Isolation and identification of an isoflavone reducing bacterium from feces from a pregnant horse

Autoři: Xie Jinglong aff001;  Li Xiaobin aff001;  Zhao Fang aff001;  Wang Chenchen aff001;  Yang Kailun aff001
Působiště autorů: Xinjiang Laboratory of Meat-and Milk-Production Herbivore Nutrition, Xinjiang Agricultural University, Urumqi, Xinjiang, China aff001
Vyšlo v časopise: PLoS ONE 14(11)
Kategorie: Research Article
doi: 10.1371/journal.pone.0223503


The aim of this research was to isolate bacteria capable of biotransforming daidzein from fresh feces from pregnant horses. A Hungate anaerobic roller tube was used for anaerobic culture. Single colonies were picked at random and incubated with daidzein. High performance liquid chromatography was used to detect whether the isolated bacteria were able to biotransform the substrate. A strain capable of reducing daidzein was selected and characterized using sequence analysis of 16S rDNA, and a phylogenetic tree was constructed. The morphological physiological and biochemical characteristics of the strain were investigated. A facultative anaerobic, Gram-positive bacterium capable of converting daidzein to dihydrodaidzein was isolated and named HXBM408 (MF992210). A BLAST search of HXBM408's 16S rDNA sequence against the GenBank database suggested that the strain has 99% similarity with Pediococcus acidilactici strain DSM (NR042057). The morphological, physiological, and biochemical characteristics of HXBM408 are very similar to those of Pediococcus. Based on these characteristics, the strain was identified as Pediococcus acidilactici. The bacterial strain HXBM408 isolated from the feces of pregnant horses was able to reduce the isoflavone daidzein to dihydrodaidzein.

Klíčová slova:

Anaerobic bacteria – Bacteria – Gastrointestinal tract – High performance liquid chromatography – Horses – Metabolites – Bacterial biochemistry – Physiological properties


1. Yang D, Yang S, Zhang B, Lu Y. Certification of reference materials for analysis of isoflavones genistin and genistein in soy products[J]. Analytical Methods, 2016, 89(8): 89–96.

2. Cassidy A, Brown J E, Hawdon A, Faughnan M S, King L J, Millward J, et al. Factors affecting the bioavailability of soy isoflavones in humans after ingestion of physiologically relevant levels from different soy foods[J]. Journal of Nutrition, 2006, 136(1): 45–51. doi: 10.1093/jn/136.1.45 16365057

3. Setchell K D, Clerici C. Equol: history, chemistry, and formation[J]. Journal of Nutrition,2010, 140(7): 1355–1362.

4. Chin-Dusting J P F, Fisher L J, Lewis T V, Piekarska A, Nestel P J, Husband A. The vascular activity of some isoflavone metabolites: implications for a cardioprotective role[J].British Journal of Pharmacology, 2001, 133(4): 595–605. doi: 10.1038/sj.bjp.0704088 11399677

5. Liang X L, Wang X L, Li Z, Hao Q H, Wang S Y. Improved in vitro assays of superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity of isoflavones and isoflavone metabolites[J]. Journal of Agricultural & Food Chemistry, 2010, 58(22): 11548–11552.

6. Setchell K D, Cole SJ. Method of defining equol-producer status and its frequency among vegetarians[J]. The Journal of Nutrition, 2006, 136(8): 2188–2193. doi: 10.1093/jn/136.8.2188 16857839

7. Yu Z T, Yao W, Zhu W Y. Isolation and identification of equol-producing bacterial strains from cultures of pig faeces[J]. Fems Microbiology Letters, 2008, 282(1): 73–80. doi: 10.1111/j.1574-6968.2008.01108.x 18328079

8. Marrian G F, Haslewood G A. Equol, a new inactive phenol isolated from the ketohydroxyoestrin fraction of mares' urine.[J]. Biochemical Journal, 1932, 26(4):1227–1232. doi: 10.1042/bj0261227 16744928

9. Hungate R E, Smith W, Clarke R T J. Suitability of Butyl Rubber Stoppers for Closing Anaerobic Roll Culture Tubes[J]. Journal of Bacteriology, 1966, 91(2): 908–909. 5327378

10. Decroos K, Vanhemmens S, Cattoir S, Boon N, Verstraete W. Isolation and characterisation of an equol-producing mixed microbial culture from a human faecal sample and its activity under gastrointestinal conditions[J]. Archives of Microbiology, 2005, 183(1): 45–55. doi: 10.1007/s00203-004-0747-4 15578160

11. Magee P J. Is equol production beneficial to health?[J]. Proceedings of the Nutrition Society, 2011, 70(1):10–18. doi: 10.1017/S0029665110003940 21092366

12. Setchell K D, Brown N M, Lydekingolsen E. The clinical importance of the metabolite equol-a clue to the effectiveness of soy and its isoflavones[J]. Journal of Nutrition, 2002, 132(12): 3577–3584. doi: 10.1093/jn/132.12.3577 12468591

13. Magee P J, Rowland I R. Phyto-oestrogens, their mechanism of action: current evidence for a role in breast and prostate cancer[J]. British Journal of Nutrition, 2004, 91(4): 513–531. doi: 10.1079/BJN20031075 15035679

14. Beck V, Rohr U, Jungbauer A. Phytoestrogens derived from red clover: an alternative to estrogen replacement therapy?[J]. Journal of Steroid Biochemistry & Molecular Biology, 2005, 94(5): 499–518.

15. Atkinson C, Berman S, Humbert O, Lampe J W. In Vitro Incubation of Human Feces with Daidzein and Antibiotics Suggests Interindividual Differences in the Bacteria Responsible for Equol Production[J]. Journal of Nutrition, 2004, 134(3): 596–599. doi: 10.1093/jn/134.3.596 14988453

16. Hur H G, Jr L J, Beger R D, Freeman J P, Rafii F. Isolation of human intestinal bacteria metabolizing the natural isoflavone glycosides daidzin and genistin[J]. Archives of Microbiology, 2000, 174(6): 422–428. doi: 10.1007/s002030000222 11195098

17. Tamura M, Tsushida T, Shinohara K. Isolation of an isoflavone-metabolizing, Clostridium-like bacterium, strain TM-40, from human faeces[J]. Anaerobe, 2007, 13(1): 32–35. doi: 10.1016/j.anaerobe.2006.10.001 17113326

18. Wang X L, Shin K H, Hur H G, Kim S I. Enhanced biosynthesis of dihydrodaidzein and dihydrogenistein by a newly isolated bovine rumen anaerobic bacterium[J]. Journal of Biotechnology, 2005, 115(3): 261–269. doi: 10.1016/j.jbiotec.2004.08.014 15639088

19. Muthyala R S, Ju Y H, Sheng S, Williams L D, Doerge D R, Katzenellenbogen B S, et al. Equol, a natural estrogenic metabolite from soy isoflavones: convenient preparation and resolution of R-and S-equols and their differing binding and biological activity through estrogen receptors alpha and beta[J]. Bioorganic & Medicinal Chemistry, 2004, 12(6): 1559–1567.

20. Bowey E, Adlercreutz H, Rowland I. Metabolism of isoflavones and lignans by the gut microflora: a study in germ-free and human flora associated rats[J]. Food & Chemical Toxicology, 2003, 41(5): 631–636.

21. Maruo T, Sakamoto M, Ito C, Toda T, Benno Y. Adlercreutzia equolifaciens gen. nov. sp. nov. an equol-producing bacterium isolated from human faeces, and emended description of the genus Eggerthella.[J]. International Journal of Systematic & Evolutionary Microbiology, 2008, 58(Pt 5): 1221–1227.

22. Tsangalis D, Ashton JF, McGill A E J, Shah N P. Enzymic transformation of isoflavone phytoestrogens in soymilk by b-glucosidaseproducing Bifidobacteria[J]. Food Sci. 2002, 67: 3104–3113.

23. Ishimi Y, Oka J, Tabata I. Effects of soybean isoflavones on bone health and its safety in post-menopausal Japanese women[J]. Clin Biochem Nutr. 2008, 43(1): 48–52.

24. Ueno T, Uchiyama S. Identification of the specific intestinal bacteria capable of metabolising soy isoflavone to equol[J]. Ann Nutr Metab. 2002, 45: 114.

25. Jin J S, Kitahara M, Sakamoto M, Hattori M, Benno Y. Slackia equolifaciens sp.nov.a human intestinal bacterium capable of producing equol[J]. International Journal of Systematic and Evolutionary Microbiology, 2010, 60(8): 1721–1724.

Článek vyšel v časopise


2019 Číslo 11