Rodenticidal activity of two natural coumarines from ether extract of Citrus bergamia.

The rodenticidal activity, expressed by LD50 values of ether and petroleum ether extracts of Citrus bergamina pulp against two rat species, Rattus norvegicus (Norway rat) and Rattus rattus (roof rat) was evaluated. Based on LD50 values, ether extract was nearly 1.6 and 1.3 times more toxic to Norway rat and roof rat than ethanol respectively, while pet. ether extract was non toxic to the two rat species. From ether extract, two natural coumarines, Bergapten and Coumurrayin were isolated and tried against the two rat species as anticoagulant rodenticides. Norway rats were more susceptible to both compounds than the roof ones. A direct parallel relationship was found between the toxicity and changes in the blood picture.