Cyclooxygenase-2 inhibitory and antioxidant compounds from the truffle Elaphomyces granulatus.

The ethanol extract of fruiting bodies of Elaphomyces granulatus, a truffle-like fungus, was evaluated for cyclooxygenase-2 (COX-2) enzyme inhibitory and antioxidant activities. Inhibition of COX-2 activity was evaluated in mouse macrophages (RAW 264.7). The extract of E. granulatus caused a 68% inhibition of COX-2 activity at 50 microg/mL. Bioassay-guided investigation led to the isolation and identification of two active compounds, syringaldehyde and syringic acid. Syringaldehyde moderately inhibited COX-2 activity with an IC(50) of 3.5 microg/mL, while syringic acid strongly inhibited COX-2 activity with an IC(50) of 0.4 microg/mL. The antioxidant activity of the extract and isolated compounds was evaluated in HL-60 cells by the DCFH-DA method. The extract of E. granulatus showed a potent antioxidant effect, with an IC(50) of 41 microg/mL. Of the pure compounds, syringic acid displayed a strong antioxidant activity, with an IC(50) of 0.7 microg/mL, while syringaldehyde showed no activity in the assay. (c) 2008 John Wiley & Sons, Ltd.