title: Determinations of the antimutagenic activities of several probiotic bifidobacteria under acidic and bile conditions against benzo[a]pyrene by a modified Ames test.
abstract: Antimutagenic activities of six bifidobacteria, after acidic and bile treatment mimicking gastrointestinal conditions, against benzo[a]pyrene (B[a]P) were determined by a modified Ames test using Salmonella typhimurium TA 100. Results showed that when bifidobacteria were treated at pH 2.0 for 3 h or 1% bile for 6 h, their antimutagenic activities against B[a]P were increased as compared to controls at pH 7.0 for 0 h. After sequential acidic pH and bile treatments, Bifidobacterium lactis Bb-12 displayed the highest antimutagenic activity (71.5%), although its viable cell number was less than 2.0 log cfu/ml. The antimutagenic activity of B. lactis Bb-12 against B[a]P was increased as pH values were increased from 2.0 to 7.0, and reaction time was extended from 1 to 3 h. However, antimutagenic activity was decreased as bile salt concentration was increased from 0.5% to 2.0%. The antimutagenic activity of B. lactis Bb-12 against B[a]P was increased in the presence of whole milk (WM), semiskimmed milk (SSM) and skimmed milk (SM). When B. lactis Bb-12 was preincubated with B[a]P and milk substrates, its antimutagenic activity was increased to 99-100%.
authors.affiliation: Department of Food Science, Chungtai Institute of Health Sciences and Technology, No. 11, Pu-tzu Lane, Pei-tun District, Taichung, 406, Taiwan, ROC.
authors.forename: Pei-Ren
authors.initials: PR
authors.lastname: Lo
authors.forename: Roch-Chui
authors.initials: RC
authors.lastname: Yu
authors.forename: Cheng-Chun
authors.initials: CC
authors.lastname: Chou
authors.forename: E-Chu
authors.initials: EC
authors.lastname: Huang
mesh_terms: D000818:Animals; D016587:Antimutagenic Agents / Q000494:pharmacology*; D001564:Benzo(a)pyrene / Q000037:antagonists & inhibitors*; D001644:Bifidobacterium / Q000502:physiology*; D015169:Colony Count, Microbial; D006863:Hydrogen-Ion Concentration; D008892:Milk / Q000382:microbiology*; D019936:Probiotics; D012486:Salmonella typhimurium / Q000254:growth & development
chemical_list: D016587:Antimutagenic Agents; D001564:Benzo(a)pyrene