Comprehensive analysis of commercial willow bark extracts by new technology platform: Combined use of metabolomics, high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance spectroscopy and high-resolution radical scavenging assay

Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
Journal of Chromatography A (Impact Factor: 4.26). 09/2012; 1262:130-7. DOI: 10.1016/j.chroma.2012.09.013
Source: PubMed

ABSTRACT Here, proof-of-concept of a new analytical platform used for the comprehensive analysis of a small set of commercial willow bark products is presented, and compared with a traditional standardization solely based on analysis of salicin and salicin derivatives. The platform combines principal component analysis (PCA) of two chemical fingerprints, i.e., HPLC and (1)H NMR data, and a pharmacological fingerprint, i.e., high-resolution 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS(+)) reduction profile, with targeted identification of constituents of interest by hyphenated HPLC-solid-phase extraction-tube transfer NMR, i.e., HPLC-SPE-ttNMR. Score plots from PCA of HPLC and (1)H NMR fingerprints showed the same distinct grouping of preparations formulated as capsules of Salix alba bark and separation of S. alba cortex. Loading plots revealed this to be due to high amount of salicin in capsules and ampelopsin, taxifolin, 7-O-methyltaxifolin-3'-O-glucoside, and 7-O-methyltaxifolin in S. alba cortex, respectively. PCA of high-resolution radical scavenging profiles revealed clear separation of preparations along principal component 1 due to the major radical scavengers (+)-catechin and ampelopsin. The new analytical platform allowed identification of 16 compounds in commercial willow bark extracts, and identification of ampelopsin, taxifolin, 7-O-methyltaxifolin-3'-O-glucoside, and 7-O-methyltaxifolin in S. alba bark extract is reported for the first time. The detection of the novel compound, ethyl 1-hydroxy-6-oxocyclohex-2-enecarboxylate, is also described.

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    • "Classification of grapes cultivars 1 H, JRES NMR Phenolic acids [51] Classification of licorice species 1 H, 2D ROESY Triterpenoid saponins [66] Classification of hops cultivars 2D HMBC Bitter acids [82] Classification of Hypericum species 1 H, HSQC, HMBC Phloroglucinol derivatives [68] Classification of Salix species in relation to activity LC–SPE–NMR DPPH assay Salicin, phenolic compounds [102] "
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    Journal of Advanced Research 11/2014; 6(1). DOI:10.1016/j.jare.2014.10.003
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    • "Antioxidant activity of Salix bark was widely studied [24, 26, 27], but comparative analysis of results was difficult due to different ways of its measure and expression. And so, antiradical activity of bark of S. aegyptiaca (depending on the extraction system) ranged from 10 to 105 mg quercetin equivalent/d DM [26]. "
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    The Scientific World Journal 02/2014; 2014:782763. DOI:10.1155/2014/782763 · 1.73 Impact Factor
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    • "Metabolomics utilizes classical analytical techniques to probe chemical fingerprints and concentration levels of metabolites in the investigated samples. Different analytical tools have been used in metabolomics research including Fourier transform infrared (FT-IR) spectroscopy (Rehman et al. 2012; Ahmed et al. 2011; Corte et al. 2010; Gidman et al. 2003; Scott et al. 2010), mass spectrometry (MS) (Puccio et al. 2013; Zhu et al. 2013; Lin et al. 2010; Riccio et al. 2010; Scheltema et al. 2009; Wilson et al. 2005), high-performance liquid chromatography (HPLC) (Agnolet et al. 2012; Defernez et al. 2004) and nuclear magnetic resonance (NMR) spectroscopy. Mass spectrometry and NMR spectroscopy are the most common analytical techniques in metabolomics, employed since at least the early 1970s to investigate disease processes and biological mechanisms through metabolic profiling (Devaux et al. 1971; Fan 1996). "
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