Natural product-based therapeutics for the treatment of cancer stem cells: a patent review (2010 - 2013).

INTRODUCTION: Cancer stem cells (CSCs) are a subpopulation of tumor cells that possess self-renewal and tumor initiation capacity and the ability to give rise to the heterogenous lineages of cancer cells that comprise the tumor. CSCs possess numerous intrinsic mechanisms of resistance to chemotherapeutic drugs, novel tumor-targeted drugs and radiation therapy, allowing them to survive current cancer therapies and to initiate tumor recurrence and metastasis. This review presents the up-to-date natural product-based therapeutics for the treatment of CSCs. AREAS COVERED: This review gives an account of the recent therapeutic patent literature (2010 - 2013) describing the applications of natural products on CSCs. In this review, many of the therapeutic applications of natural products reported in international patents have been discussed. In addition to selected biological data, some of pharmaceutical applications are also summarized. Because of the large number of patents registered in this period relative to natural products the attention was focused, in this first part of the review, on inhibitors of six cancers. EXPERT OPINION: This patent review aims to highlight the use of natural products to treat cancer by targeting CSCs. Most of the described products are shown to have beneficial therapeutic effects and their uses for developing new formulations.