Offline derivatization LC-MS/MS method for simultaneous estimation of vanillin and vanillic acid in guinea pig plasma.

AIM: Vanillin used as a positive control substrate of aldehyde oxidase activity gets metabolized to vanillic acid. Low MW and low sensitivity in negative ion mode are challenges with these analytes. Our objective was to develop a simple offline derivatization LC-MS/MS method to address these challenges. METHODOLOGY/RESULTS: A simple dansyl chloride derivatization of the phenolic groups on vanillin and vanillic acid was adopted to enable easy ionization in commonly used acidic mobile phases. Calibration curves were linear over the concentrations of 4.88-1250 nM with an LLOQ of 0.64 fmoles on column for both analytes. CONCLUSION: The qualified method was successfully applied to simultaneously measure vanillin and vanillic acid in plasma and urine from a guinea pig pharmacokinetic study.

Metabolic profiling of phenolic acids and oxidative stress markers after consumption of Lonicera caerulea L. fruit.

This study investigated the effect of one-week consumption of 165 g/day fresh blue honeysuckle berries (208 mg/day anthocyanins) in 10 healthy volunteers. At the end of intervention, levels of benzoic (median 1782 vs 4156), protocatechuic (709 vs 2417), vanillic (2779 vs 4753), 3-hydroxycinnamic (143 vs 351), p-coumaric (182 vs 271), isoferulic (805 vs 1570), ferulic (1086 vs 2395), and hippuric (194833 vs 398711 µg/mg creatinine) acids by LC/MS were significantly increased in the urine. Clinical chemistry safety markers were not altered. Oxidative stress markers, erythrocyte glutathione peroxidase (0.73 vs 0.88 U/g Hb) and catalase (2.5 vs 2.8 µkat/g Hb) activities, and erythrocyte/plasma thiobarbituric acid reactive substance (522 vs 612/33 vs 38 µmol/g Hb/protein) levels were significantly increased, without change in plasma antioxidant status. Nonsignificant changes of advanced oxidation protein products and oxidized LDL were observed. The results provide a solid base for further study of metabolite excretion and antioxidant parameters after ingestion of anthocyanins.

[The HPLC analysis of vanillil-almond, 5-hydroxiindolacetic, homovanillic and homogentisic acids in biologic fluids in clinical laboratory].

The simple and fast HPLC technique of analysis of vanillil-almond, 5-hydroxiindolacetic, homovanillic and homogentisic acids in urine with solid-phase extraction using ultra cross-linked polystyrene (Purosep-200) is proposed. The separation on column Chromolith Performance RP-18e "Merck" 100x4.6 mm with monolithic phase-reversed silica gel in isocratic or gradient mode with ultraviolet detection under 285 nm. The isocratic mode is applied in case of ordinary analysis of vanillil-almond or homogentisic acids. The composition of eluent is isopropanol - water - TFA (1:99:0.025, v/v/v), flow speed is 1400 mkl/min; pressure is 37 bar, full separation less than in 4 min. The gradient low pressure mode is applied to analyze vanillil-almond, hydroxiindolacetic and homovanillic acids. Under this approach the switching to second eluent occurred from second minute. The composition of eluent is isopropanol-water-TFA (6:94:0.025, v/v/v), flow speed is 1400 mkl/min, pressure is 43 bar, full separation is less than in 7 min. The output (extraction share) consisted 78-113%. The simplicity reproducibility and sufficient sensitivity of technique in combination with the possibility of its application on standard chromatographic equipment (isocratic pump and ultraviolet detector) made it useful for routine clinical application.

Inhibitory effects of urinary metabolites on platelet aggregation after orally administering Shimotsu-To, a traditional Chinese medicine, to rats.

Shimotsu-To, which consists of four herbal extracts, has been used clinically for improving abnormal blood coagulation, fibrinolysis, atherosclerosis and chronic inflammation in Japan and China. We have investigated the pharmacological relationship between the effects and chemical components of Shimotsu-To after oral administration to rats. The urinary constituents were separated and identified by three dimensional (3D-) HPLC equipped with a photodiode array detector as a new tool and the chemical structures were determined by spectroscopic methods to be trans-ferulic acid-3-O-sulfate (1), vanillic acid (2), m-hydroxyphenylpropionic acid (3), trans-ferulic acid (4) and cis-ferulic acid (5). Of these compounds, 2-5 strongly inhibited platelet aggregation induced by ADP and arachidonic acid. Compound 1, the sulfate conjugate of 4, did not show any inhibitory effect, which suggested that the inhibitory effect on platelet aggregation was inactivated by sulfate conjugation. These results indicated that compounds 2-5 partly contributed to the anti-Oketsu effect of Shimotsu-To through the inhibition of platelet aggregation.

Chocolate intake increases urinary excretion of polyphenol-derived phenolic acids in healthy human subjects.

BACKGROUND: Proanthocyanidins, the most abundant polyphenols in chocolate, are not depolymerized in the stomach and reach the small intestine intact, where they are hardly absorbed because of their high molecular weight. In vitro and in vivo studies using pure compounds as substrates suggest that proanthocyanidins and the related catechin monomers may be degraded into more bioavailable low-molecular-weight phenolic acids by the microflora in the colon. OBJECTIVE: The aim of the study was to estimate the amounts of phenolic acids formed by the microflora and excreted in the urine of human subjects after consumption of polyphenol-rich chocolate. DESIGN: After consumption of a polyphenol-free diet for 2 d and a subsequent overnight fast, 11 healthy subjects (7 men and 4 women) consumed 80 g chocolate containing 439 mg proanthocyanidins and 147 mg catechin monomers. All urine was collected during the 24 h before chocolate consumption and at 3, 6, 9, 24, and 48 h after chocolate consumption. Aromatic acids were identified in urine by gas chromatography-mass spectrometry and were quantified by HPLC-electrospray ionization tandem mass spectrometry. RESULTS: Chocolate intake increased the urinary excretion of the 6 following phenolic acids: m-hydroxyphenylpropionic acid, ferulic acid, 3,4-dihydroxyphenylacetic acid, m-hydroxyphenylacetic acid, vanillic acid, and m-hydroxybenzoic acid. CONCLUSION: The antioxidant and biological effects of chocolate may be explained not solely by the established absorption of catechin monomers but also by the absorption of microbial phenolic acid metabolites.

Caffeic acid derivatives in artichoke extract are metabolised to phenolic acids in vivo.

The purpose of this study was to investigate the absorption and metabolism of hydroxycinnamates from artichoke extract by determining the urinary excretion of the conjugates. Ten healthy, non smoking volunteers (5 female, 5 male) were given three capsules containing artichoke extract every 4 h (0, 4, 8 h) following two days of a low-polyphenol diet. One capsule contained 320 mg of artichoke extract equivalent to 34.3 +/- 0.6 mg/g hydroxycinnamates (caffeic acid derivatives) and 5.6 +/- 0.1 mg/g flavonoids. Polyphenols and phenolic acids present in the artichoke extract were not detected in the urine either as conjugates or aglycones. However, ferulic, isoferulic, dihydroferulic and vanillic acid were identified as major metabolites after beta-glucuronidase treatment of urine. The amount excreted as well as the ratio to that of creatinine, a biomarker for the general excretion rate, increased significantly on the study day compared to the pre-supplementation day. Thus, the caffeic acid esters found in the artichoke extract capsule are absorbed, metabolised and excreted as methylated phenolic acids such as ferulic, isoferulic, dihydroferulic and vanillic acid.

Novel biomarkers of the metabolism of caffeic acid derivatives in vivo.

The purpose of this study was to investigate biomarkers of the bioavailability and metabolism of hydroxycinnamate derivatives through the determination of the pharmacokinetics of their urinary elimination and identification of the metabolites excreted. Coffee was used as a rich source of caffeic acid derivatives and human supplementation was undertaken. The results show a highly significant increase in the excretion of ferulic, isoferulic, dihydroferulic acid (3-(4-hydroxy-3-methoxyphenyl)-propionic acid), and vanillic acid postsupplementation relative to the levels presupplementation. Thus, ferulic, isoferulic, and dihydroferulic acids are specific biomarkers for the bioavailability and metabolism of dietary caffeic acid esters. Isoferulic acid is a unique biomarker as it is not a dietary component, however, dihydroferulic acid may well derive from other flavonoids with a structurally related B-ring. 3-Hydroxyhippuric acid has also been identified as an indicator for bioavailability and metabolism of phenolic compounds, and shows a highly significant excretion increase postsupplementation. The results reveal isoferulic acid (and possibly dihydroferulic acid) as novel markers of caffeoyl quinic acid metabolism.

High-performance liquid chromatographic method for determination of vanillin and vanillic acid in human plasma, red blood cells and urine.

A simple high-performance liquid chromatographic method was developed for the determination of vanillin and its vanillic acid metabolite in human plasma, red blood cells and urine. The mobile phase consisted of aqueous acetic acid (1%, v/v)-acetonitrile (85:15, v/v), pH 2.9 and was used with an octadecylsilane analytical column and ultraviolet absorbance detection. The plasma method demonstrated linearity from 2 to 100 microg/ml and the urine method was linear from 2 to 40 microg/ml. The method had a detection limit of 1 microg/ml for vanillin and vanillic acid using 5 microl of prepared plasma, red blood cells or urine. The method was utilized in a study evaluating the pharmacokinetic and pharmacodynamic effects of vanillin in patients undergoing treatment for sickle cell anemia.

[Follow up control of stage IV neuroblastoma: 123I-MIBG scintigraphy, bone scintigraphy and catecholamine metabolites]. / Verlaufskontrolle des Neuroblastoms Stadium IV: 123I-mIBG-Szintigraphie, Knochenszintigraphie und Katecholaminmetabolite.

AIM: The diagnostic value of 123I-mIBG-scintigraphy, bone scintigraphy and catecholamine metabolites in the follow up of neuroblastoma stage IV will be evaluated. METHODS: Nineteen children suffering from neuroblastoma were analysed retrospectively by 123I-mIBG-scintigraphy, bone scintigraphy and measurement of homovanillic acid, vanillic acid, neuronspecific enclose, lactate dehydrogenase, and ferritine. Follow up was 7-132 (median 36) months. RESULTS AND CONCLUSION: The significance of the methods was dependent on the time of diagnostic use. In principal, 123I-mIBG-scintigraphy has the highest diagnostic impact. For initial staging and diagnosis of recurrence a combination of all three methods can be used. On the contrary, follow up during chemotherapy is best documented by 123I-mIBG-scintigraphy, whereas bone scintigraphy is of limited and measurement of catecholamine metabolites of less diagnostic value.

High-performance liquid chromatographic determination of catecholamine metabolites and 5-hydroxyindoleacetic acid in human urine using a mixed-mode column and an eight-channel electrode electrochemical detector.

An HPLC system for the simultaneous determination of acidic catecholamine metabolites, related compounds and 5-hydroxyindoleacetic acid (5-HIAA) in human urine was developed. A mixed-mode (C18/anion-exchange) column with isocratic elution using citrate buffer and an eight-channel electrochemical detector were used. Vanilmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid (DOPAC), 4-hydroxy-3-methoxyphenyllactic acid (vanillactic acid, VLA), homovanillic acid (HVA), vanillic acid (VA) and 5-HIAA in urine were determined simultaneously. Detection limits and inter (n = 5) and intra-assay (n = 5) coefficients of variation were satisfactory. The mean of analytical recoveries (n = 3, +/- C.V. (%)) were between 97 +/- 3.2 (VMA) and 105 +/- 4.8 (VA). Correlations between the analytical results for VMA, HVA and 5-HIAA obtained by an established method and the present method were satisfactory. The mean +/- 2 S.D. of the excretion rates of VMA, DOPAC, VLA, HVA, 5-HIAA and VA in urine from healthy adult volunteers were 0.61-4.36, 0.13-1.02, 0-0.35, 0.67-6.55, 0.50-5.14 and 0-0.55 mg/g creatinine, respectively.

Effect of the intestinal flora on the urinary organic acid profile of rats ingesting a chemically simplified diet.

In order to estimate the influence of gut bacteria on animal metabolism, the excretion of organic acids, as monitored by gas-liquid chromatography, was compared in the urines of conventional and germ-free rats. Rats were maintained on a chemically simplified diet in order to minimize the effect of strictly exogenous compounds on the organic acid profile. Initial analysis of the excretion rates of 68 compounds, found reproducibly in the profile, indicated significant day-to-day and rat-to-rat variation, suggesting that haphazard comparison of experimental groups of animals might yield spurious differences with no biological significance. When repeated measures of the profile were analysed by a random effects analysis of variance model, no compound was found exclusively in the urine of either conventional or germ-free rats. Nevertheless, tricarballylate was significantly higher and both tartronate and vanillate significantly lower in conventional rat urine. The flora was implicated in these differences because caecal contents of conventional rats were found to convert such tricarboxylic acids as cis- and trans-aconitate to tricarballylate and to cause the dissimilation of both vanillate and tartronate, the latter compound being of dietary origin.

Effects of the mass screenings for neuroblastoma in Japan. A study of 68 cases.

Sixty-eight cases of neuroblastoma detected during mass screening being performed by 11 local self-governing bodies of Japan were studied concerning age, clinical stage, and survival rate. Their average ages at the first screening, at the beginning of thorough examination, and at the start of therapy were 215.7, 245.6, and 264.7 days, respectively. This screening, which is aimed at the 6-month-old infants is considered to be acceptable, on the grounds that the majority of the cases (95.6%) were asymptomatic at the time of thorough examination, that for most of the cases (98.5%) the initiation of therapy was at under 1 year of age, and that their 60-month survival rate was 87.5%. However, there seems to be room for discussion of the best age at which subjects should be screened, because the 68 cases included some patients already with advanced stages at the time of thorough examination, and because "false negative cases" were identified besides the 68 positive cases.

Small-volume electrochemical detector for microcolumn liquid chromatography.

A submicroliter electrochemical detector for liquid chromatography has been designed, using pressure-annealed pyrolytic graphite technology. The analytical performance of this detector was studied in connection with a reversed-phase packed microcapillary column at very low flow-rates. Although the miniaturized version of the electrochemical detector is less sensitive, a direct analysis of a number of urinary metabolites in 0.1--1.0 microliters samples is feasible.

Urinary excretion of conjugated homovanillic acid, 3,4-dihydroxyphenylacetic acid, p-hydroxyphenylacetic acid, and vanillic acid by persons on their usual diet and patients with neuroblastoma.

We report quantitative data on beta-glucuronidase- and sulfatase-hydrolyzable conjugates of homovanillic acid, 3,4-dihydroxyphenylacetic acid, p-hydroxyphenylacetic acid, and vanillic acid in the urine of 20 apparently normal and healthy control persons and of three patients with neuroblastoma. We used organic solvent extraction and capillary gas chromatography. There was considerable person-to-person variation in the conjugation percentages calculated. Mean conjugated percentages of the four compounds for 16 normal healthy persons 2.5--40 years of age were, respectively, 12%, 33%, 14%, and 35%. For newborns and patients with neuroblastoma, these percentages were somewhat different. Increased amounts of vanillic acid were found in the urine of the patients with neuroblastoma, but results of a small metabolic study in rats suggest that this increase most probably is of dietary origin.

Gas chromatographic determination of urinary vanilglycolic acid, vanilglycol, vanilacetic acid and vanillactic acid-chemical parameters for the diagnosis of neurogenic tumours and the evaluation of their treatment.

A gas chromatographic method is described for the determination of urinary vanilglycolic acid, vanilglycol, vanilacetic acid and vanillactic acid as their trimethylsilyl derivatives. These metabolites are chemical parameters for the dignosis of neurogenic tumours. Their determination is especially recommended in order to evaluate the effect of the therapy. Results in normals and controls are given. Data in a number of selected patients with neuroblastoma, ganglioneuroma and phaeochromocytoma are presented and discussed.

Thin-layer chromatography for diagnosis of secreting neuroblastoma.

A thin-layer chromatographic technique for separation and identification of urinary phenolic acids is described. The method is simple enough to be used in the clinical laboratory and from it, an easy biochemical diagnosis of secreting neuroblastoma. The technique is also of interest for research in catabolism of catecholamines. Results obtained in 125 patients, including 8 patients with neuroblastoma are reported.

Para-O-methylation of the catecholamines in neuroblastoma.

By means of thin-layer chromatographic methods, iso-homovanillic acid (iso-HVA), iso-vanillactic acid (iso-VLA) and iso-vanilmandelic acid (iso-VMA) were determined in the urine of 10 children with neuroblastoma. The mean excretion of iso-HVA was 10.1% of total HVA excretion. Three patients excreted VLA; in their urine no iso-VLA was detected with certainty. All patients excreted high amounts of VMA; there was no detectable excretion of iso-VMA. Those results suggest that para-O-methylation could be limited to dopamine catabolism.