THE ANTIOXIDATIVE ACTIVITY OF THE MUCOREGULATORY AGENTS - AMBROXOL, BROMHEXINE AND N-ACETYL-L-CYSTEINE - A PULSE-RADIOLYSIS STUDY

Ambroxol and bromhexine are shown to be scavengers of both superoxide and hydroxyl radicals as determined by pulse radiolysis experiments. T he dismutation of superoxide was accelerated 3-fold by bromhexine and 2.5-fold by ambroxol over the rate of spontaneous dismutation. The rea ction constants of hydroxyl radicals with bromhexine and ambroxol were determined by competition kinetics to be 1.58 +/- 0.15 x 10(10) M(-1) s(-1) and 1.04 +/- 0.1 x 10(10) M(-1)s(-1), respectively. N-acetyl-L-c ysteine also reacted with hydroxyl radicals (1.28 +/- 0.14 x 10(10) M( -1)s(-1)) but not with superoxide radical. These effects may be clinic ally relevant in the treatment of oxidant-associated lung damage induc ed by inflammatory agents and/or environmental pollutants.