Bioconversion of soy isoflavones daidzin and daidzein by Bifidobacterium strains

Abstract

Twenty-two strains of Bifidobacterium, representative of eight major species of human origin, were screened for their ability to transform the isoflavones daidzin and daidzein. Most of the strains released the aglycone from daidzin and 12 gave yields higher than 90%. The kinetics of growth, daidzin consumption, and daidzein production indicated that the hydrolytic activity occurred during the growth. The supernatant of the majority of the strains did not release the aglycone from daidzin, suggesting that cell-associated beta-glucosidases (beta-Glu) are mainly responsible for the metabolism of soybean glyco-conjugates. Cell-associated beta-Glu was mainly intracellular and significantly varied among the species and the strains. The lack of beta-Glu was correlated with the inability to hydrolyze daidzin. Although S-equol production by anaerobic intestinal bacteria has been established, information on S-equol-producing bifidobacteria is contradictory. In this study, 22 bifidobacteria failed to transform daidzein into reduced metabolites under all the experimental conditions, excluding any role in the reductive pathway of daidzein toward the production of S-equol. These results suggest that selected probiotic strains of Bifidobacterium can be used to speed up the release of daidzein, improving its bioavailability for absorption by colonic mucosa and/or biotransformation to S-equol by other intestinal microorganisms.

Identification of a Saccharomyces cerevisiae Glucosidase That Hydrolyzes Flavonoid Glucosides

“…Even the endophytic bacterium Pseudomonas strain ZD-8 (61), as well as cell-associated ␤-GHs (bglH and yckE) from Bacillus subtilis natto, used for fermentation of soy products (28), were shown to metabolize apigenin 7-O-␤-glucoside or glucosides and malonylglucosides of genistein and daidzein. The capacity of multiple Bifidobacterium strains of human origin to digest isoflavonoid glucosides (32,41) is particularly noteworthy because of their relevance for the uptake of dietary isoflavones.…”

Effects of phytochemicals on in vitro anti-inflammatory activity of Bifidobacterium adolescentis

“…adolescentis possesses the genes that encode β-galactosidase 35) and β-glucosidase, 14) but not those that encode β-glucuronidase and α-L-rhamnosidase. B. adolescentis JCM1275 T converted quercetin glucosides to the aglycone forms in a time-dependent manner, but did not convert Q3GA into its aglycone.…”

“…40−42) Daidzein (log p = 2.51) 42) may be degraded but not converted into S-equol. 14) In contrast, diosmetin, hesperetin, and isorhamnetin, each of which contains a methoxy group, seem to be more sensitive to bacteria than the polymethoxyflavonoids nobiletin and tangeretin. In addition, flavones, flavonols, and flavanones may have comparatively low sensitivity to B. adolescentis JCM1275 T .…”

“…Daidzein is transformed to the more active compound S-equol by bacteria in the genera Lactobacillus, Eggerthella, and Slackia, but not by Bifidobacterium. 13,14) In contrast, the mechanism of bioconversion of flavonoids to more active compounds, while maintaining the flavonoid structure (C6-C3-C6),…”

Biotransformações dos terpenos ?-cariofileno e ácido 3?-acetoxi-copálico presentes em oleorresinas de Copaifera sp utilizando fungos filamentosos e bactérias do trato gastrointestinal e avaliação da atividade citotóxica dos derivados obtidos

“…Os modelos microbianos do metabolismo animal, baseados na similaridade do metabolismo hepático e enzimático microbiano, tornaram-se uma alternativa promissora para elucidação da rota metabólica de compostos exógenos que podem ser transformados em substâncias benéficas como no caso dos fitoestrógenos (Raimondi et al, 2009) ou prejudiciais (derivados tóxicos, mutagênicos ou carcinogênicos) como no caso do metronidazol (Faigle et al, 1993;Abourashed et al, 1999;Raimondi et al, 2009). …”