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PubMed1996

A New Type of Heterobimetallic Compound Containing Tungstenocene: Synthesis, Reactivity, NMR, and Stereochemical Studies.

Reaction of [PPh(2)M(CO)(5)]Li salts (M = Cr or W) toward tungstenocene dichloride occurs via a cyclopentadienyl ring substitution and yields the corresponding binuclear compounds (eta(5)-C(5)H(5))[eta(5)-C(5)H(4)PPh(2)M(CO)(5)]W(H)Cl, 2. They react with LiAlH(4) to give the corresponding dihydride complexes (eta(5)-C(5)H(5))[eta(5)-C(5)H(4)PPh(2)M(CO)(5)]WH(2), 3. These species have been proven to be photosensitive leading to the cyclic heterobimetallic (eta(5)-C(5)H(5))[eta(5)-C(5)H(4)PPh(2)M(CO)(4)]W(&mgr;-H)H compounds, 4; analytical data and spectroscopic measurements on complexes 4 indicate that a hydride group functions as a bridging ligand. Crystals of 4a (M = Cr) were obtained as red needles, grown from toluene solution. An isotropic refinement of only 1243 data (F > 5sigma(F)) from a low resolution data set (3707 data, d(min) = 0.9 Å) indicated significant systematic error. Thus it was possible only to ascertain that the connectivity of the non-hydrogen atoms is not inconsistent with the model proposed from solution NMR and that the Cr.W separation of 3.30 Å precludes a direct Cr-W bond. 4a crystallizes in space group Pbca(No. 61), with a = 19.693(8) Å, b = 20.34(1) Å, c = 11.695(5) Å, V = 46823 Å(3), and Z = 8. Further information on this preliminary structure determination is provided in the Supporting Information. These reactions have been investigated with stereochemical factors in mind using the ring substituted tungtenocene complex (eta(5)-C(5)H(4)Me)(2)WCl(2); the 1-3 regioselectivity of the ring disubstitution reaction is proposed on the basis of (1)H NMR experiments. The temperature dependent relaxation time measured between 295 and 213 K by the inversion recovery method makes it possible to determine a proton-proton distance between the two H ligands of 2.0 Å in 4'a.

Journal Article↗
PubMed1997

Synthesis, Characterization, and Reactivity of Group 12 Metal Thiocarboxylates, M(SOCR)(2)Lut(2) [M = Cd, Zn; R = CH(3), C(CH(3))(3); Lut = 3,5-Dimethylpyridine (Lutidine)].

A series of group 12 metal thiocarboxylate species, M(SOCR)(2)Lut(2) [M = Cd, Zn; R = CH(3), C(CH(3))(3); Lut = 3,5-dimethylpyridine (lutidine)], were synthesized to investigate their potential to act as precursors for the formation of metal sulfide materials. These species were expected to undergo thiocarboxylic anhydride elimination to give stoichiometric metal sulfides and remove the organic supporting ligands cleanly. These species were characterized by (1)H, (13)C, and (where appropriate) (113)Cd NMR spectroscopies, TGA, elemental analysis, and single-crystal X-ray diffraction. The spectroscopic and analytical data were consistent with the formulas identified above, and in the solid state the compounds are monomeric with approximate tetrahedral metal coordination environments and monodentate S-bond thiocarboxylate ligands. Crystal data for Cd(SOCCH(3))(2)Lut(2): crystallized in the triclinic space group P&onemacr;, with a = 8.267(1) Å, b = 9.467(1) Å, c = 14.087(1) Å, alpha = 94.04(1) degrees, beta = 91.49(1) degrees, gamma = 104.03(1) degrees, and Z = 2. Thermal decomposition of these compounds in the solid state or in solution resulted in formation of the corresponding metal sulfide at low temperatures, as seen by powder X-ray diffraction. Evidence for thiocarboxylic anhydride elimination was documented by NMR in solution phase reactions. The effects on thiocarboxylic anhydride elimination, resulting from varying M, R, or solvent media, were examined by heating NMR tube solutions of M(SOCR)(2)Lut(2) in pyridine or toluene. Heating toluene or pyridine solutions of Cd(SOCCH(3))(2)Lut(2) resulted in formation of nanocrystalline, sphalerite CdS, as determined by X-ray diffraction and TEM. These preliminary reactivity studies have revealed the great potential of this highly tailorable chemical system as precursors to group 12 metal sulfido species.

Journal Article↗
PubMed1997

Synthesis, Characterization, and Reactivity of Isocyanato Dicarbaboranes Obtained from o-Carborane.

The functionalization of o-carborane with (bromoalkyl)phthalimides or propargylphthalimide, their subsequent transformation into isocyanate-substituted o-carborane, and their reactivity toward amino- and alcohol-containing molecules are reported. The preparation of these functionalized ureas and carbamates could potentially lead to the utilization of these molecules as suitable precursors for drugs to be used in boron neutron capture therapy (BNCT). The compounds 1-RNHC(O)NH(CH(2))(n)()-1,2-C(2)B(10)H(11) and 1-ROC(O)NH-1,2-C(2)B(10)H(11) (n = 1, 2, and 3) were prepared by reaction of 1-O=C=N(CH(2))(n)()-1,2-C(2)B(10)H(11), (n = 1, 2, and 3) with the corresponding amino- or alcohol-containing substrate. Experimental details and analytical data leading to the identification of the reported compounds are provided. Additionally the X-ray diffraction structures of 1-C(6)H(4)(CO)(2)NCH(2)CH(2)CH(2)-1,2-C(2)B(10)H(11) (1c) and 1-(C(6)H(5))(2)C=N-CH(2)-1,2-C(2)B(10)H(11) (20) are reported. Compound 1c crystallizes in the P&onemacr; space group, a = 10.791(1) Å, b = 13.104(1) Å, c = 7.1816(9) Å, alpha = 97.389(8) degrees, beta = 90.416(5) degrees, gamma = 66.462(6) degrees, Z = 2, R = 0.0512 for 2140 reflections with F(2) > 3.0sigma(F(2)). Compound 20 crystallizes in the P2(1)/n space group, a = 16.5560(7) Å, b = 7.0173(4) Å, c = 16.9750(6) Å, beta = 97.932(2) degrees, Z = 4, R = 0.0843 for 2755 reflections with F > 4.0sigma(F).

Journal Article↗
PubMed1999

Synthesis, Structure, Biological Activity, and DNA Binding of Platinum(II) Complexes of the Type trans-[PtCl(2)(NH(3))L] (L = Planar Nitrogen Base). Effect of L and Cis/Trans Isomerism on Sequence Specificity and Unwinding Properties Observed in Globally Platinated DNA.

In order to establish fundamental structural requirements for the antitumor activation of the trans-platinum geometry, complexes of the general formulas [PtCl(2)(NH(3))L] (L = planar N donor) have been synthesized. The trans isomers, trans-[PtCl(2)(NH(3))(quinoline)] (3), trans-[PtCl(2)(NH(3))(thiazole)] (5), trans-[PtCl(2)(NH(3))(benzothiazole)] (7), and trans-[PtCl(2)(NH(3))(isoquinoline)] (8) and the cis isomers cis-[PtCl(2)(NH(3))(quinoline)] (4) and cis-[PtCl(2)(NH(3))(thiazole)] (6) were characterized by (1)H NMR and analytical data. In addition, the crystal structures of 3, 5, 7, and 8 were determined: 3, monoclinic, P2(1)/c, with a = 8.414(1) Å, b = 12.373(3) Å, c = 21.266(3) Å, beta = 96.78(1) degrees, V = 2198.3(6) Å(3), and Z = 8; 5, monoclinic, P2(1)/n, with a = 8.815(4) Å, b = 19.917(8) Å, c = 14.498(5) Å, beta = 103.30(3) degrees, V = 2477(2) Å(3), and Z = 12; 7, monoclinic, P2(1)/c, with a = 8.150(4) Å, b = 23.196(9) Å, c = 11.297(7) Å, beta = 90.94(4) degrees, V = 2135.3(2) Å(3), and Z = 8; 8, monoclinic, C2/c, with a = 19.043(4) Å, b = 8.570(2) Å, c = 29.127(6) Å, beta_ = 111.59(2) degrees, V = 4420(2) Å(3), and Z = 16. In all cases, the Pt coordination plane and L are mutually twisted with angles between planes of 50-68 degrees. Bulky quinoline in 3 produces intramolecular steric strain as evidenced by a short, nonbonding Pt.H8(quin) contact of 2.77 Å and concomitantly distorted Pt-N(quin)-C bond angles. The trans complexes 3, 5, 7, and 8 showed a significantly higher cytotoxicity in cisplatin-sensitive L1210 leukemia than trans-[PtCl(2)(NH(3))(2)] (2), with 3 and 5 being as potent as the corresponding cis isomers 4 and 6. In addition, the presence of the planar ligand greatly enhanced the activity of all of the compounds in cells resistant to cisplatin, cis-[PtCl(2)(NH(3))(2)] (1). Complex geometry and L play an important role in the binding of 1-7 to DNA. For synthetic poly(dG).poly(dC) and poly(dG-dC).poly(dG-dC) the order of binding affinities (r(b), drug-to-nucleotide ratio) was 2 > 1 > 6 > 5 > 4 > 7 > 3 and 5 > 6 > 7 > 3 > 2 > 1 > 4, respectively. Furthermore, 3 and 7, carrying large planar ligands, were remarkably effective at unwinding negatively supercoiled, closed circular pUC19 DNA (phi = 15 degrees and 17 degrees, respectively). The consequences of structural effects caused by L on target DNA with respect to possible biological consequences are discussed.

Journal Article↗
PubMed1999

Coupling of Amino Carboranes to Carboxylic Acid Containing Substrates.

The reactivity of the known amino carboranes 1-H(2)NCH(2)-1,2-C(2)B(10)H(11) and 7-H(3)N-7-CB(10)H(12) with carboxylic acid containing substrates was investigated. The reactions studied using the coupling reagent, 1,1'-carbonyldiimidazole, resulted in the preparation of a series of amides in moderate to high yield. The relative importance of this type of research resides in the fact that it allows the introduction of amino acids in close contact with the carborane cage. These compounds can constitute a new generation of substrates useful in boron neutron capture therapy. Our emphasis lies in the development of suitable synthetic schemes allowing the preparation of this type of compound. Experimental details and analytical data supporting the formulation of the prepared compounds are reported.

Journal Article↗
PubMed2002

Total syntheses of the phytotoxic lactones herbarumin I and II and a synthesis-based solution of the pinolidoxin puzzle.

A concise approach to a family of potent herbicidal 10-membered lactones is described on the basis of ring-closing metathesis (RCM) as the key step for the formation of the medium-sized ring. This includes the first total syntheses of herbarumin I (1) and II (2) as well as the synthesis of several possible macrolides of the pinolidoxin series. A comparison of their spectral and analytical data with those of the natural product allowed us to establish the stereostructure of pinolidoxin, a potent inhibitor of induced phenylalanine ammonia lyase (PAL) activity, as shown in 46. This finding, however, makes clear that a previous study dealing with the relative and absolute stereochemistry of this phytotoxic agent cannot be correct. An important aspect from the preparative point of view is the fact that the stereochemical outcome of the RCM reaction can be controlled by the choice of the catalyst. Thus, use of the ruthenium indenylidene complex 16 always leads to the corresponding (E)-alkenes, whereas the second generation catalyst 17 bearing an N-heterocyclic carbene ligand affords the isomeric (Z)-olefin with good selectivity. This course is deemed to reflect kinetic versus thermodynamic control of the cyclization reaction and therefore has potentially broader ramifications for the synthesis of medium-sized rings in general. A further noteworthy design feature is the fact that D-ribose is used as a convenient starting material for the preparation of both enantiomers of the key building block 14 by means of a "head-to-tail" interconversion strategy.

Alkenes↗
PubMed2002

Analysis of acrylamide, a carcinogen formed in heated foodstuffs.

Reaction products (adducts) of acrylamide with N termini of hemoglobin (Hb) are regularly observed in persons without known exposure. The average Hb adduct level measured in Swedish adults is preliminarily estimated to correspond to a daily intake approaching 100 microg of acrylamide. Because this uptake rate could be associated with a considerable cancer risk, it was considered important to identify its origin. It was hypothesized that acrylamide was formed at elevated temperatures in cooking, which was indicated in earlier studies of rats fed fried animal feed. This paper reports the analysis of acrylamide formed during heating of different human foodstuffs. Acrylamide levels in foodstuffs were analyzed by an improved gas chromatographic-mass spectrometric (GC-MS) method after bromination of acrylamide and by a new method for measurement of the underivatized acrylamide by liquid chromatography-mass spectrometry (LC-MS), using the MS/MS mode. For both methods the reproducibility, given as coefficient of variation, was approximately 5%, and the recovery close to 100%. For the GC-MS method the achieved detection level of acrylamide was 5 microg/kg and for the LC-MS/MS method, 10 microg/kg. The analytic values obtained with the LC-MS/MS method were 0.99 (0.95-1.04; 95% confidence interval) of the GC-MS values. The LC-MS/MS method is simpler and preferable for most routine analyses. Taken together, the various analytic data should be considered as proof of the identity of acrylamide. Studies with laboratory-heated foods revealed a temperature dependence of acrylamide formation. Moderate levels of acrylamide (5-50 microg/kg) were measured in heated protein-rich foods and higher contents (150-4000 microg/kg) in carbohydrate-rich foods, such as potato, beetroot, and also certain heated commercial potato products and crispbread. Acrylamide could not be detected in unheated control or boiled foods (<5 microg/kg). Consumption habits indicate that the acrylamide levels in the studied heated foods could lead to a daily intake of a few tens of micrograms.

Acrylamide↗
PubMed2002

Chemometrical analysis of 18 metallic and nonmetallic elements found in honeys sold in france.

The elemental analysis of 86 honeys sold in France was performed with an inductively coupled plasma atomic emission spectrometer in order to measure significant concentrations of Ag, Ca, Cr, Co, Cu, Fe, Li, Mg, Mn, Mo, P, S, Zn, Al, Cd, Hg, Ni, and Pb. Principal component analysis, correspondence factor analysis, and hierarchical cluster analysis were used to rationalize and interpret the analytical data. Crude relationships were found between the elemental profiles of the honeys and their botanical origin. Some honeys were highly polluted by heavy metals and/or other xenobiotics. Explanations for these contaminations are proposed.

Analysis of Variance↗
PubMed2003

Speciation of selenium compounds from high selenium broccoli is affected by the extracting solution.

The speciation of selenium compounds from high selenium broccoli (876 microg/g) depends on the extraction conditions. Twenty-seven extraction conditions were explored involving nine different buffering systems between pH 1 and pH 9. In nonbuffered extractions of broccoli, more than 40% of the spiked Se-methylselenocysteine was not recovered in the filtered solution. However, in buffered extractions, losses for Se-methylselenocysteine ranged from 10 to 20%. Mass balance indicated that approximately 30% of naturally occurring selenium in broccoli samples was volatilized and lost to the atmosphere when buffered extractions were made. Solid phase extractions indicated that the polarity of selenium compounds in solution was also dependent on the extracting solution. High-pressure liquid chromatography coupled to an inductively coupled plasma mass spectrometer was used to show that selenium compounds extracted from broccoli reacted with the extracting solution. Compound identities were assigned by matching retention times to standards of selenite, selenate, methylseleninic acid, Se-methylselenocysteine, selenomethionine, and the selenonic acids of Se-methylselenocysteine and selenomethionine. Changes in speciation were analyte-, pH-, and buffer-dependent, but generally, a higher pH resulted in more highly oxidized selenium compounds. For valid conclusions to be drawn from the analytical data, the extraction conditions should match the conditions present in the matrix or be specified for a particular application such as a simulated gastrointestinal digestion.

Brassica↗
PubMed2004

Investigation of potent odorants and afterodor development in two Chardonnay wines using the buccal odor screening system (BOSS).

Potent odorants of two Chardonnay wines were characterized according to their specific overall aroma profiles and their intraoral release patterns after wine consumption. Therefore, aroma compounds were isolated and analyzed by means of high resolution gas chromatography-olfactometry (HRGC/O), leading to the detection of 36 odor-active compounds in both wines. All compounds were identified. Of the most potent odorants, 25 were quantified in both wines by means of stable isotope dilution assays. For the intraoral investigation of odor compounds at defined times after Chardonnay wine consumption, the recently developed buccal odor screening system was used. Significant differences in the oral persistence of characteristic odor notes were observed for both wines with mainly the characteristic barrique-notes being highly persistent, while fruity notes quickly disappeared from the oral cavity. The obtained analytical data were related to time-resolved retronasal aroma evaluation.

Chromatography, Gas↗
PubMed2005

Enantioselective synthesis of the female sex pheromone of the pink hibiscus Mealybug, Maconellicoccus hirsutus.

The pink hibiscus mealybug, Maconellicoccus hirsutus (Green), is an exotic insect pest and recently invaded Southern California and Florida. The female M. hirsutus releases the 2-methylbutanoate of a novel cyclobutanoid monoterpene alcohol (maconelliol) that together with lavandulyl 2-methylbutanoate constitutes the sex pheromone to attract males from a distance. Enantioselective syntheses of four different stereoisomers of the major component, maconelliyl 2-methylbutanoate 1, from alpha-pinene are reported. Absolute configurations of both naturally occurring maconelliyl 2-methylbutanoate 1 and the minor component, lavandulyl 2-methylbutanoate 2, have been established. Comparison of the analytical data of naturally occurring compounds with those of optically active synthetic isomers proved that both esters show the (R)-configuration at the alcohol and the (S)-configuration at acid moieties.

Animals↗
PubMed2005

Investigation of the retronasal perception of strawberry aroma aftersmell depending on matrix composition.

The development of strawberry aroma aftersmell after consumption in aqueous and milk model systems was followed. A recently developed sensory approach was used to seize the qualitative, quantitative, and temporal aspects of aroma profile development. The results obtained from sensory evaluation were then correlated to analytical data, obtained by means of intraoral aroma detection using the buccal odor screening system (BOSS). A clear correlation was found between the sensory persistence of single odor impressions and the intraoral detectability of odorants by BOSS. For the strawberry aroma mixture it could be shown that BOSS is capable of selecting those odorants of a complex aroma mixture that elicit a certain aftersmell impression developing after a certain period of time in the oral cavity. Also, the changes in in vivo odorant persistence depending on changes in food matrix composition could be directly followed by means of BOSS.

Cheek↗
PubMed2004

Essential oils of Satureja, Origanum, and Thymus species: chemical composition and antibacterial activities against foodborne pathogens.

The chemical composition of the essential oils obtained from the species restricted to Greece and the eastern Mediterranean region, Satureja spinosa L. and Thymus longicaulis L.; species endemic to central and south Greece, Satureja parnassica ssp. parnassica Heldr. and Sart ex Boiss.; species endemic to the island of Crete, Origanum dictamnus L.; and species widely distributed in the Mediterranean region, Satureja thymbra L. and Origanum vulgare L. subsp. hirtum, were determined by gas chromatography (GC) and GC/mass spectrometry (MS) analysis. The in vitro antibacterial activities of the essential oils were evaluated against a panel of five foodborne bacteria (Escherichia coli 0157:H7 NCTC 12900, Salmonella enteritidis PT4, Staphylococcus aureus ATCC 6538, Listeria monocytogenes ScottA, and Bacillus cereus FSS 134). The analytical data indicated that various monoterpene hydrocarbons and phenolic monoterpenes constitute the major components of the oils, but their concentrations varied greatly among the oils examined. The antibacterial assay results showed that 5 muL doses of the essential oils extracted from the endemic Satureja species in Greece possess remarkable bactericidal properties, which are clearly superior as compared to those of Origanum and Thymus species essential oils. Therefore, they represent an inexpensive source of natural mixtures of antibacterial compounds that exhibit potentials for use in food systems to prevent the growth of foodborne bacteria and extend the shelf life of the processed food.

Anti-Bacterial Agents↗
PubMed2004

Characterization of carrot root oil arising from supercritical fluid carbon dioxide extraction.

Carrot root oil (SCO), obtained by supercritical fluid carbon dioxide (SC-CO2) extraction, was characterized and compared to a commercial carrot oil (MCO) and a virgin olive oil (VOO) (cv. Coratina). SCO showed much higher contents of carotenes, phenolics, waxes, phytosterols, and sesquiterpene and monoterpene volatiles. In SCO, the most prominent components present in the fully investigated analytical fractions (fatty acids, triglycerides, waxes, phytosterols, long-chain aliphatic alcohols, superior triterpene alcohols, and volatiles) were, respectively, linolenic acid, trilinolein, waxes C38, beta-sitosterol, campesterol and stigmasterol, 1-hexacosanol, 24-methylencycloartanol and cycloartenol, beta-caryophyllene, alpha-humulene, alpha-pinene, and sabinene. In VOO, the major constituents of the above analytical classes were, respectively, oleic acid, trilinolein, waxes C36, unsaturated volatile C6 aldehydes (trans-2-hexenal most markedly), and the same prominent sterols and superior alcohols found in SCO. In MCO, which also contained a proportion of unknown plant oil, several components showed magnitudes that were lower compared to SCO but higher with respect to VOO. The last had the aliphatic and triterpene alcohol concentration higher compared to that of both SCO and MCO. Several chemometric methods, applied to different analytical data sets, proved to be effective in grouping the three oil kinds.

Chromatography, Supercritical Fluid↗
PubMed2006

Factors affecting the contents of iridoid oleuropein in olive leaves (Olea europaea L.).

In this study, for the first time, the impact of the genetic factor on the contents of oleuropein in olive leaves was not only evaluated but the influence exerted by the color/age of leaves (green, green-yellowish, and yellow) and the collecting period (spring or autumn) was also evaluated. A repetitive high-resolution gas chromatographic quantitation method and an accurate high-performance liquid chromatographic method were developed. These analytical methods gave results showing a highly linear relationship. Samples of olive leaves were taken from seven major Italian olive cultivars, such as Dritta, Leccino, Caroleo, Coratina, Castiglionese, Nebbio, and Grossa di Cassano. Such a vegetal raw material could actually be exploited for recovering oleuropein, considered to be a high-added value molecule. This could be converted into hydrxytyrosol, a compound known to possess strong bioactive properties. Olive leaves showed considerable contents of oleuropein, which with some cultivars were even higher with respect to those present in the corresponding olive fruits (reported in the literature). The amounts of oleuropein in the collected leaves were markedly modified by the color/age and genetic factors, whereas meaningless variations were ascribable to the quantitation method and the collecting period factors. Various chemometrics, applied to the obtained analytical data, appeared to be effective in discriminating the samples on the basis of the above-examined experimental factors, thus confirming how these should be taken into account in future industrial recovery of oleuropein from olive leaves.

Analysis of Variance↗
PubMed2006

Microclimate influence on mineral and metabolic profiles of grape berries.

The grape berry microclimate is known to influence berry quality. The effects of the light exposure of grape berry clusters on the composition of berry tissues were studied on the "Merlot" variety grown in a vineyard in Bordeaux, France. The light exposure of the fruiting zone was modified using different intensities of leaf removal, cluster position relative to azimuth, and berry position in the cluster. Light exposures were identified and classified by in situ measurements of berry temperatures. Berries were sampled at maturity (>19 Brix) for determination of skin and/or pulp chemical and metabolic profiles based on (1) chemical and physicochemical measurement of minerals (N, P, K, Ca, Mg), (2) untargeted 1H NMR metabolic fingerprints, and HPLC targeted analyses of (3) amino acids and (4) phenolics. Each profile defined by partial least-square discriminant analysis allowed us to discriminate berries from different light exposure. Discriminant compounds between shaded and light-exposed berries were quercetin-3-glucoside, kaempferol-3-glucoside, myricetin-3-glucoside, and isorhamnetin-3-glucoside for the phenolics, histidine, valine, GABA, alanine, and arginine for the amino acids, and malate for the organic acids. Capacities of the different profiling techniques to discriminate berries were compared. Although the proportion of explained variance from the 1H NMR fingerprint was lower compared to that of chemical measurements, NMR spectroscopy allowed us to identify lit and shaded berries. Light exposure of berries increased the skin and pulp flavonols, histidine and valine contents, and reduced the organic acids, GABA, and alanine contents. All the targeted and nontargeted analytical data sets used made it possible to discriminate sun-exposed and shaded berries. The skin phenolics pattern was the most discriminating and allowed us to sort sun from shade berries. These metabolite classes can be used to qualify berries collected in an undetermined environment. The physiological significance of light and temperature effects on berry composition is discussed.

Amino Acids↗
PubMed2006

Flavonoid content of U.S. fruits, vegetables, and nuts.

Analytical data are reported for 20 flavonoids (as aglycones) determined for more than 60 fresh fruits, vegetables, and nuts collected from four regions across the United States at two times of the year. Sample collection was designed and implemented by the Nutrient Data Laboratory (USDA). Analyses of eight flavan-3-ols (catechin, catechin gallate, epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, gallocatechin, and gallocatechin gallate), six anthocyanins (cyanidin, delphinidin, malvidin, pelargonidin, peonidin, and petunidin), two flavanones (hesperetin and naringenin), two flavones (apigenin and luteolin), and two flavonols (myricetin and quercetin) were performed by the Food Composition Laboratory (USDA) using a hydrolysis method for the anthocyanidins, flavones, and flavonols and a direct extraction method for the flavan-3-ols and flavanones. Experimental results compare favorably (few statistically significant differences) to literature values in the flavonoid and proanthocyanidin database previously compiled by the Nutrient Data Laboratory. The results of this study showed a seasonal variation only for blueberries. This study also showed that the variation in the flavonoid content of foods, as purchased by the U.S. consumer, is very large. The relative standard deviation, averaged for each flavonoid in each food, was 168%.

Flavonoids↗
PubMed1999

Analytical characterization of madeira wine.

For a correct characterization of Madeira wine commercially available in the market, 52 samples having different types and ages, representative of the delimited region of Madeira (liquor wine of quality produced in delimited region), were analyzed in relation to physicochemical and sensorial parameters. Standard methodology for spirits and alcoholic beverages as well as a council of tasters were adopted respectively to quantify such parameters, according to European Union regulations. The main physicochemical parameters analyzed demonstrated that Madeira wine represent a high quality beverage without toxicological risks, as all constituents have in general contents clearly below the maximum concentration admissible by the national and/or international rules. A reasonable differentiation of properties could be achieved between samples having different types and ages, when principal component, discriminant and cluster analyses were applied to the analytical data, especially for physicochemical parameters.

Chemical Phenomena↗