Development of HPLC/ESI-MS and HPLC/1H NMR Methods for the Identification of Photocatalytic Degradation Products of Iodosulfuron

2006 ◽  
Vol 78 (9) ◽  
pp. 2957-2966 ◽  
Author(s):  
Mohamad Sleiman ◽  
Corinne Ferronato ◽  
Bernard Fenet ◽  
Robert Baudot ◽  
Farouk Jaber ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
1H Nmr ◽  
Degradation Products ◽  
Esi Ms ◽  
Nmr Methods

Chemical analysis ofLithospermum canescens(Michx.) Lehm. Hairy roots through TLC, CC, GC-MS, ESI-MS, and NMR methods

2011 ◽  
Vol 23 (2) ◽  
pp. 353-363 ◽  
Author(s):  
K. Graikou ◽  
K. S. Baranek ◽  
A. Pietrosiuk ◽  
H. Damianakos ◽  
M. Jeziorek ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Hairy Roots ◽  
Esi Ms ◽  
Nmr Methods

scholarly journals Secondary metabolites of three endemic Centaurea L. species

2014 ◽  
Vol 79 (11) ◽  
pp. 1355-1362 ◽  
Author(s):  
Vele Tesevic ◽  
Ivana Aljancic ◽  
Slobodan Milosavljevic ◽  
Vlatka Vajs ◽  
Iris Djordjevic ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Nmr Spectroscopy ◽  
Secondary Metabolites ◽  
Sesquiterpene Lactone ◽  
1H Nmr ◽  
13C Nmr ◽  
1H Nmr Spectroscopy ◽  
13C Nmr Spectroscopy ◽  
Esi Ms ◽  
Aerial Parts

The aerial parts of three endemic Centaurea L. species, namely C. tomorosii Micevski, C. soskae Hayek and C. galicicae Micevski, afforded sesquiterpene lactone cnicin (1) and seven flavonoids: apigenin (2), isokaempferide (3), hispidulin (4), eupatorin (5), cirsimaritin (6), santaflavone (7) and salvigenin (8). The structures of the isolated compounds were determined by UV, 1H NMR and 13C NMR spectroscopy and HR-ESI-MS spectrometry. 1H NMR spectroscopy was used as a method for quantitative analysis of sesquiterpene lactone cnicin.

scholarly journals Isolation and Structure Determination of Echinochrome A Oxidative Degradation Products

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4778
Author(s):  
Natalia P. Mishchenko ◽  
Elena A. Vasileva ◽  
Andrey V. Gerasimenko ◽  
Valeriya P. Grigorchuk ◽  
Pavel S. Dmitrenok ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Degradation Products ◽  
Lethal Dose ◽  
Oxidative Degradation ◽  
Degradation Process ◽  
Oxidation Products ◽  
Chemical Mechanism ◽  
Ionization Mass ◽  
Echinochrome A ◽  
Esi Ms

Echinochrome A (Ech A, 1) is one of the main pigments of several sea urchin species and is registered in the Russian pharmacopeia as an active drug substance (Histochrome®), used in the fields of cardiology and ophthalmology. In this study, Ech A degradation products formed during oxidation by O2 in air-equilibrated aqueous solutions were identified, isolated, and structurally characterized. An HPLC method coupled with diode-array detection (DAD) and mass spectrometry (MS) was developed and validated to monitor the Ech A degradation process and identify the appearing compounds. Five primary oxidation products were detected and their structures were proposed on the basis of high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as 7-ethyl-2,2,3,3,5,7,8-heptahydroxy-2,3-dihydro-1,4-naphthoquinone (2), 6-ethyl-5,7,8-trihydroxy-1,2,3,4-tetrahydronaphthalene-1,2,3,4-tetraone (3), 2,3-epoxy-7-ethyl-2,3-dihydro-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone (4), 2,3,4,5,7-pentahydroxy-6-ethylinden-1-one (5), and 2,2,4,5,7-pentahydroxy-6-ethylindane-1,3-dione (6). Three novel oxidation products were isolated, and NMR and HR-ESI-MS methods were used to establish their structures as 4-ethyl-3,5,6-trihydroxy-2-oxalobenzoic acid (7), 4-ethyl-2-formyl-3,5,6-trihydroxybenzoic acid (8), and 4-ethyl-2,3,5-trihydroxybenzoic acid (9). The known compound 3-ethyl-2,5-dihydroxy-1,4-benzoquinone (10) was isolated along with products 7–9. Compound 7 turned out to be unstable; its anhydro derivative 11 was obtained in two crystal forms, the structure of which was elucidated using X-ray crystallography as 7-ethyl-5,6-dihydroxy-2,3-dioxo-2,3-dihydrobenzofuran-4-carboxylic acid and named echinolactone. The chemical mechanism of Ech A oxidative degradation is proposed. The in silico toxicity of Ech A and its degradation products 2 and 7–10 were predicted using the ProTox-II webserver. The predicted median lethal dose (LD50) value for product 2 was 221 mg/kg, and, for products 7–10, it appeared to be much lower (≥2000 mg/kg). For Ech A, the predicted toxicity and mutagenicity differed from our experimental data.

scholarly journals Characterization of forced degradation products of toloxatone by LC-ESI-MS/MS

2018 ◽  
Vol 26 (4) ◽  
pp. 467-480 ◽  
Author(s):  
Robert Skibiński ◽  
Jakub Trawiński ◽  
Łukasz Komsta ◽  
Diana Murzec
Keyword(s):  
Degradation Products ◽  
Forced Degradation ◽  
Esi Ms
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