Identification of phase-II metabolites from human serum samples after oral intake of a willow bark extract
| Autor: | Josef Kiermaier, Guido Jürgenliemk, Susanne Reintjes, Monika Untergehrer, Jörg Heilmann |
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| Rok vydání: | 2018 |
| Předmět: |
Metabolite
Pharmaceutical Science Administration Oral Ferulic acid 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Salicin Tandem Mass Spectrometry Drug Discovery Humans Glycosides Benzyl Alcohols 030304 developmental biology Pharmacology Flavonoids 0303 health sciences Chromatography Plant Extracts Catechin Salix Eriodictyol Salicyluric acid Healthy Volunteers Complementary and alternative medicine chemistry 030220 oncology & carcinogenesis Inactivation Metabolic Plant Bark Molecular Medicine Glucuronide Salicylic acid Chromatography Liquid |
| Zdroj: | Phytomedicine : international journal of phytotherapy and phytopharmacology. 57 |
| ISSN: | 1618-095X |
| Popis: | Background Willow bark (Salicis cortex) is a herbal medicinal drug used to treat fever and pain, such as headaches and lower back pain. Until now, it has not been fully understood which compounds are responsible for the efficacy of the drug. Purpose Although salicylic acid is known as a metabolite of salicylic alcohol derivatives of willow bark in vivo, it has been shown in previous studies that its concentration is too low to account for the overall efficacy of Salicis cortex. The aim this study was to broaden the knowledge regarding phenolic phase-II metabolites after oral intake of a willow bark extract. Study design/methods Serum samples of a human pharmacokinetic study (Salicis cortex extract intake corresponding to 240 mg of total salicin, 10 volunteers, 12 h fasting time, controlled diet low in phenolics, and 12 blood withdrawals over a period of 24 h) were analyzed by LC-ESI-MS. A library of 142 possible metabolites associated with salicylic alcohol derivatives, flavonoids, and proanthocyanidins was used to characterize possible metabolization products. Their structures were confirmed by LC-ESI-MS experiments with reference compounds after a cleavage reaction using glucuronidase and sulfatase as well as by LC-MS/MS experiments. Results In the serum samples, phase-II metabolites of naringenin (2x glucuronides, 2x sulfates, 2x mixed glucuronide-sulfates), eriodictyol (3x glucuronides, 1x sulfate), taxifolin (1x sulfate), catechin (1x sulfate, 1x mixed glucuronide sulfate), ferulic acid (1x sulfate), hydroxyphenyl-propionic acid (1x sulfate), dihydroxyphenyl-valerolactone (1x sulfate), saligenin (1x glucuronide, 1x sulfate), salicylic acid (1x sulfate, 1x unconjugated, 1x salicyluric acid), and catechol (1x glucuronide, 1x sulfate) were characterized. Because taxifolin, dihydroxyphenyl-valerolactone, ferulic acid, and hydroxyphenyl-propionic acid could not be detected in the willow bark preparation, they could be metabolization products of genuine flavanones and flavan-3-ols as well as coumaric acid or C-ring cleavage products of flavonoids, which were present in the extract. No phase-II metabolites of procyanidins and no genuine flavonoid glycosides were detected in all serum samples. Conclusion This is the first study to identify human metabolites of flavonoids, proanthocyanidins and salicylic alcohol derivatives of Salicis cortex beside salicylic acid or catechol. For the most characterized metabolites, anti-inflammatory activity has been described in the literature, and the present results are an important step in understanding the anti-inflammatory efficacy of willow bark in vivo. |
| Databáze: | OpenAIRE |
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