This phytocompound is extracted from the roots of Erythroxylum pervillei. It selectivelykills the multidrug-resistant KB-V1 (oral epidermoid) cancer cells in the presenceof chemotherapeutic agent vinblastine (Shoeb 2006). It could restore thesensitivity of vinblastine in cultured multidrug-resistant KB-V1 and CEM/VLBcells, at a half maximal inhibitory concentrations of 0.36 μM and 0.02 μM,respectively (Mi et al. 2001). It is more effective than verapamil in reversingmultidrug resistance in KB-8-5 cells when tested in the in vivo hollow fiber model(Balunas and Kinghorn 2005).
