Reactive oxygen species and lipid peroxidation product-scavenging ability of yogurt organisms

The antioxidative activity of the intracellular extracts of yogurt organism s was investigated. All 11 strains tested, including five strains of Strept ococcus thermophilus and six strains of Lactobacillus delbrueckii ssp. bulg aricus, demonstrated an antioxidative effect on the inhibition of linoleic acid peroxidation. The antioxidative effect of intracellular extracts of 10 (8) cells of yogurt organisms was equivalent to 25 to 96 ppm butylated hydr oxytoluene, which indicated that all strains demonstrated excellent antioxi dative activity. The scavenging of reactive oxygen species, hydroxyl radica l, and hydrogen peroxide was studied for intracellular extracts of yogurt o rganisms. All strains showed reactive oxygen species-scavenging ability. La ctobacillus delbrueckii ssp, bulgaricus Lb demonstrated the highest hydroxy l radical-scavenging ability at 234 mu M. Streptococcus thermophilus MC and 821 and L. delbrueckii ssp. bulgaricus 448 and 449 scavenged the most hydr ogen peroxide at approximately 50 mu M. The scavenging ability of lipid per oxidation products, t-butylhydroperoxide and malondialdehyde, was also eval uated. Results showed that the extracts were not able to scavenge the t-but ylhydroperoxide. Nevertheless, malondialdehyde was scavenged well by most s trains.