Synthesis, biological function and evaluation of Shikonin in cancer therapy

Shikonin is a natural compound isolated from herbs and traditional medicines that have been used in a number of countries to treat various illnesses including inflammation, virus infection and cancer for centuries. Recent studies have shed light on the molecular mechanisms underlying these biological activities of Shikonin. Here we review the latest advances in our understanding of this compound class in the anti-cancer regimen. We focus on signaling pathways and cellular targets involved in the anticancer activity of Shikonin. We also briefly discuss approaches in evaluating the in vivo bioactivity and drug delivery of Shikonin in the anti-cancer treatment. Subsequently, we highlight recently developed strategies in the chemical and biogenic synthesis of Shikonin and summarize the structure-activity relationship studies of Shikonin. We anticipate that these lines of information would facilitate the functional identification and future clinical development of Shikonin and its derivatives in the combat against cancer.