Evaluation of quenching effects of non-water-soluble and water-soluble rosemary extracts against active oxygen species by chemiluminescent assay

The quenching effects of non-water-soluble (NWS) and water-soluble (WS) rosemary extracts against active oxygen species were investigated by a chemiluminescent assay. The EC50 values of the NWS extract for superoxide anion, singlet oxygen, hydroxy radical, hypochlorite ion and linolenic acid peroxide were 0.23 ± 0.02, 0.89 ± 0.06, 0.067 ± 0.005, 0.098 ± 0.009 and 0.020 ± 0.004 mg/ml (n=3), respectively. The quenching effects of the NWS extract on superoxide anion, singlet oxygen, hydroxy radical and hypochlorite ion were significantly higher than those of the commercially-available hexane extracts of rosemary at 1.0 mg/ml (p<0.05). The WS extract also showed higher quenching effects (except for singlet oxygen) and its EC50 values were 0.30 ± 0.02 for superoxide, 0.0048 ± 0.0005 for hydroxy radical, 0.58 ± 0.05 for hypochlorite ion and 0.13 ± 0.03 mg/ml for linolenic acid peroxide. The two extracts prepared might be available as antioxidants for foodstuffs.