Chromatography Diode Array Detection Electrospray Research Articles

Effects of Various Processing Methods on the Metabolic Profile and Antioxidant Activity of Dendrobium catenatum Lindley Leaves.

The metabolite profiles and antioxidant activity of Dendrobium catenatum Lindley leaf, a new functional ingredient for food product development, were evaluated in samples that had been prepared using various methods, including freeze-drying, hot-air drying, rolling before drying, steaming before drying, steaming and rolling before drying, and drying at 100, 80, and 60 °C. The concentrations of polysaccharides and flavonoids, as well as the antioxidant capacity of each sample, were determined. Furthermore, two nucleosides, four amino acids, one monoaromatic compound, and eight flavonoids were identified in dried leaves using high-performance liquid chromatography–diode array detector–electrospray ionization–multistage mass spectrometry (HPLC-DAD-ESI-MSn) and ultraviolet (UV) spectral analyses. The content of polar compounds such as cytidylic acid, arginine, tyrosine, and hydroxybenzoic acid hexose increased dramatically during hot-air-drying and rolling-before-drying treatments, while flavonol C-glycosides remained stable throughout the various treatments and drying temperatures. Rolling before drying at 100 °C was identified as the most suitable process when manufacturing tea products from D. catenatum leaves. This process resulted in a high-antioxidant-activity and visually appealing tea. This report details a potential strategy that should be applied in the manufacturing processes of high-quality products from D. catenatum leaves.

Inhibition of Neutrophil Functions and Antibacterial Effects of Tarragon (Artemisia dracunculus L.) Infusion-Phytochemical Characterization.

The aim of the study was to characterize phytochemicals in an infusion of the aerial parts of tarragon (Artemisia dracunculus L.) using ultra-high-performance liquid chromatography diode array detector electrospray ionisation tandem mass spectrometry UHPLC‐DAD‐ESI‐MS/MS method, as well as an evaluation of its effects on mediators of the inflammation in an in vitro model of human neutrophils, and antimicrobial activity on selected pathogens. Flavonoids and caffeoylquinic acids were the main phenolic components of the extract of tarragon’s aerial parts. The infusion was able to inhibit reactive oxygen species (ROS), interleukin 8 (IL-8), and tumour necrosis factor α (TNF-α) production. The antimicrobial assay was performed with the use of nine strains of bacteria, both Gram-negative and Gram-positive. Three human pathogens, Staphylococcus aureus ATCC6538, Staphylococcus epidermidis ATCC14990, and Staphylococcus aureus MRSA (methicyllin-resistant Staphylococcus aureus) ATCC43300, proved to be the most sensitive to tarragon infusion. Our study demonstrated the antiinflammatory and antimicrobial properties of tarragon (Artemisia dracunculus L.), meaning the common spice may be a prospective source of health-promoting constituents.

Comparison of endometrial prostanoid profiles in three infertile subgroups: the missing part of receptivity?

To study the prostanoid profile of the endometria of patients with recurrent implantation failure (RIF), unexplained infertility (UIF), and recurrent miscarriages (RM), and to compare them with the endometria of healthy fertile controls. Prospective cohort study. University hospital. Fifteen patients with RIF, 18 patients with UIF, 16 patients with RM, and 23 fertile controls were recruited. Endometrial samples were taken during the window of implantation. After tissue homogenization and extraction, analysis with ultra-performance liquid chromatography diode array detector electrospray ionisation tandem mass spectrometry was performed. Concentrations of prostaglandin (PG) D1, PGE1, PGF1α, 6-ketoPGF1α, PGD2, PGE2, PGF2α, 15-deoxy-Δ12,14-PGJ2, PGD3, PGE3, PGF3α, thromboxane B2, 13,14-dihydro-PGE1, 13,14-dihydro-PGF1α, 13,14-dihydro-PGF2α, 13,14-dihydro-15-keto-PGE1, 13,14-dihydro-15-keto-PGE2, and 13,14-dihydro-15-keto-PGF2α were assessed. Comparison of the endometria of patients with UIF and the controls showed no statistically significant differences. When the endometria of patients with RIF were compared with the controls, thromboxane B2 (TXB2) was found significantly higher (843.1 pg/mg vs. 133.5 pg/mg). When the endometria of patients with RM were compared with controls, 13,14-dihydro-15-keto PGF2α and TXB2 were found significantly higher (3907.30 pg/mg vs. 17.80 pg/mg and 858.7 pg/mg vs. 133.5 pg/mg respectively). We identified increased endometrial presence of TXB2 in patients with RM and RIF, and 13,14-dihydro-15-keto PGF2α in patients with RM. Although common ground is observed for RM and RIF, prostanoids, on the other hand, might make their own contribution to endometrial receptivity as important as genes and proteins. Attempts to normalize the prostaglandin profile of the endometrium via enzymatic activity can open new therapeutic options.

Metabolite Profiling of Two Maple-Derived Products Using Dereplication Based on High-Performance Liquid Chromatography-Diode Array Detector-Electrospray Ionization-Time-of-Flight-Mass Spectrometry: Sugar Maple Bark and Bud Hot-Water Extracts.

Recent studies about hot-water extracts from sugar maple (Acer saccharum Marsh.) bark and buds demonstrated that they contain high amounts of phenolic structures that may be used as antioxidant food additives. However, the detailed chemical composition of these maple-derived extracts has yet to be determined. By performing high-performance liquid chromatography-diode array detector-high-resolution mass spectrometry (HPLC-DAD-HRMS)-based dereplication, we were able to spike and classify almost 100 metabolites in each hot-water extract. The sugar maple bark hot-water extract is rich in simple phenolic compounds and phenylpropanoid derivatives, while bud extract contains predominantly flavonoids, benzoic acids, and their complex derivatives (condensed and hydrolyzable tannins). Among those chemical structures, we tentatively identified 69 phenolic compounds potentially reported for the first time in the genus Acer. Considering the growing commercial demand in natural products, the phenolic fingerprints of sugar maple bark and bud hot-water extracts will help in promoting these two maple-derived products as new sources of bioactive compounds in the food, nutraceutical, and cosmetic industries.

UHPLC-DAD-ESI-MS/MS and HPTLC profiling of ash leaf samples from different commercial and natural sources and their in vitro effects on mediators of inflammation.

In European traditional medicine, common ash leaf infusion is recommended by European Medicines Agency to treat minor articular pain and to increase the amount of urine for flushing minor urinary complaints. However, a comprehensive ultra-high-performance liquid chromatography diode array detector electrospray ionisation tandem mass spectrometry (UHPLC-DAD-ESI-MS/MS) analysis of this pharmacopeial plant material has never been performed. Moreover, the number of biological and pharmacological investigations proving the usefulness of this plant material in recommended traditional uses is surprisingly small. Phytochemical profiling of ash leaf samples from different commercial and natural sources and the determination of the in vitro effects on inflammatory mediators in a model of human neutrophils. Ash leaf samples were characterised by total hydroxycinnamic acid content and by high-performance thin layer chromatography (HPTLC), UHPLC-DAD-ESI-MS/MS methods. The effects of leaf infusions on reactive oxygen species (ROS), tumor necrosis factor (TNF-α), interleukin 8 (IL-8), interleukin 1β (IL-1β), and monocyte chemoattractant protein 1 (MCP-1) production by neutrophils were measured using luminol-dependent chemiluminescence and enzyme-linked immunosorbent assay (ELISA). In ash leaf samples 64 compounds were identified or partly identified together with four unknown compounds. The major compounds detected belong to different structural groups, including phenolic acid derivatives, phenylethanoids, flavonoids, iridoids, secoiridoids and lignans. The major compounds detected in ash samples were chlorogenic acid, quercetin-3-O-rutinoside, verbascoside, oleuropein and ligstroside. However, one sample contained coumarin derivatives. This finding suggested adulteration with other Fraxinus species and/or plant parts. All infusions were able to inhibit ROS, cytokine and chemokine production. The performed phytochemical and biological analyses contribute to the knowledge about this pharmacopeial plant material and supports its traditional use to treat minor inflammatory complaints.

Phenolic compounds profile and biochemical properties of honeys in relationship to the honey floral sources

Honey has been considered to have therapeutic properties since ancient times and among the factors responsible for such activity are phenolic compounds including phenolic acids and flavonoids from different natural sources. This study investigated the phenolic compounds profile and bioactive properties of different honey types from Romanian flora in order to develop reliable tools for honey floral origin, thus contributing to the honey traceability in the European Union context. Thirty-three honey samples were examined, including unifloral (acacia and rape), polyfloral, honeydew honeys and mixture honeys. Phenolic acids and flavonoids were isolated from the water soluble honey matrix using a solid-phase extraction (SPE) method and analysed by ultra-high-performance liquid chromatography diode array detector electrospray ionisation mass spectrometry (UHPLC-DAD-ESI/MS). Honey bioactive properties were measured in honey dissolved in 80% ethanol using UV-visible spectrophotometric methods. Multivariate statistical tools (principal component analysis and hierarchical clustering analysis) were used for honey classification. The results of this study confirm that honey samples had similar, but quantitatively different, phenolic acids and flavonoids profiles and bioactive properties, related with honey floral source. Coloured honeys, such as honeydew honey, show high phenolic composition and bioactive properties and implicitly a high therapeutic potential compared with the other floral honeys. Distinctive clusters obtained by principal component analysis enabled us to consider that honeydew and polyfloral honeys could be distinguished from acacia and rape honey with the analytical methods developed. Based on this study, the methods might be promising tools for honey traceability, which needs to be explored on a larger set of samples with different regional floral origins in future studies.

Identification Markers of Adulteration in Korean Red Ginseng (Panax Ginseng) Products Using High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography–Mass Spectrometry (LC-MS)

ABSTRACTThe commercial products of Panax ginseng have increasing market demand and high prices due to the pharmacological activities. To obtain high profits, P. ginseng may be adulterated with lower priced morphologically similar species such as Platycodon grandiflorum, Codonopsis lanceolata, and Pueraria lobata. This study was designed to validate accurate methods for the analysis of adulteration in P. ginseng products. High-performance liquid chromatography (HPLC) and ultraperformance liquid chromatography–diode array detector–electrospray ionization–ion trap–time of flight–mass spectrometry (UPLC–DAD–ESI-IT-TOF-MS) were validated to analyze the raw plant materials, self-prepared formulations, and commercial products of P. ginseng, C. lanceolata, P. grandiflorum, and P. lobata. The developed analytical methods were confirmed by quality assurance parameters such as linearity, sensitivity, precision, and accuracy. Lobetyolin and ononin were identified as marker compounds by HPLC and confirmed by accurate mass measurement with ESI-IT-TOF-MS. HPLC analysis of self-prepared formulations indicated that by increasing the ratio of C. lanceolata, P. grandiflorum, and P. lobata in P. ginseng extracts, the peak area is increased at the same retention time. The limits of detection and quantification for lobetyolin and ononin were 0.098 and 0.171, and 0.108 and 0.726 mg/kg, respectively. Furthermore, the intraday precision (<1.0%) measurements confirmed that the developed analytical methods fulfill the required criteria for characterization of these products. The results demonstrated that the developed liquid chromatographic and mass spectrometric methods accurately characterized adulteration in P. ginseng commercial products.

Rapid Screening of Potential Phosphodiesterase Inhibitors from the Roots of Ilex pubescens Hook. et Arn. Using a Combination of Ultrafiltration and LC-MS.

The cyclic nucleotide phosphodiesterase (PDE) plays an important role in regulating the levels of second messenger molecules cAMP and cGMP. Various PDE inhibitors have been successfully developed into drugs for targeted diseases. In addition, PDE inhibitors can also be found in different foods and natural medicines. In this study, ultrafiltration liquid chromatography–diode-array detector–electrospray ionization–ion-trap–time-of-flight–mass spectrometry (ultrafiltration LC–DAD–ESI–IT–TOF–MS) was applied to screen PDE inhibitors from the roots of Ilex pubescens Hook. et Arn. As a result, 11 major compounds were identified in I. pubescens roots, with nine compounds as potential PDE inhibitors, among which five were further confirmed to be active against PDEI and PDE5A dose-dependently in vitro, with ilexsaponin A1 and ilexsaponin B2 being the strongest. HPLC quantification of these bioactive compounds suggested that they are major components in the plant. The results demonstrate that ultrafiltration LC–DAD–ESI–IT–TOF–MS is an efficient method for rapid screening of PDE inhibitors from natural medicines.

Characterization of flavonoid glycosides from rapeseed bee pollen using a combination of chromatography, spectrometry and nuclear magnetic resonance with a step-wise separation strategy

To identify the structures of flavonoid glycosides in bee pollen collected from rapeseed plants (Brassica napus L.), we utilised an approach that combined liquid chromatography–diode array detector–electrospray ionization–mass spectrometry (LC–DAD–ESI–MS) and nuclear magnetic resonance (NMR) technology with a step-wise separation strategy. We identified four constituents of high purity in rape bee pollen samples: (1) quercetin-3-O-β-D-glucosyl-(2→l)-β-glucoside, (2) kaempferol-3, 4′-di-O-β-D-glucoside, (3) 5, 7, 4′-trihydroxy-3′-methoxyflavone-3-O-β-D-sophoroside and (4) kaempferol-3-O-β-D-glucosyl-(2→l)-β-D-glucoside. This study will also provide useful reference standards for qualification and quantification of four flavonoid glycosides in natural products.

Determination of phenolic compounds and antioxidant activity of a Mediterranean plant: The case of Satureja montana subsp. kitaibelii

Satureja montana subsp. kitaibelii extract was analyzed by HPLC–DAD–ESI–TOF–MS (high performance liquid chromatography–diode array detector–electrospray ionization–time of flight–mass spectroscopy). Forty five compounds were identified, 42 of which were identified for the first time in this plant. Quantification of the identified phenolic compounds by UV–vis (ultraviolet–visible) detection was done and chlorogenic acid was the most concentrated compound. Total phenolic content (TPC) by Folin–Ciocalteu method and antioxidant activity by DPPH and ABTS methods were also measured. TPC quantified by HPLC–DAD were 1958.44 mg/100 g dry sample. This is in agreement with TPC measured by Folin–Ciocalteu method. Antioxidant activity determined by the DPPH method expressed as EC50 was 116.36 ± 12.83 µg/mL and by the ABTS method was 106.59 ± 1.41 µmol trolox equivalents/g dry sample. These results reveal that Satureja montana subsp. kitaibelii could be a good functional food ingredient because its high content of natural antioxidants as demonstrated by quantification with HPLC–DAD.

Simultaneous qualitative and quantitative analysis of phenolic acids and flavonoids for the quality control of Apocynum venetum L. leaves by HPLC–DAD–ESI–IT–TOF–MS and HPLC–DAD

A reliable method based on high performance liquid chromatography–diode array detector–electrospray ionization–ion trap–time of flight–mass spectrometry (HPLC–DAD–ESI–IT–TOF–MS) was developed for the identification of phenolic acids and flavonoids in Apocynum venetum L. leaves and its adulterant, Pocynum hendersonii (Hook. f.) Woodson leaves. A total of 21 compounds were identified or tentatively identified, including 4 phenolic acids and 17 flavonoids. 3-O-caffeoylquinic acid (3-CQA) and caffeic acid were detected for the first time in A. venetum leaves; 4-O-caffeoylquinic acid (4-CQA), 3-CQA, caffeic acid, quercetin-3-O-(6″-O-malonyl)-galactoside, quercetin-3-O-(6″-O-malonyl)-glucoside, kaempferol-3-O-(6″-O-malonyl)-glucoside, kaempferol-3-O-(6″-O-acetyl)-glucoside, and kaempferol-3-O-dihexoside were detected for the first time in P. hendersonii leaves. Cluster analysis was employed to analyze 24 batches of A. venetum leaves and 5 batches of P. hendersonii leaves collected from various regions in China. The analysis, which was based on the 21 compounds, indicated that profiles of these compounds were distinct between the two species, and among A. venetum leaf samples from different origins. 18 of these 21 compounds were selected as the markers and simultaneously analyzed by HPLC–DAD for the first time. The quantitative analytical method was validated and subsequently applied to the comprehensive quality evaluation of 24 batches of A. venetum leaves.

Pressurised liquid extraction combining LC–DAD–ESI/MS analysis as an alternative method to extract three major flavones in Citrus reticulata ‘Chachi’ (Guangchenpi)

Pressurised liquid extraction (PLE) of three major flavones (hesperidin, nobiletin, and tangeretin) from the peels of Citrus reticulata ‘Chachi’ (Guangchenpi) was investigated. These flavones were quantified and analysed by liquid chromatography–diode array detector–electrospray ionisation mass spectrometry (LC–DAD–ESI/MS). The PLE procedure was optimised, validated and compared with other conventional extraction techniques. PLE gained the best result due to the highest extraction efficiency within the shortest extraction time. The optimal conditions of PLE were employing 70% methanol as extraction solvent at a temperature of 160°C and extraction pressure of 1500psi, using one extraction cycle with a static extraction time of 20min. MS coupling with an ESI interface in the positive ion mode was used as the detection technique. This is the first report on combining PLE with LC–DAD–ESI/MS for the extraction and quantification of flavones in Citrus reticulata ‘Chachi’.

The flavonoid composition of flavedo and juice from the pummelo cultivar (Citrus grandis (L.) Osbeck) and the grapefruit cultivar (Citrus paradisi) from China

The flavonoid composition of flavedos and juices from four Chinese pummelo cultivars (Citrus grandis ‘Shatianyu’, C. grandis ‘Guanximiyu’, C. grandis ‘Yuhuanyu’, and C. grandis ‘Cuixiangtianyu’) and one grapefruit cultivar (Citrus paradisi ‘Changshanhuyu’), was investigated using high-performance liquid chromatography diode array detection electrospray ionisation mass spectrometry (HPLC-DAD-ESI MS/MS). Twenty-eight flavonoids were identified. Naringin was the predominant flavanone in these pummelo varieties, whereas naringin and neohesperidin were the principal flavanones found in C. paradisi ‘Changshanhuyu’. The four pummelo cultivars had higher levels of flavones when compared with the grapefruit. Based on the flavonoid profiles in flavedos and juices, four pummelo cultivars and one grapefruit cultivar were well separated.

Characterization of flavone glycosides and aglycones in Cephalotaxus sinensis by HPLC-DAD-MS

High performance liquid chromatography diode array detector electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS) was utilized to separate and identify flavone glycosides and aglycones in Cephalotaxus sinensis, a natural plant with an anti-hyperglycemic effect. The HPLC-DAD-ESI-MS system could provide a great amount of information on the structure of flavone aglycones and glycosides in C. sinensis without time-consuming pre-separation or purification procedures. A total of seven flavone glycosides and two flavone aglycones were unambiguously identified based on their retention times, ultraviolet spectra, molecular weights and MS/MS spectra. It's interesting that five 5-O-flavone glycosides were found in C. sinensis since 5-O-flavone glycosides are rare and difficult to form in the natural plant. Among them, quercitrin and apigenin-5-O-β-D-glucopyranoside were isolated from this genus for the first time. A novel flavone glycoside, chryoseriol-5-O-[α-L-rhamnopyranosyl-(1→4)-β-D-6-O-acetylglucopyranoside], was isolated for the first time and identified by the ultraviolet spectrum, infrared spectrum, mass spectrum and nuclear magnetic resonance spectrum. In addition, the proposed fragment pathway of the novel flavone glycoside was concluded in the negative ionization mode by HPLC-ESI-MS/MS.

Simultaneous analysis of alkaloids from Zanthoxylum nitidum by high performance liquid chromatography–diode array detector–electrospray tandem mass spectrometry

The chemical profiles of nine alkaloids in Zanthoxylum nitidum, including berberubine, coptisine, sanguinarine, nitidine, chelerythrine, liriodenine, 6,7,8-trimethoxy-2,3-methylendioxybenzophenantridine, oxyavicine and dihydrochelerythrine, were identified by using high performance liquid chromatography–diode array detector–electrospray tandem mass spectrometry (HPLC–DAD–ESI–MS), and a novel and sensitive HPLC–UV method had been developed to simultaneously determine these alkaloids in 70% methanol extract of Zanthoxylum nitidum. The chromatographic separation was performed on an Agilent C 18 analytical column (5 μm, 4.6 mm i.d., 250 mm length) with a gradient solvent system of acetonitrile–0.1% formic buffer (adjusted to pH 4.5 with triethylamine). The methodological validation was carried out and the linearities ( r 2 > 0.9997) and recoveries (ranged from 98.3% to 101.1%) were acceptable. The limits of detection (LOD) of these alkaloids were ranged from 0.6 ng to 1.5 ng. The results indicated that the contents of alkaloids in Zanthoxylum nitidum varied significantly from habitat to habitat with contents ranged from 0.03 mg/g to 3.34 mg/g. The proposed method is simple, effective and suitable for the quality control of this traditional Chinese medicine (TCM). It suggests that it is necessary to control its quality so as to insure efficacy and safety of TCM.

A comparison of deconvolution methods as applied to high performance liquid chromatography–diode array detector–electrospray mass spectrometry of 2- and 3-hydroxypyridine at varying pH in the presence of severely tailing peak shapes

Triply coupled high performance liquid chromatography–diode array detection–electrospray mass spectrometry of a mixture of 2- and 3-hydroxypyridine were recorded at pH 5.0, 5.1 and 5.2. At each pH the resolution changes with almost complete overlap at pH 5.1. A variety of chemometric methods including raw, normalised and standardised principal component analysis (PCA), derivatives, evolving factor analysis (EFA), fixed size window EFA, spectral similarity indices (SSI) and peak ratios are applied to the data for both detectors and all pH. Methods of deconvolution are also applied to both the diode array and mass spectral data.