Figure 4

Electronegative potentials influence the affinity of the Position 7-substituted FL118 analogues for ABCG2 binding. A, structures of FL118 analogues with B ring substitutions. B, correlation between electronegativity of chemical groups (χ, Pauling units, calculated using the method of Huheey) and the ratio of EC50 of drug alone / EC50 drug + Ko143.