Characterization of Diterpenes from Euphorbia prolifera and Their Antifungal Activities against Phytopathogenic Fungi.

Euphorbia prolifera is a poisonous plant belonging to the Euphorbiaceae family. In this survey on plant secondary metabolites to obtain bioactive substances for the development of new antifungal agents for agriculture, the chemical constituents of the plant E. prolifera were investigated. This procedure led to the isolation of six new and two known diterpenes. Their structures, including absolute configurations, were elucidated on the basis of extensive NMR spectroscopic data analyses and time-dependent density functional theory ECD calculations. Biological screenings revealed that these diterpenes possessed antifungal activities against three phytopathogenic fungi. The results of the phytochemical investigation further revealed the chemical components of the poisonous plant E. prolifera, and biological screenings implied the extract or bioactive diterpenes from this plant may be regarded as candidate agents of antifungal agrochemicals for crop protection products.