Structural interaction between ent -Sauchinone and STAT3. ent-Sauchinone was prepared from 4-(oxiran-2-yl) phenyl acetate, Pd(OAc)2 and tributyl phosphine (A). Pull-down assay identifies an interaction between the ent-Sauchinone and STAT3. ent-Sauchinone was conjugated with cyanogen bromide Epoxy-activated Sepharose 6B (B). Docking model of ent-Sauchinone with STAT3 as described in Materials and Methods (C and D).