• Natural Product Sciences
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• v.23 no.2
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• pp.84-91
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• 2017

This study proposes a sensitive and selective liquid chromatography-electrospray ionization tandem mass spectrometry method of efficiently assessing the quality of a traditional herbal medicine called Yeonggyechulgam-tang (YGCGT). The following compounds 1 - 11, namely, liquiritin apioside (1), liquiritin (2), liquiritigene (3), coumarin (4), cinnamic acid (5), cinnamaldehyde (6), glycyrrhizin (7), atractylenolide III (8), atractylenolide II (9), atractylenolide I (10), and pachymic acid (11) were separated on a UPLC BEH $C_{18}$ column ($2.1{\times}100mm$, $1.7{\mu}m$) at a column temperature of $45^{\circ}C$ eluted with a gradient condition of 0.1% (v/v) formic acid in distilled water and acetonitrile. The correlation coefficient of the calibration curve of the eleven constituents was ${\geq}0.9936$. The limits of detection and quantification of the compounds 1 - 11 were 0.06 - 4.73 ng/mL and 0.17-14.20 ng/mL, respectively. Using this analytical method, the compound 11 in lyophilized YGCGT decoction extract was not detected, while the compounds 1 - 10 were detected 0.13-166.43 mg/g.

• Natural Product Sciences
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• v.20 no.3
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• pp.182-190
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• 2014

An ultra-performance liquid chromatography (UPLC) coupled with electrospray ionization (ESI) tandem mass spectrometry (MS) method was established for quantitative analysis of twelve components, allantoin (1), morroniside (2), 5-hydroxymethyl-2-furfural (5-HMF) (3), loganin (4), coumarin (5), cinnamic acid (6), mesaconitine (7), cinnamaldehyde (8), hypaconitine (9), aconitine (10), alisol B (11), and alisol B acetate (12) in a Palmijihwang-hwan decoction. The twelve constituents were separated on a UPLC BEH C18 column ($2.1{\times}100mm$, $1.7{\mu}m$) at a column temperature of $40^{\circ}C$ by gradient elution with 0.1% (v/v) formic acid in water and acetonitrile as the mobile phase. The flow rate was 0.3 mL/min and the injection volume was $2.0{\mu}L$. Calibration curves of all compounds were acquired with values of the correlation coefficient ${\geq}0.99$ within the test ranges. The limits of detection and quantification for all analytes were 0.01 - 4.53 ng/mL and 0.03 - 13.60 ng/mL, respectively. The concentrations of the compounds 1 - 9 and 12 were 72.83, 4389.00, 4859.00, 3155.17, 223.67, 33.50, 1.97, 518.00, 2.25, and $25.00{\mu}g/g$, respectively. However, compounds 10 and 11 were not detected.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.901-905
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• 2004

A rapid, sensitive and selective hydrophilic interaction liquid chromatography-tandem mass spectrometric(HILIC-MS/MS) method for the determination of tiapride in human plasma was developed. Tiapride and internal standard, metoclopramide were extracted from human plasma with dichloromethane at basic pH and analyzed on an Atlantis HILIC silica column with the mobile phase of acetonitrile-ammonium formate (190 mM, pH 3.0) (94：6, v/v). The ana-Iytes were detected using an electrospray ionization tandem mass spectrometry in the multi-ple-reaction-monitoring mode. The standard curve was linear (r＝0.999) over the concentration range of 1.00-200 ng/mL. The coefficient of variation and relative error for intra- and inter-assay at three QC levels were 6.4∼8.8％ and -2.0∼3.6％, respectively. The recoveries of tiapride ranged from 96.3 to 97.4％, with that of metoclopramide (internal standard) being 94.2％. The lower limit of quantification for tiapride was 1.00 ng/mL using 1 00 $\mu$L of plasma sample.

• Mass Spectrometry Letters
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• v.9 no.4
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• pp.91-94
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• 2018

Bilin tetrapyrroles are metabolic products of the breakdown of porphyrins within a species. In the case of mammals, these bilins are formed by the catabolism of heme and can be utilized as either biomarkers in disease or as an indicator of human waste contamination. Although a small subset of bilin tandem mass spectrometry reports exist, limited data is available in online databases for their fragmentation. The use of fragmentation data is important for metabolomics analyses to determine the identity of compounds detected within a sample. Therefore, in this study, the fragmentation of bilins generated by positive ion mode electrospray ionization is examined by collision-induced dissociation (CID) as a function of collision energy on an FT-ICR MS. The use of the FT-ICR MS allows for high mass accuracy measurements, and thus the formulas of resultant product ions can be ascertained. Based on our observations, fragmentation behavior for hemin, biliverdin and its dimethyl ester, phycocyanobilin, bilirubin, bilirubin conjugate, mesobilirubin, urobilin, and stercobilin are discussed in the context of the molecular structure and collision energy. This report provides insight into the identification of structures within this class of molecules for untargeted analyses.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.177-183
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• 2022

The monomer and dimer structures of the amyloid fragment Aβ(1-16) sequence formed in H₂O were investigated using electrospray ionization mass spectrometry (MS) and tandem MS (MS/MS). Aβ16 monomers and dimers were indicated by signals representing multiple proton adduct forms, [monomer+zH]ⁿ⁺ (=M^z+, z = charge state) and [dimer+zH]^z+ (=D^z+), in the MS spectrum. Fragment ions of monomers and dimers were observed using collision-induced dissociation MS/MS. Peptide bond dissociation was mostly observed in the D1-D7 and V11-K16 regions of the MS/MS spectra for the monomer (or dimer), regardless of the monomer (or dimer) charge state. Both covalent and non-covalent bond dissociation processes were indicated by the MS/MS results for the dimers. During the non-covalent bond dissociation process, the D³⁺ dimer complex was separated into two components: the M¹⁺ and M²⁺ subunits. During the covalent bond dissociation of the D³⁺ dimer complex, the b and y fragment ions attached to the monomer, (M+b_10-15)^z+ and (M+y_9-15)^z+, were thought to originate from the dissociation of the M²⁺ monomer component of the (M¹⁺+M²⁺) complex. Two different D³⁺ complex geometries exist; two distinguished interaction geometries resulting from interactions between the M¹⁺ monomer and two different regions of M²⁺ (the N-terminus and C-terminus) are proposed. Intricate fragmentation patterns were observed in the MS/MS spectrum of the D⁵⁺ complex. The complicated nature of the MS/MS spectrum is attributable to the coexistence of two D⁵⁺ configurations, (M¹⁺+M⁴⁺) and (M²⁺M³⁺), in the Aβ16 solution.

• Mass Spectrometry Letters
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• v.8 no.4
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• pp.109-113
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• 2017

Single analytical procedure including extraction, liquid chromatography, and mass spectrometric analysis was evaluated for the simultaneous measurement of lysophospholipids (LPLs). LPLs, particularly, lysophosphatidic acids (LPA) and sphingosine 1-phosphate (S1P) are lipid messengers ubiquitously found in various biological matrix. The molecular species mediate important physiological roles in association with many diseases (e.g. cancer, inflammation, and neurodegenerative disease), which emphasize the significance of the simple and reliable analytical method for biomarker discovery and molecular mechanistic understanding. Thus, we developed analytical method mainly focusing on, but not limited by those lipid species S1P and LPA using reverse phase liquid chromatography-tandem mass spectrometry (RPLC-ESI-MS-MS). Extraction method was modified based on Folch method with optimally minimal level of ionization additive (ammonium formate 10 mM and formic acid). Reverse-phase liquid-chromatography was applied for chromatographical separation in combination with negative ionization mode electrospray-coupled Orbitrap mass spectrometry. The method validation was performed on human blood plasma in a non-targeted lipid profiling manner with full-scan MS mode and data-dependent MS/MS. The proposed method presented good inter-assay precision for primary targets, S1P and LPA. Subsequent analysis of other types of LPLs identified a broad range of lysophosphatidylcholines (LPCs) and lysophosphatidyl-ethanolamines (LPEs).

• Mass Spectrometry Letters
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• v.12 no.1
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• pp.21-25
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• 2021

We aimed to develop and validate a sensitive analytical method of nannozinone A, active metabolite of Nannochelins A extracted from the Myxobacterium Nannocytis pusilla, in mouse plasma using a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Mouse plasma samples containing nannozinone A and 13C-caffeine (internal standard) were extracted using a liquid-liquid extraction (LLE) method with methyl tert-butyl ether. Standard calibration curves were linear in the concentration range of 1 - 1000 ng/mL (r2 > 0.998) with the inter- and intra-day accuracy and precision results less than 15%. LLE method gave results in the high and reproducible extraction recovery in the range of 78.00-81.08% with limited matrix effect in the range of 70.56-96.49%. The pharmacokinetics of nannozinone A after intravenous injection (5 mg/kg) and oral administration (30 mg/kg) of nannozinone A were investigated using the validated LC-MS/MS analysis of nannozinone A. The absolute oral bioavailability of nannozinone A was 8.82%. Plasma concentration of nannozinone A after the intravenous injection sharply decreased for 4 h but plasma concentration of orally administered nannozinone A showed fast distribution and slow elimination for 24 h. In conclusion, we successfully applied this newly developed sensitive LC-MS/MS analytical method of nannozinone A to the pharmacokinetic evaluation of this compound. This method can be useful for further studies on the pharmacokinetic optimization and evaluating the druggability of nannozinone A including its efficacy and toxicity.

• Analytical Science and Technology
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• v.21 no.4
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• pp.245-258
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• 2008

Five triterpenic acids as marker compounds were extracted and isolated from Prunellae Spica by column chromatography and reversed-phase high-performance liquid chromatography (HPLC), and their purity was determinated by HPLC (purity ${\geq}90%$). Molecular weight and elemental compositions of the five marker compounds were determined by fast atom bombardment high-resolution mass spectrometry (FAB-HRMS). The structural determination of the five marker compounds was carried out fast atom bombardment collision-induced dissociation tandem mass spectrometry (FAB-CID-MS/MS). The collision-induced dissociation (CID) of protonated molecules $[M+H]^+$ and deprotonated molecules $[M-H]^-$ produced diverse product ions due mainly to retro Diels-Alder reaction (RDA), dehydration and decarboxylation. Moreover, the CID-MS/MS spectra of the $[M-H]^-$ ions were observed charge-remote fragmentation (CRF) patterns. On the basis of interpretation of CID-MS/MS spectra, structural elucidation of triterpenic acids isolated from Prunellae Spica was clearly performed.

• Mass Spectrometry Letters
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• v.6 no.4
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• pp.116-119
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• 2015

Globotriaosylsphingosine (lyso-Gb3) is considered as one of the biological marker for Fabry disease. To date, a reliable biomarker that reflects disease severity and progression has not been discovered to guide the management of Fabry disease. A new method included a simple protein precipitation with acetonitrile in 100 μL of plasma following analyte separation on an Phenomenex Kintex- C18 column using a gradient elution (0.1% formic acid in 5-90% acetonitrile). Total run time was within 12 min including sample preparation and MS/MS analysis. The limit of detection and limit of quantitation were 1 ng/mL and 2 ng/mL, respectively. The calibration curve was linear over the concentration range of 2.0-200.0 ng/mL (r² = 0.9999). Inter-day accuracy and precision at 7 level were 93.4-100.7% with RSD of 0.55-5.97%. Absolute recovery was 97.6-98.6%. The method was applied to human and mice plasma, proved the suitability for quantification of lyso-Gb3 for screening, diagnosis and therapeutic monitoring of Fabry disease patients.

• Preventive Nutrition and Food Science
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• v.6 no.4
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• pp.244-246
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• 2001

Angiotensin converting enzyme (ACE) inhibitor acts on the inhibition of ACE and causes a decrease in blood pressure. There have been several reports on screening of ACE inhibitors from natural food products and protein hydrolysates of various food sources. Ripe Cucurbita moschata Duch has been used as an oriental medicine in Korea. To isolate ACE inhibitors, crude water extracts of the edible portion of ripe Cucurbita moschata Duch were obtained after heating in water at 95$^{\circ}C$ for 2 h. Crude extracts were then filtered using PM-10 and YM-1 membranes. The membrane-filtered solution was loaded onto Sephadex G-15 column equlibrated with a phosphate buffer. Among the four major fractions of gel permeation chromatography, the second fraction had the highest inhibitory activity of 65%. Further purification of the fraction using reversed-phase HPLC with a $C_{18}$ column produced ACE inhibitors, which were identified as a mixture having molecular mass of 222 and 273 by Tandem mass spectrometry.