Therapeutic Potential of Cinnoline Core: A Comprehensive Review.

Cinnoline or Benzo-pyridazine has its place in the family of fairly well-known benzfuseddiazine heterocycles. Because of its natural occurrence and synthetic exploration, cinnoline compounds validated its thought-provoking bioactivity through a number of research publications and patents during last few decades. A creative consideration has been rewarded to the synthesis of cinnoline based heterocyclic compounds, mostly due to their wide range of diverse pharmacological activities. The present review covers the principle approaches to the synthesis of cinnoline nucleus and almost all biological properties of 115 cinnoline derivatives reported during the last 65 years from natural and synthetic origin with 140 references.

Non-Curcuminoids from Turmeric and Their Potential in Cancer Therapy and Anticancer Drug Delivery Formulations.

Over the past decades curcuminoids have been extensively studied for their biological activities such as antiulcer, antifibrotic, antiviral, antibacterial, antiprotozoal, antimutagenic, antifertility, antidiabetic, anticoagulant, antivenom, antioxidant, antihypotensive, antihypocholesteremic, and anticancer activities. With the perception of limited toxicity and cost, these compounds forms an integral part of cancer research and is well established as a potential anticancer agent. However, only few studies have focused on the other bioactive molecules of turmeric, known as non-curcuminoids, which are also equally potent as curcuminoids. This review aims to explore the comprehensive potency including the identification, physicochemical properties, and anticancer mechanism inclusive of molecular docking studies of non-curcuminoids such as turmerones, elemene, furanodiene (FN), bisacurone, germacrone, calebin A (CA), curdione, and cyclocurcumin. An insight into the clinical studies of these curcumin-free compounds are also discussed which provides ample evidence that favors the therapeutic potential of these compounds. Like curcuminoids, limited solubility and bioavailability are the most fragile domain, which circumscribe further applications of these compounds. Thus, this review credits the encapsulation of non-curcuminoid components in diverse drug delivery systems such as co-crystals, solid lipid nanoparticles, liposomes, microspheres, polar-non-polar sandwich (PNS) technology, which help abolish their shortcomings and flaunt their ostentatious benefits as anticancer activities.

Lead compounds and key residues of ribosomal protein S1 in drug-resistant Mycobacterium tuberculosis.

Ribosomal protein S1 (RpsA) has been identified as a novel target of pyrazinoic acid (POA), which is the active form of pyrazinamide (PZA), in vivo. RpsA plays a crucial role in trans-translation, which is widespread in microbes. In our investigation, we first described the discovery of promising RpsA antagonists for drug-resistant mycobacterium (MtRpsAd438A) and M. smegmatis, as well as wild-type M. tuberculosis. These antagonists were discovered via structure/ligand-based virtual screening approaches. A total of 21 targeted compounds were selected by virtual screening, combined scores, affinity, similarities and rules for potential as drugs. Next, the affinities of these compounds for three targeted proteins were tested in vitro by applying various technologies, including fluorescence quenching titration (FQT), saturation transfer difference (STD), and chemical shift perturbation (CSP) assays. The results showed that seven compounds had a high affinity for the targeted proteins. Our discovery set the stage for discovering new chemical entities (NCEs) for PZA-resistant tuberculosis and providing key residues for rational drug design to target RpsA.

Synthesis and Biological Evaluation of Pyrimidine-oxazolidin-2-arylimino Hybrid Molecules as Antibacterial Agents.

Pyrimidine-1,3-oxazolidin-2-arylimino hybrids have been synthesized as a new class of antibacterial agents. The synthetic approach exploits a Cu(II)-catalyzed intramolecular halkoxyhalogenation of alkynyl ureas, followed by a Suzuki coupling reaction with 2,4-dimethoxypyrimidin-5-boronic acid. Biological screenings revealed that most of the compounds showed moderate to good activity against two Gram-positive (B. subtilis, S. aureus) and three Gram-negative (P. aeruginosa, S. typhi, K. pneumonia) pathogenic strains. A molecular docking study, performed in the crystal structure of 50S ribosomal unit of Haloarcula marismortui, indicated that pyrimidine-oxazolidin-2-arylimino hybrids 8c and 8h exhibited a high binding affinity (-9.65 and -10.74 kcal/mol), which was in agreement with their good antibacterial activity. The obtained results suggest that the combination of pyrimidine and oxazolidone moieties can be considered as a valid basis to develop new further modifications towards more efficacious antibacterial compounds.

Discovery of the Soluble Guanylate Cyclase Stimulator Vericiguat (BAY 1021189) for the Treatment of Chronic Heart Failure.

The first-in-class soluble guanylate cyclase (sGC) stimulator riociguat was recently introduced as a novel treatment option for pulmonary hypertension. Despite its outstanding pharmacological profile, application of riociguat in other cardiovascular indications is limited by its short half-life, necessitating a three times daily dosing regimen. In our efforts to further optimize the compound class, we have uncovered interesting structure-activity relationships and were able to decrease oxidative metabolism significantly. These studies resulting in the discovery of once daily sGC stimulator vericiguat (compound 24, BAY 1021189), currently in phase 3 trials for chronic heart failure, are now reported.

Combined effects of furanodiene and doxorubicin on the migration and invasion of MDA-MB-231 breast cancer cells in vitro.

Furanodiene is one of the major bioactive components isolated from the natural product of the plant, Curcuma wenyujin Y.H. Chen et C. Ling. Furanodiene has been found to exert anticancer effects in various types of cancer cell lines, as well as exhibit antimetastatic activities. However, the antimetastatic capacity of furanodiene in combination with the common chemotherapy drug doxorubicin has not been investigated. We found that doxorubicin at a non-toxic concentration induced cell migration and cell invasion in highly metastatic breast cancer cells. Combinational treatments with furanodiene and doxorubicin blocked the invasion and migration of MDA-MB-231 breast cancer cells in vitro. We also clarified the effects of the combination on the signaling pathways involved in migration, invasion, and cytoskeletal organization. When combined with doxorubicin, furanodiene downregulated the expression of integrin αV and ß-catenin and inhibited the phosphorylation of paxillin, Src, focal adhesion kinase (FAK), p85, and Akt. Moreover, combinational treatments also resulted in a decrease in matrix metalloproteinase-9 (MMP-9). Further study demonstrated that the co-treatments with furanodiene did not significantly alter the effects of doxorubicin on the tubulin cytoskeleton, represented by no influence on the expression levels of RhoA, Cdc42, N-WASP, and α/ß tubulin. These observations indicate that furanodiene is a potential agent that may be utilized to improve the anticancer efficacy of doxorubicin and overcome the risk of chemotherapy in highly metastatic breast cancer.

Structure activity relationship of pyridoxazinone substituted RHS analogs of oxabicyclooctane-linked 1,5-naphthyridinyl novel bacterial topoisomerase inhibitors as broad-spectrum antibacterial agents (Part-6).

Oxabicyclooctane linked 1,5-naphthyridinyl-pyridoxazinones are novel broad-spectrum bacterial topoisomerase inhibitors (NBTIs) targeting bacterial DNA gyrase and topoisomerase IV at a site different than quinolones. Due to lack of cross-resistance to known antibiotics they present excellent opportunity to combat drug-resistant bacteria. A structure activity relationship of the pyridoxazinone moiety is described in this Letter. Chemical synthesis and activities of NBTIs with substitutions at C-3, C-4 and C-7 of the pyridoxazinone moiety with halogens, alkyl groups and methoxy group has been described. In addition, substitutions of the linker NH proton and its transformation into amide analogs of AM-8085 and AM-8191 have been reported. Fluoro, chloro, and methyl groups at C-3 of the pyridoxazinone moiety retained the potency and spectrum. In addition, a C-3 fluoro analog showed 4-fold better oral efficacy (ED50 3.9 mg/kg) as compared to the parent AM-8085 in a murine bacteremia model of infection of Staphylococcus aureus. Even modest polarity (e.g., methoxy) is not tolerated at C-3 of the pyridoxazinone unit. The basicity and NH group of the linker is important for the activity when CH2 is at the linker position-8. However, amides (with linker position-8 ketone) with a position-7 NH or N-methyl group retained potency and spectrum suggesting that neither basicity nor hydrogen-donor properties of the linker amide NH is essential for the activity. This would suggest likely an altered binding mode of the linker position-7,8 amide containing compounds. The amides showed highly improved hERG (functional IC50 >30 µM) profile.

Design and synthesis of constrained analogs of LCRF-0004 as potent RON tyrosine kinase inhibitors.

New fused bicyclic lactam head groups as rigidified analogs of thieno[3,2-b]pyridine-based kinase inhibitor LCRF-0004 were designed and synthesized. Depending on the functionalities and the size of these bicyclic head groups, potent inhibitors of RON tyrosine kinase with various level of selectivity against c-Met tyrosine kinase were obtained.

Discovery and SAR of novel series of imidazopyrimidinones and dihydroimidazopyrimidinones as positive allosteric modulators of the metabotropic glutamate receptor 5 (mGlu5).

We report the discovery and SAR of two novel series of imidazopyrimidinones and dihydroimidazopyrimidinones as metabotropic glutamate receptor 5 (mGlu5) positive allosteric modulators (PAMs). Exploration of several structural features in the western and eastern part of the imidazopyrimidinone core and combinations thereof, revealed compound 4a as a mGlu5 PAM with good in vitro potency and efficacy, acceptable drug metabolism and pharmacokinetic (DMPK) properties and in vivo efficacy in an amphetamine-based model of psychosis. However, the presence of CNS-mediated adverse effects in preclinical species precluded any further in vivo evaluation.

Development of (E)-2-((1,4-dimethylpiperazin-2-ylidene)amino)-5-nitro-N-phenylbenzamide, ML336: Novel 2-amidinophenylbenzamides as potent inhibitors of venezuelan equine encephalitis virus.

Venezuelan equine encephalitis virus (VEEV) is an emerging pathogenic alphavirus that can cause significant disease in humans. Given the absence of therapeutic options available and the significance of VEEV as a weaponized agent, an optimization effort was initiated around a quinazolinone screening hit 1 with promising cellular antiviral activity (EC50 = 0.8 µM), limited cytotoxic liability (CC50 > 50 µM), and modest in vitro efficacy in reducing viral progeny (63-fold at 5 µM). Scaffold optimization revealed a novel rearrangement affording amidines, specifically compound 45, which was found to potently inhibit several VEEV strains in the low nanomolar range without cytotoxicity (EC50 = 0.02-0.04 µM, CC50 > 50 µM) while limiting in vitro viral replication (EC90 = 0.17 µM). Brain exposure was observed in mice with 45. Significant protection was observed in VEEV-infected mice at 5 mg kg(-1) day(-1) and viral replication appeared to be inhibited through interference of viral nonstructural proteins.

Drug design for neuropathic pain regulation from traditional Chinese medicine.

FAAH-like anandamide transporter (FLAT) regulates anandamide transport for hydrolysis and may be an attractive drug target for pain regulation. We aimed to discover potential FLAT antagonists from traditional Chinese medicine (TCM) using virtual screening, ligand-based drug design and molecular dynamics simulation (MD). Guineensine and Retrofractamide A exhibited high Dock Scores in FLAT. Consensus from multiple linear regression (MLR; R(2) = 08973) and support vector machine (SVM; R(2) = 0.7988) showed similar bioactivities for Guineensine and the FAAH-1 inhibitor (9Z)-1-(5-pyridin-2-yl-1,3,4-oxadiazol-2-yl)octadec-9-en-1-one. Contour of Guineensine to CoMFA and CoMSIA features also imply bioactivity. MD revealed shake or vibration in the secondary structure of FLAT complexed with Guineensine and (9Z)-1-(5-pyridin-2-yl-1,3,4-oxadiazol-2-yl)octadec-9-en-1-one. Ligand movement might contribute to protein changes leading to vibration patterns. Violent vibrations leading to an overall decrease in FLAT function could be the underlying mechanism for Guineensine. Here we suggest Guineensine as a drug-like compound with potential application in relieving neuropathic pain by inhibiting FLAT.

Analysis of volatile components in Curcuma rhizome by microemulsion electrokinetic chromatography.

Volatile chemicals are a group of very important compounds in natural products. Curcuma rhizome, which contains many bioactive volatile compounds, is a traditional Chinese medicine that has long been used for the treatment of several diseases. In the present study, a microemulsion electrokinetic chromatography (MEEKC) method was developed for the analysis of four volatile components in Curcuma rhizome, including germacrone, furanodiene, curcumenol and curdione. Experimental parameters, including the pH, type and concentrations of background electrolyte, and microemulsion compositions (type and concentrations of surfactant, co-surfactant and oil phase) were intensively investigated. Finally, the primary compounds in the methanol extract of Curcuma rhizome were separated within 30 min using a running buffer composed of 2.31% w/v (80 mmol/L) sodium dodecyl sulfate (SDS), 0.91% w/v (80 mmol/L) 1-octane, 6.95% w/v (937.5 mmol/L) 1-butanol and 1.88% w/v (312.5 mmol/L) propanol in a 5-mM borate buffer (pH 8.1). The contents of the four investigated compounds were determined in the rhizome from C. phaeocaulis. The results showed that the developed MEEKC method provided an alternative tool for the analysis of volatile components, especially those of heat-sensitive compounds from natural products.

A new conjugated amide-dimer from the aerial parts of Piper submultinerve.

Bioassay-guided fractionation and purification of the aerial parts of Piper submultinerve led to the isolation of a new conjugated amide-dimer, submultinamide A (1), along with 11 known compounds. The structures were determined on the basis of spectroscopic methods. Among the tested compounds, pellitorine (2), guineensine (4), N-benzylcinnamide (6) and aristolactam BII (8) showed significant activities in the anti-syncytium assay using (ΔTat/Rev)MC99 virus and 1A2 cell line system, whereas 2 was most active (EC50 35.1 µM and selectivity index 4.7). In the HIV-1 reverse transcriptase assay, only 4 was active with IC50 50.8 µM.

Heterocyclic compounds and aromatic diglycosides from Bretschneidera sinensis.

Two new heterocyclic compounds, bretschneiderazines A and B (1, 2), three new aromatic diglycosides, bretschneiderosides A-C (3-5), and three known aromatic diglycosides, 6-8, were isolated from Bretschneidera sinensis. The structure of bretschneiderazine A (1) was confirmed by single-crystal X-ray diffraction analysis. Bretschneiderazine A (1) showed moderate activity against the NCI-H446 cell line.

Identification and characterization of a small molecule inhibitor of Fatty Acid binding proteins.

Molecular disruption of the lipid carrier AFABP/aP2 in mice results in improved insulin sensitivity and protection from atherosclerosis. Because small molecule inhibitors may be efficacious in defining the mechanism(s) of AFABP/aP2 action, a chemical library was screened and identified 1 (HTS01037) as a pharmacologic ligand capable of displacing the fluorophore 1-anilinonaphthalene 8-sulfonic acid from the lipid binding cavity. The X-ray crystal structure of 1 bound to AFABP/aP2 revealed that the ligand binds at a structurally similar position to a long-chain fatty acid. Similar to AFABP/aP2 knockout mice, 1 inhibits lipolysis in 3T3-L1 adipocytes and reduces LPS-stimulated inflammation in cultured macrophages. 1 acts as an antagonist of the protein-protein interaction between AFABP/aP2 and hormone sensitive lipase but does not activate PPARgamma in macrophage or CV-1 cells. These results identify 1 as an inhibitor of fatty acid binding and a competitive antagonist of protein-protein interactions mediated by AFABP/aP2.

Serratezomines D and E, new Lycopodium alkaloids from Lycopodium serratum var. serratum.

Two new Lycopodium alkaloids, serratezomines D (1) and E (2), were isolated from the club moss Lycopodium serratum var. serratum. Serratezomine D (1) is a new lucidine-type alkaloid, while serratezomine E (2) is a new phlegmarane-type alkaloid. The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. Serratezomine D (1) exhibited an inhibitory activity against acetylcholinesterase.

Rengyolone inhibits apoptosis via etoposide-induced caspase downregulation.

In the course of screening for substances inhibiting apoptosis of U937 human leukemia cells induced by etoposide (10 microg/ml), Forsythiae fructus, which showed a high level of inhibition, was selected. The regulating compounds were purified from the ethyl acetate extract by silica gel column chromatography and HPLC. The active substance was purified and identified as rengyolone by spectroscopic methods. This compound showed inhibitory activity on caspase-3 induction, a major protease of the apoptosis cascade, with an IC50 value of 38.96 microM after 8 h of etoposide treatment in U937 cells. The expression level of caspase-3 and poly(ADP-ribose) polymerase (PARP) were dose-dependently inhibited by the compound, suggesting that rengyolone inhibits etoposide-induced apoptosis via downregulation of caspases.

Sesquiterpenes from Curcuma comosa.

From the dried rhizomes of Curcuma comosa cultivating in Thailand, 26 known sesquiterpenes were isolated: zederone, zederone epoxide, furanodienone, isofuranodienone, 1(10)Z,4Z-furanodiene-6-one, glechomanolide, dehydrocurdione, neocurdione, curdione, 7 alpha-hydroxyneocurdione, 7 beta-hydroxycurdione, germacrone-1(10),4-diepoxide, germacrone, 13-hydroxygermacrone, curzerenone, curcolonol, alismol, alismoxide, zedoarondiol, isozedoarondiol, procurcumenol, isoprocurcumenol, aerugidiol, zedoalactone B, curcumenone, and curcumadione. Their structures were elucidated on the basis of physicochemical evidence. Among them, glechomanolide, curzerenone, curcolonol, alismol, alismoxide, and zedoarondiol showed no significant optical activities, so they may be artifact products during the isolation or drying process.

Preclinical pharmacokinetics and metabolism of a novel diaryl pyrazole resorcinol series of heat shock protein 90 inhibitors.

CCT018159 was recently identified as a novel inhibitor of heat shock protein (Hsp) 90, a promising target for cancer therapy. Pharmacokinetic and metabolic properties are likely to be important for efficacy and need to be optimized during drug development. Here, we define the preclinical metabolism and pharmacokinetics of CCT018159 and some early derivatives. In addition, we assess in vitro metabolic stability screening and in vivo cassette dosing (simultaneous administration of several compounds to a single animal) as approaches to investigate these compounds. The plasma clearance following individual i.v. administration to mice was rapid (0.128-0.816 L/h), exceeding hepatic blood flow. For CCT066950 and CCT066952, this could be attributed in part to extensive (>80%) blood cell binding. Oral bioavailability ranged from 1.8% to 29.6%. Tissue distribution of CCT066952 was rapid and moderate, and renal excretion of the compounds was minimal (<1% of dose excreted). Compounds underwent rapid glucuronidation both in vivo and following incubation with mouse liver microsomes. However, whereas CCT066965 was metabolized to the greatest extent in vitro, this compound displayed the slowest plasma clearance. The rank order of the compounds from the highest to lowest area under the curve was the same following discrete and cassette dosing. Furthermore, pharmacokinetic variables were similar whether the compounds were dosed alone or in combination. We conclude that the pharmacokinetics of CCT018159 are complex. Cassette dosing is currently the best option available to assess the pharmacokinetics of this promising series of compounds in relatively high throughput and is now being applied to identify compounds with optimal pharmacokinetic properties during structural analogue synthesis.

Enantio- and diastereoselective total synthesis of EI-1941-1, -2, and -3, inhibitors of interleukin-1beta converting enzyme, and biological properties of their derivatives.

[reaction: see text] The first asymmetric total synthesis of EI-1941-1, -2, and -3, inhibitors of the interleukin-1beta converting enzyme (ICE), has been accomplished, starting from a chiral epoxy iodoquinone 11, a key intermediate in our total synthesis of epoxyquinols A and B. Despite a failure to synthesize the inhibitors by our postulated biosynthetic route, we were able to diastereoselectively synthesize them via an intramolecular carboxypalladation with the key steps being a 6-endo cyclization mode followed by beta-hydride elimination. The investigation of the biological properties of EI-1941-1, -2, and -3 and their derivatives disclosed them to be potent and effective ICE inhibitors with less cytotoxicity than EI-1941-1 and -2 in a cultured cell system.