Myricetin-Loaded SBA-15 silica nanoparticles for enhanced management of Pyrexia, pain, and inflammation through modulation of MAPK/NF-kB and COX-2/PGE-2 pathways: Evidence from the biochemical, histological, and metabolomic analysis.

Myricetin (MYR) is a natural flavonoid that has several biological functions. However, some of its beneficial effects are diminished due to low water solubility, stability, and bioavailability. Herein, several kinds of silica nanoparticles, including MCM-41 and SBA-15, were loaded with MYR to improve its biological activity as an analgesic, antipyretic, and anti-inflammatory component, thereby overcoming its drawbacks. The nanoparticles (MYR@SBA-15) were formulated optimally, transforming MYR into an amorphous state. This transformation was confirmed via several strategies, including differential scanning calorimetry, Fourier transform infrared spectroscopy, and powder x-ray diffraction. As a result, there was a significant enhancement in the solubility and rate of dissolution in water. The anti-inflammatory benefits as an innovative strategy and the underlying mechanism of action of MYR and its SBA-15 silica nanoparticles (MYR@SBA-15) were investigated based on the biochemical, histological, immunohistochemical, and metabolomic assays alongside their antipyretic and analgesic characteristics. Compared to the usage of raw MYR, the administration of MYR@SBA-15 at doses of 25, 50, and 100 mg/kg significantly decreases pain perception by inhibiting the body's writhing motions induced by acetic acid. Furthermore, it helps regulate increased body temperature caused by baking yeast and effectively stabilizes it. It reduces the release of NO and PGE2 in a concentration-dependent manner by down-regulating iNOS and COX-2 expression in the inflammatory model. MYR and MYR@SBA-15 also inhibit the nuclear translocation of NF-κB, downregulate the expression of mitogen-activated protein kinases (MAPKs), such as p38, ERK1/2, and JNK protein, and reduce the generation of proinflammatory cytokines, such as TNF-α. In addition, inflammatory cardinal signs like paw edema caused by carrageenan in rats are greatly suppressed by MYR and MYR@SBA-15 treatment when compared to the control group. More noteworthy outcomes are shown in the MYR@SBA-15, particularly at a dose of 100 mg/kg. These results of biochemical and immuno-histochemistry suggest that MYR@SBA-15 may be a useful analgesic antipyretic and may also help reduce inflammation by altering MAPKs/NF-κB and COX-2/PGE2 signaling cascades. Serum metabolomics study demonstrated modifications in various low molecular weight metabolites with arthritis development. These metabolite levels were restored to normal when MYR@SBA-15 was administered via modulating several metabolic pathways, i.e., pyrimidine, energy metabolism, and proteins. Overall, MYR-loaded SBA-15 silica nanoparticles have demonstrated significant promise in enhancing metabolomics and providing a substantial capacity to regulate several oxidative stress and inflammatory mediators.

Myricetin alleviates renal tubular epithelial-mesenchymal transition via NOX4/NF-κB/snail axis in diabetic nephropathy based on network pharmacology analysis.

Diabetic nephropathy (DN), a leading cause of end-stage renal disease, remains a formidable challenge in diabetes management due to the complex nature of its pathogenesis, particularly the epithelial-mesenchymal transition (EMT) process. Our innovative study leverages network pharmacology to explore the therapeutic potentials of Myricetin, a natural flavonoid, focusing on its effects against NOX4, a critical mediator in DN progression. This investigation marks a pioneering approach by integrating network pharmacology to predict and elucidate the inhibitory relationship between Myricetin and NOX4. Utilizing a high-fat diet/streptozotocin (HFD/STZ) induced DN mouse model, we delved into the effects of Myricetin on renal EMT processes. Through network pharmacology analyses coupled with molecular docking studies, we identified and confirmed Myricetin's binding efficacy to NOX4. Extensive in vitro and in vivo experiments further established Myricetin's significant impact on mitigating EMT by modulating the NOX4-NF-κB-Snail signaling pathway. Results from our research demonstrated notable improvements in renal function and reductions in tissue fibrosis among treated HFD/STZ mice. By curtailing NOX4 expression, Myricetin effectively reduced reactive oxygen species (ROS) production, thereby inhibiting NF-κB activation and subsequent Snail expression, crucial steps in the EMT pathway. Supported by both theoretical predictions and empirical validations, this study unveils the mechanism underlying Myricetin's modulation of EMT in DN through disrupting the NOX4-NF-κB-Snail axis. These findings not only contribute a new therapeutic avenue for DN treatment but also underscore the utility of network pharmacology in advancing drug discovery processes.

An Intelligent Hydrogel Platform with Triple-Triggered On-Demand Release for Accelerating Diabetic Wound Healing.

The hydrogel platform with intelligent drug delivery system possesses great potential in the treatment of diabetic wounds. Nevertheless, the intelligent elimination of reactive oxygen species (ROS) remains a formidable challenge in facilitating diabetic wound healing. Herein, a hydrogel platform with triple-triggered on-demand release is constructed to intelligently scavenge ROS and modulate the wound microenvironment to accelerate diabetic wound healing through the release of antioxidative factors. Specifically, the gelatin (Gel) is modified with phenylboronic acid (PBA) to obtain a glucose-sensitive Gel derivative (Gel-BA), which is mixed with oxidized dextran (ODex) and the strong antioxidant myricetin (MY) to swiftly generate a hydrogel platform (OGM). Significantly, the smart release of MY from the hybrid hydrogel under inflammatory conditions intelligently eliminates ROS, effectively alleviating oxidative stress and promoting angiogenic reprogramming of the wound immune microenvironments by activating the Nrf2 pathway. In summary, in vitro and in vivo studies reveal that the OGM hydrogel platform significantly promotes cell proliferation, migration, and tube formation and greatly accelerates diabetic wound healing, offering a local-specific triple-response drug release strategy for the treatment of diabetic wound management.

Enzymatic oxidation increases the antibacterial activity of myricetin against Staphylococcus aureus.

Myricetin (MYR) is a flavonoid with favorable biological activities. In this study, MYR oxidation products (MYRox) were generated through enzymatic oxidation of MYR using horseradish peroxidase. The results showed enzymatic oxidation enhanced the water solubility and antibacterial activity against Staphylococcus aureus (S. aureus) of MYR. Further experiments showed the antibacterial effects of MYRox were conferred by MYR organic phase oxidation products (MYRoo). Both MYR and MYRoo could disrupt the cell membrane integrity, bind to the genomic DNA, affect protein synthesis and degradation, and alter the ROS levels in S. aureus. However, they exerted these effects with different strengths and ways. Finally, MYR or MYRoo can be used as an inhibitor against S. aureus in the cabbage food system, with MYRoo having better effect. This study demonstrated that enzymatic oxidation is an effective approach to improve the water solubility and antibacterial activity of MYR, enhancing its potential application in food preservation.

Removal of polyphenols from anthocyanin-rich extracts using 4-vinylpyridine crosslinked copolymers.

In this work, new sorbents for the purification of anthocyanin-rich extracts were evaluated. Copolymers of 4-vinylpyridine crosslinked with trimethylolpropane trimethacrylate (poly(4VP-co-TRIM)) or 1,4-dimethacryloyloxybenzene (poly(4VP-co-14DMB)) were tested for their potential to capture polyphenols. Copolymers were obtained by seed swelling polymerization in the form of microspheres with permanent porous structure - attractive features of sorbents used for sample purification by dispersive solid phase extraction. The microspheres were characterized by AFM, elemental analysis, SEM, and nitrogen adsorption-desorption method. Their capacity to remove polyphenols was evaluated using spectrophotometry, HPLC-DAD, and LC-MS/MS. For proof-of-concept, the aqueous extracts of berries classified into three different groups regarding their anthocyanin composition (strawberries, raspberries, blackcurrants) were selected. It was found that studied microspheres adsorbed flavonoids more effectively compared to primary secondary amine and graphitized carbon black. Copolymers of 4-vinylpyridine also capture anthocyanins and might be used for the purification of extracts of fruits before LC-MS/MS analysis to reduce the matrix effect.

Interaction of myricetin, ampelopsin (dihydromyricetin), and their sulfate metabolites with serum albumin, cytochrome P450 (CYP2C9, 2C19, and 3A4) enzymes, and organic anion-transporting polypeptides (OATP1B1 and OATP2B1).

Myricetin (MYR) and ampelopsin (AMP, or dihydromyricetin) are flavonoid aglycones found in certain plants and dietary supplements. During the presystemic biotransformation of flavonoids, mainly sulfate and glucuronide derivatives are produced, which are the dominant metabolites in the circulation. In this study, we tested the interactions of MYR, myricetin-3'-O-sulfate (M3'S), AMP, and ampelopsin-4'-O-sulfate (A4'S) with human serum albumin (HSA), cytochrome P450 enzymes (CYPs), and organic anion-transporting polypeptides (OATPs) using in vitro models, including the recently developed method for measuring flavonoid levels in living cells. M3'S and MYR bound to albumin with high affinity, and they showed moderate displacing effects versus the Site I marker warfarin. MYR, M3'S, AMP, and A4'S exerted no or only minor inhibitory effects on CYP2C9, CYP2C19, and CYP3A4 enzymes. M3'S and MYR caused considerable inhibitory actions on OATP1B1 at low micromolar concentrations (IC50 = 1.7 and 6.4 µM, respectively), while even their nanomolar levels resulted in strong inhibitory effects on OATP2B1 (IC50 = 0.3 and 0.4 µM, respectively). In addition, M3'S proved to be a substrate of OATP1B1 and OATP2B1. These results suggest that MYR-containing dietary supplements may affect the OATP-mediated transport of certain drugs, and OATPs are involved in the tissue uptake of M3'S.

Myricetin ameliorates airway inflammation and remodeling in asthma by activating Sirt1 to regulate the JNK/Smad3 pathway.

BACKGROUND: Myricetin has various biological activities and health benefits; however, its effects on airway remodeling in asthma have not been reported. PURPOSE: We aimed to investigate the possibility that myricetin improves airway remodeling by activating Sirt1 and has potential as a new treatment for asthma. METHODS: RAW 264.7 cells were stimulated with lipopolysaccharide and co-cultured with 3T6 cells in vitro to simulate the in vivo effects of inflammation on airway remodeling. Using an ovalbumin-induced chronic asthma mouse model, we compared changes in inflammatory factors and airway remodeling-related factors under treatment with myricetin and/or the Sirt1 inhibitor EX-527 using western blotting and quantitative PCR. Expression plasmids carrying Smad3 site mutations were transfected into 3T6 cells to identify the Sirt1 deacetylation site on Smad3 protein. RESULTS: Myricetin significantly reduced the infiltration of airway inflammatory cells and the production of interleukin (IL)-6 and IL-5, and inhibited mucus secretion by goblet cells, collagen fiber proliferation, and the increase in inflammatory cells in bronchoalveolar lavage fluid from asthmatic mice. Results of in vitro experiments were consistent with those conducted in vivo. Exploring the mechanism of action of myricetin, we found that myricetin downregulated the levels of phosphorylated (p)-JNK, p-Smad3, and acetylated Smad3 proteins by activating Sirt1 both in vivo and in vitro. K341 was identified as the main deacetylation site of Smad3 by myricetin-activated Sirt1. CONCLUSION: Myricetin ameliorates airway inflammation and remodeling in asthma by activating Sirt1 to regulate the JNK/Smad3 pathway.

The selective proapoptotic impact of the myricetin-loaded alginate-cellulose hybrid nanocrystals (MAC-NCs) on the human AGS gastric cancer cells.

BACKGROUND: Myricetin, a flavanol present in fruits, tea, and vegetables, has the potential to reduce chronic diseases like gastric cancer by promoting cell death and stopping cell growth. However, its limited bioactivity due to its short lifespan and poor solubility in water has been a challenge. The current research focuses on incorporating myricetin into alginate-cellulose hybrid nanocrystals to enhance its selective proapoptotic effects on human AGS gastric cancer cells. METHODS: MAC-NCs, myricetin-loaded alginate-cellulose hybrid nanocrystals, were synthesized using a combined co-precipitation/ultrasonic homogenization method and characterized through Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), and Zeta-potential analyses. Their cytotoxic activity was tested on cancerous (AGS) and normal (Huvec) cells, revealing selective toxicity. Apoptotic markers, Caspase 8 and Caspase 9, gene expression was measured, and cell death type was confirmed using DAPI staining and flow cytometry on AGS cells. RESULTS: Synthesized MAC-NCs, measuring 40 nm, showed significant selective toxicity on human gastric cells (IC50 of 31.05 µg/mL) compared to normal endothelial cells (IC50 of 214.26 µg/mL). DAPI and annexin flow cytometry revealed increased apoptotic bodies in gastric cells, indicating apoptosis. However, the apoptosis was found to be independent of Caspase-8 and Caspase-9. CONCLUSION: The current study provides critical insights into the therapeutic potential of MAC-NCs for gastric cancer treatment. Based on the notable induction of apoptosis in the AGS cancer cell line, the synthesized MAC-NCs exhibit promising potential as a selective anti-gastric cancer agent. However, further in-vivo studies are necessary to confirm and quantify the nanoparticle's selective toxicity and pharmaceutical properties in future investigations.

A comparison of different cleaning approaches for blood contamination after curing universal adhesives on the dentine surface.

OBJECTIVE: This study compared the effectiveness of various cleaning approaches, including spray rinsing, repreparing with diamond burs, and using phosphoric acid or sodium hypochlorite alone or with polyphenols (resveratrol or myricetin), in removing blood contamination from the dentine after adhesive light-curing. METHODS: The contact angles of the treated surfaces were measured and scanning electron microscopy/ energy dispersive X-ray spectroscopy observation was performed. The bond strength and nanoleakage were assessed, and in situ zymography was performed before and after aging. Interactions between matrix metalloproteinase (MMP)-9 and polyphenols were evaluated using molecular dynamics and rhMMP-9 inhibition analyses. The destruction of sodium hypochlorite on collagen and the resistance of polyphenols-treated dentine collagen to enzymolysis were evaluated using the hydroxyproline (HYP) assay. The effect of polyphenols on dentine collagen crosslinking was assessed by Fourier Transform Infrared Spectroscopy. RESULTS: The repreparation group had the lowest contact angle compared to the other groups. The spray rinsing group had the lowest bond strength and highest amounts of nanoleakage. Cleaning with phosphoric acid or sodium hypochlorite alone removed the blood contaminants and parts of the adhesive; moreover, applying polyphenols further improved the bond strength and decreased nanoleakage and MMP activity after aging. Both polyphenols inhibited rhMMP-9 activity and promoted collagen crosslinking. Sodium hypochlorite showed the maximum HYP release when used alone, which was decreased after adding polyphenols. SIGNIFICANCE: Phosphoric acid or sodium hypochlorite cleaning can remove blood contamination from the dentine surface after adhesive curing, and the addition of polyphenols can improve the durability of dentine bonding.

Myricetin ameliorates arsenic-induced hematological changes, immune dysfunction, oxidative stress, hepatic and renal injuries and promotes inflammatory genes in rats.

Background: Arsenic (ARS) is a toxic heavy metal that poses a significant concern for both animal and human health. Aim: The study investigated the ameliorative effect of myricetin (MRC) against arsenic-induced immune dysfunction, oxidative stress, hematological changes, hepatic and renal injuries, and inflammatory gene expression in rats. Methods: Rats were divided into 4 groups: the control group (CON) received orally administered distilled water (1 ml/rat), and the ARS group received 10 mg/kg orally, the MRC group received 5 mg of MRC/kg orally, and the co-treated group (ARS+MRC) received 10 mg/kg of ARS and 5 mg/kg b.w. of MRC orally. Results: The results showed that co-treatment of ARS-exposed rats with MRC significantly corrected erythrocyte parameters (except MCV) and leukocyte parameters (except basophils; p < 0.05). Furthermore, the ARS group significantly reduced total proteins and globulins while significantly increasing liver functions and uric acid levels (p < 0.05). Co-administration with MRC significantly mitigated the heart indices (gamma-glutamyl transferase, creatine phosphokinase, CK, lactate dehydrogenase) and lipid dysfunction caused by ARS exposure (p < 0.05). In ARS-exposed rats, there was a significant reduction in antioxidant enzymes and immunoglobulins (IgG and IgM), as well as significantly increased oxidative stress (p < 0.05). The MRC treatment effectively restored the redox status and immune variables that were disrupted by ARS exposure. Serum levels of nitric acid and lysosome were significantly lower, while levels of IL-4, TNF-α, and IFN-γ were higher in the ARS group compared to the other groups (p < 0.05). Immunohistopathology revealed that the expression of Cox2 in kidney and liver tissues varied from mild to moderate in the ARS+MRC group. Furthermore, the ARS-induced upregulation of mRNA levels of inflammatory genes such as IFN-γ, TNF-α, IL-10, and IL-6 in hepatic tissues and MRC significantly attenuated this elevation. These findings suggest that ARS has detrimental effects on blood hematology and health, triggering specific inflammatory genes and indicating the genotoxicity of ARS. However, co-treatment with MYC can mitigate these negative effects. Conclusion: MRC exhibits a significant protective effect against ARS due to its anti-inflammatory and antioxidant properties.

Targeting colorectal cancer using dietary flavonols.

Colorectal cancer is among the well-known forms of cancer and a prominent cause of cancer demises worldwide. In vitro experiments reinforced by animal studies, as well as epidemiological studies of human colorectal cancer propose that the growth of this disease can be moderated by eating aspects. Dietary intake including green vegetables and fruits may result in the reduction of colon cancer chances. The finding suggests that the combinations of dietary nutrients may deliver additive or synergistic effects and might be a powerful method to avoid or eradicate colon cancer beginning and/or development. Flavonols are one of the most widespread dietary nutrients of the polyphenols-flavonoids and major constituent of Allium and Brassicaceae vegetables. Flavonols present in vegetables of Allium and Brassicaceae family are kaempferol, myricetin, quercetin, and isorhamnetin. These flavonols are claimed to have antiproliferative activity in vivo and in vitro against colorectal cancer. The objective of this review is to summarize the role of flavonols obtained from dietary sources in the prevention and treatment of colorectal cancer.

Myricetin mitigates motor disturbance and decreases neuronal ferroptosis in a rat model of Parkinson's disease.

Ferroptosis is an iron-dependent cell death form characterized by reactive oxygen species (ROS) overgeneration and lipid peroxidation. Myricetin, a flavonoid that exists in numerous plants, exhibits potent antioxidant capacity. Given that iron accumulation and ROS-provoked dopaminergic neuron death are the two main pathological hallmarks of Parkinson's disease (PD), we aimed to investigate whether myricetin decreases neuronal death through suppressing ferroptosis. The PD models were established by intraperitoneally injecting 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into rats and by treating SH-SY5Y cells with 1-methyl-4-phenylpyridinium (MPP+), respectively. Ferroptosis was identified by assessing the levels of Fe2+, ROS, malondialdehyde (MDA), and glutathione (GSH). The results demonstrated that myricetin treatment effectively mitigated MPTP-triggered motor impairment, dopamine neuronal death, and α-synuclein (α-Syn) accumulation in PD models. Myricetin also alleviated MPTP-induced ferroptosis, as evidenced by decreased levels of Fe2+, ROS, and MDA and increased levels of GSH in the substantia nigra (SN) and serum in PD models. All these changes were reversed by erastin, a ferroptosis activator. In vitro, myricetin treatment restored SH-SY5Y cell viability and alleviated MPP+-induced SH-SY5Y cell ferroptosis. Mechanistically, myricetin accelerated nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) and subsequent glutathione peroxidase 4 (Gpx4) expression in MPP+-treated SH-SY5Y cells, two critical inhibitors of ferroptosis. Collectively, these data demonstrate that myricetin may be a potential agent for decreasing dopaminergic neuron death by inhibiting ferroptosis in PD.

Metabolomics research on treatment of primary liver cancer with Cortex Juglandis Mandshuricae on LC-MS/MS technology.

Diethylnitrosamine (DEN) was applied to create the primary liver cancer (PLC) animal model. In the study, the normal group, model group, cyclophosphamide (CTX) group, Cortex Juglandis Mandshuricae (CJM) extract group, myricetin group and myricitrin group were divided. LC-MS/MS technology was applied to determine the metabolites of liver tissue samples from different locations (nodular and non-nodular parts of liver tissue) in each group of rats. Through metabolomics research, the connection and difference of anti-PLC induced by the CJM extract, myricetin and myricitrin was analyzed. The surface of the liver tissues of rats in the model group was rough, dimly colored, inelastic, on which there were scattered gray white cancer nodules and blood stasis points. The number of cancer nodules was significantly reduced, and the degree of cell malignancy was low, but there were some inflammatory cell infiltrations, necrosis area and karyokinesis in the CJM extract group, myricetin group, myricitrin group and CTX group. The result of metabolic research indicated that 45 potential biomarkers of the PLC were found, as gamma-aminoisobutyrate, taurochenodeoxycholate, xanthurenic acid, etc. There were 22 differential metabolites in the CTX group, 16 differential metabolites in the CJM extract group, 14 differential metabolites in the myricetin group, 14 differential metabolites in the myricitrin group.

Myricetin inhibits transmissible gastroenteritis virus replication by targeting papain-like protease deubiquitinating enzyme activity.

Myricetin, a natural flavonoid found in various foods, was investigated for its antiviral effect against transmissible gastroenteritis virus (TGEV). This α-coronavirus causes significant economic losses in the global swine industry. The study focused on the papain-like protease (PLpro), which plays a crucial role in coronavirus immune evasion by mediating deubiquitination. Targeting PLpro could potentially disrupt viral replication and enhance antiviral responses. The results demonstrated that myricetin effectively inhibited TGEV-induced cytopathic effects in a dose-dependent manner, with an EC50 value of 31.19 µM. Myricetin significantly reduced TGEV viral load within 48 h after an 8-h co-incubation period. Further investigations revealed that myricetin at a concentration of 100 µM directly inactivated TGEV and suppressed its intracellular replication stage. Moreover, pretreatment with 100 µM myricetin conferred a protective effect on PK-15 cells against TGEV infection. Myricetin competitively inhibited PLpro with an IC50 value of 6.563 µM. Molecular docking experiments show that myricetin binds to the Cys102 residue of PLpro through conventional hydrogen bonds, Pi-sulfur, and Pi-alkyl interactions. This binding was confirmed through site-directed mutagenesis experiments, indicating myricetin as a potential candidate for preventing and treating TGEV infection.

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.

Myricetin Restores Autophagy to Attenuate Lumbar Intervertebral Disk Degeneration Via Negative Regulation of the JAK2/STAT3 Pathway.

Autophagy is a critical player in lumbar intervertebral disk degeneration (IDD), and autophagy activation has been suggested to prevent the apoptosis of nucleus pulposus cells (NPCs). Myricetin has anti-cancer, anti-inflammatory, and antioxidant potentials and can activate autophagy. Thus, this study focused on the roles and mechanisms of myricetin in IDD. A puncture-induced rat IDD model was established and intraperitoneally injected with 20-mg/kg/day myricetin. Histopathological changes of intervertebral disks (IVDs) were assessed by hematoxylin and eosin staining and Safranin O/Fast Green staining. The isolated NPCs from IVDs of healthy rats were stimulated with IL-1ß to mimic IDD-like conditions. The roles of myricetin in cell apoptosis, extracellular matrix (ECM) degradation, autophagy repression, and the JAK2/STAT3 pathway activation were examined by cell counting kit-8, flow cytometry, western blotting, real-time quantitative polymerase chain reaction, and immunofluorescence staining. Myricetin treatment attenuated the apoptosis and ECM degradation, and enhanced autophagy in the IL-1ß-treated NPCs, whereas the myricetin-mediated protection was limited by autophagy inhibition. Mechanistically, myricetin activated autophagy through blocking the JAK2/STAT3 signaling. In vivo experiments revealed that intraperitoneal injection of myricetin activated NPC autophagy to relieve puncture injury in rats. Myricetin prevents IDD by attenuating NPC apoptosis and ECM degradation through blocking the JAK2/STAT3 pathway to enhance autophagy.

Myricetin ameliorates cognitive impairment in 3×Tg Alzheimer's disease mice by regulating oxidative stress and tau hyperphosphorylation.

BACKGROUND: Alzheimer's disease is characterized by abnormal ß-amyloid (Aß) plaque accumulation, tau hyperphosphorylation, reactive oxidative stress, mitochondrial dysfunction and synaptic loss. Myricetin, a dietary flavonoid, has been shown to exert neuroprotective effects in vitro and in vivo. Here, we aimed to elucidate the mechanism and pathways involved in the protective effect of myricetin. METHODS: The effect of myricetin was assessed on Aß42 oligomer-treated neuronal SH-SY5Y cells and in 3×Tg mice. Behavioral tests were performed to assess the cognitive effects of myricetin (14 days, ip) in 3×Tg mice. The levels of beta-amyloid precursor protein (APP), synaptic and mitochondrial proteins, glycogen synthase kinase3ß (GSK3ß) and extracellular regulated kinase (ERK) 2 were assessed via Western blotting. Flow cytometry assays, immunofluorescence staining, and transmission electron microscopy were used to assess mitochondrial dysfunction and reactive oxidative stress. RESULTS: We found that, compared with control treatment, myricetin treatment improved spatial cognition and learning and memory in 3×Tg mice. Myricetin ameliorated tau phosphorylation and the reduction in pre- and postsynaptic proteins in Aß42 oligomer-treated neuronal SH-SY5Y cells and in 3×Tg mice. In addition, myricetin reduced reactive oxygen species generation, lipid peroxidation, and DNA oxidation, and rescued mitochondrial dysfunction via the associated GSK3ß and ERK 2 signalling pathways. CONCLUSIONS: This study provides new insight into the neuroprotective mechanism of myricetin in vitro in cell culture and in vivo in a mouse model of Alzheimer's disease.

Effects of myricetin and its derivatives on nonenzymatic glycation: A mechanism study based on proteomic modification and fluorescence spectroscopy analysis.

Myricetin and its derivatives, myricitrin and dihydromyricetin, are flavonoids widely presented in foods and phytomedicine that possess tremendous health potential. In this study, we compared the antiglycation activity of myricetin and its derivatives, then investigated the underlying mechanism using proteomic modification and fluorescence spectroscopy analysis. All three compounds exhibited thorough inhibition on nonenzymatic glycation process, with the inhibitory effects on AGEs reaching 85% at 40 µmol/L. They effectively protected bovine serum albumin (BSA) structure by inhibiting protein oxidation, preventing the conversion from α-helix to ß-sheet, and reducing amyloid-like cross-ß structure formation. Among the three compounds, myricetin showed a predominant antiglycation activity. Proteomic analysis identified the early glycated sites that were protected by myricetin, including lysine K235, 256, 336, 421, 420, 489, etc. Additionally, fluorescence spectroscopy revealed spontaneous interactions between BSA and myricetin. Overall, myricetin holds promise as an antiglycation agent in both the food and drug industries.

Efficient and novel biosynthesis of myricetin α-triglucoside with improved solubility using amylosucrase from Deinococcus deserti.

Although myricetin (3,3',4',5,5',7-hexahydroxyflavone, MYR) has a high antioxidant capacity and health functions, its use as a functional food material is limited owing to its low stability and water solubility. Amylosucrase (ASase) is capable of biosynthesizing flavonol α-glycoside using flavonols as acceptor molecules and sucrose as a donor molecule. Here, ASase from Deinococcus deserti (DdAS) efficiently biosynthesizes a novel MYR α-triglucoside (MYRαG3) using MYR as the acceptor molecule. Comparative homology analysis and computational simulation revealed that DdAS has a different active pocket for the transglycosylation reaction. DdAS produced MYRαG3 with a conversion efficiency of 67.4 % using 10 mM MYR and 50 mM sucrose as acceptor and donor molecules, respectively. The structure of MYRαG3 was identified as MYR 4'-O-4″,6″-tri-O-α-D-glucopyranoside using NMR and LC-MS. In silico analysis confirmed that DdAS has a distinct active pocket compared to other ASases. In addition, molecular docking simulations predicted the synthetic sequence of MYRαG3. Furthermore, MYRαG3 showed a similar DPPH radical scavenging activity of 49 %, comparable to MYR, but with significantly higher water solubility, which increased from 0.03 µg/mL to 511.5 mg/mL. In conclusion, this study demonstrated the efficient biosynthesis of a novel MYRαG3 using DdAS and highlighted the potential of MYRαG3 as a functional material.