Planta Med 2009; 75 - PE1
DOI: 10.1055/s-0029-1234562

New compounds from Metaxya rostrata (Kunth C. Presl)

KP Kainz 1, J Virtbauer 1, B Marian 2, H Kaehlig 3, O Donath 1, G Reznicek 1, L Krenn 1
  • 1Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
  • 2Department of Medicine 1, Institute of Cancer Research, Medical University Vienna, Borschkegasse 8a, 1090 Vienna, Austria
  • 3Institute of Organic Chemistry, University of Vienna, Währingerstrasse 38, 1090 Vienna, Austria

Two new compounds were isolated from the tree fern Metaxya rostrata, Metaxyaceae, a Costa Rican traditional herbal remedy against intestinal diseases. Until now only two polyphenols (cinnamtannin B-1 and aesculitannin B), two glycosides of phenolic acids (4-O-ß-D-glucopyranosyl-caffeic-acid and 4-O-ß-D-glucopyranosyl-p-trans-coumaric-acid), sugars and common sterols have been isolated from this plant [1,2].

Dried rhizomes were extracted by sonification with hot water and methanol. The lyophilisate was extracted sequentially with ethylacetate, butanol and methanol. The fractions were subjected to vacuum liquid chromatography (VLC) on silica gel using EtOAc/MeOH/H2O mixtures of increasing polarity as mobile phases to obtain 15 fractions [1].

Fraction 12, cytotoxic to SW 480 colorectal carcinoma cells, was subjected to gel permeation chromatography on Sephadex LH-20. From the resulting fraction A compounds KK1 (58mg) and KK5 (3mg) were isolated.

By detailed NMR and MS experiments the compounds were identified as (2E)-2-(6-hydroxyhexyliden)cyclopropyl-β-glucopyranoside (KK1) and (6E)-6[2-(β-glucopyranosyloxy)cyclopropylidene]hexanoic acid (KK5). The substances did not show cytotoxic activity. Thus, the cytotoxic activity of fraction 12 obviously is due to other compounds.

KK1

KK5

References: [1] Virtbauer, J. et al. (2008) Z. Naturforsch. 63c:469–475.

[2] Kainz, K.P. et al. (2009) Sci. Pharm. 77:in press