Phytonanomedicine: a novel avenue to treat recurrent cancer by targeting cancer stem cells.

Research suggests that tumor relapse and metastasis is caused by minor population of tumor-initiating cells called cancer stem cells (CSCs), which exhibit self-renewability, quiescence, antiapoptosis, and drug resistance. Conventional chemotherapeutics target rapidly proliferating cells but fail to exert cytotoxic effects on CSCs, thus enriching them and driving metastasis and relapse. Hence, targeting CSCs is essential for developing novel therapies for effective cancer treatment. Pertaining to this, several phytochemicals have been identified that exhibit anti-CSC activity. However, poor pharmacokinetics prevents their clinical translation. Hence, developing phytonanomedicine can help to improve the pharmacokinetic profile of these biologically active molecules. In this review, we summarize the current state of the art of phytonanomedicine in the context of CSCs and their clinical status in cancer treatment.