Pleurospermum austriacum (L.) Hoffm. is a plant of montane gorges and subalpine meadows of Central Europe and belongs to a genus grouped within Apiaceae-Smyrnieae, the majority of its species occurring in the mountain ranges of Eastern India.
The hexane-diethylether-methanol (1:1:1) extract of the underground parts (300 g) afforded a series of closely related C17-polyacetylenes and one C18-polyacetylene aldehyde (1-12). Fractionation by CC (hexane with increasing amounts of diethylether), followed by MPLC (hexane, ethylacetate) led to the isolation of pure polyacetylenes which were characterized by UV, IR, MS, 1H-, and 13C-NMR spectroscopy.
1, 3, 6, 8, and 10-12 also occur in Oenanthe crocata L. [1]. 6 has been reported from Cicuta virosa L. [2] and Opopanax chironium Kch. [3]. 4 from Heracleum mantegazzianum Somm. & Lev. [4] and falcarindiol (5) is the most widespread polyacetylene detected in the Apiaceae [5]. Contrary, 1 has been detected in the Asteraceae only [6,7]. 7 and 9 are hitherto undescribed isomers of 8 and have been obtained by cyclic MPLC. The differences in the 1H- and 13C-spectra of 8 and 9 are confirmed by MS fragmentation corroborating the position of the hydroxyl group on carbon atom l4 and l5 respectively.
Bioassaying the antibacterial activity against gram-positive bacteria in vitro, using Staphylococcus aureus, falcarindiol (5), the most widespread polyacelylene found in the Apiaceae, showed the highest activity in comparison to the other rarely occurring derivatives.
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