A study of the molluscicidal and larvicidal activities of Citrullus colocynthis (L.) leaf extract and its main cucurbitacins against the mollusc Galba truncatula, intermediate host of Fasciola hepatica.

Abstract

The molluscicidal and larvicidal activities of the medicinal plant Citrullus colocynthis leaf extracts and its main cucurbitacins were tested against the mollusc gastropod Galba truncatula, the intermediate host of Fasciola hepatica. Our findings proved for the first time that the molluscicidal activity was correlated with the presence of terpenoids. A significant molluscicidal value was found in the ethyl acetate extract (LC50 = 12.6 mg L-1 ). Further fractionation of this extract led to the isolation of two main compounds identified to cucurbitacin E 1 and 2-O-β-d-glucocucurbitacin E 2. Their molluscicidal activities were also investigated and they possessed close activities with LC50 = 9.55 and 10.61 mg L-1 for compounds 2 and 1, respectively. The ethyl acetate extract and both pure compounds proved the highest larvicidal activities, with a deterioration rate exceeding 89.2% (89.2-100%) and with no toxic effects against associated fauna. © 2016 Society of Chemical Industry.