Inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifidobacterium longum

The inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifid obacterium longum was investigated using two lipid model systems. All eight strains, including six strains oft. acidophilus and two strains of B. long um, demonstrated an inhibitory effect on linoleic acid peroxidation. The in hibitory rates on linoleic acid peroxidation ranged from 33 to 46% when 1 m L of intracellular cell-free extract was tested. In the second model system , the cell membrane of osteoblast was used as the source for biological lip id. The results indicated that all strains were able to protect biological lipids from oxidation. The inhibition rates on cell membrane lipid peroxida tion ranged from 22 to 37%. The effect of L. acidophilus and B. longum on i nhibition of fluorescent tissue pigment accumulation was also obtained for osteoblastic cells. The inhibition rates on fluorescent tissue pigment accu mulation ranged from 20 to 39%. The antioxidative effect of each milliliter df intracellular cell-free extract of L. acidophilus and B. longum was equ ivalent to 104-172 ppm of butylated hydroxytoulene (BHT). These results ind icated that all strains demonstrated high antioxidative activity. The scave nging ability of lipid peroxidation products, tert-butyl hydroperoxide and malondialdehyde, was also evaluated. The results showed that L. acidophilus and B. longum were not able to scavenge the tert-butyl hydroperoxide. Neve rtheless, malondialdehyde was scavenged well by these strains.