Phenylbenzofuran-Type Stilbenoids From Stemona Species

Five new phenylbenzofuran-type stilbenoids, stemofurans S-W (1-5), were isolated from underground parts of four Stemona species collected in Thailand and Australia together with the known stemofurans A-C, G, E, J, M, the stilbostemins A-D, F, the stemanthrenes A-D, dihydropinosylvin, pinosylvin, and 4'-methylpinosylvin. The chemical structures of the new compounds were elucidated by H-1 NMR and C-13 NMR spectroscopy and mass spectrometry. In accordance with previous reports all compounds were characterized by C-methylations of the aromatic rings. Stemofurans S (1) and U (3) showed an unusual hydroxylation at position C-4', a hitherto unknown substitution of Stemona stilbenoids. (C) 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.