Pheochromocytoma
Demetrius Pertsemlidis, William B. Inabnet III, Michel Gagner in Endocrine Surgery, 2017
All medications should be screened, and those known to falsely elevate or suppress the catecholamines or their metabolite concentrations in the plasma or urine should be stopped for at least 1 week. Phenoxybenzamine and tricyclic antidepressants are major causes of false-positive elevation of norepinephrine and its metabolites [32]. Labetalol, one of the frequently used antihypertensive drugs, interferes with catecholamine and metanephrine assays and should be stopped 1 week before sampling plasma or urine [33]. Acetaminophen interferes with the analytical method of plasma normetanephrine assay and should be stopped several days before blood is collected [33]. Metoclopramide raises the arterial pressure, through catecholamine hypersecretion, and may cause death. Alpha-methyl-DOPA, monoaminooxidase (MAO) inhibitors, amphetamine (phenylephrine, pseudoephedrine, and phenylpropalamine), cocaine, and calcium antagonists may interfere with assays of the parent catecholamines and their metanephrines in the plasma and urine [33]. Dietary caffeic acid, a catechol ingredient in natural and decaffeinated coffee, and its metabolite dihydrocaffeic acid interfere with assays of plasma catecholamines [33].
Laccase-Mediated Synthesis of Novel Antibiotics and Amino Acid Derivatives
Peter Grunwald in Pharmaceutical Biocatalysis, 2019
The redox potentials of the ortho-dihydroxy aromatic acids listed in Table 8.4 range from 0.425 to 0.8 V and should have corresponding reactivities in laccase-mediated reactions (Mai et al., 2001). They should have comparable reactivities to the para-dihydroxy aromatic acids. Thus — as we already know from these para-substituted substrates — not only the redox potential and the reactivity influence the laccase-initiated amination, but in addition the structure of the substituents of the aromatic ring affect the extent of product formation. In the case of the methoxylated compounds listed in Table 8.4, probably, the amination cannot take place due to the missing quinoid intermediates which are formed from the para- and ortho-dihydroxylated substrates (Figs. 8.3 and 8.4) but not from methoxylated ones. Possible reaction steps during laccase-mediated reactions of ortho-dihydroxy aromatic acids 3,4-dihydroxybenzoic acid (64) (protocatechuic acid), 3,4-dihydroxyphenylacetic acid (65), 3-(3,4-dihydrox yphenyl)propionic acid (66) (dihydrocaffeic acid).
The Food Metabolome and Dietary Biomarkers
Dale A. Schoeller, Margriet S. Westerterp-Plantenga in Advances in the Assessment of Dietary Intake, 2017
Most biomarkers identified in metabolomic studies and listed in Table 15.3 are surrogates for acute food intake. They were most often identified in short-term intervention studies or in observational studies in which biomarker levels were compared to acute food intake as assessed with either 24HR or dietary records on the day when biospecimens were collected. Such biomarkers would not necessarily be effective in estimating habitual intake of the same foods. In a few recent studies, however, metabolites were tested against habitual food intake as measured with FFQs. Still, most biomarkers found to be associated with habitual food intake (e.g., proline betaine, 3-(3,5-dihydroxyphenyl)propanoic acid, methylhistidine, dihydrocaffeic acid or urolithin A) have elimination half-lives of 24 hours or less (Heinzmann et al. 2010; Sjolin et al. 1987; Manach et al. 2005). Significant associations between these markers and habitual (usual) food intake could therefore be explained by the frequent consumption of the corresponding foods (Edmands et al. 2015).
Comparing coagulation activity of Selaginella tamariscina before and after stir-frying process and determining the possible active constituents based on compositional variation
Published in Pharmaceutical Biology, 2018
Qian Zhang, Ya-Li Wang, Die Gao, Liang Cai, Yi-Yao Yang, Yuan-Jia Hu, Feng-Qing Yang, Hua Chen, Zhi-Ning Xia
Dihydrocaffeic acid and amentoflavone with 98% purity (determined with HPLC) was provided by PUSH Bio-technology Co., Ltd. (Chengdu, China). Platelet agonist thrombin (THR), arachidonic acid (AA) and collagen were obtained from Sigma (St. Louis, MO). Adenosine diphosphate (ADP) was the product of Wuhu Huaren Technology Co., Ltd. (Wuhu, China). Thrombin receptor activator peptide 6 (trap-6) was purchased from Nanjing Peptide Biotech Ltd. (Nanjing, China). Heparin sodium salt (185 USP units/mg) was bought from Shanghai Aladdin BioChem Technology Co., LTD (Shanghai, China). HPLC-grade acetonitrile and formic acid were obtained from Beijing InnoChem Science & Technology Co., Ltd. (Beijing, China). Yunnanbaiyao (YNBY) was a product of YunNanBaiYao Group Co., Ltd. (Kunming, China). Coagulation assay kit was purchased from Taizhou Steellex Biotechnology Co., LTD. (Taizhou, China). The water used for all the experiments was purified by water purification system (ATSelem 1820 A, Antesheng Environmental Protection Equipment Co., LTD., Chongqing, China). Unless otherwise specified, all other chemicals and solvents were guaranteed reagent grade and purchased from Sigma (St. Louis, MO).
Sour Cherries but Not Apples Added to the Regular Diet Decrease Resting and fMLP-Stimulated Chemiluminescence of Fasting Whole Blood in Healthy Subjects
Published in Journal of the American College of Nutrition, 2018
Piotr Bialasiewicz, Anna Prymont-Przyminska, Anna Zwolinska, Agata Sarniak, Anna Wlodarczyk, Maciej Krol, Jaroslaw Markowski, Krzysztof P. Rutkowski, Dariusz Nowak
HPLC analysis of 11 selected phenolics and their metabolites (dihydrocaffeic acid, vanillic acid, caffeic acid, homovanillic acid, hippuric acid, 4-hydroxyhippuric acid, 3-hydroxyhippuric acid, chlorogenic acid, 3,4-dihydroxybenzoic acid, 3-hydroxyphenylacetic acid, urolithin A) in fasting plasma revealed no significant changes in response to apple and sour cherry consumption (data not shown). Similarly, phenolic concentrations in spot morning urine in apple consumers did not change over the study period. However, urinary concentrations of 3-hydroxyhippuric acid, 4-hydroxyhippuric acid, and chlorogenic acid increased significantly after the introduction of cherries to the diet (Table 4). Median concentrations of 3-hydroxyhippuric acid and chlorogenic acid increased 1.16 and 1.29 times after 15 days of sour cherry consumption (25th day) in comparison to the values found on the 10th day and returned to baseline after 10 days of wash-out, respectively. On the other hand, urinary levels of hippuric acid tended to decrease after diet supplementation with sour cherries (Table 4).
Identification of the metabolites of isochlorogenic acid A in rats by UHPLC-Q-Exactive Orbitrap MS
Published in Pharmaceutical Biology, 2020
Kaiyan Gong, Yuan Yang, Kailin Li, Lian Zhu, Xinjun Zhi, Wei Cai
Peaks 5 and 6 were eluted at 6.44 and 7.14 min, respectively. Both displayed the same pseudomolecular ions [M–H]− at m/z 258.99161 (−0.72 ppm, C9H7O7S), which yielded the base peak ion at m/z 179.034 by the loss of the SO3 moiety (80 Da). Their MS2 spectrum is consistent with the spectrum of caffeic acid (CA), therefore, they were tentatively characterised as sulphation products of CA. In the same way, peaks 1 and 4 were tentatively confirmed to be sulphation products of dihydrocaffeic acid (DHCA); peaks 8 and 10 were sulphation products of dihydroferulic acid (DHFA); and peak 13 was sulphation products of ferulic acid (FA).