Lactobacillus rhamnosus JCM 2771: impact on metabolism of isoflavonoids in the fecal flora from a male equol producer.
ABSTRACT Many beneficial effects of probiotics have been reported; however, few have focussed on the effects of Lactobacillus, a probiotic, on the bioconversion of isoflavonoids. We hypothesized that Lactobacillus rhamnosus will modify the metabolism of isoflavone. In an in vitro incubation, L. rhamnosus JCM 2771 produced daidzein from daidzin along with genistein. However, daidzin and genistein were not detected in the incubation solution of daidzein with L. rhamnosus. In the fecal suspension from a male equol producer with daidzein, equol was detected in the presence of a low or high concentration of L. rhamnosus. In the fecal incubation with daidzin, the equol concentration increased with an increasing concentration of L. rhamnosus JCM 2771. L. rhamnosus affected the equol production in the in vitro incubation of daidzein with fecal flora from a male equol producer. We demonstrated for the first time that L. rhamnosus JCM 2771 could produce genistein from daidzin and affect the equol production of fecal flora from a male equol producer in vitro.
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ABSTRACT: Fecal bacteria from a healthy individual were screened for the specific bacteria involved in the metabolism of dietary isoflavonoids. Two strains of bacteria capable of producing primary and secondary metabolites from the natural isoflavone glycosides daidzin and genistin were detected. The metabolites were identified by comparison of their HPLC/mass, 1H NMR and UV spectra with those of standard and synthetic compounds. Both Escherichia coli HGH21 and the gram-positive strain HGH6 converted daidzin and genistin to the their respective aglycones daidzein and genistein. Under anoxic conditions, strain HGH6 further metabolized the isoflavones daidzein and genistein to dihydrodaidzein and dihydrogenistein, respectively. The reduction of a double bond between C-2 and C-3 to a single bond was isoflavonoid-specific by strain HGH6, which did not reduce a similar bond in the flavonoids apigenin and chrysin. Strain HGH6 did not further metabolize dihydrodaidzein and dihydrogenistein. This is the first study in which specific colonic bacteria that are involved in the metabolism of daidzin and genistin have been detected.Archives of Microbiology 11/2000; 174(6):422-428. · 1.91 Impact Factor
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ABSTRACT: The objective of this study was to enhance calcium solubility and bioavailability from calcium-fortified soymilk by fermentation with 7 strains of Lactobacillus, namely, L. acidophilus ATCC 4962, ATCC33200, ATCC 4356, ATCC 4461, L. casei ASCC 290, L. plantarum ASCC 276, and L. fermentum VRI-003. The parameters that were used are viability, pH, calcium solubility, organic acid, and biologically active isoflavone aglycone content. Calcium-fortified soymilk made from soy protein isolate was inoculated with these probiotic strains, incubated for 24 h at 37 degrees C, then stored for 14 d at 4 degrees C. Soluble calcium was measured using atomic absorption spectrophotometry (AA). Organic acids and bioactive isoflavone aglycones, including diadzein, genistein, and glycetein, were measured using HPLC. Viability of the strains in the fermented calcium-fortified soymilk was > 8.5 log(10) CFU/g after 24 h fermentation and this was maintained for 14-d storage at 4 degrees C. After 24 h, there was a significant increase (P < 0.05) in soluble calcium. L. acidophilus ATCC 4962 and L. casei ASCC 290 demonstrated the highest increase with 89.3% and 87.0% soluble calcium after 24 h, respectively. The increase in calcium solubility observed was related to lowered pH associated with production of lactic and acetic acids. Fermentation significantly increased (P < 0.05) the level of conversion of isoflavones into biologically active aglycones, including diadzein, genistein, and glycetein. Our results show that fermenting calcium-fortified soymilk with the selected probiotics can potentially enhance the calcium bioavailability of calcium-fortified soymilk due to increased calcium solubility and bioactive isoflavone aglycone enrichment.Journal of Food Science 11/2007; 72(9):M431-6. · 1.78 Impact Factor
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ABSTRACT: Probiotics and prebiotics that affect gut microflora balance and its associated enzyme activity may contribute to interindividual variation in isoflavone absorption after soy intake, possibly enhancing isoflavone bioavailability. This study examined the effects of the consumption of bioactive yogurt (a probiotic) or resistant starch (a known prebiotic) in combination with high soy intake on soy isoflavone bioavailability. Using a crossover design, chronic soy consumption was compared with soy plus probiotic yogurt or resistant starch in older male and postmenopausal females (n = 31). Isoflavone bioavailability was assessed at the beginning and end of each 5-wk dietary period by sampling plasma and urine after a standardized soy meal. Chronic soy intake did not significantly affect plasma or urinary isoflavones after the soy meal and there were no significant effects of probiotic or resistant starch treatment. However, there were trends for increased circulating plasma daidzein and genistein after the probiotic treatment and for increased plasma daidzein and genistein 24 h after soy intake with resistant starch treatment. Neither treatment induced or increased equol production, although there was a trend for increased plasma equol in "equol-positive" subjects (n = 12) after probiotic treatment. The weak or absence of effects of probiotic yogurt or resistant starch supplement to a chronic soy diet suggests that gut microflora were not modified in a manner that significantly affected isoflavone bioavailability or metabolism.Nutrition 11/2007; 23(10):709-18. · 2.86 Impact Factor