Submitted to: Toxins in Food
Publication Type: Book / Chapter
Publication Acceptance Date: December 15, 2004
Publication Date: December 2, 2004
Citation: Panter, K.E. 2005. Natural toxins of plant origin. Toxins in Food. Interpretive Summary: While poisonous plants on grazing lands have a significant impact on livestock production throughout the world, the natural toxins (secondary metabolites) in the plant may have multiple and diverse functions, not only for the plant world but also for the benefit of mankind. Many current pharmaceuticals have been chemically optimized from natural toxins of plant origin. New plant compounds and familiar compounds with renewed interest, e.g., nutraceuticals, herbal preparations, nutritional supplements, etc. are increasingly finding their value in human nutrition and health. Given the significance of plant compounds to people and animals, the primary function of secondary metabolites in plants remains a topic of extensive discussion and research. It has been argued for decades that many of these compounds serve as a defense mechanism to protect plants against herbivory, predation or disease (reviewed in Wink, 1999). Secondary compounds can protect a plant in various ways: by imparting bitterness or causing discomfort or some other negative cue to inhibit herbivory, or they may be overtly toxic thus killing or debilitating the predator or causing an inherent aversion to the plant. Secondary compounds produced by plants may have other significant survival roles, such as signals to attract insects, birds, or other animals to enhance pollination or seed dispersal. In addition to any potential functions, secondary compounds may concomitantly serve a physiologic function, such as protection against ultraviolet (UV) light or frost, or provide a function in nitrogen transport and storage. In several instances, compounds can serve multiple functions in the same plant. Anthocyanins or monoterpenes can be insect
Technical Abstract: Poisonous Plants and the natural toxins therefrom cause significant economic losses to livestock industries throughout the world. Using 1989 figures, it was estimated that poisonous plants cause losses of over #340 million annually to the livestock industry in the seventeen western states of the U.S. (Nielsen and James, 1992; Frandsen and Boe, 1991). Applying a 3% annual inflation rate, this figure would have exceeded $500 million in 2003. This estimate only includes losses caused by the deaths of cattle and sheep and does not include increased management costs, lost forage and grazing opportunities, additional health care, etc. Other livestock species and wildlife are also affected by poisonous plants, further increasing losses. As a recent illustration, in the spring of 1997 over 4000 calves either died or were destroyed because of lupine-induced ‘crooked calf syndrome’ in a single county of eastern Washington state (Panter et al., 1999). The direct losses to ranchers in this area exceeded $1.7 million (calf losses only). This figure did not take into account losses due to cow deaths, extensive culling of cows without calves, heifer replacement costs, increased cost of veterinary care, increased management, etc. Furthermore, this dollar amount does not take into account the economic impact on other businesses in the area supported by the cattle industry. The overall cost of poisonous plants to rural communities and especially the livestock industry, is enormous.