Processing 'Ataulfo' Mango into Juice Preserves the Bioavailability and Antioxidant Capacity of Its Phenolic Compounds.

The health-promoting effects of phenolic compounds depend on their bioaccessibility from the food matrix and their consequent bioavailability. We carried out a randomized crossover pilot clinical trial to evaluate the matrix effect (raw flesh and juice) of 'Ataulfo' mango on the bioavailability of its phenolic compounds. Twelve healthy male subjects consumed a dose of mango flesh or juice. Blood was collected for six hours after consumption, and urine for 24 h. Plasma and urine phenolics were analyzed by electrochemical detection coupled to high performance liquid chromatography (HPLC-ECD). Five compounds were identified and quantified in plasma. Six phenolic compounds, plus a microbial metabolite (pyrogallol) were quantified in urine, suggesting colonic metabolism. The maximum plasma concentration (Cmax) occurred 2-4 h after consumption; excretion rates were maximum at 8-24 h. Mango flesh contributed to greater protocatechuic acid absorption (49%), mango juice contributed to higher chlorogenic acid absorption (62%). Our data suggests that the bioavailability and antioxidant capacity of mango phenolics is preserved, and may be increased when the flesh is processed into juice.

[The characteristics of interpretation of results of analysis of protein amount in urine of pregnant women].

The adequacy of implementation of present proteinuria diagnostic thresholds under examination of pregnant women was examined. The analysis was applied to all urine samples of pregnant women from December 2009 to March 20010. The amount of protein in urine was concurrently evaluated by turbidimetric analysis with sulfosalicylic acid, colorimetric analysis with pyrogallol red, "dry chemistry" technology (the diagnostic strips). It is established that the mentioned techniques of analysis of protein in urine provide independent results. The results of colorimetric analysis are characterized by better precision and adequacy. However, in case of pregnant women the diagnostic threshold of protein concentration should be shifted from 0.120 to 0.150 g/l.

Impact of short-term intake of red wine and grape polyphenol extract on the human metabolome.

Red wine and grape polyphenols are considered to promote cardiovascular health and are involved in multiple biological functions. Their overall impact on the human metabolome is not known. Therefore, exogenous and endogenous metabolic effects were determined in fasting plasma and 24 h urine from healthy male adults consuming a mix of red wine and grape juice extracts (WGM) for 4 days in a placebo-controlled, crossover study. Syringic acid, 3-hydroxyhippuric acid, pyrogallol, 3-hydroxyphenylacetic acid, and 3-hydroxyphenylpropionic acid were confirmed as the strongest urinary markers of WGM intake. Overall, WGM had a mild impact on the endogenous metabolism. Most noticeable were changes in several amino acids deriving from tyrosine and tryptophan. Reductions in the microbial metabolites p-cresol sulfate and 3-indoxylsulfuric acid and increases in indole-3-lactic acid and nicotinic acid were observed in urine. In plasma, tyrosine was reduced. The results suggest that short-term intake of WGM altered microbial protein fermentation and/or amino acid metabolism.

Occupational exposure to phenolic compounds at coke plants--urinary excretion of methoxyphenols as an indicator of exposure to methoxyphenols.

OBJECTIVES: This study describes the exposure of coke plant workers to methoxyphenols. The relationship between exposure to methoxyphenols and urinary excretion of metabolites was examined. METHODS: We determined concentrations of 2-methoxyphenol, 2-methoxy-4-methylphenol and 1-(4-hydroxy-3-methoxyphenyl)ethanone in the breathing-zone air and in the urine of workers, collected after the workshift. Urine metabolites were extracted after enzymatic hydrolysis by solid-phase extraction. Concentrations of methoxyphenols in air and urine were determined by gas chromatography with flame-ionization. RESULTS: The time-weighted average concentrations (median) of methoxyphenols in the breathing zone air were as follows: 9.9 ng/m(3), 15.4 ng/m(3) and 92.5 ng/m(3) for 2-methoxyphenol, 2-methoxy-4-methylphenol and 1-(4-hydroxy-3-methoxyphenyl)ethanone, respectively. The median values of urinary concentrations were as follows: 582.5, 190.1, 235.0 and 21.8 µmol/mol creatinine for 2-methoxyphenol, 2-methoxy-4 methylphenol, 1-(4-hydroxy-3-methoxyphenyl)ethanone and 2,6-dimethoxyphenol, respectively. A statistically significant correlation between the exposure level and the urinary level was found for 2-methoxyphenol (r=0.573, p<0.01). CONCLUSION: We found that the presence of 2-methoxyphenol in urine can be used as a biomarker for 2-methoxyphenol exposure. The analysis performed at the coke plant showed that the workers were exposed to relatively low concentrations of methoxyphenols.

Antioxidant capacity of human blood plasma and human urine: simultaneous evaluation of the ORAC index and ascorbic acid concentration employing pyrogallol red as probe.

The oxygen radical absorbance capacity (ORAC) methodology has been employed to estimate the antioxidant capacity of human blood plasma and human urine using pyrogallol red (ORAC-PGR) as target molecule. Uric acid, reduced glutathione, human serum albumin, and ascorbic acid (ASC) inhibited the consumption of pyrogallol red, but only ASC generated an induction time. Human blood plasma and human urine protected efficiently pyrogallol red. In these assays, both biological fluids generated neat induction times that were removed by ascorbate oxidase. From these results, ORAC-PGR method could be proposed as a simple alternative to evaluate an ORAC index and, simultaneously, to estimate the concentration of ascorbic acid in human blood plasma or human urine.

Determination of phenolic compounds derived from hydrolysable tannins in biological matrices by RP-HPLC.

An RP-HPLC method for the determination of four phenolic compounds: gallic acid (GA), pyrogallol (PY), resorcinol (RE) and ellagic acid (EA), derived from hydrolysable tannins is reported. Separation was achieved on a SunFire C18 (250 x 4.6 mm id, 5 microm) column at 40 degrees C with gradient elution. UV detection at 280 nm was applied. The developed method was validated in terms of linearity, accuracy and precision. Satisfactory repeatability and between day precision were noticed with RSD values lower than 3%. Recoveries from different biological samples ranged from 91.50 to 105.25%. The LODs were estimated as 1.70 mg/L for PY, 1.68 mg/L for GA, 1.52 mg/L for RE and 0.98 mg/L for EA with a 20 microL injection volume. The method was applied for the determination of these compounds in oak leaves and in ruminal fluid and urine samples taken from beef cattle fed with oak leaves. The proposed method could be used in ruminant nutrition studies to verify the effect that a diet rich in tannins have on ruminal fermentation and to determine the toxicity of these compounds.

Development of a stable isotope dilution analysis with liquid chromatography-tandem mass spectrometry detection for the quantitative analysis of di- and trihydroxybenzenes in foods and model systems.

A straightforward stable isotope dilution analysis (SIDA) for the quantitative determination of the di- and trihydroxybenzenes catechol (1), pyrogallol (2), 3-methylcatechol (3), 4-methylcatechol (4), and 4-ethylcatechol (5) in foods by means of liquid chromatography-tandem mass spectrometry was developed. With or without sample preparation involving phenylboronyl solid phase extraction, the method allowed the quantification of the target compounds in complex matrices such as coffee beverages with quantification limits of 9 nmol/L for 4-ethylcatechol, 24 nmol/L for catechol, 3-methyl-, and 4-methylcatechol, and 31 nmol/L for pyrogallol. Recovery rates for the analytes ranged from 97 to 103%. Application of the developed SIDA to various commercial food samples showed that quantitative analysis of the target compounds is possible within 30 min and gave first quantitative data on the amounts of di- and trihydroxybenzenes in coffee beverage, coffee powder, coffee surrogate, beer, malt, roasted cocoa powder, bread crust, potato crisps, fruits, and cigarette smoke and human urine. Model precursor studies revealed the carbohydrate/amino acid systems as well as the plant polyphenols catechin and epicatechin as precursors of catechol and 5-O-caffeoylquinic acid, caffeic acid as a precursor of catechol and 4-ethylcatechol, and gallocatechin, epigallocatechin, and gallic acid as precursors of pyrogallol.

Abuse of nutmeg (Myristica fragrans Houtt.): studies on the metabolism and the toxicologic detection of its ingredients elemicin, myristicin, and safrole in rat and human urine using gas chromatography/mass spectrometry.

Seeds of nutmeg are used as spice, but they are also abused because of psychotropic effects described after ingestion of large doses. It was postulated that these effects could be attributable to metabolic formation of amphetamine derivatives from the main nutmeg ingredients elemicin (EL), myristicin (MY), and safrole (SA). In a case of a suspected nutmeg abuse, neither such amphetamine derivatives nor the main nutmeg ingredients could be detected in urine. The metabolites of EL, MY, and SA were identified using gas chromatography-mass spectrometry in rat urine and their presence in human urine of the nutmeg abuser was confirmed. The identified metabolites indicated that EL, MY, and SA were once and twice hydroxylated at the side chain. In addition, EL was O-demethylated at 2 positions followed by side chain hydroxylation. MY and SA were demethylenated and subsequently methylated. In the human urine sample, the following metabolites could be identified: O-demethyl elemicin, O-demethyl dihydroxy elemicin, demethylenyl myristicin, dihydroxy myristicin, and demethylenyl safrole. As in the human urine sample, neither amphetamine derivatives nor the main nutmeg ingredients could be detected in the rat urine samples. Finally, toxicologic detection of nutmeg abuse was possible by identification of the described metabolites of the EL, MY, and SA in urine applying the authors' systematic toxicologic analysis procedure using full-scan gas chromatography-mass spectrometry after acid hydrolysis, liquid-liquid extraction of analytes, and microwave-assisted acetylation of extracted analytes.

Simultaneous determination of 2-methoxyphenol, 2-methoxy-4-methylphenol, 2,6-dimethoxyphenol and 4'-hydroxy-3'-methoxyacetophenone in urine by capillary gas chromatography.

A method for the simultaneous determination of 2-methoxyphenol, 2-methoxy-4-methylphenol, 2,6-dimethoxyphenol and 4'-hydroxy-3'-methoxyacetophenone in urine has been described. The metabolites were analyzed after enzymatic hydrolysis and extraction on octyl (C8) cartridges by using gas chromatography with flame ionization detection and a 5/95% copolymer of diphenyl-poly(dimethylsiloxane) capillary column. Methoxyphenols were well separated within 12 min. Recovery was over 90% in the range from 0.5 to 20 microg/ml; the detection limit was varying in the range of 0.05-0.11 microg/ml. The relative standard deviations and the accuracy were in the range of 3.1-15.5 and 2.4-16.0%, respectively.

Method for analysis of tannic acid and its metabolites in biological samples: application to tannic acid metabolism in the rat.

A new analytical method for measuring tannic acid (TA) using tannase was developed and applied to the investigation of TA metabolism in the rat following oral administration at a dose of 1.0 g/kg. The proposed method for TA determination was based on the enzymatic hydrolysis of TA to gallic acid (GA) and subsequent determination by HPLC. TA metabolites were determined by HPLC. 4-O-Methylgallic acid (4-OMGA), pyrogallol (PY), and resorcinol (RE) were detected in serum. TA was excreted into urine as GA (0.01%), 4-OMGA (0.10%), PY (0.24%), and RE (2.06%) and into feces as TA (62.74%), GA (0.19%), PY (0.02%), and RE (0.76%) within 54 h after oral administration. It was suggested that >60% of TA remained unchanged but that some was hydrolyzed to GA by tannase in the intestine and further metabolized to 4-OMGA, PY, and RE.

Determination of gallic acid and its metabolites in human plasma and urine by high-performance liquid chromatography.

Gallic acid occurs naturally in plants and has been found to be pharmacologically active as antioxidant, antimutagenic and anticarcinogenic agent. In this work, the metabolism of gallic acid in the human body was investigated. Two methods were developed for the identification and determination of gallic acid and its phenolic metabolites in human plasma and urine by reversed-phase high-performance liquid chromatography using UV detection and involving isocratic elution. One of these methods enables the simultaneous separation and determination of gallic acid (GA), 4-O-methylgallic acid (4OMGA), pyrogallol (PY), 2-O-methylpyrogallol (2OMPY) and resorcinol (RE) in biological fluids. This method is of interest because it allows the separation of a large number of phenolic compounds by isocratic elution using a solution of 4.4 x 10(-3) M phosphoric acid in water as mobile phase. The analysis time for this method, however, is not optimal (57 min). After oral administration of 50 mg GA, 4OMGA rapidly appeared in the plasma and urine besides unchanged GA. Other phenolic compounds, PY, 2OMPY and RE, were not detected. The second method was developed to determine GA and 4OMGA with a short analysis time (25 min).