PXR competitive-binding activities of 10 (vinblastine), 12 (deacetyl vinblastine), 13 (catharanthine), 15 (catharanthinic acid), 14 (vindoline), and 16 (deacetyl vindoline) in the 4 (BODIPY FL vinblastine)-based
PXR binding assay. (A) Representative inhibitory activities of individual
chemicals along with negative control DMSO and positive control 1 (TO901317, 10 μM). (B) Dose–response curves
of 1 (TO901317), 10 (vinblastine), 15 (catharanthinic acid), 14 (vindoline), and 16 (deacetyl vindoline).