9(11), 22-trien-3beta-ol (6), beta-sitosterol (7), daucosterol (8). CONCLUSION: 7 compounds (1-6,8) were isolated from this plant for the first time.

Alkaloids↗
PubMed1991

Lipoxygenase-inhibitory action of antiviral polymeric oxidation products of polyphenols.

Various polymeric oxidation products of polyphenols strongly inhibited the purified lipoxygenase of rabbit reticulocytes, whereas the prostaglandin H synthase of sheep vesicular gland was only weakly inhibited. The oxidized polymeric preparations of caffeic acid, 2,5-dihydroxytoluene and 3,4-dihydroxytoluene were the most potent lipoxygenase inhibitors. Since such preparations are also known to inhibit herpes simplex virus in an early stage of the virus-cell interaction it is proposed that lipoxygenase metabolites are involved in virus-induced changes in the cell metabolism.

Animals↗
PubMed1993

[Separation and quantitative determination of seven aqueous depsides in Salvia miltiorrhiza by HPTLC scanning].

A new analytical method for the separation and determination of seven aqueous depsides in salvia miltiorrhiza by HPTLC has been developed. The seven depsides are protocatechualdehyde, caffeic acid, methyl rosmarinate, rosmarinic acid, salvianolic acid A, B and C. Using chloroform-ethyl acetate-benzene-formic acid(2.4:2:1:0.6) as developing solvent A, protocatechualdehyde was separated; using chloroform-ethyl acetate-benzene-formic acid-methanol (1.5:2:1:1:0.1) as developing solvent B, the other six constituents were well separated. The aqueous depsides were detected at the wave lengths of lambda S = 300 nm and lambda R = 240. This method is simple, rapid, sensitive and accurate. The contents of seven depsides in several Salvia species were determined.

Benzaldehydes↗
PubMed2005

Plant-derived anti-inflammatory compounds affect MIF tautomerase activity.

The cytokine macrophage migration inhibitory factor (MIF) has recently emerged as a crucial factor in the pathogenesis of rheumatoid arthritis (RA). It is debated whether the MIF mediated tautomeric conversion of either phenylpyruvate or of its other phenolic substrates is implicated in the pro-inflammatory action of this cytokine. Traditional herbal remedies have been used for centuries to alleviate inflammatory ailments of many kinds including arthritis. Several of their active ingredients identified are mono- or poly-phenol derivatives. In the present study the effect of some anti-inflammatory plant phenols on MIF mediated tautomerism of phenylpyruvate was investigated. Curcumin and caffeic acid were found to be the most potent inhibitors, exhibiting IC(50) values in the submicromolar range in the ketonase assay. Resveratrol and umbelliferon were almost as potent inhibitors as the antipyretic-analgetic drug acetaminophen. Our results reveal MIF as a possible target for the herbal anti-rheumatic agents.

Animals↗
PubMed1985

New lipoxygenase inhibitors isolated from Chinese plants. Development of new anti-allergic drugs.

Some natural compounds isolated from Chinese plants were found to have strong inhibitory activity for 5-lipoxygenase and were thus able to inhibit leucotriene synthesis. Among these compounds, caffeic acid was selected for study; more than 100 of its derivatives were synthesized and tested for 5-lipoxygenase inhibitory activity. Two derivatives, TMK-919 and TMK-920, proved to be 100 times more potent than the parent compound and were able to inhibit the homologous PCA reaction significantly in rats at a dose of 10 mg/kg, i.v.

Animals↗
PubMed1995

Interaction of 3'-O-caffeoyl D-quinic acid with human serum albumin.

The interaction of chlorogenic acid (CGA) with human serum albumin (HSA) was studied from the view-point of thermodynamics and mechanism of binding at pH 6.0. The association constants (Ka) for the HSA-CGA interaction at 10, 25 and 40 degrees C were 6.0 x 10(4), 9.0 x 10(3) and 2 x 10(4) M-1, resulting in delta G of -6.21, -5.80, -6.32 kcal/mol, respectively. These high Ka-values showed that the interaction between CGA and HSA is strong, endothermic and entropically driven. Binding of chlorogenic acid induces conformational change in HSA as indicated by quenching of fluorescence emission intensity along with a red shift in the emission maxima from 338 to 350 nm. This suggested the involvement of the lone tryptophan residue in the region of binding. Far-ultraviolet circular dichroic data showed a decrease in the alpha-helical content of HSA from 56 to 50% upon binding of CGA. These data are also supported by the decrease in the apparent Tm of HSA by 4 degrees C upon binding of CGA causing destabilization of the HSA molecule. The kinetics of the interaction involves a single step in the binding, and the kinetic curve attains equilibrium within 180 +/- 5 s. Data on caffeic acid (CA) and quinic acid (QA), which are the hydrolysis products of the bidentate CGA molecule, indicate that CA interacts more strongly than CGA. CA binds with an association constant of 8 x 10(4) M-1 and with a maximum number of binding sites of four. Microcalorimetric investigation of the interaction of these ligands with HSA suggests that the strength of binding follows the order CA >> CGA >>> QA with a single class of binding sites. The effect of temperature on the binding of CGA to HSA showed that the interaction is dominated by hydrophobic forces and hydrogen bonding.

Binding Sites↗
PubMed2002

Polyphenols from alcoholic apple cider are absorbed, metabolized and excreted by humans.

We determined the uptake and excretion of low doses of polyphenols in six subjects who each consumed 1.1 L of an alcoholic cider beverage. Over a 24-h period, no phloretin was detected in plasma (detection limit = 0.036 micromol/L), but 21 +/- 5% of the dose (4.8 mg) was excreted in the urine. In contrast, from a low dose of 1.6-mg quercetin equivalents, no quercetin was found in urine or plasma, but 3'-methyl quercetin was detected in plasma [C(max) (maximum concentration) = 0.14 +/- 0.19 micromol/L; range: 0 to 0.44 micromol/L]. No flavanol monomers (dose of free (+)-catechin and (-)-epicatechin = 3.5 mg) were detected in urine or plasma (detection limit: 0.01 micromol/L). Caffeic acid (total dose including esters = 11 mg) was detected only in plasma within 2 h, with C(max) = 0.43 +/- 0.3 micromol/L (range: 0.18 to 0.84 micromol/L). An almost 3-fold increase in hippuric acid was detected in 24-h urine (74 +/- 29 micromol/L; range: 38-116 micromol/L), compared with a prestudy value of 19 +/- 9 micromol/L. These data show that polyphenols are taken up from cider, that phloretin is excreted in the urine and suggest that low doses of quercetin are extensively methylated in humans.

Absorption↗
PubMed2005

[Study on the chemical constituents in roots and rhizomes of Ligularia duciforms].

OBJECTIVE: To study the chemical constituents in roots and rhizomes of ligularia duciforms. METHOD: The compounds were isolated by column chromatography, the structures were identified by physicochemical properties and spectral analysis. RESULT: Six compounds were isolated and identified as caffeic acid (I), (E)-docosyl-3, 4-dihydroxycinnamate (II), (E)-docosyl 3-methoxy-4-hydroxyferulate (III, beta-amyrone (IV), beta-sitosterol (V), and daucosterol (VI). CONCLUSION: All the compound were isolated for the first time from the plant, and the compound II and IV were isolated firstly from the genus Ligularia.

Asteraceae↗