When the isomers associated with the peak at 4.40 min were treated with a methanolic solution of 0.5 M NaOH for 5 min followed by neutralization with HOAc and separated using HPLC (NH2), a single peak (tR = 9.1 min) was observed.
An accurate mass (negative ESI) gave a molar mass of 1039.3229 corresponding to a molecular formula of C43H59O29 (calculated 1039.3142).
When the peak at 4.70 min was treated under the same conditions, a single peak (tR = 8.00) was obtained. Accurate mass of that peak gave an m/z of 1039.3218, which corresponds to C43H59O29.