Planta Med 2013; 79 - PK43
DOI: 10.1055/s-0033-1352303

PCR-based authentication of commercial black cohosh products – implications for reported hepatotoxicity

S Williams 1, C Howard 1, J Dixon 2, E Koch 3, D Middleton 4, A Slater 1
  • 1The Biomolecular Technology Group, Allied Health Science, De Montfort University
  • 2Leicester School of Pharmacy, De Montfort University
  • 3Preclinical Research, Dr Willmar Schwabe GmbH & Co
  • 4Schwabe Pharma UK

Black cohosh (BC) (Actaea racemosa), is a popular herbal remedy to treat side effects of the menopause. In 2011 US sales were over $10,000,000 and it ranked at number eight amongst the most popular herbs. However, its credibility is being damaged by links to reported cases of hepatotoxicity, although investigation of these reports has not been able to confirm that BC plant material is responsible. This has raised the suspicion that some cases of adverse reactions may result from substitution or adulteration with Asian Actaea species, rather than to A. racemosa. This demonstrates the need for correct identification of A. racemosa in BC products, and the exploration into potential hepatotoxicity of these different Actaea species.

We report the development of specific PCR-based assays capable of discriminating A. racemosa from potential adulterant species, particularly those associated with hepatotoxicity. A group of closely related Actaea species were chosen based on the knowledge of use as an adulterant in BC preparations. Species-specific primers were developed by aligning the DNA sequences and selecting areas of variation unique to each species. The primers were optimised for both multiplex PCR and qPCR. The product from each reaction was designed to differ in size to enable their resolution by capillary electrophoresis in the

multiplex assay, and they were shown to amplify with high efficiency in qPCR assays. These assays were used to authenticate several commercially available products. DNA was isolated from a range of different products and specific A. racemosa DNA sequences could be detected in most of the products tested. Tests are now underway to detect adulterant Actaea species in the same products.

Hepatotoxicity assays using cultured cells are being developed to test preparations from a number of Actaea species. These results will indicate the relative hepatotoxicity of BC itself and of adulterant Actaea species detected by DNA authentication assays.