Lapachol and lapachone analogs: a journey of two decades of patent research(1997-2016).

INTRODUCTION: Lapachol (1), β-lapachone (2) and α-lapachone (3) are three well-studied natural products isolated from Tabebuia impetiginosa having most interesting chemodiversity and demonstrating diverse biological effects. Areas covered: The current review summarizes the recent and past discovery of chemotherapeutic agents based on the compounds 1-3. This review presents an overview of patents filed over the past two decades (1997 to 2016) mostly relating to the anticancer effects of these lapachol and lapachone analogues. Expert opinion: The large number of interesting patents published on the therapeutic potential of quinones 1-3 and their synthetic derivatives lends credence to the importance of these molecules. Moreover, these quinones demonstrated potent anticancer effects towards various cancer cell lines and chemical modification of these quinones have led to products displaying enhanced anticancer effects. It is noteworthy that the majority of patents published are on the anticancer effects of quinones 1-3 and their synthetic derivatives along with a limited number of additional biological effects. It is our opinion that in order to get lead compounds, there needs to be a greater focus on the elucidation of the precise mechanism of action of these compounds including SAR and in vivo studies.