Toxicity of Crepis lacera in grazing ruminants

Background: Crepis lacera is a plant from the Asteraceae family that is common in the Mediterranean region. Farmers believe that this plant may be deadly to small ruminants in areas of southern Italy. However, scientific evidence is lacking, and no proof exists that C. lacera is toxic to ruminants. Necropsies conducted on four sheep revealed lesions in their livers and kidneys. Results: In the current study, we described sheep poisoning and isolated secondary metabolites from Crepis lacera to assess the metabolites' biological activity both in vitro and in vivo. Phytochemical study of the aerial portions of Crepis lacera led to the isolation of five sesquiterpene lactones and two phenolic compounds. Cellular viability was evaluated in cell cultures of the bovine kidney cell line Madin Darby Bovine Kidney (MDBK) after incubation with phytochemicals. Our results showed that three sesquiterpene lactones, 8-epidesacylcynaropicrin-3-O-beta-glucopyranoside (2), 8-epigrosheimin (3), and 8-beta-hydroxydehydrozaluzanin C (4), were cytotoxic after 48 h of incubation. In addition, in the in vivo study, animals that received 1 mg/kg body weight (bw) of Crepis lacera extract and were then sacrificed after 48 h showed significant lesions in their liver, lungs and kidneys. These lesions were also found in rats that received 2 mg/kg bw of the same extract and sacrificed after 24 and 48 h. Conclusions: These results validate the hypothesis that C. lacera is potentially dangerous when ingested in large quantities by grazing small domestic ruminants. Further studies are necessary to clarify the molecular mechanisms of Crepis spp. toxicity in animals.