(1′R,2R,4′S,5R,8′R,10′E,12′R,13′S,14′E,16′E,20′R,21′R,24′S)-12′,21′,24′-Trihydroxy-5-(hydroxymethyl)-6,11′,13′,22′-tetramethyl-3,4,5,6-tetrahydro-2′H-spiro[pyran-2,6′-[3,7,19]trioxatetracyclo[15.6.1.1 ~4,8~.0~20,24~]pentacosa[10,14,16,22]tetraen]-2′-one