Efficient preparative isolation and identification of walnut bioactive components using high-speed counter-current chromatography and LC-ESI-IT-TOF-MS. Food Chemistry. Sep 1, 2014 Epub Mar 1, 2014. Grace MH1, Warlick CW1, Neff SA1, Lila MA2.
1Plants for Human Health Institute, Food Bioprocessing and Nutritional Sciences, North Carolina State University, North Carolina Research Campus, Kannapolis, NC 28081, USA.; 2Plants for Human Health Institute, Food Bioprocessing and Nutritional Sciences, North Carolina State University, North Carolina Research Campus, Kannapolis, NC 28081, USA.
Preparative isolation of complex mixtures of compounds from walnut polar extracts was established by a combination of high-speed counter-current chromatography (HSCCC) and electrospray ionization-ion trap-time of flight mass spectrometry (ESI-IT-TOF-MS). Compounds were isolated after a solvent optimisation selection based on solute distribution in a biphasic solvent system. Isolation was achieved through one or two successive HSCCC runs, and final purification on Sephadex LH-20. Isolated compounds included ellagitannins (1-11), gallic acid (12), dicarboxylic acid glucosides (13-15), hydrojuglone glucoside (16), catechin (17), procyanidin B2 (18), and megasterone glucosides (19-20). Praecoxin D (4) was isolated for the first time from walnut, while praecoxin A methyl ester (5) and glansreginin A n-butyl ester (14) are newly identified compounds. The purity and identity of isolated compounds were confirmed by NMR and HPLC-ESI-MS/MS. These results provided a foundation for in depth characterisation of walnut compounds and offered an efficient strategy for isolation of potentially health-relevant phytochemicals from walnuts.
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PMID: 24731336 [PubMed – in process]