John Arnason

Chemical ecology; Ethnopharmacology and medical plants

 

Welcome

Rank: Full-time Professor

Department: Biology

Teaching field: Chemical ecology

Education

  • BSc Carleton University (1970)
  • PhD Carleton University (1976)

Keywords: Physiology and biochemistry, ethnobotany, phytochemistry,natural health products, chemical ecology

Current research interests:

1. Chemical ecology

Co-evolution of plants and their pests has led to the diversification of plants and insects as well as the biochemical defenses of plants, known as secondary metabolites or phytochemicals. Our research group has studied in detail several types of phytochemical defenses in plant families including light activated phytochemicals of the sunflower family, insect antifeedant defenses of the mahogany family, neurotoxins and synergists of the pepper family, and dehydrodiferulate dimers in cereals. The adaptive response of insects and other pests to these defenses and their applications have been another focus of this research. Currently, our discovery program is studying rare plant families of the neotropics in collaboration with Costa Rican researchers in order to discover new and potentially useful natural plant products.

 2. Ethnopharmacology and medicinal plants

Knowledge of biologically active medicinal plant species in world floras is perhaps greatest among traditional healers. We are collaborating with groups of healers in various locations to better record and understand their pharmacopoeias, the biological activity of their plants and the cultural context of their traditional medicine. The use of antimalarial and antifungal plants is a focus of this research.

Legislation enacted this year allows therapeutic use of botanical drugs in Canada yet our native medicinal flora remains largely unstudied. We are studying some native species of medicinal plants in detail for the first time to characterize their mode of action, to improve quality assurance, safety and efficacy as well as evaluate the potential of each species to produce harmful drug interactions. Our group is investigating new botanical drugs for the treatment of anxiety, to treat preventable complications in diabetes and to combat the problem of antibiotic resistance in collaborative projects. The newly constructed phytochemical facility at the University of Ottawa is used to identify and quantify active principles in the plants and in animal models using HPLC/MS. The facility allows study of variation in the phytochemical profiles of native germplasm, to develop cleaner and solvent free extracts through supercritical carbon dioxide extraction and with specific groups of compounds for bioassay evaluation. Advanced evaluation of selected species as antivirals and antimicrobials is being undertaken using DNA and proteomic array methods.