Sunday, July 24, 2011
Grand Ballroom, 5th fl (Sheraton New Orleans)
Oxidative stress has been linked with many diseases in humans, and currently there is considerable interest in harnessing the antioxidant properties of organisms for human health. Natural antioxidants are found in almost all plants, microorganisms, fungi and animal tissues. The objective of the present study was to investigate the antioxidant activities of three strains of Lactobacillus viz., L. casei SB11 isolated from infant feces, L. fermentum KB10 from human milk and L. buchneri AL18 from fermented food, and compare them with the activity of L. casei Shirota (from Yakult). The Lactobacillus strains were incubated in MRS broth for 24 h, after which the cells were harvested, washed with phosphate buffer saline, sonicated and the cell-free extracts assessed for their antioxidant activities. Antioxidant activity was determined using the FRAP, DPPH and ABTS methods. Different concentrations of trolox were used as standards. The antioxidant activities of L. fermentum KB10 and L. buchneri AL18, as determined by the FRAP method, were significantly (P<0.01) lower than that of L. casei Shirota. However, there was no significant difference between L. casei Shirota and L. casei SB11. Using the DPPH assay, the antioxidant activities of L. buchneri AL18 and L. casei SB11 were significantly (P<0.01) higher and L. fermentum KB10 lower than that of L. casei Shirota. Antioxidant activities of L. fermentum KB10, L. casei SB11 and L. buchneri AL 18, determined using the ABTS method, were significantly higher (P<0.01) than that of L. casei Shirota.
Keywords: Lactobacillus, Antioxidant activity