Treatment with a combination of myricitrin and exercise alleviates myocardial infarction in rats via suppressing Nrf2/HO-1 antioxidant pathway.

Myocardial infarction (MI) is the primary source of death in cardiovascular diseases. Myricitrin (MYR) is a phenolic compound known for its antioxidant properties. This study aimed to investigate the impact of MYR alone or combined with exercise on a rat model of MI and its underlying mechanism. Sprague-Dawley rats were randomized into 5 groups: sham-operated (Sham), MI-sedentary (MI-Sed), MI-exercise (MI-Ex), MI-sedentary + MYR (MI-Sed-MYR) and MI-exercise + MYR (MI-Ex-MYR). MI was induced through ligation of left anterior descending coronary artery. The treatment with exercise or MYR (30 mg/kg/d) gavage began one week after surgery, either individually or in combination. After 8 weeks, the rats were assessed for cardiac function. Myocardial injuries were estimated using triphenyltetrazolium chloride, sirius red and Masson staining. Changes in reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm), apoptosis and Nrf2/HO-1 pathway were analyzed by ROS kit, JC-1 kit, TUNEL assay, Western blot and immunohistochemistry. Both MYR and exercise treatments improved cardiac function, reduced infarct size, suppressed collagen deposition, and decreased myocardial fibrosis. Additionally, both MYR and exercise treatments lowered ROS production induced by MI, restored ΔΨm, and attenuated oxidative stress and apoptosis in cardiomyocytes. Importantly, the combination of MYR and exercise showed greater efficacy compared to individual treatments. Mechanistically, the combined intervention activated the Nrf2/HO-1 signaling pathway. These findings suggest that the synergistic effect of MYR and exercise may offer a promising therapeutic approach for alleviating MI.

Diospyros lotus leaf extract and its main component myricitrin inhibit itch­related IL­6 and IL­31 by suppressing microglial inflammation and microglial­mediated astrocyte activation.

Diospyros lotus has been traditionally used in Asia for medicinal purposes, exhibiting a broad spectrum of pharmacological effects including antioxidant, neuroprotective and anti­inflammatory properties. While the anti­itch effect of D. lotus leaves has been reported, studies on the detailed mechanism of action in microglia and astrocytes, which are members of the central nervous system, have yet to be revealed. The present study aimed to investigate effects of D. lotus leaf extract (DLE) and its main component myricitrin (MC) on itch­related cytokines and signaling pathways in lipopolysaccharide (LPS)­stimulated microglia. The effect of DLE and MC on activation of astrocyte stimulated by microglia was also examined. Cytokine production was evaluated through reverse transcription PCR and western blot analysis. Signaling pathway was analyzed by performing western blotting and immunofluorescence staining. The effect of microglia on astrocytes activation was evaluated via western blotting for receptors, signaling molecules and itch mediators and confirmed through gene silencing using short interfering RNA. DLE and MC suppressed the production of itch­related cytokine IL­6 and IL­31 in LPS­stimulated microglia. These inhibitory effects were mediated through the blockade of NF­κB, MAPK and JAK/STAT pathways. In astrocytes, stimulation by microglia promoted the expression of itch­related molecules such as oncostatin M receptor, interleukin 31 receptor a, inositol 1,4,5­trisphosphate receptor 1, lipocalin­2 (LCN2), STAT3 and glial fibrillary acidic protein. However, DLE and MC significantly inhibited these receptors. Additionally, astrocytes stimulated by microglia with IL­6, IL­31, or both genes silenced did not show activation of LCN2 or STAT3. The findings of the present study demonstrated that DLE and MC could suppress pruritic activity in astrocytes induced by microglia­derived IL­6 and IL­31. This suggested the potential of DLE and MC as functional materials capable of alleviating pruritus.

Sedum kamtschaticum Exerts Hypnotic Effects via the Adenosine A2A Receptor in Mice.

Insomnia is a common sleep disorder with significant societal and economic impacts. Current pharmacotherapies for insomnia are often accompanied by side effects, necessitating the development of new therapeutic drugs. In this study, the hypnotic effects and mechanisms of Sedum kamtschaticum 30% ethanol extract (ESK) and one of its active compounds, myricitrin, were investigated using pentobarbital-induced sleep experiments, immunohistochemistry (IHC), receptor binding assays, and enzyme-linked immunosorbent assay (ELISA). The pentobarbital-induced sleep experiments revealed that ESK and myricitrin reduced sleep latency and prolonged total sleep time in a dose-dependent manner. Based on c-Fos immunostaining, ESK, and myricitrin enhanced the GABAergic neural activity in sleep-promoting ventrolateral preoptic nucleus (VLPO) GABAergic. By measuring the level of GABA released from VLPO GABAergic neurons, ESK and myricitrin were found to increase GABA release in the hypothalamus. These effects were significantly inhibited by SCH. Moreover, ESK exhibited a concentration-dependent binding affinity for the adenosine A2A receptors (A2AR). In conclusion, ESK and myricitrin have hypnotic effects, and their underlying mechanisms may be related to the activation of A2AR.

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.

Novel insights into the molecular mechanisms underlying anti-nociceptive effect of myricitrin against reserpine-induced fibromyalgia model in rats: Implication of SIRT1 and miRNAs.

ETHNOPHARMACOLOGICAL RELEVANCE: Manilkara zapota (L.) P. Royen, also termed sapodilla or chikoo, is a significant plant in ethnomedicine because of its long history of traditional medical applications. In diverse cultures, sapodilla is believed to protect against oxidative stress, inflammation, and some chronic diseases because of its high antioxidant content. The naturally occurring antioxidant myricitrin (MYR) flavonoid is primarily found in the leaves and other plant parts of sapodilla and it is well-known for having therapeutic qualities and possible health advantages. AIM OF THE STUDY: To appraise the possible impact of MYR on a rat model of reserpine-induced fibromyalgia (FM) and explore its mechanism of action. MATERIALS AND METHODS: Isolation and identification of MYR with more than 99% purity from Manilkara zapota leaves were primarily done and confirmed through chromatographic and spectrophotometric techniques. To develop FM model, reserpine (RSP) was injected daily (1 mg/kg, s.c.) for three successive days. Then, MYR (10 mg/kg, i.p.) and pregabalin (PGB, 30 mg/kg, p.o.) were given daily for another five days. Behavioral changes were assessed through open field test (OFT), hot plate test, and forced swimming test (FST). Further analyses of different brain parameters and signaling pathways were performed to assess monoamines levels, oxidative stress, inflammatory response, apoptotic changes as well as silent information regulator 1 (SIRT1) and micro RNAs (miRNAs) expressions. RESULTS: From High-Performance Liquid Chromatography (HPLC) analysis, the methanol extract of sapodilla leaves contains 166.17 µg/ml of MYR. Results of behavioral tests showed a significant improvement in RSP-induced nociceptive stimulation, reduced locomotion and exploration and depressive-like behavior by MYR. Biochemical analyses showed that MYR significantly ameliorated the RSP-induced imbalance in brain monoamine neurotransmitters. In addition, MYR significantly attenuated oxidative stress elicited by RSP via up-regulating nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) protein expressions, enhancing superoxide dismutase (SOD) and catalase (CAT) activities, and reducing malondialdehyde (MDA) content in brain. The RSP-provoked inflammatory response was also diminished by MYR treatment as shown by a significant decreased NOD-like receptor protein 3 (NLRP3) inflammasome expression along with reduced levels of interleukin 1 beta (IL-1ß) and nuclear factor-κB (NF-κB). Furthermore, the anti-apoptotic activity of MYR was demonstrated by a marked rise in Bcl-2-associated X protein (BAX)/B cell lymphoma-2 (Bcl-2) ratio by lowering Bcl-2 while increasing BAX levels. In addition, MYR treatment significantly boosted the expression of SIRT1 deacetylase in RSP-treated animals. Interestingly, molecular docking showed the ability of MYR to form a stable complex in the binding site of SIRT1. Regarding miRNAs, MYR effectively ameliorated RSP-induced changes in miR-320 and miR-107 gene expressions. CONCLUSION: Our findings afford new insights into the anti-nociceptive profile of MYR in the RSP-induced FM model in rats. The underlying mechanisms involved direct binding and activation of SIRT1 to influence different signaling cascades, including Nrf2 and NF-κB/NLRP3 together with modulation of miRNAs. However, more in-depth studies are needed before proposing MYR as a new clinically relevant drug in the management of FM.

Myricitrin inhibited ferritinophagy-mediated ferroptosis in cisplatin-induced human renal tubular epithelial cell injury.

Cisplatin-induced acute kidney injury (AKI) increases the patient mortality dramatically and results in an unfavorable prognosis. A strong correlation between AKI and ferroptosis, which is a notable type of programmed cell death, was found in recent studies. Myricitrin is a natural flavonoid compound with diverse pharmacological properties. To investigate the protective effect of myricitrin against cisplatin induced human tubular epithelium (HK-2) cell injury and the underlying anti-ferroptic mechanism by this study. Firstly, a pharmacology network analysis was proposed to explore the myricitrin's effect. HK-2 cells were employed for in vitro experiments. Ferroptosis was detected by cell viability, quantification of iron, malondialdehyde, glutathione, lipid peroxidation fluorescence, and glutathione peroxidase (GPX4) expression. Ferritinophagy was detected by related protein expression (NCOA4, FTH, LC3II/I, and SQSTM1). In our study, GO enrichment presented that myricitrin might be effective in eliminating ferroptosis. The phenomenon of ferroptosis regulated by ferritinophagy was observed in cisplatin-activated HK-2 cells. Meanwhile, pretreatment with myricitrin significantly rescued HK-2 cells from cell death, reduced iron overload and lipid peroxidation biomarkers, and improved GPX4 expression. In addition, myricitrin downregulated the expression of LC3II/LC3I and NCOA4 and elevated the expression of FTH and SQTM. Furthermore, myricitrin inhibited ROS production and preserved mitochondrial function with a lower percentage of green JC-1 monomers. However, the protection could be reserved by the inducer of ferritinophagy rapamycin. Mechanically, the Hub genes analysis reveals that AKT and NF-κB are indispensable mediators in the anti-ferroptic process. In conclusion, myricitrin ameliorates cisplatin induced HK-2 cells damage by attenuating ferritinophagy mediated ferroptosis.

Kinetics of Flavonoid Degradation and Controlled Release from Functionalized Magnetic Nanoparticles.

Flavonoids are naturally occurring antioxidants that have been shown to protect cell membranes from oxidative stress and have a potential use in photodynamic cancer treatment. However, they degrade at physiological pH values, which is often neglected in drug release studies. Kinetic study of flavonoid oxidation can help to understand the mechanism of degradation and to correctly analyze flavonoid release data. Additionally, the incorporation of flavonoids into magnetic nanocarriers can be utilized to mitigate degradation and overcome their low solubility, while the release can be controlled using magnetic fields (MFs). An approach that combines alternating least squares (ALS) and multilinear regression to consider flavonoid autoxidation in release studies is presented. This approach can be used in general cases to account for the degradation of unstable drugs released from nanoparticles. The oxidation of quercetin, myricetin (MCE), and myricitrin (MCI) was studied in PBS buffer (pH = 7.4) using UV-vis spectrophotometry. ALS was used to determine the kinetic profiles and characteristic spectra, which were used to analyze UV-vis data of release from functionalized magnetic nanoparticles (MNPs). MNPs were selected for their unique magnetic properties, which can be exploited for both targeted drug delivery and control over the drug release. MNPs were prepared and characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, superconducting quantum interference device magnetometer, and electrophoretic mobility measurements. Autoxidation of all three flavonoids follows a two-step first-order kinetic model. MCE showed the fastest degradation, while the oxidation of MCI was the slowest. The flavonoids were successfully loaded into the prepared MNPs, and the drug release was described by the first-order and Korsmeyer-Peppas models. External MFs were utilized to control the release mechanism and the cumulative mass of the flavonoids released.

Myricitrin from bayberry as a potential inhibitor of cathepsin-D: Prospects for squamous lung carcinoma prevention.

Cathepsin-D (CATD) inhibitors' design and development drawn interest due to their potential therapeutic applications in managing different cancer types, including lung cancer. This study investigated myricitrin, a flavonol-3-O-rhamnoside, for its binding affinity to CATD. Molecular docking experiments revealed a strong binding affinity (-7.8 kcal/mol). Molecular dynamics (MD) simulation confirmed the complex's stability, while enzyme activity studies showed inhibitory concentration (IC50) of 35.14 ± 6.08 µM (in cell-free) and 16.00 ± 3.48 µM (in cell-based) test systems. Expression analysis indicated downregulation of CATD with a fold change of 1.35. Myricitrin demonstrated antiproliferative effects on NCIH-520 cells [IC50: 64.11 µM in Sulphorhodamine B (SRB), 24.44 µM in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)], but did not affect healthy CHANG cells. It also prolonged the G2/M phase (at 10 µM: 1.19-fold; at 100 µM: 1.13-fold) and increased sub-diploid population by 1.35-fold. Based on the analysis done using SwissADME program, it is predicted that myricitrin is not a cytochrome p450s (CYPs) inhibitor, followed the rule of Ghose and found not permeable to the blood-brain barrier (BBB) which suggests it as a safe molecule. In summary, the experimental findings may establish the foundation for myricitrin and its analogues to be used therapeutically in CATD-mediated lung cancer prevention.

Myricitrin versus EGCG in the Treatment of Obesity: Target Mining and Molecular Mechanism Exploring based on Network Pharmacology.

BACKGROUND: Myricitrin is a flavonol glycoside possessing beneficial effects on obesity, a rising global health issue that affects millions of people worldwide. However, the involving target and mechanism remain unclear. OBJECTIVE: In the present study, the anti-obesity targets and molecular mechanisms of Myricitrin, along with another flavanol Epigallocatechin gallate (EGCG), were explored through network pharmacology, bioinformatics, and molecular docking. METHODS: The potential targets for Myricitrin and EGCG were obtained from Pharmmaper, SwissTargetPrediction, TargetNet, SEA, Super-PRED, TCMSP, and STICH databases. Meanwhile, DEG targets were retrieved from GEO datasets, and obesity targets were collected from DrugBank, TTD, DisGeNet, OMIM, GeneCards, PharmGKB, and CTD databases. GO and KEGG pathway enrichment analyses were conducted through Metascape online tool. Protein-protein interaction (PPI) networks were also constructed for compound, DEG, and obesity targets to screen the core targets through MCODE analysis. The further screened-out key targets were finally verified through the compound-target-pathway-disease network, mRNA expression level, target-organ correlation, and molecular docking analyses. RESULTS: In total, 538 and 660 targets were identified for Myricitrin and EGCG, respectively, and 725 DEG targets and 1880 obesity targets were retrieved. GO and KEGG analysis revealed that Myricitrin and EGCG targets were enriched in the pathways correlating with obesity, cancer, diabetes, and cardiovascular disease. Furthermore, the intersection core targets for Myricitrin and EGCG function mainly through the regulation of responses to hormones and involving pathways in cancer. Above all, androgen receptor (AR), cyclin D1 (CCND1), early growth response protein 1 (EGR1), and estrogen receptor (ERS1) were identified as key targets in the compound-target-pathway-disease network for both Myricitrin and EGCG, with significant different mRNA expression between weight loss and control groups. Target-organ correlation analysis exhibited that AR and CCND1 showed high expression in adipocytes. Molecular docking also revealed good binding abilities between Myricitrin and EGCG, and all four receptor proteins. CONCLUSION: The present research integrated network pharmacology and bioinformatics approach to reveal the key targets of Myricitrin and EGCG against obesity. The results provided novel insights into the molecular mechanism of Myricitrin and EGCG in obesity prevention and treatment and laid the foundations for the exploitation of flavonoid-containing herbal resources.

Validation of stability-indicating LC method, degradation study, and impact on antioxidant and antifungal activities of Eugenia uniflora leaves extract.

The aim of this study is to demonstrate the stability-indicating capacity of an analytical method for Eugenia uniflora, enhance understanding of the stability of myricitrin, and assess the effect of degradation of spray-dried extract (SDE) on antioxidant and antifungal activities. Validation of the stability-indicating method was carried out through a forced degradation study of SDE and standard myricitrin. The antioxidant and antifungal activities of SDE were evaluated both before and after degradation. The quantification method described was found to be both accurate and precise in measuring myricitrin levels in SDE from E. uniflora, with excellent selectivity that confirmed its stability-indicating capability. The forced degradation study revealed that the marker myricitrin is sensitive to hydrolysis, but generally stable under other stress conditions. By contrast, the standard myricitrin displayed greater susceptibility to degradation under forced degradation conditions. Analysis of the antioxidant activity of SDE before and after degradation showed a negative impact in this activity due to degradation, while no significant effect was observed on antifungal activity. The method described can be a valuable tool in the quality control of E. uniflora, and the findings can assist in determining the optimal conditions and storage of products derived from this species.

Toward the bioactive potential of myricitrin in food production: state-of-the-art green extraction and trends in biosynthesis.

Myricitrin is a member of flavonols, natural phenolic compounds extracted from plant resources. It has gained great attention for various biological activities, such as anti-inflammatory, anti-cancer, anti-diabetic, as well as cardio-/neuro-/hepatoprotective activities. These effects have been demonstrated in both in vitro and in vivo models, making myricitrin a favorable candidate for the exploitation of novel functional foods with potential protective or preventive effects against diseases. This review summarized the health benefits of myricitrin and attempted to uncover its action mechanism, expecting to provide a theoretical basis for their application. Despite enormous bioactive potential of myricitrin, low production, high cost, and environmental damage caused by extracting it from plant resources greatly constrain its practical application. Fortunately, innovative, green, and sustainable extraction techniques are emerging to extract myricitrin, which function as alternatives to conventional techniques. Additionally, biosynthesis based on synthetic biology plays an essential role in industrial-scale manufacturing, which has not been reported for myricitrin exclusively. The construction of microbial cell factories is absolutely an appealing and competitive option to produce myricitrin in large-scale manufacturing. Consequently, state-of-the-art green extraction techniques and trends in biosynthesis were reviewed and discussed to endow an innovative perspective for the large-scale production of myricitrin.

The effects of myricitrin and chebulinic acid on the rat hippocampus exposed to gamma radiation: A stereological, histochemical and biochemical study.

AIM: Gamma radiation, a form of ionizing radiation, is used in many different areas, especially in the health field and in the treatment of cancer. However, gamma radiation used for therapeutic purposes also has numerous harmful effects on human health. This study was planned to investigate the impacts of exposure to gamma radiation on the hippocampal area and the preventive effects of myricitrin and chebulinic acid against that damage. MATERIAL AND METHOD: Thirty-six male Wistar albino rats were randomly divided into six groups. The control group was exposed to no treatment. The chebulinic acid and myricitrin groups were injected with the relevant drug at a dosage of 0.033 mg/kg) (vehicle; normal saline) per day. The gamma groups were placed in a plexiglass test setup with their heads positioned close to the source. The subjects were exposed to radiation with a mixed source containing radioactive Cs-137 and Co-60 isotopes obtained from Ondokuz Mayis University Physics Department Nuclear Physics Laboratory for 1 h. Gamma radiation was applied 16 mGy for one hour per day for 10 days. The gamma radiation+chebulinic acid and the gamma radiation myricitrin groups also received 0.033 mg/kg per day of these drugs via injection. Immediately after the experimental procedure, all animals were subjected to behavioural tests, and perfused brain tissues were analyzed using stereological methods. RESULTS: Stereological analysis showed that gamma radiation caused a decrease in the numbers of neurons in the hippocampal area (p < 0.01; One-way ANOVA) and that chebulinic acid and myricitrin reduced this decrease (p < 0.01; One-way ANOVA). Decreases in learning and memory capacity were detected in behavioural tests in rats from the Gamma group. CONCLUSION: The study findings showed that that the adverse health effects of Gamma radiation can be ameliorated using myricitrin and chebulinic acid. Myricitrin was more effective in terms of cell proliferation and defence against oxidative stress than chebulinic acid, and exhibited a more neuroprotective effect. However, more detailed analyses should be performed before using either antioxidant for therapeutic purposes.

Myricitrin: A promising herbal therapy for periodontitis in immunosuppressed status.

Background: Periodontitis is a complex chronic inflammatory disease aggravated in immunosuppressed patients. However, adjuvant therapies can alleviate severe inflammation and slow down disease progression. Objective: To evaluate the efficacy of myricitrin, a herbal flavonoid glycoside, in reducing immunosuppression-associated periodontitis and compare its effects with that of alendronate on alveolar bone regeneration. Methods: Fifty albino Wistar rats were randomly allocated to the control, periodontitis, immunosuppressant, myricitrin, and alendronate groups. Ligature-associated periodontitis was induced in all groups, except the control group. Cyclosporin A (CsA) was administered subcutaneously in the immunosuppressant group for immunosuppression. The myricitrin group received CsA and myricitrin, whereas the alendronate group received CsA and alendronate. The therapeutic efficacies of myricitrin and alendronate were compared histologically, morphometrically, and biochemically. Results: Myricitrin reversed bone destruction in the periodontitis and immunosuppressant groups. Morphometrically, myricitrin showed comparable improvements to alendronate in terms of gaining more bone area to 49.4 ± 4.6 and 59.5 ± 2%, respectively (P < 0.001 in relation to the untreated periodontitis group). Concomitantly, myricitrin increased osteoblast count significantly to 28.4 ± 4.7 closer to the 34.5 ± 2.4 count in the alendronate group (P < 0.001 compared with 22.5 ± 2.6 count of the immunosuppressant group). Moreover, myricitrin restored the serum calcium to 9.4 ± 0.6 mg/dL and alkaline phosphatase up to 112.9 ± 2.9 IU/L, which were almost normal levels similar to the control cohort (P > 0.05). Conclusion: Myricitrin showed beneficial effects in counteracting bone resorption in subjects with immunosuppression-associated periodontitis. Its efficacy in slowing down disease progression was comparable to that of alendronate.

Diospyros lotus leaf extract and its main component myricitrin regulate pruritus through the inhibition of astrocyte activation.

Diospyros lotus is a deciduous plant native to Asian countries, including Korea, Japan and China, and southeast Europe. In traditional medicine, Diospyros lotus is used as an anticancer, antidiabetic and antipyretic agent. The present study aimed to evaluate the effect of Diospyros lotus leaf extract (DLE) in ameliorating histamine-independent pruritus. Activation of signal transducer and activator of transcription 3 (STAT3) in astrocytes contributes to pruritus. In this study, the effects of DLE and its main component, myricetin (MC), on the activation of STAT3, expression of glial fibrillary acidic protein (GFAP), and production of lipocalin-2 (LCN2) in IL-6-treated astrocytes and chloroquine-injected mice were investigated through western blot, reverse transcription-quantitative PCR, and immunofluorescence staining. DLE and MC inhibited STAT3 activation, GFAP expression and LCN2 release via inositol 1,4,5-trisphosphate receptor type 1 blockade in astrocytes. DLE and MC ameliorated scratching behavior, expression of GFAP, mast cell infiltration and serum IL-6 levels in chloroquine-injected mice. These results suggested that DLE and MC can be used as oral therapeutic agents for the treatment and management of pruritus.

Myricitrin promotes osteogenesis and prevents ovariectomy bone mass loss via the PI3K/AKT signalling pathway.

This study aimed to explore the effect of myricitrin on osteoblast differentiation in mice immortalised bone marrow mesenchymal stem cells (imBMSCs). Additionally, ovariectomy (OVX) mice were employed to examine the effect of myricitrin on bone trabecular loss in vivo. The effect of myricitrin on the proliferation of imBMSCs was evaluated using a cell counting kit-8 assay. Alizarin red staining, alkaline phosphatase staining were performed to elucidate osteogenesis. Furthermore, qRT-PCR and western blot determined the expression of osteo-specific genes and proteins. To screen for candidate targets, mRNA transcriptome genes were sequenced using bioinformatics analyses. Western blot and molecular docking analysis were used to examine target signalling markers. Moreover, rescue experiments were used to confirm the effect of myricitrin on the osteogenic differentiation of imBMSCs. OVX mice were also used to estimate the delay capability of myricitrin on bone trabecular loss in vivo using western blot, micro-CT, tartaric acid phosphatase (Trap) staining, haematoxylin and eosin staining, Masson staining and immunochemistry. In vitro, myricitrin significantly enhanced osteo-specific genes and protein expression and calcium deposition. Moreover, mRNA transcriptome gene sequencing and molecular docking analysis revealed that this enhancement was accompanied by an upregulation of the PI3K/AKT signalling pathway. Furthermore, copanlisib, a PI3K inhibitor, partially reversed the osteogenesis promotion induced by myricitrin. In vivo, western blot, micro-CT, hematoxylin and eosin staining, Masson staining, Trap staining and immunochemistry revealed that bone trabecular loss rate was significantly alleviated in the myricitrin low- and high-dose groups, with an increased expression of osteopontin, osteoprotegerin, p-PI3K and p-AKT compared to the OVX group. Myricitrin enhances imBMSC osteoblast differentiation and attenuate bone mass loss partly through the upregulation of the PI3K/AKT signalling pathway. Thus, myricitrin has therapeutic potential as an antiosteoporosis drug.

Hepatoprotective role of myricitrin isolated from Mimusops elengi Linn. leaves extract on γ-radiation-induced liver damage in rats: Phyto-biochemical investigations.

The hepatoprotective effects of methanol extract of Mimusops elengi Linn. (M. elengi L.) leaves and isolated pure myricitrin (3-, 4-, 5-, 5, 7-five hydroxyflavone-3-O-α-l-rhamnoside) (Myr) were evaluated in male rats exposed to γ-irradiation. The extraction of M. elengi L. leaves was performed using ethyl acetate (EtOAC). Seven groups of rats were used: control group, irradiated (IRR) group (6 Gy of γ-rays in a single dose), vehicle group (oral administration of 0.5% carboxymethyl cellulose for 10 days), EtOAC extract group (100 mg/kg body weight of extract, orally for 10 days), EtOAC + IRR group (administration of extract and exposure to γ-rays on Day 7), Myr group (50 mg/kg body weight Myr, orally for 10 days), and Myr + IRR group (administration of Myr and exposure to γ-rays on Day 7). High-performance liquid chromatography and 1H-nuclear magnetic resonance were used to isolate and characterize the compounds from M. elengi L. leaves. Enzyme-linked immunosorbent assay was used for biochemical analyses. Identified compounds were Myr, myricetin 3-O-galactoside, myricetin 3-O-rahmnopyranoside (1 → 6) glucopyranoside, quercetin, quercitol, gallic acid, α-,ß-amyrin, ursolic acid, and lupeol. Serum aspartate transaminase and alanine transaminase activities were significantly increased, while serum protein and albumin levels were significantly decreased after irradiation. Hepatic levels of tumor necrosis factor-α, prostaglandin 2, inducible nitric oxide synthase, interleukin-6 (IL-6), and IL-12 were increased following irradiation. Improvements were observed in most serological parameters after treatment with extract or pure Myr, with histological analyses confirming decreased liver injury in treated rats. Our study demonstrates that pure Myr has a greater hepatoprotective effect than M. elengi leaf extracts against irradiation-induced hepatic inflammation.

A Study on the Interactions of Proteinase K with Myricetin and Myricitrin by Multi-Spectroscopy and Molecular Modeling.

Myricetin (MYR) and myricitrin (MYT) are well recognized for their nutraceutical value, such as antioxidant, hypoglycemic, and hypotensive effects. In this work, fluorescence spectroscopy and molecular modeling were adopted to investigate the conformational and stability changes of proteinase K (PK) in the presence of MYR and MYT. The experimental results showed that both MYR and MYT could quench fluorescence emission via a static quenching mechanism. Further investigation demonstrated that both hydrogen bonding and van der Waals forces play significant roles in the binding of complexes, which is consistent with the conclusions of molecular modeling. Synchronous fluorescence spectroscopy, Förster resonance energy transfer, and site-tagged competition experiments were performed to prove that the binding of MYR or MYT to PK could alter its micro-environment and conformation. Molecular docking results revealed that either MYR or MYT spontaneously interacted with PK at a single binding site via hydrogen bonding and hydrophobic interactions, which is consistent with the results of spectroscopic measurements. A 30 ns molecular dynamics simulation was conducted for both PK-MYR and PK-MYT complexes. The calculation results showed that no large structural distortions or interaction changes occurred during the entire simulation time span. The average RMSD changes of PK in PK-MYR and PK-MYT were 2.06 and 2.15 Å, respectively, indicating excellent stability of both complexes. The molecular simulation results suggested that both MYR and MYT could interact with PK spontaneously, which is in agreement with spectroscopic results. This agreement between experimental and theoretical results indicates that the method herein could be feasible and worthwhile for protein-ligand complex studies.

Campomanesia lineatifolia Ruiz & Pavón (Myrtaceae): Isolation of major and minor compounds of phenolic-rich extract by high-speed countercurrent chromatography and anti-inflammatory evaluation.

ETHNOPHARMACOLOGICAL RELEVANCE: Campomanesia lineatifolia Ruiz & Pavón (Myrtaceae), an edible species found in Brazilian Forest, possesses leaves that are traditionally used for the treatment of gastrointestinal disorders in Brazil. Extracts of C. lineatifolia are rich in phenolics and exhibit antioxidant, and gastric antiulcer properties. Furthermore, Campomanesia spp. have been described to possess anti-inflammatory properties, but studies related to chemical constituents of C. lineatifolia are scarce in the literature. AIM OF THE STUDY: This work aims to identify the chemical composition of the phenolic-rich ethanol extract (PEE) from C. lineatifolia leaves and evaluate the anti-inflammatory activity that could be related to its ethnopharmacological use. MATERIALS AND METHODS: The high-speed countercurrent chromatography (HSCCC), using an isocratic and a step gradient elution method, and NMR, HPLC-ESI-QTOF-MS/MS were used to isolate and identify the chemicals of PEE, respectively. Lipopolysaccharide-(LPS)-stimulated THP-1 cells were used to evaluate the anti-inflammatory activities from PEE and the two majority flavonoids isolated by measure TNF-α and NF-κB inhibition assays. RESULTS: Fourteen compounds were isolated from the PEE, further identified by NMR and HPLC-ESI-QTOF-MS/MS, twelve of them are new compounds, and two others are already known for the species. The PEE, quercitrin and myricitrin promoted a concentration-dependent inhibition of TNF-α, and PEE promoted an inhibition of NF-κB pathway. CONCLUSIONS: PEE from C. lineatifolia leaves demonstrated significant anti-inflammatory activity that may be related to the traditional use to treat gastrointestinal disorders.

Modulatory effect of myricitrin against chromosome instability and cytostasis induced by bleomycin and oxaliplatin in CHO-K1 cells.

Myricitrin (MYR), a flavonol consumed in the leaves and fruits of plants of the Myrtaceae family, presents anti-proliferative, anti-inflammatory, anti-diabetic, and antioxidant properties in humans. However, there are few studies regarding the cyto-genotoxicity and the chemopreventive potential of MYR. Using the in vitro Micronucleus test, the cytostasis, mutagenicity, and modulatory effect of MYR in CHO-K1 cells were assessed. The concentrations of 39 and 78 µg/mL (p < 0.001.) of MYR decrease the cytokinesis-block proliferation index (CBPI) in the short exposure treatment (4 h), while in the extended treatment (24 h), concentrations of 4.8, 9.7, 19.5, 39 and 78 µg/mL (p < 0.001.) decreased the CBPI. MYR associated with oxaliplatin decreased CBPI at all tested concentrations in the pre-(p < 0.001) and post-treatments (p < 0.001), but there was no decrease when associated with bleomycin. As for chromosome instability, MYR did not increase the frequency of micronuclei (MNi), nucleoplasmic bridges (NPBs), or nuclear buds (NBUDs) in the 4 h exposure time, however, in the 24 h treatment, MYR increased the frequency of MNi and NPBs at concentration 19.5 µg/mL (p < 0.001). As for the modulatory effect, MYR associated with bleomycin decreased the frequency of MNi, NPBs, and NBUDs at all concentrations in the pretreatment (MNi and NPBs p < 0.001, NBUDs p < 0.05) and simultaneously (MNi, NPBs and NBUDs p < 0.001). When associated with oxaliplatin, the simultaneous treatment decreased the frequency of MNi (p < 0.001) and NBUDs (p < 0.01) at all concentrations, however, in the post-treatment, MYR increased MNi (p < 0.001) and NPBs p < 0.05) in CHO-K1 cells, when compared to oxaliplatin alone. The results demonstrated that MYR could modulate the mutagenic and cytostatic actions of bleomycin and oxaliplatin, demonstrating distinct behaviors, depending on the mechanism of action of the chemotherapeutic agent.

Unveiling interaction mechanisms between myricitrin and human serum albumin: Insights from multi-spectroscopic, molecular docking and molecular dynamic simulation analyses.

Myricitrin is a natural polyhydroxy flavonoid and is mainly derived from the bark and leaves of the Chinese Bayberry tree (Myrica rubra). It has different pharmacological activities, including antioxidative, anti-inflammatory, hypoglycemic, antiviral, liver protection and cholagogue properties, and may be added to foods, pharmaceuticals, and cosmetic products for antioxidant purposes. In this study, the interaction mechanism between myricitrin and human serum albumin (HSA) was investigated using spectroscopic methods, molecular docking techniques, and molecular dynamic simulations. We showed that the HSA/myricitrin interaction exhibited a static fluorescence quenching mechanism, and that binding processes were spontaneous in nature, with the main forces exemplified by hydrogen bonding, hydrophobic interactions, and electrostatic interactions. Fluorescence spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, synchronous fluorescence spectroscopy, three-dimensional (3D) fluorescence spectroscopy, micro-Fourier transform infrared spectroscopy (micro-FTIR), and circular dichroism (CD) spectroscopy showed that myricitrin binding altered the HSA conformation to some extent. Competitive binding and molecular docking studies showed that the preferred binding of myricitrin on HSA was in the sub-structural domain IIA (Site I); molecular dynamic simulations revealed that myricitrin interacted with HSA to produce a well stabilized complex, and it also generated a conformational change in HSA. The antioxidant capacity of the HSA-myricitrin complex was reduced when compared with free myricitrin. The identification of HSA-myricitrin binding mechanisms provides valuable insights for the application of myricitrin to the food and pharmaceutical industries.