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Dynamic ultrasound-assisted extraction of polyphenols in tobacco.

A novel extraction method, namely dynamic ultrasound-assisted extraction, is investigated. This technique is efficient with respect to both time and solvent consumption because it utilizes ultrasonic energy in dynamic mode during extraction. Polyphenols (chlorogenic acid, esculetin, rutin, scopoletin, and quercitrin) are extracted from a tobacco (Nicotina tobaccum L.) sample for 10 min with 6 mL of solvent. Fresh solvent is continuously pumped through the sample, with which the analytes can be rapidly extracted, and the possibility of degradation efficiently avoided. Methanol involving 0.5% w/v ascorbic acid was used as extraction solvent; optimal flow rate and extraction time were investigated. The extract was cleaned up by C18 disposable cartridge. The spiked and nonspiked tobacco samples were used for the evaluation of the proposed method. Recoveries obtained were varied from 96 to 108% and RSDs from 2.0 to 4.6%. This extraction technique was revealed to recover larger amounts of polyphenols from tobacco, compared to the static ultrasound-assisted extraction method.

Carbon↗

High-performance capillary electrophoresis analysis of mate infusions prepared from stems and leaves of Ilex paraguariensis using automated micellar electrokinetic capillary chromatography.

An automated micellar electrokinetic capillary chromatographic method has been developed in order to determine xanthines, e.g. caffeine, theobromine and theophylline, and chlorogenic acid in samples of yerba mate (Ilex paraguariensis). The target constituents were detected by photodiode array, and quantified by an external standard method. In addition, each constituent was collected separately and identified by EIMS. The method has been used to analyse 30 samples of mate infusions prepared at 30 and 75 degrees C with milled leaves and stems of 14 commercial brands which had been subjected to different elaboration processes. Suspended powdered material of each infusion was also analysed after three sieving steps. There was a remarkable difference in the relative xanthine composition of the finely suspended material, the amount of which varied according to the yerba mate brand, the elaboration process and the temperature of the infusion. The importance of these results with respect to gastrointestinal disorders which have been observed by habitual consumers of mate are discussed.

Automation↗

Identification of isomeric dicaffeoylquinic acids from Eleutherococcus senticosus using HPLC-ESI/TOF/MS and 1H-NMR methods.

Liquid chromatography-electrospray time-of-flight mass spectrometry (HPLC-ESI/TOF/MS) and a novel NMR technique, developed to maximise the sensitivity obtained from the standard NMR spectrometer, have been applied to the identification of the phenolic constituents of Eleutherococcus senticosus. In addition, molecular modelling and dihedral bond angle calculations based on the vicinal 3JHH-coupling constants have been used in the unambiguous assignment of signals in the 1H-NMR spectra. 5'-O-Caffeoylquinic acid and three isomeric compounds, 1',5'-O-dicaffeoylquinic acid, 3',5'-O-dicaffeoylquinic acid and 4',5'-O-dicaffeoylquinic acid, have been isolated and identified from a sample. The isolation and structure determination of the latter two compounds are reported for the first time from this plant.

Algorithms↗

Development of an HPLC-PAD-MS assay for the identification and quantification of major phenolic edelweiss (Leontopodium alpium Cass.) constituents.

The analytical assessment of edelweiss (Leontopodium alpinum) herb extracts, used in traditional alpine medicine, has resulted in the development of a HPLC-PAD-MS method that allows baseline separation of almost all constituents. Peak assignment of 14 analytes was achieved by comparison of retention times, UV and mass spectra with those of reference compounds either commercially available (luteolin, apigenin and chlorogenic acid) or isolated from edelweiss plants by column chromatography. Ten of the isolated analytes were identified as the known natural products: quercetin-3-O-beta-D-glucoside, luteolin-7-O-beta-D-glucoside, luteolin-3'-O-beta-D-glucoside, luteolin-4'-O-beta-D-glucoside, apigenin-7-O-beta-D-glucoside, 6-hydroxy-luteolin-7-O-beta-D-glucoside, luteolin-7,4'-di-O-beta-D-glucoside, chrysoeriol-7-O-beta-D-glucoside, leontopodic acid and 3,5-dicaffeolyquinic acid. One analyte, 3,4,5-tri-(E)-caffeoly-D-glucaric acid proved to be a new natural product and was named leontopodic acid B. Structure elucidation was carried out by means of MS and NMR spectroscopy in all cases. The aerial plant parts of L. alpinum (capitula, inflorescence leaves, stems, stem leaves and leaves of the basal rosette) showed variable amounts of the above-mentioned constituents, although qualitative differences were not observable.

Asteraceae↗

4-Coumaroyl coenzyme A 3-hydroxylase activity from cell cultures of Lithospermum erythrorhizon and its relationship to polyphenol oxidase.

A 4-coumaroyl-CoA 3-hydroxylase activity was purified 4600-fold from cell cultures of Lithospermum erythrorhizon. The enzyme showed a molecular mass of 42,400 +/- 1700 Da in gel chromatography and required ascorbate, NADH, or NADPH as cofactors. 4-Coumaroyl-CoA, 4-coumarate, p-cresol, and several other phenolic substances, but not tyrosine, were accepted as substrates for the hydroxylation. Besides hydroxylase activity, the enzyme showed diphenol oxidase activity. Both activities were inhibited by diethyldithiocarbamate or beta-mercaptoethanol, although at different concentrations. The enzyme showed striking similarity to a 4-coumaroyl-glucose 3-hydroxylase from sweet potato (Ipomoe batatas) roots, which has reportedly been purified to homogeneity and identified as a specific enzyme of chlorogenic acid biosynthesis. Close examination and comparison to a commercially available polyphenol oxidase, however, suggest that the enzyme activities purified from both Lithospermum and sweet potato are polyphenol oxidases rather than specific enzymes of secondary metabolism.

Adenine Nucleotides↗

Upregulation of hepatic glucose 6-phosphatase gene expression in rats treated with an inhibitor of glucose-6-phosphate translocase.

The multicomponent hepatic glucose 6-phosphatase (Glc-6-Pase) system catalyzes the terminal step of hepatic glucose production and plays a key role in the regulation of blood glucose. We used the chlorogenic acid derivative S 3483, a reversible inhibitor of the glucose-6-phosphate (Glc-6-P) translocase component, to demonstrate for the first time upregulation of Glc-6-Pase expression in rat liver in vivo after inhibition of Glc-6-P translocase. In accordance with its mode of action, S 3483-treatment of overnight-fasted rats induced hypoglycemia and increased blood lactate, hepatic Glc-6-P, and glycogen. The metabolic changes were accompanied by rapid and marked increases in Glc-6-Pase mRNA (above 35-fold), protein (about 2-fold), and enzymatic activity (about 2-fold). Maximal mRNA levels were reached after 4 h of treatment. Glycemia, blood lactate, and Glc-6-Pase mRNA levels returned to control values, whereas Glc-6-P and glycogen levels decreased but were still elevated 2 h after S 3483 withdrawal. The capacity for Glc-6-P influx was only marginally increased after 8.5 h of treatment. Prevention of hypoglycemia by euglycemic clamp did not abolish the increase in Glc-6-Pase mRNA induced by S 3483 treatment. A similar pattern of hypoglycemia and possibly of associated counterregulatory responses elicited by treatment with the phosphoenolpyruvate carboxykinase inhibitor 3-mercaptopicolinic acid could account for only a 2-fold induction of Glc-6-Pase mRNA. These findings suggest that the significant upregulation of Glc-6-Pase gene expression observed after treatment of rats in vivo with an inhibitor of Glc-6-P translocase is caused predominantly either by S 3483 per se or by the compound-induced changes of intracellular carbohydrate metabolism.

Animals↗

Bioavailability of ferulic acid.

There is a wealth of evidence for the powerful antioxidant properties in vitro of flavonoid components of the diet. However, few studies have been undertaken concerning the hydroxycinnamates, major constituents of fruit, some vegetables, beverages, and grains, particularly the extent to which they are absorbed in vivo from the diet. The study described here has investigated the bioavailability of ferulic acid in humans, from tomato consumption, through the monitoring of the pharmacokinetics of excretion in relation to intake. The results show that the peak time for maximal urinary excretion is approximately 7 h and the recovery of ferulic acid in the urine, on the basis of total free ferulic acid and feruloyl glucuronide excreted, is 11-25% of that ingested.

Adult↗

In Vitro Effects of Secondary Plant Compounds on Germination of Blastospores of the Entomopathogenic Fungus Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes)

Seven secondary plant compounds (catechol, chlorogenic acid, gallic acid, salicylic acid, saponin, sinigrin, and tannic acid) mixed with Noble agar at three concentrations (100, 500, and 1000 ppm) were tested for their effects on germination of blastospores of the fungal entomopathogen Paecilomyces fumosoroseus. With individual allelochemicals incorporated at 100 ppm in Noble agar, significant differences in time to 95% germination were found between two allelochemicals (catechol and salicylic acid) and the control. Blastospores in media containing 100 ppm catechol took twice as long (10 hr) to reach 95% germination as the control. Germination of blastospores in medium containing catechol, salicylic acid, or tannic acid at 500 was 55, 56, and 46%, respectively, in contrast to less than 10% when the concentration was 1000 ppm. These results indicate that the presence of allelochemicals on a substrate (e.g., insect cuticle or leaf) may be an additional constraint to the survival of entomopathogenic fungi. Copyright 1997 Academic Press. Copyright 1997 Academic Press

Journal Article↗

Antioxidative and protective properties of extracts from leaves of the artichoke (Cynara scolymus L.) against hydroperoxide-induced oxidative stress in cultured rat hepatocytes.

Primary rat hepatocyte cultures exposed to tert-butylhydroperoxide (t-BHP) or cumene hydroperoxide were used to assess the antioxidative and protective potential of water-soluble extracts of artichoke leaves. Both hydroperoxides stimulated the production of malondialdehyde (MDA), particularly when the cells were pretreated with diethylmaleate (DEM) in order to diminish the level of cellular glutathione (GSH). Addition of artichoke extracts did not affect basal MDA production, but prevented the hydroperoxide-induced increase of MDA formation in a concentration-dependent manner when presented simultaneously or prior to the peroxides. The effective concentrations (down to 0.001 mg/ml) were well below the cytotoxic levels of the extracts which started above 1 mg/ml. The protective potential assessed by the LDH leakage assay and the MTT assay closely paralleled the reduction in MDA production and largely prevented hepatocyte necrosis induced by the hydroperoxides. The artichoke extracts did not affect the cellular level of glutathione (GSH), but diminished the loss of total GSH and the cellular leakage of GSSG resulting from exposure to t-BHP. Chlorogenic acid and cynarin accounted for only part of the antioxidative principle of the extracts which was resistant against tryptic digestion, boiling, acidification, and other treatments, but was slightly sensitive to alkalinization. These results demonstrate that artichoke extracts have a marked antioxidative and protective potential. Primary hepatocyte cultures seem suitable for identifying the constituents responsible for these effects and for elucidating their possible mode of action.

Animals↗

Mycelial elongation and sporulation of two fungi on amended media in light or dark.

Botrytis allii and Collectotrichum dematium are onion pathogens which can infect in the field and cause decay in storage. Some phenolics can hinder development of these fungi, but the effect of cytokinins is not clear. Cytokinins (kinetin or 6-benzyladenine) or phenolics (caffeic or chlorogenic acids) were added to agar at concentrations of 0 to 10(-3) M. Cultures were continuously irradiated with fluorescent light or maintained in the dark for 6 days. On unamended media, final mycelial elongation was 45 or 17.8 mm and sporulation was 28 or 10.6 x 10(4) spores/ml for Botrytis and Colletotrichum, respectively. For Botrytis, mycelial elongation was slightly (5%) but significantly increased and sporulation increased by 21% by incubation on phenolics as compared to cytokinins. Mycelial extension of Colletotrichum was not affected by amendment. Sporulation of Colletotrichum on kinetin was 16 to 28% greater than on the other amendments. As amendments concentration increased elongation of mycelia of both fungi decreased. Sporulation of Botrytis increased by 60% as amendment concentration increased from 0 to 10(-5) M and then decreased 25% at 10(-3) M. As amendment concentration increased from 0 to 10(-3) M, sporulation of Colletotrichum increased by 45%. Incubation in light increased mycelial extension 3 to 17% for Botrytis and Colletotrichum respectively, and sporulation was increased approximately 78% for both fungi. These compounds do not appear to inhibit development of these Botrytis or Colletotrichum species in culture.

Culture Media↗

[Occurrence of phenols in coffee melanoidins].

Compounds with higher molecular weights in roast coffee were separated by means of adsorption chromatography followed by gel chromatography which yielded seven fractions of different molecular weights. These were tested sensorially and degraded by Curie point pyrolysis high-resolution gas chromatography/mass spectrometry (HRGC/MS) about 100 products, among them 33 phenols, were found. The products were compared with fragments formed via model pyrolysis experiments on chlorogenic acid.

Chromatography, Gel↗

Automated determination of total polyphenols in apple juice.

An automated method of total polyphenols analysis in apple juice using the Folin-Ciocalteu reagent is presented. Chlorogenic acid was selected as the standard since a similar kinetic behaviour, standard-sample, was observed. A straightforward method with good reproducibility (CV < 1%), sampling frequency (48 h-1) and correlation with the traditional batch method (r = 0.9924) is proposed.

Beverages↗

Fluorescence emission spectra of plant leaves and plant constituents.

The UV-B radiation (e.g. 337 nm) induced blue fluorescence (BF) and red chlorophyll fluorescence spectra (RF) of green leaves from plants with different leaf structure were determined and the possible nature and candidates of the blue fluorescence emission investigated. The blue fluorescence BF is characterized by a main maximum in the 450 nm region and in most cases by a second maximum/shoulder in the 530 nm region. The latter has been termed green fluorescence GF. The red chlorophyll fluorescence RF, in turn, exhibits two maxima in the 690 and 730 nm region. In general, the intensity of BF, GF and RF emission is significantly higher in the lower than the upper leaf side. The ratio of BF to RF emission (F450/F690) seems to vary from plant species to plant species. BF and GF emission spectra appear to be a mixed signal composed of the fluorescence emission of several substances of the plant vacuole and cell wall, which may primarily arise in the epidermis. Leaves with removed epidermis and chlorophyll-free leaves, however, still exhibit a BF and GF emission. Candidates for the blue fluorescence emission (lambda max near 450 nm) are phenolic substances such as chlorogenic acid, caffeic acid, coumarins (aesculetin, scopoletin), stilbenes (t-stilbene, rhaponticin), the spectra of which are shown. GF emission (lambda max near 530 nm) seems to be caused by substances like the alkaloid berberine and quercetin. Riboflavine, NADPH and phyllohydroquinone K1 seem to contribute little to the BF and GF emission as compared to the other plant compounds. Purified natural beta-carotene does not exhibit any blue fluorescence.

Chloroplasts↗

Genotoxic investigations of tobacco protein using microbial and mammalian test systems.

Tobacco protein was assayed for mutagenicity using the Ames test and three in vivo tests. In the Salmonella strains TA 98 and TA 100 methanolic extracts of the tobacco protein and urine of rats fed tobacco protein exhibited increased revertant numbers, but extracts of feces did not. Using the micronucleus test throughout, weak mutagenic effects after feeding the tobacco protein were detected in Chinese hamsters and two inbred strains of mice, and again in Chinese hamsters when the chromosome aberration test and the SCE test were applied. The analytical specifications of the tobacco protein listed nicotine, chlorogenic acid and rutin as components. These were examined separately in a chromosome aberration test, and nicotine was discovered to be the factor or a factor responsible for the weak positive test results.

Animals↗

[Coffee and health].

Coffee as a rule develops stimulating effects on the central nervous system, heart and circulation which are mainly caused by caffeine. In certain cases coffee may also have a sedative effect and sometimes even it is useful to fall asleep quickly. Furthermore coffee may be advantageous in the treatment of some functional disorders caused by lacking of dopamine, because coffee is able to increase the dopamine formation in brain. Concerning the effects of coffee in the gastrointestinal-tract and liver-bile system caffeine is only of secondary importance. Hereby certain roasting substances, possibly also chlorogenic acid or caffeic acid should be responsible for the stimulating effects observed in these organs. These stimulating effects could be caused whether directly or indirect e.g. by liberating gastrin or other gastrointestinal hormones. Vitamin niacin, which is formed in greater amounts from trigonelline during the roasting process, may also be important from the nutritional standpoint. Therefore coffee may be prescribed as a true drug in cases of deficiency in vitamin niacin or also in the pellagra disease. By extensive epidemiological studies performed lately it could be demonstrated that there exists no correlation between coffee consumption and certain risk factors as hypertension, heart infarction, diabetes, gout or cancer diseases. Furthermore there was no evidence that coffee or its caffeine content are able to induce genetic alterations or even malformations.

Animals↗

Identification and mapping of a major gene (Ft1) involved in fructification time in the interspecific cross Coffea pseudozanguebariae x C. liberica var. Dewevrei: impact on caffeine content and seed weight.

Fructification time was studied in the interspecific cross Coffea pseudozanguebariae x C. liberica var. Dewevrei (PSE x DEW). Parental species, F(1) hybrids and offspring of the first backcross generation (BC(1)), consisting of F(1) x PSE (BCPSE) and F(1) x DEW (BCDEW) plants, were observed. Fructification time can be split into two independent visual phases: the full-growth period, from blooming up to the end of fruit growth, and the maturation phase, defined by the green to red color change. Fructification time was found to be an additive trait. The full-growth period showed a bimodal distribution in the BCDEW hybrid, suggesting the involvement of Ft1, a major gene that was mapped on linkage group E. The main effects of Ft1 were to lower caffeine content and 100-seed weight, without any impact on chlorogenic acid, trigonelline and sucrose contents. Two molecular markers were identified that bracket Ft1 and which could be used for early marker-assisted selection.

Caffeine↗

4-Caffeoyl-1,5-quinide in roasted coffee inhibits [3H]naloxone binding and reverses anti-nociceptive effects of morphine in mice.

RATIONALE: Cinnamoylquinides are formed from the corresponding chlorogenic acids during coffee roasting. Instant coffee has been shown to displace binding of the mu opioid receptor antagonist, [3H]naloxone, but the putative active agent, feruloylquinide, has not been characterized. OBJECTIVES: The goal was to identify the active agent(s) in coffee by measuring the binding affinity of individual cinnamoyl-1,5-quinides to the human mu opioid receptor, and determine the effects of these compounds on morphine-induced anti-nociceptive behavior in mice. METHODS: Cinnamoyl-1,5-quinides in extracts of decaffeinated instant coffee were quantified by reverse-phase HPLC comparisons with synthetic samples of 3-coumaroyl-1,5-quinide and 4-coumaroyl-1,5-quinide, 3-caffeoyl-1,5-quinide and 4-caffeoyl-1,5-quinide (4-CQL) 3-feruloyl-1,5-quinide and 4-feruloyl-1,5-quinides and 3,4-dicaffeoyl-1,5-quinide (DICAQ). Affinities of the cinnamoyl-1,5-quinides and decaffeinated instant coffee extract were determined by displacement of [3H]naloxone binding in cultured HEK-MOR cells. Inhibition of the anti-nociceptive activity of morphine (1 mg/kg IP) was determined in C57BL/6J mice using the hot plate test at 52 degrees C. RESULTS: Extract of decaffeinated instant coffee produced a displacement K(i) of 42+/-16 mg/l, while the K(i) of a synthetic sample of 4-CQL was 4.4+/-0.4 microM. Compounds with a cinnamoyl substituent in the 4-position of the quinide, i.e. 4-CQL, DICAQ, 3,4-diferuloyl-1,5-quinide, and 3,4-dicoumaroyl-1,5-quinide, had affinities for the mu opioid receptor in the low micromolar range. In the hot plate test, coffee extract, containing 0.78% of 4-CQL, reversed the anti-nociceptive effect of morphine at 10 mg/kg IP. Two cinnamoyl-1,5-quinides found in roasted coffee, DICAQ, and 4-CQL, were active at 1 and 0.1 mg/kg IP, respectively. CONCLUSIONS: These results suggest that the previously reported anti-opioid activity of instant coffee is caused primarily by the presence of 4-CQL, and to lesser extent by other cinnamoyl-1,5-quinides.

Analgesics, Opioid↗