6.

New compounds from the tree fern Metaxya rostrata C. Presl

Kerstin Kainz, Martin Zehl, Johanna Bleier, Barbara Merkinger, Teresa Pemmer, Natalie Schmidt, Johannes Winkler, Hanspeter Kählig and Liselotte Krenn

Department of Pharmacognosy, University of Vienna, Althanstraße 14, 1090 Vienna, Austria

Institute of Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria

Department of Medicinal Chemistry, University of Vienna, Althanstraße 14, 1090 Vienna, Austria

Institute of Organic Chemistry, University of Vienna, Währingerstraße 38, 1090 Vienna, Austria

Abstract: Four new natural compounds, namely 2-deprenyl-7-hydroxy-rheediaxanthone B, (2E)-2-(hydroxyl hexyliden)-cyclopropyl-1 ® 3-diglucoside and (6E)-6[2-( β -gluco­pyranosyloxy)-cyclopropyliden] hexanoic acid methylester as well as the first glucocerebroside from a fern, (4E)-1-O-(β-glucopyranosyl)-N-(2’-hydroxy­tetra­cosanoyl)-4,8-sphingadienine (d18:2/h24:0-GlcCer) , were isolated for the first time from the rootlets of the tree fern Metaxya rostrata C. Presl. Two of these compounds contain a very rare cyclopropyliden structure which until now is only known from two other compounds from this plant. In addition, this is the first report of the tannin pro­anthocyanidin A2 and the triterpenes squalene and fern-9(11)-ene in this tree fern, of which the two latter were isolated from the leaves. The structures of all compounds were elucidated on the basis of detailed spectroscopic and mass spectrometric analyses, including 1D-, 2D-NMR and HR Q-TOF-MS.

Keywords: Metaxya rostrata; cyclopropyliden derivatives; glucocerebroside; xanthone; spectroscopic analyses . © 2014 ACG Publications. All rights reserved.