Myricetin exerts anti-biofilm activity and attenuates osteomyelitis by inhibiting the TLR2/MAPK pathway in experimental mice

Gusongan capsule enhances osteogenic differentiation to mitigate bone loss in ovariectomized rats via the TLR2/NF-κB pathway

BACKGROUND

Osteoporosis (OP) is a metabolic bone disease characterized by reduced bone mass and impaired bone microstructure, leading to an increased risk of fractures. In this context, the Gusongan (GSA) capsule has gained recognition for its osteogenic potential.

PURPOSE

This study sought to examine the therapeutic effects of GSA capsule on OP and to elucidate the molecular mechanisms underpinning its osteoprotective properties.

METHODS

An OP model was established in female Sprague-Dawley rats through bilateral ovariectomy (OVX), followed by gavage administration of varying doses of GSA capsule. The study included the control, OVX model, and positive control (alendronate) groups. Bone mineral density (BMD) and serum biomarkers of rats were analyzed using micro-computed tomography (micro-CT) and enzyme-linked immunosorbent assay (ELISA). RNA sequencing (RNA-seq)- and network pharmacology-based analyses were conducted to identify potential molecular targets. Additionally, in vitro experiments were performed to evaluate the impacts of GSA capsule on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and the TLR2/NF-κB pathway.

RESULTS

Micro-CT analysis demonstrated that GSA capsule treatment markedly improved BMD, trabecular number (Tb.N), and bone volume/total volume (BV/TV), while reducing trabecular separation (Tb.Sp) (p< 0.05). ELISA results further revealed that GSA capsule diminished serum levels of bone Gla protein (BGP), bone alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase (TRACP) in OVX rats (p< 0.05), suggesting an inhibitory effect on bone resorption and turnover. RNA-seq- and network pharmacology-based analyses highlighted the downregulation of key factors in the TLR2/NF-κB pathway in BMSCs following GSA capsule treatment. Furthermore, GSA capsule enhanced BALP activity and mineralized nodule formation in BMSCs (p< 0.05). In vitro investigations corroborated that GSA capsule downregulated TLR2 and NF-κB p65 levels and fostered the expression of osteogenic genes, including COL1A1, RUNX2, and OPN (p< 0.05).

CONCLUSION

This study highlighted that GSA capsule attenuated inflammation and augmented osteogenic differentiation of BMSCs by targeting the TLR2/NF-κB pathway. These molecular mechanisms contributed to enhanced BMD and bone microarchitecture in OVX rats, suggesting the therapeutic potential of GSA capsule in OP management.

Myricetin prevents roast chicken breast-induced liver damage by regulating NF-κB/MAPK signaling pathway-mediated liver inflammation and intestine barrier damage in mice

BACKGROUND

Roast chicken breast contains a certain number of heterocyclic amines (HCAs), which induces damage of liver, colon, and other organs. Myricetin (MY) is a polyhydroxyl flavonol compound known for its anti-inflammatory and various other pharmacological activities, but its mechanisms related to alleviating HCAS-induced liver inflammation are unclear.

PURPOSE

To explore the molecular mechanism of MY alleviating RC-induced liver inflammation in mice.

STUDY DESIGN

The mice were assigned randomly to three groups: the Control group and RC+MY group were given 200 μl of normal saline and 70 mg/kg of myricetin per day, respectively, and the RC and RC+MY groups were free to eat roast chicken breast.

METHODS

We used HPLC to analyze the main types of HCAs in RC. The activity of antioxidant enzymes and expression levels of NF-κB/MAPK signaling pathway in mouse liver were analyzed by biochemical analysis and Western blot. Finally, PPI was used to analyze the correlation between each protein.

RESULTS

Pathological analysis showed that mice treated with RC significantly stimulate liver and colon damage. In addition, western blot analysis showed that MY alleviate RC-induced liver inflammation by inhibiting the NF-κB/MAPK signaling pathway. MY also has a restorative effect on RC-induced colon barrier damage and inflammation. Correlation analysis showed that there was a positive correlation between liver inflammation and intestinal barrier damage.

CONCLUSION

Our findings elucidate the molecular mechanism by which the natural compound MY alleviates RC-induced liver inflammation when included in the daily diet, offering scientific insights for food safety and the development of functional foods.

Myricetin reduces platelet PANoptosis in sepsis to delay disseminated intravascular coagulation

Sepsis is a severe inflammatory disease characterized by cytokine storm, often accompanied by disseminated intravascular coagulation (DIC). PANoptosis is a novel form of cell death triggered by cytokine storms, characterized by a cascade reaction of pyroptosis, apoptosis, and necroptosis. It exists in septic platelets and is closely associated with the onset and progression of DIC. However, there remains an unmet need for drugs targeting PANoptosis. The anti-PANoptosis effect of myricetin was predicted using network pharmacology and confirmed through molecular docking. In vitro platelet activation models demonstrated that myricetin significantly attenuated platelet particle release, integrin activation, adhesion, spreading, clot retraction, and aggregation. Moreover, in a sepsis model, myricetin reduced inflammatory infiltration in lung tissue and platelet activation while improving DIC. Additionally, whole blood sequencing samples from sepsis patients and healthy individuals were analyzed to elucidate the up-regulation of the PANoptosis targets. Our findings demonstrate the inhibitory effect of myricetin on septic platelet PANoptosis, indicating its potential as a novel anti-cellular PANoptosis candidate and therapeutic agent for septic DIC. Furthermore, our study establishes a foundation for utilizing network pharmacology in the discovery of new drugs to treat various diseases.

Synthesis and study of antibiofilm and antivirulence properties of flavonol analogues generated by palladium catalyzed ligand free Suzuki-Miyaura coupling against Pseudomonas aeruginosa PAO1

The Suzuki-Miyaura coupling is one of the ubiquitous method for the carbon-carbon bond-forming reactions in organic chemistry. Its popularity is due to its ability to undergo extensive coupling reactions to generate a broad range of biaryl motifs in a straightforward manner displaying a high level of functional group tolerance. A convenient and efficient synthetic route to arylate different substituted flavonols through the Suzuki-Miyaura cross-coupling reaction has been explained in this study. The arylated products were acquired by the coupling of a variety of aryl boronic acids with flavonols under Pd(OAc)2 catalyzed reaction conditions in a ligand-free reaction strategy. Subsequently, the antibiofilm and antivirulence properties of the arylated flavonols against Pseudomonas aeruginosa PAO1 were studied thoroughly. The best ligands for quorum sensing proteins LasR, RhlR, and PqsR were identified using molecular docking study. These best fitting ligands were then studied for their impact on gene expression level of P. aeruginosa by RT-PCR towards quorum sensing genes lasB, rhlA, and pqsE. The downregulation in the gene expression with the effect of synthesized flavonols endorse the antibiofilm efficiency of the compounds.

Flavones and Related Compounds: Synthesis and Biological Activity

This review focuses on the synthesis and biological activity of flavones and their related flavonoidic compounds, namely flavonols and aurones. Among the biological activities of natural and synthetic flavones and aurones, their anticancer, antioxidant, and antimicrobial properties are highlighted and detailed in this review. Starting from the structures of natural flavones acting on multiple anticancer targets (myricetin, genkwanin, and other structurally related compounds), new flavone analogs were recently designed and evaluated for their anticancer activity. The most representative compounds and their anticancer activity are summarized in this review. Natural flavones recognized for their antimicrobial properties (baicalein, luteolin, quercetol, apigenin, kaempferol, tricin) have been recently derivatized or structurally modulated by chemical synthetic methods in order to obtain new effective antimicrobial flavonoidic derivatives with improved biological properties. The most promising antimicrobial agents are systematically highlighted in this review. The most applied method for the synthesis of flavones and aurones is based on the oxidative cyclization of o-hydroxychalcones. Depending on the reaction conditions and the structure of the precursor, in some cases, several cyclization products result simultaneously: flavones, flavanones, flavonols, and aurones. Based on the literature data and the results obtained by our research group, our aim is to highlight the most promising methods for the synthesis of flavones, as well as the synthetic routes for the other structurally related cyclization products, such as hydroxyflavones and aurones, while considering that, in practice, it is difficult to predict which is the main or exclusive cyclization product of o-hydroxychalcones under certain reaction conditions.