ABSTRACT
Five unusual seco-nortriterpenoids, 3ß-hydroxy-20,21-seco-30-nortaraxastan-20,21-dioic acid (1), 3ß-hydroxy-20,21-seco-30-nortaraxastan-20-oic-21-oate (2), 3ß-hydroxy-20-oxo-21,22-seco-30-nortaraxastan-22-oic acid (3), 3ß-hydroxy-19-oxo-20,21-seco-29,30-nortaraxastan-21-oic acid (4) and 3ß-hydroxy-19-oxo-20,21-seco-19-norlupan-21-oic acid (5) were isolated and elucidated from the anti-inflammatory activity fraction of the ethanol extract of Cirsium setosum. The structures of these compounds were established through spectroscopic methods. Preliminary biological assays showed that compounds 1-5 had significant inhibitory effect on NO production on lipopolysaccharide-stimulated RAW 264.7 cells, and compound 1 showed the strongest anti-inflammatory activity. This type of ring-opening compound is the first seco-triterpenoid structure discovered from the genus of Cirsium.
Subject(s)
Anti-Inflammatory Agents , Cirsium , Nitric Oxide , Phytochemicals , Triterpenes , RAW 264.7 Cells , Animals , Mice , Cirsium/chemistry , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/isolation & purification , Molecular Structure , Triterpenes/pharmacology , Triterpenes/isolation & purification , Triterpenes/chemistry , Nitric Oxide/metabolism , Phytochemicals/pharmacology , Phytochemicals/isolation & purification , Plant Extracts/pharmacology , Plant Extracts/chemistryABSTRACT
Three new ursane-type triterpenoids, 3-oxours-12-en-20, 28-olide (1), 3ß-hydroxyurs-12-en-20, 28-olide (2) and 3ß-hydroxyurs-11, 13(18)-dien-20, 28-olide (3), were isolated from a potent anti-inflammatory and antibacterial fraction of the ethanolic extract of Rosmarinus officinalis. Their structures were elucidated by a combination of extensive 1D- and 2D-NMR experiments, MS data and comparisons with literature reports. Compounds 1-3 exhibited significantly inhibitory effects on nitric oxide production in lipopolysaccharide-activated mouse RAW264.7 macrophages, but no antibacterial activity was found at a concentration of 128 µg·mL-1.
Subject(s)
Drugs, Chinese Herbal , Rosmarinus , Triterpenes , Animals , Drugs, Chinese Herbal/chemistry , Mice , Molecular Structure , Triterpenes/chemistryABSTRACT
Two new dimeric and trimeric sesquiterpene lactones (1-2), and nine known sesquiterpene lactones (3-11) were isolated from the EtOAc phase of the ethanolic extract of Ainsliaea yunnanensis. Their structures were identified by NMR, IR and HR-ESIMS spectroscopic methods, and compound 1 was confirmed by single crystal X-ray diffraction experiment. All the compounds were tested for their cytotoxic, anti-microbial and anti-inflammatory activities. Compounds 1, 2, 3, 5, 7, 9 and 11 showed very significant selective cytotoxic activities on MDA-MB-468, PANC-1, HEPG2 or A549 cells. Compounds 6 and 11 showed very significant inhibiting effect on Epicoccum sp. (CPCC 400307), Fusarium solani (CPCC 800013) or Bacillus subtilis. Meanwhile, compounds 6 and 7 can inhibit the NLRP3 inflammasome's activation at the concentration of 10 µM.
Subject(s)
Asteraceae , Sesquiterpenes , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Asteraceae/chemistry , Inflammasomes , Lactones/chemistry , Molecular Structure , NLR Family, Pyrin Domain-Containing 3 Protein , Phytochemicals , Plant Extracts/chemistry , Sesquiterpenes/chemistryABSTRACT
Five norursane-type triterpenoids, including three novel of 3ß-28-norursa-12,17,19,21-tetraene-3-ol (1), 3ß-28-norursa-12,20(30)-dien-3-ol (2) and 3ß-28-norursa-12,16,20(30)-triene-3-ol (3), as well as two known 3ß-28-norursa-17,19,21-trien-3-ol (4) and 3ß-28-norursa-12-ene-3-ol (5) were isolated from the ethyl acetate dissolved fraction of the ethanol extract from Rosmarinus officinalis. Their structures were elucidated by HR-ESI-MS, IR, 1D- and 2D-NMR spectroscopic methods. Compounds 1-5 exhibited significant inhibitory effect on NO production in LPS-activated RAW264.7 cells, and compounds 2, 3 and 5 shown better anti-inflammatory activity.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Rosmarinus/chemistry , Triterpenes/pharmacology , Animals , Anti-Inflammatory Agents/isolation & purification , China , Mice , Molecular Structure , Phytochemicals/isolation & purification , Phytochemicals/pharmacology , Plant Components, Aerial/chemistry , RAW 264.7 Cells , Triterpenes/isolation & purificationABSTRACT
Searching for PD-1/PD-L1 inhibitor from medicinal plants has become a potential method to discover small molecular cancer immunotherapy drugs. Using PD-1/PD-L1 inhibitory activity assay in vitro, a bioactive fraction was obtained from the ethanol extract of Gymnadenia conopsea. A sensitive UPLC-HRMS/MS method was established for the rapid screening and identification of compositions from bioactive fraction. Based on the characteristic fragmentation patterns of standards analysis and extracted ion chromatogram (EIC) method, 46 compounds were rapidly screened and identified (including 35 succinic acid ester glycosides and 11 other compounds), among which 17 compounds were tentatively identified as new compounds.
Subject(s)
Ethanol , Programmed Cell Death 1 Receptor , B7-H1 Antigen , Chromatography, High Pressure Liquid , Molecular StructureABSTRACT
Gymnadenia conopsea R. Br. is a traditional Tibetan medicinal plant that grows at altitudes above 3000 m, which is used to treat neurasthenia, asthma, coughs, and chronic hepatitis. However, a comprehensive configuration of the chemical profile of this plant has not been reported because of the complexity of its chemical constituents. In this study, a rapid and precise method based on ultra-high performance liquid chromatography (UPLC) combined with an Orbitrap mass spectrometer (UPLC-Orbitrap-MS/MS) was established in both positive- and negative-ion modes to rapidly identify various chemical components in the tubers of G. conopsea for the first time. Finally, a total of 91 compounds, including 17 succinic acid ester glycosides, 9 stilbenes, 6 phenanthrenes, 19 alkaloids, 11 terpenoids and steroids, 20 phenolic acid derivatives, and 9 others, were identified in the tubers of G. conopsea based on the accurate mass within 3 ppm error. Furthermore, many alkaloids, phenolic acid derivates, and terpenes were reported from G. conopsea for the first time. This rapid method provides an important scientific basis for further study on the cultivation, clinical application, and functional food of G. conopsea.
Subject(s)
Orchidaceae/chemistry , Plant Tubers/chemistry , Tandem Mass Spectrometry/methods , Chromatography, High Pressure Liquid , Esters/chemistry , Glycosides/chemistry , Phytochemicals/analysis , Plant Extracts/chemistry , Succinic Acid/chemistryABSTRACT
Guided by TNF-α secretion inhibitory activity assay, four taraxastane-type triterpenoids, including two new ones, 22-oxo-20-taraxasten-3ß, 30-diol (1) and 22α-hydroxy-20-taraxasten-30ß, 30-triol (2), have been obtained from an active fraction of the petroleum ether-soluble extract of the the medicinal and edible plant Cirsium setosum. Their structures were elucidated by spectroscopic data and CD data analysis. In the TNF-α secretion inhibitory activity assay, compounds 1 and 2 were active with the IC50 of 2.6 and 3.8 µmol·L-1, respectively. In addition, compounds 1 and 2 showed moderately selective cytotoxicity against the human ovarian cancer (A2780) and colon cancer (HCT-8) cell lines.
Subject(s)
Cirsium/chemistry , Plants, Edible/chemistry , Plants, Medicinal/chemistry , Triterpenes/chemistry , Animals , Cell Line, Tumor , Cell Survival/drug effects , Ether/chemistry , Humans , Macrophages/drug effects , Macrophages/metabolism , Mice , Molecular Structure , Plant Extracts/chemistry , Plant Extracts/pharmacology , Triterpenes/isolation & purification , Triterpenes/pharmacology , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Three previously undescribed iridoids, cornusfurals Aâ»C, were isolated from the ethanolic extracts of fruits of Cornus officinalis. Their structures were elucidated by spectroscopic methods, including one-dimensional and two-dimensional nuclear magnetic resonance, ultraviolet spectroscopy, infrared spectroscopy, and mass spectrometry. The neuroprotective activity was evaluated by measuring corticosterone-induced damage in PC12 cells. The results showed that cornusfural B decreased corticosterone-induced PC12 cell damage compared with that in model cells.
Subject(s)
Cornus/chemistry , Corticosterone/adverse effects , Iridoids/isolation & purification , Iridoids/pharmacology , Neurons/cytology , Animals , Ethanol/chemistry , Ethanol/isolation & purification , Fruit/chemistry , Iridoids/chemistry , Magnetic Resonance Spectroscopy , Mass Spectrometry , Molecular Structure , Neurons/drug effects , Neuroprotection , PC12 Cells , Plant Extracts/chemistry , Rats , Spectrophotometry, InfraredABSTRACT
Four new iridoid glycosides named cornusphenosides A-D (1-4) were isolated from an ethanol extract of the fruits of Cornus officinalis (shan zhu yu). The structures of these compounds were elucidated on the basis of spectroscopic data (UV, IR, HRESIMS, and 1D and 2D NMR) and chemical evidence. The neuroprotective effects of compounds 1-4 were also assessed in vitro.
Subject(s)
Cornus/chemistry , Iridoid Glycosides/isolation & purification , Fruit/chemistry , Humans , Iridoid Glycosides/chemistry , Iridoid Glycosides/pharmacology , Magnetic Resonance Spectroscopy , Neuroprotective Agents/pharmacology , Plant Extracts/analysisABSTRACT
Four new taraxastane-type triterpenoids acids 3ß,22α-dihydroxy-20-taraxasten-30-oic acid (1), 3ß-hydroxy-22-oxo-20-taraxasten-30-oic acid (2), 3-oxo-22α-hydroxy-20- taraxasten-30-oic acid (3), and 3ß,19ß-dihydroxy-20-taraxasten-30-oic acid (4) were isolated and characterized from Cirsium setosum (Willd.) MB. Their structures were determined by the combination of 1D and 2D NMR experiments ((1)H-(1)HCOSY, HSQC, HMBC and ROESY) and mass spectrometry. Compound 2 exhibited potent selective cytotoxicity against human ovarian cancer cell line A2780 with an IC50 value of 3.9 µM.
Subject(s)
Cirsium/chemistry , Triterpenes/isolation & purification , Drugs, Chinese Herbal/chemistry , Humans , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Triterpenes/chemistry , Triterpenes/pharmacologyABSTRACT
AIM: To investigate the protective effect of glutamine (Gln) on intestinal injury and the bacterial community in rats exposed to hypobaric hypoxia environment. METHODS: Sprague-Dawley rats were divided into control, hypobaric hypoxia (HH), and hypobaric hypoxia + Gln (5.0 g/kg BW·d) (HG) groups. On the first 3 d, all rats were placed in a normal environment. After the third day, the HH and HG groups were transferred into a hypobaric chamber at a simulated elevation of 7000 m for 5 d. The rats in the HG group were given Gln by gavage daily for 8 d. The rats in the control and HH groups were treated with the same volume of saline. The intestinal morphology, serum levels of malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-gamma (IFN-γ) and diamino oxidase (DAO) were examined. We also evaluated the expression levels of occludin, toll-like receptor 4 (TLR4), nuclear factor-κB p65 (NF-κB p65) and myeloid differentiation factor 88 (MyD88), and examined the bacterial community in caecal contents. RESULTS: Hypobaric hypoxia induced the enlargement of the heart, liver, lung and kidney, and caused spleen atrophy. Intestinal villi damage was also observed in the HH group. Supplementation with Gln significantly alleviated hypobaric-induced damage to main organs including the intestine, increased serum SOD (1.14 ± 0.03 vs 0.88 ± 0.04, P < 0.05) and MDA (8.35 ± 1.60, P < 0.01) levels and decreased serum IL-6 (1172.13±30.49 vs 1407.05 ± 34.36, P < 0.05), TNF-α (77.46 ± 0.78 vs 123.70 ± 3.03, P < 0.001), IFN-γ (1355.42 ± 72.80 vs 1830.16 ± 42.07, P < 0.01) and DAO (629.30 ± 9.15 vs 524.10 ± 13.34, P < 0.001) levels. Moreover, Gln significantly increased occludin (0.72 ± 0.05 vs 0.09 ± 0.01, P < 0.001), TLR4 (0.15 ± 0.05 vs 0.30 ±0.09, P < 0.05), MyD88 (0.32 ± 0.08 vs 0.71 ± 0.06, P < 0.01), and NF-κB p65 (0.16 ± 0.04 vs 0.44 ± 0.03, P < 0.01) expression levels and improved the intestinal bacterial community. CONCLUSION: Gln treatment protects from intestinal injury and regulates the gut flora imbalance in hypoxia environment. These effects may be related to the TLR4/MyD88/NF-κB signaling pathway.
Subject(s)
Bacteria/drug effects , Glutamine/pharmacology , Hypoxia/drug therapy , Intestines/drug effects , Animals , Bacteria/classification , Bacteria/growth & development , Cytokines/blood , Cytoprotection , Disease Models, Animal , Hypoxia/immunology , Hypoxia/metabolism , Hypoxia/microbiology , Hypoxia/pathology , Inflammation Mediators/blood , Intestinal Mucosa/metabolism , Intestines/immunology , Intestines/microbiology , Intestines/pathology , Male , Malondialdehyde/blood , Myeloid Differentiation Factor 88/metabolism , Rats, Sprague-Dawley , Signal Transduction/drug effects , Superoxide Dismutase/blood , Time Factors , Toll-Like Receptor 4/metabolism , Transcription Factor RelA/metabolismABSTRACT
The compounds of Ainsliaea yunnanensis were isolated and purified by various kinds of column chromatography methods and their structures were determined by spectroscopic data analysis. Twelve compounds were obtained from the petroleum ether of ethanolic extract of A. yunnanensis and elucidated as bauerenyl acetate (1), bauerenol (2), alpha-amyrin (3), psi-taraxasterol (4), beta-amyrin (5), echinocystic acid (6), multiflorenol (7), 3beta-hydroxy-olean-18-ene germanicol (8), 3beta-hexadecanoyl-12-oleanen-11-one (9), fernenol (10), fern-7-en-3beta-ol (11), and lupeol (12). All compounds were isolated from this genus for the first time except compound 1, 3, 5 and 10, and they were all isolated from this plant for the first time.
Subject(s)
Asteraceae/chemistry , Drugs, Chinese Herbal/chemistry , Triterpenes/chemistry , Drugs, Chinese Herbal/isolation & purification , Molecular Structure , Spectrometry, Mass, Electrospray Ionization , Triterpenes/isolation & purificationABSTRACT
A new dihydroflavonol glycoside dimer 6,6-bisastilbin (1) and a new nitrile-containing metabolite (Z)-5α,6ß-dihydroxy-4ß-methoxy-2-cyclohexene-Δ(1,α)-acetonitrile (2), together with three known analogs, bauhinin, bauhinilide, and dehydrodicatechin A, have been isolated from an ethanol extract of Bauhinia aurea. Their structures were determined by spectroscopic and chemical methods.
Subject(s)
Bauhinia/chemistry , Drugs, Chinese Herbal/isolation & purification , Flavonols/chemistry , Flavonols/isolation & purification , Glycosides/isolation & purification , Drugs, Chinese Herbal/chemistry , Glycosides/chemistry , Nuclear Magnetic Resonance, Biomolecular , Plant Stems/chemistryABSTRACT
Two new triterpenoids taraxer-14-ene-1alpha,3beta-diol (1) and 3beta-hydroxytaraxer-14-ene-1-one (2), together with the known triterpenes taraxerol (3), betulin (4), betulinic acid (5), sumaresinolic acid (6), and 5-hydroxy-2-methoxy-1,4-naphthoquinone (7), 5,7-dihydroxy-6,8-dimethylchromone (8), alpha-monpalmitin (9), palmitic acid (10), 6beta-hydroxystigmast-4-en-3-one (11), beta-sitostero1 (12), have been isolated from the petroleum ether fraction of the ethanolic extract of Pterospermum heterophyllum. Their structures were established by spectroscopic methods including IR, MS, 1D, and 2D NMR experiments. Compounds 1-8 were evaluated against several human cancer cell lines. Compound 1 showed in vitro selective cytotoxicity against human lung cancer cell lines (A549) with an IC(50) value of 1.22 microM. Compound 7 showed significant cytotoxicity against the A549, HCT-8, Bel7402, BGC-823, and A2780 cancer cell lines with IC(50) values of 0.21, 0.55, 0.40, 0.59, and 0.34 microM, respectively. However, the other compounds were inactive (IC(50)>10 microM).
Subject(s)
Antineoplastic Agents, Phytogenic/isolation & purification , Drugs, Chinese Herbal/isolation & purification , Malvaceae/chemistry , Triterpenes/isolation & purification , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Drug Screening Assays, Antitumor , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/pharmacology , Female , Humans , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Oleanolic Acid/analogs & derivatives , Oleanolic Acid/chemistry , Oleanolic Acid/isolation & purification , Palmitic Acid/chemistry , Pentacyclic Triterpenes , Plant Roots/chemistry , Sitosterols/chemistry , Sitosterols/isolation & purification , Stereoisomerism , Terpenes , Triterpenes/chemistry , Triterpenes/pharmacology , Betulinic AcidABSTRACT
The research advances based on the related references were summarized in the last thirty years. Bauhinia contained many kinds of chemical constituents, primarily including flavanoids, steroids, terpenoid and so on, some of them were firstly obtained from the nature. Many plants of the Bauhinia are used in traditional medicine for their interesting biological activities such as antidiabetic, antiinflammatory, antimicrobial, analgesic, astringent and diuretic effects. This paper gives an overview of phytochemical and pharmacological research in Bauhinia, and it has been classified accordding to the chemical structure characteristics. To provide more material to draw on for further development and utilization resources of Bauhinia.
Subject(s)
Bauhinia/chemistry , Drugs, Chinese Herbal/pharmacology , Drugs, Chinese Herbal/therapeutic use , PhytotherapyABSTRACT
OBJECTIVE: To study the chemical constituents from the active fractions against HIV in vitro, a crude ethanolic extract of Illicium simonsii. METHOD: The compounds were isolated with column chromatography methods. MS and NMR spectroscopic methods were used to determine the structures of the compounds. RESULT: Seven compounds were isolated from the active fractions against HIV in vitro of the 90% ethanol extract and their structures were elucidated as (+)-catechin (1), (-)-epicatechin (2), (+)-catechin 3-O-alpha-L-rhamnopyranoside (3), kaempferol 3-O-alpha-L-rhamnopyranoside (4), quercetin 3-O-alpha-L-rhamnopyranoside (5), erigeside C (6) and daucosterol (7). CONCLUSION: Seven compounds were isolated from this plant for the first time, but none of them exhibited active against HIV in vitro. Compounds 3 and 6 were isolated from this genus for the first time.
Subject(s)
Drugs, Chinese Herbal/chemistry , Illicium/chemistry , Catechin/chemistry , Ethanol/chemistry , Glycosides/chemistry , Magnetic Resonance Spectroscopy , Mass Spectrometry , Rhamnose/analogs & derivatives , Rhamnose/chemistry , Sitosterols/chemistryABSTRACT
OBJECTIVE: To investigate the chemical constituents of the brach of Macaranga adenantha, and evaluate their TNF-alpha inhibitory activity. METHOD: The chemical conshifuents were isolated and purified by chromatographic methods. Structures of the compounds were identified by spectroscopic methods. The TNF-alpha secretion inhibitory activity of the mouse peritoneal macrophages was evaluated by MTT methods. RESULT: Ten compounds were isolated and their structures were identified as: cleomiscosin A (1), cleomiscosin B (2), ellagic acid 4-O-alpha-D-rhamnopyranside (3), ellagic acid 4-O-beta-D-xylopyranoside (4), vanillic acid (5), (24R) -stigmast-4-en-3-one (6), (24R) -stigmast-3, 6-dione (7), (24R) -6beta-hydroxy-stigmast-4-en-3-one (8), daucosterol (9), beta-sitosteryl glucoside-6'-O-heptadecoicate (10). At a concentration of 10 micromol x L(-1), compounds 1, 3 and 4 showed inhibitory activity to TNF-alpha secretion of the mouse peritoneal macrophages with the inhibitory rates of 57.0%, 64.4%, and 57. 4%, respectively. CONCLUSION: All compounds were isolated from genus Macaranga for the first time. Compounds 1, 3, and 4 were active against TNF-alpha secretion of the mouse peritoneal macrophages.
Subject(s)
Coumarins/isolation & purification , Ellagic Acid/analogs & derivatives , Euphorbiaceae/chemistry , Tumor Necrosis Factor-alpha/metabolism , Animals , Cell Survival/drug effects , Coumarins/chemistry , Coumarins/pharmacology , Ellagic Acid/chemistry , Ellagic Acid/isolation & purification , Ellagic Acid/pharmacology , Macrophages, Peritoneal/cytology , Macrophages, Peritoneal/drug effects , Macrophages, Peritoneal/metabolism , Mice , Plant Stems/chemistry , Plants, Medicinal/chemistryABSTRACT
OBJECTIVE: To study the chemical constituents of Bauhinia aurea. METHOD: The compounds were isolated by column chromatography over silica gel, reversed-phase RP-18, and Sephadex LH -20. MS and NMR spectroscopic methods were used to determine structures of purified compounds. RESULT: Eight compounds were isolated from the ethyl acetate soluble fraction of the ethanolic extract and their structures were elucidated as isoengeletin (1), astilbin (2), neoastilbin (3), isoastilbin (4), neoisoastilbin (5), (+)-catechin (6), (-)-epicatechin (7) and (-)-epicatechin 3-O-gallate (8). CONCLUSION: Five compounds were isolated from this genus for the first time except for 2, 6 and 8.
Subject(s)
Bauhinia/chemistry , Catechin/isolation & purification , Flavonoids/isolation & purification , Flavonols/isolation & purification , Plants, Medicinal/chemistry , Catechin/analogs & derivatives , Catechin/chemistry , Chromatography, Gel , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/isolation & purification , Flavonoids/chemistry , Flavonols/chemistry , Magnetic Resonance Spectroscopy , Mass Spectrometry , Plant Stems/chemistryABSTRACT
OBJECTIVE: To study the chemical constituents of a Tibetan medicine Meconopsis quintuplinervia. METHOD: Column chromatographic techniques were applied to isolate constituents. A combination of IR, MS and NMR spectroscopy was used to identify structures of constituents. RESULT: Twelve compounds were isolated from the ethanolic extract and their structures were elucidated as quercetin 3-O-beta-D-glucopyranoside (I), quercetin 3-O-beta-D-galactopyranosyl-(1-->6)-glucopyranoside (II), kaempferol 3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside (III), isorhamnetin 3-0-beta-D-galactopyranosyl-(1-->6)-beta-D-glucopyranoside (IV), caffeic acid (V), protocatechuic acid (VI), p-hydroxycinnamic (VII), 2-(3,4-dihydroxyphenyl )-ethyl-O-beta-D-glucopyranoside (VIII), p-hydroxybenzoyl-beta-D-glucopyranoside (IX), 4-O-beta-D-glucopyranosyl-(Z)-p-coumaric acid (X), 5, 7-dihydroxy-4H-4-chromenone (XI), daucosterol (XII). CONCLUSION: Ten compounds were isolated from this genus for the first time except for XI and XII.
Subject(s)
Caffeic Acids/isolation & purification , Glucosides/isolation & purification , Hydroxybenzoates/isolation & purification , Papaveraceae/chemistry , Plants, Medicinal/chemistry , Quercetin/analogs & derivatives , Caffeic Acids/chemistry , Glucosides/chemistry , Hydroxybenzoates/chemistry , Quercetin/chemistry , Quercetin/isolation & purificationABSTRACT
Flavonol 3,7-di-O-glycosides were investigated by negative ion electrospray ionization tandem mass spectrometry using a quadrupole linear ion trap (LIT) mass spectrometer. The results indicate that the fragmentation behavior of flavonol 3,7-di-O-glycosides is substantially different from that of their isomeric mono-O-diglycosides. In order to characterize a flavonoid as a flavonol 3,7-di-O-glycoside, both [Y3(0) - H]-* and [Y(0) - 2H]- ions should be present in [M - H]- product ion spectrum. The MS(3) product ion spectra of Y3(0)-, [Y3(0) - H]-* and Y7(0)- ions generated from the [M - H]- ion provide sufficient structural information for the determination of glycosylation position. Furthermore, the glycosylation positions are determined by comparing the relative abundances of Y3(0)- and Y7(0)- ions and their specific fragmentation patterns with those of flavonol mono-O-glycosides. In addition, a [Y3(0) - H]-* ion formed by the homolytic cleavage of 3-O glycosidic bond with high abundance points to 3-O glycosylation, while a [Y(0) - 2H]- ion formed by the elimination of the two sugar residues is consistent with glycosylation at both the 3-O and 7-O positions. Investigation of negative ion ESI-MS(2) and MS(3) spectra of flavonol O-glycosides allows their rapid characterization as flavonol 3,7-di-O-glycoside and their differentiation from isomeric mono-O-diglycosides, and also enables their direct analysis in crude plant extracts.