Meroterpenoid dimers from Ganoderma cochlear and their cytotoxic and COX-2 inhibitory activities.

(+)- and (-)-Spirocochlealactones A-C (1-3), three pairs of new spiro meroterpenoidal dimeric enantiomers together with one known compound ganodilactone (4), were isolated from the fruiting bodies of Ganoderma cochlear. Their structures including absolute configurations were assigned by using spectroscopic methods and ECD calculations. All the isolated compounds were tested for their COX-2 inhibitory and cytotoxic activities toward human cancer lines (A549, K562, and Huh-7). The results show that all the compounds could inhibit COX-2 with IC50 values in the range of 1.29 to 3.63 μM. In addition, (+)-spirocochlealactone A and (+)-ganodilactone were found to be moderate activities against human cancer cell line A549 with the IC50 values of 7.14 and 9.47 μM, respectively.