Eremosides A – C,New Iridoid Glucosides from Eremostachys loasifolia

Eremosides A–C ( 1 – 3 ), three new iridoid glucosides, were isolated from the AcOEt‐soluble fraction of the EtOH extract of the whole plant of Eremostachys loasifolia, along with buddlejoside B ( 4 ), 10‐O‐benzoylcatalpol ( 5 ), and pakiside A ( 6 ) reported for the first time from this species. The structures of these compounds were elucidated by spectroscopic data including 2D‐NMR, FAB‐MS, ESI‐MS, as well as by acid and basic hydrolyses.     

Screening potential antagonists of epidermal growth factor receptor from Marsdenia tenacissima via cell membrane chromatography model assisted by HPLC–ESI–IT–TOF–MS

Marsdenia tenacissima, or Tongguanteng in Chinese, is a traditional Chinese herb and has a broad application in clinical practice for its pharmacological effects of treating asthma, pneumonia, tonsillitis, pharyngitis tumors, etc. However, few studies have reported the screening of the active components of this medicine for tumor therapy. In this work, a two‐dimensional analytical system was developed to screen antagonists of epidermal growth factor receptor (EGFR) from M. tenacissima. A fraction was retained on the EGFR cell membrane chromatography (CMC) column, separated and identified as tenacissoside G (TG), tenacissoside H (TH) and tenacissoside I (TI) by two‐dimensional HPLC–IT–TOF–MS. Molecular docking and 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2‐H‐tetrazolium bromide (MTT) assay were carried out to assess the activity of TS (including TG, TH and TI). Molecular docking results showed that the binding mode of TS on EGFR is similar to that of gefitinib. The MTT assay demonstrated that gefitinib and TS (especially TI) could inhibit the growth of EGFR highly expressed cell lines in a dose‐dependent manner in the range of 5–50 μmol/L. In conclusion, the two‐dimensional EGFR/CMC–HPLC–IT–TOF–MS system could be a useful approach in drug discovery from traditional Chinese medicines for searching for potential antitumor candidates.     

Glycopentosides D – F,Three New Phenolic Glycosides from Glycosmis pentaphylla

A phytochemical investigation of the BuOH‐soluble fraction of the EtOH extract from the stems of Glycosmis pentaphylla resulted in the isolation of three new phenolic glycosides, glycopentosides D–F ( 1 – 3 , resp.). Their structures were determined by using spectroscopic analysis including UV, ¹H‐ and ¹³C‐NMR, DEPT, COSY, ROESY, HMBC, HSQC, HR‐ESI‐MS, and acid hydrolysis.     

Spectroscopical UV–Vis implications of an intramolecular η2–Mg coordination in bacteriochlorophyll–a from the Fenna–Matthews–Olson complex

Chlorophylls and their related compounds prominently feature a Mg²⁺ ion in the center of a porphyrine, with an intermolecular fifth coordination usually observed to place the ion out of the macrocyclic plane. Herein, we assess the role of a potential intramolecular η²–(C = C)Mg interaction and compare it to the intermolecular coordination from the Hystidine groupt to Mg²⁺ for Bacterichlorophyll–a (Bchl–a), the main photosynthetic pigment in the Fenna–Matthews–Olson complex present in green and purple bacteria. The influence of this fifth coordination on the UV‐Vis spectroscopy (CAM‐B3LYP/cc‐pVDZ), and the concomitant change in geometry around Mg in Bchl–a from planar to pyramidal is assessed by the quantum theory of atoms in molecules based non–covalent interactions scheme and through energetic analysis via natural bond orbital population methods at the M06‐2X/cc‐pVDZ and compared to the reference multi–hapto compound, magnesocene, Cp₂Mg.     

Screening and analysis of metabolites in rat urine after oral administration of Apocynum venetum L. extracts using HPLC–TOF‐MS

HPLC with diode array detection and ESI‐TOF‐MS was used for the study of the constituents in Apocynum venetum L. extracts and the metabolites in rat urine after oral administration of A. venetum L. extracts. A formula database of the known constituents in A. venetum L. was established, and 21 constituents were rapidly identified by accurately matching their molecular masses with the formulae of the compounds in the database. Furthermore, 34 metabolites were detected and elucidated in the rat urine. The scientific and plausible biotransformation pathways of the flavonoid components in A. venetum L. were also proposed together with the presentation of clues for potential mechanisms of bioactivity. This specific and sensitive HPLC–ESI‐TOF‐MS method can be used to identify the chemical components in the extracts of A. venetum L. and their metabolites in rat urine. This method can also be used to reveal the possible metabolic mechanisms of action of the extract components in vivo.     

UPLC–Q‐TOF–MS and UPLC–MS/MS methods for metabolism profiles and pharmacokinetics of major compounds in Xuanmai Ganjie Granules

Xuanmai Ganjie Granules (XMGJ), a widely used Chinese herbal formula in the clinic, is used for treatment of sore throats and coughs. Despite the chemical constituents having been clarifying by our previous studies, both of the metabolism and pharmacokinetic studies of XMGJ are unclear. This study aimed to explore the disposition process of XMGJ in vivo. A sensitive and selective ultra‐high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry (UPLC–Q‐TOF–MS) method was developed to analyze the absorbed components and metabolites in rat plasma and urine after oral administration of XMGJ. A total of 42 absorbed components, including 16 prototype compounds and 26 metabolites, were identified or tentatively characterized in rat plasma and urine after oral administration of XMGJ. Moreover, the pharmacokinetic studies of five compounds of XMGJ were investigated using ultra‐high liquid chromatography with tandem mass spectrometry method. The results indicated that liquiritin, harpagoside, glycyrrhetic acid, liquiritigenin, formononetin and their metabolites might be the major components involved in the pharmacokinetic and metabolism process of XMGJ. This research showed a comprehensive investigation of XMGJ in vivo, which could provide a meaningful basis for further material basis and pharmacological as well as toxicological research.     

Study of pancreatic lipase inhibition kinetics and LC–QTOF–MS‐based identification of bioactive constituents of Momordica charantia fruits

The different parts of Momordica charantia have been reported to have several therapeutic applications against hyperglycemia and hypercholesterolemia associated with pancreatic lipase (PL). Inhibition of this enzyme prevents the absorption of dietary triglyceride in the intestine, and thus exerts an anti‐obesity effect. This study aimed to investigate the bioactive constituents of the fruits of M. charantia (MCF) extract and fractions against pancreatic PL followed by study of their inhibition kinetics. The PL inhibitory assay was performed spectrophotometrically by measuring the change in absorbance of the products at 405 nm, using p‐nitrophenylcaprylate as substrate. The results indicated that the ethyl acetate fraction of MCF (EFMC) offered significant, dose‐dependent inhibition against PL, compared with the positive control, Orlistat. The enzyme kinetics study revealed the inhibition to be a mixed type in nature. Additionally, the total phenol and flavonoid content of the fractions was estimated. A positive correlation between phenolic content of EFMC and its PL inhibitory activity was established statistically, which implied that higher inhibition potential was contributed by the phenolic compounds. The identification of the bioactive constituents was further confirmed by LC–QTOF–MS study. This finding suggested that phenolic compounds of MCF can serve as functional food components to address obesity‐related disorders linked with PL.     

Chemical fingerprint analysis and metabolic profiling of 50% ethanol fraction of Lomatogonium rotatum by ultra‐performance liquid chromatography/quadrupole–time of flight mass spectrometry

Lomatogonium rotatum (L.) Fries ex Nym (L. rotatum), a member of Gentianaceae, is an important mongolian medicine in China used to treat febrile diseases in liver and gallbladder. The aim of present study was to investigate the chemical constituents and metabolites of the 50% ethanol fraction of L. rotatum (50EtLR). Firstly, the extract of L. rotatum was partitioned by macroporous resin to obtain the target fraction (50EtLR), then several compounds were isolated from 50EtLR to obtained the standards for further analysis of chemical constituents of 50EtLR. Secondly, the chemical constituents of 50EtLR were characterized using the ultra‐high performance liquid chromatography coupled with quadrupole–time‐of‐flight mass spectrometry (UHPLC–Q‐TOF–MS/MS). Finally, prototype constituents and related metabolites were analyzed after orally administerng 50EtLR to rats. As a result, a new compound, 6‐O‐[β‐d ‐xylopyranosyl‐(1 → 6)‐O‐β‐d ‐glucopyranosyl]‐1,4,8‐trimethoxyxanthone ( 6 ) along with seven known compounds ( 1–5 , 7 and 8 ) were isolated from the 50EtLR, 92 components were either unambiguously or tentatively identified. Additionally, 34 prototype constituents and 112 metabolites in rat plasma along with 32 prototype constituents and 53 metabolites in rat liver were tentatively identified. Therefore, xanthones and flavonoids were the main chemical constituents of 50EtLR and sulfation and glucuronidation are the main enzyme‐induced metabolic pathways involved post‐administration.     

Dapholidins A – C,New Isomeric Biisoflavonoids From Daphne oleoides

Three new isomeric biisoflavonoids, dapholidins A–C ( 1 – 3 , resp.), have been isolated from the AcOEt‐soluble fraction of the MeOH‐soluble extract of the roots of Daphne oleoides, along with the known compounds daphwazirin ( 4 ), daphnetin 8‐O‐β‐D ‐glucopyranoside ( 5 ), daphnin ( 6 ), daphneticin 4″‐O‐β‐D ‐glucopyranoside ( 7 ), and 6,7‐dihydroxy‐3‐methoxy‐8‐[2‐oxo‐2H‐1‐benzopyran‐7‐(O‐β‐D ‐glucopyranosyl)‐8‐yl]‐2H‐1‐benzopyran‐2‐one ( 8 ). The structures of the new compounds were determined by spectroscopic analyses, including 1D‐ and 2D‐NMR.     

Petrorhagiosides A – D,New γ‐Pyrone Derivatives from Petrorhagia saxifraga Link

Four novel γ‐pyrone (=4H‐pyran‐4‐one) metabolites, petrorhagiosides A–D, along with four known analogs, have been isolated from the MeOH extract of Petrorhagia saxifraga, a perennial herbaceous plant typical of Mediterranean vegetation. The structures of the new compounds were established on the basis of extensive spectroscopic analyses including 1D‐ an 2D‐NMR (¹H,¹H‐DQ‐COSY, TOCSY, HSQC, CIGAR‐HMBC, and HSQC‐TOCSY) experiments.     

The chemical composition and bonding structure of B–C–N–H thin films deposited by reactive magnetron sputtering

The chemical composition and bonding structures of B–C–N–H films fabricated by medium frequency magnetron sputtering, with N₂+CH₄+Ar gas mixture sputtering the boron target, were investigated. XPS and FTIR spectrometric analyses show that the increase of CH₄ flow rate during deposition causes an increase of the C content in the films. The increase in the CH₄ flow rate promotes an increase in the B–C, C–N single and C?N double bonds which are the components of the hybridized B–C–N bonding structure. From the results of Raman spectroscopy analysis, it is seen that the intensity of the D band of the films' Raman spectrum decreases with increasing CH₄ flow rate, indicating a decrease of the sp²‐phase content or the sp² C cluster size. The decreases of I_D/I_G also reflect the formation of more boron‐ or nitrogen‐ bound sp³‐coordinated carbons in the films. Copyright © 2009 John Wiley & Sons, Ltd.     

Plasma metabonomics study on toxicity biomarker in rats treated with Euphorbia fischeriana based on LC–MS

Lang‐du (LD) has been traditionally used to treat human diseases in China. Plasma metabolic profiling was applied in this study based on LC–MS to elucidate the toxicity in rats induced by injected ethanol extract of LD. LD injection was given by intraperitoneal injection at doses of 0.1, 0.05, 0.025 and 0 g kg^?1 body weight per day to rats. The blood biochemical levels of alanine aminotransferase, direct bilirubin, creatinine, serum β2‐microglobulin and low‐density lipoprotein increased in LD‐injected rats, and the levels of total protein and albumin decreased in these groups. The metabolic profiles of the samples were analyzed by multivariate statistics analysis, including principal component analysis, partial least squares discriminant analysis and orthogonal projection to latent structures discriminate analysis (OPLS‐DA). The metabolic characters in rats injected with LD were perturbed in a dose‐dependent manner. By OPLS‐DA, 18 metabolites were served as the potential toxicity biomarkers. Moreover, LD treatment resulted in an increase in the p‐cresol, p‐cresol sulfate, lysophosphatidylethanolamine (LPE) (18:0), LPE (16:0), lysophosphatidylcholine (16:0) and 12‐HETE concentrations, and a decrease in hippuric acid, cholic acid and N‐acetyl‐l ‐phenylalanine. These results suggested that chronic exposure to LD could cause a disturbance in lipids metabolism and amino acids metabolism, etc. Therefore, an analysis of the metabolic profiles can contribute to a better understanding of the adverse effects of LD. Copyright © 2016 John Wiley & Sons, Ltd.     

Qualitative and quantitative determination of Atractylodes rhizome using ultra‐performance liquid chromatography coupled with linear ion trap–Orbitrap mass spectrometry with data‐dependent processing

A quick and effective workflow based on ultra‐performance liquid chromatography coupled with electron spray ionization and LTQ‐Orbitrap mass spectrometry (UPLC‐LTQ‐Orbitrap MS) was established for compositional analysis and screening of the characteristic compounds of three species of Atractylodes rhizome for quality evaluation. This technique was employed to determine the seven main components in Atractylodes rhizome samples. Ultimately, 78 constituents were identified; of these, seven characteristic compounds were selected for species discrimination, comprising atractylodin (63), atractylenolide I (43), atractylenolide II (49), atractylenolide III (53), atractylon (69), methyl‐atractylenolide II (54) and (4E,6E,12E)‐tetradecadecatriene‐8,10‐diyne‐1,3‐diacetate (59). The seven main compounds, including six characteristic compounds, were simultaneously determined in 29 batches of Atractylodes rhizome samples. Thus, the method validation showed acceptable results. Quantitative analysis showed significantly different contents of the seven main components among the three species of Atractylodes rhizome, which indicates possible distinctions in the pharmacological effects. This established method can simultaneously provide qualitative and quantitative results for compositional characterization of Atractylodes rhizomes and for quality control.     

Filler–polymer interactions in both silica and carbon black‐filled styrene–butadiene rubber compounds

Bound rubber in a filled rubber compound is formed by physical adsorption and chemisorption between the rubber and the filler. Styrene–butadiene rubber (SBR) is composed of four components of styrene, cis‐1,4‐, trans‐1,4‐, and 1,2‐units. Filler–polymer interactions in both silica and carbon black‐filled SBR compounds were studied by analyzing microstructures of the bound rubbers with pyrolysis‐gas chromatography. Differences in the filler–polymer interactions of the styrene, cis‐1,4‐, trans‐1,4‐, and 1,2‐units were investigated. The filler–polymer interactions of the butadiene units were found to be stronger than that of the styrene unit. The interactions of the cis‐1,4‐ and trans‐1,4‐units were stronger with carbon black than with silica, whereas the 1,2‐unit interacted more strongly with silica than with carbon black. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 439–445, 2001     

Caragisides A – C,New Isoflavone Glucosides from Caragana conferta with Inhibition of Platelet Aggregation

Caragisides A–C ( 1 – 3 , resp.), three new isoflavone glucosides, were isolated from the BuOH sub‐fraction of the EtOH extract of the whole plant of Caragana conferta, along with ononoside ( 4 ), reported for the first time from this species. The structures of the new compounds were elucidated by spectroscopic techniques including MS and 2D‐NMR spectroscopy. Compounds 1 – 3 showed significant inhibition of platelet aggregation.     

Pd(II) complexes of Schiff bases and their application as catalysts in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions

Schiff bases of 2‐(phenylthio)aniline, (C₆H₅)SC₆H₄N?CR (R = (o‐CH₃)(C₆H₅), (o‐OCH₃)(C₆H₅) or (o‐CF₃)(C₆H₅)), and their palladium complexes (PdLCl₂) were synthesized. The compounds were characterized using ¹H NMR and ¹³C NMR spectroscopy and micro analysis. Also, electrochemical properties of the ligands and Pd(II) complexes were investigated in dimethylformamide–LiClO₄ solution with cyclic and square wave voltammetry techniques. The Pd(II) complexes showed both reversible and quasi‐reversible processes in the ?1.5 to 0.3 V potential range. The synthesized Pd(II) complexes were evaluated as catalysts in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions. Copyright © 2015 John Wiley & Sons, Ltd.     

Identification of volatile compounds of Atractylode lancea Rhizoma using supercritical fluid extraction and GC–MS

Supercritical fluid was used to extract volatile components from the rhizoma of Atractylode lancea (A. lancea). An orthogonal array design (OAD), L₉ (3)⁴, was employed as a chemometric method for the optimization of the supercritical fluid extraction (SFE) of volatile compounds from the herbal medicine. Four parameters, namely, pressure, temperature, dynamic extraction time, and flow rate of CO₂, were studied and optimized by a three‐level OAD in which the interactions between the parameters were neglected. These compounds were identified according to their retention times and mass spectra by GC–MS. A total of 30 compounds of SFE extracts were identified. Atractylon (8.63%), hinesol (1.44%), β‐eudesmol (6.64%), elemol (0.42%), and atractydin (13.92%) were the major sesquiterpenes identified in A. lancea SFE extracts.     

Dimorphamides A – C,New Polyphenolic Amides from Atriplex dimorphostagia

Dimorphamides A–C ( 1 – 3 , resp.), three new polyphenolic amides, have been isolated from the BuOH‐soluble fraction of the whole plant of Atriplex dimorphostagia, along with two known compounds, thymidine and N‐[(E)‐feruloyl]tyramine. Their structures have been determined on the basis of spectral studies.     

Validated LC‐MS/MS method for the simultaneous determination of hyperoside and 2′′–O‐galloylhyperin in rat plasma: application to a pharmacokinetic study in rats

An LC‐MS/MS method was developed for the first time to simultaneously determine hyperoside and 2′′–O‐galloylhyperin, two major components in Pyrola calliantha extract, in rat plasma. Following extraction by one‐step protein precipitation with methanol, the analytes were separated on a Venusil MP‐C₁₈ column within 2 min, using methanol–water–formic acid (50:50:0.1, v/v/v) as the mobile phase at a flow rate of 0.4 mL/min. Detection was performed on electrospray negative ionization mass spectrometry by multiple‐reaction monitoring of the transitions of 2′′–O‐galloylhyperin at m/z 615.1 → 301.0, of hyperoside at m/z 463.1 → 300.1, and of internal standard at m/z 415.1 → 295.1. The limits of quantification were 2 ng/mL for both hyperoside and 2′′–O‐galloylhyperin. The precisions were <13.1%, and the accuracies were between ?9.1 and 5.5% for both compounds. The method was successfully applied in pharmacokinetic studies following intravenous administration of the total flavonoids of P. calliantha extract in rats. Copyright © 2013 John Wiley & Sons, Ltd.