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Current Perspectives and Methods for the Characterization of Natural Medicines
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Muthusamy Ramesh, Arunachalam Muthuraman, Nallapilai Paramakrishnan, Balasubramanyam I. Vishwanathan
Liquid chromatography-mass spectrometry (LC-MS) identifies the drug metabolites of polar to non-polar. LC-MS separates metabolites based on polarity, molecular weight, and hydrophobicity. Two different types of basic principles were employed in LC, i.e., (i) normal liquid phase chromatography where the polar stable phase is employed; and (ii) reverse-phase liquid chromatography where non-polar stable phase is employed. Mass spec-trometry serves as a detector to identify the metabolites. Molina-Calle et al. demonstrated the characterization of Stevia leaves constituents by LC with quadrupole—a time of flight (LC-QTOF) mass spectrometry (Molina-Calle et al., 2017). Mediterranea Sea (C18) column has 5 μ m, 15 × 0.46 cm dimension and it is used in LC-MS device. The source of electrospray ionization was used in mass spectrometry. Steviol and its glycosides were determined from the analysis of polar and non-polar components of Stevia leaves. A total of eighty-one compounds of different chemical classes of flavonoids, quinic acids, caffeic acids, diterpenoids, sesquiterpenoids, amino acids, fatty acids, oligosaccharides, glycerolipids, fatty amides purines, and retinoids were identified. The study was proven to benefit the production of commercial products from Stevia (Steviarebaudiana bertoni) leaves (Molina-Calle et al., 2017). The LC-MS spectroscopy-based characterized phytoconstituents and marine compounds are listed in Table 2.2.
Chemical Structure of Lipid A: Recent Advances in Structural Analysis of Biologically Active Molecules
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
Ulrich Zähringer, Buko Lindner, Ernst T. Rietschel
Electrospray Ionization Mass Spectrometry Electrospray ionization mass spectrometry (ESI-MS) has proven to be a “very soft” and sensitive ionization method, where the surrounding liquid of the droplets has a moderating effect on the internal and translational energies of desorbed multiple-charged ions. ESI-MS was first applied by Harrata et al. to lipid A of E. ag-glomerans, which is believed to be the causative agent of a pulmonary affliction of textile mill workers (95). These authors showed that the acidity of the phosphate group of crude, underivatized lipid A provides improved ionization efficiency in the negative ion mode yielding only intact molecular ions. In a similar way, Chan and Reinhold demonstrated that the molecular mass profiling by ESI-MS in combination with CID tandem mass spectrometry provides an effective and sensitive technique for clarifying acyl components and related structural details of monophosphoryl lipid A (96). ESI-MS seems to be an efficient analytical method when combined with a separation system such as capillary electrophoresis (CE) prior to mass analysis. This combination (CE-ESI-MS) has been successfully used for O-deacylated LPS of Moraxella catarrhalis(97). It has to be pointed out in this context that lipid A could not be separated and analyzed by this method due to its insolubility in aqueous buffer systems.
Emerging Biomedical Analysis
Published in Lawrence S. Chan, William C. Tang, Engineering-Medicine, 2019
Many variants of ESI have been developed in recent years. Ambient ionization is a family of techniques that was derived from ESI to enable rapid MS analysis at lower cost. Ambient ionization techniques generate ions under ambient conditions for subsequent MS analysis directly on the sample with minimum sample preparation (Cooks et al. 2006, Nyadong et al. 2007). Representative ambient ionization techniques are desorption electrospray ionization (DESI) and direct analysis in real time (DART). In the DESI technique, an electrospray of charged solvent droplets hits the sample surface and extracts analyte molecules to form secondary droplets (Fig. 2). The secondary droplets undergo a similar ionization process with ESI and eventually are delivered to the inlet of a mass spectrometer (Takats et al. 2004). In the DART methodology, an electrical potential is applied to a helium gas stream to generate metastable species. These excited-state gas molecules subsequently react with the analyte surface to form ions (Cody et al. 2005). Due to the simple and cost-effective experimental setup, DESI, DART and other ambient ionization techniques, such as paper spray ionization, liquid microjunction surface sampling probe (LMJ-SSP) and rapid evaporative ionization mass spectrometry (REIMS), were used in several clinical studies (Li et al. 2017). Examples of clinical applications of ambient ionization MS will be discussed later in this chapter.
Guilu-Erxian-Glue alleviates Tripterygium wilfordii polyglycoside-induced oligoasthenospermia in rats by resisting ferroptosis via the Keap1/Nrf2/GPX4 signaling pathway
Published in Pharmaceutical Biology, 2023
Jin Ding, Baowei Lu, Lumei Liu, Zixuan Zhong, Neng Wang, Bonan Li, Wen Sheng, Qinghu He
The chemical compounds in the alcohol extracts of GLEXG were characterized using an ACQUITY UPLC I-Class Plus UPLC system coupled with a XEVO TQ-XS Q/TOF-MS (Waters, USA) in positive and negative ion mode. Chromatography was performed on a Waters HSS T3 column (100.0 mm × 2.1 m, 1.7 μm) with a gradient elution of 0.1% formic acid aqueous solution (A) and acetonitrile (0–10 min, 0.2–20%; 10–20 min, 20–40%; 20–25 min, 40–50%; 25–33 min, 50–98%; 33 min, 50–98% (B). The mass spectrometry conditions were electrospray ionization with positive and negative ion mode scanning. For the negative ion mode, the ion source collision voltage was −4.5 kV, the ion source temperature was 100 °C, the dissolvent gas temperature was 550 °C, the sample and extraction cone voltages were 80 and 10 kV, respectively, and the ion source gas1 and gas2 were 55 Psi. For the positive ion mode, the ion source collision voltage was 5.5 kV, and the rest of the parameters were the same as in the negative ion mode. SCIEX OS (AB SCIEX, US) software was used for data acquisition and spectral processing, and the mass-to-charge ratio scan range was from 60 to 1000 m/z.
Metabolomics screening of serum biomarkers for occupational exposure of titanium dioxide nanoparticles
Published in Nanotoxicology, 2021
Zhangjian Chen, Shuo Han, Jiahe Zhang, Pai Zheng, Xiaodong Liu, Yuanyuan Zhang, Guang Jia
Untargeted metabolomics was detected by ultra-performance liquid chromatography time of flight mass spectrometry (Acquity UPLC I-Class-Xevo G2-XS, Waters, Milford, MA). The parameters of the chromatographic column (HSS T3 Acquity, C18, 2.1 × 100 mm, 1.7 µm) were as follows: the column temperature was 40 °C; the injector temperature was 4 °C; the injection volume was 2 μL; the mobile phase A was ultrapure water containing 0.1% formic acid; mobile phase B was acetonitrile containing 0.1% formic acid; the flow rate was 0.5 mL/min. The ionization of mass spectrometry was carried out by electrospray ionization (ESI). The results were measured by positive ion mode and negative ion mode, respectively. The acquisition mode was MSe, and the primary and secondary mass spectra were collected at the same time. The scanning range was 50–1200 Da. The parameters of mass spectrometry were as follows: ion source temperature was 130 °C; cone hole gas flow rate was 30 L/h; desolvent gas temperature was 400 °C; desolvent gas flow rate was 900 L/h; capillary voltage was 3.5 kV; cone hole voltage was 15 V.
Role of human flavin-containing monooxygenase (FMO) 5 in the metabolism of nabumetone: Baeyer–Villiger oxidation in the activation of the intermediate metabolite, 3-hydroxy nabumetone, to the active metabolite, 6-methoxy-2-naphthylacetic acid in vitro
Published in Xenobiotica, 2021
Kaori Matsumoto, Tetsuya Hasegawa, Kosuke Ohara, Tomoyo Kamei, Junichi Koyanagi, Masayuki Akimoto
Samples of the incubation mixtures of 3-OH-NAB were analyzed by comparisons with an authentic standard using LC-MS/MS for identification purposes. The HPLC system consisted of an LC-30AD system (Nexera X2 series, Shimadzu, Kyoto, Japan). An Inertsil ODS-3 column (2.1 × 150 mm, 5 µm, GL Sciences Inc., Tokyo, Japan) was used in the LC analysis. The separation of analytes was performed under gradient conditions at a flow rate of 0.2 mL/min. The mobile phase was prepared using 10 mM ammonium acetate solution (A) and acetonitrile (B); gradient mode, 25% B for the initial composition, 25–85% over 8 min, 85% B for 0.3 min, 85–25% over 0.2 min, and 25% B over 1.5 min. The column temperature was maintained at 40 °C and the injection volume was 10 µL. The total LC run time was 10.0 min. Mass spectrometric detection was performed on an LCMS-8060 system (Shimadzu Kyoto, Japan). Substances were ionised by electrospray ionization (ESI). Quantification was accomplished by multiple reaction monitoring (MRM) of the transition of m/z 215.4 (Q1) →156.3 (Q3) for 6-MNA.