There is an increasing recognition of the deep time co-evolutionary relationship between humans and many psychoactive and medicinal plants, yet much remains to be learned about their past use. Researchers aim to understand the complex evolutionary processes through which societies and individuals interacted with ancient drugs including tobacco, cannabis, caffeinated teas, coffee, chocolate, and opiates. Few adults today have not used or been impacted by one or more of these intoxicants, many of which have in recent times been refined into incredibly potent and addictive substances, with global health consequences. Archaeology offers a deep-time perspective into plant domestication, coupled human-plant interactions, and addiction and drug use by people, who used an array of plants not only as food but also for social, ceremonial, recreational, and medicinal reasons. Chemical residue analysis of alkaloid biomarkers in ancient materials offers a novel means of approaching these issues; recent studies have produced compelling results demonstrating the global scale and deep time use of intoxicant plants. However, major challenges remain, particularly in terms of baseline experimental method development in controlled laboratory settings. Washington State University (WSU) scientists Dr. Shannon Tushingham and Dr. David Gang will undertake research designed to expand frontiers in the biomolecular archaeology of psychoactive plants through a 3-year program of hypothesis testing and experimentation in controlled laboratory settings aimed at developing rigorous methods and cutting-edge technologies that will expand understanding of past use of psychoactives among global societies. Analytical methods include liquid and gas chromatography-time of flight mass spectrometry (LC-TOFMS and GC-TOFMS), Matrix-assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS), and metabolomics research tools to chemically fingerprint key drug plants and test assumptions concerning their use in the past.

The WSU team focuses on two exciting research avenues: (1) ancient metabolomics, which employs powerful metabolomic profiling tools to evaluate the complete chemical fingerprint of plants and ancient residues, with the goal of discriminating plants to the species level, and (2) dental calculus studies, directed at refining identification of intoxicant compounds in human dental calculus (mineralized plaque), which permits identification of drug use of substances including tobacco, cannabis, and opioids to the individual level. Improved dental calculus methods will provide researchers the capability to ask anthropologically significant questions about intoxicant use by individuals of varied circumstances and societal groups (e.g., use patterns by age, gender, status, health categories) and previously "invisible" users (i.e., those not buried with artifacts indicating use such as pipes), as well as effects on oral health, past and present. Hypothesis testing involves method-building experiments with laboratory-produced artifacts (e.g., ceramic pots brewed with cacao, cassina tea, etc.) and modern dental calculus (obtained through a collaboration with the University of Washington Department of Periodontics), as well as a series of method validation/ directed pilot studies on archaeological artifacts. Undergraduate and graduate students are involved in every stage and gain valuable archaeometric skills. Broader impacts are expanded through interdisciplinary educational, public dissemination, and collaborative projects, and involve public displays/ presentations, research partnerships with Tribal communities, and educational and outreach projects.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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Washington State University
United States
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