The trimeric caffeic acid derivative pulcaffeate (1) was isolated from the organic crude extract of the roots of Bourreria pulchra (Boraginaceae). The biosynthesis of 1 appears to involve an intramolecular Diels-Alder reaction between a cyclohexa-1,3-diene intermediate, generated by the oxidation of the aromatic ring of a cinnamic acid unit, and the conjugated double bond of a caffeic acid unit. The structure of the new metabolite was elucidated through a detailed analysis of its1H and13C NMR spectroscopic data. This is the first report of a trimeric metabolite occurring in B. pulchra.