Therapeutic potential of boswellic acids: a patent review (1990-2015)

Boswellic acids (BAs), a group of pentacyclic triterpenoids, have demonstrated very interesting biological properties that resulted in a number of protocols being developed for their synthesis. During the last twenty-five years (1990-2015), numerous BAs have been prepared. Both natural BAs and their synthetic derivatives can be used to treat various cancers as well as inflammatory diseases. Areas covered: This review covers patents on therapeutic activities of natural BAs and their synthetic derivatives published in last twenty-five years (1990-2015). Only BA patents to treat cancer and inflammation are available. A discussion about structure-activity relationships (SAR) of these analogs is also included. Expert opinion: BAs possess excellent anticancer and anti-inflammatory properties. A large number of BAs and their analogues have been prepared through modification at the C₃-OH and C₂₄-CO₂H functional groups. Most importantly, the C-24 amide and amino derivatives demonstrated increased anticancer and anti-inflammatory activity compared with other BA derivatives. Furthermore, BAs have the potential to form conjugates with other anticancer drugs that will synergistically enhance their anticancer effects; and we believe that in order to get lead compounds, there needs to be a greater focus on the synthesis of halo derivatives of BAs.