Flavonoid Myricetin as Potent Anticancer Agent: A Possibility towards Development of Potential Anticancer Nutraceuticals / 中国结合医学杂志

Good nutrition plays a crucial role in maintaining a balanced lifestyle. The beneficial effects of nutrition have been found to counteract nutritional disturbances with the expanded use of nutraceuticals to treat and manage cardiovascular diseases, cancer, and other developmental defects over the last decade. Flavonoids are found abundantly in plant-derived foods such as fruits, vegetables, tea, cocoa, and wine. Fruits and vegetables contain phytochemicals like flavonoids, phenolics, alkaloids, saponins, and terpenoids. Flavonoids can act as anti-inflammatory, anti-allergic, anti-microbial (antibacterial, antifungal, and antiviral) antioxidant, anti-cancer, and anti-diarrheal agents. Flavonoids are also reported to upregulate apoptotic activity in several cancers such as hepatic, pancreatic, breast, esophageal, and colon. Myricetin is a flavonol which is naturally present in fruits and vegetables and has shown possible nutraceutical value. Myricetin has been portrayed as a potent nutraceutical that may protect against cancer. The focus of the present review is to present an updated account of studies demonstrating the anticancer potential of myricetin and the molecular mechanisms involved therein. A better understanding of the molecular mechanism(s) underlying its anticancer activity would eventually help in its development as a novel anticancer nutraceutical having minimal side effects.

Myricetin attenuates renal fibrosis by activating Nrf2/HO-1 pathway to inhibit oxidative stress / 药学学报

This paper investigates the effect of myricetin (MYR) on renal fibrosis induced by unilateral ureteral obstruction (UUO) and common bile duct ligation (CBDL) in mice and its mechanism. The animal experiment has been approved by the Ethics Committee of China Pharmaceutical University (NO: 2022-10-020). Thirty-five ICR mice were divided into control, UUO, UUO+MYR, CBDL and CBDL+MYR groups. H&E and Masson staining were used to detect pathological changes in kidney tissues. Western blot (WB) was used to detect the expression of fibrosis-related proteins in renal tissue, and total superoxide dismutase (SOD) activity detection kit (WST-8) was used to detect the changes of total SOD in renal tissue of CBDL mice. In vitro, HK-2 cells and transforming growth factor beta 1 (TGF-β1, 10 ng·mL-1) were used to induce fibrotic model, and high glucose (30 mmol·L-1) was used to induce oxidative stress model, and then treated with different concentrations of MYR, WB was used to detect the expression of fibrosis and oxidative stress-related proteins, while NIH/3T3 cells were treated with different concentrations of MYR, and their effects on cell proliferation were detected by 5-bromo-2′-deoxyuridine (Brdu). The results showed that the renal lesions in UUO group and CBDL group were severe, collagen deposition was obvious, the expression of collagen-Ⅰ (COL-Ⅰ), α-smooth muscle actin (α-SMA), fibronectin (FN), vimentin and plasminogen activator inhibitor-1 (PAI-1) protein was up-regulated, and the activity of SOD enzyme in CBDL group was significantly decreased. MYR partly reversed the above changes after treatment. MYR inhibited the proliferation of NIH/3T3 cells but had no effect on the proliferation of HK-2 cells, and decreased the upregulation of PAI-1, FN and vimentin in HK-2 cells stimulated by TGF-β1. MYR can also up-regulate the down-regulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in HK-2 cells stimulated by high glucose. To sum up, MYR can improve renal fibrosis in vivo and in vitro, probably by inhibiting the proliferation of fibroblasts and activating Nrf2/HO-1 signal pathway to inhibit oxidative stress.

In vivo Gonadoprotective Effects of Myricetin on Cisplatin- Induced Testicular Damage via Suppression of TLR4/NF-kB Inflammation Pathway and Heat-Shock Response / Efectos Gonadoprotectores in vivo de la Miricetina sobre el Daño Testicular Inducido por Cisplatino Mediante la Supresión de la Vía de Inflamación TLR4/NF-kB y la Respuesta al Choque Térmico

SUMMARY: The aim of this study is to reveal the gonadoprotective effects of myricetin (MYC), which has many biological properties, on cisplatin (CP)-induced testicular damage in rats. For this purpose, 40 male Wistar albino rats were divided into 4 groups as Control (group given no treatment), MYC (group given 5 mg/kg/i.p myricetin for 7 days), CP (group given 7 mg/kg/i.p cisplatin at 7th day) and MYC + CP (group given 5 mg/kg/i.p myricetin for 7 days before 7 mg/kg/i.p cisplatin injection). After administrations, testicular tissues of animals were extracted and processed according to tissue processing protocol. Hematoxylin & Eosin staining were performed to evaluate the histopathological changes and Johnsen'sTesticular Biopsy Score (JTBS) was applied and mean seminiferous tubule diameters (MSTD) were measured to compare experimental groups in terms of histopathological changes. Moreover, TLR4, NF-kB, HSP70 and HSP90 expression levels were detected by immunohistochemical staining and the density of immunoreactivity were measured to determine the difference in the expression levels of these factors among groups. Additionally, testicular apoptosis was detected via TUNEL assay. JTBS and MSTD data were significantly lower in CP group compared to other groups and MYC administrations significantly protects testicular tissue against CP-induced damage. Moreover, TLR4, NF-kB, HSP70 and HSP90 expressions and apoptotic cells significantly increased in the CP group (p<0.05). However, MYC administrations exerted a strong gonadoprotective effect on testicular tissue in terms of these parameters in MYC+CP group (p<0.05). According to our results, we suggested that MYC can be considered as a protective agent against cisplatin-induced testicular damage.

El objetivo de este estudio es revelar los efectos gonadoprotectores de la miricetina (MYC), que tiene muchas propiedades biológicas, sobre el daño testicular inducido por cisplatino (CP) en ratas. Para este propósito, se dividieron 40 ratas albinas Wistar macho en 4 grupos: Control (grupo que no recibió tratamiento), MYC (grupo que recibió 5 mg/kg/i.p de miricetina durante 7 días), CP (grupo que recibió 7 mg/kg/i.p de cisplatino al séptimo día) y MYC + CP (grupo que recibió 5 mg/ kg/i.p de miricetina durante 7 días antes de la inyección de 7 mg/ kg/i.p de cisplatino). Después de las administraciones, se extrajeron y procesaron tejidos testiculares de animales según el protocolo de procesamiento de tejidos. Se realizó tinción con hematoxilina y eosina para evaluar los cambios histopatológicos y se aplicó la puntuación de biopsia testicular de Johnsen (JTBS) y se midieron los diámetros medios de los túbulos seminíferos (MSTD) para comparar los grupos experimentales en términos de cambios histopatológicos. Además, los niveles de expresión de TLR4, NF-kB, HSP70 y HSP90 se detectaron mediante tinción inmunohistoquímica y se midió la densidad de inmunorreactividad para determinar la diferencia en los niveles de expresión de estos factores entre los grupos. Además, se detectó apoptosis testicular mediante el ensayo TUNEL. Los datos de JTBS y MSTD fueron significativamente más bajos en el grupo CP en comparación con otros grupos y las administraciones de MYC protegen significativamente el tejido testicular contra el daño inducido por CP. Además, las expresiones de TLR4, NF-kB, HSP70 y HSP90 y las células apoptóticas aumentaron significativamente en el grupo CP (p<0,05). Sin embargo, las administraciones de MYC ejercieron un fuerte efecto gonadoprotector sobre el tejido testicular en términos de estos parámetros en el grupo MYC+CP (p<0,05). Según nuestros resultados, sugerimos que MYC puede considerarse como un agente protector contra el daño testicular inducido por cisplatino.

Myricetin inhibits interferon-γ-induced programmed death ligand-1 and indoleamine 2, 3-dioxygenase 1 expression in lung cancer cells / 中国药理学与毒理学杂志

OBJECTIVE Programmed death ligand-1 (PD-L1) and indoleamine 2, 3-dioxygenase 1 (IDO1) are immune checkpoints which can be induced by interferon-γ(IFN-γ) in the tumor microenvironment, leading to immune escape of tumors. Myricetin (MY) is a flavonoid distributed in many edible and medicinal plants. The aim of this study is to clarify the effect and the mechanism of MY on inhibiting IFN-γ-induced PD-L1 and IDO1 in lung cancer cells. METHODS Expressions of PD-L1 and major histocompatibility complex-I (MHC-I) were evaluated by flow cytometry and Western blotting, and the expression of IDO1 was measured by Western blotting. qRT-PCR was used to detect their mRNA levels. The function of T cells was evaluated using a co-culture system consist of lung cancer cells and the Jurkat-PD-1 T cell line that overexpressing PD-1. Molecular docking analysis, Western blotting and immunofluorescence were used for mechanism study. RESULTS MY potently inhibited IFN-γ-induced PD-L1 and IDO1 expression in human lung cancer cells, while didn't show obvious effect on the expression of MHC-I. In addition, MY restored the survival, proliferation, CD69 expression and interleukin-2 (IL-2) secretion of Jurkat-PD-1 T cells suppressed by IFN-γ-treated lung cancer cells in the co-culture system. Mechanistically, IFN-γ up-regulated PD-L1 and IDO1 at the transcriptional level through the JAK-STAT-IRF1 axis, which was targeted and inhibited by MY. CONCLUSION Our research revealed a new insight into the anti-tumor effects of MY which inhibited IFN-γ-induced PD-L1 and IDO1 expression, supporting the potential of MY in anti-tumor immunotherapy.

Recent advances in research on vine tea,a potential and functional herbal tea with dihydromyricetin and myricetin as major bioactive compounds / 药物分析学报

Vine tea has been used as an herbal tea by several ethnic minorities for hundreds of years in China.Flavonoids,a kind of indispensable component in a variety of nutraceutical,pharmaceutical and cosmetic applications,are identified to be the major metabolites and bioactive ingredients in vine tea.Interest-ingly,vine tea exhibits a wide range of significant bioactivities including anti-oxidant,anti-inflammatory,anti-tumor,antidiabetic,neuroprotective and other activities,but no toxicity.These bioactivities,to some extent,enrich the understanding about the role of vine tea in disease prevention and therapy.The health benefits of vine tea,particularly dihydromyricetin and myricetin,are widely investigated.However,there is currently no comprehensive review available on vine tea.Therefore,this report summarizes the most recent studies investigating bioactive constituents,pharmacological effects and possible mechanisms of vine tea,which will provide a better understanding about the health benefits and preclinical assessment of novel application of vine tea.

Enzymatic synthesis of myricetin 3-O-galactoside through a whole-cell biocatalyst / 中草药·英文版

Objective: Myricetin 3-O-galactoside is an active compound with pharmaceutical potential. The insufficient supply of this compound becomes a bottleneck in the druggability study of myricetin 3-O-galactoside. Thus, it is necessary to develop a biosynthetic process for myricetin 3-O-galactoside through metabolic engineering. Methods: Two genes OcSUS1 and OcUGE1 encoding sucrose synthase and UDP-glucose 4-epimerase were introduced into BL21(DE3) to reconstruct a UDP-D-galactose (UDP-Gal) biosynthetic pathway in Escherichia coli. The resultant chassis strain was able to produce UDP-Gal. Subsequently, a flavonol 3-O-galactosyltransferase DkFGT gene was transformed into the chassis strain producing UDP-Gal. An artificial pathway for myricetin 3-O-galactoside biosynthesis was thus constructed in E. coli. Results: The obtained engineered strain was demonstrated to be capable of producing myricetin 3-O-galactoside, reaching 29.7 mg/L. Conclusion: Biosynthesis of myricetin 3-O-galactoside through engineered E. coli could be achieved. This result lays the foundation for the large-scale preparation of myricetin 3-O-galactoside.

Effect of myricetinon enterovirus 71 infection in vitro / 中国药理学通报

Aim To investigate the antiviral activity and mechanism of myricetin against enterovirus 71 (E V 7 1) infection. Methods The cytopathic effect (CPE) and plaque assay were used to observe the antiviral effect of myricetin against EV71 in Vero cell. The cells were treated with myricetin at different concentrations combined with crystal violet staining to detectthe cytotoxicity of myricetin. The effect of myricetin on VP1 protein expression was detected by Western blot. The effect of myricetin on VP1 gene expressionwas evaluated byRT-PCR. Results Myricetin pretreatment at 2. 5-20 fimol L-1' significantly inhibitedcell death induced by EV71 infection in a dose-dependent manner with the IC50 value of 5. 6 jxmol • L-1. Compared to virus control group, myricetin could significantly reduce the viral titer at the concentration of 2. 5 ~ 20 u,mol • L-1. The results of Western blot and RT-PCR showed that myricetin could markedlyreduce the gene and protein expression levels of viral capsid protein VP1. Conclusion Myricetin has significant antiEV71 activity in vitro.

Pharmacological activities of myricetin and its glycosides / 中国中药杂志

Myricetin and its glycosides are important flavonols commonly found in plants, and they are natural organic compounds with diverse pharmacological activities. Numerous studies have demonstrated that myricetin and its glycosides are strong antioxidants that have great potential in preventing, alleviating and assisting the treatment of chronic non-infectious diseases such as cancer, diabetes, and cardiovascular diseases. In addition, myricetin and its glycosides also have antiviral, antibacterial, anti-inflammatory, analgesic, liver protection and other pharmacological activities. Myricetin contains more hydroxyl groups in the parent ring structure than other flavonoids, so myricetin and its glycosides have stronger pharmacological activities than other flavonols or flavonoids such as quercetin and kaempferol. Therefore, myricetin and its glycosides have great development and application prospects. In this paper, the classification and distribution of myricetin and its glycosides, their pharmacological activity and mechanism, as well as comparison with other flavonoids were reviewed. In addition, limitations of the current research and application of myricetin and its glycosides were analyzed, and the further studies on pharmacological activities as well as their dose-activity relationship, structure-activity relationship, chemical modification, biosynthesis and application prospects of myricetin and its glycosides were discussed and proposed.

Myricetin ameliorates cytokine-induced migration and invasion of cholangiocarcinoma cells via suppression of STAT3 pathway

Aim of Study: Cholangiocarcinoma (CCA) is an aggressive cancer with considerable metastatic potential. Various cytokines secreted by tumor cells or cells in the tumor environment can promote the metastasis of CCA. The aim of the present study was to investigate the effect of myricetin on the inhibition of cytokine-induced migration and invasion and the associated cellular mechanisms in human CCA cells. Materials and Methods: CCA KKU-100 cells were treated with a pro-inflammatory cytokine mixture consisting of interleukin-6, interferon-γ, and tumor necrosis factor-α. The migratory and invasive ability of KKU-100 cells were determined using a wound-healing assay and transwell invasion assay. The effect of myricetin on cytokine-induced STAT3 activation in CCA cells was determined using Western blot analysis. The real-time polymerase chain reaction was performed to determine messenger RNA expression. Results: Myricetin significantly inhibited cytokine-induced migration and invasion of KKU-100 cells. Detailed molecular analyses revealed that myricetin suppressed the activation of the STAT3 pathway, evidently by a decrease of the active phospho-STAT3 protein expression after myricetin treatment. The cytokine-mediated upregulation of metastasis- and inflammatory-associated genes, which are downstream genes of STAT3 including the intercellular adhesion molecule-1, matrix metalloproteinase-9, inducible nitric oxide synthase, and cyclo-oxygenase 2 (COX-2), were also significantly abolished by myricetin treatment. Moreover, the anti-migratory and anti-invasive activities of a widely prescribed COX inhibitor, indomethacin, were also revealed. Conclusion: This finding reveals the anti-metastatic effect of myricetin against CCA cells which is mediated partly through suppression of the STAT3 pathway. This compound could be potentially useful as a therapeutic agent against CCA

The protective effects and mechanisms of myricetin on LPS-induced acute lung injury of BALB/c mice / 国际中医中药杂志

Objective To investigate whether myricetin (Myr) exert protective effects on acute lung injury induced by LPS and to explore its underlying mechanisms. Methods A total of 72 mice were divided into the control group, model group, myricetin group and active group, 18 in each group. Male BALB/c mice of the myricetin were given an intragastric injection of Myr (50 mg/kg), and the active group dexamethasone (Dex, 5 mg/kg) 1 h before intranasal instillation of LPS. While the other groups were given the same volum saline. 24 hours after LPS exposure, mice were sacrificed and various samples were collected for further analysis. Both levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the bronchoalveolar lavage fluid (BALF) were measured by ELISA kits. The numbers of total cells, macrophages, and neutrophils in the BALF were also determined using differential leukocyte cell count method. The phosphorylations of nuclear factor-kappa B (NF-κB) and IκB were further detected by western blot analysis. Results Compared with the model group, the levels of macrophages and neutrophils in BALF in the myricetin and active groups significantly decreased (P<0.01), while the total protein and W/D ratio of the lung tissue significantly decreased (P<0.05). Compared with the model group, the levels of TNF-α (5.47 ± 2.54 pg/ml, 4.19 ± 0.50 pg/ml vs. 15.28 ± 1.27 pg/ml), IL-1β(336.20 ± 41.06 pg/ml, 247.99 ± 25.12 pg/ml vs. 464.88 ± 34.51pg/ml), the MPO (0.74 ± 0.12 U/g, 0.61 ± 0.08 U/g vs. 1.66 ± 0.07U/g) in the myricetin and active groups significantly decreased (P<0.01). Compared with the model group, the expression of p-IκB/IκB (0.61 ± 0.01, 0.59 ± 0.01 vs. 0.95 ± 0.01), p-NF-κB/NF-κB (0.54 ± 0.01, 0.59 ± 0.03 vs. 0.96 ± 0.02) of the lung tissue in the myricetin and active groups significantly decreased (P<0.01). Conclusions Collectively, these findings revealed that Myr may alleviate the LPS-induced acute lung injury via relief of inflammatory reactions associated with blockage of the NF-κB signaling pathway.

Myricetin Protects Against High Glucose-Induced β-Cell Apoptosis by Attenuating Endoplasmic Reticulum Stress via Inactivation of Cyclin-Dependent Kinase 5

BACKGROUND: Chronic hyperglycemia has deleterious effects on pancreatic β-cell function and turnover. Recent studies support the view that cyclin-dependent kinase 5 (CDK5) plays a role in β-cell failure under hyperglycemic conditions. However, little is known about how CDK5 impair β-cell function. Myricetin, a natural flavonoid, has therapeutic potential for the treatment of type 2 diabetes mellitus. In this study, we examined the effect of myricetin on high glucose (HG)-induced β-cell apoptosis and explored the relationship between myricetin and CDK5. METHODS: To address this question, we subjected INS-1 cells and isolated rat islets to HG conditions (30 mM) in the presence or absence of myricetin. Docking studies were conducted to validate the interaction between myricetin and CDK5. Gene expression and protein levels of endoplasmic reticulum (ER) stress markers were measured by real-time reverse transcription polymerase chain reaction and Western blot analysis. RESULTS: Activation of CDK5 in response to HG coupled with the induction of ER stress via the down regulation of sarcoendoplasmic reticulum calcium ATPase 2b (SERCA2b) gene expression and reduced the nuclear accumulation of pancreatic duodenal homeobox 1 (PDX1) leads to β-cell apoptosis. Docking study predicts that myricetin inhibit CDK5 activation by direct binding in the ATP-binding pocket. Myricetin counteracted the decrease in the levels of PDX1 and SERCA2b by HG. Moreover, myricetin attenuated HG-induced apoptosis in INS-1 cells and rat islets and reduce the mitochondrial dysfunction by decreasing reactive oxygen species production and mitochondrial membrane potential (Δψm) loss. CONCLUSION: Myricetin protects the β-cells against HG-induced apoptosis by inhibiting ER stress, possibly through inactivation of CDK5 and consequent upregulation of PDX1 and SERCA2b.

Research progress on anti-infective, anti-inflammatory, and anti-oxidant activities of myricetin / 中草药

Myricetin is a kind of flavonoids widely existing in Myrica rubra and many other plants. Myricetin has lots of biological functions, such as antitumor, reducing blood sugar and lipid, protecting cardiovascular system, and reducing nervous injury. In recent years, people pay more attention to the antibacterial, antiviral, anti-inflammatory, anti-oxidant, and immunosuppressive activities of myricetin. This paper reviews the literatures on the pharmacological activities of myricetin in recent years at home and abroad and focuses on its effects and molecular mechanism of anti-infective, anti-inflammatory, immunoregulatory and anti-oxidation activities, in order to provide the evidences for developing new drugs.

Chemical constituents of Phyllanthus emblica and its anti-inflammation activities / 中草药

Objective: To study the chemical constituents and its anti-inflammtory activity effect of Phyllanthus emblica. Methods: The chemical constituents of P. emblica were isolated and purified by silica gel column chromatography, ODS column chromatography, Sephadex LH-20 column chromatography, semi-preparative high-performance liquid chromatography and recrystallization method. Through their spectra data, physical and chemical properties analysis, the structures of those compounds with high content were identified. LPS-induced RAW264.7 inflammatory cell model was established to evaluate the effect of compounds in P. emblica on proinflammatory factors (NO, IL-6, TNF-α, and MCP-1) of RAW264.7 inflammatory cells. Results: Totally, 14 compounds were isolated from P. emblica. and idetified as isovanillic acid (1), trans-cinnamic acid (2), p-hydroxybenzaldehyde (3), coniferyl aldehyde (4), quercetin (5), kaempferol-3-O-α-L-rhamnose (6), naringenin (7), 2-hydroxy-3-methyl phenylpropiolate (8), hydroquinone (9), myricetin (10), 2-furoic acid (11), methyl gallate (12), protocatechuic acid (13), gallic acid (14). The experiment of anti-inflammatroy effects showed that those compounds had different inhibitory effects on the production of inflammatory factors NO, IL-6, TNF-α and MCP-1. Conclusion: Compounds 1, 3, 4, 8-11 and 13 are isolated from P emblica for the first time. The anti-inflammatory effect of P. emblica is related to its phenolic acids.

Chemical constituents and pharmacological activities of Sedum aizoon form Guizhou province / 中草药

Objective: To study the chemical constituents of Sedum aizoon and to screen the anti-oxidant activities and α-glucosidase inhibitory activities of compounds. Methods: The compounds were separated and purified by various chromatographic techniques, and their structures were identified by physio-chemical properties and EI-MS, ESI-MS, 1H and 13C NMR. The anti-oxidant activity of compounds was screened by DPPH method. The obtained compounds were subjected to detection of α-glucosidase inhibitory activity by PNPG method. Results: Seventeen compounds were isolated from S. aizoon, which were identified as iriflophene (1), kaempferol (2), quercetin (3), myricetin (4), rhamnazin-3-O-β-D-glucopyranoside (5), isolariciresinol-9-O-β-D-glucopyranoside (6),myricitrime (7), myricetin-3-O-α-L-arabinopyranoside (8), iriflophenone-2-O-β-D-glucopyranoside (9), 2-O-(trans-caffeoyl)-malic acid 1-methyl-ester (10), 2-O-(trans-caffeoyl)-malic acid 1,4-dimethyl ester (11), 2-O-(trans-caffeoyl) malic acid (12), p-coumaric acid (13), ethyl gallate (14), butanedioic acid (15), 9(Z)-octadece-namide (16), and lotaustralin (17). Conclusion: Compounds 13 and 15 are isolated from S. aizoon for the first time. Compounds 9-12, and 16 are isolated from genus Sedum for the first time. Compounds 2, 3, 7, 8, 10, 12, and 14 had significant anti-oxidant activity. Compounds 8 showed moderate α-glucosidase inhibitory activity in vitro. Compound 3 showed strong α-glucosidase inhibitory activity in vitro.

Simultaneous Determination of 7 Anti-rheumatic Active Ingredients in Mongolian Medicine Sendeng- 4 Decoction Powder by HPLC-DAD / 中国药房

OBJECTIVE： To establish a method for simultaneous determination of 7 kinds of anti-rheumatic active ingredients in Mongolian medicine Sendeng-4 decoction powder， such as catechin， jasminoidin， dihydromyricetin， texifolin， rutin， myricetin and quercetin. METHODS： HPLC-DAD method was adopted. The determination was performed on Sil Green C18 column with mobile phase consisted of acetonitrile-0.1％ phosphoric acid solution （gradient elution） at the flow rate of 1 mL/min. The detection wavelength was set at 238 nm， and column temperature was 30 ℃. The sample size was 10 μL. RESULTS： The linear range of catechin， jasminoidin， dihydromyricetin， texifolin， rutin， myricetin and quercetin were 8.590-2 290， 10.56-3 901， 13.00-3 958， 8.815-564.2， 4.030-257.8， 8.130-750.5， 7.075-454.2 μg/mL （r≥0.999 1）， respectively； the limits of detection were 0.429 5，  0.264 0， 0.325 0， 0.220 4， 0.201 5， 0.203 2， 0.176 9 μg/mL， respectively； the limits of quantification were 1.030， 1.321， 1.302， 1.397， 1.637， 0.813 0， 0.707 5 μg/mL， respectively. RSDs of precision， stability （48 h） and repetition tests were all lower than 2.0％ （n＝6）. The average recoveries were 96.24％-99.28％ （RSD＝1.03％-1.63％， n＝6）. CONCLUSIONS： The established method is simple， accurate and reproducible， and can be used for simultaneous determination of catechin， jasminoidin， dihydromyricetin， texifolin， rutin， myricetin and quercetin in Mongolian medicine Sendeng-4 decoction powder.

Highly sensitive simultaneous electrochemical determination of myricetin and rutin via solid phase extraction on a ternary Pt@r-GO@MWCNTs nanocomposite / 药物分析学报

The simultaneous electrochemical determination of myricetin and rutin remains a challenge due to their indistinguishable potentials. To solve this problem, we constructed a ternary platinum nanoparticle, reduced graphene oxide, multi-walled carbon nanotubes (Pt@r-GO@MWCNTs) nanocomposite via a facile one-pot synthetic method. Under the optimized conditions, the ternary Pt@r-GO@MWCNTs nanocomposite exhibited good electrocatalytic activity toward myricetin and rutin via solid phase extraction and excellent performance for the simultaneous determination of myricetin and rutin. The oxidation peak current of myricetin was proportional to its concentrations in the range of 0.05-50μM with a detection limit of 0.01μM (S/N = 3). The linear range for rutin was 0.05-50μM with a detection limit of 0.005μM (S/N = 3). The ternary nanocomposite sensor also exhibited good reproducibility and stability, and was successfully used for the simultaneous determination of myricetin and rutin in real orange juice samples with recoveries ranging between 100.57％and 108.46％.

Lipoxygenase inhibitors flavonoids from Cyperus rotundus aerial parts

ABSTRACT Cyperus rotundus L. (Suada, Sueda, family: Cyperaceae) is vastly spread in several world's subtropical and tropical regions. It had variable traditional uses and bioactivities. A new flavonol derivative: cyperaflavoside (myricetin 3,3',5'-trimethyl ether 7-O-β-D-glucopyranoside) and five flavonoids: vitexin, orientin, cinaroside, quercetin 3-O-β-D-glucopyranoside, and myrcetin 3-O-β-D-glucopyranoside were separated from the methanolic extract of C. rotundus aerial parts. Their structures were verified based on UV, IR, NMR (1D and 2D), HRESIMS, and comparison with literature. All metabolites were assessed for their 5-lipoxygenase inhibitory potential. All compounds possessed 5-lipoxygenase inhibitory potentials with IC50s 5.1, 4.5, 5.9, 4.0, 3.7, and 2.3 µM, respectively, in comparison to indomethacin (IC50 0.98 µM). These results supported the traditional uses of C. rotundus in treating inflammation and its related symptoms.

Effects of myricetin on proliferation and apoptosis of glioma GL261 cells in mice / 吉林大学学报(医学版)

Objective: To observe the effects of myricetin on the proliferation, apoptosis, migration and invasion of mouse glioma GL261 cells, and to provide theoretical basis for myricetin in treating glioma. Methods: The mouse glioma GL261 cells were cultured in vitro. The experiment was divided into control group and different concentrations (10, 20, 30, 40, 50 and 60 μmol · L-1) of mytricetin groups. CCK-8 assay was used to detect the survival rates of the mouse glioma GL261 cells in various groups. The cell cycle of GL261 cells in various groups was detected by flow cytometry; Hoechst 33342 staining and flow cytometry were used to detect the apoptosis of G1261 cells in various groups. The number of migrated GL261 cells and the number of GL261 cells entering the lower chamber were detected by Trans well chamber assay. The expression levels of matrix metalloproteinases (MMPs) mRNA were detected by RT-PCR method. Results: The CCK-8 assay results showed that the survival rate of GL261 cells in 20 μmol · L-1 myricetin group was significantly decreased compared with control group (P< 0. 01). The flow cytometry results showed that the proportion of GL261 cells in Gi phase in 40 μmol · L-1 myricetin group was significantly increased (P<0. 05) and the proportion of GL261 cells in S phase was decreased (P<0. 05) compared with control group. The Hoechst 33342 staining results showed that the apoptotic bodies appeared in myricetin groups. The early and late apoptotic rates of GL261 cells in myricetin groups detected by AnnexinV/PI double staining were increased compared with control group (P<0. 05). Compared with control group, the number of migrated GL261 cells in 5, 10, and 20 μmol · L-1 myricetin groups was decreased in Traswell chamber assay (P<0. 05). Compared with control group, the number of GL261 cells entering the lower chamber in myricetin groups was decreased significantly (P<0. 05); the number of GL261 cells passing the Matrigel was gradully decreased with the increasing of the concentrations of myricetin. Compared with control group, the expression levels of MMP-2 and MMP-9 mRNA in the GL261 cells in 5 and 10 μmol · L-1 myricetin groups were decreased (P<0. 05). Conclusion: Myricetin could inhibit the proliferation of GL261 cells and induce the apoptosis. Meanwhile, it could also inhibit the migration and invasion of GL261 cells.

Induction effect of myricetin on apoptosis of human ovarian cancer SKOV3 cells by promoting DRP1-dependent mitochondrial fission / 吉林大学学报(医学版)

Objective: To observe the apoptosis and mitochondrial fission of human ovarian cancer SKOV3 cells after treated by myricetin and dynamin related protein 1 (DRP1) inhibitor mdivi-1 alone or combined, and to explore the mechanism of myricetin in inducing the apoptosis of SKOV3 cells. Methods: The SKOV3 cells were cultured in vitro and randomly divided into control group, mdivi-1 group, myricetin group and combined group. The cells in mdivi-1 group were treated with 50 μmol · L-1 madivi-1 for 1 h followed by common culture medium for 23 h; the cells in myricetin group were treated with 50 g · L-1 myricetin for 24 h; the cells combined group were treated with 50 jumol · L-1 midiv-1 for 1 h followed by 50 g · L-1 myricetin for 23 h. The survival rates of cells in various groups were detected by MTT assay. The apoptoic rates of cells in various groups were detected by Muse14 apoptosis detection kit. The expression levels of Cyt C, caspase3, DRP1 and FIS1 were observed by Western blotting method. The mitochondrial fission of cells in various groups was observed with MitoTracker® Red. Results; Compared with control group, the survival rate of cells in myricetin group was decreased significantly (P<0. 05); compared with myricetin group, the survival rate of cells in combined group was increased significantly (P<0. 05). Compared with control group, the apoptotic rate of cells in myricetin group was increased (P<0. 05); compared with myricetin group, the apoptotic rate of cells in combined group was decreased (P<0. 05). Compared with control group, the expression levels of Cyt C and caspase3 proteins in the cells in myricetin group were increased (P<0. 05); compared with myricetin group, the expression levels of Cyto C and caspase3 proteins in the cells in combined group were decreased (P<0. 05). Compared with control group, the degree of mitochondrial fission of the cells in myricetin group was increased; compared myricetin group, the degree of mitochondrial fission of the cells in combined group was decreased. Compared with control group, the expression levels of DRP1 and FIS1 proteins in the cells in myricetin group were increased (P<0. 05); compared with myricetin group, the expression levels of DRP1 and FIS1 proteins in the cells in combined group were decreased (P<0. 05). Conclusion: Myricetin can induce the apoptosis of human ovarian cancer SKOV3 cells by promoting the DRPl-dependent mitochondrial fission.

Myricetin blocks the activation,proliferation and secretion of cardiac fibroblasts induced by TGF-β / 医学研究生学报

Objective It is rarely reported whether myricetin inhibits the activation and function of cardiac fibroblasts and thereby prevents myocardial fibrosis. This study was to investigate the effects of myricetin on the activation,proliferation and secretion of cardiac fibroblasts and its possible molecular mechanisms. Methods Fibroblasts isolated from 1-3 days old rats were cultured and their activation,proliferation and secretion were induced with the transforming growth factor (TGF). The fibroblasts were incubated with myricetin at different concentrations of 1,3,10,30 and 100 μmol/L for 24 hours followed by detection of their proliferation with the CKK8 kit,the transcription levels of fibrotic factors by RT-PCR and the expression levels of α-SMA and signal proteins by immunoflu-orescence staining and Western blot,respectively. Results The expression of α-SMA was significantly up-regulated in the cardiac fi- broblasts of the rats in the TGF-β,30 μmol/L myricetin+TGF-β and 100 μmol/L myricetin+TGF-β groups as compared with that in the control group (P<0.05) but down-regulated in the 30 μmol/L myricetin+TGF-β and 100 μmol/L myricetin+TGF-β groups in com-parison with that in the TGF-β group (P<0.05). At 48 hours,the transcription levels of collagenⅠ,collagenⅢ,fibronectin and con-nective tissue growth factor were markedly higher in the TGF-β,30 μmol/L myricetin+TGF-β and 100 μmol/L myricetin+TGF-β groups than in the control group (P<0.05) but lower in the 30 μmol/L myricetin+TGF-β and 100 μmol/L myricetin+TGF-β groups than in the TGF-β group (P<0.05). The phosphorylation levels of smad2 and smad3 were remarkably elevated in the TGF-β,30 μmol/L myricetin+TGF-β and 100 μmol/L myricetin+TGF-β groups and the expression of smad4 reduced in the TGF-β group as com-pared with the control group (P<0.05). The levels of smad2,smad3 and smad4 were all significantly decreased in the 30 μmol/L myr-icetin+TGF-β and the 100 μmol/L myricetin+TGF-β groups in comparison with the TGF-β group (P<0.05). Conclusion Myricetin suppresses the activation,proliferation and secretion of cardiac fibroblasts induced by TGF-β via inhibiting the smad signaling pathway.