Responses of Probiotic Lactic Acid Bacteria to Dietary Isoflavone

Abstract

The objective of this study was to investigate the metabolic response of probiotic lactic acid bacteria L.casei towards isoflavones consumed through traditional Indian food. The tolerance of L.casei towards principle isoflavones (Daidzein, Genistein, Biochanin A, Formononetin, Coumestrol) were examined. Daidzein and Genistein showed higher tolerance to L.casei. The survival, growth and expression of probiotic attributes of L. casei in varying concentrations of daidzein in MRS medium and soya (containing daidzein) was monitored over a period of 24 hours; the fate of daidzein in both the combinations were then analyzed by High-performance liquid chromatography; Significant ( p<0.05) quantities of Daidzein was utilized by the probiotic culture within 16 hours( 28-37 C) from MRS media wheras daidzein at concentrations of 10-15μg/mg from Soya was completely utilized by L.casei over a period of 24 hours. Furthermore, the L.casei grown in daidzein tolerated artificial gastric juice, exhibited antagonistic activity against common enteric pathogens (Salmonella typhimurum), glutamate decaboxlation activity and cell surface hydrophobicity towards xylene . The β- galatosidase and β-glucosidase enzyme activities were observed in the presence of Daidzein exposed cultures suggesting their involvement in utilization of daidzein. The results of this study imply a possibility of incorporating the probiotic L.casei with food containing daidzein as the principle isoflavone to beneficialy impact health effects.