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

摘要

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 stillbenoid 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.