Design, synthesis, and anti-influenza A virus activity evaluation of novel indole containing derivatives of triazole.

We designed and synthesized 18 substituted indole derivatives containing a triazole scaffold as novel anti-influenza A virus candidates using a bio-isosteric and scaffold-hopping strategy from the lead compound 4-32-2. Most of the target compounds (eg: 6, 7a, 7d, 7f-j, 7l, 7m, 7o, 7q) exhibited potent anti-influenza A virus activity and low cytotoxicity in vitro. In particular, 7a exhibited the most potent anti-IAV activity (IC50: 1.34 ± 0.13 µM) with low cytotoxicity (CC50: > 100 µM), and high selectivity index (SI: > 74.63), which provides a new chemical scaffold for the development of novel anti-IAV drug.

Discovery of 1,8-naphthalidine derivatives as potent anti-hepatic fibrosis agents via repressing PI3K/AKT/Smad and JAK2/STAT3 pathways.

Liver fibrosis is one of the most common pathological consequences of chronic liver diseases (CLD). To develop effective antifibrotic strategies, a novel class of 1-(substituted phenyl)-1,8-naphthalidine-3-carboxamide derivatives were designed and synthesized. By means of the collagen type I α 1 (COL1A1)-based screening and cytotoxicity assay in human hepatic stellate cell (HSC) line LX-2, seven compounds were screened out from total 60 derivatives with high inhibitory effect and relatively low cytotoxicity for further COL1A1 mRNA expression analysis. It was found that compound 17f and 19g dose-dependently inhibited the expression of fibrogenic markers, including α-smooth muscle actin (α-SMA), matrix metalloprotein 2 (MMP-2), connective tissue growth factor (CTGF) and transforming growth factor ß1 (TGFß1) on both mRNA and protein levels. Further mechanism studies indicated that they might suppress the hepatic fibrogenesis via inhibiting both PI3K/AKT/Smad and non-Smad JAK2/STAT3 signaling pathways. Furthermore, 19g administration attenuated hepatic histopathological injury and collagen accumulation, and reduced fibrogenesis-associated protein expression in liver tissues of bile duct ligation (BDL) rats, showing significant antifibrotic effect in vivo. These findings identified 1,8-naphthalidine derivatives as potent anti-hepatic fibrosis agents, and provided valuable information for further structure optimization.

Design, synthesis, and antibacterial evaluation of PFK-158 derivatives as potent agents against drug-resistant bacteria.

Infections caused by antibiotic resistant bacteria are a major health concern throughout the world. It is well known that PFK-158 can enhance the antibacterial effect of polymyxin, but its own anti-bactericidal effect is rarely discussed. In order to investigate the anti-bactericidal effect of PFK-158 and its derivatives, PFK-158 and 35 derivatives were designed, synthesized, and evaluated for their antibacterial activities. Compounds A1, A3, A14, A15 and B6 exhibited potent antibacterial effect against both clinical drug sensitive and resistant Gram-positive bacteria, and they are 2-8 folds more potent than levofloxacin against Methicillin-resistant staphylococcus epidermidis (MRSE). A significant synergistic effect of these compounds and polymyxin against drug-resistant Gram-negative bacteria, which is similar to PFK-158 was also observed. The result can provided a new and broader prospect for the development of new medicine against drug-resistant bacteria.

Design, synthesis and biological evaluation of HIV-1 protease inhibitors with morpholine derivatives as P2 ligands in combination with cyclopropyl as P1' ligand.

A series of novel HIV-1 protease inhibitors has been designed and synthesized, which contained morpholine derivatives as the P2 ligands and hydrophobic cyclopropyl as the P1' ligand at the meantime in this study, with the aim of improving the interactions between the active sites of HIV-1 protease and the inhibitors. Twenty-eight compounds were synthesized and assessed, among which inhibitors m18 and m1 exhibited excellent inhibitory effect on the activity of HIV-1 protease with IC50 value of 47 nM and 53 nM, respectively. The molecular modeling of m1 revealed possible hydrogen bondings or van der Waals between the inhibitor and the protease, worthy of in-depth study.

Design, synthesis, and biological activity evaluation of a series of pleuromutilin derivatives with novel C14 side chains.

In this work, according to the 'me-too me-better' design strategy, a peculiar side chain different from lefamulin at C14 position of pleuromutilin was introduced. A series of novel thioether pleuromutilin derivatives containing cyclohexane in the C14 chain was synthesized by ten-step synthesis reaction. All derivatives were characterized by Nuclear Magnetic Resonance (NMR) and High Resolution Mass Spectrometer (HRMS). Furthermore, majority of derivatives displayed moderate antibacterial activity in vitro. However, the compound 2C and 2J exhibited comparable or superior antibacterial activity to lefamulin. The summarized structure-activity relationship not only made the variety of pleuromutilin derivatives more diverse, but also provided new ideas for its design and development.

A novel biphenyl compound IMB-S7 ameliorates hepatic fibrosis in BDL rats by suppressing Sp1-mediated integrin αv expression.

Chronic tissue injury with fibrosis results in the disruption of tissue architecture, organ dysfunction, and eventual organ failure. Therefore, the development of effective antifibrotic drugs is urgently required. IMB-S7 is novel biphenyl compound derived from bifendate (biphenyldicarboxylate) that is used for the treatment of chronic hepatitis in China. In the current study we investigated the potential of IMB-S7 as an antihepatic fibrosis agent. In bile duct ligation (BDL) rat model, oral administration of IMB-S7 (400 mg· kg-1· d-1, for 14 days) significantly ameliorated BDL-induced liver necrosis, bile duct proliferation, and collagen accumulation. We then showed that IMB-S7 treatment markedly suppressed the TGF-ß/Smad pathway in human hepatic stellate cell line LX2 and mouse primary HSCs, as well as in liver samples of BDL rats, thus inhibiting the transcription of most fibrogenesis-associated genes, including TGF-ß1, COL1A1, and ACTA2. Furthermore, IMB-S7 treatment significantly suppressed the expression of integrin αv at the mRNA and protein levels in TGF-ß-treated LX2 cells and liver samples of BDL rats. Using integrin αv overexpression and silencing, we demonstrated that integrin αv activity correlated positively with the activation of TGF-ß/Smad pathway. Based on dual luciferase assay and DNA affinity precipitation assay, we revealed that IMB-S7 inactivated integrin αv through competitively inhibiting the binding of Sp1, a transcription factor, to the integrin αv (ITGAV) promoter (-173/-163 bp). These results suggest that IMB-S7 inhibits HSCs activation and liver fibrosis through Sp1-integrin αv signaling, and IMB-S7 may be a promising candidate to combat hepatic fibrosis in the future.

Synthesis and biological evaluation of new HIV-1 protease inhibitors with purine bases as P2-ligands.

Introducing purine bases to P2-ligands might enhance the potency of Human Immunodeficiency Virus-1 (HIV-1) protease inhibitory because of the carbonyl and NH groups promoting the formation of extensive H-bonding interactions. In this work, thirty-three compounds are synthesized and evaluated, among which inhibitors 16a, 16f and 16j containing N-2-(6-substituted-9H-purin-9-yl)acetamide as the P2-ligands along with 4-methoxylphenylsulfonamide as the P2'-ligand, display potent inhibitory effect on the activity of HIV-1 protease with IC50 43 nM, 42 nM and 68 nM in vitro, respectively.

Antibacterial Activity and Structure-Activity Relationship of a Series of Newly Synthesized Pleuromutilin Derivatives.

A series of novel thioether or sulfoxide-type pleuromutilin derivatives containing heteroaromatic substituents at the end of C14 side chain were designed and synthesized. All of the derivatives were evaluated for their in vitro antibacterial activity. Some of them showed good to excellent antibacterial activity comparable to retapamulin and azamulin in most of the tested Gram-positive pathogens. In this work, a five-membered heterocyclic moiety, a pyrimidine-heterocyclic moiety, or a benzoheterocyclic moiety was introduced in the C14 side chain to increase the structural diversity of the pleuromutilin derivatives. The antibacterial results reveal that the thioether-containing pleuromutilin derivatives exert a more potency activity than the sulfoxide-type derivatives against Gram-positive pathogens. The structure-activity relationship summarized in this work may provide with some interesting clues as to which functionalities are beneficial for high antimicrobial activity of the pleuromutilin derivatives.

Design, synthesis and biological evaluation of novel HIV-1 protease inhibitors with pentacyclic triterpenoids as P2-ligands.

The design, synthesis and SAR study of a new series of HIV-1 protease inhibitors with pentacyclic triterpenoids as P2 ligands and phenylsulfonamide as P2' ligands were discussed. These compounds exhibited micromolar inhibitory potency, among which compound T1c displayed HIV-1 protease inhibition with IC50 values of 0.12 µM, which was 67 times the inhibitory activity of its raw material Ursolic acid (8.0 µM).

A novel ASBT inhibitor, IMB17-15, repressed nonalcoholic fatty liver disease development in high-fat diet-fed Syrian golden hamsters.

The manipulation of bile acid (BA) homeostasis by blocking the ileal apical Na+-dependent bile salt transporter (ASBT/SLC10A2) may have therapeutic effects in nonalcoholic fatty liver disease. We developed a novel ASBT inhibitor, an N-(3,4-o-dichlorophenyl)-2-(3-trifluoromethoxy) benzamide derivative referred to as IMB17-15, and investigated its therapeutic effects and the molecular mechanisms underlying the effects. Syrian golden hamsters were challenged with high-fat diet (HFD) to induce NAFLD and were subsequently administered 400 mg/kg IMB17-15 by gavage daily for 21 days. Serum, liver, and fecal samples were collected for further analysis. Plasma concentration-time profiles of IMB17-15 were also constructed. The human hepatocyte cell line HL-7702 was treated with Oleic acid (OA) with or without IMB17-15. Western blotting and real-time PCR were used to study the molecular mechanisms of IMB17-15. We found that IMB17-15 inhibited ASBT and subsequently suppressed ileal farnesoid X receptor (FXR) and FXR-activated fibroblast growth factor15/19 (FGF15/19) expression, which reduced the hepatic phosphorylated extracellular regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) levels and upregulated the cholesterol 7α-hydroxylase (CYP7A1) activity. Additionally, IMB17-15 stimulated adenosine monophosphate (AMP)-activated protein kinase (AMPKα) phosphorylation and enhanced peroxisome proliferator activated receptor α (PPARα) expression and thus promoted triglyceride (TG) oxidation and high-density lipoprotein cholesterol (HDL-c) metabolism through an ASBT-independent mechanism. In conclusion, a novel ASBT inhibitor known as IMB17-15 protected hamsters against HFD-induced NFALD by manipulating BA and lipid homeostasis. IMB17-15 also reduced lipid deposition in human hepatic cell lines, indicating that it may be useful as a therapy for NAFLD patients.

A novel protein kinase inhibitor IMB-YH-8 with anti-tuberculosis activity.

Protein kinase B (PknB) is one of the Mycobacterium tuberculosis serine/threonine protein kinases and has an essential role in sustaining mycobacterial growth. Here, we identified and characterized a novel small molecule compound named IMB-YH-8 that inhibited PknB and served as anti-mycobacteria lead compound. IMB-YH-8 inhibited PknB auto-phosphorylation and the phosphorylation of GarA by PknB in a dose-dependent manner. The compound did not inhibit human Akt1 or other serine/threonine kinases in M. tuberculosis except for the highly homologous PknA. IMB-YH-8 bound to PknB with a moderate affinity. Molecular docking revealed that IMB-YH-8 interacts with the catalytic domain of PknB. Observations of electron microscopy showed that IMB-YH-8 changed the morphology of H37Rv and disrupted the cell wall. The differential transcriptional response of M. tuberculosis to IMB-YH-8 revealed changes in SigH regulatory pathways modulated by PknB. Notably IMB-YH-8 not only potently inhibited drug-sensitive and multidrug-resistant clinical isolates but also exhibited a dose dependent inhibition of intracellular M. tuberculosis. Taken together, these in vitro data demonstrate that IMB-YH-8 is a novel inhibitor of PknB, which potently prevents growth of M. tuberculosis. It is as yet unclear whether inhibition of PknA contributes to the anti-tubercular action of IMB-YH-8.

[Advances in studies of ileal apical sodium-dependent bile acid transporter].

Bile acids play critical roles in the regulation of metabolism and absorption of lipids. The ileal apical sodium-dependent bile acid transporter (ASBT) located at the enterocyte brush border is responsible for the reuptake of bile acids and the maintenance of bile acid homeostasis. Recently, a number of investigations have been made concerning the regulation and control of ASBT and the relationship between ASBT and intestinal inflammation, tumorigenesis, diabetes mellitus and hyperlipemia, which suggests ASBT as a potential therapeutic target of these diseases. In this review, advances in the study of above-mentioned issues were summarized.

Herbihabitans rhizosphaerae gen. nov., sp. nov., a member of the family Pseudonocardiaceae isolated from rhizosphere soil of the herb Limonium sinense (Girard).

The taxonomic position of an actinobacterium, designated CPCC 204279T, which was isolated from a rhizosphere soil sample of the herb Limonium sinense collected from Xinjiang Province, China, was established using a polyphasic approach. Whole-cell hydrolysates of strain CPCC 204279T contained galactose and arabinose as diagnostic sugars and meso-diaminopimelic acid as the diamino acid. The muramic acid residues in the peptidoglycan were N-acetylated. The predominant menaquinone was MK-9(H4). The phospholipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The major fatty acids were iso-C16 : 0, iso-C16 : 0 2-OH, C16 : 1ω9c, iso-C16 : 1 and C16 : 0. The genomic DNA G+C content was 73.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CPCC 204279T should be placed in the family Pseudonocardiaceae, in which the strain formed a distinct lineage next to the genus Actinophytocola. Signature nucleotides in the 16S rRNA gene sequence showed that the strain contained the Pseudonocardiaceae family-specific 16S rRNA signature nucleotides and a genus-specific diagnostic nucleotide signature pattern. The combination of phylogenetic analysis and phenotypic characteristics supported the conclusion that strain CPCC 204279T represents a novel species of a new genus in the family Pseudonocardiaceae, for which the name Herbihabitans rhizosphaerae gen. nov., sp. nov. is proposed. Strain CPCC 204279T (=NBRC 111774T=DSM 101727T) is the type strain of the type species.

[Impurity analysis and quality evaluation for commercial levofloxacin formulations using LC-MS/MS method].

The study aims to develop a rapid, specific and sensitive method for quantitative analysis of trace impurities in levofloxacin formulation using LC-MS/MS. The quality of the different formulations from 19 plants was evaluated in the contents of the impurities. The results indicated that there were 5 impurities in the samples, and the content was different in the products with same formulation by different plants. The products of 3 plants were in good quality with impurities level under 0.01%. Levofloxacin N(4')-methyl quaternary impurity was first reported as the formulation impurity. The impurities were tightly correlated to the reservation of drug, process control of formulation and storage during transportation. The results suggest that our method is sensitive and specific to detect the trace impurities in formulation, and can be used to monitor the quality of commercial drug product.

[Establishment and application of a high-throughput drug screening model based on COL1A1 promoter for anti-liver fibrosis].

For screening the potential drugs as anti-liver fibrosis candidates, we established a high- throughput drug screening cell model based on COL1A1 promoter. The activity of COL1A1 promoter and luciferase reporter gene can be elevated by TGF-ß1, and inhibited by candidate drugs. We constructed a recombined plasmid with COL1A1 promoter and luciferase reporter gene pGL4.17, the activity of COL1A1 promoter was reflected by fluorescence intensity. COL1A1 promoter activity was detected by Dual-Luciferase Reporter Assay System, it came that the relative luciferase activity of COL1A1 promoter was 15.98 times higher than that of control group induced by TGF-ß1, showing the recombined plasmid could be used in cell model. The recombined plasmid was transfected into human hepatic stellate cells LX2, detected the effect of potential drugs, and obtained a stable expression system through stable transfection and monoclonal cell culture. A sample which could reduce COL1A1 promoter activity signally by our cell model, decreased collagen I mRNA and protein expression detected by real-time RT-PCR and Western blotting. It indicates this novel cell model can be used in high-throughput drug screening of potential anti-liver fibrosis drugs.

Synthesis and biological evaluation of novel HIV-1 protease inhibitors using tertiary amine as P2-ligands.

A series of tertiary amine derivatives exhibiting potent HIV-1 protease inhibiting properties were identified. These novel inhibitors were designed based on the structure of Darunavir with modification on the P2 and P2' position. This effort led to discovery of 35e and 38e, which exhibited excellent HIV-1 protease inhibition with IC50 values of 15 nM and 64 nM, respectively.

Synthesis and cytotoxic evaluation of alkoxylated chalcones.

A series of chalcones a1-20 bearing a 4-OMe groups on the A-ring were initially synthesized and their anticancer activities towards HepG2 cells evaluated. Subsequently, a series of chalcones b1-42 bearing methoxy groups at the 2' and 6'-positions of the B-ring were synthesized and their anticancer activities towards five human cancer cell lines (HepG2, HeLa, MCF-7, A549 and SW1990) and two non-tumoral human cell lines evaluated. The results showed that six compounds (b6, b8, b11, b16, b18, b22, b23 and b29) displayed promising activities, with compounds b22 and b29 in particular showing higher levels of activity than etoposide against all five cancer cell lines. Compound b29 showed a promising SI value compared with both HMLE and L02 (2.1-6.5 fold in HMLE and > 33 > 103.1 fold in L02, respectively).

Di-tert-butyl 1-[2-hy-droxy-3-(methyl-sulfan-yl)prop-yl]hydrazine-1,2-di-carboxyl-ate.

The title compound, C14H28N2O5S, was synthesized by the reaction of 2-[(methyl-sulfan-yl)meth-yl]oxirane with di-tert-butyl oxalate in hydrazine hydrate. In the crystal, mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds into supra-molecular chains propagating along the b-axis direction.

tert-Butyl N-[2-(N-isobutyl-4-meth-oxy-benzene-sulfonamido)-eth-yl]carbamate.

The title compound, C18H30N2O5S, was synthesized by the reaction of tert-butyl 2-(iso-butyl-amino)-ethyl-carbamate with p-meth-oxy-phenyl-sulfonyl chloride. In the mol-ecule, two intra-molecular C-H⋯O hydrogen bonds are observed. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds involving the imino group N atom and the ester group O atom into chains running parallel to the b axis. The chains are further connected by C-H⋯O hydrogen bonds, forming layers parallel to the bc plane.

An integrated approach for detection and characterization of the trace impurities in levofloxacin using liquid chromatography-tandem mass spectrometry.

RATIONALE: Impurity analysis plays an important role to guarantee the quality and safety of pharmaceuticals. However, identification of impurities remains challenging, especially for those unknown or at trace levels. We present an integrated approach to detect and characterize the trace impurities in drugs. METHODS: Based on liquid chromatography-tandem mass spectrometry (LC-MS/MS), an approach integrating automatic impurity screening method using multiple mass defect filters (MMDFs) and background subtraction (BS) was developed. This approach was used to acquire the structural and semi-quantitative information in a single sample run, and even to discover the impurity signals submerged by background and drug ions. This approach was illustrated by the comprehensive impurity analysis of levofloxacin. RESULTS: This approach was sensitive to detect impurities at the level of 0.02% with respect to levofloxacin concentration. Nineteen impurities were detected, fourteen of which were structurally characterized and eight impurities were reported for the first time. Impurity profiles of levofloxacin drug substances and degradation samples were obtained reliably. A plausible degradation pathway of levofloxacin was proposed including descarboxyl reaction under acid, piperazinyl ring cleavage degradation under light, and N-oxidation under oxidative condition. CONCLUSIONS: The generic approach integrating LC-MS/MS and an automatic impurity screening method was developed for the detection, characterization and monitoring of impurities, especially those unknown or at trace levels. This approach was demonstrated to be rapid, sensitive and automatic for impurity profiling of drugs.