DNA sequencing and metabolomics: new approaches to the forensic assessment of herbal therapeutic agents

The role and frequency that herbal therapeutic agents play in unexpected deaths remains unclear. Herbal agents may be directly toxic in their own right, or they may act synergistically with other herbal materials, or with prescribed pharmaceutical agents. Herbal therapies are also known to sometimes contain toxic agents such as herbicides or heavy metals, or to have been adulterated with standard drugs to enhance their efficacy [1]. In the medicolegal arena the consumption of drugs that may be contraindicated in certain conditions may not be apparent at the time of autopsy, such as when steroids or non-steroidal antiinflammatory agents have been unknowingly taken by an individual with active peptic ulcer disease. Substitution of one plant for another, whether because of financial considerations or from a genuine mistake in plant identification, compounds the complexities associated with attempting to determine whether a herbal preparation has contributed to, or caused, illness or death. Thus, when compared to the assessment of prescribed medications in a standard forensic autopsy, the evaluation of the role of herbal preparations in a death is problematic [2, 3]. Death scene examiners may not document herbal preparations, as they may be considered to be ‘‘natural’’ products and therefore not likely to cause any health problems. Even if herbal medications are recorded at a death scene, there is no guarantee that the ingredients and dosages listed on the container (if this information is available) are a true reflection of the composition of the contained preparation. As standard preparations come as powders, pill or liquids, standard taxonomic classification of herbs by morphology is not possible. Finally, due to the complex organic molecules present and the blending of a number of plants, searching for active organic ingredients in forensic toxicology laboratories may resemble the time honored search for the ‘‘needle in haystack’’ [4]. Fortunately technology is now available which may assist in focusing the search for these elusive active organic agents. Two recent papers [5, 6] show how DNA sequencing can be used to identify materials in herbal medicines that would otherwise be potentially difficult to analyze. In particular, Coghlan et al.’s [5] use of next generation DNA sequencing (NGS) demonstrates how sophisticated analyses of samples, including complex mixtures unable to be evaluated effectively by previous techniques, can be rapidly screened. NGS analysis of herbal medications confiscated at a death scene may provide valuable data that can then be compared to either in-house databases or to larger collections such as the NIH genetic sequence database, GenBank (http://www.ncbi.nlm.nih. gov/genbank/). Although a potential difficulty with external databases involves the accuracy with which entries have been checked prior to uploading, they may, along with smaller databases, be extremely useful in matching the pattern of a DNA sequence to that of known plants. Thus, modern DNA sequencing can rapidly provide a genetic audit of large numbers of cases that can be matched against established standards to focus the search for ingredients [5] such as toxic plants and/or potential allergens. R. W. Byard (&) I. Musgrave C. Hoban School of Medical Sciences, Level 3 Medical School North Building, The University of Adelaide, Frome Road, Adelaide, SA 5005, Australia e-mail: roger.byard@sa.gov.au