Pharmacognosy of black cohosh: the phytochemical and biological profile of a major botanical dietary supplement.

Abstract

The ethnobotanical, Black Cohosh, a preparation from the roots/rhizomes of Actaea racemosa, has been the subject of extensive investigations. Despite the fact that sales figures place it among the top ten U.S. dietary supplements, the mechanisms of its amelioration of the adverse effects of menstruation and menopause remain largely undefined. The plant is a prodigious “factory” of complex secondary metabolites, with almost 50 cycloartane triterpenes, over 70 alkaloids, and 11 phenolic acids characterized so far, and this chapter discusses the chemistry of the A. racemosa secondary metabolome in detail. While numerous in vitro and in vivo pharmacological and biological studies attribute diverse specific biochemical effects to individual metabolites or defined extracts, an adequate explanation of potencies and drug(-like) concentrations is still lacking. As many of the effects may play a role in the alleviation of menopausal symptoms, the possibility exists that the overall effect may be the result of a combination of both multiple bioactive principles and several synergistic interactions. On careful analysis, a purported hepatotoxicity risk raised has been relegated to “a possible rare idiosyncratic reaction”. More than 50 clinical studies defy definitive analysis, other than confirming that the material is safe, in part because of poor study design and differences in preparations used. The global literature on Black Cohosh is almost unanimous in a call for larger, more well-designed clinical studies, and recent advances in the understanding of the phytoconstituents justify a more thorough secondary metabolomics analysis of this interesting North American plant.