Planta Med 2011; 77 - PG38
DOI: 10.1055/s-0031-1282522

Phytochemical investigation of Himatanthus sucuuba bark leading to the identification of novel and anti-inflammatory compounds

B Waltenberger 1, J Mihály Bison 2, T Gelbrich 3, UJ Griesser 3, VN Bochkov 2, BR Binder 2, JM Rollinger 1, H Stuppner 1
  • 1Institute of Pharmacy, Pharmacognosy and Center for Molecular Biosciences, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
  • 2Institute of Vascular Biology and Thrombosis Research, Medical University of Vienna, Schwarzspanierstr. 17, 1090 Wien, Austria
  • 3Institute of Pharmacy, Pharmaceutical Technology, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria

Himatanthus sucuuba (Spruce ex Müll. Arg.) Woodson (Apocynaceae) is used in the Amazonian region for the treatment of inflammatory diseases [1]. The bark of this medicinal plant was phytochemically investigated guided by an LPS/TNF stimulated assay measuring E-selectin and IL-8. Out of bioactive fractions 11 constituents were isolated and identified by MS and 1D and 2D NMR experiments as iridoids (plumericin, plumieridin, allamandicin, and the new natural product (2'R,3R,4R,4aS,7aR)-methyl 3-hydroxy-4'-((S)-1-hydroxyethyl)-5'-oxo-3,4,4a,7a-tetrahydro-1H,5'H-spiro[cyclopenta[c]pyran-7,2'-furan]-4-carboxylate), flavonoids (biochanin A, dihydrobiochanin A, dalbergioidin, naringenin, ferreirin, and dihydrocajanin), and the lignan pinoresinol. Except for plumericin and pinoresinol this is the first time these compounds are reported to be isolated from Himatanthus sucuuba. The structure of the new iridoid was determined using X-ray crystallography. Interestingly, NMR experiments showed the presence of two compounds indicating stereochemical conversion.

The isolated constituents were analyzed for their anti-inflammatory activity. They showed only moderate or no effects with the exception of plumericin which exhibited dose-dependent inhibitory activity on LPS or TNF induced expression of IL-8 and E-selectin in the low µM range.

In conclusion, several known components were isolated from Himatanthus sucuuba for the first time together with one new natural product. Plumericin revealed as the most active compound in this general anti-inflammatory assay. The elucidation of the molecular mechanism of action is currently under evaluation.

Acknowledgement: This work was granted by the Austrian Science Fund (S10703).

References: 1. Amaral ACF et al. (2007) Pharmacogn Rev 1: 305–313.