with differences ascribed to the sugar moiety and suggested that a sugar war replaced
by arabinose
In the HMBC spectrum the proton of H-1
correlated with
In addition the coupling patterns of
indicated that both arabinose and rhamnose
configurations
therefore the structure of compound 3 was determined as apigenin
rhamnopyranosyl group was assigned to c-12. therefore, the structure of 4 was determined to be apigenin -8-trans-ethenyl-12-0-l-rhamnoside.