Buegenine (56) (Figure 18), derived from Zanthoxylum buesgenii, is cytotoxic in nine cancer cell lines, including leukemic cancer cells CCRF-CEM and CEM/ADR5000, breast cancer cell MDA-MB231 and its resistant subline MDA-MB231/BCRP, colon cancer cell HCT-116p53+/+ and its resistant subline HCT-116p53−/−, glioblastoma U87MG and its resistant subline U87MGΔEGFR, HepG2 hepatoma cells, and AML12 normal liver cells. Here, ABCG2 is linked to cancer.