8,9,10,11,12,13-hexahydroxy-6,15-dioxo-1-{[(3,4,5-trihydroxybenzoyl)oxy]methyl}-3,4,4a,6,15,16a-hexahydro-1H-dibenzo[f,h]pyrano[3,4-b][1,4]dioxecine-3,4-diyl bis(3,4,5-trihydroxybenzoate)