Facile purification of milligram to gram quantities of condensed tannins according to mean degree of polymerization and flavan-3-ol subunit composition

Brown, R. H., Mueller-Harvey, I., Zeller, W. E., Reinhardt, L., Stringano, E., Gea, A., Drake, C., Ropiak, H. M., Fryganas, C., Ramsay, A. and Hardcastle, E. E. (2017) Facile purification of milligram to gram quantities of condensed tannins according to mean degree of polymerization and flavan-3-ol subunit composition. Journal of Agricultural and Food Chemistry, 65 (36). pp. 8072-8082. ISSN 0021-8561 doi: 10.1021/acs.jafc.7b03489

Abstract/Summary

Unambiguous investigation of condensed tannin (CT) structure-activity relationships in biological systems requires well-characterized, high-purity CTs. Sephadex LH-20 and Toyopearl HW-50F resins were compared for separating CTs from acetone/water extracts and column fractions analyzed for flavan-3-ol subunits, mean degree of polymerization (mDP) and purity. Toyopearl HW-50F generated fractions with higher mDP values and better separation of procyanidins (PC) and prodelphinidins (PD) but required a pre-purification step, more time for large scale purifications and gave poorer recoveries. Therefore, two gradient elution schemes were developed for CT purification on Sephadex LH-20 providing 146 - 2000 mg/fraction. Fractions were analyzed by thiolysis and NMR spectroscopy. In general, PC/PD ratios decreased and mDP increased during elution. 1H NMR spectroscopy served as a rapid screening tool to qualitatively determine CT enrichment and carbohydrate impurities present, guiding fractionation towards re-purification or 1H-13C HSQC NMR spectroscopy and thiolysis. These protocols provide options for preparing highly pure CT samples.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/72143
Identification Number/DOI	10.1021/acs.jafc.7b03489
Refereed	Yes
Divisions	Life Sciences > School of Agriculture, Policy and Development > Department of Animal Sciences > Animal, Dairy and Food Chain Sciences (ADFCS)- DO NOT USE
Publisher	American Chemical Society
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