Brazilian Cerrado plant (arnica) Lychnophora ericoides Mart. (Asteraceae) toxicity characterization in mice

Abstract Background Lychnophora ericoides Mart. (Asteraceae) is a Brazilian plant commonly used in folk medicine to treat pain and inflammation by topical administration. In recent years, this medicine has begun to be used orally. However, no study concerning its toxicity profile has been reported. Objective The study evaluates the potential toxicity of the ethanolic extract from leaves of the Lychnophora ericoides, through the methods of acute and sub-acute oral administration in mice. Method An acute toxicity study was performed according to the Organization for Economic Cooperation and Development protocol (OECD 423). A single extract dose of 50, 300, and 2000 mg/kg (n=3/group) was administered orally to female Swiss mice. For subacute toxicity, the protocol OECD 407 was followed. Doses of 50, 300, and 500 mg/kg (n=10/group) of the extract were administered daily to Swiss mice of both sexes for 28 days. Abnormal behavior, muscle strength, toxic symptoms, weight, and death were observed when assessing toxicity. Biochemical analysis, hematological analysis, macroscopic examination, and histopathological examination of several organs were conducted at the end of the treatment period. Results In acute and subacute toxicity, the extract did not produce mortality. The acute toxicity study revealed alterations in the behavioral test and histopathological changes in the liver, kidney, lung, and spleen. The subacute oral toxicity test showed changes in hematologic and biochemical parameters. Histopathological examination of liver, kidney, spleen, lung, and heart indicated degenerative characteristics with inflammatory infiltrates focus. Conclusion The study results suggest that oral use of Lychnophora ericoides leaves extract should be performed with caution in low doses in both single and repeated administrations.