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United States Department of Agriculture

Agricultural Research Service

Research Project: THE TOXICITY OF PYRROLIZIDINE ALKALOID-CONTAINING PLANTS AND OTHER HEPATOTOXIC AND NEUROTOXIC PLANTS Title: Baccharis pteronioides toxicity

Authors
item Stegelmeier, Bryan
item Sani, Y -
item Pfister, James

Submitted to: Poisoning by Plants, Mycotoxins, and Related Toxins
Publication Type: Book / Chapter
Publication Acceptance Date: January 8, 2010
Publication Date: May 1, 2011
Citation: Stegelmeier, B.L., Sani, Y., Pfister, J.A. 2011. Baccharis pteronioides toxicity. In: Riet-Correa, F., Pfister, J., Schild, A.L., Wierenga, T., editors. Poisoning by Plants, Mycotoxins, and Related Toxins. Cambridge, MA. CAB International. 72:433-6.

Interpretive Summary: Baccharis pteronioides DC. occasionally poisons livestock in the southwestern United States. Various toxins including diterpenic lactones, sesquiterpenes , flavonoids, saponins, tannins, phenolic compounds and essential oils have been isolated and described from several Baccharis species. However, none has been proven to be the cause of B. pteronioides toxicity. Reports suggest that poisoning occurs in drought when cattle that are forced to eat Baccharis. Some poisonings can be severe with cattle deaths as high as 40%. Diagnosis of poisoning has also been challenging as the post mortem changes are non-specific and easily confused with other infectious diseases. Shortly after an incidence of B. pteronioides intoxication, plant materials were collected for feeding trials and chemical evaluation. Forty-eight, 8-week-old Syrian hamsters were dosed with 0, 50, 100 and 200 mg B. pteronioides for 10 days. After the treatment period, the hamsters were necropsied; blood and tissues were collected and evaluated. The hamsters treated with 200 mg and several of the 100 mg animals developed anorexia and diarrhea. These animals had multiple bloody infarcts in the liver and kidney with severe bloody enteritis. Histologically the poisoned animals had severe vasculitis with vascular thrombosis of hepatic and renal vessels. Many glomerular capillaries contained fibrin thrombi. The superficial intestinal and colonic mucosa was necrotic with extensive hemorrhage and proliferation of luminal bacteria. Lower dose animals had mild hepatocellular swelling with proliferation of intestinal and gastric bacteria and yeast. These findings indicate that at high doses, B. pteronioides is toxic to hamsters and produces lesions that are very similar to bacterial endotoxin produced vasculitis and infarction. Additional research is needed to identify the toxin, determine the conditions of poisoning and toxic dose and define the mechanism of toxicity.

Technical Abstract: Baccharis pteronioides DC. occasionally poisons livestock in the southwestern United States. Various toxins including diterpenic lactones, sesquiterpenes , flavonoids, saponins, tannins, phenolic compounds and essential oils have been isolated and described from several Baccharis species, but none has been proven to be the cause of B. pteronioides toxicity. Reports suggest that poisoning occurs in drought when cattle that are forced to eat Baccharis. Some poisonings can be severe with mortalities as high as 40%. Diagnosis of poisoning has also been challenging as the post mortem changes are non-specific and easily confused with other infectious diseases. Shortly after an incidence of B. pteronioides intoxication, plant materials were collected for feeding trials and chemical evaluation. Forty-eight, 8-week-old Syrian hamsters were randomly divided into 4 groups and dosed with 0, 50, 100 and 200 mg B. pteronioides for 10 days. After dosing, the hamsters were necropsied; sera were analyzed biochemically; and tissues were collected and evaluated histologically. The hamsters treated with 200 mg and several of the 100 mg animals developed anorexia and diarrhea. These animals had multiple hemorrhagic infarcts in the liver and kidney with severe hemorrhagic enteritis. Histologically the poisoned animals had severe necrotizing vasculitis with vascular thrombosis of hepatic and renal vessels. Many glomerular capillaries contained fibrin thrombi. The superficial intestinal and colonic mucosa was necrotic with extensive hemorrhage and proliferation of luminal bacteria. Lower dose animals had mild hepatocellular swelling with proliferation of intestinal and gastric bacteria and yeast. These findings indicate that at high doses, B. pteronioides is toxic to hamsters and produces lesions that are very similar to bacterial endotoxin produced vasculitis and infarction. Additional research is needed to identify the toxin, determine the conditions of poisoning and toxic dose and define the mechanism of toxicity.

Last Modified: 12/18/2014
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