PW03 Plant Toxicology and Soil Interactions
Exhibit Hall
8:00 AM - Wednesday, 12 November 2003
(PW057) Fundamental biological conversions as a link between human mutagenicity and environmental toxins.
Ganguly, A.1, 1 Dominican University of California, San Rafael, CA, USA
ABSTRACT- Pyrrolizidine Alkaloids (PA's) are plants of herbaceous origin that occur in many parts of the world in unrelated botanical families and genera. The interest in these plants started in the early 60's as a result of livestock losses due to liver or lung lesions in animals feeding on pastures or humans ingesting greens contaminated with these plants. Although instances of PA poisoning have been reported all over the world in India, Sri Lanka, Germany, South Africa and Europe, the testing for pure PA's for toxicology has not been extensive. These PA's are notoriously associated with liver cancer, and yet the scientific literature on the mutagenicity tests of pure PA's reports either a non mutagenic signal or a weak mutagenicity which does not correlate to their acute hepatotoxicity. This research focuses on finding a connection between these toxic PA containing plants and mutagenic environmental nitrosamines with specificity towards liver tissues. Via a fundamental biological process, these seemingly "innocent" nitrogen containing PA's are believed to interact with NaNO2 and HCl present in foods and stomach to generate highly mutagenic/toxic nitrosamines posing a huge environmental hazard for humans and animal life. In this case study, the alkaloids in the plants are made to mimic a basic biological process and extracts are tested for mutagenicity in the Ames test. The results show a surprisingly strong mutagenic signal suggesting a metabolic conversion as the primary factor responsible for the acute hepatotoxicity observed with these plants. Thus, this case study prompts one to consider biological in vivo conversions in correlating environmental toxins to observed cytotoxicity/mutagenicity in humans and animals.
Key words: mutagenicity, alkaloids, environmental, toxins