A novel bridged stilbenoid trimer and four highly condensed stilbenoid oligomers in Vatica rassak

Abstract Vaticanol G ( 1 ) and vaticaside D ( 2 ) isolated from stem bark of Vatica rassak (Dipterocarpaceae) were the first instance of stilbenoid trimers with an unusual tribenzobicyclo[3.3.2]decatriene system. Vaticanols D ( 3 ) and H ( 4 )–J ( 6 ) were elucidated to be a stilbenoid hexamer or heptamer containing a structurally identical trimeric unit. Their structures and the relative configurations were established on the basis of 2D NMR spectroscopy. The hexamers ( 3 , 4 and 5 ) and the heptemer ( 6 ) showed cytotoxicity against KB cells.