Anticancer potential of Salvia miltiorrhiza and its tanshinones: an efficacy perspective

Abstract

Salvia miltiorrhiza Bunge (Danshen in Chinese or Tanshen in Anglicized literature) is a well-known Traditional Chinese Medicine herbal remedy for treating cardiovascular-and cerebrovascular-related disorders. To date, .40 hydrophorbic tanshinones and structurally related compounds have been isolated from the Danshen root, as have some 50 hydrophilic phenolics and other minor components. In the past 2 decades, a large quantity of literature has reported inhibitory activities of tanshinones against cancers of various organ sites in cell culture models, and in some cases with efficacy confirmation in preclinical animal cancer models. This study follows up on a 2012 review we published on the sources, pharmacokinetics, and anticancer activities of tanshinones. Here, we update on the recent progress in understanding the anticancer potential of tanshinones and derivatives and critically assess merits of these entities for future research and development. Overall, potency data from in vivo efficacy assessment experiments in preclinical models varied from nil for chemoprevention of a prostate carcinogenesis model to strong inhibition of some xenograft or allograft models. Lack of uniformity of excipients, doses, and routes of administration aside, we caution that the reviewed data should be appreciated in balance of publication bias exemplified by our own data from primary carcinogenesis study and false positivity. Novel formulations and chemical modifications had been made to improve the poor solubility and bioavailability of tanshinones. Human clinical studies so far dealt with case reports of tanshinone IIA use and small-scale trials on Danshen-containing formulas with chemotherapy for cancers of multiple organ sites in People's Republic of China. Available human data are not sufficient for supporting any anticancer indication of tanshinones.