Lipopolysaccharide Production Research Articles

New 19(10 → 9)abeo-euphane-type triterpenoids from Trichilia dregeana leaves and NO production inhibitory activities

Phytochemical investigation of the EtOAc soluble fraction from leaves of Trichilia dregeana Sond. (Meliaceae) afforded naturally rare four new pentacyclic triterpenoids (1–4), together with five known pentacyclic analogs (5–8, and 11) and two steroids (9 and 10). Their structures were elucidated by extensive spectroscopic techniques such as 1D and 2D NMR and HRESIMS data analyses. The absolute configuration of 1 was determined by using the single-crystal X-ray diffraction analysis. The nitric oxide (NO) production inhibitory assay indicated that the EtOAc fraction as well as 4 and 7 inhibited the NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with the IC50 values of 83.53 μg/mL and 81.31 and 85.71 μM, respectively. Compounds 1–4 are rare 19(10 → 9)abeo-euphane-type triterpenoids bearing a 3,10-ether bridge. To the best of our knowledge, this study is the first isolation of triterpenoids with the 3,10-ether bridge in their skeleton from the genus Trichilia, providing new insights into the chemodiversity of the terpenoids in T. dregeana.

An integrated network pharmacology approach reveals that Ampelopsis grossedentata improves alcoholic liver disease via TLR4/NF-κB/MLKL pathway.

BackgroundAlcohol-related liver damage is the most prevalent chronic liver disease, which creates a heavy public health burden worldwide. The leaves of Ampelopsis grossedentata have been considered a popular tea and traditional herbal medicine in China for more than one thousand years, and possess anti-inflammatory, antioxidative, hepatoprotective, and antiviral activities. PurposeWe explored the protective effects of Ampelopsis grossedentata extract (AGE) against chronic alcohol-induced hepatic injury (alcoholic liver disease, ALD), aiming to elucidate its underlying mechanisms. MethodsFirstly, UPLC-Q/TOF-MS analysis and network pharmacology were used to identify the constituents and elucidate the potential mechanisms of AGE against ALD. Secondly, C57BL/6 mice were pair-fed the Lieber-DeCarli diet containing either isocaloric maltodextrin or ethanol, AGE (150 and 300 mg/kg/d) and silymarin (200 mg/kg) were administered to chronic ethanol-fed mice for 7 weeks to evaluate the hepatoprotective effects. Serum biochemical parameters were determined, hepatic and ileum sections were used for histologic examination, and levels of inflammatory cytokines and oxidative stress in the liver were examined. The potential molecular mechanisms of AGE in improving ALD were demonstrated by RNA-seq, Western blotting analysis, and immunofluorescence staining. ResultsTen main constituents of AGE were identified using UPLC-Q/TOF-MS and 274 potential ALD-related targets were identified. The enriched KEGG pathways included Toll-like receptor signaling pathway, NF-κB signaling pathway, and necroptosis. Moreover, in vivo experimental studies demonstrated that AGE significantly reduced serum aminotransferase levels and improved pathological abnormalities after chronic ethanol intake. Meanwhile, AGE improved ALD in mice by down-regulating oxidative stress and inflammatory cytokines. Furthermore, AGE notably repaired damaged intestinal epithelial barrier and suppressed the production of gut-derived lipopolysaccharide by elevating intestinal tight junction protein expression. Subsequent RNA-seq and experimental validation indicated that AGE inhibited NF-κB nuclear translocation, suppressed IκB-α, RIPK3 and MLKL phosphorylation and alleviated hepatic necroptosis in mice. ConclusionIn this study, we have demonstrated for the first time that AGE protects against alcoholic liver disease by regulating the gut-liver axis and inhibiting the TLR4/NF-κB/MLKL-mediated necroptosis pathway. Therefore, our present work provides important experimental evidence for AGE as a promising candidate for protection against ALD.

Controlled production of lipopolysaccharides increases immune activation in Salmonella treatments of cancer.

Immunotherapies have revolutionized cancer treatment. These treatments rely on immune cell activation in tumours, which limits the number of patients that respond. Inflammatory molecules, like lipopolysaccharides (LPS), can activate innate immune cells, which convert tumour microenvironments from cold to hot, and increase therapeutic efficacy. However, systemic delivery of lipopolysaccharides (LPS) can induce cytokine storm. In this work, we developed immune-controlling Salmonella (ICS) that only produce LPS in tumours after colonization and systemic clearance. We tuned the expression of msbB, which controls production of immunogenic LPS, by optimizing its ribosomal binding sites and protein degradation tags. This genetic system induced a controllable inflammatory response and increased dendritic cell cross-presentation invitro. The strong off state did not induce TNFα production and prevented adverse events when injected into mice. The accumulation of ICS in tumours after intravenous injection focused immune responses specifically to tumours. Tumour-specific expression of msbB increased infiltration of immune cells, activated monocytes and neutrophils, increased tumour levels of IL-6, and activated CD8 T cells in draining lymph nodes. These immune responses reduced tumour growth and increased mouse survival. By increasing the efficacy of bacterial anti-cancer therapy, localized production of LPS could provide increased options to patients with immune-resistant cancers.

Human milk oligosaccharide 2′-fucosyllactose alleviates DSS-induced ulcerative colitis via improving intestinal barrier function and regulating gut microbiota

Ulcerative colitis (UC) is an inflammatory disease with the process recurrent and chronic. Human milk oligosaccharide 2′ fucosyllactose (2′FL) possessed unique immune response and antioxidant activities, whereas its protective effect in colitis remains unexplored. Herein so as to track the beneficial effect of 2′FL in colitis, DSS-induced colitis was established and the inflammatory response, gut microbiota, intestinal tract barrier and molecular signaling pathway were measured. Results showed that 2′FL can alleviate the colitis symptoms, reduce the number of inflammatory cells, inhibit the overproduction of transforming growth factor (TGF)-β3 and tumor necrosis factor (TNF)-α, promote the production of anti-inflammatory cytokine such as interleukin-22 (IL-22) by TGF-β/SMAD2/SMAD3/SMAD4 pathways. Furthermore, 2′FL inhibited the production of lipopolysaccharide-binding protein (LBP) and lipopolysaccharide (LPS), restored intestinal barrier integrity by enhancing the levels of occluding, claudin-1, mucin mucin-2 (MUC-2), and zonulin occludin-1 (ZO-1) and further prevent harmful substance from escaping into the body, ultimately protected the liver against oxidative damage. Moreover, 16S rRNA Gene Sequencing analysis showed that 2′FL reversed the change of gut microbiota in colitis mice by reducing the abundance of the Bacteroides, Clostridium and Turicibacter, and enhancing the abundance of Coprococcus and Prevotella. In short, 2′FL supplementation could be a promising nutritional strategy for alleviating UC, and improving related diseases.

Synthesis, biofilm formation inhibitory, and inflammation inhibitory activities of new coumarin derivatives.

Coumarins are heterocycles of great interest in the development of valuable active structures in chemistry and biological domains. The ability of coumarins to inhibit biofilm formation of Gram positive bacterium (Staphylococcus aureus), Gram negative bacterium (Escherichia coli) as well as the methicillin-resistant S. aureus (MRSA) has been previously described. In the present work, new hybrid coumarin-heterocycles have been synthesized via the reaction of coumarin-6-sulfonyl chloride and 6-aminocoumarin with different small heterocycle moieties. The biological efficacy of the new compounds was evaluated towards their ability to inhibit biofilm formation and their anti-inflammatory properties. The antimicrobial activities of the newly synthesized compounds were tested against Gram positive bacterium (S. aureus ATCC 6538), Gram negative bacterium (E. coli ATCC 25922), yeast (Candida albicans ATCC 10231) and the fungus (Aspergillus niger NRRL-A326). Compounds 4d, 4e, 4f, 6a and 9 showed significant MIC and MBC values against S. aureus, E. coli, C. albicans, and methicillin-resistant S. aureus (MRSA) with especial incidence on compound 9 which surpasses all the other compounds giving MIC and MBC values of (4.88 and 9.76µg/mL for S. aureus), (78.13 and 312.5µg/mL for E. coli), (9.77 and 78.13µg/mL for C. albicans), and (39.06 and 76.7µg/mL for MRSA), respectively. With reference to the antibiofilm activity, compound 9 exhibited potent antibiofilm activity with IC50 of 60, 133.32, and 19.67µg/mL against S. aureus, E. coli, and MRSA, (respectively) considering the reference drug (neomycin). Out of all studied compounds, the anti-inflammatory results indicated that compound 4d effectively inhibited nitric oxide production in lipopolysaccharide-(LPS-) stimulated RAW264.7 macrophage cells, giving NO% inhibition of 70% compared to Sulindac (55.2%).

Anti-Inflammatory Salicin Derivatives from the Barks of Salix tetrasperma.

The genus Salix L. is traditionally used in folk medicine to alleviate pain caused by various kinds of inflammation. In the present study, 10 undescribed salicin derivatives along with 5 known congeners were isolated from the barks of Salix tetrasperma, and their structures were elucidated by spectroscopic analyses, single-crystal X-ray diffraction, electronic circular dichroism (ECD) calculations, and chemical conversions. Compounds 4-6 significantly inhibited NO production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages, and the most active 4 obviously suppressed the production of IL-1β and IL-6 and decreased iNOS and COX-2 expression in a dose-dependent manner. Further Western blotting analysis revealed that the anti-inflammatory mechanism of 4 is possibly mediated through the MAPK and NF-κB signaling pathways.

Anti-inflammatory potential via the MAPK signaling pathway of Lactobacillus spp. isolated from canine feces.

Two probiotic candidates, Lactobacillus reuteri C1 (C1) and Lactobacillus acidophilus C5 (C5), which were previously isolated from canines, were evaluated in the present study. L. reuteri and L. acidophilus have anti-oxidant, anti-inflammatory, immune-enhancing, and anti-cancer properties and exhibit various probiotic effects in humans and animals. The strains C1 and C5 demonstrated good tolerance to acid and bile salt exposure, exhibited effective adhesion to HT-29 cell monolayer, and displayed sensitivity to antibiotics, thus affirming their probiotic characteristics. Moreover, C1 and C5 exhibited the ability to downregulate the expression of inducible NO synthase (iNOS), an immunomodulatory factor, leading to a reduction in NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. These strains also demonstrated potent anti-inflammatory effects in LPS-stimulated RAW 264.7 cells, achieved through the augmentation of anti-inflammatory cytokine IL-10 expression and the inhibition of pro-inflammatory cytokine IL-1β expression. These anti-inflammatory effects of C1 and C5 were closely associated with the mitogen-activated protein kinase (MAPK) signaling pathway. The results of the present study suggest that the C1 and C5 probiotic candidates attenuate LPS-induced inflammation via the MAPK signaling pathway and the strains can be used as probiotics considering their anti-inflammatory potential.

Signaling through the Salmonella PbgA-LapB regulatory complex activates LpxC proteolysis and limits lipopolysaccharide biogenesis during stationary-phase growth.

Salmonella enterica serovar Typhimurium (S. Typhimurium) controls lipopolysaccharide (LPS) biosynthesis by regulating proteolysis of LpxC, the rate-limiting enzyme and target of preclinical antibiotics. PbgA/YejM/LapC regulates LpxC levels and controls outer membrane (OM) LPS composition at the log-to-stationary phase transition. Suppressor substitutions in LPS assembly protein B (LapB/YciM) rescue the LPS and OM integrity defects of pbgA-mutant S. Typhimurium. We hypothesized that PbgA regulates LpxC proteolysis by controlling LapB's ability to bind LpxC as a function of the growth phase. According to existing models, when nutrients are abundant, PbgA binds and restricts LapB from interacting with LpxC and FtsH, which limits LpxC proteolysis. However, when nutrients are limited, there is debate whether LapB dissociates from PbgA to bind LpxC and FtsH to enhance degradation. We sought to examine these models and investigate how the structure of LapB enables salmonellae to control LpxC proteolysis and LPS biosynthesis. Salmonellae increase LapB levels during the stationary phase to promote LpxC degradation, which limits lipid A-core production and increases their survival. The deletion of lapB, resulting in unregulated lipid A-core production and LpxC overabundance, leads to bacterial growth retardation. Tetratricopeptide repeats near the cytosol-inner membrane interface are sufficient for LapB to bind LpxC, and remarkably, LapB and PbgA interact in both growth phases, yet LpxC only associates with LapB in the stationary phase. Our findings support that PbgA-LapB exists as a constitutive complex in S. Typhimurium, which differentially binds LpxC to control LpxC proteolysis and limit lipid A-core biosynthesis in response to changes in the environment.IMPORTANCEAntimicrobial resistance has been a costly setback for human health and agriculture. Continued pursuit of new antibiotics and targets is imperative, and an improved understanding of existing ones is necessary. LpxC is an essential target of preclinical trial antibiotics that can eliminate multidrug-resistant Gram-negative bacterial infections. LapB is a natural LpxC inhibitor that targets LpxC for degradation and limits lipopolysaccharide production in Enterobacteriaceae. Contrary to some studies, findings herein support that LapB remains in complex instead of dissociating from its presumed negative regulator, PbgA/YejM/LapC, under conditions where LpxC proteolysis is enhanced. Advanced comprehension of this critical protein-lipid signaling network will lead to future development and refinement of small molecules that can specifically interfere.

Supplementing Ryegrass Ameliorates Commercial Diet-Induced Gut Microbial Dysbiosis-Associated Spleen Dysfunctions by Gut-Microbiota-Spleen Axis.

The type and composition of food strongly affect the variation and enrichment of the gut microbiota. The gut-microbiota-spleen axis has been developed, incorporating the spleen's function and maturation. However, how short-chain fatty-acid-producing gut microbiota can be considered to recover spleen function, particularly in spleens damaged by changed gut microbiota, is unknown in geese. Therefore, the gut microbial composition of the caecal chyme of geese was assessed by 16S rRNA microbial genes, and a Tax4Fun analysis identified the enrichment of KEGG orthologues involved in lipopolysaccharide production. The concentrations of LPS, reactive oxygen species, antioxidant/oxidant enzymes, and immunoglobulins were measured from serum samples and spleen tissues using ELISA kits. Quantitative reverse transcription PCR was employed to detect the Kelch-like-ECH-associated protein 1-Nuclear factor erythroid 2-related factor 2 (Keap1-Nrf2), B cell and T cell targeting markers, and anti-inflammatory/inflammatory cytokines from the spleen tissues of geese. The SCFAs were determined from the caecal chyme of geese by using gas chromatography. In this study, ryegrass-enriched gut microbiota such as Eggerthellaceae, Oscillospiraceae, Rikenellaceae, and Lachnospiraceae attenuated commercial diet-induced gut microbial alterations and spleen dysfunctions in geese. Ryegrass significantly improved the SCFAs (acetic, butyric, propionic, isovaleric, and valeric acids), AMPK pathway-activated Nrf2 redox signaling cascades, B cells (B220, CD19, and IgD), and T cells (CD3, CD4, CD8, and IL-2, with an exception of IL-17 and TGF-β) to activate anti-inflammatory cytokines (IL-4 and IL-10) and immunoglobulins (IgA, IgG, and IgM) in geese. In conclusion, ryegrass-improved reprogramming of the gut microbiota restored the spleen functions by attenuating LPS-induced oxidative stress and systemic inflammation through the gut-microbiota-spleen axis in geese.

Alleviation of allergic asthma by rosmarinic acid via gut-lung axis

BackgroundAsthma affects 3% of the global population, leading to over 0.25 million deaths. Due to its complexity, asthma is difficult to cure or prevent, and current therapies have limitations. This has led to a growing demand for alternative asthma treatments. We found rosmarinic acid (RosA) as a potential new drug candidate from natural medicine. However, RosA has poor bioavailability and remains mainly in the gastrointestinal tract after oral administration, suggesting the involvement of gut microbiota in its bioactivity. PurposeTo investigate the mechanism of RosA in alleviating allergic asthma by gut-lung axis. MethodsWe used 16S rRNA gene sequencing and metabolites analysis to investigate RosA's modulation of gut microbiota. Techniques of molecular biology and metabolomics were employed to study the pharmacological mechanism of RosA. Cohousing was used to confirm the involvement of gut microbiota in RosA-induced improvement of allergic asthma. ResultsRosA decreased cholate levels from spore-forming bacteria, leading to reduced 5-hydroxytryptamine (5-HT) synthesis, bronchoconstriction, vasodilation, and inflammatory cell infiltration. It also increased short-chain fatty acids (SCFAs) levels, facilitating the expression of intestinal tight junction proteins to promote intestinal integrity. SCFAs upregulated intestinal monocarboxylate transporters (MCTs), thereby improving their systemic delivery to reduce Th2/ILC2 mediated inflammatory response and suppress eosinophil influx and mucus production in lung. Additionally, RosA inhibited lipopolysaccharide (LPS) production and translocation, leading to reduced TLR4-NFκB mediated pulmonary inflammation and oxidative stress. ConclusionsThe anti-asthmatic mechanism of oral RosA is primarily driven by modulation of gut microbiota-derived 5-HT, SCFAs, and LPS, achieving a combined synergistic effect. RosA is a safe, effective, and reliable drug candidate that could potentially replace glucocorticoids for asthma treatment.

The basic chemical substances of total alkaloids of Uncaria rhynchophylla and their anti-neuroinflammatory activities

To clarify the chemical basis of the total alkaloids of Uncaria rhynchophylla, HPLC-VWD chromatogram of total alkaloids was established. Under its guidance, modern chromatographic and spectroscopic techniques were used to track, isolate and identify the representative principal components. As a result, one new monoterpenoid indole alkaloid, 3S,15S-N4-methoxymethyl-geissoschizine methyl ether (1), together with 20 known alkaloids (2-21), and 5 other known compounds (22-26) were obtained. Meanwhile, sixteen characteristic peaks were identified from the total alkaloids using HPLC analysis. Then, the anti-neuroinflammatory effect of compounds 1-21 was assessed through inhibiting nitric ­­­oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells. Among them, compounds 1, 3, 7, 8, 11, 12, 19 and 21 showed potent inhibitory activities with IC50 values of 5.87–76.78 μM.

Fingolimod Inhibits Exopolysaccharide Production and Regulates Relevant Genes to Eliminate the Biofilm of K. pneumoniae.

Klebsiella pneumoniae (K. pneumoniae) exhibits the ability to form biofilms as a means of adapting to its adverse surroundings. K. pneumoniae in this biofilm state demonstrates remarkable resistance, evades immune system attacks, and poses challenges for complete eradication, thereby complicating clinical anti-infection efforts. Moreover, the precise mechanisms governing biofilm formation and disruption remain elusive. Recent studies have discovered that fingolimod (FLD) exhibits biofilm properties against Gram-positive bacteria. Therefore, the antibiofilm properties of FLD were evaluated against multidrug-resistant (MDR) K. pneumoniae in this study. The antibiofilm activity of FLD against K. pneumoniae was assessed utilizing the Alamar Blue assay along with confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and crystal violet (CV) staining. The results showed that FLD effectively reduced biofilm formation, exopolysaccharide (EPS), motility, and bacterial abundance within K. pneumoniae biofilms without impeding its growth and metabolic activity. Furthermore, the inhibitory impact of FLD on the production of autoinducer-2 (AI-2) signaling molecules was identified, thereby demonstrating its notable anti-quorum sensing (QS) properties. The results of qRT-PCR analysis demonstrated that FLD significantly decreased the expression of genes associated with the efflux pump gene (AcrB, kexD, ketM, kdeA, and kpnE), outer membrane (OM) porin proteins (OmpK35, OmpK36), the quorum-sensing (QS) system (luxS), lipopolysaccharide (LPS) production (wzm), and EPS production (pgaA). Simultaneously, FLD exhibited evident antibacterial synergism, leading to an increased survival rate of G. mellonella infected with MDR K. pneumoniae. These findings suggested that FLD has substantial antibiofilm properties and synergistic antibacterial potential for colistin in treating K. pneumoniae infections.

GLUT1 regulates the release of VEGF-A in the alveolar epithelium of lipopolysaccharide-induced acute lung injury.

Acute lung injury (ALI) is a severe disease with high mortality and poor prognosis, characterized by excessive and uncontrolled inflammatory response. Vascular endothelial growth factor A (VEGF-A) contributes to the development and progression of ALI. The aim of this study was to evaluate the role of glucose transporter 1 (GLUT1) in alveolar epithelial VEGF-A production in lipopolysaccharide (LPS)-induced ALI. An ALI mouse model was induced by LPS oropharyngeal instillation. Mice were challenged with LPS and then treated with WZB117, a specific antagonist of GLUT1. For the vitro experiments, cultured A549 cells (airway epithelial cell line) were exposed to LPS, with or without the GLUT1 inhibitors WZB117 or BAY876. LPS significantly upregulated of GLUT1 and VEGF-A both in the lung from ALI mice and in cultured A549. In vivo, treatment with WZB117 not only markedly decreased LPS-induced pulmonary edema, injury, neutrophilia, as well as levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α in bronchoalveolar lavage fluid (BALF), but also reduced VEGF-A production. Yet, the maximum tolerated concentration of WZB117 failed to suppress LPS-induced VEGF-A overexpression in vitro. While administration of BAY876 inhibited gene and protein expression as well as secretion of VEGF-A in response to LPS in A549. These results illustrated that GLUT1 upregulates VEGF-A production in alveolar epithelia from LPS-induced ALI, and inhibition of GLUT1 alleviates ALI.

Dimeric diarylheptanoids with anti-inflammatory activity from Zingiber officinale

Two previously undescribed chain diarylheptanoid derivatives (2-3), five previously undescribed dimeric diarylheptanoids (4–8), together with one known cyclic diarylheptanoid (1) were isolated from Zingiber officinale. Their structures were elucidated by extensive spectroscopic analyses (HR-ESI-MS, IR, UV, 1D and 2D NMR) and ECD calculations. Biological evaluation of compounds 1–8 revealed that compounds 2, 3 and 4 could inhibit nitrite oxide and IL-6 production in lipopolysaccharide induced RAW264.7 cells in a dose-dependent manner.

Pharmacological activities of extracts from different parts of <i>Cirsium japonicum</i> var <i>spinossimum</i>

Purpose: To evaluate the antioxidant, anti-inflammatory, inhibitory and cell proliferation activities of Cirsium japonicum (C. japonicum) var. spinossimum.
 Methods: Phytochemicals (polyphenols, flavonoids, and silymarin) in leaves, roots, and seeds of C. japonicum var. spinossimum were quantified using high-performance liquid chromatography (HPLC). Antioxidant activity was investigated on 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. Anti-inflammatory activity was investigated on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 cells. Immunostimulant and hair loss prevention was confirmed through 3'-{1-((phenylamino)-carbonyl)-3, 4-tetrazolium}bis(4-methoxy-6-nitro)benzenesulfonic acid hydrate (XTT)-based cell proliferation assays using Jurkat cells and human follicle dermal papilla cells (HFDPC).
 Results: Extract from seeds exhibited the highest total polyphenol content (610.08 ± 32.40 mg GAE/g), as well as the highest total flavonoid content, while the total polyphenol content of leaves and root extracts were similar. The RC50 values for seed extract against ABTS and DPPH radicals were 8.20 ± 0.02 µg/mL and 40.13 ± 2.47 µg/mL, respectively. In particular, all six Silymarin derivatives were found to be highest in the seed extract. The C. japonicum var. spinossimum seed extract (CSE) showed significant (p < 0.05) nitric oxide (NO) inhibitory activity in RAW264.7 cells induced by LPS at all concentrations (12.5, 25, 50, 100 and 200 µg/mL) and exhibited significant (p < 0.05) cell proliferation activity in Jurkat and hair follicle dermal papilla cells (HFDPC) at 25 µg/mL.
 Conclusion: Extract of C. japonicum var. spinossimum seeds contain polyphenols and flavonoids and show significant NO inhibitory and cell proliferation activity in Jurkat and HFDPC. Therefore, Cirsium japonicum is a promising source of anti-inflammatory and anticancer agents.

Four New Steroidal Saponins from the Roots of Dracaena cambodiana with NO Production Inhibition Activity in LPS Activated RAW 264.7 Cells.

Seven steroidal saponins including three new 16,23-cyclocholestanes (1-3) and one new pregane (4) were isolated from the roots of Dracaena cambodiana Pierre ex Gagnep. Their chemical structures were elucidated to be (23R,25R)-26-O-β-D-glucopyranosyl-16,23-cyclocholesta-5,17(20)-dien-22-one-3β,16α,26-triol-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→3)]-β-D-glucopyranoside (1), (23R,25R)-26-O-β-D-glucopyranosyl-16,23-cyclocholesta-5,17,20(22)-trien-3β,22,26-triol-3-O-α-L-rhamnopyranosyl-(1→3)-β-D-glucopyranoside (2), (23R,25R)-16,23-cyclocholesta-5,16,20(22)-trien-3β,22,26-triol-3-O-α-L-rhamnopyranosyl-(1→3)-β-D-glucopyranoside (3), 3β-[(O-α-L-rhamnopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-gluco-pyranosyl)oxy]-pregna-5,17(20)-diene-16-one-20-carboxylic acid 4''''-O-β-D-glucopyranosylisopentyl ester (4), cambodianoside A (5), diosbulbiside C (6), and diosbulbiside D (7), by IR, HR-ESI-MS, 1D and 2D NMR spectra. Compounds 1 and 4-7 inhibited nitric oxide (NO) production in lipopolysaccharide activated RAW 264.7 cells with IC50 values ranging from 19.03±1.84 to 67.92±3.81 μM, whereas compounds 2 and 3 were inactive with IC50 values over 100 μM.

Galectin from Trichinella spiralis alleviates DSS-induced colitis in mice by regulating the intestinal microbiota

According to numerous reports, Trichinella spiralis (T. spiralis) and its antigens can reduce intestinal inflammation by modulating regulatory immunological responses in the host to maintain immune homeostasis. Galectin has been identified as a protein that is produced by T. spiralis, and its characterization revealed this protein has possible immune regulatory activity. However, whether recombinant T. spiralis galectin (rTs-gal) can cure dextran sulfate sodium (DSS)-induced colitis remains unknown. Here, the ability of rTs-gal to ameliorate experimental colitis in mice with inflammatory bowel disease (IBD) as well as the potential underlying mechanism were investigated. The disease activity index (DAI), colon shortening, inflammatory cell infiltration, and histological damage were used as indicators to monitor clinical symptoms of colitis. The results revealed that the administration of rTs-gal ameliorated these symptoms. According to Western blotting and ELISA results, rTs-gal may suppress the excessive inflammatory response-mediated induction of TLR4, MyD88, and NF-κB expression in the colon. Mice with colitis exhibit disruptions in the gut flora, including an increase in gram-negative bacteria, which in turn can result in increased lipopolysaccharide (LPS) production. However, injection of rTs-gal may inhibit changes in the gut microbiota, for example, by reducing the prevalence of Helicobacter and Bacteroides, which produce LPS. The findings of the present study revealed that rTs-gal may inhibit signalling pathways that involve enteric bacteria-derived LPS, TLR4, and NF-κB in mice with DSS-induced colitis and attenuate DSS-induced colitis in animals by modulating the gut microbiota. These findings shed additional light on the immunological processes underlying the beneficial effects of helminth-derived proteins in medicine.

Four Steroidal Saponins from the Trunks of Dracaena cambodiana with Inhibition of NO Production in LPS Activated RAW264.7 Cells.

Dracaena cambodiana Pierre ex Gagnep. is well known as a medicinal plant and widely distributed in Vietnam. Phytochemical investigation on the trunks of D. cambodiana lead to the isolation of four undescribed compounds (1-4) together with seven known ones (5-11). Their structures were determined to be pennogenin-24-yl-O-β-D-glucopyranoside (1), 17α-hydroxycambodianoside C (2), (25R)-27-hydroxypenogenin 3-O-α-L-rhamnopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (3), (3β,25R)-17α,22α-dihydroxy-furost-5-en-3-yl-O-α-L-rhamnopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (4), dracagenin A (5), 1-O-β-D-glucopyranosyl-2-hydroxy-4-allylbenzene (6), 1-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranosyl-2-hydroxy-allylbenzene (7), 2-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranosyl-1-hydroxy-allylbenzene (8), cinnamrutinoside A (9), icariside D1 (10), and seco-isolariciresinol 9-O-β-glucopyranoside (11) by extensive spectroscopic investigation, HR-ESI-MS, 1D and 2D NMR spectra. The anti-inflammatory activity of the isolated compounds was evaluated on macrophages. Compounds 1-6 significantly inhibited nitric oxide production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. Among them, compound 1 showed the best inhibitory activity with an IC50 value of 8.90±0.56 μM.

Remodulation of bacterial transcriptome after acquisition of foreign DNA: the case of irp-HPI high-pathogenicity island in Vibrio anguillarum.

The high-pathogenicity island irp-HPI is widespread in Vibrionaceae and encodes the siderophore piscibactin, as well as the regulator PbtA that is essential for its expression. In this work, we aim to study whether PbtA directly interacts with irp-HPI promoters. Furthermore, we hypothesize that PbtA, and thereby the acquisition of irp-HPI island, may also influence the expression of other genes elsewhere in the bacterial genome. To address this question, an RNAseq analysis was conducted to identify differentially expressed genes after pbtA deletion in Vibrio anguillarum RV22 genetic background. The results showed that PbtA not only modulates the irp-HPI genes but also modulates the expression of a plethora of V. anguillarum core genome genes, inducing nitrate, arginine, and sulfate metabolism, T6SS1, and quorum sensing, while repressing lipopolysaccharide (LPS) production, MARTX toxin, and major porins such as OmpV and ChiP. The direct binding of the C-terminal domain of PbtA to piscibactin promoters (PfrpA and PfrpC), quorum sensing (vanT), LPS transporter wza, and T6SS structure- and effector-encoding genes was demonstrated by electrophoretic mobility shift assay (EMSA). The results provide valuable insights into the regulatory mechanisms underlying the expression of irp-HPI island and its impact on Vibrios transcriptome, with implications in pathogenesis.IMPORTANCEHorizontal gene transfer enables bacteria to acquire traits, such as virulence factors, thereby increasing the risk of the emergence of new pathogens. irp-HPI genomic island has a broad dissemination in Vibrionaceae and is present in numerous potentially pathogenic marine bacteria, some of which can infect humans. Previous works showed that certain V. anguillarum strains exhibit an expanded host range plasticity and heightened virulence, a phenomenon linked to the acquisition of the irp-HPI genomic island. The present work shows that this adaptive capability is likely achieved through comprehensive changes in the transcriptome of the bacteria and that these changes are mediated by the master regulator PbtA encoded within the irp-HPI element. Our results shed light on the broad implications of horizontal gene transfer in bacterial evolution, showing that the acquired DNA can directly mediate changes in the expression of the core genome, with profounds implications in pathogenesis.

Chemical components as a potential resource for synthesis of organic compounds and anti-inflammatory activity of essential bark oil of Illicium verum

In this work, the essential bark oil (EBO) of Illicium verum cultivated at Cao Bang in Vietnam obtained by hydro-distillation was investigated for its chemical composition by gas chromatography-mass spectrometry (GC-MS). Trans-anethole (78.6%), estragole (13.7%), linalool (2.1%) and eucalyptol (2.0%) were determined to be the main components among 14 identified compounds, which accounted for 96.4% of the total EBO. Anti-inflammatory activity of EBO was evaluated by inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. EBO exhibited an interesting inhibitory effect on NO production in LPS-stimulated RAW246.7 cells with an inhibitory value at 93.87 μg/mL. From the starting material, trans-anethole isolated from EBO, there are two new amine-derivatives that were synthesized. The structure elucidation of these analogues of trans-anethole was carried out by 1D (1H NMR and 13C NMR) and IR spectral analysis.