Isolation and identification of L-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and L-1-methyl-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline from seeds and callus of S. hassjoo are described. Administration of [β-¹⁴C]-labelled DOPA to a callus culture of this legume resulted in the incorporation of radioactivity into L-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, L-1-methyl-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and stizolobic acid, which was confirmed by constant specific radioactivity after co-crystallization with authentic samples of each compound. A detailed chemical investigation of extracts of the bark, leaf and timber of Horsfieldia iryaghedhi collected in Sri Lanka, led to the isolation of (+)-asarinin, dodecanoylphloroglucinol and (-)-dihydrocubebin.