Comparison of different longan polysaccharides during gut Bacteroides fermentation.

The bioactivity of polysaccharide was closely related to its fermentation utilization by gut Bacteroides, and its utilization degree was determined by various gut Bacteroides species and different polysaccharides characteristics. The effects of longan polysaccharide (LP) and LP treated by ultrasonic-assisted hydrogen peroxide for 8 h (DLP-8) on gut Bacteroides growth, and their fermentation utilization were compared. The results of LP and DLP-8 on the proliferation of six Bacteroides species showed that Bacteroides uniformis had the highest proliferation index. In fermentation by B. uniformis, DLP-8 (with a lower molecular weight), the viable count of which was higher than that of LP, was degraded more and especially utilized more glucose and glucuronic acid. The microstructure of the two polysaccharides changed differently during fermentation. Moreover, DLP-8 promoted greater short-chain fatty acids production than LP. These results indicated that the fermentation properties of DLP-8 by B. uniformis were superior to those of LP.

Unveiling biotransformation of free flavonoids into phenolic acids and Chromones alongside dynamic migration of bound Phenolics in Lactobacillus-fermented lychee pulp.

Lactobacillus strains have emerged as promising probiotics for enhancing the bioactivities of plant-based foods associated with flavonoid biotransformation. Employing microbial fermentation and mass spectrometry, we explored flavonoid metabolism in lychee pulp fermented separately by Lactiplantibacillus plantarum and Limosilactobacillus fermentum. Two novel metabolites, 3,5,7-trihydroxychromone and catechol, were exclusively identified in L. plantarum-fermented pulp. Concomitant with consumption of catechin and quercetin glycosides, dihydroquercetin glycosides, 2,4-dihydroxybenzoic acid and p-hydroxyphenyllactic acid were synthesized by two strains through hydrogenation and fission of C-ring. Quantitative analysis revealed that bound phenolics were primarily located in water-insoluble polysaccharides in lychee pulp. Quercetin 3-O-rutinoside was partially liberated from water-insoluble polysaccharides and migrated to water-soluble polysaccharides during fermentation. Meanwhile, substantial accumulations in short-chain fatty acids (increased 1.45 to 3.08-fold) and viable strains (increased by 1.97 to 2.00 Log10 CFU/mL) were observed in fermentative pulp. These findings provide broader insight into microbial biotransformation of phenolics and possible guidance for personalized nutrition.

Lychee Pulp-Derived Dietary Fiber-Bound Phenolic Complex Upregulates the SCFAs-GPRs-ENS Pathway and Aquaporins in Loperamide-Induced Constipated Mice by Reshaping Gut Microbiome.

This study aimed to investigate the effects of the lychee pulp-derived dietary fiber-bound phenolic complex (DF-BPC) on a murine model of loperamide-induced constipation and its molecular mechanism associated with gut microbiota modification. DF-BPC supplementation mitigated loperamide-induced dyschezia, intestinal hypomotility, and colonic impairment, as evidenced by the increased gastro-intestinal transit rate and mucus cell counts. By comparison, short-chain fatty acids (SCFAs) contents and relative abundances of associated genera (Butyricimonas, Clostridium, and Lactobacillus) were effectively upregulated following DF-BPC supplementation. Notably, DF-BPC significantly enhanced expressions of G protein-coupled receptor (GPR) 41 and 43, reaching 1.43- and 1.62-fold increase, respectively. Neurotransmitter secretions were simultaneously altered in DF-BPC-treated mice, suggesting upregulation of the SCFAs-GPRs-enteric nervous system pathway. The overexpression of aquaporins (AQP3, 8, and 9) was stimulated partly through GPRs activation. Mild inflammation associated with constipation was inhibited by suppressing LBP-TLR4-NF-κB signaling translocation. These findings suggest that DF-BPC from lychee pulp has the potential to alleviate constipation in mice through modifying the gut microbiome.

Social Listening for Product Design Requirement Analysis and Segmentation: A Graph Analysis Approach with User Comments Mining.

This study investigates customers' product design requirements through online comments from social media, and quickly translates these needs into product design specifications. First, the exponential discriminative snowball sampling method was proposed to generate a product-related subnetwork. Second, natural language processing (NLP) was utilized to mine user-generated comments, and a Graph SAmple and aggreGatE method was employed to embed the user's node neighborhood information in the network to jointly define a user's persona. Clustering was used for market and product model segmentation. Finally, a deep learning bidirectional long short-term memory with conditional random fields framework was introduced for opinion mining. A comment frequency-invert group frequency indicator was proposed to quantify all user groups' positive and negative opinions for various specifications of different product functions. A case study of smartphone design analysis is presented with data from a large Chinese online community called Baidu Tieba. Eleven layers of social relationships were snowball sampled, with 14,018 users and 30,803 comments. The proposed method produced a more reasonable user group clustering result than the conventional method. With our approach, user groups' dominating likes and dislikes for specifications could be immediately identified, and the similar and different preferences of product features by different user groups were instantly revealed. Managerial and engineering insights were also discussed.

Divergent metabolism of two lychee (Litchi chinensis Sonn.) pulp flavonols and their modulatory effects on gut microbiota: Discovery of hydroxyethylation in vitro colonic fermentation.

Quercetin 3-O-rutinose-7-O-α-l-rhamnoside (QRR), a characteristic lychee pulp flavonoid, has been linked to diverse bioactivities involving microbial metabolism. By integrating colonic fermentation and mass spectrometry, the catabolites including 7-O-hydroxyethyl-isorhamnetin and 3'-amino-4'-O-methyl-7-O-hydroxyethyl-isorhamnetin were unprecedently identified and unique to QRR metabolism, relative to the structural analog quercetin 3-O-rutinoside (QR) metabolism. These above-described metabolites highlighted a special biotransformation hydroxyethylation in QRR catabolism. QRR was partially deglycosylated into quercetin 3-O-glucoside-7-O-α-l-rhamnoside potentially catalyzed by Bacteroides. QR was more directly degradable to aglycone during colonic fermentation than are QRR. Unlike with QR fermentation, equivalent QRR effectively upregulated concentrations of propionic and butyric acids that were highly relevant with Faecalibacterium and Coprococcus. After fermentation, the relative abundances of Bacteroides uniformis (0.03%) and Akkermansia muciniphila (0.13%) were only upregulated by QRR among all fermentation groups, leading to the enrichments of the corresponding genera. These results further reveal the relationship between flavonoid structures and metabolic characteristics.

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.

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.

Lychee (Litchi chinensis Sonn.) Pulp Phenolics Activate the Short-Chain Fatty Acid-Free Fatty Acid Receptor Anti-inflammatory Pathway by Regulating Microbiota and Mitigate Intestinal Barrier Damage in Dextran Sulfate Sodium-Induced Colitis in Mice.

The preventive effect of lychee pulp phenolics (LPP) on dextran sulfate sodium (DSS)-induced colitis of mice and its underlying mechanisms were investigated in this research. LPP supplementation mitigated DSS-induced breakage of the gut barrier as evidenced by the increased tight junction proteins and the enhanced integrity of epithelial cells. Both LPP and 5-ASA treatments could downregulate the expressions of toll-like receptor 4 (TLR-4), NOD protein-like receptor 3 (NLRP3), and proinflammatory cytokines to normal levels. Notably, treatment with LPP at a dosage of 500 mg/kg/day effectively upregulated FFAR2 and FFAR3 expression and contents of short-chain fatty acids (SCFAs), suggesting the activation of the SCFA-FFAR (free fatty acid receptor) pathway. Consistently, the abundances of probiotic taxa and microbiota (Akkermansia, Lactobacillus, Coprococcus, and Bacteroides uniformis) associated with SCFA synthesis were elevated, whereas harmful bacteria (Enterococcus and Aggregatibacter) were suppressed. These data indicate that LPP ameliorates gut barrier damage, activates the microbiota-SCFA-FFAR signaling cascade, and suppresses the TLR4/NLRP3-NF-κB pathway, and therefore, LPP supplementation could be a promising way to protect the intestinal tract.

In vitro simulated digestion and colonic fermentation of lychee pulp phenolics and their impact on metabolic pathways based on fecal metabolomics of mice.

Lychee pulp phenolics (LPP) was subjected to four simulated gastrointestinal digestions and colonic fermentation to investigate the changes in its phenolic composition and bioactivities; the fecal metabolic profiles of LPP-fed mice were also elucidated using UHPLC-ESI-QTOF-MS/MS. After simulated salivary, gastric and intestinal digestion, slight increases in phenolic acids and (+)-catechin occurred relative to undigested LPP, whereas other flavonoids showed an opposite trend. Unlike the above-described separate simulated digestions, successive gastrointestinal digestion significantly enhanced the release of phenolic compounds (p < 0.05), gallic acid (413.79%), ferulic acid (393.69%), (+)-catechin (570.27%) and rutin (247.54%). During colonic fermentation, ten detected phenolics were utilized by gut microbes, among which procyanidin B2 (22.35%) was the most degraded. LPP fermentation accelerated the production of short-chain fatty acids (122.79%). The metabolic pathways altered by LPP including unsaturated fatty acid, biotin, and nicotinamide metabolism may be the potential regulatory mechanisms and associated with the integrity of the gut barrier. These findings indicate that LPP may act as a promising candidate to protect gut health.