The QTOF-MS spectrum of 5 gave the molecular formula of
C27H30O12 from the pseudomolecular ion peak at m/z 569.1638
[M + Na]+. The 1D and 2D NMR spectroscopic patterns of 5 were
similar to those of 4, displaying a 5,7-dihydroxy-flavone, a
C-linked b-boivinopyranoside and an O-linked b-D-glucopyranoside.
The difference between 4 and 5 was the C-glycosidic linkage
of the b-boivinopyranosyl group to the aglycone, which was
confirmed by the HMBC correlations of H-100 (dH 5.71) to C-700
(dC 160.1), C-800 (dC 160.1) and C-900 (dC 160.1), indicating that the
boivinosyl group was linked to the C-8 position. Thus, compound
5 was identified as 5,7-dihydroxyflavone 7-O-b-D-glucopyranosyl-
8-C-b-boivinopyranoside.
3. Conclusions