Isolation and pesticide activity of daphnanes of Lasiosiphon kraussianus

The significance of rodent damage to health, agricultural production or structures has come to be widely recognised as economically very important (1). Plants offer an excellent source of biologically active natural products. The most important botanical rodenticides are scilliroside (2), reserpine (3) and strychnine (4). The natural products used as rodenticides per se are all acute poisons until the discovery of the anticoagulant rodenticides in the early 1950s (4). The spread of rat resistance to anticoagulant rodenticides limited the effectiveness of rat control (5). Therefore, and beside resistance management (6), the development of new natural products, to be directly used or as lead for synthesis, will be the most practicable method to solve most rat problems. The family Thymelaeaceae is distributed throughout the tropical and temperate parts of the world. The toxicity of plants in the Thymelaeaceae, and the compounds isolated from plants in this family were summarized (7). On the other hand, some pharmacological investigations have been carried out in this plant roots (8-10). A detailed description of Lasiosiphon kraussianus (Mesin) had been reported (11). The leaves of this plant were reported to be poisonous when fed to livestock (12). Literature survey showed no reference to natural products that have been isolated from the leaves of this plant and thus far, no pesticidal investigation has been reported. Depending on that, the present work deals with the isolation and structure elucidation of a diterpenoid having daphnane skeleton, Kraussianin, exhibiting potent acute activity against mice Mus musculus. It is worth noting that, Kraussianin is also known as a potent antileukemic compound (13).