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Feature-Based Molecular Networking Analysis of the Metabolites Produced by in vitro Solid-State Fermentation Reveals Pathways for the Bioconversion of Epigallocatechin Gallate

preprint
revised on 12.05.2020 and posted on 13.05.2020 by Hao-Fen Xie, Ya-Shuai Kong, Ru-Ze Li, Louis-Felix Nothias, Alexey V. Melnik, Hong Zhang, Lu-Lu Liu, Ting-Ting An, Rui Liu, Zi Yang, Jia-Ping Ke, Peng Zhang, Guan-Hu Bao, Zhong-Wen Xie, Da-Xiang Li, Xiaochun Wan, Qian-Ying Dai, Liang Zhang, Ming Zhao, Mao-Qiang An, Yan-Hua Long, Tie-Jun Ling
Dark teas are prepared by a microbial fermentation process. Flavan-3-ol B-ring fission analogues (FBRFAs) are some of the key bioactive constituents that characterise dark teas. The precursors and the synthetic mechanism involved in the formation of FBRFAs are not known. Using a unique solid-state fermentation system with β-cyclodextrin inclusion complexation, as well as targeted chromatographic isolation, spectroscopic identification, and Feature-based Molecular Networking (FBMN) on the Global Natural Products Social Molecular Networking (GNPS) web-platform, we reveal that dihydromyricetin and the FBRFAs, including teadenol A and fuzhuanin A, are derived from epigallocatechin gallate (EGCG) upon exposure to fungal strains isolated from Fuzhuan brick tea. In particular the strains from subphylum Pezizomycotina were key drivers for these B-/C-ring oxidation transformations. These are the same transformations seen during the fermentation process of dark teas. These discoveries set the stage to enrich dark teas and other food products for these health promoting constituents.

Funding

National Natural Science Foundation of China (No. 31471720)

National Natural Science Foundation of China (No. 31760225)

China Scholarship Council during the visit of Tie-Jun Ling (201408775014) to University of California San Diego

the Modern Agro-Industry Technology Research System, Ministry of Agriculture & Ministry of Finance, People’s Republic of China, National Key Research & Development Plan (2017YFD0400800)

the Open Fund of the State Key Laboratory of Tea Plant Biology and Utilization (SKLTOF201801109)

Key Grant for Innovative Province from the Department of Sciences and Technology of Anhui Province to Prof. Zhong-Wen Xie (grant No. 11080001)

the U.S. National Institutes of Health (R01 GM107550)

the European Union’s Horizon 2020 program (MSCA-GF, 704786)

History

Email Address of Submitting Author

lingtj@ahau.edu.cn

Institution

Anhui Agricultural University

Country

China

ORCID For Submitting Author

0000-0001-7059-5861

Declaration of Conflict of Interest

The authors declare no competing financial interest.

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