We rested whether Ambroxol, a drug which stimulates the release of sur
factant by pneumocytes type II, may also possess antioxidant propertie
s. To assess the reactivity of Ambroxol with reactive oxygen species,
we analysed its ability to decompose hydrogen peroxide (H2O2) and to i
nhibit the superoxide (O-2(.-))-dependent autooxidation of pyrogallol,
hydroxyl radical ((OH)-O-.)-mediated deoxyribose oxidation, and hypoc
hlorous acid (HClO)-induced chlorination of monochlorodimedon. Ambroxo
l was found to be a sufficient scavenger of HClO and (OH)-O-. and also
revealed the capacity to decompose H2O2 At concentrations of 25 and 7
0 mu M, it inhibited HClO-induced chlorination of monochlorodimedon by
22 +/- 13 and 59 +/- 14%, respectively. Similarly, at concentrations
of 1, 2, and 10 mM, Ambroxol decreased (OH)-O-.-mediated deoxyribose o
xidation by 47 +/- 11, 75 +/- 9, and 89 +/- 4%. In addition, at concen
trations of 1 to 5 mM, it completely protected linoleic acid from (OH)
-O-.-induced peroxidative damage. Ambroxol had a weak effect on O-2(.-
)-dependent autooxidation of pyrogallol. Our results indicate that Amb
roxol has antioxidant activity, which may have clinical significance i
n protecting lung tissue from oxidant-induced injury.