From the aerial parts of Oyedaea verbesinoides nine ent-kauranes and a sesquiterpene were isolated. ent-9α-Hydroxy-kaur-16-en-19-oic acid, ent-15β-tigloyloxy-9α-hydroxy-kaur-16-en-19-oic acid, ent-15β-angeloyloxy-9α-hydroxy-kaur-16-en-19-oic acid, ent-16α-hydroxykaurane and 1α-angeloyloxy-carotol are new for the genus or the species and ent-15β-angeloyloxy-7α,9α-dihydroxy-kaur-16-en-19-oic acid is reported for the first time. Structure elucidation was based on one and two dimensional NMR as well as ESI and CI-MS analysis. Some diterpenes were proven to exhibit inhibitory effects on smooth muscle contraction on rat aorta.
Isolation and structure elucidation of a new ent-kaurene based on NMR and mass spectra data are reported. Further ent-kauranes were tested for their spasmolytic effects on rat aorta.