synergistic effect with conventional chemotherapeutic drugs is a fact already reported, in various types of cancer, by numerous authors, namely in pancreatic (Espey et al., 2011), prostate (Gilloteaux et al., 2014), lung (Lee et al., 2017), breast (Kurbacher et al., 1996; Wu et al., 2017) and ovarian (Ma et al., 2014) cancers.