Table 2.
Enzymes and microorganisms involved in the transformation of flavonoids by human gut bacteria.
| Reaction | Enzymes | Species/Strain | Major findings | References |
|---|---|---|---|---|
| Deglycosylation | β-Glucosidase |
Bifidobacterium Adolescentis Bifidobacterium animalis subsp lactis Bifidobacterium bifidum Bifidobacterium breve Bifidobacterium catenulatum Bifidobacterium longum Bifidobacterium infantis Bifidobacterium Pseudocatenulatum |
Screened 22 strains of Bifidobacterium representative among eight major species from the human origin for their ability to bioconversion of soy isoflavones | (120) |
| Screened five Bifidobacteria strains from the human origin for their specific beta-glucosidase activity and their metabolic competence in dietary flavonoids analyzed by high-performance liquid chromatography separations | (118) | |||
| Selected two Bifidobacterium strains among 46 lactic acid bacteria for their relatively high beta-glucosidase activities with finding coding genes and successfully constructed several bifidobacteria expression vectors | (121) | |||
|
Bifidobacterium lactis Lactobacillus plantarum Lactobacillus casei Lactobacillus acidophilus |
Investigated enzymatic potential of Bifidobacteria and Lactobacillus for converting delphinidin and malvidin glycosides and screened their β-glucosidase activity | (119) | ||
|
Lactobacillus mucosae INIA P50 Lactococcus lactis MG1363 |
The genes from Lactobacillus mucosae were cloned in Lactococcus lactis with special vectors, and their high beta-glucosidase activities and abilities to efficiently catalyze were shown | (124) | ||
|
Lactobacillus casei LP71 Lactobacillus plantarum E112 Lactobacillus rhamnosus E41 Bifidobacterium pseudocatenulatum C35 |
Fermented eight lactobacilli and two bifidobacteria strains and monitored their beta-glucosidase activities | (123) | ||
| Lactic acid bacteria | Based on biochemical and genomic information, systematically summarized lactic acid bacteria having the glucosidase activities and the function of hydrolyzing plant metabolite glycoconjugates | (122) | ||
| Rhamnosidase |
Escherichia sp. 4 Escherichia sp. 34 Enterococcus sp. 45 Bacillus sp. 46 |
Characterized and isolated the intestinal bacteria from the fecal sample and investigated their conversion of bundle side using UPLC-LTQ/Orbitrap/MS/MS; as a result, four strains showed enzyme activities | (128) | |
|
Bifidobacterium longum R0175 Lactobacillus rhamnosus subsp. Rhamnosus NCTC 10302 |
Investigated the ability of two probiotic bacteria to catabolise flavanones by HPLC-HR-MS | (129) | ||
| Bifidobacterium pseudocatenultum | Investigated that bifidobacteria if could hydrolyze rutinosides by screening 33 strains and Bifidobacterium pseudocatenulatum showed the possibility in agreement with a putative alpha-l-rhamnosidase | (126) | ||
| Enterococcus avium EFEL009 | The strain was isolated and identified from the human fecal samples, and it showed enzymatic activities under anaerobic conditions | (127) | ||
|
Bacillus sp. 52 Bacteroides sp. 45, 42, 22 Veillonella sp. 32 |
Five human intestinal bacteria strains were found related to the deglycosylated route of rutin and showed α-l-rhamnosidase and β-d-glucosidase activities with using UPLC–Q-TOF/MS | (125) | ||
| Demethylation | — | Bacterium Bautia sp MRG-PMF1 | Studied the capability of the human intestinal bacterium MRG-PMF1 to the biotransformation and metabolizing of poylmethoxyflavones | (133) |
| MRG-PMF1 had the metabolic function to curcumin and other curcuminoids | (134) | |||
| MRG-PMF1 could biotransform poylmethoxyflavones to various demethylated metabolites | (135) | |||
| Eubacterium limosum | The intestinal bacterium was used to test the capacity of O-demethylation and degradation of flavonoids | (132) | ||
| Ring cleavage | — |
Enterococcus casseliflavus Eubacterium ramulus Clostridium orbiscindens sp. nov. |
The review summarized the metabolism capabilities of different flavonoids to be the ring cleavage metabolites by the intestinal bacterial and their metabolic pathways | (136) |
| Bacterium CG19-1 | Newly isolated human intestinal bacterium CG19-1 from fecal suspensions was identified to convert puerarin | (137) | ||
| — |
Eggerthella lenta rK3 Flavonifractor plautii aK2 |
Isolated two bacterial strains from the human fecal suspension that were characterized to associate with the conversion of catechins | (138) | |
| Double bond reduction | — | Clostridium orbiscindens | An anaerobic bacteria degrading quercetin isolated from human feces were identified by 16S rRNA gene sequence analysis and could transform several flavonoids under strictly anoxic conditions | (139) |