(6Z,8Z,12R,12aS,14R,15aR,19aR)-5-acetyl-24-hydroxy-12a,17-dimethyl-2,3,12,12a,18,19-hexahydro-14H,15aH-spiro[1a,5:12,14-dimethanooxireno[8,9][1,6,12]trioxacyclooctadecino[3,4-d]chromene-13,2'-oxirane]-10,22(5H,22aH)-dione