Active oxygen species and structure specificity of antipsoriatic anthrones.

Abstract

AbstractTwenty‐one analogues of the antipsoriatic compound dithranol were tested for their capability to produce 1O2 and O2.‐. A correlation was found between the production of active oxygen species and the minimum structure for the antipsoriatic activity of anthrone derivatives. The ability of the anthrones to sensitize the formation of 1O2 is a function of the deprotonated hydroxyl group at C‐1 associated with the carbonyl group at C‐9 of the anthracene molecule; the CH2‐moiety at C‐10 initiates the formation of free radicals and is responsible for the production of O2.‐, which is prevented by substitution of the hydrogen atoms at C‐10. Since only the active compounds dithranol, chrysarobin, frangulaemodin‐anthrone and aloeemodin‐anthrone produce 1O2 as well as O2.‐, the therapeutic effectiveness of the anthrones appears to be due to both active oxygen species.