Effects of polysaccharides on colonic targeting and colonic fermentation of ovalbumin-ferulic acid based emulsion.

Rutin is a polyphenol with beneficial pharmacological properties. However, its bioavailability is often compromised due to low solubility and poor stability. Encapsulation technologies, such as emulsion systems, have been proven to be promising delivery vehicles for enhancing the bioavailability of bioactive compounds. Thus, this study was proposed and designed to investigate the colonic targeting and colonic fermentation characteristics of rutin-loaded ovalbumin-ferulic acid-polysaccharide (OVA-FA-PS) complex emulsions. The results indicate that OVA-FA-PS emulsion effectively inhibits the degradation of rutin active substances and facilitates its transport of rutin to the colon. The analysis revealed that the OVA-FA-κ-carrageenan emulsion loaded with rutin exhibited superior elasticity and colon targeting properties compared to the OVA-FA-hyaluronic acid or OVA-FA-sodium alginate emulsions loaded with rutin in the composite emulsion. Additionally, it was observed that the rutin loaded within the OVA-FA-κ-carrageenan emulsion underwent degradation and was converted to 4-hydroxybenzoic acid during colonic fermentation.

Free and bound phenolic profiles of Radix Puerariae Thomsonii from different growing regions and their bioactivities.

The free and bound phenolic profiles and their bioactivities of radix puerariae thomsonii (RPT) cultivars from 7 growing regions in China were investigated. Total phenolic and flavonoid contents were from 148.71 to 435.32 mg gallic acid equivalents /100 g dry weight and 561.93 to 826.11 mg catechin equivalents /100 g dry weight, respectively, with 20.64-38.28% and 32.77-47.29% contribution from bound fractions. Sixteen phenolic compounds were detected in RPTs. Bound fractions contributed 28.15-70.84% to the total antioxidant activities. The cultivars from Qiannan and Guangzhou showed much higher regulatory effects on carbohydrate hydrolyzing enzymes and alcohol metabolizing enzymes than the other cultivars. The bound fractions exhibited equivalent EC50 values for alcohol metabolizing enzymes and IC50 values for carbohydrate hydrolyzing enzymes to the free fractions in RPT cultivars. Therefore, bound phenolics significantly contributed to the potential health benefits of RPT. The results provided information for the utilization of RPT for health promoting purpose.

Structural elucidation, binding sites exploration and biological activities of bound phenolics from Radix Puerariae Thomsonii.

Radix puerariae thomsonii (RPT) contains many phenolics and exhibits various health benefits. Although the free phenolics in RPT have been identified, the composition and content of bound phenolics, which account for approximately 20% of the total phenolic content, remain unknown. In this study, 12 compounds were isolated and identified from RPT-bound phenolic extracts, of which 2 were novel and 6 were reported first in RPT. ORAC and PSC antioxidant activities of 12 compounds, as well as their effects on alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), α-glucosidase, and α-amylase were evaluated. Genistein exhibited the highest ORAC activity, while daidzin demonstrated superior PSC activity. Five compounds, including two new compounds, exhibited the ability to activate both ADH and ALDH. All the compounds except 4-hydroxyphenylacetic acid methyl ester and 2,4,4'-trihydroxydeoxybenzoin demonstrated inhibitory effects on α-glucosidase and α-amylase. Alkaline hydrolysis and stepwise enzymatic hydrolysis revealed that bound phenolics in RPT mainly exist within starch.

Establishment and application of quantitative detection of Bacillus velezensis HMB26553, a biocontrol agent against cotton damping-off caused by Rhizoctonia.

A highly sensitive quantitative PCR (qPCR) method was developed for detection and quantification of Bacillus velezensis HMB26553 in cotton rhizosphere. The study aimed to develop a quantitative detection method for the strain HMB26553, and explore the relationship between its colonization of the cotton rhizosphere and its control effect. The whole genome sequence of strain HMB26553 was obtained by genome sequencing and a unique specific sequence pB-gene0026 on plasmid plaBV2 was identified by using high-throughput alignment against NCBI. Plasmid plaBV2 could be stably genetically inherited. Based on this sequence, specific primers for amplifying 106 bp and a minor groove binder (MGB) TaqMan probe for enhancing sensitivity were designed. The copy number of plaBV2 in strain HMB26553, which was 2, was confirmed by internal reference primers and the MGB TaqMan probe based on housekeeping gene gyrB. The established detection technique based on these primers and probes had high specificity and sensitivity compared to traditional plate counting method, with a detection limit of 1.5 copy genome. Using this method, the study discovered a likely correlation between the quantity of colonization in cotton rhizosphere and efficacy against cotton damping-off caused by Rhizoctonia after seed soaking and irrigation with strain HMB26553. Thus, this method provides scientific support for the rational application of strain HMB26553 in the future.

In vitro human gut microbiota fermentation of litchi pulp polysaccharides as affected by Lactobacillus pre-treatment.

In this study, litchi polysaccharides were obtained from unfermented or fermented pulp by Lactobacillus fermentum (denoted as LP and LPF, respectively). The differences between LP and LPF in the colonic fermentation characteristics and modulatory of gut microbiota growth and metabolism were investigated with an in vitro fecal fermentation model. Results revealed that the strategies of gut bacteria metabolizing LP and LPF were different and LPF with lower molecular weight (Mw) was readily utilized by bacteria. The monosaccharide utilization sequence of each polysaccharide was Ara > Gla > GalA > GlcA ≈ Glu ≈ Man. Moreover, LPF promoted stronger proliferation of Bifidobacterium, Megamonas, Prevotella, and Bacteroides and higher SCFAs production (especially acetic and butyric acids) than LP. Correlation analysis further revealed that Mw could represent an essential structural feature of polysaccharides associated with its microbiota-regulating effect. Overall, Lactobacillus fermentation pre-treatment of litchi pulp promoted the fermentation characteristics and prebiotic activities of its polysaccharide.

Complete genome sequence of Bacillus velezensis B31, a potential biocontrol agent with ability of tolerance to fusaric acid and antagonism against Fusarium oxysporum.

Bacillus velezensis B31 is tolerant to fusaric acid, exhibits antagonism against Fusarium oxysporum, and has an excellent control effect on tomato fusarium wilt. Here, we present the complete genome sequence of B31, which contains 4,056,755 bp DNA with a G + C ratio of 46.39%. The genome has 3,838 protein-coding genes.

Shatianyu dietary fiber (Citrus grandis L. Osbeck) promotes the production of active metabolites from its flavonoids during in vitro colonic fermentation.

BACKGROUND: Recent studies reveal that dietary fiber (DF) might play a critical role in the metabolism and bioactivity of flavonoids by regulating gut microbiota. We previously found that Shatianyu (Citrus grandis L. Osbeck) pulp was rich in flavonoids and DF, and Shatianyu pulp flavonoid extracts (SPFEs) were dominated by melitidin, obviously different from other citrus flavonoids dominated by naringin. The effects of Shatianyu pulp DF (SPDF) on the microbial metabolism and bioactivity of SPFEs is unknown. RESULTS: An in vitro colonic fermentation model was used to explore the effects of SPDF on the microbial metabolism and antioxidant activity of SPFEs in the present study. At the beginning of fermentation, SPDF promoted the microbial degradation of SPFEs. After 24 h-fermentation, the supplemented SPFEs were almost all degraded in SPFEs group, and the main metabolites detected were the dehydrogenation, hydroxylation and acetylation products of naringenin, the aglycone of the major SPFEs components. However, when SPFEs fermented with SPDF for 24 h, 60.7% of flavonoid compounds were retained, and SPFEs were mainly transformed to the ring fission metabolites, such as 3-(4-hydroxyphenyl) propionic acid, 3-phenylpropionic acid and 3-(3-hydroxy-phenyl) propionic acid. The fermentation metabolites of SPFEs showed stronger antioxidant activity than the original ones, with a further increase in SPDF supplemented group. Furthermore, SPFEs enriched microbiota participating in the deglycosylation and dehydrogenation of flavonoids, while co-supplementation of SPDF and SPFEs witnessed the bloom of Lactobacillaceae and Lactobacillus, contributing to the deglycosylation and ring fission of flavonoids. CONCLUSION: SDPF promote SPFEs to transform to active metabolites probably by regulating gut microbiota. © 2023 Society of Chemical Industry.

Changes in retinal and choroidal thickness and vascular density in patients with systemic lupus erythematosus: Assessed by optical coherence tomography angiography.

OBJECTIVE: The aim was to investigate the changes in retinal and choroidal thickness and vascular density in patients with systemic lupus erythematosus (SLE) using optical coherence tomography angiography (OCTA). METHODS: Twenty-nine patients with SLE (29 eyes) and 25 control subjects (25 eyes) were enrolled. SLE activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Retinal thickness (RT), inner retinal thickness (IRT), outer retinal thickness (ORT), choroidal thickness (ChT), retinal superficial vascular density (SVD), retinal deep vascular density (DVD), choriocapillary vascular density (CCVD), foveal avascular zone (FAZ), superficial FAZ (sFAZ), and deep FAZ (dFAZ) were measured using OCTA. The retinal and choroidal thickness and vascular density between the control group and SLE group were compared. The relationships between SLEDAI scores and the retinal and choroidal thickness and vascular density in SLE group were analyzed. RESULTS: The SVD was significantly increased, and the DVD and CCVD were significantly decreased in the SLE group compared to the control group (p < .05). The results of receiver operating characteristic (ROC) showed that the area under the curve (AUC) values of SVD, DVD, and CCVD were 0.873, 0.729, and 0.727, indicating a high accuracy in discriminating patients with SLE from controls. Correlation analysis showed that the SLEDAI scores were positively correlated with dFAZ (r = 0.589, p = .001) and FAZ (r = 0.451, p = .018), and negatively correlated with DVD (r = -0.491, p = .009) and CCVD (r = -0.521, p = .005). CONCLUSIONS: DVD and CCVD were decreased in the SLE and might be related to the disease activity. SVD, DVD, and CCVD may hold promise in the discovery of biomarkers for diagnosing SLE.

Quantitative detection of the Ralstonia solanacearum species complex in soil by qPCR combined with a recombinant internal control strain.

IMPORTANCE: DNA-based detection and quantification of soil-borne pathogens, such as the Ralstonia solanacearum species complex (RSSC), plays a vital role in risk assessment, but meanwhile, precise quantification is difficult due to the poor purity and yield of the soil DNA retrieved. The internal sample process control (ISPC) strain RsPC we developed solved this problem and significantly improved the accuracy of quantification of RSSC in different soils. ISPC-based quantitative PCR detection is a method especially suitable for the quantitative detection of microbes in complex matrices (such as soil and sludge) containing various PCR inhibitors and for those not easy to lyse (like Gram-positive bacteria, fungi, and thick-wall cells like resting spores). In addition, the use of ISPC strains removes additional workload on the preparation of high-quality template DNA and facilitates the development of high-throughput quantitative detection techniques for soil microbes.

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.

Suppression of mir-150-5p attenuates the anti-inflammatory effect of glucocorticoids in mice with ulcerative colitis.

Glucocorticoids have been widely used in the treatment of ulcerative colitis, but not all patients benefit from this therapy due to hormone resistance. Mir-150-5p has been reported to enhance the efficacy of glucocorticoids, and low serum mir-150-5p expression has been linked to glucocorticoid resistance in ulcerative colitis patients. The aim of this study was to elucidate the mechanisms of mir-150-5p regulation on glucocorticoid resistance. An ulcerative colitis mouse model was used to evaluate changes in ulcerative colitis symptoms, inflammatory factors, and glucocorticoid resistance-related gene expression. The results showed that mir-150-5p suppression with antagomirs did not significantly interfere with or enhance the induction of ulcerative colitis symptoms by dextran sulfate sodium, but it did attenuate the inflammation inhibitory effect of dexamethasone by abnormally regulating the expression of IL-17a, IL-10, IL-2 and IL-6 levels and myeloperoxidase activity. Mir-150-5p inhibition also induced a glucocorticoid-resistant gene expression profile in colon tissues of ulcerative colitis mice, with upregulation of p-ERK, p-JNK, and HSP90 and downregulation of p-GRa, FKBP4, and HDAC2 expression. Our results indicate that mir-150-5p suppression attenuates the anti-inflammatory effect of glucocorticoids and may function as a driver element in ulcerative colitis glucocorticoid resistance. AVAILABILITY OF DATA AND MATERIALS: All data and figures analyzed in this study are available from the corresponding author by request.

Newly formed phenolics selectively bound to the graded polysaccharides of lychee pulp during heat pump drying using UPLC-ESI-QqQ-TOF-MS/MS.

Our study investigated heat pump drying (HPD) effects on phenolic-polysaccharide adducts of three lychee pulp grades, their composition and bound phenolic contents. During HPD, the hexose content in water soluble polysaccharide (WSP) increased continuously, and the pentose and glucuronic acid contents in WSP and dilute alkali soluble pectin (ASP) together with the hexose content in ASP increased initially and then decreased due to polysaccharide hydrolases pectinase, polygalacturonase and cellulase. After HPD, the bound phenolic content in WSP, ASP and water unextractable polysaccharide (WUP) significantly increased. Protocatechualdehyde and 3,4-dihydroxybenzeneacetic acid were newly generated phenolics and the former combined with all the three polysaccharide grades, while the latter selectively combined with only WSP. During HPD, WSP and ASP surface structures were gradually broken and became loose, but WUP surface structure was a complete and rough sheet structure. Alkaline hydrolysis caused sparser, more porous surfaces of the three polysaccharide grades. The polyphenol selectivity could be related to substrate selectivity of endogenous oxidases and the type of phenolic compounds.

Lychee pulp phenolics fermented by mixed lactic acid bacteria strains promote the metabolism of human gut microbiota fermentation in vitro.

Lychee pulp phenolics possess excellent biological activities, however, changes in phenolic substances after microbial treatments are unknown. Herein, lychee pulp was fermented by Lactobacillus plantarum, Lactobacillus rhamnosus, and a mixed strain of the two, followed by an investigation of the products' colonic fermentation. In comparison to single-strain fermentation, mixed-strain fermentation significantly increased catechin and quercetin. In addition, lychee phenolics fermented by mixed strains were more conducive to the growth of gut microbiota. The results of HPLC-DAD showed that colonic fermentation further promoted the release of lychee phenolics. There was a notable increase in the content of gallic acid and quercetin, while multiple phenolics were degraded. Quercetin-3-O-rutinose-7-O-α-L-rhamnoside (QRR) and rutin were catabolized into quercetin by gut microbiota, and 4-hydroxybenzoic acid was produced from the metabolism of QRR and procyanidin B2. Lychee phenolics fermented by mixed lactic acid bacteria were easily metabolized and transformed by gut microbiota. These findings indicate that lychee pulp fermented by mixed lactic acid bacteria possesses probiotic potential, which is of great significance for the development of functional probiotic products.

Modulation effect of black rice dietary fiber on the metabolism and fermentation of cyanidin-3-glucoside in an in vitro human colonic model.

Black rice (Oryza sativa L.) is a great source of anthocyanins and dietary fiber and possesses various health-promoting properties. The modulating effect of insoluble dietary fiber (IDF) from black rice on the fermentation of cyanidin-3-O-glucoside (Cy3G) in an in vitro human colonic model, together with the possible microbiota-mediated mechanisms, was investigated. The combined Cy3G and IDF fermentation can promote the biotransformation of Cy3G into phenolic compounds such as cyanidin and protocatechuic acid with stronger antioxidant activities and increase the total production of SCFAs during the fermentation of Cy3G. 16S rRNA sequencing analysis revealed that the addition of IDF modulated the microbiota structure and bloomed Bacteroidota and Prevotellaceae-related genera, which were positively correlated with metabolites of Cy3G, thus potentially regulating the microbial metabolism of Cy3G. The work is of great significance for elucidating the material basis of the health benefits of black rice.

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.

Screening Biocontrol Agents for Cash Crop Fusarium Wilt Based on Fusaric Acid Tolerance and Antagonistic Activity against Fusarium oxysporum.

Fusarium wilt, caused by Fusarium oxysporum, is one of the most notorious diseases of cash crops. The use of microbial fungicides is an effective measure for controlling Fusarium wilt, and the genus Bacillus is an important resource for the development of microbial fungicides. Fusaric acid (FA) produced by F. oxysporum can inhibit the growth of Bacillus, thus affecting the control efficacy of microbial fungicides. Therefore, screening FA-tolerant biocontrol Bacillus may help to improve the biocontrol effect on Fusarium wilt. In this study, a method for screening biocontrol agents against Fusarium wilt was established based on tolerance to FA and antagonism against F. oxysporum. Three promising biocontrol bacteria, named B31, F68, and 30833, were obtained to successfully control tomato, watermelon, and cucumber Fusarium wilt. Strains B31, F68, and 30833 were identified as B. velezensis by phylogenetic analysis of the 16S rDNA, gyrB, rpoB, and rpoC gene sequences. Coculture assays revealed that strains B31, F68, and 30833 showed increased tolerance to F. oxysporum and its metabolites compared with B. velezensis strain FZB42. Further experiments confirmed that 10 µg/mL FA completely inhibited the growth of strain FZB42, while strains B31, F68, and 30833 maintained normal growth at 20 µg/mL FA and partial growth at 40 µg/mL FA. Compared with strain FZB42, strains B31, F68, and 30833 exhibited significantly greater tolerance to FA.

Functional Analyses of the Bacillus velezensis HMB26553 Genome Provide Evidence That Its Genes Are Potentially Related to the Promotion of Plant Growth and Prevention of Cotton Rhizoctonia Damping-Off.

Bacillus spp. is one kind of the important representative biocontrol agents against plant diseases and promoting plant growth. In this study, the whole genomic sequence of bacterial strain HMB26553 was obtained. A phylogenetic tree based on the genome and ANI (average nucleotide identity), as well as dDDH (digital DNA-DNA hybridization), was constructed, and strain HMB26553 was identified as Bacillus velezensis. Fourteen biosynthetic gene clusters responsible for secondary metabolite were predicted via anti-SMASH, and six secondary metabolites were identified by UHPLC-QTOF-MS/MS (ultra-high-performance liquid chromatography coupled to quadrupole-time-of-flight tandem mass spectrometry). When the phytopathogen Rhizoctonia solani was treated with B. velezensis HMB26553, the mycelial structure changed, ROS (reactive oxygen species) accumulated, and the mitochondrial membrane potential decreased. Characteristics of strain HMB26553 were predicted and confirmed by genomic information and experiments, such as producing IAA, siderophore, extracellular enzymes and biofilm, as well as moving and promoting cotton growth. All these results suggested the mechanisms by which B. velezensis HMB26553 inhibits pathogen growth and promotes cotton growth, which likely provided the potential biocontrol agent to control cotton Rhizoctonia damping-off.

Predicting Sliding Angles on Random Pit-Distributed Textures Using Probabilistic Neural Networks.

The three-phase contact line best reflects the sliding ability of droplets on solid surfaces. Most studies on the sliding angle (SA) of superhydrophobic surfaces are limited to regularly arranged microtextured surfaces, lacking definite models and effective methods for a complex surface of a random texture. In this study, random pits with an area ratio of 19% were generated on 1 mm × 1 mm subregions, and the subregions formed arrays on a sample surface of 10 mm × 10 mm to obtain a randomly distributed microtexture surface with no pit overlaps. Although the contact angle (CA) of randomly pitted texture was the same, the SA was different. The SA of surfaces was affected by the pit location. The location of random pits increased the complexity of the three-phase contact line movement. The continuity of the three-phase contact angle (T) can reveal the rolling mechanism of the random pit texture and predict the SA, but the relationship between the T and SA is a relatively poor linear relation (R2 = 74%), and the SA of the random pit texture can only be roughly estimated. The quantized pit coordinates and SA were used as the input and output labels for the PNN model, respectively, and the accuracy of the model convergence was 90.2%.

Effect of incorporation of broccoli residues into soil on occurrence of verticillium wilt of spring-sowing-cotton and on rhizosphere microbial communities structure and function.

Cotton verticillium wilt (CVW) represented a typical plant soil-borne disease and resulted in widespread economic losses in cotton production. However, the effect of broccoli residues (BR) on verticillium wilt of spring-sowing-cotton was not clear. We investigated the effects of BR on CVW, microbial communities structure and function in rhizosphere of two cotton cultivars with different CVW resistance using amplicon sequencing methods. Results showed that control effects of BR on CVW of susceptible cultivar (cv. EJ-1) and resistant cultivar (cv. J863) were 58.49% and 85.96%, and the populations of V. dahliae decreased by 14.31% and 34.19%, respectively. The bacterial diversity indices significantly increased in BR treatment, while fungal diversity indices significantly decreased. In terms of microbial community composition, the abilities to recruit bacteria and fungi were enhanced in BR treatment, including RB41, Gemmatimonas, Pontibacter, Streptomyces, Blastococcus, Massilia, Bacillus, and Gibberella, Plectosphaerella, Neocosmospora, Aspergillus and Preussia. However, the relative abundances of Sphingomonas, Nocardioides, Haliangium, Lysobacter, Penicillium, Mortierella and Chaetomidium were opposite tendency between cultivars in BR treatment. According to PICRUSt analysis, functional profiles prediction showed that significant shifts in metabolic functions impacting KEGG pathways of BR treatment were related to metabolism and biosynthesis. FUNGuild analysis indicated that BR treatment altered the relative abundances of fungal trophic modes. The results of this study demonstrated that BR treatment decreased the populations of V. dahliae in soil, increased bacterial diversity, decreased fungal diversity, changed the microbial community structure and function, and increased the abundances of beneficial microorganisms.

Purification, Characterization and Bioactivity of Different Molecular-Weight Fractions of Polysaccharide Extracted from Litchi Pulp.

Litchi polysaccharides are a kind of macromolecular polymers with various biological activities and a wide range of molecular weights. In this study, two separate fractions, with average molecular weights of 378.67 kDa (67.33%) and 16.96 kDa (6.95%), which were referred to as LP1 and LP2, respectively, were separated using an ultrafiltration membrane. Their physicochemical properties, and immunomodulatory and prebiotic activity were compared. The results revealed that LP2 contained more neutral sugar, arabinose, galactose and rhamnose, but less uronic acid, protein, mannose and glucose than LP1. Compared with LP1, LP2 possessed higher solubility and lower apparent viscosity. LP2 exhibited stronger stimulation on macrophage secretion of NO, TNF-α and IL-6, as well as better proliferation of Lactobacillus plantarum, Leuconostoc mesenteroides, Lactobacillus casei and Bifidobacterium adolescentis. These results suggest that an ultrafiltration membrane might be used to prepare a highly-active polysaccharide fraction from litchi pulp that may be used for food or drug development.