Compounds inhibiting prostaglandin synthesis isolated from Ipomoea pes-caprae

The crude extract (IPA) of the plant Ipomoea pes-caprae (L.) R. Br. showed an inhibitory effect on prostaglandin synthesis in vitro. Bioassay-guided separation of the extract led to the isolation of four active compounds: 2-hydroxy-4,4,7-trimethyl-1(4H)-naphthalenone (1), (-)-mellein (2), eugenol (3), and 4-vinyl-guaiacol (4). Among the isolated compounds, 3 and 4 were the most active with IC50 values of 9.2 and 18 microM, respectively. For 1 and 2 the IC50 values were 230 and 340 microM, respectively. The influence of 1, 2, 3, and 4 on the formation of prostaglandins may partly explain a previously observed anti-inflammatory effect of the extract IPA.