| Popis: |
Ten new neolignans including the 2′-oxo-8.1′-lignans cymosalignans A (1a), B (2), and C (3), an 8.O.6′-neolignan (4a), ococymosin (5a), didymochlaenone C (6a) and the bicyclo[3.2.1]octanoids 7–10 were isolated along with the known compounds 3,4,5,3′,5′-pentamethoxy-1′-allyl-8.O.4′-neolignan, 3,4,5,3′-tetramethoxy-1′-allyl-8.O.4′-neolignan, didymochlaenone B, virologin B, ocobullenone and the unusual 2′-oxo-8.1′ –lignan sibyllenone from the stems or bark of the Madagascan plant Ocotea cymosa (Lauraceae). The new 8.O.6′-neolignan 4a, dihydrobenzofuranoid 5a, and the bicyclo[3.2.1]octanoid 7a had weak in vitro activity against Aedes aegypti, while the new compounds 5a, 7a, 8 and 10a and the known virolongin B (4b) and ocobullenone (10b) had antiplasmodial activity. We report herein the structure elucidation of the new compounds on the basis of spectroscopic evidence, including 1- and 2-D NMR spectra, Electronic Circular Dichroism (ECD), and mass spectrometry, and the biological activities of the new and known compounds. |
