PLANT METABOLITES - NEW SESQUITERPENE AND IONONE GLYCOSIDES FROM ERIOBOTRYA-JAPONICA

In a previous paper we described the isolation of four nerolidol glycosides 1-4 from Eriobotrya japonica collected in China. Here we report the isolation of seven glycosides 5-11, five of which (5-7, 10, and 11) are new natural products, from E. japonica collected in Southern Italy. Compounds 5-7 are sesquiterpene glycosides characterized by nerolidol (5) or isohumbertiol (6 and 7) as aglycones and by branched oligosaccharidic chains made up of one beta-D-glucopyranosyl and three alpha-L-rhamnopyranosyl units which link trans-feruloyl ester moieties in compounds 5 and 7. Analysis of the oligosaccharide structures was achieved by 2D spectral analysis including H-1-H-1 correlated spectroscopy (COSY), H-1-C-13 direct chemical shift correlations (HETCOR), and 2D-Homonuclear Hartmann-Hahn spectroscopy (HOHAHA). Compounds 8-11 were characterized as ionone-derived glycosides by chemical and spectral methods.