Potential for identifying plant-based toxins on San hunter-gatherer arrowheads

Madelien Wooding; Justin Bradfield; Vinesh Maharaj; Dwayne Koot; Lyn Wadley; Linda Prinsloo; Marlize Lombard

doi:10.17159/sajs.2017/20160210

Authors

Madelien Wooding Department of Chemistry, University of Pretoria, Pretoria, South Africa http://orcid.org/0000-0003-3869-7467
Justin Bradfield 1. Department of Anthropology and Development Studies, University of Johannesburg, Johannesburg, South Africa 2. Evolutionary Studies Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa http://orcid.org/0000-0002-6139-6227
Vinesh Maharaj Department of Chemistry, University of Pretoria, Pretoria, South Africa http://orcid.org/0000-0002-6512-304X
Dwayne Koot Department of Chemistry, University of Pretoria, Pretoria, South Africa
Lyn Wadley Evolutionary Studies Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa http://orcid.org/0000-0003-0053-0813
Linda Prinsloo 1. Department of Physics, University of Pretoria, Pretoria, South Africa 2. Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Sydney, Australia http://orcid.org/0000-0001-6465-8467
Marlize Lombard Department of Anthropology and Development Studies, University of Johannesburg, Johannesburg, South Africa http://orcid.org/0000-0002-0675-0414

DOI:

https://doi.org/10.17159/sajs.2017/20160210

Keywords:

San hunting poisons, southern Africa, liquid chromatography, accurate mass-mass spectrometry, archaeological analysis

Abstract

The antiquity of the use of hunting poisons has received much attention in recent years. In this paper we present the results of a pilot study designed to detect the presence of organic compounds, typically of less than 1200 Da, from poisonous plants that may have been used as hunting poisons in the past. We used ultra-performance liquid chromatography connected to a Synapt G2 high-resolution MS-QTOF mass spectrometer (UPLC-QTOF-MS) to provisionally identify plant-based toxins present in (1) extracts of fresh plant material, (2) a blind control recipe consisting of three plant ingredients and (3) a Hei||om arrow poison of unknown ingredients. Although not all expected toxic compounds were identified, those that were identified compared favourably with those reported in the literature and confirmed through databases, specifically the Dictionary of Natural Products and ChemSpider. MS/MS fragmentation patterns and accurate mass were used for tentative identification of compounds because archaeological residues usually contain insufficient material for unambiguous identification using nuclear magnetic resonance. We highlight the potential of this method for accurately identifying plant-based toxins present on archaeological artefacts and unique (albeit non-toxic) chemical markers that may allow one to infer the presence of toxic plant ingredients in arrow poisons. Any chemical study of archaeological material should consider the unique environmental degradative factors and be sensitive to the oxidative by-products of toxic compounds.

Significance: