Further work on the 40% fraction led to the isolation of 5,3′,5′-trihydroxy-3,6,7,4′-tetramethoxyflavone as the component responsible for a BCRP-inhibitory activity with an IC50 value of 14.67 μM and an ability to resensitize SN-38 resistant colon cancer cells. The gene discussed is ABCG2; the disease is colonic neoplasm.