Plasma levels of caffeic acid and antioxidant status after red wine intake

The aim of this study was to evaluate the bioavailability of caffeic acid and the modification of plasma antioxidant status following red wine intake. Five healthy male volunteers consumed 100, 200, and 300 mL of red wine corresponding to approximately 0.9, 1.8, and 2.7 mg of caffeic acid, respectively. Plasma samples collected at different times (0-300 min) were evaluated for their content of caffeic acid and their total antioxidant status. Both these parameters, i.e., plasma concentration of caffeic acid and antioxidant potential, were dose-dependent and the C(max) was reached at about 60 min after red wine intake. The results indicate that caffeic acid is bioavailable and it may be correlated with the antioxidant potential of plasma.

Comparative evaluation of St. John's wort from different Italian regions

Flowers and fruits of St. John's wort collected in different Italian regions were evaluated for their naphtodianthrone (hypericin and pseudohypericin), phloroglucinol (hyperforin and adhyperforin) and flavonol (rutin, quercetin, quercitrin, isoquercitrin and hyperoside) content. The quantitative evaluation was performed by HPLC-DAD. The crude drug collected at the fruit ripening period had the highest content in phloroglucinols and the lowest level of both naphtodianthrones and flavonols. Phloroglucinols peaked in the samples collected in Puglia followed by Lombardia and Veneto, while hypericins and flavonols were highest in the samples harvested in Sardegna and Trentino.

Liquid chromatography/atmospheric pressure chemical ionization mass spectrometry of terpene lactones in plasma of volunteers dosed with Ginkgo biloba L. extracts

Liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI-ITMS) was applied to evaluate the levels of ginkgolides A and B and bilobalide in plasma of volunteers after administration of Ginkgo biloba extracts in free (Ginkgoselect) or phospholipid complex (Ginkgoselect Phytosome) forms, providing 9.6 mg of total terpene lactones. The maximum plasma concentrations, C(max), of total ginkgolides A, B and bilobalide were 85.0 and 181.8 microg/mL for Ginkgoselect and Ginkgoselect Phytosome, respectively. The C(max) values were reached at 120 min for the free form and at 180--240 min for the phospholipid complex form. In both cases, the mean elimination half-life of each terpene lactone was in the range 120--180 min. Due to its sensitivity (about 1 ng/mL) and specificity, LC/APCI-ITMS proved to be a very powerful tool for pharmacokinetic studies of these phytochemicals.

Electrospray characterization of selected medicinal plant extracts

Extracts of selected medicinal plants were examined by electrospray mass spectrometry (ESI-MS). This technique allowed identification of the main components of each extract, thereby providing a typical finger-print of the examined plants. More specifically, anthocyanins (Vaccinium myrtillus), isoflavones (Glycine max, soybean), flavonol-glycosides and terpenes (Ginkgo biloba), triterpenes (Centella asiatica), caffeoyl-quinic acids (Cynara scolymus, artichoke), ginsenosides (Panax ginseng), catechins (Camellia sinensis, green tea) and flavones and flavanones (Propolis) were detected rapidly at levels in the range of 0.1-1 microg/ml, using 0.2-1 mg/ml of each medicinal plant extract.

Polyphenol content and total antioxidant activity of vini novelli (young red wines)

Eight commercial Italian vini novelli (red wines prepared by carbonic maceration and supposed to be consumed within three months from their wine-making) were evaluated for their total antioxidant activity. The wines had an average total phenol content (1605.4 +/- 337.4 mg/L gallic acid equivalents) lower than that of wines prepared by traditional maceration and consumable after aging (2057. 3 +/- 524.0 mg/L gallic acid equivalents). The average flavanol content (424.7 +/- 121.3 mg/L catechin equivalents) and the total antioxidant activity (16.8 +/- 3.8 mmol/L Trolox equivalents) of vini novelli were higher than the corresponding values (382.7 +/- 174.5 mg/L catechin equivalents and 12.3 +/- 3.3 mmol/L Trolox equivalents) found for aged wines. Three couples of experimental wines were prepared from the same grapes by traditional or carbonic maceration. These wines showed a different phenolic pattern, anthocyanins being more abundant in vini novelli. However, the average total antioxidant activities of the wines were similar, suggesting that aging (and not the wine-making technique) is the main factor influencing the antioxidant activity of red wines.

Electrospray ionization mass spectrometry of synthetic oligonucleotides using 2-propanol and spermidine

Oligonucleotides have become widely used tools in molecular biology and molecular diagnostics. Their parallel synthesis in large numbers and the increasing interest in microarray technology has raised the requirement for fast and informative analytical tools for their quality control. A direct injection electrospray ionization mass spectrometry (ESI-MS) technique based on the use of aqueous 2-propanol as running eluent, and spermidine (or triethylamine) as DNA modifiers, has been applied to analyze a large set of samples (about 200 synthetic oligonucleotides) ranging from 5 to 15 kDa (17-51mers) with good results in terms of sensitivity, suppression of sodium adduct formation, and speed of analysis. Copyright 2000 John Wiley & Sons, Ltd.

High performance liquid chromatography/electrospray mass spectrometry of Hypericum perforatum extracts

Hypericum perforatum L. (St. John's Wort) is a widely distributed herbaceous perennial plant which has been well known as a medicinal plant since antiquity. In recent years, H. perforatum has received increasing attention for the treatment of depression and other neuralgic disorders. The main constituents of H. perforatum extract include flavonoids, naphthodianthrones, phloroglucinols, essential oils and xanthones. The present work reports the analysis of naphthodianthrones and phloroglucinols in H. perforatum extracts by means of high performance liquid chromatography (HPLC) coupled simultaneously to a diode array detector (DAD) and electrospray mass spectrometry (ESI-MS). Hypericin, pseudohypericin, hyperforin and adhyperforin were separated and identified on the base of their on-line UV and mass spectra. Quantitative analysis of hypericin derivatives in different extracts of H. perforatum using DAD and MS detectors was performed. In addition, direct infusion ESI-MS of H. perforatum extracts was applied to obtain rapid mass fingerprints of constituents present in the sample.

Liquid chromatography/electrospray mass spectrometry of bioactive terpenoids in Ginkgo biloba L

Standardized extracts of Ginkgo biloba leaves are mainly used in the treatment of peripheral and celebral circulation disorders, and also as a remedy against asthma, coughs, bladder inflammation, blenorrhagia and alcohol abuse. The leaf extracts contain biflavones, flavonol glycosides and terpene lactones. This paper reports a method based on liquid chromatography coupled with electrospray mass spectrometry for the analysis of terpenoids in G. biloba extracts. This method allows the rapid isocratic separation of underivatized ginkgolides (GA, GB, GC and GJ) and bilobalide at very low levels (10 pg on the column) and their quantitative detection by external standardization with relative standard deviations of 3 and 5% for intra- and inter-day analyses, respectively.

Relationship between rate and extent of catechin absorption and plasma antioxidant status

Flavonoids are described to exert a large array of biological activities, which are mostly ascribed to their radical-scavenging, metal chelating and enzyme modulation ability. Most of these evidences have been obtained by in vitro studies on individual compounds and at doses largely exceeding those dietary. Little is known about a possible relationship between rate and extent of the absorption and modifications of plasma antioxidants. To elucidate this aspect, human volunteers were supplemented with single doses of green tea catechins in free (Greenselect) or phospholipid complex form (Greenselect Phytosome) equivalent to 400 mg epigallocatechingallate (EGCg). EGCg was chosen as biomarker for green tea catechin absorption, and its time course plasma concentration was correlated to the subsequent percent variations of plasma ascorbate, total glutathione, alpha-tocopherol, beta-carotene and Total Radical Antioxidant Parameter (TRAP). Green tea catechins were absorbed more extensively when administered as phospholipid complex rather than as free catechins. Single dose intake of both forms of catechins produced a transient decrease (10-20%) of plasma ascorbate and total glutathione and an increase of plasma TRAP (16-19%). These variations were consistent with the plasmatic levels of EGCg, ascorbate and total glutathione.

MEKC analysis of different Echinacea species

The distribution pattern of caffeic acid derivatives in Echinacea species is complex, and problems with the identity of each drug have been recognized. Micellar electrokinetic chromatography (MEKC) has been applied to define the fingerprints of Echinacea angustifolia, Echinacea pallida, and Echinacea purpurea, and their mixtures. The results obtained evidence that MEKC is a valuable tool for the characterization of these drugs.

Analytical strategies in the structural characterization of elcatonin

Elcatonin is a synthetic peptide of 32 amino acid residues, that differs from natural peptide hormone (eel calcitonin) in that the 1 and 7 cystine residues are replaced with alpha-amino suberic acid (Asu). Elcatonin is pharmacologically important, since it inhibits osteoclastic bone reserption and induces calcium uptake from body fluids. It is also used for the treatment of Page's disease and hypercalcemic conditions. Until now the structural characterization of elcatonin has been obtained by proteolytic digestion followed by high performance liquid chromatographic (HPLC) analysis of the peptide fragments. Capillary electrophoresis and fast-atom bombardment have also been employed. This work describes the results obtained when a liquid chromatograph, coupled to mass spectrometer using electrospray ionization (LC/ESI-MS) was applied to elcatonin analysis. After digestion with trypsin, the resulting peptides were separated by HPLC with 'on-line' UV detection, and directly injected into the ESI source. The molecular weights of all the fragments were detected, and the sequences of two of them were determined by collisionally induced dissociation in the ESI source. To confirm these 'on-line' results, the 'off-line' approach was also applied. In this case, the fragments from tryptic digestion were isolated by preparative HPLC, concentrated and analyzed by direct infusion into the ESI-MS system. Then, different elcatonin digests obtained using other proteases, e.g. protease V8 and clostripain, were analyzed by direct infusion, and these results combined with those achieved by the 'on-line' analysis allowed us to obtain the entire mapping of elcatonin.

Radical scavenger activity of three flavonoid metabolites studied by inhibition of chemiluminescence in human PMNs

3,4-Dihydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, and 3-(4-hydroxyphenyl)-propionic acid, metabolites which arise from quercetin glycosides, respectively, from flavones and probably from procyanidins by the human intestinal microflora, have been tested for their effects on oxygen radical production by human PMNs stimulated with FMLP or opsonized zymosan. Oxygen radicals were detected by luminol-augmented chemiluminescence measurements. Furthermore free radical scavenging activity of these metabolites was investigated in a cell-free system in which oxygen radicals were generated by horseradish peroxidase with H2O2 as substrate. 3,4-Dihydroxyphenylacetic acid reduced considerably chemiluminescence in PMNs in an amount which was much more pronounced than those of the other two metabolites. Concentrations of 1 mumol/l showed an inhibition by 84% with FMLP as stimulant and by 15% with opsonized zymosan, indicating that different signal transduction pathways are influenced in PMNs. Using the same conditions the unmetabolized quercetin showed an inhibition of chemiluminescence by 74% (FMLP), resp. 20% (opsonized zymosan). In the cell free system 3,4-dihydroxyphenylacetic acid suppressed much more effectively chemiluminescence than 3-hydroxyphenylacetic acid. In contrast, 3-(4-hydroxyphenyl)-propionic acid led to an increase of chemiluminescence generated in the cell-free system (FMLP and zymosan), i.e. by 30% by 25%, at the highest concentration of 4 mumol/l. In conclusion, flavonoid metabolites differ in their effects on free radical production of PMNs and their radical scavenging potencies.

Analysis of Stevia glycosides by capillary electrophoresis

The determination of diterpene glycosides from Stevia rebaudiana leaves using capillary electrophoresis is described. Analyses were performed on fused silica capillaries with 20 mM sodium tetraborate buffer, pH 8.3, and 30 mM sodium dodecyl sulfate. The effect of the organic solvent injected with the sample solution on the electrophoretic solution has been confirmed, and an absolute amount of 1.6 nL per injected sample was optimal. Rebaudioside A and steviolbioside were isolated by semipreparative high performance liquid chromatography (HPLC), and their structure was assessed by mass spectrometry.

Echinacoside and caffeoyl conjugates protect collagen from free radical-induced degradation: a potential use of Echinacea extracts in the prevention of skin photodamage

The protective effect of caffeoyl derivatives (echinacoside, chlorogenic acid, chicoric acid, cynarine, and caffeic acid, typical constituents of Echinacea species) on the free radical-induced degradation of Type III collagen has been investigated. The macromolecule was exposed to a flux of oxygen radicals (superoxide anion and hydroxyl radical) generated by the xanthine/xanthine oxidase/Fe2+/EDTA system and its degradation assessed qualitatively by SDS-PAGE and quantitatively as the amount of soluble peptides (according to the 4-hydroxyproline method) released from native collagen after oxidative stress. The SDS-PAGE pattern of native collagen is markedly modified by free radical attack, with formation of a great number of peptide fragments with molecular masses below 97 kDa: in the presence of microM concentrations of echinacoside, there is a complete recovery of the native profile. Collagen degradation was, in fact, dose-dependently inhibited by all the compounds, with the following order of potency: echinacoside approximately chicoric acid > cynarine approximately caffeic acid > chlorogenic acid, with IC50 ranging from 15 to 90 microM. These results indicate that this representative class of polyphenols of Echinacea species protects collagen from free radical damage through a scavenging effect on reactive oxygen species and/or C-, N-, S-centered secondary radicals, and provide an indication for the topical use of extracts from Echinacea species for the prevention/treatment of photodamage of the skin by UVA/UVB radiation, in which oxidative stress plays a crucial role.

Influence of structure on the behavior of flavonoids in capillary electrophoresis

In an attempt to elucidate the relation between structure and electrophoretic behavior, the effect of pH, surfactant and buffer on electrophoretic mobilities and resolution of several flavonoids, differing in structure, has been investigated. Ring-B substitution and the presence of a free hydroxy group at C7 of ring A play an important role, whereas O-methoxylation is less significant. Glycosylation also contributes in determining different degrees of complexation with borate, thus affecting the mobilities.

Improved procedure for the preparation of DNA restriction fragments suitable for sequencing

A rapid and integrated procedure was developed for the preparation of small DNA restriction fragments (< or = 1000 bp) starting from a large cosmid (35,000 bp) containing exogenous DNA. The process is based on restriction enzymatic digestion followed by HPLC separation and fractions collection. All DNA fragments are separated in a single run, detected "on-line" by UV absorption, and straightforward collected with very high recovery. Small fragments can be directly subjected to the sequence procedure, whereas those larger than 1000 bp are redigested with a second enzyme, the fractionated subfragments are separated, ligated to plasmid vector, and sequenced. A human genomic cosmid of 35,000 bp (26H7) has been chosen as a model.

Direct characterization of caffeoyl esters with antihyaluronidase activity in crude extracts from Echinacea angustifolia roots by fast atom bombardment tandem mass spectrometry

Fast atom bombardment (FAB-MS) and fast atom bombardment tandem mass spectrometry (FAB-MS/MS) techniques (negative ions) have been successfully applied for identification of the constituents responsible for the antihyaluronidase activity of Echinacea angustifolia roots, whose extracts are widely employed for the adjuvant therapy of chronic inflammatory diseases. Crude extracts from different solvents were tested for antihyaluronidase activity, and those with the greatest inhibitory action (the ethylacetate, butylacetate and chloroform fractions, IC50 0.44, 0.50 e 0.62 mg/ml) were directly analyzed by MS. Full scan mass spectra produced intense molecular anions: collisional activation of these resulted in tandem mass spectra rich in significant product ions. Four main caffeoyl conjugates were detected and identified by tandem mass spectrometry (daughter and parent ion mode): 2,3-O-dicaffeoyltartaric acid (chicoric acid) and 5-O-dicaffeoylquinic acid (cynarine) and 2-O-caffeoyltartaric acid (caffaric acid) in the ethylacetate fraction. Among these caffeoyl conjugates, chicoric and caftaric acids had the greatest antihyaluronidase activity: IC50 = 0.42 and 0.61 mM, while the IC50 of cynarine and chlorogenic acid were 1.85 and 2.25 mM.

Separation of flavonol-2-O-glycosides from Calendula officinalis and Sambucus nigra by high-performance liquid and micellar electrokinetic capillary chromatography

Calendula officinalis and Sambucus nigra flowers were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC) and micellar electrokinetic capillary chromatography (MECC). RP-HPLC was performed on C8 Aquapore RP 300 columns with eluents containing 2-propanol and tetrahydrofuran. MECC was carried out on a 72-cm fused-silica capillary using sodium dodecyl sulphate and sodium borate (pH 8.3) as the running buffer. The results obtained by these techniques are compared.

High-performance liquid chromatography determination of enzyme activities in the presence of small amounts of product

Enzymes can be assayed by HPLC by calculating the amount of substrate(s) left over, or product formed, through the peak area ratios with a suitable internal standard. However, sometimes the substrates used are contaminated with small amounts of products and this can lead to errors in the determination of the enzyme activity. A method for a HPLC test of such enzymes, which prevents eventual errors, uses the ratio substrate/product at time zero as internal standard and the kinetics can be followed with the aid of a simple mathematical equation. This approach was applied to the determination of the activities of papain, urokinase, NAD glycohydrolase, and pyruvate kinase samples and it was compared with the data obtained by the internal standard method, giving reproducible results in all cases.

Stable storage conditions of Immobiline chemicals for isoelectric focusing

Most of the problems connected with the use of the Immobiline chemicals (a set of six, non-amphoteric, acrylamido buffers having pK values in the pH 3.5-9.5 interval) can be attributed to the alkaline species (with pK values 6.2, 7.0, 8.5 and 9.3). These compounds, to varying degrees are subjected to two degradation pathways: (a) hydrolysis of the amido bond, producing free acrylic acid and a diamine, the latter unable to be incorporated into the polyacrylamide matrix; (b) spontaneous auto-polymerization, producing a number of oligomers up to n-mers, able to aggregate and precipitate large proteins. Storage of their water solutions as frozen aliquots, a method widely employed, only partially alleviates the problem. Addition of trace-amounts of inhibitors, as lately adopted by the manufacturer, could only reduce the problem of auto-polymerization, but not block the hydrolysis of the amido bond. A new solution has been found, which abolishes both phenomena: storage in n-propanol. As demonstrated by gas chromatography, HPLC analyses and two-dimensional separations of complex samples, storage in organic solvent completely abolishes both hydrolysis and auto-polymerization and allows production of highly reproducible focusing patterns.

High-performance liquid chromatographic assay of serotonin in human plasma

A sensitive and reproducible reversed-phase high-performance liquid chromatography with electrochemical detection for determination of serotonin in human plasma is described. The method has an average coefficient of variation of 3.5%; the recovery of serotonin and 5-hydroxy-N-methyltryptamine (internal standard) accounts for 95 +/- 2%. Average serotonin concentrations in platelet-free plasma and in platelet-rich plasma from 21 normal subjects 22-63-year-old) ranged from 0.6 to 4.9 ng/ml (mean 2.8 +/- 1.3 SD) and from 38.3 to 106.5 ng/10(8) platelets (mean 66.8 +/- 18.9 SD), respectively. The release of endogenous serotonin from human aggregating platelets challenged by collagen or adenosine diphosphate has been quantitated.

High-performance liquid chromatography for assaying NAD glycohydrolase from Neurospora crassa conidia

A rapid and sensitive high-performance liquid chromatographic technique was developed to determinate NAD glycohydrolase (EC 3.2.2.5.) activity from Neurospora crassa conidia. The separation of the assay substrate and products was achieved by isocratic reverse-phase chromatography and the peaks were detected by the absorbance at 259 nm. Quantities of NAD+ and nicotinamide as small as 10 pmol could be measured.