suggesting that the hydroxy groupwas replaced by a ketone
at position C-3″. The HMBC correlations of H-1″ (δH 5.01) with
C-7 (δC 163.0), C-8, (δC 103.5), and C-9 (δC 156.2) indicated that
the sugar moiety was located at position C-8. In addition, H-1″
(δH 5.01) correlated with C-3″ (δC 205.5), H-4″ (δH 4.04)
correlated with C-5″ (δC 79.0), C-6″ (δC 19.8) and C-3″ (δC
205.5). Therefore, the ketone carbon in 2 was located at position
C-3″. Furthermore, the coupling patterns of H-1″ (d, J =10.0 Hz)
and H-1‴ (s) indicated the sugar moiety had 1″-β and
1‴-α configurations, respectively [26]. Thus, the structure
of 2 was established as apigenin-8-C-β-[6-deoxy-2-O-(α-
L-rhamnopyranosyl)-ribo-hexopyranos-3-uloside].