Preparation of Dendrobium officinale Polysaccharide by Lactic Acid Bacterium Fermentation and Its Protective Mechanism against Alcoholic Liver Damage in Mice

Dendrobium officinale polysaccharide (DP) was prepared with lactic acid bacterium fermentation to overcome the large molecular weight and complex structure of traditional DP for improving its functional activity and application range in this work. The structure was analyzed, and then the functional activity was evaluated using a mouse model of alcoholic liver damage. The monosaccharide compositions were composed of four monosaccharides: arabinose (0.13%), galactose (0.50%), glucose (24.38%), and mannose (74.98%) with a molecular weight of 2.13 kDa. The connection types of glycosidic bonds in fermented D. officinale (KFDP) were →4)-β-D-Manp(1→, →4)-β-Glcp(1→, β-D-Manp(1→, and β-D-Glcp(1→. KFDP exhibited an excellent protective effect on alcoholic-induced liver damage at a dose of 80 mg/kg compared with polysaccharide separated and purified from D. officinale without fermentation (KDP), which increased the activity of GSH, GSH-Px, and GR and decreased the content of MDA, AST, T-AOC, and ALT, as well as regulated the level of IL-6, TNF-α, and IL-1β to maintain the normal functional structure of hepatocytes and retard the apoptosis rate of hepatocytes. The results proved that fermentation degradation is beneficial to improving the biological activity of polysaccharides. The potential mechanism of KFDP in protecting alcoholic liver damage was inhibiting the expression of miRNA-150-5p and targeting to promote the expression of Pik3r1. This study provides an important basis for the development of functional foods.

Isoleucine‐restricted diets improve high‐fat diet‐induced nonalcoholic fatty liver disease via regulating insulin resistance and gut microbiota

Obesity, caused by a long‐term high‐fat diet, is a risk factor for insulin resistance and nonalcoholic fatty liver disease (NAFLD). The gut microbiota plays an important role in NAFLD development by producing lipopolysaccharides (LPS). Isoleucine (ILE), as one of the branched‐chain amino acids (BCAAs), has a negative effect on glucose and lipid metabolism in obese mice. Therefore, we speculated that isoleucine‐restricted diets could prevent high‐fat diet‐induced insulin resistance and NAFLD. For this purpose, 30 C57BL/6J mice received a control check diet (CK), a high‐fat diet (HFD), and a isoleucine‐restricted diet (IR) for 12 weeks, respectively. The current study revealed that IR diets reversed HFD‐induced weight gain, increased fasting glucose levels, and lipid metabolism disorder. Furthermore, IR diets attenuated HFD‐induced hepatic inflammation by regulating the LPS/TLR4/NF‐κB signaling pathway. Moreover, hepatic insulin resistance and gluconeogenesis disorder were significantly improved by IR diets. In addition, IR diets reshaped HFD‐induced gut microbiota imbalance, reflected in decreasing the proportion of Proteobacteria phylum and LPS contents. Taken together, our studies support that restricting isoleucine in high‐fat diets was a novel means of preventing obesity‐induced NAFLD and insulin resistance.

Development of an in vitro co-culture model using Caco-2 and J774A.1 cells to mimic intestinal inflammation

In vitro models that mimic the pathophysiology in vivo are important tools to study mechanisms of disease and assess the pharmacology and toxicity of drugs. In this work, we report the development of a novel model of intestinal inflammation. This model is based on the co-culture of intestinal epithelial Caco-2 cells and murine J774A.1 macrophages. The model is shown to mimic the intestinal barrier in both healthy and inflamed state. In the healthy state, without external stimulation, Caco-2 and J774A.1 cells were co-cultured in one system without affecting the barrier integrity of intestinal epithelial cells and without inducing release of cytokines from macrophages. To mimic the inflamed intestine, Caco-2 cells were primed with an optimised cytokine cocktail (TNF-⍺, IFN-γ and IL-1β) and J774A.1 cells were pre-exposed to lipopolysaccharide (LPS) and IFN-γ for 24 h before combining the two cell lines into co-culture. In these conditions, a significant disruption of the epithelial barrier and an increase in pro-inflammatory cytokine (TNF-⍺ and IL-6) levels released from macrophages were detected. The data also show that inflammation in the co-culture model was temporary and reversible upon the removal of the inflammatory stimulus. This new in vitro model could be a valuable tool for investigating the safety and efficacy of drugs in the context of intestinal inflammation and provides advantages over other reported co-culture models of intestinal inflammation in terms of cost and simplicity.

A microfluidic chip for sustained oxygen gradient formation in the intestine ex vivo

The oxygen gradient across the intestine influences intestinal physiology and the microbial environment of the microbiome. The microbiome releases metabolites that communicate with enterochromaffin cells, neuronal cells, and resident immune cells to facilitate the bidirectional communication across the gut-brain axis. Measuring communication between various cell types within the intestine could provide essential information about key regulators of gut and brain health; however, the microbial environment of the intestine is heavily dependent on the physiological oxygen gradient that exists across the intestinal wall. Likewise, there exist a need for methods which enable real-time monitoring of intestinal signaling ex vivo yet this remains challenging due to the inability to adequately culture intestinal tissue ex vivo while also exposing the appropriate locations of the intestine for probe insertion and monitoring. Here, we designed and fabricated a 3D printed microfluidic device to maintain the oxygen gradient across precision cut murine intestinal slices with the capability to couple to external neurochemical recording techniques. The gradient is maintained from outlets below while allowing access to the slice from above for detection with fast scan cyclic voltammetry (FSCV) and carbon-fiber microelectrodes. A series of 11 outlet ports were designed to lay underneath the slice which were connected to channels to deliver oxygenated vs. deoxygenated media. Outlet ports were designed in an oval shape where deoxygenated media was delivered to the center of the slice and oxygenated media is delivered to the outer portion of the slice to mimic the location of oxygen across the intestine. An oxygen sensitive fluorescent dye, tris(2,2'-bipyridyl)dichlororuthenium(II), was used to characterize the tunability of the gradient. Viability of the tissue was confirmed by both fluorescence microscopy and FSCV. Additionally, we measured simultaneous serotonin and melatonin signaling with FSCV in the intestine for the first time. Overall, this chip provides a significant advance in our ability to culture intestinal slices ex vivo with the added benefit of direct access for measurements and imaging.

Fermentation enhances the amelioration effect of bee pollen on Caco-2 monolayer epithelial barrier dysfunction based on NF-κB-mediated MLCK-MLC signaling pathway

Intestinal barrier integrity is essential for normal nutrient digestion and absorption and disease resistance. This study aims to investigate how fermentation affects the ameliorative effect of bee pollen on the intestinal barrier dysfunction stimulated by interferon-γ and tumor necrosis factor (IFN-γ/TNF-α) cytokines. The results indicated that fermentation enhances the alleviating effect of bee pollen on intestinal barrier dysfunction (including elevated trans epithelial electrical resistance and decreased paracellular permeability). In addition, fermented bee pollen (FBP) significantly decreased (p < 0.05) the secretion levels of interleukin (IL)-6, IL-8, and IL-1β and expression of cyclooxygenase (COX)-2 protein in intestinal barrier cells. Furthermore, fermentation improved the ability of bee pollen to up-regulate the expression of tight junction proteins including zonula occludens (ZO)-1, occluding, and claudin-1. Notably, FBP showed stronger ability to inhibit the expression of nuclear factor kappa-B (NF-κB) mediated myosin light chain kinase (MLCK) and myosin light chain (MLC) signaling pathway associated with phosphorylated proteins. Overall, our results indicated that fermentation enhances the protective effect of bee pollen on the intestinal barrier, and FBP has promising potential to be used as a novel functional food to protect the intestinal barrier.

A comprehensive quality evaluation for Huangqi Guizhi Wuwu decoction by integrating UPLC-DAD/MS chemical profile and pharmacodynamics combined with chemometric analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Huangqi Guizhi Wuwu Decoction (HGWD), a classical Chinese formula originally recorded in Jin Kui Yao Lue, was used for the treatment of human "blood impediment" (a type of "Bi" syndrome). In clinical practice, HGWD has been applied to treat rheumatoid arthritis (RA).

AIM OF THE STUDY

The characterization of chemical markers reflecting both efficacy and chemical characteristics is of great significance for TCM quality control. With the anti-RA effects of HGWD as an example, the aim of this study was to develop a comprehensive strategy combining the overall chemical profile and biological activity data to identify chemical markers.

MATERIALS AND METHODS

First, an ultra-performance liquid chromatography-diode array detector (UPLC-DAD) fingerprint was established and validated to evaluate the holistic quality of HGWD of different origins. Characteristic markers associated with HGWD from different geographical origins were screened by a combination of UPLC-DAD fingerprint and chemometrics methods. Second, the chemical profiles of the 15 batches of HGWD samples were characterized by UPLC coupled tohybrid linear ion trap-Orbitrap mass spectrometry (UPLC-HRMS). The in vitro anti-RA activities of the 15 HGWD samples were then evaluated. Third, spectrum-effect relationship analysis was performed to identify bioactive compounds that could potentially be used as quality markers. Finally, a UPLC-triple quadrupole tandem mass spectrometry approach was optimized and established for quantitative analysis of the characteristic and quality markers in 15 batches of HGWD.

RESULTS

In total, 30 common peaks were assigned in the UPLC-DAD fingerprint. Nine peaks were recognized and considered characteristic markers: protocatechuic acid, coumarin, cinnamic acid, oxypaeoniflorin, paeoniflorin, calycosin, formononetin, catechin, and albiflorin. Furthermore, ninety-five common compounds were identified in the UPLC-HRMS chemical profile. The pharmacological analysis indicated that the anti-RA activities of the 15 HGWD samples were vastly different. The spectrum-effect relationship analysis revealed 30 potential bioactive constituents positively correlated with anti-RA activity. Among them, five compounds with relative amounts >1%, paeoniflorin, astragaloside IV, hexahydrocurcumin, formononetin and calycosin-7-glucoside, were selected as quality markers, and their activity was verified in LPS-induced RAW264.7 macrophages. Finally, the above 12 representative components were simultaneously quantified in the 15 batches of HGWD samples.

CONCLUSION

Combining a holistic chemical profile with representative component evaluation, this systematic strategy could be a reliable and effective method to improve quality evaluations of HGWD.

Withaferin A: A potential selective glucocorticoid receptor modulator with anti-inflammatory effect

Glucocorticoids have been widely applied to various clinical treatment, however some serious side effects may occur during the treatment. It is widely known that glucocorticoids produce a marked effect through binding to glucocorticoid receptor (GR). As withaferin A can provide multiple health benefits, this work aims to confirm withaferin A as a potential selective GR modulator with anti-inflammatory effect. Fluorescence polarization assay confirmed that withaferin A could steadily bind to GR with an IC50 value of 203.80 ± 0.36 μM. Meanwhile, glucocorticoid receptor translocation of withaferin A was measured by nuclear fractionation assay. Dual luciferase reporter assay showed that withaferin A did not activate GR transcription. Furthermore, withaferin A decreased the GR-related protein expression with less side effects. The result of molecular docking showed that hydrogen-bonding and hydrophobic interactions contributed to the binding of withaferin A with GR. In addition, the GR-withaferin A complex maintained a stable binding throughout the dynamics simulation process. Enzyme-linked immunosorbent assay showed that withaferin A inhibited the production of cytokines, confirming its anti-inflammatory effect. These findings indicate that withaferin A is a potential selective GR modulator and this work may provide a research basis for developing dietary supplements and nutraceuticals against inflammation.

Integrated Analysis of Metabolomics Combined with Network Pharmacology and Molecular Docking Reveals the Effects of Processing on Metabolites of Dendrobium officinale

Dendrobium officinale (D. officinale) is a precious medicinal species of Dendrobium Orchidaceae, and the product obtained by hot processing is called "Fengdou". At present, the research on the processing quality of D. officinale mainly focuses on the chemical composition indicators such as polysaccharides and flavonoids content. However, the changes in metabolites during D. officinale processing are still unclear. In this study, the process was divided into two stages and three important conditions including fresh stems, semiproducts and "Fengdou" products. To investigate the effect of processing on metabolites of D. officinale in different processing stages, an approach of combining metabolomics with network pharmacology and molecular docking was employed. Through UPLC-MS/MS analysis, a total of 628 metabolites were detected, and 109 of them were identified as differential metabolites (VIP ≥ 1, |log2 (FC)| ≥ 1). Next, the differential metabolites were analyzed using the network pharmacology method, resulting in the selection of 29 differential metabolites as they have a potential pharmacological activity. Combining seven diseases, 14 key metabolites and nine important targets were screened by constructing a metabolite-target-disease network. The results showed that seven metabolites with potential anticoagulant, hypoglycemic and tumor-inhibiting activities increased in relative abundance in the "Fengdou" product. Molecular docking results indicated that seven metabolites may act on five important targets. In general, processing can increase the content of some active metabolites of D. officinale and improve its medicinal quality to a certain extent.

Regulatory mechanisms of the edible alga Ulva lactuca polysaccharide via modulation of gut microbiota in diabetic mice

In this study, Ulva lactuca polysaccharide (ULP) antihyperglycemic effect was assessed by monitoring changes in the gut microbiota of aging diabetic mice. The results showed that ULP alleviated type 2 diabetes by improving insulin tolerance, increasing SOD and CAT activities, and thus lowering blood glucose level. Moreover, ULP regulated the expressions of INSR and AMPK concurrent with inhibition the expression of JNK, JAK, STAT3, p16 and p38 to improve glucose metabolism dysfunction. Interestingly, the abundance of Alloprevotella and Pediococcus change might the key factor for ULP antihyperglycemic effectiveness in aging-related diabetes. These results suggest that ULP can exert a mechanism of blood glucose regulation by improving intestinal diversity composition asides from direct insulin mimetic actions.

Total flavonoid extract from Dracocephalum moldavica L. improves pulmonary fibrosis by reducing inflammation and inhibiting the hedgehog signaling pathway

Dracocephalum Moldavica L. is a traditional herb for improving pharynx and relieving cough. However, the effect on pulmonary fibrosis is not clear. In this study, we explored the impact and molecular mechanism of total flavonoid extract from Dracocephalum moldavica L. (TFDM) on bleomycin-induced pulmonary fibrosis mouse model. Lung function testing, lung inflammation and fibrosis, and the related factors were detected by the lung function analysis system, HE and Masson staining, ELISA, respectively. The expression of proteins was studied through Western Blot, immunohistochemistry, and immunofluorescence while the expression of genes was analyzed by RT-PCR. The results showed that TFDM significantly improved lung function in mice, reduced the content of inflammatory factors, thereby reducing the inflammation. It was found that expression of collagen type I, fibronectin, and α-smooth muscle actin was significantly decreased by TFDM. The results further showed that TFDM interferes with hedgehog signaling pathway by decreasing the expression of Shh, Ptch1, and SMO proteins and thereby inhibiting the generation of downstream target gene Gli1 and thus improving pulmonary fibrosis. Conclusively, these findings suggest that TFDM improve pulmonary fibrosis by reducing inflammation and inhibition of the hedgehog signaling pathway.

Gut microbiota and transcriptome profiling revealed the protective effect of aqueous extract of Tetrastigma hemsleyanum leaves on ulcerative colitis in mice

Tetrastigma hemsleyanum, a traditional Chinese medicinal plant, possesses various biological activities, including anti-inflammatory and immunomodulatory functions. The purpose of this study was to determine the alleviating effect of the water extract of Tetrastigma hemsleyanum leaves (THLW) on ulcerative colitis (UC) and its relationship with gut microbiota. The administration of THLW significantly decreased the severity of dextran sulfate sodium (DSS)-induced intestinal damage, as demonstrated by the stabilization of body weight and colon length, and decreased disease activity index (DAI) and histological scores. THLW also decreased NF-κB protein expression in colon tissues and reduced the serum levels of IL-6, IL-1β, and TNF-α. Further co-housing experiment confirmed that the anti-UC effect of THLW was possibly by regulating the structure and composition of gut microbiota, including increasing the abundance of Oscillospiraceae, Prevotellaceae and Corynebacterium. Additionally, the expression of genes related to inflammation and immunity was also regulated by THLW treatment as evidenced by transcriptome analysis. These results suggested that the protective effect of THLW on DSS-induced colitis was mediated by alleviating inflammation and modulating the microbiota composition. This work proved the potent protective effects of THLW treatment on colitis and may have potential for UC relief.

Interaction between dietary fiber and bifidobacteria in promoting intestinal health

Bifidobacteria are considered as probiotics due to their role in promoting intestinal health, including regulating intestinal flora, controlling glycolipid metabolism, anti-colitis effects. Dietary fiber is considered as prebiotic favoring gut health. It also can be used as carbon source to support the growth and colonization of probiotics like bifidobacteria. However, because of genetic diversity, different bifidobacterial species differ in their ability to utilize dietary fiber. Meanwhile, dietary fiber with different structural properties has different effects on the bifidobacteria proliferation. The interaction between dietary fiber and bifidobacteria will consequently lead to a synergistic or antagonistic function in promoting intestinal health, therefore affecting the application of combined use of dietary fiber and bifidobacteria. In this case, we summarize the biological function of bifidobacteria, and their interaction with different dietary fiber in promoting gut health, and finally provide several strategies about their combined use.

Dendrobium officinale Xianhu 2 polysaccharide helps forming a healthy gut microbiota and improving host immune system: An in vitro and in vivo study

Dendrobium officinale is widely consumed owing to its numerous beneficial effects. We aimed to characterize polysaccharides of Dendrobium officinale (DOP) from the stems of Dendrobium officinale Xianhu 2 and clarify whether it benefit the intestinal microbiota and the immune system. The DOP weighed 291 kDa and comprised mannose, glucose, galactose, and rhamnose at 59.31:33.31:1.00:0.51 M ratio. In in vitro/vivo studies, DOP significantly increased benign intestinal microbe proportion (Lactobacillus, etc.), but reduced harmful bacteria (Escherichia_Shigella) (P < 0.05), and significantly increased butyric acid production (P < 0.05). Concentrations of 2 g/L DOP for in vitro fermentation and 100 mg/kg body weight for the mouse model were effective. In mice, DOP significantly reduced CRP, CD3, CD4, and TNF-α levels and increased C4 levels (P < 0.05). DOP might influence the immune system indirectly through regulation of the gut microbiota. Its possible regulation mechanism was that DOP reduced CD4+ Th cells proliferation so that reduced the secretion of TNF-α.

Hepatoprotective Mechanism of Ginsenoside Rg1 against Alcoholic Liver Damage Based on Gut Microbiota and Network Pharmacology

Alcoholic liver disease (ALD) is a major public health problem worldwide, which needs to be effective prevention. Ginsenoside Rg1 (GRg1), a bioactive ingredient extracted from ginseng, has benefit effects on health. In this study, 11 potential targets of GRg1 against ALD were firstly obtained by network pharmacology. KEGG pathway enrichment showed that GRg1-target-ALD was closely related to Toll-like receptor (TLR) and nuclear factor-kappa B (NF-κB) signaling pathways. In addition, GRg1 decreased antioxidant levels and increased oxidative levels in alcohol-treated mice, which alleviated oxidative stress-induced hepatic damage. GRg1 enhanced intestinal barrier function via upregulating the levels of tight junction protein and immunoglobulin A. GRg1 also reduced alcohol-induced inflammation by suppressing TLR4/NF-κB pathway, which was consistent with the prediction of network targets. Moreover, GRg1 altered GM population, and Verrucomicrobia, Bacteroidetes, Akkermansia, Bacteroides, Lachnospiraceae_NK4A136_group, and Alloprevotella played positive association with intestinal barrier indicators and negative correlation with hepatic inflammation biomarkers. The results suggest that GRg1 administration might be a promising strategy for protection of alcohol-induced liver damage.

Proanthocyanidin oligomers extract from hawthorn mediates cell cycle arrest, apoptosis, and lysosome vacuolation on HCT116 cells

In this study, Hawthorn oligomic procyanidins extracts (HPOE) were evaluated for their anticancer activity on colorectal cancer. Our results showed that HPOE arrested HCT116 cells cycle at G2/M phase through P53-Cyclin B pathway and promoted apoptosis partly via mitochondrial (Caspase 9-Caspase 3) and death receptor (Caspase 8-Caspase 3) pathways. Meanwhile, it was found that HPOE aggravated HCT116 cells death through lysosomal vacuolation, which was verified by inhibitor/activator of P53-ILC3 signaling pathway. Taken together, HPOE exerted anticancer effects which lays the foundation for the development of functional foods for clinical colon cancer patients.

Ferroptosis Related Immunomodulatory Effect of a Novel Extracellular Polysaccharides from Marine Fungus Aureobasidium melanogenum

Marine fungi represent an important and sustainable resource, from which the search for novel biological substances for application in the pharmacy or food industry offers great potential. In our research, novel polysaccharide (AUM-1) was obtained from marine Aureobasidium melanogenum SCAU-266 were obtained and the molecular weight of AUM-1 was determined to be 8000 Da with 97.30% of glucose, 1.9% of mannose, and 0.08% galactose, owing to a potential backbone of α-D-Glcp-(1→2)-α-D-Manp-(1→4)-α-D-Glcp-(1→6)-(SO3-)-4-α-D-Glcp-(1→6)-1-β-D-Glcp-1→2)-α-D-Glcp-(1→6)-β-D-Glcp-1→6)-α-D-Glcp-1→4)-α-D-Glcp-6→1)-[α-D-Glcp-4]26→1)-α-D-Glcp and two side chains that consisted of α-D-Glcp-1 and α-D-Glcp-(1→6)-α-D-Glcp residues. The immunomodulatory effect of AUM-1 was identified. Then, the potential molecular mechanism by which AUM-1 may be connected to ferroptosis was indicated by metabonomics, and the expression of COX2, SLC7A11, GPX4, ACSL4, FTH1, and ROS were further verified. Thus, we first speculated that AUM-1 has a potential effect on the ferroptosis-related immunomodulatory property in RAW 264.7 cells by adjusting the expression of GPX4, regulated glutathione (oxidative), directly causing lipid peroxidation owing to the higher ROS level through the glutamate metabolism and TCA cycle. Thus, the ferroptosis related immunomodulatory effect of AUM-1 was obtained.

Dendrobium nobile Lindley Administration Attenuates Atopic Dermatitis-like Lesions by Modulating Immune Cells

Atopic dermatitis (AD) is a chronic inflammatory skin disease that can significantly affect daily life by causing sleep disturbance due to extreme itching. In addition, if the symptoms of AD are severe, it can cause mental disorders such as ADHD and suicidal ideation. Corticosteroid preparations used for general treatment have good effects, but their use is limited due to side effects. Therefore, it is essential to minimize the side effects and study effective treatment methods. Dendrobium nobile Lindley (DNL) has been widely used for various diseases, but to the best of our knowledge, its effect on AD has not yet been proven. In this study, the inhibitory effect of DNL on AD was confirmed in a DNCB-induced Balb/c mouse. In addition, the inhibitory efficacy of inflammatory cytokines in TNF-α/IFN-γ-induced HaCaT cells and PMACI-induced HMC-1 cells was confirmed. The results demonstrated that DNL decreased IgE, IL-6, IL-4, scratching behavior, SCORAD index, infiltration of mast cells and eosinophils and decreased the thickness of the skin. Additionally, DNL inhibited the expression of cytokines and inhibited the MAPK and NF-κB signaling pathways. This suggests that DNL inhibits cytokine expression, protein signaling pathway, and immune cells, thereby improving AD symptoms in mice.

Dietary proanthocyanidins on gastrointestinal health and the interactions with gut microbiota

Many epidemiological and experimental studies have consistently reported the beneficial effects of dietary proanthocyanidins (PAC) on improving gastrointestinal physiological functions. This review aims to present a comprehensive perspective by focusing on structural properties, interactions and gastrointestinal protection of PAC. In brief, the main findings of this review are summarized as follows: (1) Structural features are critical factors in determining the bioavailability and subsequent pharmacology of PAC; (2) PAC and/or their bacterial metabolites can play a direct role in the gastrointestinal tract through their antioxidant, antibacterial, anti-inflammatory, and anti-proliferative properties; (3) PAC can reduce the digestion, absorption, and bioavailability of carbohydrates, proteins, and lipids by interacting with them or their according enzymes and transporters in the gastrointestinal tract; (4). PAC showed a prebiotic-like effect by interacting with the microflora in the intestinal tract, and the enhancement of PAC on a variety of probiotics, such as Bifidobacterium spp. and Lactobacillus spp. could be associated with potential benefits to human health. In conclusion, the potential effects of PAC in prevention and alleviation of gastrointestinal diseases are remarkable but clinical evidence is urgently needed.

Senegalia macrostachya seed polysaccharides attenuate inflammation-induced intestinal epithelial barrier dysfunction in a Caco-2 and RAW264.7 macrophage co-culture model by inhibiting the NF-κB/MLCK pathway

Senegalia macrostachya seed polysaccharides improved the Caco-2 cell monolayer integrity from the inflammatory insult. SMSP2 treatment lowered the inflammatory cytokine release, increased TJ proteins, and downregulated the NF-κB/MLCK pathway.

Anti-inflammatory activity of flavonols via inhibiting MAPK and NF-κB signaling pathways in RAW264.7 macrophages

Fisetin (Fis), quercetin (Que), and myricetin (Myr) are flavonols with similar structure but different number of hydroxyl groups. The present research focused on the anti-inflammatory effect of these three flavonols in lipopolysaccharide-stimulated RAW264.7 cells. The number and site of hydroxyl group in flavonols obviously affected their anti-inflammation activity. These flavonols suppressed the overproduction of nitric oxide. Fis showed the best activity with an inhibition rate of 52% at 20 μM. Moreover, the flavonols reduced the levels of ROS, TNF-α, and IL-6. The mechanistic study showed that they inhibited the activation of NF-κB and MAPK pathways by suppressing the phosphorylation of IκBα, p65, JNK, ERK, p38, MEK, and reducing the nuclear translocation of NF-κB p65. In addition, the metabolism of the flavonols was examined. The results indicated that Fis was both methylated and glucuronidated. Que and Myr were mainly transformed into methylated products. This study highlights the anti-inflammatory activity of flavonols, particularly Fis, which has the potential for the prevention or treatment of inflammation as an adjuvant medicine or food additive.

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Flavonols suppressed the production of NO and ROS.

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Flavonols partially blocked the activation of NF-κB and MAPK pathways.

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Fisetin is an excellent anti-inflammatory reagent.

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The number of hydroxyl group in flavonols obviously affects their anti-inflammation activity.

GR-mediated anti-inflammation of α-boswellic acid: Insights from in vitro and in silico studies

Although multiple bioactivities of α-boswellic acid have been reported, the molecular mechanism of its anti-inflammatory action is not yet clear. Hence, glucocorticoid receptor (GR)-mediated anti-inflammation of α-boswellic acid was investigated in this work. Fluorescence polarization assay suggested that α-boswellic acid bound to GR with IC₅₀ value of 658.00 ± 0.21 μM. Upon binding to α-boswellic acid, GR translocated from cytoplasm into nucleus of HeLa cells, facilitating sequential transcriptional regulation of GR-related genes. Luciferase reporter assay suggested that α-boswellic acid lacked GR transcriptional activity, indicating its potential as a dissociative GR ligand. Interestingly, α-boswellic acid selectively modulated the anti-inflammatory gene CBG (marker for GR transrepression), while leaving the "side-effect" gene TAT (marker for GR transactivation) unaffected in HepG2 cells. Furthermore, α-boswellic acid inhibited lipopolysaccharide-stimulated cytokines production in U937 macrophages, confirming its anti-inflammation property in vitro. Molecular docking showed that both hydrogen-bonding and hydrophobic interactions helped to stabilize α-boswellic acid-GR binding. Their binding stability was further confirmed in a 70-ns dynamics simulation. In summary, α-boswellic acid could bind to and translocate GR but did not induce glucocorticoid response element-mediated transcription. Since α-boswellic acid showed the dissociated characteristic that separated transrepression from transactivation, it might be a selective GR modulator against inflammatory disorders.