Matrix-assisted laser desorption/ionization(MALDI)mass spectrometry imaging(MSI)is an attractive technology for the visualization of metabolite distributions in tissues.However,detection and identification of low-abun...Matrix-assisted laser desorption/ionization(MALDI)mass spectrometry imaging(MSI)is an attractive technology for the visualization of metabolite distributions in tissues.However,detection and identification of low-abundance or poorly ionized metabolites remains challenging.Although on-tissue chemical derivatization(OTCD)holds great promise for improving MALDI MS detection sensitivity and selectivity by modification of specific chemical groups,the available methods for subsequent metabolite annotation are limited.Herein,a laser-assisted chemical transfer(LACT)-based parallel OTCD strategy was established for visualizing and annotating carbonyl metabolites in murine brain tissues.Girard's T and Girard's P reagents were applied for parallel OTCD to generate the characteristic m/z pairs with a 19.969 Da mass shift(±0.020 Da tolerance)for rapid recognition of derivatized metabolites.The similarity of spatial distribution patterns of each m/z pair was further statistically evaluated to remove the ambiguous annotations due to the occurrence of interference compounds.As a result,90 ion pairs were annotated as candidate carbonyl metabolites,66 were previously known and 24 were potential unreported carbonyls.Furthermore,the spatial alterations of carbonyl metabolites in the ischemic rat brain were successfully visualized and characterized,including small molecule aldehydes and ketones,long-chain fatty aldehydes,and monosaccharides.This further emphasizes great potential of parallel OTCD strategy for efficient and confident molecular annotation of spatial submetabolomics data associated with brain diseases.展开更多
[Objective] This study aimed to establish a pre-column derivatization HPLC method for the identification and analysis of monosaccharide composition of Pu-erh tea polysaccharide. [Method] Pu-erh tea polysaccharide was ...[Objective] This study aimed to establish a pre-column derivatization HPLC method for the identification and analysis of monosaccharide composition of Pu-erh tea polysaccharide. [Method] Pu-erh tea polysaccharide was extracted using the wa- ter extraction method, further isolated and purified by DEAE cellulose-52 columns. The obtained tea polysaccharide and four components TPS1, TPS2, TPS3 and TPS, were first derived by 1-phenyl-3-methyl-5-pyrazolone （PMP）, and then the PMP derivatives of monosaccharide were analyzed by high performance liquid chromatog- raphy （HPLC）. [Result] Pu-erh tea polysaccharide contained eight kinds of monosac- chaddes （mannose, rhamnose, glucuronic acid, galacturonic acid, grucose, galactose, arabinose, fucose）, without xylose; so it was the same with TPS1; each of TPS2, TPS3 and TPS4 contained seven monosaccharides, while no fucose. [Conclusion] This method is simplified and rapid, which can be used to determine the monosac- charide composition of Pu-erh tea polysaccharide and monosaccharide content.展开更多
Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extract...Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extracted from the dog serum using dichlromethane followed by derivatization with DNBF for 20 min at 100℃. The solvent was then evaporated at 60℃ under nitrogen, and the residue was taken up in 100 μL of mobile phase consisting of acetonitrile water (75∶30, v/v). The separation was performed on a Hypersil BDS C18 column with a flow rate of 0 8 mL·min -1 , and the ultraviolet detector wavelength was set at 350 nm. Results Extraction recovery ranged from 75.9% to 83.2%, and methodological recovery was between 96.5% and 109.3%. Within day RSD ranged from 1.5% to 6.3%, and inter day RSD was between 2 9% and 14.8%. The method showed good linearity (R=0.9998). Conclusion The method was simple, convenient and sensitive. The reaction of derivatization was reproducible.展开更多
A pre-column derivatization HPLC method for the determination of peimine(P)and peiminine(PE)in Bulbus Fritillariae has been developed. Under the derivatization conditions optimized,the calibration curve is Y1=-3.83...A pre-column derivatization HPLC method for the determination of peimine(P)and peiminine(PE)in Bulbus Fritillariae has been developed. Under the derivatization conditions optimized,the calibration curve is Y1=-3.83×103+1.33 ×105X1,r=0.998 for P and Y2=-7.86 × 102+6.33 × 104X2,r=0995 for PE,where Y is the peak area and X is the weight of the alkaloid; the average recovery is 98.0%(n=5, RSD=2.1%) for P and 101.0%(n=5,RSD=4.1%)for PE,the linear range is from 0.504 μg to 3.126μg for P and from 0.520μgto 3.328μgfor PE,respectively. Results of the determination of the two alkaloids in several samples of different Fritillaria species from various parts ofthe country are presented.The results suggest that P and PE are two major chemical constituents in bulbs of different Fritillaria species,and that the method developed is generally appli-cable to the determination of the hydroxy group on aliphatic fused ring systems without steric hin-drance.展开更多
Lignin serves as one of the most important molecular fossils for tracing Terrestrial Organic Matters （TOMs） in marine environment. Extraction and derivatization of lignin oxidation products （LOPs） are crucial for ...Lignin serves as one of the most important molecular fossils for tracing Terrestrial Organic Matters （TOMs） in marine environment. Extraction and derivatization of lignin oxidation products （LOPs） are crucial for accurate quantification of lignin in marine sediment. Here we report a modification of the conventional alkaline cupric oxide （CuO） oxidation method, the modification consisting in a solid phase extraction （SPE） and a novel on-column derivatization being employed for better efficiency and reproducibility. In spiking blanks, recoveries with SPE for the LOPs are between 77.84% and 99.57% with relative standard deviations （RSDs） ranging from 0.57% to 8.04% （n=3）, while those with traditional liquid-liquid extraction （LLE） are from 44.52% to 86.16% With RSDs being from 0.53% to 13.14% （n=3）. Moreover, the reproducibility is greatly improved with SPE, with less solvent consumption and shorter processing time. The average efficiency of on-column derivatization for LOPs is 100.8%±0.68%, which is significantly higher than those of in-vial or in-syringe derivatization, thus resulting in still less consumption of derivatizing reagents.Lignin in the surface sediments sampled from the south of Yangtze River estuary, China, was determined with the established method. Recoveries of 72.66% to 85.99% with standard deviation less than 0.01mg/10g dry weight are obtained except for p-hydroxybenzaldehyde. The lignin content ∑8 （produced from 10g dry sediment） in the research area is between 0.231 and 0.587mg. S/V and C/V ratios （1.028 ± 0.433 and 0.192±0.066, respectively） indicate that the TOMs in this region are originated from a mixture of woody and nonwoody angiosperm plants; the high values or （Ad/Al）v suggest that the TOMs has been highly degraded.展开更多
A reversed-phase high-performance liquid chromatographic （RP-HPLC） method was established for the determination of the enantiomers of 7 aryloxy aminopropanol drugs （atenolol, sotalol, celiprolol, carvedilol, metopr...A reversed-phase high-performance liquid chromatographic （RP-HPLC） method was established for the determination of the enantiomers of 7 aryloxy aminopropanol drugs （atenolol, sotalol, celiprolol, carvedilol, metoprolol, propranolol and propafenone） in transport medium. The method involved liquid-liquid extraction of chiral drugs from transport medium, and employed 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate （GITC, 1.0 mg/mL in acetonitrile） as a pre-column chiral derivatization reagent. After derivatization, the products were separated on an Agilent Zorbax C8 column （150 min×4.6 mm, 5 μm） at 25 ℃. The mobile phase consisted of a mixture of acetonitrile and 0.01 M phosphate buffer （pH 3.5）. The present methods were specific for the determination of enantiomers of each chiral drug. The absolute recoveries of the enantiomers and internal standards were 〉78%. The relative recoveries of the enantiomers were approximately 100%. The intra- and inter-day variations were 〈 15%. The method was reproducible and sufficiently sensitive to determine the enantiomers of seven aryloxy aminopropanol drugs in transport medium. The method could be used to study the transport of atenolol, sotalol, celiprolol, carvedilol, metoprolol, propranolol and propafenone.展开更多
Direct infusion mass spectrometry(DIMS) is a powerful technique in clinical diagnosis for screening neonatal amino acid metabolic disorders from dried blood spots(DBS).However,DIMS sometimes generated false-positive r...Direct infusion mass spectrometry(DIMS) is a powerful technique in clinical diagnosis for screening neonatal amino acid metabolic disorders from dried blood spots(DBS).However,DIMS sometimes generated false-positive results for analysis of amino acids.In this work,we utilized a stable isotope derivatization method,combining with liquid chromatography tandem mass spectrometry(SID-LC-MS),to improve the specificity for screening amino acids in DBS specimens.A pair of isotope reagents,p-(dimethylamino)phenyl isothiocyanate(DMAP-NCS) and 4-isothiocyanato-N,N-bis(methyl-[2H2])aniline([2H4]DMAP-NCS),was synthesized and used to label amino acids in DBS specimens.The [2H4]DMAP-NCS labelled amino acid standards were used as internal standards to compensate the matrix effect.This method was validated by measuring linearity,recovery and accuracy.The results showed that the developed SID-LC-MS method can be used for sensitive and selective determination of 12 diagnostically important amino acids in DBS specimens.展开更多
On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI)...On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI).Combination OTCD and MSI provides a novel strategy for visualizing previously undisclosed metabolic heterogeneity in tumor.Herein,we present a method to visualize heterogeneous metabolism of oxylipins within tumor by coupling OTCD with airflow-assisted desorption electrospray ionization(AFADESI)-MSI.Taking Girard’s P as a derivatization reagent,easily ionized hydrazide and quaternary amine groups were introduced into the structure of carbonyl metabolites via condensation reaction.Oxylipins,including 127 fatty aldehydes(FALs)and 71 oxo fatty acids(FAs),were detected and imaged in esophageal cancer xenograft with AFADESI-MSI after OTCD.Then t-distributed stochastic neighbor embedding and random forest were exploited to precisely locate the distribution of oxylipins in heterogeneous tumor tissue.With this method,we surprisingly found almost all FALs and oxo FAs significantly accumulated in the core region of tumor,and exhibited a gradual increase trend in tumor over time.These results reveal spatiotemporal heterogeneity of oxylipins in tumor progression,highlighting the value of OTCD combined with MSI to gain deeper insights into understanding tumor metabolism.展开更多
A selective precolumn derivatization liquid chromatography–tandem mass spectrometric (LC–MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was...A selective precolumn derivatization liquid chromatography–tandem mass spectrometric (LC–MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was derivatized by o-phthalaldehyde/3-mercaptopropionic acid. Chromatographic separation was performed on a Phenomenex ODS column (150 mm 4.6 mm, 5 mm) using linear gradient elution by a mobile phase consisting of methanol (A), and an aqueous solution containing 0.2% ammonium acetate and 0.1% formic acid (B) at a flow rate of 1 mL/min. Tolterodine tartrate was used as the internal standard (IS). With protein precipitation by acetonitrile and then the simple one-step derivatization, a sensitive bio-assay was achieved with the lower limit of quantitation (LLOQ) as low as 12 ng/mL for plasma. The standard addition calibration curves suitable for clinical sample analysis showed good linearity over the range of 0.012–8.27 mg/mL in plasma and 1.80–84.1 mg/mL in urine. The fully validated method has been successfully applied to a pharmacokinetic study of compound glucosamine sulfate dispersible tablets in health Chinese volunteers receiving single oral doses at 500, 1000 and 1500 mg of glucosamine sulfate, as well as multiple oral doses of 500 mg t.i.d. for 7 consecutive days.展开更多
Now increasing chemical modifications are discovered on genomic DNA and RNA. Up to date, more than150 chemical modifications are identified in nucleic acids. These chemical modifications do not change the sequence of ...Now increasing chemical modifications are discovered on genomic DNA and RNA. Up to date, more than150 chemical modifications are identified in nucleic acids. These chemical modifications do not change the sequence of DNA and RNA, but alter their structures and biochemical properties, and eventually control or regulate the spatial and temporal expression of genes. Elucidation of the functional roles of these modifications is vital to our understanding of living organisms. However, the modifications in DNA and RNA generally have extremely low abundance in vivo. Therefore, sensitive and specific detection methods are essential to decipher the functional roles of these modifications. Chemical derivatization in combination with mass spectrometry(MS) analysis has been proved to be a promising strategy to efficiently analyze these modifications in DNA and RNA. In the last several years, many chemical derivatization-MS-based analytical methods were established for the sensitive and effective analysis of nucleic acid modifications. In this review, we summarize the recent advances for deciphering modifications in DNA and RNA by chemical derivatization-MS analysis. We hope this review can stimulate the future studies of DNA and RNA modifications.展开更多
The enantioselective assay for S(+)- and R(-)-propafenone (PPF) in human urine that developed in this work involves extraction of propafenone from human urine and using S(+)-propafenone as internal standard, chiral de...The enantioselective assay for S(+)- and R(-)-propafenone (PPF) in human urine that developed in this work involves extraction of propafenone from human urine and using S(+)-propafenone as internal standard, chiral derivatization with 2,3,4,6-tetra-O-b-D-glucopranosyl isothiocyanate, and quantitation by an RP-HPLC system with UV detection (l=220 nm). A baseline separation of propafenone enantiomers was achieved on a 5-mm reverse phase ODS column, with a mixture of methanol:water:glacial acetic acid (25:12:0.02,v/v) as mobile phase. There was good linear relationship from 24.9 ng/ml to 1875.0 ng/ml for both of enantiomers. The regression equations of the standard curves based on CS-PPF (or CR-PPF ) versus ratio of AS-PPF/AS (or AR-PPF/AS ) were y=0.0032x-0.081, (r=0.999) for S-PPF and y=0.0033x+0.0039, (r=0.998) for R-PPF, respectively. The method抯 limit of detection was 12.5 ng/ml for both enantiomers, and the method抯 limit of quantitation was 28.20.52 ng/ml for S-PPF, 30.40.53 ng/ml for R-PPF (RSD<8%, n=5). The analytical method yielded average recovery of 98.9% and 100.4% for S-PPF and R-PPF, respectively. The relative standard deviation was no more than 6.11% and 6.22% for S-PPF and R-PPF, respectively. The method enabled study of metabolism of S(+)- and R(-)-propafenone in human urine. The results from 7 volunteers administered 150 mg racemic propafenone indicated that propafenone enantiomers undergo stereoselective metabolism and that in the human body, S(+)-propafenone is metabolized more extensively than R(-)- propafenone.展开更多
Inosine is a vital RNA modification across three kingdoms of life.It has been demonstrated that inosine plays important roles in modulation of the fate of RNAs.In the current study,we developed a highly sensitive meth...Inosine is a vital RNA modification across three kingdoms of life.It has been demonstrated that inosine plays important roles in modulation of the fate of RNAs.In the current study,we developed a highly sensitive method to determine inosine in a single cell by N-cyclohexyl-N’-β-(4-methylmorpholinium)ethylcarbodiimide p-toluenesulfonate(CMCT)derivatization in combination with mass spectrometry analysis.The results showed that the detection sensitivity of inosine was increased by 556-fold after CMCT derivatization,with the limit of detection(LOD)being 4.5 amol.With the established method,we could detect inosine from 13.0 pg of total RNA of HEK293T cells.Meanwhile,inosine in RNA from a single cell could also be clearly detected due to the improved detection sensitivity.Moreover,we found the level of inosine in RNA of sleep-deprived mice was significantly increased compared to the control mice,indicating that inosine is associated with sleep behavior and might be a potential indicator of sleep disorder.Taken together,the chemical derivatization coupled with mass spectrometry analysis offers a valuable tool in determination of endogenous RNA modifications in a single cell,which should benefit the functional study of RNA modification in rare clinical samples.展开更多
A sensitive and rapid high performance liquid chromatography-mass spectrometry(HPLC-MS)method was developed and validated for simultaneous quantifcation of ten steroid hormones,including estrogens,androgens,progestero...A sensitive and rapid high performance liquid chromatography-mass spectrometry(HPLC-MS)method was developed and validated for simultaneous quantifcation of ten steroid hormones,including estrogens,androgens,progesterones,and corticosteroids four classes of steroids.The following ten steroid hormones were analyzed:progesterone,21-deoxycortisol,estrone,4-androstenedione,testosterone,dihydro-testosterone,androstenone,dehydroepiandrosterone,corticosterone and cortisone.Stable deuterated isotopes were used as internal standards for quantifcation.Sample preparation with and without derivatization were performed after liquid-liquid extraction,and the corresponding results were compared according to sensitivity and selectivity.Hydroxylamine derivatization was found to improve the ionization efciency of the analytes for electrospray ionization MS analysis.The gradient of mobile phase and experimental parameters for HPLC separation were optimized.The lower limits of quantifcation were in the range of 0.05-5 ng mL^(−1) with wide linear range for the ten steroid hormones.The intra-day precision<11.1%and recovery of 84.5-120% with negligible matrix efect were achieved,where within the acceptance limits of the FDA guideline.Total HPLC-MS analysis time was 6 min.This method enables simultaneous quantifcation of steroids in human serum.It will be helpful for the serum steroid profling in order to understand various endocrinology diseases.展开更多
[Objectives] This study was conducted to optimize the determination conditions of amino acids from abalone. [Methods] The sample was treated by acid hydrolysis method and subjected to 2,4-2 nitro fluorobenzene column ...[Objectives] This study was conducted to optimize the determination conditions of amino acids from abalone. [Methods] The sample was treated by acid hydrolysis method and subjected to 2,4-2 nitro fluorobenzene column derivatization. The amino acid content in abalone was determined by HLPC,and the nutritional value of the amino acids was evaluated with egg protein model put forward by Institute of Nutrition and Food Hygiene,Chinese Academy of Preventive Medicine. [Results] Abalone contains full amino acids. According to the FAO/WHO ideal,it is a high-quality protein source and suitable for supplement of protein source for human body. [Conclusions]The experimental method has simple operation and could achieve a good effect with wide linear range and correlation coefficient over 0. 999 8,and the obtained results are satisfactory.展开更多
In the present study, free fatty acids(FFAs, including palmitic acid, stearic acid, oleic acid, linoleic acid and arachidonic acid) in rabbit plasma were determined by gas chromatography-mass spectrometry(GC-MS) after...In the present study, free fatty acids(FFAs, including palmitic acid, stearic acid, oleic acid, linoleic acid and arachidonic acid) in rabbit plasma were determined by gas chromatography-mass spectrometry(GC-MS) after trimethylsilylation derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide(BSTFA) – trimethylchlorosilane(TMCS) as derivatization reagent. The experimental conditions, including extraction and silylation reaction, were investigated. The method was experimentally validated. The linearity between fatty acids’ peak areas and their concentrations was obtained with the corelative coefficient(r2) all more than 0.999, and the recoveries were between 82% and 111%. The intra-day variations of FFAs’ in plasma samples at different concentrations were all less than 6%. FFA analysis results of 16 rabbit plasma samples showed that the method could be well applied in the determination of plasma samples in vivo. In contrast to the traditional method of FFA derivatization, the established trimethylsilylation method presented simplicity, high specificity, and completely free from the interference of the esterified fatty acid, such as triacylglyceride. The method could be applied for analyzing FFA profiles in the clinical laboratory or pharmacological research.展开更多
A new HPLC method has been developed for determining donepezil in human plasma. To find the optimum conditions, a derivatization reaction was performed in different media, and the reaction product was identified by NM...A new HPLC method has been developed for determining donepezil in human plasma. To find the optimum conditions, a derivatization reaction was performed in different media, and the reaction product was identified by NMR and GC-MS after a semi-preparative HPLC separation. Under optimized conditions, donepezil was derivatized by 9-fluorenylmethyl chloroformate in chloroform and carbonate buffer at pH 9.5 in the presence of NaI after solid-phase extraction from a plasma sample. The reaction product was quantified on a reversed-phase TRACER EXCEL ODS-A, 5 μm column using a mixture of acetonitrile–10 mM acetate buffer(pH 6.0)–THF(60:35:5, v/v/v) as the mobile phase with fluorescence detection at 264 nm(ex) and 313 nm(em). Fluoxetine was used as the internal standard. The total run-time of the analysis was about 10 min, and a clean chromatogram was obtained. The developed method was linear over the range of 1–100 ng/mL in 500 μL of plasma samples(r2>0.998). The intra-day and inter-day precision values were in the range of 2.6%–11.6%. The limit of quantification was 1 ng/mL.展开更多
This paper reviews studies on dissolution, derivatization, and nanomaterial processing of chitin using an ionic liquid as useful media. Because chitin is the second most abundant polysaccharide on the earth after cell...This paper reviews studies on dissolution, derivatization, and nanomaterial processing of chitin using an ionic liquid as useful media. Because chitin is the second most abundant polysaccharide on the earth after cellulose, there is major interest in conversion of native chitin resources into various useful materials after proper dissolution in suitable solvents. For the derivatization and nanomaterial processing of chitin, the author has been focusing on ionic liquids because which have been found to be used as good solvents for cellulose in a past decade. The author found that an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), dissolved chitin in concentrations up to 4.8 wt% and mixtures of the higher amounts of chitin with AMIMBr gave ion gels. Acetylation, the simplest derivatization, of chitin using acetic anhydride was achieved in the AMIMBr solvent under mild conditions. Furthermore, the chitin nanofibers were fabricated by regeneration technique from the chitin ion gel with AMIMBr using methanol. Moreover, filtration of the chitin nanofiber dispersion with methanol was carried out to give a chitin nanofiber film. The chitin nanofiber-poly(vinyl alcohol) composite film was also prepared from the ion gel by co-regeneration method.展开更多
A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were...A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were minced and mixed,and extracted with ultra pure water at 90℃ for 20 min. The 6-aminoquinolyl N-hydroxy-succinimidyl carbamate( AQC) was used as pre-column derivatization reagent. Gradient HPLC separation was performed on a C_(18) column( Symmetry C_(18),3. 9 mm × 15 cm,4 μm). Good linearity between concentrations and peak areas was achieved in the concentration range of 5. 0-250 μmol/L for 18 kinds of amino acids. The method was validated by the analysis of five replicates. The 18 kinds of amino acid standards were spiked in fresh tea leaf samples and the average recovery rate was 86. 25%-109. 05% with relative standard deviations( n = 5) ranging from 6. 03% to 10. 56%. The limit of detection( LOD) for the analytes was0. 05-1. 27 μmol/L. The method was successfully applied to the analysis of the 18 kinds of amino acids in fresh tea leaves from east Dongting and west Dongting mountains in Suzhou. The results indicate that the method is simple,rapid,precise and reliable.展开更多
Three main phytotoxic compounds including lunatoic acid A （1）, 5Z-7-oxozeaenol （2） and zeaenol （3） were isolated from the fermentation broth of Cladosporium oxysporum DH14, a fungus residing in the locust （Oxya...Three main phytotoxic compounds including lunatoic acid A （1）, 5Z-7-oxozeaenol （2） and zeaenol （3） were isolated from the fermentation broth of Cladosporium oxysporum DH14, a fungus residing in the locust （Oxya chinensis ） gut. Two additional derivative compounds, compound la and lb, were synthesized by methylation and chlorination of compound 1, respectively. The structures of such compounds were identified on the basis of spectroscopic analysis and by comparison of the corresponding data to those previously reported in the literature. Compounds 1-3 exhibited significantly phytotoxic activities against the radicle growth of Amaranthus retroflexus L. with the 50% inhibitory concentrations （ICso values） of 4.51, 4.80 and 8.16 μg· mL^-1, respectively, which is comparable to that positive control 2,4-dichlorophenoxyacetic acid （IC50=1.95 μg· mL^-1）. Furthermore, the compound 1 showed selective phytotoxic activity with the inhibition rate of less than 22% against the crops of Brassica rapa L., Sorghum durra, Brassica campestris L,, Capsicum annucm and Raphanus safivus L. under the concentration of 100 μg· mL^-1 Both derivatives of compound 1 had moderate phytotoxic activity against the radicle growth of A. retroflexus L. The findings of our present study suggest that these compounds provide new promising candidates for the potential management strategies of weeds.展开更多
In this work,a new pyrylium derivatization-assisted liquid chromatography-mass spectrometry(LC-MS)method was developed for metabolite profiling of the glutathione anabolic pathway(GAP)in cancer tissues and cells.The p...In this work,a new pyrylium derivatization-assisted liquid chromatography-mass spectrometry(LC-MS)method was developed for metabolite profiling of the glutathione anabolic pathway(GAP)in cancer tissues and cells.The pyrylium salt of 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate(DMMIC)was used to label the amino group of metabolites,and a reductant of dithiothreitol(DTT)was employed to stabilize the thiol group.By combining DMMIC derivatization with LC-MS,it was feasible to quantify the 13 main metabolites on the GAP in complex biological samples,which had good linearity(R^(2)=0.99810.9999),precision(interday precision of 1.6%e19.0%and intraday precision of 1.4%e19.8%)and accuracy(83.4%-115.7%).Moreover,the recovery assessments in tissues(82.5%e107.3%)and in cells(98.1%e118.9%)with GSH-^(13)C2,^(15)N,and Cys-^(15)N demonstrated the reliability of the method in detecting tissues and cells.Following a methodological evaluation,the method was applied successfully to investigate difference in the GAP between the carcinoma and para-carcinoma tissues of esophageal squamous cell carcinoma(ESCC)and the effect of p-hydroxycinnamaldehyde(CMSP)on the GAP in KYSE150 esophageal cancer cells.The results demonstrate that the developed method provides a promising new tool to elucidate the roles of GAP in physiological and pathological processes,which can contribute to research on drugs and diseases.展开更多
基金supported by the National Natural Science Foundation of China(Nos.82374028 and 81803957)。
文摘Matrix-assisted laser desorption/ionization(MALDI)mass spectrometry imaging(MSI)is an attractive technology for the visualization of metabolite distributions in tissues.However,detection and identification of low-abundance or poorly ionized metabolites remains challenging.Although on-tissue chemical derivatization(OTCD)holds great promise for improving MALDI MS detection sensitivity and selectivity by modification of specific chemical groups,the available methods for subsequent metabolite annotation are limited.Herein,a laser-assisted chemical transfer(LACT)-based parallel OTCD strategy was established for visualizing and annotating carbonyl metabolites in murine brain tissues.Girard's T and Girard's P reagents were applied for parallel OTCD to generate the characteristic m/z pairs with a 19.969 Da mass shift(±0.020 Da tolerance)for rapid recognition of derivatized metabolites.The similarity of spatial distribution patterns of each m/z pair was further statistically evaluated to remove the ambiguous annotations due to the occurrence of interference compounds.As a result,90 ion pairs were annotated as candidate carbonyl metabolites,66 were previously known and 24 were potential unreported carbonyls.Furthermore,the spatial alterations of carbonyl metabolites in the ischemic rat brain were successfully visualized and characterized,including small molecule aldehydes and ketones,long-chain fatty aldehydes,and monosaccharides.This further emphasizes great potential of parallel OTCD strategy for efficient and confident molecular annotation of spatial submetabolomics data associated with brain diseases.
基金Supported by National Key Technologies R & D Program(2007BAD58B03)~~
文摘[Objective] This study aimed to establish a pre-column derivatization HPLC method for the identification and analysis of monosaccharide composition of Pu-erh tea polysaccharide. [Method] Pu-erh tea polysaccharide was extracted using the wa- ter extraction method, further isolated and purified by DEAE cellulose-52 columns. The obtained tea polysaccharide and four components TPS1, TPS2, TPS3 and TPS, were first derived by 1-phenyl-3-methyl-5-pyrazolone （PMP）, and then the PMP derivatives of monosaccharide were analyzed by high performance liquid chromatog- raphy （HPLC）. [Result] Pu-erh tea polysaccharide contained eight kinds of monosac- chaddes （mannose, rhamnose, glucuronic acid, galacturonic acid, grucose, galactose, arabinose, fucose）, without xylose; so it was the same with TPS1; each of TPS2, TPS3 and TPS4 contained seven monosaccharides, while no fucose. [Conclusion] This method is simplified and rapid, which can be used to determine the monosac- charide composition of Pu-erh tea polysaccharide and monosaccharide content.
文摘Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extracted from the dog serum using dichlromethane followed by derivatization with DNBF for 20 min at 100℃. The solvent was then evaporated at 60℃ under nitrogen, and the residue was taken up in 100 μL of mobile phase consisting of acetonitrile water (75∶30, v/v). The separation was performed on a Hypersil BDS C18 column with a flow rate of 0 8 mL·min -1 , and the ultraviolet detector wavelength was set at 350 nm. Results Extraction recovery ranged from 75.9% to 83.2%, and methodological recovery was between 96.5% and 109.3%. Within day RSD ranged from 1.5% to 6.3%, and inter day RSD was between 2 9% and 14.8%. The method showed good linearity (R=0.9998). Conclusion The method was simple, convenient and sensitive. The reaction of derivatization was reproducible.
文摘A pre-column derivatization HPLC method for the determination of peimine(P)and peiminine(PE)in Bulbus Fritillariae has been developed. Under the derivatization conditions optimized,the calibration curve is Y1=-3.83×103+1.33 ×105X1,r=0.998 for P and Y2=-7.86 × 102+6.33 × 104X2,r=0995 for PE,where Y is the peak area and X is the weight of the alkaloid; the average recovery is 98.0%(n=5, RSD=2.1%) for P and 101.0%(n=5,RSD=4.1%)for PE,the linear range is from 0.504 μg to 3.126μg for P and from 0.520μgto 3.328μgfor PE,respectively. Results of the determination of the two alkaloids in several samples of different Fritillaria species from various parts ofthe country are presented.The results suggest that P and PE are two major chemical constituents in bulbs of different Fritillaria species,and that the method developed is generally appli-cable to the determination of the hydroxy group on aliphatic fused ring systems without steric hin-drance.
基金supported by the National Basic Research Program of China (973 Program, Grant No. 2010CB428901)the National Natural Science Foundation of China (NSFC, Grant No. 41020164005,41276067)the team of 973 Program Grant No. 2010CB428701 for the help during sampling
文摘Lignin serves as one of the most important molecular fossils for tracing Terrestrial Organic Matters （TOMs） in marine environment. Extraction and derivatization of lignin oxidation products （LOPs） are crucial for accurate quantification of lignin in marine sediment. Here we report a modification of the conventional alkaline cupric oxide （CuO） oxidation method, the modification consisting in a solid phase extraction （SPE） and a novel on-column derivatization being employed for better efficiency and reproducibility. In spiking blanks, recoveries with SPE for the LOPs are between 77.84% and 99.57% with relative standard deviations （RSDs） ranging from 0.57% to 8.04% （n=3）, while those with traditional liquid-liquid extraction （LLE） are from 44.52% to 86.16% With RSDs being from 0.53% to 13.14% （n=3）. Moreover, the reproducibility is greatly improved with SPE, with less solvent consumption and shorter processing time. The average efficiency of on-column derivatization for LOPs is 100.8%±0.68%, which is significantly higher than those of in-vial or in-syringe derivatization, thus resulting in still less consumption of derivatizing reagents.Lignin in the surface sediments sampled from the south of Yangtze River estuary, China, was determined with the established method. Recoveries of 72.66% to 85.99% with standard deviation less than 0.01mg/10g dry weight are obtained except for p-hydroxybenzaldehyde. The lignin content ∑8 （produced from 10g dry sediment） in the research area is between 0.231 and 0.587mg. S/V and C/V ratios （1.028 ± 0.433 and 0.192±0.066, respectively） indicate that the TOMs in this region are originated from a mixture of woody and nonwoody angiosperm plants; the high values or （Ad/Al）v suggest that the TOMs has been highly degraded.
基金National Key Project of China(Grant No. 2009ZX09304-003).
文摘A reversed-phase high-performance liquid chromatographic （RP-HPLC） method was established for the determination of the enantiomers of 7 aryloxy aminopropanol drugs （atenolol, sotalol, celiprolol, carvedilol, metoprolol, propranolol and propafenone） in transport medium. The method involved liquid-liquid extraction of chiral drugs from transport medium, and employed 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate （GITC, 1.0 mg/mL in acetonitrile） as a pre-column chiral derivatization reagent. After derivatization, the products were separated on an Agilent Zorbax C8 column （150 min×4.6 mm, 5 μm） at 25 ℃. The mobile phase consisted of a mixture of acetonitrile and 0.01 M phosphate buffer （pH 3.5）. The present methods were specific for the determination of enantiomers of each chiral drug. The absolute recoveries of the enantiomers and internal standards were 〉78%. The relative recoveries of the enantiomers were approximately 100%. The intra- and inter-day variations were 〈 15%. The method was reproducible and sufficiently sensitive to determine the enantiomers of seven aryloxy aminopropanol drugs in transport medium. The method could be used to study the transport of atenolol, sotalol, celiprolol, carvedilol, metoprolol, propranolol and propafenone.
基金supported by the National Key R&D Program of China(No.2018YFA0900400)the National Natural ScienceFoundation of China(Nos.21635006,31670373,21721005,21904099)the Postdoctoral Science Foundation of China(No.2018M642893)。
文摘Direct infusion mass spectrometry(DIMS) is a powerful technique in clinical diagnosis for screening neonatal amino acid metabolic disorders from dried blood spots(DBS).However,DIMS sometimes generated false-positive results for analysis of amino acids.In this work,we utilized a stable isotope derivatization method,combining with liquid chromatography tandem mass spectrometry(SID-LC-MS),to improve the specificity for screening amino acids in DBS specimens.A pair of isotope reagents,p-(dimethylamino)phenyl isothiocyanate(DMAP-NCS) and 4-isothiocyanato-N,N-bis(methyl-[2H2])aniline([2H4]DMAP-NCS),was synthesized and used to label amino acids in DBS specimens.The [2H4]DMAP-NCS labelled amino acid standards were used as internal standards to compensate the matrix effect.This method was validated by measuring linearity,recovery and accuracy.The results showed that the developed SID-LC-MS method can be used for sensitive and selective determination of 12 diagnostically important amino acids in DBS specimens.
基金supported by the National Natural Science Foundation of China(No.21927808)the Chinese Academy of Medical Science(CAMS)Innovation Fund for Medical Sciences(CIFMS,Nos.2022-I2M-2-002 and 2021-1-I2M-028).
文摘On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI).Combination OTCD and MSI provides a novel strategy for visualizing previously undisclosed metabolic heterogeneity in tumor.Herein,we present a method to visualize heterogeneous metabolism of oxylipins within tumor by coupling OTCD with airflow-assisted desorption electrospray ionization(AFADESI)-MSI.Taking Girard’s P as a derivatization reagent,easily ionized hydrazide and quaternary amine groups were introduced into the structure of carbonyl metabolites via condensation reaction.Oxylipins,including 127 fatty aldehydes(FALs)and 71 oxo fatty acids(FAs),were detected and imaged in esophageal cancer xenograft with AFADESI-MSI after OTCD.Then t-distributed stochastic neighbor embedding and random forest were exploited to precisely locate the distribution of oxylipins in heterogeneous tumor tissue.With this method,we surprisingly found almost all FALs and oxo FAs significantly accumulated in the core region of tumor,and exhibited a gradual increase trend in tumor over time.These results reveal spatiotemporal heterogeneity of oxylipins in tumor progression,highlighting the value of OTCD combined with MSI to gain deeper insights into understanding tumor metabolism.
文摘A selective precolumn derivatization liquid chromatography–tandem mass spectrometric (LC–MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was derivatized by o-phthalaldehyde/3-mercaptopropionic acid. Chromatographic separation was performed on a Phenomenex ODS column (150 mm 4.6 mm, 5 mm) using linear gradient elution by a mobile phase consisting of methanol (A), and an aqueous solution containing 0.2% ammonium acetate and 0.1% formic acid (B) at a flow rate of 1 mL/min. Tolterodine tartrate was used as the internal standard (IS). With protein precipitation by acetonitrile and then the simple one-step derivatization, a sensitive bio-assay was achieved with the lower limit of quantitation (LLOQ) as low as 12 ng/mL for plasma. The standard addition calibration curves suitable for clinical sample analysis showed good linearity over the range of 0.012–8.27 mg/mL in plasma and 1.80–84.1 mg/mL in urine. The fully validated method has been successfully applied to a pharmacokinetic study of compound glucosamine sulfate dispersible tablets in health Chinese volunteers receiving single oral doses at 500, 1000 and 1500 mg of glucosamine sulfate, as well as multiple oral doses of 500 mg t.i.d. for 7 consecutive days.
基金supported by the National Key R&D Program of China (No. 2017YFC0906800)the National Natural Science Foundation of China (Nos. 21522507, 21672166, 21635006 and 21721005)
文摘Now increasing chemical modifications are discovered on genomic DNA and RNA. Up to date, more than150 chemical modifications are identified in nucleic acids. These chemical modifications do not change the sequence of DNA and RNA, but alter their structures and biochemical properties, and eventually control or regulate the spatial and temporal expression of genes. Elucidation of the functional roles of these modifications is vital to our understanding of living organisms. However, the modifications in DNA and RNA generally have extremely low abundance in vivo. Therefore, sensitive and specific detection methods are essential to decipher the functional roles of these modifications. Chemical derivatization in combination with mass spectrometry(MS) analysis has been proved to be a promising strategy to efficiently analyze these modifications in DNA and RNA. In the last several years, many chemical derivatization-MS-based analytical methods were established for the sensitive and effective analysis of nucleic acid modifications. In this review, we summarize the recent advances for deciphering modifications in DNA and RNA by chemical derivatization-MS analysis. We hope this review can stimulate the future studies of DNA and RNA modifications.
基金Project supported by the National Natural Science Foundation of China (No. 30225047) and by SRF for ROCS+2 种基金 SEM and Zhejiang Provincial Natural Science Foundation (No. RC97016) China
文摘The enantioselective assay for S(+)- and R(-)-propafenone (PPF) in human urine that developed in this work involves extraction of propafenone from human urine and using S(+)-propafenone as internal standard, chiral derivatization with 2,3,4,6-tetra-O-b-D-glucopranosyl isothiocyanate, and quantitation by an RP-HPLC system with UV detection (l=220 nm). A baseline separation of propafenone enantiomers was achieved on a 5-mm reverse phase ODS column, with a mixture of methanol:water:glacial acetic acid (25:12:0.02,v/v) as mobile phase. There was good linear relationship from 24.9 ng/ml to 1875.0 ng/ml for both of enantiomers. The regression equations of the standard curves based on CS-PPF (or CR-PPF ) versus ratio of AS-PPF/AS (or AR-PPF/AS ) were y=0.0032x-0.081, (r=0.999) for S-PPF and y=0.0033x+0.0039, (r=0.998) for R-PPF, respectively. The method抯 limit of detection was 12.5 ng/ml for both enantiomers, and the method抯 limit of quantitation was 28.20.52 ng/ml for S-PPF, 30.40.53 ng/ml for R-PPF (RSD<8%, n=5). The analytical method yielded average recovery of 98.9% and 100.4% for S-PPF and R-PPF, respectively. The relative standard deviation was no more than 6.11% and 6.22% for S-PPF and R-PPF, respectively. The method enabled study of metabolism of S(+)- and R(-)-propafenone in human urine. The results from 7 volunteers administered 150 mg racemic propafenone indicated that propafenone enantiomers undergo stereoselective metabolism and that in the human body, S(+)-propafenone is metabolized more extensively than R(-)- propafenone.
基金supported by the National Key R&D Program of China(Nos.2022YFA0806600,2022YFC3400700)the National Natural Science Foundation of China(Nos.22277093,22074110,21721005).
文摘Inosine is a vital RNA modification across three kingdoms of life.It has been demonstrated that inosine plays important roles in modulation of the fate of RNAs.In the current study,we developed a highly sensitive method to determine inosine in a single cell by N-cyclohexyl-N’-β-(4-methylmorpholinium)ethylcarbodiimide p-toluenesulfonate(CMCT)derivatization in combination with mass spectrometry analysis.The results showed that the detection sensitivity of inosine was increased by 556-fold after CMCT derivatization,with the limit of detection(LOD)being 4.5 amol.With the established method,we could detect inosine from 13.0 pg of total RNA of HEK293T cells.Meanwhile,inosine in RNA from a single cell could also be clearly detected due to the improved detection sensitivity.Moreover,we found the level of inosine in RNA of sleep-deprived mice was significantly increased compared to the control mice,indicating that inosine is associated with sleep behavior and might be a potential indicator of sleep disorder.Taken together,the chemical derivatization coupled with mass spectrometry analysis offers a valuable tool in determination of endogenous RNA modifications in a single cell,which should benefit the functional study of RNA modification in rare clinical samples.
基金National Natural Science Foundation of China(Grant No.21275167)the Natural Science Foundation of Hubei Province(Grant No.2014CFA025)the Preferred Research Foundation for the Returned Overseas Scholars from Ministry of Human Resources and Social Security of the People’s Republic of China for financial support.
文摘A sensitive and rapid high performance liquid chromatography-mass spectrometry(HPLC-MS)method was developed and validated for simultaneous quantifcation of ten steroid hormones,including estrogens,androgens,progesterones,and corticosteroids four classes of steroids.The following ten steroid hormones were analyzed:progesterone,21-deoxycortisol,estrone,4-androstenedione,testosterone,dihydro-testosterone,androstenone,dehydroepiandrosterone,corticosterone and cortisone.Stable deuterated isotopes were used as internal standards for quantifcation.Sample preparation with and without derivatization were performed after liquid-liquid extraction,and the corresponding results were compared according to sensitivity and selectivity.Hydroxylamine derivatization was found to improve the ionization efciency of the analytes for electrospray ionization MS analysis.The gradient of mobile phase and experimental parameters for HPLC separation were optimized.The lower limits of quantifcation were in the range of 0.05-5 ng mL^(−1) with wide linear range for the ten steroid hormones.The intra-day precision<11.1%and recovery of 84.5-120% with negligible matrix efect were achieved,where within the acceptance limits of the FDA guideline.Total HPLC-MS analysis time was 6 min.This method enables simultaneous quantifcation of steroids in human serum.It will be helpful for the serum steroid profling in order to understand various endocrinology diseases.
基金Supported by National Natural Science Foundation of Hainan Province(217157)Fund for Construction of Hainan Provincial Key Discipline(Thalassochemistry) in 2017
文摘[Objectives] This study was conducted to optimize the determination conditions of amino acids from abalone. [Methods] The sample was treated by acid hydrolysis method and subjected to 2,4-2 nitro fluorobenzene column derivatization. The amino acid content in abalone was determined by HLPC,and the nutritional value of the amino acids was evaluated with egg protein model put forward by Institute of Nutrition and Food Hygiene,Chinese Academy of Preventive Medicine. [Results] Abalone contains full amino acids. According to the FAO/WHO ideal,it is a high-quality protein source and suitable for supplement of protein source for human body. [Conclusions]The experimental method has simple operation and could achieve a good effect with wide linear range and correlation coefficient over 0. 999 8,and the obtained results are satisfactory.
基金National Natural Science Foundation of China (Grant No. 31671928)Natural Science Foundation of Shanghai (Grant No. 15ZR1440800)。
文摘In the present study, free fatty acids(FFAs, including palmitic acid, stearic acid, oleic acid, linoleic acid and arachidonic acid) in rabbit plasma were determined by gas chromatography-mass spectrometry(GC-MS) after trimethylsilylation derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide(BSTFA) – trimethylchlorosilane(TMCS) as derivatization reagent. The experimental conditions, including extraction and silylation reaction, were investigated. The method was experimentally validated. The linearity between fatty acids’ peak areas and their concentrations was obtained with the corelative coefficient(r2) all more than 0.999, and the recoveries were between 82% and 111%. The intra-day variations of FFAs’ in plasma samples at different concentrations were all less than 6%. FFA analysis results of 16 rabbit plasma samples showed that the method could be well applied in the determination of plasma samples in vivo. In contrast to the traditional method of FFA derivatization, the established trimethylsilylation method presented simplicity, high specificity, and completely free from the interference of the esterified fatty acid, such as triacylglyceride. The method could be applied for analyzing FFA profiles in the clinical laboratory or pharmacological research.
文摘A new HPLC method has been developed for determining donepezil in human plasma. To find the optimum conditions, a derivatization reaction was performed in different media, and the reaction product was identified by NMR and GC-MS after a semi-preparative HPLC separation. Under optimized conditions, donepezil was derivatized by 9-fluorenylmethyl chloroformate in chloroform and carbonate buffer at pH 9.5 in the presence of NaI after solid-phase extraction from a plasma sample. The reaction product was quantified on a reversed-phase TRACER EXCEL ODS-A, 5 μm column using a mixture of acetonitrile–10 mM acetate buffer(pH 6.0)–THF(60:35:5, v/v/v) as the mobile phase with fluorescence detection at 264 nm(ex) and 313 nm(em). Fluoxetine was used as the internal standard. The total run-time of the analysis was about 10 min, and a clean chromatogram was obtained. The developed method was linear over the range of 1–100 ng/mL in 500 μL of plasma samples(r2>0.998). The intra-day and inter-day precision values were in the range of 2.6%–11.6%. The limit of quantification was 1 ng/mL.
文摘This paper reviews studies on dissolution, derivatization, and nanomaterial processing of chitin using an ionic liquid as useful media. Because chitin is the second most abundant polysaccharide on the earth after cellulose, there is major interest in conversion of native chitin resources into various useful materials after proper dissolution in suitable solvents. For the derivatization and nanomaterial processing of chitin, the author has been focusing on ionic liquids because which have been found to be used as good solvents for cellulose in a past decade. The author found that an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), dissolved chitin in concentrations up to 4.8 wt% and mixtures of the higher amounts of chitin with AMIMBr gave ion gels. Acetylation, the simplest derivatization, of chitin using acetic anhydride was achieved in the AMIMBr solvent under mild conditions. Furthermore, the chitin nanofibers were fabricated by regeneration technique from the chitin ion gel with AMIMBr using methanol. Moreover, filtration of the chitin nanofiber dispersion with methanol was carried out to give a chitin nanofiber film. The chitin nanofiber-poly(vinyl alcohol) composite film was also prepared from the ion gel by co-regeneration method.
基金Supported by Open Project of the Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base(201603)Basic Research Project of Application of Suzhou City(SNG201622)
文摘A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were minced and mixed,and extracted with ultra pure water at 90℃ for 20 min. The 6-aminoquinolyl N-hydroxy-succinimidyl carbamate( AQC) was used as pre-column derivatization reagent. Gradient HPLC separation was performed on a C_(18) column( Symmetry C_(18),3. 9 mm × 15 cm,4 μm). Good linearity between concentrations and peak areas was achieved in the concentration range of 5. 0-250 μmol/L for 18 kinds of amino acids. The method was validated by the analysis of five replicates. The 18 kinds of amino acid standards were spiked in fresh tea leaf samples and the average recovery rate was 86. 25%-109. 05% with relative standard deviations( n = 5) ranging from 6. 03% to 10. 56%. The limit of detection( LOD) for the analytes was0. 05-1. 27 μmol/L. The method was successfully applied to the analysis of the 18 kinds of amino acids in fresh tea leaves from east Dongting and west Dongting mountains in Suzhou. The results indicate that the method is simple,rapid,precise and reliable.
基金the National Natural Science Foundation of China (NSFC) (21002092 and 21272215)the Open Project of State Key Laboratory of Pharmaceutical Biotechnology in Nanjing University, China (KF-GN-201411)
文摘Three main phytotoxic compounds including lunatoic acid A （1）, 5Z-7-oxozeaenol （2） and zeaenol （3） were isolated from the fermentation broth of Cladosporium oxysporum DH14, a fungus residing in the locust （Oxya chinensis ） gut. Two additional derivative compounds, compound la and lb, were synthesized by methylation and chlorination of compound 1, respectively. The structures of such compounds were identified on the basis of spectroscopic analysis and by comparison of the corresponding data to those previously reported in the literature. Compounds 1-3 exhibited significantly phytotoxic activities against the radicle growth of Amaranthus retroflexus L. with the 50% inhibitory concentrations （ICso values） of 4.51, 4.80 and 8.16 μg· mL^-1, respectively, which is comparable to that positive control 2,4-dichlorophenoxyacetic acid （IC50=1.95 μg· mL^-1）. Furthermore, the compound 1 showed selective phytotoxic activity with the inhibition rate of less than 22% against the crops of Brassica rapa L., Sorghum durra, Brassica campestris L,, Capsicum annucm and Raphanus safivus L. under the concentration of 100 μg· mL^-1 Both derivatives of compound 1 had moderate phytotoxic activity against the radicle growth of A. retroflexus L. The findings of our present study suggest that these compounds provide new promising candidates for the potential management strategies of weeds.
基金We thank the Shanghai Municipal Committee of Science and Technology(Grant Nos.:20XD1423400,23ZR1460900 and 20DZ2201100)Shanghai Municipal Health Commission/Shanghai Municipal Administration of Traditional Chinese Medicine(Grant No.:ZY(2021e2023)-0501)+2 种基金Shanghai Science and Technology Development Fund from Central Leading Local Government(Grant No.:YDZX20223100001004)National Natural Science Foundation of China(Grant No.:21672249)Expenditure Budget Program of Shanghai University of Traditional Chinese Medicine(Grant Nos.:2020LK051,and 2021LK001).
文摘In this work,a new pyrylium derivatization-assisted liquid chromatography-mass spectrometry(LC-MS)method was developed for metabolite profiling of the glutathione anabolic pathway(GAP)in cancer tissues and cells.The pyrylium salt of 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate(DMMIC)was used to label the amino group of metabolites,and a reductant of dithiothreitol(DTT)was employed to stabilize the thiol group.By combining DMMIC derivatization with LC-MS,it was feasible to quantify the 13 main metabolites on the GAP in complex biological samples,which had good linearity(R^(2)=0.99810.9999),precision(interday precision of 1.6%e19.0%and intraday precision of 1.4%e19.8%)and accuracy(83.4%-115.7%).Moreover,the recovery assessments in tissues(82.5%e107.3%)and in cells(98.1%e118.9%)with GSH-^(13)C2,^(15)N,and Cys-^(15)N demonstrated the reliability of the method in detecting tissues and cells.Following a methodological evaluation,the method was applied successfully to investigate difference in the GAP between the carcinoma and para-carcinoma tissues of esophageal squamous cell carcinoma(ESCC)and the effect of p-hydroxycinnamaldehyde(CMSP)on the GAP in KYSE150 esophageal cancer cells.The results demonstrate that the developed method provides a promising new tool to elucidate the roles of GAP in physiological and pathological processes,which can contribute to research on drugs and diseases.
