“…Concerning cancer, since the beginning of chemotherapy in the 1940s to date, about 75% of anticancer drugs approved world-wide are natural products or their synthetic derivatives (Newman and Cragg, 2012). In an effort to find out anticancer compounds from plants, for targeting MDR cancer cells, our group has been given particular attention on the development of MDR reversal compounds (Reis et al, 2015;Paterna et al, 2016;Ramalhete et al, 2016;Reis et al, 2016;Reis et al, 2017;Ferreira et al, 2018a;Ferreira et al, 2018b;Paterna et al, 2018;Ramalhete et al, 2018). Duo to the high and unusual chemical diversity of their metabolites, many of which coupled with strong biological properties, we have given particular attention to Euphorbia species (Euphorbiaceae), which are well known since ancient times for their use in folk medicine worldwide, namely, to cure cancer, tumors, and warts (Hartwell, 1969;Ernst et al, 2015).…”