NEW ACETYLENES ISOLATED FROM THE BARK OF HEISTERIA-ACUMINATA

Five new linear acetylenic compounds, namely, pentadeca-6,8,10-triynoi c acid (1), octadeca-8,10,12-triynoic acid (2), trans-pentadec-10-en-6 ,8-diynoic acid (3), cis-hexadec-11-en-7,9-diynoic acid (4), and cis-o ctadec-12-en-7,9-diynoic acid (5), were isolated from the bark of Heis teria acuminata by bioassay-guided fractionation, using cyclooxygenase (COX) and 5-lipoxygenase (5-LO) assays as models for antiinflammatory activity. The structures of compounds 1-5 were established by NMR, MS , IR, and Raman spectroscopy. These isolated compounds were found to b e potent inhibitors of COX. Compounds 4 and 5 were the most potent inh ibitors of 5-LO, whereas the other compounds only showed a weak inhibi tion at the same concentration.