Acylated Iridoid Glycosides from Verbascum lasianthum

Authors: ZELİHA Ş. AKDEMİR, İ. İREM TATLI, ERDAL BEDİR, IKHLAS A. KHAN

Abstract: From the roots of Verbascum lasianthum Boiss. ex Bentham 4 catalpol derivatives, 6-O-(\alpha-L-rhamnopyranosyl)-catalpol (1), verbascoside A [= 6-O-(4''-O-trans-p-methoxycinnamoyl)-\alpha -L-rhamnopy- ranosylcatalpol] (2), pulverulentoside I [= 6-O-(3''-O-acetyl-2''-O-trans-p-methoxycinnamoyl)-\alpha -L-rham-nopyranosylcatalpol] (3), and buddlejoside A_{5} [= 6-O-(2''-O-acetyl-3''-O-trans-p-methoxycinnamoyl)-\alpha -L-rhamnopyranosylcatalpol] (4), as well as aucubin (5) and an aucubin derivative, unduloside III [= 6-O-(3''-O-trans-p-methoxycinnamoyl)- \alpha-L-rhamnopyranosylaucubin] (6), were isolated and characterized. The structure elucidation of the compounds was established on the basis of spectroscopic evidence. Buddlejoside A_{5} (4) was found for the first time in the genus Verbascum.

Keywords: Verbascum lasianthum Boiss. ex Bentham, Scrophulariaceae, iridoid glycosides, 6-O-(\alpha-L-rhamnopyranosyl)-catalpol, verbascoside A, pulverulentoside I, buddlejoside A_{5}, aucubin, unduloside III

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