Antipruritic effects of 1,4-naphthoquinones and related compounds.

The antipruritic effects of orally administered 1,4-naphthoquinone derivatives and related compounds on compound 48/80-induced scratching behavior in mice were studied. 2-Hydroxy-3-(2-hydroxyethyl)-1,4-naphthoquinone, ferulic acid, 2,2'-methylenebis(3-hydroxy-1,4-naphthoquinone), and 2,2'-ethylidenebis(3-hydroxy-1,4-naphthoquinone) (impatienol) all exhibited significant antipruritic activity. However, 2-methoxy-3-(2-hydroxyethyl)-1,4-naphthoquinone (balsaquinone), which was isolated from a natural source for the first time, did not show any activity. The present results indicate that these compounds are promising for treating allergic diseases with chronic and severe pruritus.