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ABC’s Stefan Gafner and Colleagues Give Lecture on Botanical Ingredient Safety Evaluation for Pharmacy Students in Malawi

By ABC Staff

A torn aloe vera leaf dripping juiceIn April 2021, American Botanical Council (ABC) Chief Science Officer Stefan Gafner, PhD, and colleagues took part in a virtual lecture series on botanical ingredient safety at the University of Malawi College of Medicine in Blantyre, Malawi. The online event was attended by approximately 30 pharmacy students and faculty members and was initiated by Dallas J. Smith, PharmD, a clinical pharmacy and pharmacognosy lecturer at the college, under the auspices of the Botanical Safety Consortium (BSC) and the nonprofit Health and Environmental Sciences Institute (HESI). The lectures were part of the college’s pharmacognosy module, which teaches students about the efficacy and safety of medicinal plants and other natural ingredients and is part of the curricula for medical students in Malawi, a country in southeastern Africa that is slightly smaller than the US state of Pennsylvania and has a population of approximately 20 million people.1

Gafner opened the event with a presentation titled “Botanical Ingredient Characterization: How the Chemistry of Plants Can Provide Clues about Safety.” After explaining how environmental factors and processing can impact the chemical composition of herbal ingredients, Gafner focused on three plants with widespread use in traditional herbal medicine in Malawi: Aristolochia hockii (Aristolochiaceae), Erythroxylum emarginatum (Erythroxylaceae), and Aloe vera (Asphodelaceae). The roots of A. hockii are used to treat diabetes, measles, syphilis, and dysmenorrhea and alleviate colic in babies. A paper reporting heavy metal concentrations is the only known chemical investigation of the plant,2 and the general lack of information about the plant’s constituents, especially the presence or absence of nephrotoxic and carcinogenic aristolochic acids (which are commonly found in many species in the genus Aristolochia) was raised as a concern during the lecture. Similarly, the roots of E. emarginatum, which is used for pain relief, diarrhea, and reproductive problems in Malawi, have not been phytochemically investigated. Methylecgonidine has been found in the leaves,3 and based on the plant’s close relation to the coca plant (E. coca), Gafner recommended further research into the composition and medicinal properties of E. emarginatum. The presentation ended with a discussion on the benefits, quality assessment, and safety of aloe vera to show the differences in herbal medicine use between Malawi and the United States.

The next speaker, toxicologist Cynthia V. Rider, PhD, from the National Toxicology Program (NTP) at the US National Institute of Environmental Health Sciences (NIEHS), introduced the toxicological evaluation of botanicals. She explained basic concepts like dosage considerations, routes of exposure, acute versus chronic toxicity, pharmacokinetics, and the main target organs for herbal ingredient toxicity. Drawing from her career at NTP, Rider used several past toxicological investigations into herbal ingredients, such as non-decolorized* aloe vera whole leaf extract, ephedra (Ephedra sinica, Ephedraceae) herb, and goldenseal (Hydrastis canadensis, Ranunculaceae) root, to illustrate the rationale behind The base of an aloe vera plant, with spiky green leaves growing in a rosette shapeselecting test models, dosage, mode of administration, and duration of exposure. Of practical relevance, she noted that high doses of test substances are used in animal studies to detect statistically significant changes with a manageable sample size and to avoid missing a potential health hazard. She ended her talk by reminding students of the old Paracelsian dictum that is the basis of toxicology: “The dose makes the poison.”

The last presentation, given by Michelle R. Embry, PhD, associate director of environmental science at HESI, was a short overview of the BSC and its objectives. She noted that the BSC is a public-private partnership that resulted from a memorandum of understanding among the US Food and Drug Administration (FDA), NIEHS, and HESI. The consortium serves as a global forum for scientists from government, academia, consumer health groups, industry, and nonprofit organizations to work collaboratively on developing and integrating new methods based on sound science into routine botanical safety assessments.

The exchange with students and faculty at the end of the event highlighted not only the importance of medicinal plants as a means to heal people, but also the importance of an in-depth pharmacognosy education for pharmacists, physicians, and other health care professionals. All the presenters were impressed by the energy in the room and the interest exhibited by those who attended the presentations. Further collaboration among ABC, BSC, HESI and the College of Medicine at the University of Malawi is planned, with a proposal written by the faculty to initiate phytochemical fingerprinting and genotoxicity screening of A. hockii.

* Decolorization is a purification process that typically involves activated carbon filtration.


  1. The CIA World Fact Book website. Available at: Accessed June 8, 2021.
  2. Malaisse F, Baker AJM, Ruelle S. Diversity of plant communities and leaf heavy metal content at Luiswishi copper/cobalt mineralization, Upper Katanga, Dem. Rep. Congo. Biotechnol Agron Soc Environ. 1999;3(2):104-114.
  3. Nishiyama Y, Moriyasu M, Ichimaru M, et al. Tropane alkaloids from Erythroxylum emarginatum. J Nat Med. 2007;61(1):56-58.