Review of selected animal models for respiratory coronavirus infection and its application in drug research.

Numerous viral pneumonia cases have been reported in Wuhan, Hubei in December 2019. The pathogen has been identified as a novel coronavirus, which was named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The biological characteristics and pathogenesis mechanism of SARS-CoV-2 are unclear and under progress. At present, no specific preventive and therapeutic drugs are available. Animal models can reproduce the viral replication cycle and the significant functions of respiratory coronavirus infection and are urgently needed to evaluate the efficacy of drugs and vaccines, the transmission route of respiratory coronavirus, clinical features, and so on. We reviewed the current animal models of respiratory coronavirus (SARS-CoV, MERS-CoV, and SARS-CoV-2) infection and made a comparative analysis of the route of inoculation, virus replication, clinical signs, histopathology, application, advantages, and disadvantages. Animal models of respiratory coronavirus include susceptible animal models, genetically modified models, and various animal models of infected virus adaptation strains, such as nonhuman primates, mice, hamsters, ferrets, New Zealand rabbits, cats, and other animal models, all of which have distinct advantages and limitations. This review will provide relevant information and important insights for disease management and control.

A synthetic biscoumarin suppresses lung cancer cell proliferation and induces cell apoptosis by increasing expression of RIP1.

Coumarin has a variety of biological activities and widely exists in plants. Biscoumarin, derived from coumarin, their synthetic methods and bioactivities of biscoumarins is the hotspot of the current research. In this study, we evaluated for the first time the anticancer of a synthetic biscoumarin (3,3'-(4-chlorophenyl)methylene)bis(4-hydroxy-2H-chromen-2-one, C3) on lung cancer cells and explored the related mechanism. C3 was simply prepared by 4-hydroxycoumarin and 4-chlorobenzaldehyde under ethanol. The structure of C3 was elucidated by various spectroscopic analyses. The antiproliferation effect of C3 was evaluated by the cell counting kit-8 assay. Cell cycle and apoptosis analysis were detected by flow cytometry. The expression of correlated proteins was determined using Western blotting. The result showed that C3 displayed a strong cytostatic effect on Lewis lung cancer (LLC) cells. C3 inhibited the proliferation of LLC cells, and induced G2/M phase cell cycle arrest. In addition, C3 possessed a significant reduction on cell apoptosis by increasing of RIP1 expression. Our data showed that C3 suppresses lung cancer cell proliferation and induces cell apoptosis, which is possibly involved with the RIP1.

Scopoletin and umbelliferone from Cortex Mori as protective agents in high glucose-induced mesangial cell as in vitro model of diabetic glomerulosclerosis.

Two known coumarins, scopoletin (SP) and umbelliferone (UB), were isolated from Cortex Mori (CM). Their structures were elucidated by various spectroscopic analyses. Then, their effects on rat glomerular mesangial cells (RGMCs, HBZY-1) proliferation, hypertrophy, extracellular matrix (ECM) proliferation, expression of fibronectin, transforming growth factor-beta (TGF-ß), and connective tissue growth factor (CTGF) induced by high glucose were studied in vitro model of diabetic glomerulosclerosis. The results show that, CM, SP, and UB can inhibit the RGMCs proliferation to attenuate the ECM proliferation and cell hypertrophy, reduced the accumulation of ECM protein fibronectin, and lowered the expression of the key fibrosis factor TGF-ß and CTGF to inhibit the kidney fibrosis and thereby improved diabetic glomerulosclerosis. The two coumarins show great potentialities on treating diabetic glomerulosclerosis, but the animal experiment and mechanism is strongly needed for further proof.

Ziyuglycoside II exerts antiproliferative and antimetastasis effects on hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. Phytochemicals are important candidates for developing anticancer agents. Ziyuglycoside II is a major active compound of Sanguisorba officinalis, which exhibits antiproliferation activity in several cancers; however, its action in HCC remains unknown. In this study, we investigated the antitumor activity of ziyuglycoside II against HCC and explored the potential mechanisms. We found that ziyuglycoside II exerts significant inhibitory effects on the viability and clonogenic activity of HCC cells. The proliferation repression mediated by ziyuglycoside II was mainly due to increased apoptosis and reactive oxygen species accumulation, as well as a G0/G1 phase cell-cycle arrest. Additionally, ziyuglycoside II markedly impaired HCC cell migration and invasion, two important steps during metastasis, and these suppressive effects may be attributed to the downregulation of matrix metalloproteinases MMP2 and MMP9 expression. Moreover, ziyuglycoside II blocked the epidermal growth factor receptor/nuclear factor kappa-B (EGFR/NF-kB) signaling, which may contribute to its anticancer activity. Taken together, our findings reveal antiproliferative and antimetastasis activities of ziyuglycoside II in HCC cells, implying that ziyuglycoside II might be a promising candidate for the development of novel anti-HCC drugs.

Kuwanon G Preserves LPS-Induced Disruption of Gut Epithelial Barrier In Vitro.

Defects in the gut epithelial barrier have now been recognized to be responsible for diabetic endotoxemia. In everyday life, Mulberry leaf tea is widely used in Asian nations due to its proposed benefits to health and control of diabetes. Evidence indicates the potential role of Kuwanon G (KWG), a component from Morus alba L., on blocking the gut epithelial barrier. In lipopolysaccharides (LPS)-damaged Caco-2 cells, it was found that KWG increased the viability of cells in a concentration-dependent manner. KWG administration significantly elevated the anti-oxidant abilities via increasing ratio of superoxidase dismutase (SOD)/malondialdehyde (MDA) and decreasing reactive oxygen species (ROS) within the cells. During KWG incubation, pro-inflammatory cytokines including interleukin (IL)-1ß and tumor necrosis factor (TNF)-α were significantly reduced, tight junction proteins including zonula occludens (ZO)-1, intercellular adhesion molecule (ICAM)-1 and Occludin were dramatically increased as detected by immunofluorescence assay, trans-epithelial electrical resistance was significantly increased and the transmission of albumin-fluorescein isothiocyanate (FITC) across the barrier was decreased. In conclusion, the present study demonstrated that KWG could ameliorate LPS-induced disruption of the gut epithelial barrier by increasing cell viability and tight junction between cells, and decreasing pro-inflammatory cytokines and oxidative damage.

3,3'-((3,4,5-trifluoropHenyl)methylene)bis(4-hydroxy-2H-chromen-2-one) inhibit lung cancer cell proliferation and migration.

Lung cancer is a major public health challenge and, despite therapeutic improvements, is the first leading cause of cancer worldwide. The current cure rate from advanced cancer treatment is excessively low. Therefore, it is of great importance to identify novel, potent and less toxic anticancer agents for the treatment of lung cancer. The aim of our research is to synthesize a new biscoumarin 3,3'-((3,4,5-trifluorop -phenyl)methylene)bis(4-hydroxy-2H-chromen-2-one) (C35) as an anticancer agent. C35 was simply prepared by 4-hydroxycoumarin and 3,4,5-trifluorobenzaldehyde under ethanol and its structure was analyzed by spectroscopic analyses. The anti-proliferation effect of C35 was detected using CCK-8 assay. Migration abilities were measured by Transwell assay. The expression of correlated proteins was determined by Western blot. The results showed that C35 displayed strong cytostatic effects on lung cancer cell proliferation. In addition, C35 possessed a significant inhibition of migration by reducing the expression of matrix metalloproteinases-2 (MMP-2) and MMP-9 in lung cancer cells. Furthermore, C35 treatment suppressed the phosphorylation of p38 in lung cancer cells. Moreover, in vivo experiments were carried out, in which we treated Lewis tumor-bearing C57 mice via intraperitoneal injection of C35. Results showed that C35 inhibited tumor growth in vivo. In conclusion, our study demonstrated the anticancer activity of C35 via suppression of lung cancer cell proliferation and migration, which is possibly involved with the inhibition of the p38 pathway.

Determination of Nitric Oxide-Derived Nitrite and Nitrate in Biological Samples by HPLC Coupled to Nitrite Oxidation.

Nitrite and nitrate are main stable products of nitric oxide, a pivotal cellular signaling molecule, in biological fluids. Therefore, accurate measurement of the two ions is profoundly important. Nitrite is difficult to be determined for a larger number of interferences and unstable in the presence of oxygen. In this paper, a simple, cost-effective and accurate HPLC method for the determination of nitrite and nitrate was developed. On the basis of the reaction that nitrite is oxidized rapidly to nitrate with the addition of acidic potassium permanganate, the determination of nitrite and nitrate was achieved by the following strategy: each sample was injected twice for HPLC analysis, i.e. the first injection was to measure nitrate, and the second injection was to measure total nitrate including initial nitrate and the nitrate from the conversion of nitrite with the addition of acid potassium permanganate in the sample. The amount of nitrite can be calculated as difference between injections 2 and 1. The HPLC separation was performed on a reversed phase C18 column for 15 min. The mobile phase consisted of methanol-water (2:98 by volume); the water in the mobile phase contained 0.60 mM phosphate salt (potassium dihydrogen and disodium hydrogen phosphate) and 2.5 mM tetrabutylammonium perchlorate (TBAP). The UV wavelength was set at 210 nm. Additionally, we systemically investigated the effects of the concentration of phosphate salt and TBAP in the mobile phase, the pH of the mobile phase, and the amount of acidic potassium permanganate added to the sample on the separation efficacy. The results showed that the limits of detection (LOD) and the limit of quantitation (LOQ) were 0.075 and 0.25 µM for nitrate (containing the oxidized nitrite), respectively. The linear range was 1-800 µM. This developed approach was successfully applied to assay nitrite/nitrate levels in cell culture medium, cell lysate, rat plasma and urine.

Development of self-microemulsifying drug delivery system for oral bioavailability enhancement of berberine hydrochloride.

The purpose of this study was to develop a self-microemulsifying drug delivery system (SMEDDS) to improve the oral bioavailability of Berberine hydrochloride (BBH), an important bioactive compound from Chinese Medicines with poor water solubility. Pseudoternary phase diagrams were constructed using oil, surfactant and co-surfactant types to identify the efficient self-microemulsification region. SMEDDS was characterized by morphological observation, droplet size, zeta-potential determination, stability, in vitro release and in vivo bioavailability study. The optimal formulation with the best self-microemulsifying and solubilization ability consisted of 40% (w/w) of ethyl linoleate and oleic acid (2:1), 35% (w/w) Tween-80 and 25% (w/w) glycerol. The SMEDDS of BBH could exhibit good stability. In vitro release test showed a complete release of BBH from SMEDDS was in 5 h. In vivo results indicated that the peak plasma concentration (C(max)) and the area under the curve (AUC(0→12 h)) of SMEDDS of BBH were higher than the commercial tablet by 163.4% and 154.2%, respectively. The relative bioavailability of SMEDDS of BBH was enhanced about 2.42-fold compared with the commercial tablet in rats. The study confirmed that the SMEDDS formulation could be used as a possible alternative to traditional oral formulations of BBH to improve its bioavailability.

Preventative effects of 4,4'-diphenylmethane-bis(methyl) carbamate isolated from cortex mori on human umbilical vein endothelial cell dysfunction induced by advanced glycation end products.

Advanced glycation end-products (AGEs) have been regarded as an initial motivating factor in the pathogenesis of endothelial dysfunction in diabetic complications. 4,4'-Diphenylmethane-bis(methyl) carbamate (DMPC), a carbamate compound, was isolated from Cortex Mori and its prevention effects against AGEs-induced endothelial dysfunction were studied. 4,4'-Diphenylmethane-bis(methyl) carbamate significantly reduced cell apoptosis to normal level at 10⁻9 mol/L concentration. Advanced glycation end-products up-regulated the expression of Bad and Bax and down-regulated Bcl-2 proteins, and pretreatment with DMPC significantly down-regulated Bad and Bax while up-regulating Bcl-2 expressions. In addition, ICAM (intercellular adhesion molecule)-1 and TGF (transforming growth factor)-ß1 expressions in human umbilical vein endothelial cell (HUVEC) were significantly enhanced by AGEs. More importantly, these increases of ICAM-1 and TGF-ß1 expressions were reduced meaningfully with the pretreatment of DMPC. All the results showed DMPC had prevention effects against the progression of AGE-induced endothelial dysfunction, and this compound might be a promising agent against endothelial dysfunction in diabetic vascular complications.

Phytoestrogen calycosin-7-O-ß-D-glucopyranoside ameliorates advanced glycation end products-induced HUVEC damage.

Vasculopathy including endothelial cell (EC) apoptosis and inflammation contributes to the high incidence of stroke and myocardial infarction in diabetic patients. The aim of the present study was to investigate the effect of calycosin-7-O-ß-D-glucopyranoside (CG), a phytoestrogen, on advanced glycation end products (AGEs)-induced HUVEC damage. We observed that CG can significantly ameliorate AGEs-induced HUVEC oxidative stress and apoptosis. The ratio of SOD/MDA was significantly increased to the normal level by CG pretreatment. CG preincubation dramatically increased anti-apoptotic Bcl-2 while decreased pro-apoptotic Bax and Bad expressions as detected by immunocytochemistry. Moreover, CG ameliorated macrophage migration and adhesion to HUVEC; the monocyte chemotactic protein-1 and interleukin-6 levels in the culture supernatant were dramatically reduced by CG as determined by ELISA; the expressions of inflammatory proteins including ICAM-1, TGF-ß1, and RAGE in both protein and mRNA levels were significantly reduced to the normal level by CG pretreatment as determined by immunocytochemistry and real-time RT-PCR. The intracellular investigation suggests that CG can reverse AGEs-activated ERK1/2 and NF-κB phosphorylation, in which estrogen receptors were involved in. Our results strongly indicate that CG can modulate EC dysfunction by ameliorating AGEs-induced cell apoptosis and inflammation.

Inhibitory effects of two major isoflavonoids in Radix Astragali on high glucose-induced mesangial cells proliferation and AGEs-induced endothelial cells apoptosis.

Radix Astragali, the dried roots of Astragalus membranaceus var. mongholicus, is well known to have a protective effect on diabetic nephropathy. However, the effects of isoflavonoids in Radix Astragali on glomerular cells, which play a key role in the development of diabetic vascular complications, remain largely unknown. Thus, the purpose of this study was to investigate in vitro the effect of calycosin and calycosin-7-O-ß-D-glucoside, two major isoflavonoids in Radix Astragali, on high glucose-induced rat mesangial cells proliferation and AGEs-induced human glomerular endothelial cell apoptosis. The results indicated that both calycosin and calycosin-7-O-ß-D-glucoside (10-100 µM) could inhibit high glucose-induced mesangial cell early proliferation. Additionally, AGEs-mediated cell apoptosis was also attenuated by treatment of glomerular endothelial cells with either calycosin or calycosin-7-O-ß-D-glucoside (1-100 µM). Therefore, the results obtained in this study suggest that both calycosin and calycosin-7-O-ß-D-glucoside have a significant therapeutic potential to modulate the development and/or progression of diabetic nephropathy.

Ethanol extract of Ophiorrhiza pumila suppresses liver cancer cell proliferation and migration.

BACKGROUND: Ophiorrhiza pumila, belonging to the genus Ophiorrhiza (Rubiaceae), is distributed throughout tropical and subtropical Asia. In this study, we evaluated for the first time the anti-proliferation and anti-migration effects of ethanol extract of O. pumila (OPE) on HepG2 and SMMC-7721 cells, and explored the related mechanism. METHODS: OPE was prepared by percolation with 95% ethanol and its main compounds were analyzed by HPLC-MS2. The anti-proliferation effect of OPE was evaluated by the CCK-8 assay and colony formation assay. Cell cycle distribution, apoptosis, and reactive oxygen species (ROS) level were detected by flow cytometry. Migration and invasion abilities were detected by Transwell migration/invasion assays. The expression of correlated proteins was determined using western blotting. RESULTS: A total of 5 tentative compounds were identified from OPE, including pumiloside, deoxypumiloside, camptothecin, aknadinine, and ß-stigmasterol. OPE displayed strong cytostatic effects on HepG2 and SMMC-7721 cells. OPE induced G2/M phase cell cycle arrest, increased apoptosis, and augmented ROS production in these cell lines. In addition, OPE possessed a significant inhibition on cell migration and invasion by reduction of MMP-9 and MMP-2 expression. Moreover, OPE significantly suppressed the phosphorylation of p65. CONCLUSIONS: Our data showed that OPE suppresses liver cancer cell proliferation and migration, which is possibly involved with the inhibition of the NF-κB pathway.

Screening bioactive components of Glycyrrhiza uralensis Fisch. with isolated perfused lung extraction and HPLC-ESI-MSn analysis.

The isolated perfused rat lung (IPL), coupled with high performance liquid chromatography\tandem mass spectrometry analysis (HPLC-ESI-MSn), has been developed as a tool for screening bioactive components in Glycyrrhiza uralensis Fisch. (GU). First, IPL was perfused with the water extract of GU (EGU), the bioactive components in the EGU would selectively combine to the receptors or channels of lung. By changing the pH of perfused solution, the combined components were eluated and then detected by HPLC-ESI-MSn. Four compounds were detected in the desorption eluate of IPL, among these compounds, liquiritin (1), ononin (2) and glycyrrhizic acid (4) were identified by comparing with the chromatography of the standards, while licorice-saponin G2 (3) were determined by analysis of the structure clearage characterization of mass spectrometry. Then, due to the lack of compound 3 sample, compounds 1, 2 and 4 with respective concentrations of 50 µM, 5 µM, 500 nM, 50 nM and 5 nM were applied to evaluate the protective effect of pulmonary epithelial cells (PEC, A549 cell) injury induced by lipopolysaccharide (LPS) for anti-inflammatory activity assessment. The results showed that except the 5 nM group of compound 1, 5 nM and 50 nM groups of compound 2, all other groups could remarkably inhibit the PEC injury (vs LPS group, 2-500 nM groups: p < 0.05; other groups: p < 0.01), all compound showed the dose-dependent effect. In conclusion, IPL coupled with HPLC-ESI-MSn was successfully used to screen the anti-inflammatory components of GU for the first time. The application of IPL coupled with HPLC-ESI-MSn for screening bioactive components of TCMs is rapid, convenient and reliable, and the isolated perfused technology could be extended to isolated heart, liver, kidney, and so on.

Shengui Sansheng San extraction is an angiogenic switch via regulations of AKT/mTOR, ERK1/2 and Notch1 signal pathways after ischemic stroke.

BACKGROUND: As a traditional Chinese herbal formula, Shengui Sansheng San (SSS) has been employed for stroke treatment more than 300 years. PURPOSE: We hypothesize that SSS extraction is an angiogenic switch in penumbra post-stroke, and corresponding mechanisms are investigated. METHODS: In present study, rats were subjected to permanent middle cerebral artery occlusion model (MCAo) and were treated with low, middle and high doses of SSS extraction. We assessed neurological function and survival rate, and measured infarct volume by 2,3,5-triphenyltetrazolium chloride staining on day 7 after ischemia. von Willebrand factor (vWF), stromal cell-derived factor-1 alpha (SDF-1α) /chemokine (C-X-C motif) receptor 4 (CXCR4) axis, vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR2) as well as protein kinase B (AKT)/mammalian target of rapamycin (mTOR) /hypoxia-inducible factor-1 alpha (HIF-1α), extracellular signal-regulated kinase 1/2 (ERK1/2) and Notch1 signaling pathways were respectively investigated by immunofluorescence assay or western blotting in vivo and oxygen-glucose-deprived (OGD) brain microvascular endothelial cells (BMECs); simultaneously, wound healing of BMECs and tube formation assay were administrated. RESULTS: Compared to MCAo group, SSS extraction could significantly improve neurological functional scores, survival rate and cerebral infarct volume, enhance vWF+ vascular density and perimeter, SDF-1α/CXCR4 axis, VEGF expression, as well as activate AKT/mTOR/HIF-1α and ERK1/2 and inhibit Notch1 pathways in penumbra. In vitro, containing SSS extraction serum increased BMEC migration, capillary formation and VEGF expression via up-regulations of AKT/mTOR and ERK1/2 pathways in OGD BMECs, but ERK inhibitor (U0126) reversed the result of VEGF expression in high dose of SSS group. Additionally, VEGFR2 and Notch1 expressions were suppressed by containing SSS extraction serum. All results were in dose dependent manner. CONCLUSION: Our study firstly demonstrates that SSS extraction is an angiogenic switch. Due to suppressed VEGFR2/Notch1 cascades and activated AKT/mTOR and ERK1/2 signals in BMECs, a feedback loop of angiogenic homeostasis is established. Furthermore, the comprehensive mediations of SDF-1α/CXCR4 axis, AKT/mTOR/HIF-α, ERK1/2 and Notch1 pathways in penumbra contribute to the improvements of neurological function, survival rate and infarct volume post-stroke.

The C-terminal tails of 4,4'-diphenylmethane-bis(methyl) carbamate are essential for binding to receptor for advanced glycation end products to attenuate advanced glycation end products-induced inflammation and apoptosis responses in human umbilical vein endothelial cells.

OBJECTIVES: A novel compound 4,4'-diphenylmethane-bis(methyl) carbamate (CM1) was shown to possess preventive activity on AGEs-induced human umbilical vein endothelial cells (HUVECs) damage via binding to RAGE. However, the underlying structural basis of CM1 on binding to RAGE was not fully understood. METHODS: In the present study, CM1 analogues were designed and synthesized to compare the activity differences on inhibiting AGEs-induced inflammatory response including TGF-ß1, RAGE protein expression in HUVECs, and macrophages migration and adhesion to HUVECs. In addition, the cell viability and anti-apoptosis activities of CM1 analogues were also examined. KEY FINDINGS: These results indicated that CM1 had higher activities on preventing AGEs-induced HUVECs damage (inflammation, cell viability and apoptosis) than other analogues. The bioaffinity assay was conducted by CMC and demonstrated that the IC50 and dissociation equilibrium constants (Kd) of CM1 were lower whereas the Bmax was higher than other analogues. The incubation of RAGE protein with CM1 analogues by equilibrium dialysis method showed CM1 had a stronger binding rate than other CM1 analogues. CONCLUSION: Our findings suggested that the C-terminal tails (methoxycarbonyl groups) of CM1 were the active groups for binding to RAGE and then led to the attenuation on RAGE-mediated endothelial dysfunction.

Calycosin Rebalances Advanced Glycation End Products-Induced Glucose Uptake Dysfunction of Hepatocyte In Vitro.

Diabetes mellitus (DM) often accompanies liver dysfunction. Astragali Radix is a traditional Chinese herbal medicine that is widely administrated to ameliorate the symptoms of diabetes as well as liver dysfunction, but its acting mechanism is still not yet fully recognized. Advanced glycation end products (AGEs) play a key role in promoting diabetic organ dysfunction. Both hyperglycemia and AGEs can induce insulin resistance, hepatocyte damage and liver dysfunction. We designed this study to explore the effects of the phytoestrogen Calycosin, a major active component of Astragali Radix, on AGEs-induced glucose uptake dysfunction in the hepatocyte cell line and relevant mechanisms. MTT and BrdU methods were applied to evaluate cell viability. 2-NBDG was used to observe glucose uptake by a live cell imaging system. Immunofluorescence method was carried out to investigate GLUT1, GLUT4, and RAGE protein expressions on cell membrane. cAMP content was determined by an EIA method. We found Calycosin concentration-dependently ameliorated AGEs-induced hepatocyte viability damage. AGEs dramatically reduced basal glucose uptake in hepatocytes, and this reduction could be reversed by Calycosin administration. By immunofluorescence detection, we observed that Calycosin could inhibit AGEs-induced GLUT1 expression down-regulation via estrogen receptor (ER). Furthermore, Calycosin decreased AGEs-promoted RAGE and cAMP elevation in hepatocytes. These findings strongly suggest that Calycosin can ameliorate AGEs-promoted glucose uptake dysfunction in hepatocytes; the protection of cell viability and ER-RAGE and GLUT1 pathways play a significant role in this modulation.

Antiviral activity of Isatis indigotica root-derived clemastanin B against human and avian influenza A and B viruses in vitro.

Clemastanin B, 7S,8R,8'R-(-)-lariciresinol-4,4'-bis-O-ß-D-glucopyranoside, is one of the major lignans extracted from Isatis indigotica root (IIR). In this study, the anti-influenza activities of clemastanin B were evaluated in vitro. Clemastanin B was found to inhibit different subtypes of human (H1N1, including swine-origin H1N1; H3N2 and influenza B) and avian influenza viruses (H6N2, H7N3, H9N2) at different magnitudes of activity (IC50 0.087-0.72 mg/ml) while this compound was inactive against respiratory syncytial virus (RSV), adenovirus 3 (ADV3), parainfluenza virus 3 (PIV3), enterovirus 71 (EV71) and human rhinovirus (HRV). An apparent virus titer reduction was detected when MDCK cells were treated with clemastanin B after viral infection, particularly at the early stage, and the ribonucleoprotein (RNP) of the influenza virus was retained in the nucleus after treatment with clemastanin B. These results demonstrated that clemastanin B targets viral endocytosis, uncoating or RNP export from the nucleus. Furthermore, treatment with clemastanin B did not easily result in the emergence of viral drug resistance. The effects of clemastanin B demonstrated in this study may promote the antiviral study of IIR, but additional studies are required to define the anti-influenza mechanism(s).

Macrophage biospecific extraction and HPLC-ESI-MSn analysis for screening immunological active components in Smilacis Glabrae Rhizoma.

A cell-permeable membrane, as typified by Transwell insert Permeable Supports, permit accurate repeatable invasion assays, has been developed as a tool for screening immunological active components in Smilacis Glabrae Rhizoma (SGR). In this research, components in the water extract of SGR (ESGR) might conjugate with the receptors or other targets on macrophages which invaded Transwell inserts, and then the eluate which contained components biospecific binding to macrophages was identified by HPLC-ESI-MS(n) analysis. Six compounds, which could interact with macrophages, were detected and identified. Among these compounds, taxifolin (2) and astilbin (4) were identified by comparing with the chromatography of standards, while the four others including 5-O-caffeoylshikimic acid (1), neoastilbin (3), neoisoastilbin (5) and isoastilbin (6), were elucidated by their structure clearage characterizations of tandem mass spectrometry. Then compound 1 was isolated and purified from SGR, along with 2 and 4, was applied to the macrophage migration and adhesion assay in HUVEC (Human Umbilical Vein Endothelial Cells) -macrophages co-incultured Transwell system for immunological activity assessment. The results showed that compounds 1, 2 and 4 with concentration of 5µM (H), 500nM (M) and 50nM (L) could remarkably inhibit the macrophage migration and adhesion (Vs AGEs (Advanced Glycation End Produces) group, 1-L, 2-H and 4-L groups: p<0.05; other groups: p<0.01). Moreover, 1 and 4 showed satisfactory dose-effect relationship. In conclusion, the application of macrophage biospecific extraction coupled with HPLC-ESI-MS(n) analysis is a rapid, simple and reliable method for screening immunological active components from Traditional Chinese Medicine.

Pre-column incubation followed by fast liquid chromatography analysis for rapid screening of natural methylglyoxal scavengers directly from herbal medicines: case study of Polygonum cuspidatum.

Methylglyoxal (MGO), a very reactive metabolite of glucose, plays a pivotal role in the pathogenesis of several chronic diseases associated with diabetes, and it has been validated as an attractive target for them. In the present study, a simple and effective method, namely pre-column incubation followed by fast high performance liquid chromatography based on superficially porous particles (shell), coupled with diode array detection and tandem mass spectrometry (UHPLC-DAD-MS(n)), was proposed for rapid and high-throughput screening of natural MGO scavengers directly from the crude extract of Polygonum cuspidatum Sieb. et Zucc, a well-known traditional Chinese medicine which was used for treatment of diabetic complications. The hypothesis is that upon reaction with MGO, the peak areas of components with MGO scavenging potency in the chromatogram will be significantly reduced or disappear, and the structural characterization could be achieved by UHPLC-DAD-MS(n) hyphenated technique. First of all, 12 compounds in P. cuspidatum were well separated within shorter time (~12 min) than previous methods and identified, and two of them, i.e. 3,5,4'-trihydroxystilbene-3-O-(6″-galloyl)-glucoside (3) and emodin-8-O-(6'-malonyl)-glucoside (8) were firstly reported ingredients. After incubation with MGO, four stilbene derivatives were demonstrated to possess potential MGO trapping activities. Furthermore, it was proved that both polydatin (piceid) and resveratrol exhibited effective MGO-trapping capacity by UHPLC analysis, and they could significantly inhibit the formation of advanced glycation end products (AGEs) in the human serum albumin (HSA)-MGO assay, indicating that they were potential candidate agents for delaying and preventing diabetic complications. Additionally, MGO trapping mechanism exploration by UHPLC-MS(n) showed that the positions 2 and 4 of the A ring of stilbene were major active sites for trapping MGO to form both mono- and di-MGO adducts, however, the glucosylation of the hydroxyl group would significantly decrease the trapping efficiency. Collectively, the current work provides a very promising method for rapid discovery of natural MGO scavengers directly from complex matrices such as herbal medicines with huge resources.

Competitive binding between 4,4'-diphenylmethane-bis(methyl) carbamate and RAGE ligand MG-H1 on human umbilical vein endothelial cell by cell membrane chromatography.

The compound 4,4'-diphenylmethane-bis(methyl) carbamate (CM1) has a protective activity on AGEs-induced endothelial dysfunction on human umbilical vein endothelial cell (HUVEC) in our previous study. It suggested that CM1 which may act as a competitive antagonist to the blockade of AGEs to receptor of AGEs (RAGE) and attenuate the HUVEC damage. In order to testify that hypothesis, the cell membrane chromatography (CMC) combined with high performance liquid chromatography (HPLC) was developed for analyzing the competitive binding properties on RAGE of HUVEC between CM1 and MG-H1, the agonist of RAGE. The results from saturation binding of CM1 and MG-H1 on cells demonstrated that dissociation equilibrium constants (K(d)) of CM1 and MG-H1 were 3.653 nM and 4.12 nM, respectively; while maximum binding capacity (B(max)) of CM1 and MG-H1 were 30.08 and 18.72 fmol/mg protein, respectively. In competition experiments, IC50 of CM1 with pre-incubation 10⁻¹° M and 10⁻9 M MG-H1 were 1.37 × 10⁻9 M and 4.56 × 10⁻8 M, respectively. The present findings indicated that CM1 conjugated competitively to cells with RAGE ligand MG-H1. The primary study illustrated that CMC combined with HPLC analysis method could be an alternative, rapid and efficient approach for the interaction of drug molecule and receptor, and that CM1 intervene the AGEs inducing HUVEC damage may via the competitively block the AGEs-RAGE path way.