I have isolated this flavonoid glycoside from the ethyl acetate fraction of the leaf extract. The C-13, and DEPT135 NMR experiments shows there are 2 carbonyl peaks, 16 other C- peaks as well as 12-Cs peaks of sugar.
I do not think so. It appears that you have a mixture of two isomeric flavonoid glycosides, whose structures and polarities are probably very similar. To solve this doubt, I see you need to submit you sample into a analytical RP-HPLC and see the chromatographic profile: the amount of major peaks will reveal if you have one, two or more compounds. Additionally, you can analyse your sample by MS under wild conditions such as FAB, and then check the mass(es) of your unique constituent / major constituents. If a dimer exists, so you will clearly see it on your mass spectrum by a compatible [M+] or [M+1] peak(s).