Chemical species of organotin compounds in sediment at a marina.

A bottom sediment collected in a marina was analyzed for organotin species, and >20 organotin compounds including biodegraded ones were confirmed by comparison with the synthesized standards using gas chromatography (GC)/mass spectrometry and a GC/atomic emission detection system. Their structures were also determined in comparison with those in a technical grade of tri-n-butyltin chloride (TBTC). Eleven organotin compounds were found in the technical TBTC. Among them, unexpected organotin compounds, such as di-n-butyl(2-ethylhexyl)tin chloride and di-n-butyloctyltin chloride, were identified, although the levels were low. These compounds were also found in the sediment sample. The relationship between organotin compounds in the technical TBTC and those in marine products was also discussed.     

Volatile organic sulfur-containing constituents in Poncirus trifoliata (L.) Raf. (Rutaceae)

During our screening of plant materials to find new natural fragrance and flavor ingredients, we discovered two series of 3-sulfanylalkyl alkanoates in a peel extract of fruits of wild-growing Poncirus trifoliata (L.) Raf. (Rutaceae), a species closely related to Citrus. The two series belong to alkanoates of 3-methyl-3-sulfanylbutan-1-ol and 3-sulfanylhexan-1-ol, respectively, and thus are members of a family of natural molecules having in common a 1,3-positioned O,S moiety. The alkanoate residues comprise all even-numbered saturated fatty acids from C2 (acetate) to C18 (octadecanoate). Among the 20 sulfur-containing compounds identified, 14 are described for the first time as naturally occurring in a botanical species. Several cysteine-S-conjugates were synthesized as hypothetical precursors of the new volatile sulfur-containing constituents, where after S-(3-hydroxy-1,1-dimethylpropyl)-L-cysteine, S-[3-(acetyloxy)-1,1-dimethylpropyl]-L-cysteine, and S-[1-(2-hydroxyethyl)butyl]-L-cysteine were identified in the fruit peel. No cysteine-S-conjugates were detected in the fruit juice.     

Rapid and sensitive HILIC-ESI-MS/MS quantitation of polar metabolites of acrylamide in human urine using column switching with an online trap column

The carcinogen acrylamide (AA) is formed during the processing of food. AA is metabolized to mercapturic acids, which are excreted with urine. A hydrophilic interaction liquid chromatography tandem mass spectrometry method (HILIC-MS/MS) using a zwitterionic stationary phase (Zic-HILIC) was developed and validated to quantitate the mercapturic acids of AA (AAMA) and glycidamide (GAMA), and AAMA-sulfoxide in human urine. In contrast to reversed phases, the application of Zic-HILIC resulted in efficient retention and separation of these highly polar compounds. Off-line sample workup was avoided by application of column switching with a Stability BS-C17 trap column prior to the analytical column, thus minimizing interferences with the urinary matrix. Limit of quantification values (LOQs) were 0.5 microg/L (AAMA), 2.0 microg/L (AAMA-sulfoxide), and 1.0 microg/L (GAMA) in human urine. Median concentrations in urine samples ( n = 54) of six nonsmoking human subjects were 24.0 microg/L (AAMA, 7.8-79.8 microg/L), 16.7 microg/L (AAMA-sulfoxide, 6.8-70.1 microg/L), and 3.82 microg/L (GAMA, 1.0-23.6 microg/L).     

Development of a class-selective enzyme-linked immunosorbent assay for mercapturic acids in human urine

Epidemiological and toxicological studies often require the analysis of large numbers of samples for biological markers of exposure. The goal of this work was to develop a class-selective ELISA to detect groups of structurally closely related mercapturic acids with small nonpolar S-substituents. An assay was developed with strong recognition for mercapturates including S-benzylmercapturic acid (IC50 = 0.018 micromol/L), S-n-hexylmercapturic acid (IC50 = 0.021 micromol/L), S-phenylmercapturic acid (IC50 = 0.024 micromol/L), and S-cyclohexylmethylmercapturic acid (IC50 = 0.042 micromol/L). The same assay also showed weaker recognition for S-(1-hydroxynaphthal-2-yl)mercapturic acid and S-allylmercapturic acid (IC50 = 1.1 and 1.7 micromol/L, respectively). Subtle modifications to the hapten linker structure of the coating antigen proved to have a strong impact on the selectivity and the specificity of the assay. A slightly modified assay showed high recognition for S-benzylmercapturic acid (IC50 = 0.018 micromol/L) and weaker recognition for seven other mercapturic acids (IC50 = 0.021-10 micromol/L). Strong positive assay responses were detected in 12 urine samples obtained from persons with no known occupational exposure to exogenous electrophilic xenobiotics. Solid phase extraction and cross-reactivity indicated that the presumptive immunoreactive materials were similar in size and polarity to S-benzylmercapturic acid. The assay was more selective to mercapturic acids than the spectrophotometric thioether assay.     

Metabolism of diethofencarb (isopropyl 3,4-diethoxyphenylcarbamate) in rats: identification of metabolites in urine

Rats were orally given a diethofencarb (isopropyl 3,4-diethoxyphenylcarbamate) labeled with (14)C, at 300 mg/kg/day, for 4 consecutive days, and 11 metabolites in urine were purified by a combination of several chromatographic techniques. The chemical structures of all isolated metabolites were identified by spectroanalyses (NMR and MS). Ten of them were newly identified forms. Five of them were S-conjugates: three mercapturic acid conjugates, one S-methyl conjugate, and one SO-methyl conjugate. The others were two phenoxyacetic acids, hydroxyacetanilide, hydroxyisopropyl carbamate, and oxazolinone derivatives. From the results, the existence of the following reactions in rats can be concluded: (1) deethylation of the 4-ethoxy group; (2) conjugation of phenols with glutathione, gamma-glutamyltranspeptidation and depeptidation of the glutathione to form cysteine conjugates, and N-acetylation of the cysteine; (3) cleavage of the C-S linkage of cysteine conjugates followed by methylation; (4) oxidation of the S-methyl group; (5) cleavage of the carbamate linkage; (6) acetylation of the resultant amino group; (7) oxidation of the acetyl group; (8) oxidation of the isopropyl group; (9) cyclization of the oxidized isopropyl carbamate group; and (10) oxidation of the 4-ethoxy group.     

Hemoglobin adducts and mercapturic acid excretion of acrylamide and glycidamide in one study population

The aim of this study was to determine the relationship between the oxidative and reductive metabolic pathways of acrylamide (AA) in the nonsmoking general population. For the first time both the blood protein adducts and the urinary metabolites of AA and glycidamide (GA) were quantified in an especially designed study group with even distribution of age and gender. The hemoglobin adducts N-carbamoylethylvaline (AAVal) and N-( R, S)-2-hydroxy-2-carbamoylethylvaline (GAVal) were detected by GC-MS/MS in all blood samples with median levels of 30 and 34 pmol/g of globin, respectively. Concentrations ranged from 15 to 71 pmol/g of globin for AAVal and from 14 to 66 pmol/g of globin for GAVal. The ratio GAVal/AAVal was 0.4-2.7 (median = 1.1). The urinary metabolites were determined by LC-MS/MS. Of all urine samples examined 99% of N-acetyl- S-(2-carbamoylethyl)- l-cysteine (AAMA) levels and 73% of N-( R/ S)-acetyl- S-(2-carbamoyl-2-hydroxyethyl)- l-cysteine (GAMA) levels were above the LOD (1.5 microg/L). Concentrations ranged from 相似文献   

Nonvolatile S-alk(en)ylthio-L-cysteine derivatives in fresh onion (Allium cepa L. cultivar)

The L-cysteine derivatives (R)-2-amino-3-(methyldisulfanyl)propanoic acid (S-methylthio-L-cysteine), (R)-2-amino-3-(propyldisulfanyl)propanoic acid (S-propylthio-L-cysteine), (R)-2-amino-3-(1-propenyldisulfanyl)propanoic acid (S-(1-propenylthio)-L-cysteine), and (R)-2-amino-3-(2-propenyldisulfanyl)propanoic acid (S-allylthio-L-cysteine) were prepared from 3-[(methoxycarbonyl)dithio]-L-alanine, obtained from the reaction of L-cysteine with methoxycarbonylsulfenyl chloride. The occurrence of these S-(+)-alk(en)ylthio-L-cysteine derivatives in onion (Allium cepa L.) was proven by using UPLC-MS-ESI(+) in SRM mode. Their concentrations in fresh onion were estimated to be 0.19 mg/kg S-methylthio-L-cysteine, 0.01 mg/kg S-propylthio-L-cysteine, and 0.56 mg/kg (S-(1-propenyllthio)-L-cysteine, concentrations that are about 3000 times lower than that of isoalliin (S-(1-propenyl-S-oxo-L-cysteine). These compounds were treated with Fusobacterium nucleatum, a microorganism responsible for the formation of mouth malodor. These L-cysteine disulfides were demonstrated to predominantly produce tri- and tetrasulfides. Isoalliin is almost entirely consumed by the plant enzyme alliin lyase (EC 4.4.1.4 S-alk(en)yl-S-oxo-L-cysteine lyase) in a few seconds, but it is not transformed by F. nucleatum. This example of flavor modulation shows that the plant produces different precursors, leading to the formation of the same types of volatile sulfur compounds. Whereas the plant enzyme efficiently transforms S-alk(en)yl-S-oxo-L-cysteine, mouth bacteria are responsible for the transformation of S-alk(en)ylthio-L-cysteine.     

Metabolism of [(1)(4)C]prometryn in rats.

[(1)(4)C]Prometryn, 2, 4-bis(isopropylamino)-6-(methylthio)-s-triazine, was orally administered to male and female rats at approximately 0.5 and 500 mg/kg; daily urine and feces were collected. After 3 or 7 days rats were sacrificed, and blood and selected tissues were isolated. The urine and feces extracts were characterized for metabolite similarity as well as for metabolite identification. Over 30 metabolites were observed, and of these, 28 were identified mostly by mass spectrometry and/or cochromatography with available reference standards. The metabolism of prometryn was shown to occur by N-demethylation, S-oxidation, S-S dimerization, OH substitution for NH(2) and SCH(3), and conjugation with glutathione or glucuronic acid. Rat liver microsomal incubations of prometryn were conducted and compared to the in vivo metabolism. Both in vivo and in vitro phase I metabolisms of prometryn were similar, with S-oxidation and N-dealkylation predominating. The involvement of cytochrome P-450 and flavin-containing monooxidase in the in vitro metabolism of prometryn was investigated.     

Mössbauer studies of the speciation of tributyltin compounds in seawater and sediment samples

The antifoulant agents, bis-(tributyltin) oxide (TBTO), tributyltin acetate (TBTOAc) and tributyltin chloride (TBTCI) were mixed with various media. These media included distilled water, seawater, aerobic and anaerobic sediments. The Mossbauer spectra of the chloroform extracts of the distilled water and seawater mixed with these compounds were examined. The componds were mixed with aerobic and anaerobic sediments, and the Mossbauer spectra of the sediments were also examined. TBTO was converted to the hydroxide compound in all media except in anaerobic sediment where it was converted to an unidentified compound. TBTOAc and TBTCI were not changed by mixing with distilled water and aerobic sediment but were converted to the hydroxide compound in seawater and in anaerobic sediment.     

Elevated carbon dioxide increases contents of antioxidant compounds in field-grown strawberries

The effects of elevated CO2 concentrations on the antioxidant capacity and flavonoid content in strawberry fruit (Fragaria x ananassa Duch.) were studied under field conditions. Increased CO(2) (300 and 600 micromol mol(-1) above ambient) concentrations resulted in increases in ascorbic acid (AsA), glutathione (GSH), and ratios of AsA to dehydroascorbic acid (DHAsA) and GSH to oxidized glutathione (GSSG), and a decrease in DHAsA in strawberry fruit. High anthocyanin and phenolic content were also found in fruit of CO(2) treated plants. Growing strawberry plants under CO(2) enrichment conditions significantly enhanced fruit p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, and kaempferol 3-glucoside contents, as well as cyanidin 3-glucoside, pelargonidin 3-glucoside, and pelargonidin 3-glucoside-succinate content. Fruit of strawberry plants grown in the CO(2) enrichment conditions also had high oxygen radical absorbance activity against ROO(*), O(2)(*-), H(2)O(2), OH(*), and (1)O(2) radicals.     

New cysteine-S-conjugate precursors of volatile sulfur compounds in bell peppers (Capsicum annuum L. cultivar)

The objective of this study was to verify whether the volatile organic sulfur compounds recently discovered in bell pepper (Capsicum annuum, L. cultivars), such as the mercapto-ketones: 4-sulfanyl-2-heptanone and 2-sulfanyl-4-heptanone, the mercapto-alcohols: 4-sulfanyl-2-heptanol and 2-sulfanyl-4-heptanol, and heptane-2,4-dithiol, originate from their corresponding cysteine-S-conjugates. Analysis of aqueous extracts of red and green bell pepper by ultraperformance liquid chromatography-mass spectrometry with electrospray ionization in the positive mode (UPLC-MS ESI(+)) displayed masses corresponding to the expected cysteine-S-conjugates. To confirm this observation, four cysteine-S-conjugates were prepared as authentic samples: S-(3-hydroxy-1-methylhexyl)-L-cysteine, S-(3-hydroxy-1-propylbutyl)-L-cysteine, S-(3-oxo-1-propylbutyl)-L-cysteine, and (2R,2'R)-3,3'-(4-hydroxyheptane-2,6-diyl)bis(sulfanediyl) bis(2-aminopropanoic acid). By comparison with the fragmentation patterns and retention times of synthetic mixtures of cysteine-S-conjugate diastereoisomers, the natural occurrence of cysteine conjugates was confirmed in bell peppers. In addition, the cysteine-S-conjugates from red and green bell pepper extracts were concentrated by ion exchange chromatography and the fractions incubated with a β-lyase (apotryptophanase). The liberated thiols were concentrated by affinity chromatography, and their occurrence, detected by gas chromatography-mass spectrometry, confirmed our predictions. Moreover, 3-sulfanyl-1-hexanol was also detected and the occurrence of S-(1(2-hydroxyethyl)butyl)-L-cysteine confirmed. A quantitative estimation based on external calibration curves, established by UPLC-MS ESI(+) in selected reaction monitoring mode, showed that cysteine-S-conjugates were present at concentrations in the range of 1 to 100 μg/kg (±20%).     

气调处理对绿芦笋抗氧化及抗病酶活性的影响

为探讨气调处理对绿芦笋抗氧化和抗病性相关酶活性的影响,以空气为对照(CK),在15±1℃和相对湿度为90%~95%的贮藏条件下,研究5种不同比例气体成分[CA1(5%CO_2+1.5%O_2)、CA2(7%CO_2+0%O_2)、CA3(7%CO_2+1.5%O_2)、CA4(7%CO_2+3.5%O_2)、CA5(9%CO_2+1.5%O_2)]对达宝利绿芦笋采后感官品质、菌落总数、相对电导率、丙二醛(MDA)含量、总酚含量、二苯基苦基苯肼(DPPH)清除率、羟自由基(·OH)清除率以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)活性的影响。结果表明,气调处理不同程度抑制了芦笋根部的腐烂,延缓了其菌落总数、相对电导率和MDA含量的上升,维持其较高的总酚含量、DPPH清除率、·OH清除率以及SOD、CAT、PPO活性,减缓了其POD活性上升,并保持了组织较低的PAL活性,所有气调处理中以CA3效果较好。此外,以绿芦笋根部开始出现腐烂为标准,CK、CA1、CA2、CA4、CA5和CA3的贮藏期分别为1、2、2、2、4和5 d。因此,CA3(7%CO_2+1.5%O_2)的气调处理可维持达宝利绿芦笋采后较好品质。本研究结果为绿芦笋的贮藏保鲜提供了理论依据及技术支持。     

LC-MS/MS quantification of sulforaphane and indole-3-carbinol metabolites in human plasma and urine after dietary intake of selenium-fortified broccoli

This study aimed at developing a sensitive LC-MS/MS method for the quantification of sulforaphane (SFN) and indole-3-carbinol metabolites in plasma and urine after dietary intake of regular and selenium-fertilized broccoli using stable isotope dilution analysis. In a three-armed, placebo-controlled, randomized human intervention study with 76 healthy volunteers, 200 g of regular (485 μg of total glucosinolates and <0.01 μg of selenium per gram fresh weight) or selenium-fertilized broccoli (589 μg of total glucosinolates and 0.25 μg of selenium per gram fresh weight) was administered daily for 4 weeks. Glucoraphanin and glucobrassicin metabolites quantified in plasma and urine were SFN-glutathione, SFN-cysteine, SFN-cysteinylglycine, SFN-acetylcysteine, and indole-3-carboxaldehyde, indole-3-carboxylic acid, and ascorbigen, respectively. Dietary intake of selenium-fertilized broccoli increased serum selenium concentration analyzed by means of atomic absorption spectroscopy by up to 25% (p < 0.001), but affected neither glucosinolate concentrations in broccoli nor their metabolite concentrations in plasma and urine compared to regular broccoli.     

Enzyme-linked immunosorbent assay for T-2 toxin metabolites in urine

A direct competitive enzyme-linked immunosorbent assay (ELISA) for determination of total T-2 toxin metabolites in urine was developed. The assay involves coating anti-3-acetyl-neosolaniol-hemisuccinate-bovine serum albumin conjugate (anti-3-Ac-NEOS-HS-BSA) antibody to the ELISA plate and using 3-Ac-NEOS-HS-peroxidase as the enzyme marker. Competitive ELISA revealed that the antibody had good cross-reactivity with acetyldiacetoxyscirpenol (Ac-DAS), T-2 tetraol tetraacetate, 3'-OH-Ac-T-2, 3-Ac-NEOS, and 3,4,15-triacetyl-12,13-epoxytrichothec-9-en-8-one (Ac-T-2-8-one), but less cross-reactivity with Ac-T-2 toxin and T-2 toxin. All metabolites of T-2 toxin in urine were converted to T-2 tetraol tetraacetate (T-2-4ol-4Ac) by acetylation of the sample extract before ELISA. To test the ELISA accuracy, a radioimmunoassay (RIA) was performed simultaneously. The linear portion of the standard curve of this direct ELISA for T-2-4ol-4Ac was 0.2-2.0 ng/mL, which was 10 times more sensitive than RIA. The minimum detection level for T-2-4ol-4Ac was 0.02 ng/mL (0.4 pg/assay) in the absence of urine sample. The overall analytical recoveries for T-2 toxin, HT-2, T-2-4ol, 3'-OH-HT-2, NEOS, and a mixture of these 5 toxins added to the urine samples in the ELISA at concentrations of 0.05 and 0.2 ng/mL were 87 and 94%, respectively.     

A new LC/MS/MS rapid and sensitive method for the determination of green tea catechins and their metabolites in biological samples

A new rapid and sensitive method has been developed, using liquid chromatography in tandem mass spectrometry (LC-ESI-MS/MS) to identify green tea catechin metabolites in plasma and urine after oral intake of a green tea extract. (-)-Epigallocatechin-3-gallate (EGCG), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC)-glucuronide, (-)-epicatechin (EC)-glucuronide, and EC-sulfate were identified in plasma, whereas in urine only the conjugated catechins were detected (EGC-glucuronide, EGC-sulfate, EC-glucuronide, and EC-sulfate). Standard calibration curves prepared in plasma were found to be linear in the range of 10.9-1379.3 nmol/L for EGCG, EGC, ECG, and EC. The accuracy and precision of this assay showed a coefficient of variation of <15%. The method allowed the detection and quantification limits (for 20 microL injection) from 1.1 to 2.6 nmol/L and 3.8-8.7 nmol/L, respectively, in plasma and 0.8-1.8 nmol/L and 2.6-6.0 nmol/L, respectively, in urine. This method can be applied for future clinical and epidemiological studies, allowing the identification of the active metabolites that will reach the target tissues.     

High pressure liquid chromatography of zearalenone and zearalenols in rat urine and liver

A high pressure liquid chromatographic technique with internal standardization has been developed for determining zearalenone and metabolites in rat urine and liver. Following extraction with methylene chloride and solvent partition, samples are cleaned up by applying the extract to a Sephadex LH-20 column and eluting with a mixture of benzene-methanol (85 + 15). Compounds were resolved on 2 Part-isil-10 columns (25 cm x 4.6 mm id) in series with a mobile phase of isooctane-chloroform-methanol (35 + 25 + 3), and detected at 280 nm. The internal standard was 6'alpha-acetoxyzearalane. Limits of detection were about 2.0 ng for zearalenone and 5.0 ng for zearalenols (6'-hydroxyzearalane). Zearalenone and zearalenols were excreted mainly in free form with relatively little glucuronide conjugation. Metabolism of zearalenone to free zearalenol was minor compared with formation of bound forms.     

Identification of metabolites of (-)-epicatechin gallate and their metabolic fate in the rat

After intravenous administration of (-)-epicatechin gallate to Wistar male rats, its biliary metabolites were examined. Deconjugated forms of (-)-epicatechin gallate metabolites were prepared by beta-glucuronidase/sulfatase treatment and purified by HPLC. Five compounds were subjected to FAB-MS and NMR analyses. These metabolites were shown to be (-)-epicatechin gallate, 3'-O-methyl-(-)-epicatechin gallate, 4'-O-methyl-(-)-epicatechin gallate, 4' '-O-methyl-(-)-epicatechin gallate, and 3',4' '-di-O-methyl-(-)-epicatechin gallate. After oral administration, five major metabolites excreted in rat urine were purified in their deconjugated forms and their chemical structures identified. They were degradation products from (-)-epicatechin gallate, pyrogallol, 5-(3,4-dihydroxyphenyl)-gamma-valerolactone, 4-hydroxy-5-(3,4-dihydroxyphenyl)valeric acid, 3-(3-hydroxyphenyl)propionic acid, and m-coumaric acid. Time course analysis of the identified (-)-epicatechin gallate metabolites showed that (-)-epicatechin gallate and its conjugate appeared in the plasma with their highest levels 0.5 h after oral administration; their levels rapidly decreased, and then they disappeared by 6 h. The degradation products, mainly in their conjugated forms, emerged at 6 h, peaked at 24 h, and disappeared by 48 h. In urine samples, (-)-epicatechin gallate and its methylated metabolites were hardly detected and the degradation products began to be excreted in the 6-24 h period, peaked in the 24-48 h period, and then began to disappear. The most abundant metabolite in both the plasma and the urine was found to be the conjugated form of pyrogallol. On the basis of these results, a possible metabolic route of (-)-epicatechin gallate orally administered to the rat is proposed.     

Identification of rat urinary and fecal metabolites of a new herbicide, pyribenzoxim

Rats were treated with pyribenzoxim (O-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime), a new herbicide, to investigate the related metabolites in urine and feces. Metabolites were identified using LC/MS (electrospray ionization) and GC/MS (electron impact ionization) following the relatively simple and rapid extraction and purification procedures. Three metabolites were identified in urine either from oral gavage or intravenous (iv) injection. They were benzophenone oxime (BO), benzophenone oxime glucuronide (BOG), and 2-hydroxy-6-(4,6-dimethoxypyrimidin-2-yloxy)benzoic acid (HDB). Benzophenone oxime was present in larger quantity than BOG and HDB in urine from oral treatment, while the case was opposite in urine from iv treatment. Glucuronide conjugate was confirmed unambiguously by enzyme hydrolysis. 2,6-Bis(4,6-dimethoxypyrimidin-2-yloxy)benzoic acid (KIH-2023) and benzophenone were identified in feces. Benzophenone was confirmed by GC/MS and HPLC/DAD since LC/MS could not produce an ESI spectrum. On the basis of the results obtained, a metabolic map of pyribenzoxim is proposed.     

Rapid liquid chromatography tandem mass spectrometry assay to quantify plasma (-)-epicatechin metabolites after ingestion of a standard portion of cocoa beverage in humans

A rapid liquid chromatography electrospray ionization tandem mass spectrometry with negative ion detection method was developed and validated to determine cocoa flavonoid metabolites in human plasma and urine after the intake of a standard portion of a cocoa beverage. A chromatographic run time of only 9 min provided clear separation of all metabolites and internal standards. Samples were analyzed in a product-ion scan of m/z 289, 369, and 465 to identify the metabolites and in multiple reaction monitoring acquisition mode to quantify (-)-epicatechin ((-)-Ec) (289/ 245), (-)-epicatechin-glucuronide ((-)-EcG) (465/289), and (-)-epicatechin-sulfate ((-)-EcS) (369/289). One (-)-Ec-G and three (-)-Ec-S were identified and confirmed in urine as the major metabolites, and one (-)-Ec-G was the only metabolite present in plasma volunteers (n = 5) at a mean concentration of 625.7 +/- 198.3 nmol/L at 2 h after consumption of a cocoa beverage containing 54.4 mg of (-)-Ec.     

Anthocyanins from maize (Zea mays) and reed canarygrass (Phalaris arundinacea)

Flowers of maize, Zea mays, and reed canarygrass, Phalaris arundinacea, contain the same anthocyanins: cyanidin 3-glucoside, cyanidin 3-(6' '-malonylglucoside), cyanidin 3-(3' ',6' '-dimalonylglucoside), peonidin 3-glucoside, peonidin 3-(6' '-malonylglucoside), and peonidin 3-(dimalonylglucoside). The latter pigment has previously not been reported to occur in plants. Structure elucidations were primarily based on homo- and heteronuclear two-dimensional NMR and electrospray MS. During the isolation procedure using various mixtures of H(2)O, CF(3)CO(2)H, and CH(3)OH, and during storage in NMR solvent (CF(3)CO(2)D/CD(3)OD; 1:19, v/v) methyl esterification of the free acid function of the malonyl units of the pigments occurs. The acylated anthocyanins constitute more than 80% and 40% of the anthocyanins in P. arundinacea and Z. mays, respectively. Flowers and leaves of maize, Zea mays, contain the same anthocyanins in nearly equal relative proportions.