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Open Access Research article

Production of enterodiol from defatted flaxseeds through biotransformation by human intestinal bacteria

Cheng-Zhi Wang1, Xiao-Qing Ma2, Dong-Hui Yang2*, Zhi-Rong Guo1, Gui-Rong Liu35, Ge-Xin Zhao1, Jie Tang1, Ya-Nan Zhang1, Miao Ma2, Shao-Qing Cai2, Bao-Shan Ku4 and Shu-Lin Liu135*

Author Affiliations

1 Department of Microbiology, Peking University Health Science Center, Beijing 100191, China

2 Department of Natural Medicines, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China

3 Genomics Research Center (one of The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), Harbin Medical University, Harbin 150081, China

4 Department of Pharmacology, Peking University Health Science Center, Beijing, 100191, China

5 Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, AB, T2N 4N1, Canada

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BMC Microbiology 2010, 10:115  doi:10.1186/1471-2180-10-115

Published: 16 April 2010

Abstract

Background

The effects of enterolignans, e.g., enterodiol (END) and particularly its oxidation product, enterolactone (ENL), on prevention of hormone-dependent diseases, such as osteoporosis, cardiovascular diseases, hyperlipemia, breast cancer, colon cancer, prostate cancer and menopausal syndrome, have attracted much attention. To date, the main way to obtain END and ENL is chemical synthesis, which is expensive and inevitably leads to environmental pollution. To explore a more economic and eco-friendly production method, we explored biotransformation of enterolignans from precursors contained in defatted flaxseeds by human intestinal bacteria.

Results

We cultured fecal specimens from healthy young adults in media containing defatted flaxseeds and detected END from the culture supernatant. Following selection through successive subcultures of the fecal microbiota with defatted flaxseeds as the only carbon source, we obtained a bacterial consortium, designated as END-49, which contained the smallest number of bacterial types still capable of metabolizing defatted flaxseeds to produce END. Based on analysis with pulsed field gel electrophoresis, END-49 was found to consist of five genomically distinct bacterial lineages, designated Group I-V, with Group I strains dominating the culture. None of the individual Group I-V strains produced END, demonstrating that the biotransformation of substrates in defatted flaxseeds into END is a joint work by different members of the END-49 bacterial consortium. Interestingly, Group I strains produced secoisolariciresinol, an important intermediate of END production; 16S rRNA analysis of one Group I strain established its close relatedness with Klebsiella. Genomic analysis is under way to identify all members in END-49 involved in the biotransformation and the actual pathway leading to END-production.

Conclusion

Biotransformation is a very economic, efficient and environmentally friendly way of mass-producing enterodiol from defatted flaxseeds.