Antioxidant Activity of Novel Probiotics
Undergraduates: Joshua Simpson, Jason W. Arnold and M. Andrea Azcarate-Peril
Faculty Advisor: Jason Arnold
Department: Chemistry
Probiotics are live microorganisms which, when administered in adequate amounts confer a health benefit to the host. Intraspecies variability accounts for a large percentage of the diversity within microbial communities. Moreover, variability at the strain-level can result in differences in probiotic potential between isolates of the same species. Lactobacillus rhamnosus GG, a well-known probiotic, provides significant benefits, including immunomodulation and pathogen exclusion. Other strains of L. rhamnosus have also demonstrated capabilities of free radical scavenging. Accumulation of free radicals has been associated with various diseases. In this study, we investigated the antioxidant activity of our novel human isolates of L. rhamnosus, AMC010 and AMC143, compared to well characterized strains, HN001, LC705, and GG, and wild-type strains of Escherichia coli and Enterococcus faecalis. Antioxidant activity was measured using spectrophotometric analysis of 2,2-diphenyl-1-picrylhydrazyl (DPPH), a free radical compound that absorbs light at 517 nm until reduced, making it a useful compound to assess antioxidant activity. All tested strains exhibited variable antioxidant activities. LC705 exhibited greater antioxidant activity when compared to other strains, suggesting that the strain may generate more antioxidant compounds. No differences were identified between live and heat killed bacteria, suggesting that the antioxidant molecule is heat stable.