Evaluation of the new anti-inflammatory compound ethyl salicylate 2-O-β-d-glucoside and its possible mechanism of action

Ethyl salicylate 2-O-β-d-glucoside (ESG) is a derivative of natural salicylate isolated from Gaultheria yunnanensis (Franch.) Rehder, it has been used for the treatments of rheumatoid arthritis, swelling and pain. The aim of this study was to evaluate the anti-inflammatory effects of ESG and explore the anti-inflammatory mechanisms. We found that ESG had potent anti-inflammatory effects on the lipopolysaccharide (LPS)-activated murine macrophages RAW264.7. ESG exerted a dose-dependent inhibition of the LPS-stimulated release of the pro-inflammatory cytokines TNF-α and IL-1β. Moreover, it significantly inhibited LPS-stimulated the production of NO and PGE₂ by repressing the expression of iNOS and COX protein respectively. Western blot analysis showed that ESG prominently inhibited LPS-induced activation of NF-κB in RAW264.7 cells by blocking phosphorylation of inhibitor IκBα and p65. Consistent with these results, we found that ESG prevented the nuclear translocation of NF-κB induced by LPS. Our study suggests that ESG may be effective in the treatment of inflammatory diseases by inhibiting the pro-inflammatory cytokine production and regulating the NF-κB signal pathway.     

Biochemical Characterization of the SPATE Members EspPα and EspI

The activity of serine proteases is influenced by their substrate specificity as well as by the physicochemical conditions. Here, we present the characterization of key biochemical features of the two SPATE members EspPα and EspI from Shiga-toxin producing Escherichia coli (STEC) and enterohemorrhagic E. coli (EHEC). Both proteases show high activity at conditions mimicking the human blood stream. Optimal activities were observed at slightly alkaline pH and low millimolar concentrations of the divalent cations Ca²⁺ and Mg²⁺ at physiological temperatures indicating a function in the human host. Furthermore, we provide the first cleavage profile for EspI demonstrating pronounced specificity of this protease.     

Evaluation of antioxidant and antigenotoxic activity of two flavonoids from Rhamnus alaternus L. (Rhamnaceae): Kaempferol 3-O-β-isorhamninoside and rhamnocitrin 3-O-β-isorhamninoside

The antioxidant activity of kaempferol 3-O-β-isorhamninoside (K3O-ir) and rhamnocitrin 3-O-β-isorhamninoside (R3O-ir), isolated from the leaves of Rhamnus alaternus L., was determined by the ability of each compound to inhibit NBT photoreduction and to scavenge the free radical ABTS⁺. Genotoxic and antigenotoxic activities were assessed using the SOS chromotest.At a concentration of 150 μg/assay the two compounds showed the most potent inhibitory activity against superoxide anion by respectively 80.4% and 85.6%. K3O-ir was a very potent radical scavenger with an IC₅₀ value of 18.75 μg/ml. Moreover, these two compounds exhibit an inhibitory activity against genotoxicity induced by nitrofurantoine and aflatoxine B1 using the SOS chromotest bacterial assay system in the presence of Escherichia coli PQ37 strain.In this study, we have also evaluated correlation between antigenotoxic and antioxidant effects of K3O-ir and R3O-ir. The highest correlation was showed with R3O-ir (r = 0.999).     

Emodin-6-O-β-d-glucoside inhibits HMGB1-induced inflammatory responses in vitro and in vivo

High mobility group box 1 (HMGB1) protein acts as a potent proinflammatory cytokine and is involved in the pathogenesis of several vascular diseases, such as, systemic vasculitis and sepsis. Emodin-6-O-β-d-glucoside (EG) is a new active compound from Reynoutria japonica, and its biologic activities have not been previously investigated. In this study, we first investigated the antiinflammatory activities of EG on HMGB1-mediated proinflammatory responses in human umbilical vein endothelial cells (HUVECs) and in a murine cecal ligation and puncture (CLP)-model of sepsis in mice. EG was found to suppress the release of HMGB1, the production of tumor necrosis factor (TNF)-α, and the activation of nuclear factor-κB (NF-κB) by HMGB1 in HUVECs, and to inhibit HMGB1-mediated hyperpermeability and leukocyte migration in mice. In the CLP model, HMGB1 was highly released, but this release was prevented by EG. Furthermore, EG also increased the survival times of CLP administered mice. Collectively, this study shows EG can protect barrier integrity and inhibit HMGB1-mediated inflammatory responses, which suggests a potential use as a therapy for sepsis or septic shock.     

A convenient semisynthesis of myricetin-3-O-β-d-glucuronide

Myricetin-3-O-β-d-glucuronide, a bioactive flavonol glycoside, was synthesized effectively starting from myricetrin in a total yield of 49.2%. The structures of all synthetic compounds were confirmed by ¹H, ¹³C NMR, and HR-MS techniques.     

Polymorphs and permeability of 3',4'-dimethoxy flavonol-3-O-β-D-glucopyranoside monohydrate

3',4'-Dimethoxy-flavonol-3-O-β-D-glucopyranoside monohydrate (GDH), which can significantly reduce blood lipids, atherosclerotic aortic lesions, and liver injury, has poor oral bioavailability. In the present study, we aimed to prepare and characterize five new polymorphs of GDH (II, III, IV, V, and VI) and the amorphous form of GDH (GDH-AM). The GDH polymorphs and GDH-AM were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray powder diffraction (XRPD), and Fourier transform infrared spectroscopy (FTIR). Dissolution tests, physical stability, polymorphic transformation, and permeability studies were subsequently investigated. Dissolution of GDH-II and GDH-IV reached higher concentrations compared with GDH-I. GDH-AM exhibited a significantly high dissolution rate and prolonged supersaturation during dissolution. No phase transition was found for GDH-I and GDH-AM after 3 months of storage, while GDH-II, GDH-III, GDH-IV, GDH-V, and GDH-VI were readily converted to GDH-I. In situ single-pass intestinal perfusion experiments showed that the high concentration of GDH exhibited low permeability. Sodium dodecyl sulfate and bovine bile salts were used as absorption enhancers to improve the permeability of GDH. The results showed that sodium dodecyl sulfate and taurocholate were good absorption enhancers for further formulation development of GDH.     

Physcion and physcion 8-O-β-glucopyranoside:a review of their pharmacology,toxicities and pharmacokinetics

Anthraquinones constitute an important class of natural and synthetic compounds with a broad scope of pharmacological including anti-bacterial, antioxidant, laxative, anti-tumor and other activities. Physcion and physcion 8-O-β-glucopyranoside(PG) are common anthraquinones existed in various plants. Emerging studies suggested that physcion and PG not only exert antitumor, anti-microbial, anti-inflammatory, anti-oxidant, optical-related, enzyme inhibitory, lipid regulation and neuroprotective activities, but also lead to hepatotoxicity, renal toxicity and genetic damage. Besides, a growing number of pharmacokinetics researches of physcion and PG also have been conducted. However, no review of physcion or PG have been published by now, so the aim of present review is to give a comprehensive summary and analysis of the pharmacology, toxicity and pharmacokinetics of physcion and PG by consulting all the currently available literatures published in Pub Med then give a future prospects about it.     

Structure Determination of Monohydrated Trifolin (Kaempferol 3-O-β-D-Galactopyranoside) from Laboratory Powder Diffraction Data

The crystal structure of monohydrated trifolin (kaempferol 3-O-β-D-galactopyranoside) (an important biologically active compound, which was isolated from the aerial part of Consolida oliveriana) has been determined from conventional laboratory X-ray powder diffraction data. Variable counting time technique was used during measurement and crystal structure was solved by means of Monte Carlo algorithm. The final structure was achieved by Rietveld refinement using both constraints and restraints on interatomic bond lengths and angles.     

Purification and Characterization of Hepatocyte Regeneration Stimulatory Factor from Shark Liver

Aim To purify hepatocyte regeneration stimulatory factor from shark liver and research its molecular feature and activity. Methods and Results Hepatocyte regeneration stimulatory factor (sHRSF) was isolated from healthy shark livers and separated by homogenization, freezing-melting, heat treating, centfifugation, and ultmfdwation. HRSF activity was found mainly in the subfraction of molecular weight less than 30 000 daltons. This crude ultrafihrate was further purified successively by DEAE-Sepharose fast flow chromatography, FPLC Resource 30Q, Resource Q and Mono Q chromatography.A single band was displayed on sodium dodecyl sulfate polyacrylamide gel electrophoresis, which corresponds to molecular weight of 14 600 daltons. The characteristic absorption was obtained at the wavelength 276 nm. The isoelectric point was about 5.1. It contained 18 amino acids and the 15 N-terminal amino acid residues were LVGPIGAVGPAGKDG. It had a significant activity in stimulating liver to regenerate. Condusion We obtained an unknown new active protein, that is hepatocyte regeneration stimulatory factor from shark liver ( sHRSF).     

Isolation, identification and antiviral activities of metabolites of calycosin-7-O-β-D-glucopyranoside

In vivo and in vitro metabolites of calycosin-7-O-β-d-glucopyranoside in rats were identified using a specific and sensitive high performance liquid chromatography-tandem mass spectrometry (HPLC-MSⁿ) method. The parent compound and twelve metabolites were found in rat urine after oral administration of calycosin-7-O-β-d-glucopyranoside. The parent compound and six metabolites were detected in rat plasma. In heart, liver, spleen, lung and kidney samples, respectively, six, eight, seven, nine and nine metabolites were identified, in addition to the parent compound. Three metabolites, but no trace of parent drug, were found in the rat intestinal flora incubation mixture and feces, which demonstrated cleavage of the glycosidic bond of the parent compound in intestines. The main phase I metabolic pathways of calycosin-7-O-β-d-glucopyranoside in rats were deglycosylation, dehydroxylation and demethylation reactions; phase II metabolism included sulfation, methylation, glucuronidation and glycosylation (probably). Furthermore, two metabolites commonly found in rat urine, plasma and tissues were isolated from feces and characterized by NMR. The antiviral activities of the metabolite calycosin against coxsackie virus B₃ (CVB₃) and human immunodeficiency virus (HIV) were remarkably stronger than those of calycosin-7-O-β-d-glucopyranoside.     

Thermal Analysis and Spectroscopic Characterization of Interactions Between a Naphthoquinone Derivative with HP-β-CD or PVP

The purpose of the present study was to investigate the interaction between both hydroxypropyl-β-cyclodextrin (HP-β-CD) and PVP-K30 with 2-hydroxy-N-(3-methyl-5-ethyl-4-isoxazolyl)-1,4-naphthoquinone-4-imina (I), a synthetic derivative of isoxazolylnaphthoquinones that has demonstrated to exhibit important biological activity against S. aureus and T. cruzi. The continuous variation plot for I–HP-β-CD system showed a 1:1 stoichiometry for the complex. Ultraviolet absorption spectroscopy indicates that the isoxazole moiety of I is preferably incorporated in the cavity. Furthermore, proton nuclear magnetic resonance spectroscopy suggests that this incorporation is made from the primary hydroxyl group side of the cyclodextrin. The validation of this incorporation is further evidenced by thermal analysis (DSC and TGA) and infrared spectroscopy. I–PVP-K30 interactions in solid state were demonstrated by combining the infrared spectroscopy data with the results of thermal analysis (DSC, TGA). These methods suggest that drug–polymer interaction probably occurs via intermolecular hydrogen bonding between the drug hydroxyl and polymer carbonyl groups.     

Synthesis and Characterization of a Cytotoxic Cationic Polyvinylpyrrolidone–Curcumin Conjugate

Curcumin has been studied as a potential drug for many diseases including cancer. One of the serious limitations projected on curcumin is its poor water solubility and the substantially low bioavailability. With a view to enhance the aqueous solubility of curcumin, we synthesized polyvinylpyrrolidone–curcumin conjugates. Polyvinylpyrrolidone was used for the conjugation considering its long history of safe usage as a biomaterial for various medical applications. The drug conjugates self-assembled in aqueous solution to form nanosized micellar aggregates. The formation of micellae stabilized curcumin against hydrolytic degradation. Another interesting feature of the conjugate was its cationic nature. The net zeta potential in the pH range from 3 to 7.4 was +25 to +20 mV, reflecting the potential stability of the conjugate micellae at physiological pH. We quantified cytotoxic potential of the conjugate by the MTT assay, using L929 fibroblast cells. The results showed that the conjugate had higher cytotoxicity than that of the free curcumin. It is expected that the relative enhanced cytotoxicities are the result of enhanced aqueous solubility and polymer-mediated drug internalization. The conjugate has the potential to circumvent limitations of curcumin and thereby to extrapolate further its applications as an effective anticancer drug.     

Isolation and Characterization of a Monomethioninesulfoxide Variant of Interferon α-2b

Purpose. To isolate and characterize a monomethioninesulfoxide variant of the commercially available therapeutic protein interferon -2b. Methods. The methionine (Met)-oxidized variant was isolated by reverse-phase high performance liquid chromatography and characterized by SDS-PAGE, peptide mapping and mass spectrometric analysis of the trypsin/V8-generated peptide fragments. The biological and immunological activities of the isolated variant were also evaluated. Results. The rHuIFN -2b variant was found to contain a Met sulfoxide residue at position 111 of the rHuIFN -2b molecule. The far-UV CD spectra showed a slight loss of -helical content and an increase in the -sheet contribution. The CD spectra indicate that both chromatographic conditions and Met oxidation contribute to the observed secondary structure changes. Both interferon -2b main component and its methionine-oxidized variant showed different reactivity to monoclonal antibodies employed in immunoassays for the protein. Conclusions. A monomethioninesulfoxide rHuIFN -2b variant was found to be present in the rHuIFN -2b bulk drug substance in solution. The Met¹¹¹ residue was identified as Met sulfoxide by comparative tryptic/V8 mapping and mass spectrometric analysis. Nevertheless, the oxidation of the Met¹¹¹ residue did not seem to have a detectable effect on the biological activity of the molecule.     

Characterization and in vitro dissolution behaviour of ketoconazole/β- and 2-hydroxypropyl-β-cyclodextrin inclusion compounds

The effect of β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin on the solubility of ketoconazole in different media were studied. A type A_L solubility diagram was obtained for ketoconazole and the two cyclodextrins in buffer solution, pH 5 and pH 6. The stability constants between ketoconazole and the two cyclodextrins were calculated from the phase solubility diagrams. Increased ionization of the imidazole derivative decreased the values of the stability constants. The formation of solid inclusion complexes were experimentally prepared by the kneading and spray-drying techniques. In order to confirm solid complex formation, X-ray diffractometry and differential scanning calorimetry were used. It was found that the spray-drying technique could be used to prepare the amorphous state of drug inclusion complexes. The dissolution rates of ketoconazole from the inclusion complex made by spray-drying were faster than the pure drug, kneading systems and the physical mixtures of drug and cyclodextrins. The enhanced dissolution rate of spray-dried products might be attributed to the decreased particle size, the high-energetic amorphous state and inclusion complex formation.     

Quercetin-3-O-β-d-glucuronide isolated from Polygonum aviculare inhibits cellular senescence in human primary cells

Cellular senescence is known to contribute to tissue aging, a variety of age-related diseases, tissue regeneration, and cancer. Therefore, aging intervention might be useful for prevention of aging as well as age-related disease. In this study, we investigated compounds from Polygonum aviculare to determine if they inhibited cellular senescence in human primary cells, human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs). Ten compounds from P. aviculare were purified and their inhibitory effects on adriamycin-induced cellular senescence were measured by observing senescence-associated β-galactosidase (SA-β-gal) activity and reactive oxygen species. Among them, compound 9 (quercetin-3-O-β-d-glucuronide) showed inhibitory effects against cellular senescence in HDFs and HUVECs treated with adriamycin. Additionally, compound 9 rescued replicative senescence in HDFs and HUVECs. These data imply that compound 9 represses cellular senescence in human primary cells and might be useful for the development of dietary supplements or cosmetics that ameliorate tissue aging or aging-associated diseases.     

2,3,4',5-Tetrahydroxystilbene-2-O-β-d-glucoside inhibits platelet-derived growth factor-induced proliferation of vascular smooth muscle cells by regulating the cell cycle

1. 2,3,4',5-Tetrahydroxystilbene-2-O-β-d-glucoside (TSG) has been shown to have an anti-atherosclerotic effect. Vascular smooth muscle cell (VSMC) proliferation contributes to the pathobiology of atherosclerosis. The aim of the present study was to investigate the effects of TSG on platelet-derived growth factor (PDGF)-BB-induced VSMC proliferation and to explore the molecular mechanisms underlying the effects. 2. Cultured rat VSMC were pretreated with TSG (l-50 μmol/L) for 1 h, followed by exposure to PDGF-BB (10 ng/mL) for 24 h, after which cell proliferation and cell cycle stages were examined. The expression of protein cell cycle regulators, including retinoblastoma (Rb), cyclin D1/E, cyclin-dependent kinase (CDK) 2/4, CDK inhibitors p21 and p27 and proliferative cell nuclear antigen (PCNA), was examined. Activation of extracellular signal-regulated kinase (ERK) 1/2 was evaluated to elucidate the possible upstream mechanism by which TSG affects cell cycle regulators. 3. The results showed that TSG dose-dependently inhibited PDGF-BB-induced VSMC proliferation, possibly by blocking the progression of the cell cycle from the G(1) to S phase. In addition, TSG significantly inhibited PDGF-BB-induced phosphorylation of Rb and the expression of cyclin D1, CDK4, cyclin E, CDK2 and PCNA. In addition, TSG suppressed PDGF-BB-induced downregulation of p27 and upregulation of p21, as well as PDGF-BB-induced activation of ERK1/2. 4. Together, the findings of the present study provide the first evidence that TSG can inhibit PDGF-BB-stimulated VSMC proliferation via cell cycle arrest in association with modulation of the expression of cell cycle regulators, which may be mediated, at least in part, by suppression of ERK1/2 activation.     

Production of a highly potent epoxide through the microbial metabolism of 3β-acetoxyurs-11-en-13β,28-olide by Aspergillus niger culture

Context 3β-Acetoxyurs-11-en-13β,28-olide (I), a triterpenoid, is found in most plant species. Pharmacologically triterpenes are very effective compounds with potent anticancer, anti-HIV and antimicrobial activities.

Objectives Microbial transformation of 3β-acetoxyurs-11-en-13β,28-olide (I) was performed in order to obtain derivatives with improved pharmacological potential.

Materials and methods Compound (I, 100?mg) was incubated with Aspergillus niger culture for 12 d. The metabolite formed was purified through column chromatography. Structure elucidation was performed through extensive spectroscopy (IR, MS and NMR). In vitro α- and β-glucosidase inhibitory, and antiglycation potentials of both substrate and metabolite were evaluated.

Results Structure of metabolite II was characterized as 3β-acetoxyurs-11,12-epoxy-13β,28-olide (II). Metabolite II was found to be an oxidized product of compound I. In vitro α- and β-glucosidases revealed that metabolite II was a potent and selective inhibitor of α-glucosidase (IC₅₀ value?=?3.56?±?0.38?μM), showing that the inhibitory effect of metabolite II was far better than compound I (IC₅₀ value?=?14.7?±?1.3?μM) as well as acarbose (IC₅₀ value?=?545?±?7.9?μM). Antiglycation potential of compound II was also high with 82.51?±?1.2% inhibition. Thus, through oxidation, the biological potential of the substrate molecule can be enhanced.

Conclusion Biotransformation can be used as a potential tool for the production of biologically potent molecules.     

The effect of luteolin-7-O-β-d-glucuronopyranoside on gastritis and esophagitis in rats

This study evaluated the inhibitory action of luteolin-7-O-beta-D-glucuronopyranoside, luteolin which was isolated from Salix gilgiana leaves, and omeprazole on reflux esophagitis and gastritis in rats. Reflux esophagitis and gastritis were induced surgically and by the administration of indomethacin, respectively. The intraduodenal administration of luteolin-7-O-beta-D-glucuronopyranoside decreased the ulcer index, injury area, gastric volume and acid output, and increased the gastric pH compared with luteolin. Luteolin-7-O-beta-D-glucuronopyranoside significantly decreased the size of the gastric lesions that had been induced by exposing the gastric mucosa to indomethacin. The malondialdehyde content, which is the end product of lipid peroxidation, was increased significantly after inducing of reflux esophagitis. The malondialdehyde content was decreased by Luteolin-7-O-beta-D-glucuronopyranoside but not luteolin or omeprazole. Luteolin-7-O-beta-D-glucuronopyranoside has a more potent antioxidative effect than luteolin. Luteolin-7-O-beta-D-glucuronopyranoside is a promising drug for the treatment of reflux esophagitis and gastritis.     

Isolation and Pharmacological Characterization of α-Elapitoxin-Ot1a,a Short-Chain Postsynaptic Neurotoxin from the Venom of the Western Desert Taipan,Oxyuranus temporalis

Taipans (Oxyuranus spp.) are elapids with highly potent venoms containing presynaptic (β) and postsynaptic (α) neurotoxins. O. temporalis (Western Desert taipan), a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components have been isolated from this venom. We describe the characterization of α-elapitoxin-Ot1a (α-EPTX-Ot1a; 6712 Da), a short-chain postsynaptic neurotoxin, which accounts for approximately 30% of O. temporalis venom. α-Elapitoxin-Ot1a (0.1–1 µM) produced concentration-dependent inhibition of indirect-twitches, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The inhibition of indirect twitches by α-elapitoxin-Ot1a (1 µM) was not reversed by washing the tissue. Prior addition of taipan antivenom (10 U/mL) delayed the neurotoxic effects of α-elapitoxin-Ot1a (1 µM) and markedly attenuated the neurotoxic effects of α-elapitoxin-Ot1a (0.1 µM). α-Elapitoxin-Ot1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA₂ value of 8.02 ± 0.05. De novo sequencing revealed the main sequence of the short-chain postsynaptic neurotoxin (i.e., α-elapitoxin-Ot1a) as well as three other isoforms found in O. temporalis venom. α-Elapitoxin-Ot1a shows high sequence similarity (i.e., >87%) with other taipan short-chain postsynaptic neurotoxins.