Novel Catabolic Pathway of Quercetin-3- O-Rutinose-7- O-α-L-Rhamnoside by Lactobacillus plantarum GDMCC 1.140: The Direct Fission of C-Ring

Guitao Huang; Mingwen Lai; Canhua Xu; Shan He; Lihong Dong; Fei Huang; Ruifen Zhang; David James Young; Hesheng Liu; Dongxiao Su

doi:10.3389/fnut.2022.849439

Novel Catabolic Pathway of Quercetin-3- O-Rutinose-7- O-α-L-Rhamnoside by Lactobacillus plantarum GDMCC 1.140: The Direct Fission of C-Ring

Front Nutr. 2022 Mar 16:9:849439. doi: 10.3389/fnut.2022.849439. eCollection 2022.

Authors

Affiliations

¹ School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou, China.
² Sericultural & Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences/Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs/Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou, China.
³ College of Engineering, Information Technology & Environment, Charles Darwin University, Darwin, NT, Australia.
⁴ Zhejiang Provincial Top Discipline of Biological Engineering (Level A), Zhejiang Wanli University, Ningbo, China.

Abstract

Lychee pulp phenolics (LPP) is mainly catabolized in the host colon, increasing the abundances of Bacteroides and Lactobacillus. Herein, five selected gut microbial strains (Bacteroides uniformis, B. thetaiotaomicron, Lactobacillus rhamnosus, L. plantarum, and L. acidophilus) were separately incubated with LPP to ascertain the specific strains participating in phenolic metabolism and the corresponding metabolites. The results indicated that B. uniformis, L. rhamnosus, and L. plantarum were involved in LPP utilization, contributing to 52.37, 28.33, and 45.11% of LPP degradation after 48 h fermentation, respectively. Unprecedentedly, the metabolic pathway of the major phenolic compound quercetin-3-O-rutinose-7-O-α-L-rhamnoside by L. plantarum, appeared to be the direct fission of C-ring at C2-O1 and C3-C4 bonds, which was proved from the occurrence of two substances with the deprotonated molecule [M-H]^- ion at m/z 299 and 459, respectively. Meanwhile, it was fully confirmed that B. uniformis participated in the catabolism of isorhamnetin glycoside and procyanidin B2. In the B. uniformis culture, kaempferol was synthesized through dehydroxylation of quercetin which could be catabolized into alphitonin by L. rhamnosus. Furthermore, LPP metabolites exerted higher antioxidant activity than their precursors and gave clues to understand the interindividual differences for phenolic metabolism by gut microbiota.

Keywords: Bacteroides uniformis; C-ring fission; Lactobacillus; gut microbiota; lychee.