Tropolone (Synonyms: 2-Hydroxytropone, α-Tropolone, NSC 89303, Purpurocatechol)

Tropolone is a terpene that has been found in cupressaceous tree bark and has diverse biological activities.1,2,3,4,5 It inhibits catechol O-methyltransferase (COMT; Ki = 22 μM).1 Tropolone is bacteriostatic against a panel of Gram-positive and Gram-negative bacteria (MICs = 12-82 μM) and bactericidal against A. hydrophilia and C. violaceum when used at a concentration of 20 mM.2 It is an iron chelator that inhibits iron-dependent growth of the wood rot fungus P. placenta when used at a concentration of 50 μM and P. placenta degradation of pine sapwood blocks impregnated with 5 mM tropolone.3 It inhibits LPS-induced production of nitric oxide (NO) in RAW 264.7 cells (IC50 = 12 μM).4 Tropolone (0.25 mmol/animal) reduces thyroid radioiodide uptake in rats.5 Dietary administration of tropolone induces growth retardation and hyperactivity in mice.

|1. Borchardt, R.T. Catechol 0-methyltransferase. 1. Kinetics of tropolone inhibition. J. Med. Chem. 16(4), 377-382 (1973).|2. Trust, T.J. Antibacterial activity of tropolone. Antimicrob. Agents Chemother. 7(5), 500-506 (1975).|3. Diouf, P.N., Delbarre, N., Perrin, D., et al. Influence of tropolone on Poria placenta wood degradation. Appl. Environ. Microbiol. 68(9), 4377-4382 (2002).|4. Nishishiro, M., Kurihara, T., Wakabayashi, H., et al. Effect of tropolone, azulene and azulenequinone derivatives on prostaglandin E2 production by activated macrophage-like cells. Anticancer Res. 29(1), 379-383 (2009).|5. Lee, C.P., Hegarty, M.P., and Christie, G.S. Antithyroid and antiperoxidase activity of tropolone and 3-hydroxy-4-pyrone. Chem. Biol. Interact. 27(1), 17-26 (1979).