During our search for bioactive compounds targeting the tubulin/ microtubules frommedicinal plants,3 we found that the extract fromthe liverwort Plagiochila fruticosa remarkably inhibited the polymerization of tubulin. Liverworts are rich sources of both terpenoids and aromatic compounds with various biological activities.4 Our efforts on identifying new agents that target tubulin resulted in the isolation of two known bis(bibenzyls), isoplagiochins A (1) and B (2).5
This paper describes effects of two bis(bibenzyls) on tubulin assembly as well as structure–activity relationship based on conformational analysis carried out by NMR spectra and computational chemistry.