HPLC-DAD-MS/MS chemical characterization and evaluation of poisoning by Vernonia rubricaulis in sheep and mice

Abstract

ABSTRACT: Vernonia rubricaulis is a plant responsible for poisoning cattle living in areas subject to flooding in the Pantanal biome of Brazil. Because V. rubricaulis causes acute hepatic necrosis and clinical signs and lesions similar to other hepatotoxic plants, its action pathways are probably similar. However, the potentially toxic components of V. rubricaulis remain unknown. Our study aims to determine the chemical profiles of aqueous and ethanolic extracts of the leaves of V. rubricaulis in the budding stage, which is known to be toxic, and in the mature stage. Experimental trials using mice and sheep investigated the presence of toxic substances in the extracts. Three groups of mice received different doses of V. rubricaulis extract. Another four groups were carried out with sheep that received: (1) aqueous extract of immature leaves, (2) aqueous extract of mature leaves, (3) ethanolic extract of mature leaves, and (4) ethanolic extract of immature leaves. Intoxication was reproduced in sheep only with the aqueous extract of V. rubricaulis buds; ethanol was not a suitable solvent for extracting toxic compounds. This finding suggests that toxic components are not present in considerable amounts in the mature plant. Swiss mice proved not to be suitable experimental models for reproducing intoxication because none of the extracts was toxic to the animals, including the one that was toxic in sheep. The chemical profile of the extracts revealed the presence of sugars, flavonoids, sphingolipids, and chlorogenic acids. Chemical profiles determined by HPLC-DAD-MS of the aqueous and ethanolic extracts of the buds and mature leaves of V. rubricaulis did not reveal compounds with known toxic potential. We demonstrated that the aqueous extraction method of V. rubricaulis was efficient at extracting toxic components from the plant’s leaves in the budding stage.

Keywords

• Hepatotoxin
• acute necrosis
• toxic plants
• cattle
• sheep
• mice
• Asteraceae
• HPLC-DAD-MS/MS