An alternative route for tricyclic quinazolinone-iminosugars and their glucosidase inhibitory activities.

A series of novel tricyclic quinazolinone-iminosugars 5 and their derivatives 7 were obtained from the tosylated sugars by three steps. Firstly, the reaction of the isopropylidene protected sugar tosylate 1 and o-aminobenzylamine 2 generated the precursor tricyclic quinazolin-iminosuar 3, which was then oxidized by KMnO4 to produce the corresponding quinazolinone 4. Finally, removal of the isopropylidene group yielded the target tricyclic quinazolinone iminosugars 5. In addition, quinazolinone-iminosugars 4ac, 4bc and 4cc who contain bromine in the aromatic region underwent Suzuki reaction with phenylboronic acid, followed with the removal of the isopropylidene group to afford the derivatives 7. This strategy will help to construct such fused multicyclic quinazolinone-iminosugars efficiently. Some compounds show certain inhibition against α-glucosidase (saccharomyce cerevisiae).

Interaction between oxidised state of quercetin and bovine serum albumin in presence of surfactant aggregates with different charges.

The present investigation focuses on the role of surfactant and its charge on the interaction of flavonoid Quercetin (QCT) and Bovine serum albumin (BSA). QCT is known to undergo autoxidation in many chemical environments which has different characteristics compared to its non-oxidised structure. In this experiment, two ionic surfactants used. They are anionic surfactant, Sodium dodecyl sulfate (SDS) and Cationic surfactants Cetyl pyridinium bromide (CPB). The characterizations employed are conductivity, FT-IR, UV-visible spectroscopy, Dynamic light scattering (DLS) and Zeta potential measurements. The critical micellar concentration (CMC) as well as the counter-ion binding constant (ß) have been calculated by making use of specific conductance values, in aqueous medium at 300 K. Various thermodynamic parameters, ΔG0m, standard free energy of micellization, ΔH0m, standard enthalpy of micellization and ΔS0m, standard entropy of micellization are calculated. The negative value of ΔG0m in all systems is indicative of spontaneous binding occurring in both QCT + BSA + SDS (-23.35 kJ mol-1) and QCT + BSA + CPB (-27.18 kJ mol-1). The higher negative value infers the latter is a more stable system with greater spontaneity. The UV-visible spectroscopy study points at stronger binding of QCT and BSA in presence of surfactants and also there is stronger binding of CPB in ternary mixture with higher binding constant compared to SDS ternary mixture. Which is evident from the binding constant calculated from Benesi-Hildebrand plot (QCT + BSA + SDS, 244.46 M-1; QCT + BSA + CPB, 336.53 M-1). Further, the structural alterations occurring in the above systems has been observed by FT-IR spectroscopy. The DLS and Zeta potential measurements also support the above finding.Communicated by Ramaswamy H. Sarma.

Study on active components and mechanism of shikonin in prevention and treatment of blood heat syndrome / 中国药理学通报

Aim To systematically evaluate the heat-clearing mechanism of Arnebiae Radix on two mouse models of blood heat syndrome. Methods The drug-forming molecules were screened by comprehensive network pharmacology methods, and the correlation between drug efficacy and related factors and targets was evaluated on the mouse model of short effect blood heat syndrome constructed by 2, 4-dinitrophenol (DNP) and the mouse model of severe blood heat syndrome (heat stroke) constructed by high temperature combined with lipopolysaccharide (LPS). Results A total of 277 shikonin related targets were collected, mainly involving biological processes such as inflammatory reaction, oxidation reaction and coagulation reaction. Shikonin, a representative compound, significantly improved the main syndromes of mice with blood heat syndrome, reduced the levels of inflammatory factors IL-1β, IL-6 and TNF-α in the two models, and reduced the contents of oxidative damage indexes LPO and MDA, and the two showed correlation. The main mechanism was to inhibit the expression of NF-ΚB p65 and up-regulate the expression of Nrf2. Conclusions Shikonin plays a pharmacological role in the prevention and treatment of blood heat syndrome by inhibiting inflammation and improving antioxidant capacity, which provides a pharmacological basis for shikonin in the prevention and treatment of blood heat syndrome.

Improving the Stability of Protein-Protein Interaction Assay FlimPIA Using a Thermostabilized Firefly Luciferase.

The protein-protein interaction assay is a key technology in various fields, being applicable in drug screening as well as in diagnosis and inspection, wherein the stability of assays is important. In a previous study, we developed a unique protein-protein interaction assay "FlimPIA" based on the functional complementation of mutant firefly luciferases (Fluc). The catalytic step of Fluc was divided into two half steps: D-luciferin was adenylated in the first step, while adenylated luciferin was oxidized in the second step. We constructed two mutants of Fluc from Photinus pyralis (Ppy); one mutant named Donor is defective in the second half reaction, while the other mutant named Acceptor exhibited low activity in the first half reaction. To date, Ppy has been used in the system; however, its thermostability is low. In this study, to improve the stability of the system, we applied Fluc from thermostabilized Luciola lateralis to FlimPIA. We screened suitable mutants as probes for FlimPIA and obtained Acceptor and Donor candidates. We detected the interaction of FKBP12-FRB with FlimPIA using these candidates. Furthermore, after the incubation of the probes at 37°C for 1 h, the luminescence signal of the new system was 2.4-fold higher than that of the previous system, showing significant improvement in the stability of the assay.

Identification of functional cytochrome P450 and ferredoxin from Streptomyces sp. EAS-AB2608 by transcriptional analysis and their heterologous expression.

Bioconversion using microorganisms and their enzymes is an important tool in many industrial fields. The discovery of useful new microbial enzymes contributes to the development of industries utilizing bioprocesses. Streptomyces sp. EAS-AB2608, isolated from a soil sample collected in Japan, can convert the tetrahydrobenzotriazole CPD-1 (a selective positive allosteric modulator of metabotropic glutamate receptor 5) to its hydroxylated form at the C4-(R) position. The current study was performed to identify the genes encoding the enzymes involved in CPD-1 bioconversion and to verify their function. To identify gene products responsible for the conversion of CPD-1, we used RNA sequencing to analyze EAS-AB2608; from its 8333 coding sequences, we selected two genes, one encoding cytochrome P450 (easab2608_00800) and the other encoding ferredoxin (easab2608_00799), as encoding desirable gene products involved in the bioconversion of CPD-1. The validity of this selection was tested by using a heterologous expression approach. A bioconversion assay using genetically engineered Streptomyces avermitilis SUKA24 ∆saverm3882 ∆saverm7246 co-expressing the two selected genes (strain ES_SUKA_63) confirmed that these gene products had hydroxylation activity with respect to CPD-1, indicating that they are responsible for the conversion of CPD-1. Strain ES_SUKA_63 also showed oxidative activity toward other compounds and therefore might be useful not only for bioconversion of CPD-1 but also as a tool for synthesis of drug metabolites and in optimization studies of various pharmaceutical lead compounds. We expect that this approach will be useful for bridging the gap between the latest enzyme optimization technologies and conventional enzyme screening using microorganisms. KEY POINTS: • Genes easab2608_00800 (cyp) and easab2608_00799 (fdx) were selected by RNA-Seq. • Selection validity was evaluated by an engineered S. avermitilis expression system. • Strain ES_SUKA_63 showed oxidative activity toward CPD-1 and other compounds.

Anti-inflammatory mechanism of low dose methotrexate and its application in spinal cord injury / 中国药理学通报

Methotrexate (MTX)has dual effects of anti-inflam-matory and immune suppression,and its pharmacological mecha-nism is complex,diverse and synergistic.This paper summari-zes the main anti-inflammatory mechanism of low-dose MTX,in-cluding inhibition of JAK/STAT pathway,inhibition of inflam-matory reaction and immune response,increasing the accumula-tion of adenosine and the function of intracellular metabolites (methotrexate polyglutamate).In addition,low-dose MTX can inhibit oxidation by decreasing the level of lipid peroxidation, suppress the inflammatory response to secondary spinal cord in-jury,reduce spinal cord ischemia reperfusion injury and neuro-pathic pain,thus playing a neuroprotective role by a series of pharmacological mechanism.The anti-inflammatory mechanism of low-dose MTX and its application in spinal cord injury were reviewed,to guide the further research on the anti-inflammatory effect of MTX,and provide a theoretical basis for new drugs for clinical treatment of spinal cord injury.

Effect and Underlying Mechanism of Wuzhi Capsules in the Treatment of Vancomycin-induced Kidney In-jury in Rats / 中国药师

Objective:To explore the protective effect of Wuzhi capsules on vancomycin-induced kidney injury in rats and investi-gate the action mechanism. Methods:Totally 24 male SD rats were randomly divided into the blank control group,the model control group and the model test group with 8 ones in each. The rats in the model control group and the model test group were intravenously in-jected vancomycin via tail veil,200 mg·kg-1per day for 10 consecutive days,while those in the blank control group were injected sa-line at the same volume. Meanwhile,the rats were orally administered Wuzhi solution(0.25 g·kg-1) in the model test group and sa-line at the same volume in the blank control group and the model control group. The levels of 24-h microalbuminuria(MALB),neutro-phil gelatinase associated lipocalin(NGAL) and kidney injury molecule 1 (KIM-1) in urine were determined,and those of cystatin C (Cys C),serum creatinine (Scr) and blood urea nitrogen(BUN) in serum and those of superoxide dismutase(SOD),malondialde-hyde(MDA) and glutathione peroxidase(GSH-Px) in renal tissues were also determined. Results:The levels of the renal index,Cys C,Scr,BUN,MALB,NGAL,KIM-1 and MDA in the model control group and the model test group were significantly higher than those in the blank control group,and those in the model control group were significantly higher than those in the model test group(P<0.05 or P<0.01). The levels of SOD and GSH-Px in the model control group and the model test group were significantly lower than those in the blank control group,and those in the model control group were significantly lower than those in the model test group(P<0.05). Conclusion:Wuzhi capsules can effectively relieve vancomycin-induced renal injury in rats probably by inhibiting the oxida-tive reaction.

Nonvolatile Bipolar Resistive Switching Behavior in the Perovskite-like (CH3NH3)2FeCl4.

The bipolar resistive switching behavior in a device based on an crystalline iron-based organic-inorganic, perovskite-like material of (CH3NH3)2FeCl4 (MAFC), was examined and studied. Both high and low resistance states appeared to have no obvious degradation during a measurement period of 600 s with 400 cycles in a Ag/MAFC/Cu device, which also exhibited good thermal stability over a wide temperature range of 290 to 340 K. The conductivity-state switching behavior was derived from the competition between the ionic current within the MAFC and the Faradaic current that originated from oxidative reactions at the Ag/MAFC/Cu interface. A model explaining the oxidative reaction process was established to describe the symmetric resistive switching behavior in the Ag/MAFC/Cu cell. With an applied bias voltage sweeping, the oxidative layers passivated and dissipated at the Ag/MAFC/Cu interface that resulted in the competition between the induced current and the ionic current, and thus caused a symmetric resistance change. On the basis of this interfacial effect, the MAFC crystals can be used as memristor elements in devices for write-read-erase-rewrite process.

TiO2-sludge carbon enhanced catalytic oxidative reaction in environmental wastewaters applications.

The enhanced oxidative potential of sludge carbon/TiO2 nano composites (SNCs), applied as heterogeneous catalysts in advanced oxidation processes (AOPs), was studied. Fabrification of efficient SNCs using different methods and successful evaluation of their catalytic oxidative activity is reported for the first time. Surface modification processes of hydrothermal deposition, chemical treatment and sol-gel solution resulted in improved catalytic activity and good surface chemistry of the SNCs. The solids obtained after chemical treatment and hydrothermal deposition processes exhibit excellent crystallinity and photocatalytic activity. The highest photocatalytic rate was obtained for the material prepared using hydrothermal deposition technique, compared to other nanocomposites. Further, improved removal of bisphenol A (BPA) from aqueous phase by means of catalytic ozonation and catalytic wet air oxidation processes is achieved over the solid synthesized using chemical treatment method. The present results demonstrate that the addition of TiO2 on the surface of sludge carbon (SC) increases catalytic oxidative activity of SNCs. The latter produced from harmful sludge materials can be therefore used as cost-effective and efficient sludge derived catalysts for the removal of hazardous pollutants.