Permeability Study of Polyphenols Derived from a Phenolic-Enriched Hibiscus sabdariffa Extract by UHPLC-ESI-UHR-Qq-TOF-MS

Previous findings on the capacity of Hibiscus sabdariffa (HS) polyphenols to ameliorate metabolic disturbances justify the necessity of studies oriented to find the potential metabolites responsible for such an effect. The present study examined the intestinal epithelial membrane permeability of polyphenols present in a phenolic-enriched Hibiscus sabdariffa extract (PEHS), free and encapsulated, using the Caco-2 cell line. Additionally, selected polyphenols (quercetin, quercetin-3-glucoside, quercetin-3-glucuronide, and N-feruloyltyramine) were also studied in the same absorption model. The powerful analytical platform used ultra-high-performance liquid chromatography coupled with ultra-high-resolution quadrupole time-of-flight mass spectrometry (UHPLC-ESI-UHR-Qq-TOF-MS), and enabled the characterization of seven new compounds in PEHS. In the permeation study, only a few compounds were able to cross the cell monolayer and the permeability was lower when the extract was in an encapsulated form. Pure compounds showed a moderate absorption in all cases. Nevertheless, these preliminary results may need further research to understand the complete absorption mechanism of Hibiscus polyphenols.
This work was supported by projects AGL2011-29857-C03-02 and AGL2011-29857-C03-03 (Spanish Ministry of Science and Innovation), in addition to P10-FQM-6563 and P11-CTS-7625 (Andalusian Regional Government Council of Innovation and Science), PROMETEO/2012/007 and ACOMP/2013/093 (Generalitat Valenciana), and CIBER (CB12/03/30038, Fisiopatología de la Obesidad y la Nutrición, CIBERobn, Instituto de Salud Carlos III). The authors are grateful to the Spanish Ministry of Science and Innovation for the grant FPI (BES-2009-028128), and the Spanish Ministry of Economy and Competitiveness (MINECO) in association with the European Social Fund (FSE) for the contract PTQ-13-06429. MH is a recipient of a VALi + D fellowship from GV (ACIF/2010/162). The authors are especially grateful to Bruker Daltonik GmbH (Bremen, Germany) for their help and support during this research.