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Aging-associated up-regulation of neuronal 5-lipoxygenase expression: putative role in neuronal vulnerability.

Aging is associated with neurodegenerative processes. 5-Lipoxygenase (5-LO), which is also expressed in neurons, is the key enzyme in the synthesis of leukotrienes, inflammatory eicosanoids that are capable of promoting neurodegeneration. We hypothesized that neuronal 5-LO expression can be up-regulated in aging and that this may increase the brain's vulnerability to neurodegeneration. We observed differences in the distribution of 5-LO-like immunoreactivity in various brain areas of adult young (2-month-old) vs. old (24-month-old) male rats. Greater 5-LO-like immunoreactivity was found in old vs. young rats, in particular in the dendrites of pyramidal neurons in limbic structures, including the hippocampus, and in layer V pyramidal cells of the frontoparietal cortex and their apical dendrites. The aging-increased expression of neuronal 5-LO protein appears to be due to increased 5-LO gene expression. Using a quantitative reverse transcription/polymerase chain reaction assay and 5-LO-specific oligonucleotide primers and their mutated internal standards, we observed about a 2.5-fold greater hippocampal 5-LO mRNA content in old rats. 5-LO-like immunoreactivity was also observed in small, nonpyramidal cells, which were positive for glutamic acid decarboxylase or glial fibrillary acid protein. This type of 5-LO immunostaining did not increase in the old rats. Hippocampal excitotoxic injury induced by systemic injection of kainate was greater in old rats. Neuroprotection was observed with the 5-LO inhibitor, caffeic acid. Together, these results suggest that aging increases both neuronal 5-LO expression and neuronal vulnerability to 5-LO inhibitor-sensitive excitotoxicity, and indicate that the 5-LO system might play a significant role in the pathobiology of aging-associated neurodegenerative diseases.

Aging↗

Role of NADPH oxidase-mediated generation of reactive oxygen species in the mechanism of apoptosis induced by phenolic acids in HepG2 human hepatoma cells.

Although plant-derived phenolic acids have been reported to have anti-cancer activity, the exact mechanism is not completely understood. In this study, we investigated the role for reactive oxygen species (ROS) as a mediator of the apoptosis induced by caffeic acid (CA) and ferulic acid (FA), common phenolic acids in plants, in HepG2 human hepatoma cells. CA and FA reduced cell viability, and induced apoptotic cell death in a dose-dependent manner. In addition, they evoked a dose-related elevation of intracellular ROS. Treatment with various inhibitors of NADPH oxidase (diphenylene iodonium, apocynin, neopterine) significantly blunted both the generation of ROS and the induction of apoptosis induced by CA and FA. These results suggest that ROS generated through activation of NADPH oxidase may play an essential role in the apoptosis induced by CA and FA in HepG2 cells. These results further suggest that CA and FA may be valuable for the therapeutic management of human hepatomas.

Acetophenones↗

Antiinflammatory activity of extracts and fractions from the leaves of Gochnatia polymorpha.

The aqueous and ethanol extracts from the leaves of Gochnatia polymorpha and further fractions obtained from the latter extract using solvents with increasing polarity, including its aqueous residue and the amino acid, 4-hydroxy-N-methyl-proline were investigated by carrageenin-induced pedal oedema formation. It was shown that the aqueous and ethanol extracts and the ethyl acetate fraction demonstrated significant antiinflammatory activity. The chemical investigation of the latter fraction revealed the presence of caffeic acid, chlorogenic acid, 3-0-methylquercetin, hyperosid and rutin. The amino acid 4-hydroxy-N-methyl-proline, a nonprotein amino acid that has not been reported before in the Asteraceae was isolated as a major compound and identified by spectroscopic methods.

Analgesics↗

Synthesis and free radical scavenging activity of a novel metabolite from the fungus Colletotrichum gloeosporioides.

A novel metabolite (-)-1 was isolated as its peracetylated derivative, (-)-2-(3',4'-diacetoxyphenyl)-3,4-diacetoxytetrahydrofuran (2), from a strain of the phytopathogenic fungus Colletotrichum gloeosporioides CECT 20122. The synthesis of (-)-1 was carried out by ring-closing metathesis of diene 6 and stereoselective dihydroxylation of a dihydrofuran derivative 7 as key steps. The tetraol (-)-1 showed free radical scavenging activity comparable to that of BHT, caffeic acid or protocatechuic acid.

Acetates↗

Substrate specificity of the nateglinide/H(+) cotransport system for phenolic acids.

In clinical, patients usually take many kinds of drugs at the same time. Thus, drug-drug interactions involving transporters can often directly affect the therapeutic safety and efficacy of many important drugs. However, there have been few studies on food-drug interactions involving transporters. Dietary polyphenols have been widely assumed to be beneficial for human health. Polyphenols are found ubiquitously, and they are commercially prepared and used as functional foods. We have reported that ferulic acid, which is one of the most well-known polyphenols and is used as a functional food, affected the transport of nateglinide, an antidiabetic drug, by Caco-2 cells. In this study, we investigated the effects of other polyphenols on the nateglinide/H(+) transport system. We report here that caffeic acid and p-coumaric acid have a different inhibitory manner on the uptake of nateglinide. The results of this study are useful to identify the substrate specificity of the nateglinide/H(+) cotransporter.

Biological Transport↗

Acute regulation of glucose transport in a human megakaryocytic cell line: difference between growth factors and H(2)O(2).

The present study was undertaken to: (i) compare the effect of some hematopoietic growth factors, like interleukine-3, thrombopoietin, granulocyte-megakaryocyte colony-stimulating factor, stem cell factor, and reactive oxygen species such as H(2)O(2) on glucose uptake in a human leukemic megakaryocytic cell line, M07; (ii) investigate the changes in kinetic parameters of the transport activity induced by these stimuli; and (iii) evaluate the effect of genistein, a tyrosine kinase inhibitor, on the glucose uptake activation by the cited agents. The results are as follows: (i) exposure of M07 cells to thrombopoietin, granulocyte-megakaryocyte colony-stimulating factor, and stem cell factor resulted in a rapid stimulation of glucose transport; interleukine-3-treated cells exhibited no increase in the rate of glucose uptake, although M07 proliferation is interleukine-3 dependent; a rapid glucose transport enhancement was also observed when M07 cells were exposed to low doses of H(2)O(2); (ii) the transport kinetic parameters point out that an important difference exists between the effect of cytokines and that of H(2)O(2): cytokines increased predominantly the affinity for glucose, while H(2)O(2) raised both the V(max) and K(m) values; (iii) the isoflavone genistein, at a very low concentration, inhibited the stem cell factor- or H(2)O(2)-induced stimulation of hexose transport, reversing the variations of K(m) and V(max), but it did not affect the transport activity of granulocyte-megakaryocyte colony-stimulating factor-treated cells; and (iv) catalase completely abolished the stimulatory action of H(2)O(2) on glucose transport and slightly prevented the effect of stem cell factor, while caffeic acid phenethyl ester was only able to affect the activation due to stem cell factor.

Caffeic Acids↗

Antiviral activity of characterized extracts from echinacea spp. (Heliantheae: Asteraceae) against herpes simplex virus (HSV-I).

Extracts of 8 taxa of the genus Echinacea were found to have antiviral activity against Herpes simplex (HSV) virus Type I in vitro when exposed to visible and UV-A light. n-Hexane extracts of roots containing alkenes and amides were more active in general than ethyl acetate extracts containing caffeic acids. The most potent inhibitors of HSV were E. pallida var. sanguinea crude (70 % ethanol) inflorescence extract (MIC = 0.026 mg/mL), cichoric acid (MIC = 0.045 mg/mL) and Echinacea purpurea n-hexane root extract (MIC = 0.12 mg/mL).

Animals↗

[Studies on chemical constituents in dried buds of Lonicera similis Hemsl].

OBJECTIVE: To study the chemical constituents in the dried buds of Lonicera similis. METHOD: Chromatography and spectral analysis were used to isolate and elucidate the constituents. RESULT: Nine compounds were isolated from the dried buds of L. similis, and identified as caffeic acid; 3,5-O-dicaffeoylquinic acid; chlorogenic acid; palmitic acid; luteolin; quercetin; beta-sitosterol; nonacosanol; nonacosane. CONCLUSION: All the compounds were isolated from the plant for the first time.

Caffeic Acids↗

[Studies on the chemical constituents in herbs of Hemistepta lyrata].

OBJECTIVE: To investigate the chemical constituents of Hemistepta lyrata. METHOD: The constituents of the EtOAc-soluble portions of the 95% ethanol extract were isolated and purified by means of chromatography. Compounds were identified by their physical characteristics and spectral features. RESULT: Five compounds were isolated and identified as caffeic acid (1), tracheloside (2), uracil (3), 8-carboxymethyl-p-hydroxycinnamic acid (4), and 3-O-p-coumaroylquinic acid (5). CONCLUSION: Compounds 1-5 were isolated from this genus for the first time.

4-Butyrolactone↗

Effects of benzyl glucoside and chlorogenic acid from Prunus mume on adrenocorticotropic hormone (ACTH) and catecholamine levels in plasma of experimental menopausal model rats.

To investigate the effectiveness of benzyl beta-D-glucopyranoside (BG) and chlorogenic acid (CA), the constituents of the fruit of Prunus mume, for relieving tension in experimental menopausal model rats (M-rats) caused by ether stress, the effects of BG and CA on adrenocorticotropic hormone (ACTH) and catecholamine (adrenaline, noradrenaline, and dopamine) levels were examined in the plasma of M-rats. Caffeic acid, quinic acid, and rosmarinic acid, which are compounds structurally related to CA, were also examined. BG obviously recovered catecholamine levels decreased by ether stress and increased dopamine to high levels. On the other hand, CA significantly decreased the ACTH level increased by ether stress and showed the greatest effect of all compounds. These results suggest that BG and CA may contribute to relieving the tension in M-rats caused by ether stress.

Adrenocorticotropic Hormone↗

Metabolic studies on the total phenolic acids from the roots of Salvia miltiorrhiza in rats.

Phenolic acids are the main active constituents of Salvia miltiorrhiza Bunge. The metabolism of total phenolic acids from the roots of Salvia miltiorrhiza in rats was investigated. A sample preparation method combining the solid-phase extraction with liquid-liquid extraction was established to separate metabolites from the biological matrix. HPLC-UV and HPLC-MS methods were employed to analyze the metabolites. Five metabolites (M1-M5) were identified by HPLC-MS analysis and comparison with those of the reference standards. The fi ve metabolites were characterized as danshensu (M1), caffeic acid (M2), ferulic acid (M3), isoferulic acid (M4) and methylized ferulic acid (M5), respectively. The possible metabolic pathway of the phenolic acids is proposed.

Animals↗

[Chemical constituents of Conyza blinii Lévl].

Five compounds were isolated from the aerial part of Conyza blinii. On the basis of physicochemical properties and spectroscopic analysis, they were identified as alpha-spinasterol, 5, 8-dihydroxy-7, 3', 4'-trimethoxyflavone, caffeic acid, quercetin and syringic acid. All these compounds were isolated from the plant of C. blinii for the first time.

Asteraceae↗

Antioxidant phenolic glycosides from Moricandia arvensis.

The new phenolic glycosides quercetin 3,4'-di-O-beta-d-glucopyranoside-7-O-alpha-l-rhamnopyranoside (moricandin) (1), beta-d-glucopyranosyl 4-O-beta-d-glucopyranosylcaffeate (2), methyl 3-O-beta-d-glucopyranosyl-5-hydroxycinnamate (3), and beta-d-glucopyranosyl 4-O-beta-d-glucopyranosylbenzoate (4), together with the previously known beta-d-glucopyranosyl 4-hydroxybenzoate (5), methyl 4-O-beta-d-glucopyranosylcaffeate (6), 1-O-caffeoyl-beta-d-glucopyranoside (7), and 2-phenylethyl-beta-d-glucopyranoside (8), were isolated from the flowers of Moricandia arvensis. Their structures were elucidated by extensive spectroscopic analysis and chemical methods. Compounds 1-8 were evaluated for antioxidant activity using DPPH, TEAC, and reducing power assays, where the caffeic acid derivative 7 and the quercetin triglycoside 2 proved to possess the most potent scavenging activity.

Antioxidants↗

[V. The phenolics of strawberries and their changes during development and ripeness of the fruits (author's transl)].

16 strawberry varieties contained ca. 10--70 mg (+)-catechin per kg freshweight, frequently up to 10 mg (-)-epicatechin, seldom (+)-gallocatechin and never (-)-epigallocatechin. The phenolic contents after hydrolysis were up to ca. 10 mg caffeic acid, ca. 10--15 mg p-coumaric acid, ca. 10--35 mg 4-hydroxybenzoic acid, up to 6 mg protocatechuic acid and ca. 10--40 mg gallic acid per 1000 g freshweight. From "Senga Sengana" ca. 10 mg/kg methyl gallate and ellagic acid were isolated. Salicylic acid, gentisic acid and vanillic acid were found in traces (1 mg/kg). The concentrations of all the examined phenolic acids, relating to the whole fruit (mg per fruit) increased, and, relating to fresh weight (mg per kg) decreased during the growth of the fruits with exception of 4-hydroxybenzoic acid. This acid appeared only in a relatively late stage of the fruit. The changes in catechins were similar. In the ripe fruit the catechin level was reduced a little.

Benzopyrans↗

Phenolic compounds in seven South American Ilex species.

Ilex paraguariensis (common name: 'mate' or 'yerba mate') is used for the preparation of the most popular tea-like beverage of South America. Choleretic, hypocholesteremic, antioxidant, hepatoprotective and bitter taste properties of mate are attributed to the phenolic constituents of the leaves. I. paraguariensis has seven local congeneric substitutes or adulterants: I. brevicuspis; I. theezans; I. microdonta; I. dumosa var. dumosa; I. taubertiana; I. pseudobuxus; I. integerrima; and I. argentina. An HPLC method using UV with Photodiode Array Detector was developed for the identification and quantification of caffeoyl derivatives (caffeic acid, chlorogenic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid) and flavonoids (quercetin, rutin and kaempferol) in these species. I. paraguariensis showed a higher content of flavonoids and caffeoyl derivatives than the other assayed species.

Caffeic Acids↗

[Studies on chemical constituent of Solanum lyratum].

OBJECTIVE: To study chemical constituents of Solanum lyratum. METHOD: The constituens were isolated by polystyrene resin RA, sephadex LH-20 and silica gel column chormatography, their structures were identified by spectroscopic analysis. RESULT: Four compounds were identified as The constituens were caffeic acid, vanillic acid, rutin and N(p-hydropheneethyl) p-coumaramide. CONCLUSION: These compounds were isolated from this plant for the first time.

Caffeic Acids↗

Genotoxicity of instant coffee and of some phenolic compounds present in coffee upon nitrosation.

Instant coffee exhibits genotoxic activity upon nitrosation at acidic pH values in the Ames tester strain TA100. Using adsorption chromatography (Amberlit XAD-2) it was observed that the major fraction of molecules responsible for the genotoxic activity upon nitrosation was not retained on this resin, suggesting that the polar molecules present in instant coffee could be responsible for the genotoxicity observed upon nitrosation. Some phenolic molecules present in instant coffee (catechol, caffeic acid, and chlorogenic acid) were also genotoxic upon nitrosation under the same experimental conditions. The concentrations of nitrosatable phenolic compounds in the studied coffee were determined by HPLC and their contributions to the total genotoxicity observed were studied. The results obtained suggest that besides phenolic compounds other molecules were also involved in the genotoxicity of this beverage upon nitrosation. Teratogenesis Carcinog. Mutagen. 20:241-249, 2000.

Adsorption↗

Intracellular Ca2+ mediates lipoxygenase-induced proliferation of U-373 MG human astrocytoma cells.

The role of intracellular Ca2+ in the regulation of tumor cell proliferation by products of arachidonic acid (AA) metabolism was investigated using U-373 MG human astrocytoma cells. Treatment with nordihydroguaiaretic acid (NDGA), a lipoxygenase (LOX) inhibitor, or caffeic acid (CA), a specific 5-LOX inhibitor, suppressed proliferation of the tumor cells in a dose-dependent manner. However, indomethacin (Indo), a cyclooxygenase (COX) inhibitor, did not significantly alter proliferation of the tumor cells. At anti-proliferative concentrations, NDGA and CA significantly inhibited intracellular Ca2+ release induced by carbachol, a known intracellular Ca2+ agonist in the tumor cells. Exogenous administration of leukotriene B4 (LTB4), an AA metabolite of LOX pathway, enhanced proliferation of the tumor cells in a concentration-dependent fashion. In addition, LTB4 induced intracellular Ca2+ release. Intracellular Ca2+ inhibitors, such as an intracellular Ca2+ chelator (BAPTA) and intracellular Ca(2+)-release inhibitors (dantrolene and TMB-8), significantly blocked the LTB4-induced enhancement of cell proliferation and intracellular Ca2+ release. These results suggest that LOX activity may be critical for cell proliferation of the human astrocytoma cells and that intracellular Ca2+ may play a major role in the mechanism of action of LOX.

Arachidonic Acid↗