Nordihydroguaiaretic acid is a potent in vitro scavenger of peroxynitrite, singlet oxygen, hydroxyl radical, superoxide anion and hypochlorous acid and prevents in vivo ozone-induced tyrosine nitration in lungs

The antioxidant nordihydroguaiaretic acid ( NDGA) has recently become well known as a putative anticancer drug. In this paper, it was evaluated the in vitro peroxynitrite (ONOO-), singlet oxygen (O-1(2)), hydroxyl radical (OHcenter dot), hydrogen peroxide (H2O2), superoxide anion (O-2(center dot-)) and hypochlorous acid (HOCl) scavenging capacity of NDGA. It was found that NDGA scavenges: ( a) ONOO- (IC50 = 4 +/- 0.94 mu M) as efficiently as uric acid; (b) O-1(2) (IC50 = 151 +/- 20 mu M) more efficiently than dimethyl thiourea, lipoic acid, N-acetyl-cysteine and glutathione; (c) OHcenter dot (IC50 = 0.15 +/- 0.02 mu M) more efficiently than dimethyl thiourea, uric acid, trolox, dimethyl sulfoxide and mannitol, (d) O-2(center dot-) (IC50 = 15 +/- 1 mu M) more efficiently than N-acetyl-cysteine, glutathione, tempol and deferoxamine and (e) HOCl (IC50 = 622 +/- 42 mu M) as efficiently as lipoic acid and N-acetyl-cysteine. NDGA was unable to scavenge H2O2. In an in vivo study in rats, NDGA was able to prevent ozone-induced tyrosine nitration in lungs. It is concluded that NDGA is a potent in vitro scavenger of ONOO-, O-1(2), OHcenter dot, O-2(center dot-) and HOCl and is able to prevent lung tyrosine nitration in vivo.