Kaurene diterpenes from Mikania vitifolia

From the aerial parts of Mikania vitifolia three new ent-kaurane diterpenes, ent-7α-cinnamoyloxy-15β-hydroxy-kaur-16-en-19-oic acid, ent-15β-cinnamoyloxy-7α-hydroxy-kaur-16-en-19-oic acid and ent-15β-hydroxy-7α-(E)-lachnophylloyloxy-kaur-16-en-19-oic acid were isolated together with the known ent-kauranesent-kaur-16-en-19-oic acid, ent-kaur-16-en-19-ol, ent-15β-hydroxy-kaur-16-en-19-oic acid and ent-15α-cinnamoyloxy-kaur-16-en-19-oic acid. The structures were established by mass spectrometry, 1H NMR and partly 13C NMR spectroscopy. Isolation of the new ent-7α-cinnamoyloxy-15β-hydroxy-kaur-16-en-19-oic acid (1), ent-15β-cinnamoyloxy-7α-hydroxy-kaur-16-en-19-oic acid (2) and ent-15β-hydroxy-7α-(E)-lachnophylloyloxy-kaur-16-en-19-oic acid (3) as well as further ent-kauranes.Institut für Pharmazeutische Chemie//IPC/AlemaniaUniversität Düsseldorf//HHU/AlemaniaUniversität Freiburg//ALU/AlemaniaInstitut für Pharmazeutische Biologie//IPB/AlemaniaInstituto Nacional de Biodiversidad//INBio/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic