Planta Med 2013; 79 - PI72
DOI: 10.1055/s-0033-1352161

Isolation & Structure Elucidation of Acylphloroglucinols from Hypericum amblycalyx Coustur. & Gand.

A Mathioudaki 1, M Löhr 2, S Schmidt 2, G Jürgenliemk 2, H Skaltsa 1, J Heilmann 2
  • 1Department of Pharmacognosy & Chemistry of Natural Products, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, 157 71, Athens, Greece
  • 2University of Regensburg, Pharmaceutical Biology, 93051 Regenburg, Germany

Acylphloroglucinols are a common class of bioactive phenolic compounds and can be found in the familiy Hypericaceae. The large structural diversity results from different kinds of linked acyl-moieties as well as different numbers of prenyl- or geranyl-moieties resulting in mono-, bi- & tricyclic compounds. The aim of this project was to determine the acylphloroglucinol spectrum of Hypericum amblycalyx which is an endemic plant growing in the east of Crete. It is taxonomically classified in the sectio Coridium (section 19) [1]. By 1H-NMR-guided fractionation, four acylphloroglucinol derivatives were isolated using silica- and RP18-flash chromatography and semi-prep HPLC, and their structures were confirmed by modern spectroscopy (1D- and 2D-NMR, ESI-MS): the two monocyclic derivatives 4-geranyl-2-(2'-methylbutyryl)-phloroglucinol and 4-geranyl-4-(2'-isobutyryl)-phloroglucinol, as well as two bicyclic compounds 1-[(2R*, 3S*)-3,5,7-trihydroxy-2-methyl-2-(4-methylpent-3-enyl)chroman-8-yl]-2-methylbutan-1-one and 1-[(2R*, 3S*)-3,5,7-trihydroxy-2-methyl-2-(4-methylpent-3-enyl)chroman-8-yl]-2-methyl-propan-1-on. All identified acylphloroglucinols are also described for the previously investigated H. empetrifolium [2, 3], belonging to the same section, i.e. Coridium; these data give evidence to their taxonomic correlation.

References:

[1] Robson N. K. B., 2010. Studies in the genus Hypericum L. (Hypericaceae) 5 (2). Sections 17. Hirtella to 19. Coridium. Phytotaxa 2010; 4: 127 – 258;

[2] Schmidt S., Jürgenliemk G., Skaltsa H., Heilmann J., 2012a. Phloroglucinol derivatives from Hypericum empetrifolium with antiproliferative activity on endothelial cells. Phytochemistry 77: 218 – 225;

[3] Schmidt S., Jürgenliemk G., Skaltsa