Synthesis and PGE2 inhibitory activity of 5,7-dihydroxyflavones and their O-methylated flavone analogs

5,7-Dihydroxyflavones and their O-methylated flavone analogs were prepared and evaluated their anti-inflammatory activity to decipher the structure-activity relationships. Most of the analogs were achieved from 2,4,6-trihydroxyacetophenone in 4 steps. 5, 7-Dihydroxy-4'-methoxyflavone (4c) and 7-hydroxy4',5-dimethoxyflavone(6c) were prepared following a different synthetic pathway. Among the synthetic flavones tested, 5-hydroxy-7-methoxyflavone analogs (3a-3e) showed moderate inhibitory activities of PGE(2) production from LPS-induced RAW 264.7 cells.