Two new and two known cneorubin related diterpenes were isolated from the leaves of Guarea guidonia (Meliaceae). One of the new diterpenes has the unusual trans bicyclo[5.1.0]octane ring system. The structures were elucidated by spectral data. The analysis of the NMR spectra of the known diterpenes allowed the reassignment of their NMR data.
Guarea guidonia; Meliaceae; diterpenes; cneorubinanes; NMR data