Characterization of diterpenoids from Caesalpinia decapetala and their anti-TMV activities

Caesalpinia decapetala is a versatile medicinal plant belonging to the Fabaceae plant family. In our survey on plant secondary metabolites to obtain bioactive substances for the development of new agricultural anti-TMV agents, the chemical constituents of C. decapetala were investigated. This investigation led to the isolation of three new and ten known diterpenoids. Their structures including absolute configurations were elucidated based on the extensive NMR spectroscopic data analyses and the time-dependent density functional theory calculations. The following biological screenings revealed that most of these diterpenoids possessed anti-TMV activities.