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ABSTRACT: Chamomile (Matricaria chamomilla L.), tarragon (Artemisia dracunculus L.) and Mexican arnica (Heterotheca inuoides) are common compositae spices and herbs found in the US market. They contain flavonoids and hydroxycinnamates that are potentially beneficial to human health. A standardized LC-PDA-ESI/MS profiling method was used to identify 51 flavonoids and 17 hydroxycinnamates. Many of the identifications were confirmed with authentic standards or through references in the literature or the laboratory's database. More than half of the phenol compounds for each spice had not been previously reported. The phenolic profile can be used for plant authentication and to correlate with biological activities.
Natural product communications 06/2012; 7(6):749-52. · 1.24 Impact Factor
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ABSTRACT: Traditionally, anthocyanin analysis in mass spectrometry is carried out in the positive ionization mode only. A study of the mass spectrometric behaviors of anthocyanins in the negative ionization mode revealed interesting characteristics that was not previously reported. It can be used to differentiate anthocyanins from other non-anthocyanin polyphenols.
An ultra-high-performance liquid chromatography with high-resolution mass spectrometry (U-HPLC/HRMS) method was developed. The method used multiple-stage mass fragmentation in both the negative and positive ion modes. The whole cycle time of the new method is 1.8 s for two full scans and six data-dependent scans.
The new strategy found, in the negative ionization mode, a series of characteristic ions, e.g. [M-2H](-), [M-2H + H(2)O](-), formic acid adducts, and doubly charged ions were observed for the MS analysis of anthocyanins. The characteristic ions can be used for identification and differentiation of anthocyanins and non-anthocyanin phenolic compounds. Comprehensive studies were performed on the differentiation of anthocyanins and non-anthocyanin polyphenols in blueberry (Vaccinium cyanococcus), Hongcaitai (Brassica compestris L. var. purpurea Bailey), and red radish (Raphanus sativus var. longipinnatus 'Shinrimei').
The data generated from a single LC run enables rapid and reliable differentiation and identification of anthocyanins and non-anthocyanins in botanicals and foods. Published 2012. This article is a US Government work and is in the public domain in the USA.
Rapid Communications in Mass Spectrometry 05/2012; 26(9):1123-33. · 2.79 Impact Factor
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ABSTRACT: An UHPLC-PDA-ESI/HRMS/MS(n) profiling method was used for a comprehensive study of the phenolic components of red mustard greens ( Brassica juncea Coss variety) and identified 67 anthocyanins, 102 flavonol glycosides, and 40 hydroxycinnamic acid derivatives. The glycosylation patterns of the flavonoids were assigned on the basis of direct comparison of the parent flavonoid glycosides with reference compounds. The putative identifications were obtained from tandem mass data analysis and confirmed by the retention time, elution order, and UV-vis and high-resolution mass spectra. Further identifications were made by comparing the UHPLC-PDA-ESI/HRMS/MS(n) data with those of reference compounds in the polyphenol database and in the literature. Twenty-seven acylated cyanidin 3-sophoroside-5-diglucosides, 24 acylated cyanidin 3-sophoroside-5-glucosides, 3 acylated cyanidin triglucoside-5-glucosides, 37 flavonol glycosides, and 10 hydroxycinnamic acid derivatives were detected for the first time in brassica vegetables. At least 50 of them are reported for the first time in any plant materials.
Journal of Agricultural and Food Chemistry 11/2011; 59(22):12059-72. · 2.82 Impact Factor
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ABSTRACT: An LC-PDA-ESI/MS(n) profiling method was used to identify the anthocyanins of purple Bordeaux radish and led to the assignment of 60 anthocyanins: 14 acylated cyanidin 3-(glucosylacyl)acylsophoroside-5-diglucosides, 24 acylated cyanidin 3-sophoroside-5-diglucosides, and 22 acylated cyanidin 3-sophoroside-5-glucosides. The identifications were supported by the presence of 3-sophoroside-5-diglucoside and 3-sophroside-5-glucoside of cyanidin in the alkaline-hydrolyzed extract. A reliable method to identify the anthocyanins containing 3-(glucosylacyl)acylsophorosyl functions is described. The tentative identifications were obtained from tandem mass data analysis and confirmed by high-resolution mass measurements. Further assignments were made for some anthocyanins from a comparison of the mass and UV-vis data and elution order with those of the anthocyanins in the authors' polyphenol database and from consideration of the structural characteristics of the anthocyanins from similar plants and similar anthocyanins in the literature. The presence of 38 acylated cyanidin 3-sophoroside-5-diglucosides and around 10 acylated cyanidin 3-sophoroside-5-malonylglucosides in plants is reported here for the first time.
Journal of Agricultural and Food Chemistry 06/2011; 59(12):6616-27. · 2.82 Impact Factor
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ABSTRACT: Spectral fingerprinting, as a method of discriminating between plant cultivars and growing treatments for a common set of broccoli samples, was compared for six analytical instruments. Spectra were acquired for finely powdered solid samples using Fourier transform infrared (FT-IR) and Fourier transform near-infrared (NIR) spectrometry. Spectra were also acquired for unfractionated aqueous methanol extracts of the powders using molecular absorption in the ultraviolet (UV) and visible (VIS) regions and mass spectrometry with negative (MS-) and positive (MS+) ionization. The spectra were analyzed using nested one-way analysis of variance (ANOVA) and principal component analysis (PCA) to statistically evaluate the quality of discrimination. All six methods showed statistically significant differences between the cultivars and treatments. The significance of the statistical tests was improved by the judicious selection of spectral regions (IR and NIR), masses (MS+ and MS-), and derivatives (IR, NIR, UV, and VIS).
Applied Spectroscopy 03/2011; 65(3):250-9. · 1.66 Impact Factor
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ABSTRACT: A liquid chromatography-mass spectrometry (LC-MS) profiling method was used to characterize the phenolic components of 17 leafy vegetables from Brassica species other than Brassica oleracea. The vegetables studied were mustard green, baby mustard green, gai choy, baby gai choy, yu choy, yu choy tip, bok choy, bok choy tip, baby bok choy, bok choy sum, Taiwan bok choy, Shanghai bok choy, baby Shanghai bok choy, rapini broccoli, turnip green, napa, and baby napa. This work led to the tentative identification of 71 phenolic compounds consisting of kaempferol 3-O-diglucoside-7-O-glucoside derivatives, isorhamnetin 3-O-glucoside-7-O-glucoside hydroxycinnamoyl gentiobioses, hydroxycinnamoylmalic acids, and hydroxycinnamoylquinic acids. Ten of the compounds, 3-O-diacyltriglucoside-7-O-glucosides of kaempferol and quercetin, had not been previously reported. The phenolic component profiles of these vegetables were significantly different than those of the leafy vegetables from B. oleracea. This is the first comparative study of these leafy vegetables. Ten of the vegetables had never been previously studied by LC-MS.
Journal of Agricultural and Food Chemistry 06/2010; 58(11):6850-7. · 2.82 Impact Factor
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ABSTRACT: An LC-MS profiling method was used for a comprehensive study of the phenolic components of collard greens, kale, and Chinese broccoli, three Brassica green leafy vegetables. This study led to the identification of 45 flavonoids and 13 hydroxycinnamic acid derivatives in the three vegetables. Most of the identifications were based on comparison of compounds previously reported in the literature for Brassica vegetables. The results indicate that the three materials have very similar phenolic component profiles. For each, kaempferol glycosides and acylgentiobiosides were the major phenolic compounds, quercetin glycosides were minor compounds, and most of the flavononol glycosides existed in their acylated forms. In addition, each of the materials contained caffeoyl-, p-coumaroyl-, and feruloylquinic acid monomers with a 3-position derivative as the dominant isomer. This is the first report for most of these phenolics in collard greens and Chinese broccoli and for >20 of them in kale.
Journal of Agricultural and Food Chemistry 08/2009; 57(16):7401-8. · 2.82 Impact Factor
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ABSTRACT: Scutellaria lateriflora, commonly known as skullcap, is used as an ingredient in numerous herbal products. Unfortunately, it has occasionally been adulterated with Teucrium canadense or T. chamaedrys, commonly known as germander, which contains potentially hepatotoxic diterpenes. Chromatographic profiles of the phenolic components provide a means of distinguishing between these plants and enhancing public safety.
To develop a chromatographic method for the identification of Scutellaria lateriflora and two Teucrium species and to quantify the latter as adulterants.
Samples were extracted with aqueous methanol and the extracts were analysed using a standardised LC-DAD-ESI/MS profiling method to obtain their phenolic profiles.
Skullcap contained primarily flavonoids, while the major phenolic components of the two Teucrium species were the phenylethanoids, verbascoside and teucrioside. Using the phenylethanoids as markers, it was possible to clearly distinguish between the two genus and to determine 5% Teucrium mixed with Scutellaria using either ultraviolet absorption spectrometry or mass spectrometry in the total ion count mode. Using MS in the selective ion monitoring (SIM) mode, 1% Teucrium could be measured.
This study showed that chromatographic profiling was able to identify Scutellaria and Teucrium, separately and when mixed together.
Phytochemical Analysis 04/2009; 20(4):298-306. · 2.63 Impact Factor
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ABSTRACT: A screening method using LC-DAD-ESI/MS was developed for the identification of common hydroxycinnamoylquinic acids based on direct comparison with standards. A complete standard set for mono-, di-, and tricaffeoylquinic isomers was assembled from commercially available standards, positively identified compounds in common plants (artichokes, asparagus, coffee bean, honeysuckle flowers, sweet potato, and Vernonia amygdalina leaves) and chemically modified standards. Four C18 reversed phase columns were tested using the standardized profiling method (based on LC-DAD-ESI/MS) for 30 phenolic compounds, and their elution order and retention times were evaluated. Using only two columns under standardized LC condition and the collected phenolic compound database, it was possible to separate all of the hydroxycinnamoylquinic acid conjugates and to identify 28 and 18 hydroxycinnamoylquinic acids in arnica flowers (Arnica montana L.) and burdock roots (Arctium lappa L.), respectively. Of these, 22 are reported for the first time.
Journal of Agricultural and Food Chemistry 11/2008; 56(21):10105-14. · 2.82 Impact Factor
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ABSTRACT: Metabolite fingerprints, obtained with direct injection mass spectrometry (MS) with both positive and negative ionization, were used with analysis of variance-principal components analysis (ANOVA-PCA) to discriminate between cultivars and growing treatments of broccoli. The sample set consisted of two cultivars of broccoli, Majestic and Legacy, the first grown with four different levels of Se and the second grown organically and conventionally with two rates of irrigation. Chemical composition differences in the two cultivars and seven treatments produced patterns that were visually and statistically distinguishable using ANOVA-PCA. PCA loadings allowed identification of the molecular and fragment ions that provided the most significant chemical differences. A standardized profiling method for phenolic compounds showed that important discriminating ions were not phenolic compounds. The elution times of the discriminating ions and previous results suggest that they were common sugars and organic acids. ANOVA calculations of the positive and negative ionization MS fingerprints showed that 33% of the variance came from the cultivar, 59% from the growing treatment, and 8% from analytical uncertainty. Although the positive and negative ionization fingerprints differed significantly, there was no difference in the distribution of variance. High variance of individual masses with cultivars or growing treatment was correlated with high PCA loadings. The ANOVA data suggest that only variables with high variance for analytical uncertainty should be deleted. All other variables represent discriminating masses that allow separation of the samples with respect to cultivar and treatment.
Journal of Agricultural and Food Chemistry 11/2008; · 2.82 Impact Factor
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ABSTRACT: A standardized profiling method based on liquid chromatography with diode array and electrospray ionization mass spectrometric detection (LC-DAD-ESI/MS) was applied to establish the phenolic profiles of 41 green teas and 25 fermented teas. More than 96 phenolic compounds were identified that allowed the teas to be organized into five groups. Epigallocatechin gallate (EGCG) was the major phenolic component of green tea made from mature leaves (group 2), while green tea made from the younger buds and leaves (group 1) contained lower flavonoid concentrations. Partially fermented teas (group 3) contained one-half the EGCG content of the green tea. Fully fermented black teas (group 4) had a trace of EGCG, but contained theaflavins. Highly overfermented black tea (group 5) contained only trace amounts of flavonol glycosides and theaflavins. Over 30 phenolics are new for tea, and this is the first phenolic profile to simultaneously detect C- and O-glycosylated flavonoids, catechins, proanthocyanidins, phenolic acid derivatives, and purine alkaloids.
Journal of Agricultural and Food Chemistry 10/2008; 56(17):8130-40. · 2.82 Impact Factor
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ABSTRACT: A standardized profiling method based on liquid chromatography with diode array and electrospray ionization/mass spectrometric detection (LC-DAD-ESI/MS) was used to analyze the phenolic compounds in the skins of 16 pears (Pyrus spp.). Thirty-four flavonoids and 19 hydroxycinnamates were identified. The main phenolic compounds (based on peak area) in all of the pear skins were arbutin and chlorogenic acid. The remaining phenolics varied widely in area and allowed the pears to be divided into four groups. Group 1, composed of four Asian pears (Asian, Asian brown, Korean, and Korean Shinko), contained only trace quantities of the remaining phenolics. Yali pear (group 2) contained significant amounts of dicaffeoylquinic acids. Fragrant pear (group 3) contained significant quantities of quercetin glycosides and lesser quantities of isorhamnetin glycosides and the glycosides of luteolin, apigenin, and chrysoeriol. The remaining 10 pears (group 4) (Bartlett, Beurre, Bosc, Comice, D'Anjou, Forelle, Peckham, Red, Red D'Anjou, and Seckel) contained significant quantities of isorhamnetin glycosides and their malonates and lesser quantities of quercetin glycosides. Red D'Anjou, D'Anjou, and Seckel pears also contained cyanidin 3-O-glucoside. Thirty-two phenolic compounds are reported in pear skins for the first time.
Journal of Agricultural and Food Chemistry 10/2008; 56(19):9094-101. · 2.82 Impact Factor
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ABSTRACT: Ginkgo biloba leaves and their extracts are one of the most widely used herbal products and/or dietary supplements in the world. A systematic study of the phenolic compounds is necessary to establish quality parameters. A modified LC-DAD-ESI/MS method was used to obtain chromatographic profiles for the flavonoids and terpene lactones of Ginkgo biloba leaves. The method was used to identify 45 glycosylated flavonols and flavones, 3 flavonol aglycones, catechin, 10 biflavones, a dihydroxybenzoic acid, and 4 terpene lactones in an aqueous methanol extract of the leaves. The extracted G. biloba leaf products contained the same flavonoids as the raw leaves except for the lack of biflavones. The detected glycosylated flavonol contents were equal to or more than 0.0008% of the dry plant material. This is the first report of the presence of more than 20 of these flavonoids in G. biloba.
Journal of Agricultural and Food Chemistry 08/2008; 56(15):6671-9. · 2.82 Impact Factor
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ABSTRACT: Profiling methods are needed that separate and detect all the phenolic compounds in a single extract of a food material. These methods must be comprehensive, rapid, and rich in spectral information. Fourteen methods that meet, or have the potential to meet, these criteria have been selected from the recent literature for review. In general, the methods employ a single aqueous methanol extraction, separation on a reversed-phase C column, and detection by UV/vis spectroscopy and mass spectrometry. The variations in extraction, separation, and detection are discussed. An increasingly important aspect of these methods is the archiving of data to permit cross-comparison of samples and standards and retrospective analysis. This review shows that the necessary technology is available to achieve the desired analytical goals.
Analytical and Bioanalytical Chemistry 10/2007; 389(1):47-61. · 3.78 Impact Factor
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ABSTRACT: A screening method using LC-DAD-ESI/MS was applied to the analysis of flavonoids in celery, Chinese celery, and celery seeds (Apium graveolens L. and varieties). Fifteen flavonoid glycosides were detected in the three celery materials. They were identified as luteolin 7-O-apiosylglucoside, luteolin 7-O-glucoside, apigenin 7-O-apiosylglucoside, chrysoeriol 7-O-apiosylglucoside, chrysoeriol 7-O-glucoside, and more than 10 malonyl derivatives of these glycosides. The identification of the malonyl derivatives was confirmed by their conversion into glycosides upon heating and by comparison of some of the malonates with malonates that had previously been identified in red bell pepper and parsley. The concentrations of the glycosides and the malonyl glycosides in the three materials were estimated by comparison to aglycone standards. This is the first report of the presence of these glycosylated flavonoid malonates in celery.
Journal of Agricultural and Food Chemistry 03/2007; 55(4):1321-6. · 2.82 Impact Factor
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ABSTRACT: A screening method was developed for the systematic identification of glycosylated flavonoids and other phenolic compounds in plant food materials based on an initial, standard analytical method. This approach applies the same analytical scheme (aqueous methanol extraction, reverse phase liquid chromatographic separation, and diode array and mass spectrometric detection) to every sample and standard. This standard approach allows the cross-comparison of compounds in samples, standards, and plant materials previously identified in the published literature. Thus, every analysis contributes to a growing library of data for retention times and UV/vis and mass spectra. Without authentic standards, this method provides provisional identification of the phenolic compounds: identification of flavonoid backbones, phenolic acids, saccharides, and acyls but not the positions of the linkages between these subclasses. With standards, this method provides positive identification of the full compound: identification of subclasses and linkages. The utility of the screening method is demonstrated in this study by the identification of 78 phenolic compounds in cranberry, elder flower, Fuji apple peel, navel orange peel, and soybean seed.
Journal of Agricultural and Food Chemistry 03/2007; 55(4):1084-96. · 2.82 Impact Factor
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ABSTRACT: A standardised profiling method based on liquid chromatography with diode array and electrospray ionisation/mass spectrometry (LC-DAD-ESI/MS) was used to identify 46 flavonoids and 17 caffeic acid derivatives in the aqueous methanol extract of Flos chrysanthemum (Chrysanthemum morifolium Ramat) (Compositae), an important Chinese herb. Fifteen caffeoylquinic acids and 15 flavonoids were positively identified and the remaining compounds were provisionally identified. The detected phenolics were present at concentrations greater than 0.001% of the dry plant material. Many of these phenolics have been reported to have human health benefits. Twenty-five compounds, including C-glycosylated flavones and aliphatic acid-containing caffeoylquinic acids, are reported for the first time in chrysanthemum flower, and this comprehensive analysis of the phenolic components of herb Flos chrysanthemum will be helpful for the quality control of this herb and its products, and to understand the usage and function.
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ABSTRACT: Scutellaria lateriflora, commonly known as skullcap, is used as an ingredient in numerous herbal products. However, it has been occasionally adulterated/contaminated with Teucrium canadense and T. chamaedrys, commonly known as germander, which contain hepatotoxic diterpenes. Due to the morphological similarities between the two genera, analytical methodologies to distinguish authentic S. lateriflora from the Teucrium species are needed to ensure public safety. In this study, a direct-injection electrospray ionization/MS method was used to generate spectral fingerprints of extracts from 21 skullcap and germander samples at a rate of 90 s/sample. MS fingerprints were analyzed by principal component analysis. The newly developed method offers a rapid and easy way to differentiate between skullcap and germander samples.
Journal of AOAC International 93(4):1148-54. · 1.20 Impact Factor
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ABSTRACT: Green tea-based dietary supplements (GTDSs) have gained popularity in the U.S. market in recent years. This study evaluated the phytochemical composition difference of GTDS in comparison with green tea leaves using an HPLC/MS fingerprinting technique coupled with chemometric analysis. Five components that are most responsible for class separation among samples were identified as (-) epicatechin gallate, strictinin, trigalloylglucose, quercetin-3-O-glucosyl-rhamnosylglucoside, and kaempferol-3-O-galactosyl-rhamnosylglucoside, according to the accurate mass measurements and MS/MS data. The similarity coefficients between the GTDSs in solid form with green tea were 0.55 to 0.91, while for the GTDSs in liquid form they were 0.12 to 0.89, which suggested that chemical composition variance across the GTDSs was significant. Flavonol aglycone concentrations were higher in GTDSs than in tea leaves, indicating the degradation of flavonol glycosides or the oxidation of catechin during the manufacturing and storage processes. In some GTDS samples, compounds were identified that were on the label. The results demonstrate the urgency of QC for GTDS products.
Journal of AOAC International 94(2):487-97. · 1.20 Impact Factor
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ABSTRACT: LC-DAD-ESI/MS was used to identify 23 flavonoids in the extract of Mexican oregano (Lippia graveolens H.B.K.), a spice and herb, used in the USA and Mexico. The identification of luteolin-7-O-glucoside, apigenin 7-O-glucoside, phloridzin, taxifolin, eriodictyol, scutellarein, luteolin, quercetin, naringenin, pinocembrin and galangin was confirmed by direct comparison with standards. Identification of 6-hydroxyluteolin, two 6-hydroxyluteolin 7-O-glycosides, three pentahydroxyflavanone hexosides, scutellarein 7-O- hexoside, 3-hydroxyphloretin hexoside, and three other flavones, was made by detailed analysis of their UV and mass spectral data. The identification of the flavonoid glycosides was further confirmed through detection of their aglycones following hydrolysis of the samples. The concentration of the identified flavonoids in three samples was also estimated. This is the first report of detection of over 20 flavonoids, including chalcones, in this plant material.
Journal of Food Composition and Analysis.
