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A high-performance liquid chromatographic/ tandem mass spectrometric method was developed for the determination of the major bioactive flavonolignans in silymarin, a herbal remedy extracted from the milk thistle Silybum marianum. In this study, eight active components of silymarin with the same elemental composition, including silychristins A and B, silydianin, silybin A and B, isosilybin A and B and an unknown compound were completely separated. Furthermore, three additional components were detected and partly separated; presumably two silybin stereoisomers and one isosilybin stereoisomer. The collision-induced dissociation (CID) MS/MS spectra of these silymarin constituents were studied: the spectral similarity values of the component pairs were determined, and simple criteria were found for distinguishing the components.Keywords High-performance liquid chromatography Á Tandem mass spectrometry Á Milk thistle Á Silymarin Á Silybin Electronic supplementary material The online version of this article (

Our modified methods are now suitable for direct measurements of major protein and non-protein thiols/disulfides in the gastric mucosa or liver. A common element in the pathogenesis of chemically induced HML and in the mechanism of gastroprotective drugs seems to be the decreased ratios of reduced and oxidized glutathione as well as protein sulfhydryls and disulfides.

COPD is associated with elevated L-arginine, ADMA and SDMA serum levels. In patients with AECOPD, production of ADMA and SDMA are more pronounced presumably due to more severe hypoxic insult. Methylated arginine derivatives in the sera may help early recognition of AECOPD.

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This study has assessed the protective efficacy of

Background Chronic obstructive pulmonary disease (COPD) is related to endothelial dysfunction and the impaired generation of nitric oxide (NO) from L-arginine by the endothelial NO synthase (eNOS). The relationship between eNOS dysfunctionality and airway inflammation is unknown. We assessed serum asymmetric and symmetric dimethylarginine (ADMA and SDMA) and nitrite/nitrate concentrations, indicators of eNOS function, in patients with COPD and correlated them with markers of inflammation. Methods We recruited 15 control smokers, 29 patients with stable and 32 patients with exacerbated COPD requiring hospitalization (20 of them were measured both at admission and discharge). Serum L-arginine, ADMA, SDMA, nitrite and nitrate were measured and correlated with airway inflammatory markers (fractional exhaled nitric oxide concentration - F ENO, sputum nitrite and nitrate, sputum cellularity), serum C-reactive protein - CRP, white blood cell count, lung function and blood gases. ANOVA, t-tests and Pearson correlation were used (mean ± SD or geometric mean ± geometric SD for nitrite/nitrate). Results Serum L-arginine/ADMA, a marker of substrate availability for eNOS, was lower in stable (214 ± 58, p < 0.01) and exacerbated COPD (231 ± 68, p < 0.05) than in controls (287 ± 64). The serum concentration of SDMA, a competitor of L-arginine transport, was elevated during an exacerbation (0.78 ± 0.39 μM) compared to stable patients (0.53 ± 0.14 μM, p < 0.01) and controls (0.45 ± 0.14 μM, p < 0.001). ADMA correlated with blood neutrophil percentage ( r = 0.36, p < 0.01), F ENO ( r = 0.42, p < 0.01) and a tendency for positive association was observed to sputum neutrophil count ( r = 0.33, p = 0.07). SDMA correlated with total sputum inflammatory cell count ( r = 0.61, p < 0.01) and sputum neutrophil count ( r = 0.62, p < 0.01). Markers were not related to lung function, blood gases or CRP. L-arginine/ADMA was unchanged, but serum SDMA level decreased (0.57 ± 0.42 μM, p < 0.05) after systemic steroid treatment of the exacerbation. Serum nitrite level increased in stable and exacerbated disease (4.11 ± 2.12 and 4.03 ± 1.77 vs. control: 1.61 ± 1.84 μM, both p < 0.001). Conclusions Our data suggest impaired eNOS function in stable COPD, which is transiently aggravated during an exacerbation and partly reversed by systemic steroid treatment. Serum ADMA and SDMA correlate with airway inflammatory markers implying a possible effect of anti-inflammatory th...