Turrianes from Kermadecia rotundifolia as new acetylcholinesterase inhibitors

Four new kermadecins, together with the known kermadecins A, B and D have been isolated from the Kermadecia rotundifolia ethyl acetate bark extract. These compounds are derivatives of the (20-membered-o,-p)cyclophane skeleton and belong to the turriane family. The structures were elucidated by mass spectrometry, extensive one- and two-dimensional NMR spectroscopy and through comparison with data reported in the literature. Isokermadecin D (2) and kermadecins D and J (7 and 4) possess significant inhibitory effect on acetylcholinesterase.