Analogues of anthracene, phenanthrene, and benzoflavone inhibit prostaglandin biosynthesis by cells in culture.

Prostaglandin production by methylcholanthrene-transformed 3T3 mouse fibroblasts (MC5-5), human normal fibroblasts (D550), and canine kidney (MDCK) cells was inhibited by several analogues of anthracene, phenanthrene, and benzoflavone. Among the most effective inhibitors of MC5-5's prostaglandin production were anthracene (ID50=1.7 micrometer), 9,10-diaminophenanthrene (ID50=0.48 micrometer), and 7,8-benzoflavone (ID50=0.55 micrometer). Under identical conditions, the ID50's for indomethacin and aspirin were 0.049 and 8.9 micrometer respectively. Production of radioactive prostaglandins by MC5-5 cells from tritiated phospholipids was blocked by 7,8-benzoflavone, but not the release of radioactive arachidonic acid.