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Neuraminidase is an important target in the treatment of the influenza A virus. Screening natural neuraminidase inhibitors from medicinal plants is crucial for drug research. This study proposed a rapid strategy for identifying neuraminidase inhibitors from different crude extracts (Polygonum cuspidatum, Cortex Fraxini, and Herba Siegesbeckiae) using ultrafiltration combined with mass spectrometry guided by molecular docking. Firstly, the main component library of the three herbs was established, followed by molecular docking between the components and neuraminidase. Only the crude extracts with numbers of potential neuraminidase inhibitors identified by molecular docking were selected for ultrafiltration. This guided approach reduced experimental blindness and improved efficiency. The results of molecular docking indicated that the compounds in Polygonum cuspidatum demonstrated good binding affinity with neuraminidase. Subsequently, ultrafiltration-mass spectrometry was employed to screen for neuraminidase inhibitors in Polygonum cuspidatum. A total of five compounds were fished out, and they were identified as trans-polydatin, cis-polydatin, emodin-1-O-β-D-glucoside, emodin-8-O-β-D-glucoside, and emodin. The enzyme inhibitory assay showed that they all had neuraminidase inhibitory effects. In addition, the key residues of the interaction between neuraminidase and fished compounds were predicted. In all, this study could provide a strategy for the rapid screening of the potential enzyme inhibitors from medicinal herbs., (© 2023 Wiley-VCH GmbH.)

Epstein-Barr virus (EBV), a human herpesvirus, is several human lymphoid malignancies-associated. Our earlier study found the effect of Polygonum cuspidatum root on promoting EBV-positive apoptosis. Therefore, this study investigated the effects of the Polygonum cuspidatum ethyl acetate subfraction containing emodin on EBV gene expression and anti-EBV tumor cells. Resultantly, the the Polygonum cuspidatum ethyl acetate subfraction containing emodin (F3a) promoted Raji cell death (50% cytotoxic concentration, CC 50 : 12.08 µg/mL); the 12.5 µg/mL F3a effect transcribed BRLF1 and BNLF1 and increased latent membrane protein 1 (LMP1), which may reduce the intracellular phospho-extracellular signal-regulated kinase (ERK) and phospho-inhibitor of Nuclear factor kappa B α (IκBα). Meanwhile, the Raji cells increased the intracellular reactive-oxygen species (ROS), activated the apoptosis-related proteins, cleaved caspase 3 and poly(ADP-ribose)polymerase (PARP), and increased the apoptosis percentage. Therefore, the Polygonum cuspidatum ethyl acetate subfraction containing emodin could be a therapeutic drug for EBV-related tumors.

Solid phase extraction applied to plant matrices is nowadays a well validated technique allowing the concentration and purification of selected secondary metabolites for subsequent analysis. In this short communication we screened the efficiency of 16 selected solid supports including layered structures (hydrotalcites and zirconium phosphate), magnesium oxide and hydroxide, and finally the phyllosilicates talc and bentonite for the selective concentration of the anthraquinone emodin from raw solid extracts of Polygonum cuspidatum Siebold & Zucc. (sin. Reynoutria japonica Houtt.) (Polygonaceae), commonly known as " Japanese knotweed " . An ethanolic solution of sample extract from this plant was vigorously mixed with fixed quantities of each solid support. Subsequent HPLC analysis, coupled to photodiode array detection, revealed that, among the solid supports assayed, the hydrotalcite zinc aluminum oleate and magnesium oxide were largely the most effective to this concern. Both were able to extract emodin from the raw extract in percentages of 81.5 % and 92.4 %, respectively. The application of the title supports for the extraction and concentration in the solid phase of anthraquinones from raw plant extracts have been reported herein for the first time., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Many types of cancer cells show a characteristic increase in glycolysis, which is called the "Warburg effect." By screening plant extracts, we identified one that decreases cellular adenosine triphosphate (ATP) levels and suppresses proliferation of malignant melanoma B16F10 cells, but not of noncancerous MEF cells. We showed that its active ingredient is emodin, which showed strong antiproliferative effects on B16F10 cells both in vitro and in vivo. Moreover, we also found that emodin can function as a mitochondrial uncoupler. Consistently, three known mitochondrial uncouplers also displayed potent antiproliferative effects and preferential cellular ATP reduction in B16F10 cells, but not in MEF cells. These uncouplers provoked comparable mitochondrial uncoupling in both cell types, but they manifested dramatically different cellular effects. Namely in MEF cells, these uncouplers induced three to fivefold increases in glycolysis from the basal state, and this compensatory activation appeared to be responsible for the maintenance of cellular ATP levels. In contrast, B16F10 cells treated with the uncouplers showed less than a twofold enhancement of glycolysis, which was not sufficient to compensate for the decrease of ATP production. Together, these results raise the possibility that uncouplers could be effective therapeutic agents specifically for cancer cells with prominent "Warburg effect.", (© 2019 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.)

The present study aimed to investigate the anti‑arthritic effect of physcion 8‑O‑β‑glucopyranoside (POGD) and its possible mechanisms. The anti‑proliferative effects of POGD on MH7A cells were detected using a CCK‑8 assay, and the release of pro‑inflammatory cytokines, interleukin (IL)‑1β, IL‑6, IL‑8, IL‑12 and IL‑17A, were determined by ELISA. A type II collagen‑induced arthritis (CIA) rat model was established to evaluate the anti‑arthritic effect of POGD in vivo. The paw volumes, arthritis indices and serum levels of tumor necrosis factor (TNF)‑α, IL‑1β, IL‑6, IL‑8, IL‑17A were determined by ELISA. The mRNA expression levels of matrix metalloproteinase (MMP)‑2, MMP‑3, MMP‑9, vascular endothelial growth factor and cyclooxygenase‑2 were determined by reverse transcription‑quantitative polymerase chain reaction analysis, and the expression levels of transforming growth factor (TGF)‑β1, small mothers against decapentaplegic (Smad)4, Smad7, c‑Jun N‑terminal kinase (JNK), phosphorylated (p‑)JNK, p‑P38, P38, p‑extracellular signal‑regulated kinase (ERK)1/2, ERK1/2, nuclear factor (NF)‑κB p65 in the nucleus (N), cytosolic NF‑κB p65 (C), and inhibitor of NF‑κB (IκB) were determined by western blot analysis. The results indicated that POGD significantly inhibited MH7A cell growth. POGD markedly inhibited paw swelling and the arthritis indices of the CIA rats, and POGD may also inhibit the release of pro‑inflammatory cytokines. Furthermore, POGD downregulated the expression levels of TGF‑β1, Smad4, NF‑κB p65 (N), p38, p‑p38, p‑ERK1/2, JNK, p‑JNK, TGF‑β1, Smad4, p‑JNK, JNK, p‑P38, P38, p‑ERK1/2, ERK1/2 and NF‑κB p65 (N), and upregulated the Smad7, NF‑κB p65 (C) and IκB in TNF‑α induced MH7A cells. In conclusion, the results suggested that POGD is a promising potential anti‑inflammatory drug, and that POGD may decrease the expression of pro‑inflammatory cytokines and mediators via inhibiting the TGF‑β/NF‑κB/mitogen‑activated protein kinase pathways.

Ichthyophthirius multifiliis is a ciliated parasite that infests almost all freshwater fish species and causes great economic losses to the aquaculture industry. In this study, a compound with anti-I. multifiliis activity was isolated from Polygonum cuspidatum and identified as emodin. In vitro anti-I. multifiliis results showed that emodin at 1 mg/L killed all I. multifiliis theronts for 96.0 min, and at 0.5 mg/L or lower concentrations could not kill all I. multifiliis theronts, but could significantly reduce the infectivity of theronts after pretreatment with emodin at the low concentrations mentioned above for 2 h. Additionally, emodin at 1 mg/L and 2 mg/L completely terminated the reproduction of nonencysted and encysted tomonts, respectively. In vivo tests, emodin at 0.5 mg/L could cure infected grass carp and protect naive fish from I. multifiliis infection by continuous adding emodin for 10 days. The 96 h median lethal concentration (LC 50 ) of emodin to grass carp was 3.15 mg/L, which were approximately 18 and 7 times the median effective concentration (EC 50 ) of emodin for killing theronts (0.18 mg/L) and nonencysted tomonts (0.45 mg/L), respectively. On the basis of these results, emodin is an effective compound for the development of a new drug against I. multifiliis., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Haemophilus parasuis is the causative agent of Glässer's disease, which leads to serious economic loss to the swine industry. Although antibiotics are widely used to control infections, outbreaks of this disease repeatedly happen. In this study, emodin from Polygonum cuspidatum showed potent inhibitory effect against H. parasuis. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of emodin were 32 and 64μg/mL, respectively. The antibacterial kinetic curves indicated the antibacterial activity of emodin was in a concentration-dependent manner. Cell membrane permeability and flow cytometry assays proved that emodin could destroy cell membrane integrity and increase membrane permeability, and fluorescence spectra assay indicated emodin has influenced conformation of membrane protein. Under transmission electron microscopy, serious lesions of H. parasuis exposed to emodin (64μg/mL) were found, including irregular cell shape, plasmolysis, ruptured cell wall and membrane and cytoplasmic vacuolation. These results suggested that emodin could be used as candidate for treating Glässer's disease., (Copyright © 2016 Elsevier GmbH. All rights reserved.)

Podocyte injury contributes to renal damage and, eventually, to the occurrence of proteinuria in diabetic nephropathy. The aim of the present study was to investigate the effect of an ethanol extract from Rhizoma Polygonum cuspidatum (P. cuspidatum) on proteinuria and podocyte injury, and elucidate the underlying mechanism for streptozotocin (STZ)‑induced diabetic nephropathy. The protective effects of P. cuspidatum extract (PCE) on renal podocytes in STZ‑induced diabetic rats were also investigated. PCE (100 or 350 mg/kg/day) was administered to STZ‑induced diabetic rats for 16 weeks, and blood glucose levels, body weight and proteinuria were measured. A double labeling technique with the terminal deoxynucleotidyl transferase dUTP nick end labeling assay was performed and synaptopodin expression was observed. In addition, cleaved caspase‑3, methylglyoxal (MGO) and 8‑hydroxydeoxyguanosine (8‑OHdG) expression levels were measured. STZ‑induced diabetic rats developed hyperglycemia and proteinuria. Increased apoptosis of the podocytes and increased cleaved caspase‑3, MGO and 8‑OHdG expression levels, as well as decreased synaptopodin expression were detected in the glomeruli of STZ‑induced diabetic rats. However, treatment with PCE for 16 weeks restored protein levels to normal, and reduced podocyte loss and apoptosis. Levels of caspase‑3 and MGO expression, as well as oxidative stress were ameliorated by PCE treatment. In addition, emodin, a biologically active ingredient of PCE, exerted an MGO scavenging effect and inhibited MGO‑derived advanced glycation end‑product formation. These findings indicate that PCE may be administered to prevent proteinuria and podocyte loss in STZ‑induced diabetic rats partly by inhibiting podocyte apoptosis and cleaved caspase‑3 expression, and by restoring the balance of oxidative stress and MGO expression.

Polygonum cuspidatum is widely used as a medicinal herb in Asia. In this study, we examined the ethyl acetate subfraction F3 obtained from P. cuspidatum root and its major component, emodin, for their capacity to inhibit the Epstein-Barr virus (EBV) lytic cycle. The cell viability was determined by the MTT [3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyltetrazolium bromide] method. The expression of EBV lytic proteins was analyzed by immunoblot, indirect immunofluorescence and flow cytometric assays. Real-time quantitative PCR was used to assess the EBV DNA replication and the transcription of lytic genes, including BRLF1 and BZLF1. Results showed that the F3 and its major component emodin inhibit the transcription of EBV immediate early genes, the expression of EBV lytic proteins, including Rta, Zta, and EA-D and reduces EBV DNA replication, showing that F3 and emodin are potentially useful as an anti-EBV drug.

The lack of effective therapeutics for Coxsackievirus B₄ (CVB₄) infection underscores the importance of finding novel antiviral compounds. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is one of the natural anthraquinone derivatives obtained from the root and rhizome of Polygonum cuspidatum. In the present study, the possibility of using emodin as a potential antiviral to treat CVB₄ infection was explored in vitro and in mice. Emodin reduced CVB₄ entry and replication on Hep-2 cells in a concentration- and time-dependent manner, with a 50% effective concentration (EC₅₀) of 12.06 μM and selectivity index (SI) of 5.08, respectively. The inhibitory effect of emodin for CVB₄ entry and replication was further confirmed by a quantitative real time PCR (qPCR) assay. The results further showed that the mice orally treated with different dosages of emodin displayed a dose dependent increase of survival rate, body weight and prolonged mean time of death (MTD), accompanied by significantly decreased myocardial virus titers and pathologic scores/lesions. Moreover, emodin could inhibit CVB₄-induced apoptosis in vitro and in vivo. Our results indicated that emodin could be used as potential antiviral in the post-exposure prophylaxis for CVB₄ infection.

Citreorosein was isolated from P. cuspidatum as a new oestrogenic compound, together with emodin and its glucoside, by silica gel column chromatography and preparative high-performance liquid chromatography sequentially. Oestrogenic activity was determined by a recombinant yeast assay.

Microwave-assisted, aqueous two-phase extraction was investigated to obtain effective constituents, including piceid, resveratrol and emodin in Polygonum cuspidatum. An aqueous two-phase system consisting of 25% (w/w) ethanol 21% (w/w) (NH(4))(2)SO(4) gave equal yields of piceid, and 1.1- and 1.9-times higher yields of resveratrol and emodin, respectively, than that achieved by microwave-assisted extraction and heat reflux extraction. Three-separate operations, extraction, clarification and concentration, are hereby integrated into a single step to get higher yields at lower cost. This is therefore a potentially useful method for the extraction and purification of target products.

Vibrio vulnificus, a good model organism of bacterial septicemia, causes fatal septicemia manifesting a fulminating course and a high mortality rate within days. In order to identify new natural substances preventing V. vulnificus infection, a plant library was screened for inhibiting cytotoxicity to host cells by using Trypan blue staining and LDH assay. We found that Polygoni Cuspidati Radix potently suppressed the acute death of HeLa and RAW264.7 cells in a dose dependent manner. Further studies revealed that Polygoni Cuspidati Radix inhibited V. vulnificus growth and survival in HI broth and seawater, respectively. We confirmed that Polygoni Cuspidati Radix contained high level of emodin by thin layer chromatography (TLC). Emodin showed direct antibacterial activity against V. vulnificus. In addition, emodin prevented the morphologic damages and acute death of HeLa cells caused from V. vulnificus. The safety of Polygoni Cuspidati Radix and emodin to host cells was confirmed by MTT assay. Polygoni Cuspidati Radix and emodin protected mice from V. vulnificus infection.

High-performance liquid chromatographic separation is performed to extract active components from the traditional Chinese medicine Polygonum cuspidatum using a trans-resveratrol imprinted polymer. Good separation and purification of trans-resveratrol and emodin from the Polygonum cuspidatum extract are achieved after condition optimization. The extraction recoveries are 83% and 99% for trans-resveratol and emodin, respectively. The results show that the molecularly imprinted polymer can be used as a selective extraction material for the extraction and purification of trans-resveratrol and emodin from Polygonum cuspidatum.

Emodin and physcion are abundant anthraquinone compounds found in the traditional Chinese medicinal herb Polygonum cuspidatum Sied. et Zucc. In this paper, emodin and physcion were successfully extracted with supercritical CO2 plus ethanol modifier after the extraction conditions were optimized with uniform design-sequential optimization. Results showed that the ethanol modifier concentration was the main factor for the effective extraction of the emodin. The optimal extraction condition was obtained: 20 MPa, 30 degrees C, and 95% ethanol, at which the yields of emodin and physcion were 0.616 and 0.178 g/100 g, respectively. The yield obtained by supercritical fluid extraction (SFE) was a little lower than that obtained by sonication extraction (SE). The crude extract obtained by SFE was further isolated and purified by semipreparative chromatography with the mobile phase composed of methanol-water (90:1, v/v). Emodin and physcion were obtained with purity 98.6 and 99.1%, respectively, when determined by HPLC, and identification was performed by retention time and UV spectra of the standards. The result suggested that SFE is an alternative and promising method for extraction of the two compounds from P. cuspidatum owing to its environment-friendly properties and fewer coextracts.

Objective: To establish a HPLC method for simultaneous determination of resveratrol, emodin, chrysophanol, physcion in root of Polygonum cuspidatum and its extract., Method: The separation was performed in a Hypersil ODS C18 column with a mobile phase of Acetonitrile-1%HAc. The flow rate was 1.0 mL x min(-1) and detection wavelength was at 287 nm., Result: The mean recovery and RSD of resveratrol, emodin, chrysophanol, physcion was 101.8%, RSD 1.7%; 96.2%, RSD 1.4%; 99.7%, RSD 1.0%; 98.60%, RSD 0.97% respectively., Conclusion: The method is accurate, simple and reliable. It can be used for quality control of P. cuspidatum and its extract.