(2R,3R)-5,7-Dihydroxy-2-{3,4,6-trihydroxy-5-oxo-1-[(2R,3R)-3,5,7-trihydroxy-3,4-dihydro-2H-chromen-2-yl]-5H-benzo[7]annulen-8-yl}-3,4-dihydro-2H-chromen-3-yl 3,4,5-trihydroxybenzoate