Antioxidative effect of intestinal bacteria Bifidobacterium longum ATCC 15708 and Lactobacillus acidophilus ATCC 4356

The antioxidative effect of intact cells and intracellular cell-free extrac ts of intestinal lactic acid bacteria B. longum (ATCC 15708) and L. acidoph ilus (ATCC 4356) was investigated. Both intact cells and intracellular cell -free extracts of 10(9) cells of B. longum and L. acidophilus demonstrated antioxidative activity, inhibiting linoleic acid peroxidation by 28-48%. Th is indicated that these two strains demonstrated excellent antioxidative ac tivity. B. longum and L. acidophilus also showed the ability to scavenge al pha,alpha,-diphenyl-beta-picrylhydrazyl (DPPH) free radical, scavenging 21- 52%, The intact cells of these two intestinal bacteria demonstrated a high inhibitory effect on the cytotoxicity of 4-nitroquinoline-N-oxide (4NQO), C ytotoxicity of 4NQO was reduced by L. acidophilus by approximately half and by almost 90% by B. longum. Nevertheless, no inhibition of cytoxicity obse rved for intracellular cell-free extracts of 10(9) cells of B. longum and L . acidophilus. The effect of B. longum and L. acidophilus on inhibiting pla sma lipid peroxidation was also evaluated. The results showed that both int estinal strains were able to protect plasma lipid from oxidation at differe nt degrees. The inhibition rates on plasma lipid peroxidation ranged from 1 1 to 29% for 10(9) cells of B. longum and L. acidophilus. Generally speakin g, B. longum demonstrated better antioxidative ability than L. acidophilus in this study.