Adjuvant activity of the P2Et fraction on the K562 and MCF7 cell lines. K562 (A) or MCF7 (B) cells were treated with the P2Et fraction or ethanol (negative control) for 6 h, washed and treated with doxorubicin (Dx), vincristine (Vt), camptothecin (Ct) or taxol (Tx) at the concentrations shown over a 48 h period. Cell cytotoxicity was estimated using the MTT assay. Data represent three independent experiments. *** (p < 0.001).