Iridoid glycosides from the leaves of Sambucus ebulus

Six new iridoid glycosides (1-6) of the "Valeriana type" were isolated from leaves of Sambucus ebulus. The structures were elucidated by 1D- and 2D-NMR spectroscopy, mass spectrometry, and chemical degradation methods as 10-O-acetylpatrinoside-aglycone-11-O-[4''-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-ribohexo-3-ulopyranoside] (1), 7-O-acetylpatrinoside-aglycone-11-O-[4''-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-ribohexo-3-ulopyranoside] (2), 10-O-acetylpatrinoside-aglycone-11-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-ribohexo-3-ulopyranoside] (3), patrinoside-aglycone-11-O-[4''-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-ribohexo-3-ulopyranoside] (4), 10-O-acetylpatrinoside-aglycone-11-O-[4''-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside] (5), and patrinoside-aglycone-11-O-2'-deoxy-beta-D-glucopyranoside (6). Compounds 1-4 represent the first examples of acylated iridoid diglycosides bearing the uncommon D-ribohexo-3-ulopyranosyl sugar moiety. Compound 6 is the first iridoid glycoside with a 2-deoxy-D-glucopyranosyl sugar moiety.