Catalytic Decarboxylative Radical Sulfinylation.

Sulfoxides are ubiquitous in both naturally and synthetically bioactive molecules. We report herein a redox-neutral and mild approach for radical sulfinylation of redox-active esters via dual photoredox and copper catalysis, furnishing a series of functionalized sulfoxides. The reaction could accommodate a range of tertiary, secondary, and primary carboxylic acids, as well as exhibit wide functional group compatibility. The chemistry features a high degree of practicality, is scalable, and allows late-stage modification of bioactive pharmaceuticals.

Necrostatin-1 Analog DIMO Exerts Cardioprotective Effect against Ischemia Reperfusion Injury by Suppressing Necroptosis via Autophagic Pathway in Rats.

AIM: It has been reported that necrostatin-1 (Nec-1) is a specific necroptosis inhibitor that could attenuate programmed cell death induced by myocardial ischemia/reperfusion (I/R) injury. This study aimed to observe the effect and mechanism of novel Nec-1 analog (Z)-5-(3,5-dimethoxybenzyl)-2-imine-1-methylimidazolin-4-1 (DIMO) on myocardial I/R injury. METHODS: Male SD rats underwent I/R injury with or without different doses of DIMO (1, 2, or 4 mg/kg) treatment. Isolated neonatal rat cardiomyocytes were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) treatment with or without DIMO (0.1, 1, 10, or 100 µM). Myocardial infarction was measured by TTC staining. Cardiomyocyte injury was assessed by lactate dehydrogenase assay (LDH) and flow cytometry. Receptor-interacting protein 1 kinase (RIP1K) and autophagic markers were detected by co-immunoprecipitation and Western blotting analysis. Molecular docking of DIMO into the ATP binding site of RIP1K was performed using GLIDE. RESULTS: DIMO at doses of 1 or 2 mg/kg improved myocardial infarct size. However, the DIMO 4 mg/kg dose was ineffective. DIMO at the dose of 0.1 µM decreased LDH leakage and the ratio of PI-positive cells followed by OGD/R treatment. I/R or OGD/R increased RIP1K expression and in its interaction with RIP3K, as well as impaired myocardial autophagic flux evidenced by an increase in LC3-II/I ratio, upregulated P62 and Beclin-1, and activated cathepsin B and L. In contrast, DIMO treatment reduced myocardial cell death and reversed the above mentioned changes in RIP1K and autophagic flux caused by I/R and OGD/R. DIMO binds to RIP1K and inhibits RIP1K expression in a homology modeling and ligand docking. CONCLUSION: DIMO exerts cardioprotection against I/R- or OGD/R-induced injury, and its mechanisms may be associated with the reduction in RIP1K activation and restoration impaired autophagic flux.

Copper-Catalyzed Remote C(sp3)-H Amination of Carboxamides.

Here we report a method for the site-selective intermolecular C(sp3)-H amination of carboxamides by merging transition-metal catalysis and the hydrogen atom transfer strategy. The reaction proceeds through a sequence of favorable single-electron transfer, 1,5-hydrogen atom transfer, and C-N cross-coupling steps, thus allowing access to a series of desired products. This reaction could accommodate a wide diversity of nitrogen nucleophiles as well as demonstrate excellent chemoselectivity and functional group compatibility.

Neuroprotective Effects of DTIO, A Novel Analog of Nec-1, in Acute and Chronic Stages After Ischemic Stroke.

Receptor-interacting protein 1 kinase (RIP1K) plays a key role in necroptosis. Necrostatin-1 (Nec-1), a specific inhibitor of RIP1K, provides neuroprotection against ischemic brain injury, associating with inhibition of inflammation. Recently, our group synthesized a novel analog of Nec-1, 5-(3',5'-dimethoxybenzal)-2-thio-imidazole-4-ketone (DTIO). The present study investigated the effect of DTIO on ischemic stroke-induced brain injury in both acute and chronic phase and its underlying mechanism. In vivo, DTIO treatment reduced infarct volume and improved neurological deficits in the acute phase after permanent middle cerebral artery occlusion (pMCAO) and it also attenuated brain atrophy and promoted brain functional recovery in the chronic phase post-cerebral ischemia/reperfusion (I/R). In vitro, DTIO treatment decreased lactate dehydrogenase (LDH) leakage and necrotic cell death in the oxygen and glucose deprivation (OGD) or oxygen and glucose deprivation and reoxygenation (OGD/R)-induced neuronal or astrocytic cell injury. Simultaneously, DTIO suppressed the production and release of inflammatory cytokines, and reduced the formation of glial scar. Homology modeling analysis illustrated that DTIO had an ability of binding to RIP1K. Furthermore, immunoprecipitation analysis showed that DTIO inhibited the phosphorylation of RIP1K and decreased the interaction between the RIP1K and RIP3K. In addition, knockdown of RIP1K had neuroprotective effects and inhibited the release of proinflammatory cytokines, but didn't have a significant effect on DTIO-mediated neuroprotection. In conclusion, DTIO has protective effects on acute ischemic stroke and promotes functional recovery during chronic phase, associating with protecting ischemic neurons and astrocytes, inhibiting inflammation, and lessening the glial scar formation via inhibiting of the RIP1K.

Radical alkylation of para-quinone methides with 4-substituted Hantzsch esters/nitriles via organic photoredox catalysis.

A novel photocatalytic protocol is herein described for the preparation of functionalized phenols via radical alkylation of para-quinone methides under transition-metal-free conditions. The reaction is external oxidant free and performed at ambient temperature upon visible light irradiation, allowing the access to various desired products in satisfactory yields. The readily available 4-alkyl-1,4-dihydropyridines serve as the effective alkyl radical precursors.

Photoredox-catalysed chloro-, bromo- and trifluoromethylthio-trifluoromethylation of unactivated alkenes with sodium triflinate.

A mild and transition-metal-free protocol is herein presented for chloro-, bromo- and trifluoromethylthiotrifluoromethylation of unactivated alkenes. The easy-handling Langlois reagent, as well as N-halophthalimide and N-trifluoromethylthiosaccharin, is used in this method. In the presence of an organic photoredox catalyst N-methyl-9-mesityl acridinium, a broad range of desired products were afforded in satisfactory yields upon visible-light irradiation via a radical process.

Discovery of novel curcumin derivatives targeting xanthine oxidase and urate transporter 1 as anti-hyperuricemic agents.

A series of curcumin derivatives as potent dual inhibitors of xanthine oxidase (XOD) and urate transporter 1 (URAT1) was discovered as anti-hyperuricemic agents. These compounds proved efficient effects on anti-hyperuricemic activity and uricosuric activity in vivo. More importantly, some of them exhibited proved efficient effects on inhibiting XOD activity and suppressing uptake of uric acid via URAT1 in vitro. Especially, the treatment of 4d was demonstrated to improve uric acid over-production and under-excretion in oxonate-induced hyperuricemic mice through regulating XOD activity and URAT1 expression. Docking study was performed to elucidate the potent XOD inhibition of 4d. Compound 4d may serve as a tool compound for further design of anti-hyperuricemic drugs targeting both XOD and URAT1.

Cathepsin B and L inhibitors: a patent review (2010 - present).

INTRODUCTION: Cathepsins play an important role in protein degradation and processing. Aberrant cathepsin B or L is closely associated with many serious diseases such as cancer, osteoporosis and autoimmune disorders. Therefore, development of potent and selective cathepsin B and L inhibitors has aroused much attention in recent years. Although several classes of cathepsin inhibitors are presently available, there are still some problems to solve, such as broad-spectrum inhibition to protease, specially cysteine proteases, which lead to unpredictable side effects in clinical trials. Therefore, it is very necessary to discovery new scaffolds and new application of cathepsin B and L inhibitors for developing therapeutic agents for treating diseases mediated by cathepsin B or L. Areas covered: This updated review summarizes new patents on cathepsin B and L inhibitors from 2010 to present. Expert opinion: The review gives the latest development in the area of inhibitors of cathepsin B and L, which have been considered key therapeutic targets for the development of drugs treating related diseases. This review puts emphasis on the discovery of novel small molecule inhibitors of cathepsin B and L, as well as their new application as new therapeutic agents.

Antioxidant properties and PC12 cell protective effects of a novel curcumin analogue (2E,6E)-2,6-bis(3,5- dimethoxybenzylidene)cyclohexanone (MCH).

The antioxidative properties of a novel curcumin analogue (2E,6E)-2,6-bis(3,5-dimethoxybenzylidene)cyclohexanone (MCH) were assessed by several in vitro models, including superoxide anion, hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and PC12 cell protection from H2O2 damage. MCH displayed superior O2•- quenching abilities compared to curcumin and vitamin C. In vitro stability of MCH was also improved compared with curcumin. Exposure of PC12 cells to 150 µM H2O2 caused a decrease of antioxidant enzyme activities, glutathione (GSH) loss, an increase in malondialdehyde (MDA) level, and leakage of lactate dehydrogenase (LDH), cell apoptosis and reduction in cell viability. Pretreatment of the cells with MCH at 0.63-5.00 µM before H2O2 exposure significantly attenuated those changes in a dose-dependent manner. MCH enhanced cellular expression of transcription factor NF-E2-related factor 2 (Nrf2) at the transcriptional level. Moreover, MCH could mitigate intracellular accumulation of reactive oxygen species (ROS), the loss of mitochondrial membrane potential (MMP), and the increase of cleaved caspase-3 activity induced by H2O2. These results show that MCH protects PC12 cells from H2O2 injury by modulating endogenous antioxidant enzymes, scavenging ROS, activating the Nrf2 cytoprotective pathway and prevention of apoptosis.

Growth inhibitory effect of KYKZL-1 on Hep G2 cells via inhibition of AA metabolites and caspase-3 pathway and cell cycle arrest.

KYKZL-1, a newly synthesized compound with COX/5-LOX dual inhibition, was subjected to the inhibitory activity test on Hep G2 growth. We found that KYKZL-1 inhibited the growth of Hep G2 cells via inducing apoptosis. Further studies showed that KYKZL-1 activated caspase-3 through cytochrome c release from mitochondria and down regulation of Bcl-2/Bax ratio and reduced the high level of COX-2 and 5-LOX. As shown in its anti-inflammatory effect, KYKZL-1 also exhibited inhibitory effect on the PGE2 and LTB4 production in Hep G2 cells. Accordingly, exogenous addition of PGE2 or LTB4 reversed the decreases in cell viability. In addition, KYKZL-1 caused cell cycle arrest at the S-G2 checkpoint via the activation of p21(CIP1) protein and down-regulation of cyclin A expression. These data indicate that the growth inhibitory effect of KYKZL-1 is associated with inhibition of AA metabolites and caspase-3 pathway and cell cycle arrest. Combined with our previous findings, KYKZL-1 exhibiting COX/5-LOX inhibition may be a promising potential agent not only for inflammation control but also for cancer prevention/therapy with an enhanced gastric safety profile.

Novel FabH inhibitors: an updated article literature review (July 2012 to June 2013).

INTRODUCTION: Fatty acid biosynthesis is essential for the bacterial viability and growth. In recent years, ß-ketoacyl-acyl carrier protein synthase III (FabH) become an attractive new target, which catalyzes the first step of fatty acid biosynthesis, and FabH inhibitors could be potential candidates for antibacterial agents. In this review, recent advances in the research of FabH inhibitors are reviewed. AREAS COVERED: This updated review summarized new patents and articles publications on FabH inhibitors within July 2012 to June 2013. EXPERT OPINION: The review gives the latest development in the area of FabH inhibitors which aim to solve the bacterial resistance. The potent antibacterial activities of the selected compounds are probably correlated to their FabH inhibitory. Molecular docking of the most potent compound in every kind of compounds against FabH was also reviewed to explore the binding mode of the compound at the active site.

Autophagy and cathepsin L are involved in the antinociceptive effect of DMBC in a mouse acetic acid-writhing model.

AIM: 2-(3',5'-Dimethoxybenzylidene) cyclopentanone (DMBC) is a novel synthetic compound with antinociceptive activities. The aim of this study was to investigate the roles of the autophagic-lysosomal pathway in the antinociceptive effect of DMBC in a mouse acetic acid-writhing model. METHODS: Mouse acetic acid-writhing test and hotplate test were used to assess the antinociceptive effects of DMBC, 3-MA (autophagy inhibitor) and Clik148 (cathepsin L inhibitor). The drugs were administered peripherally (ip) or centrally (icv). RESULTS: Peripheral administration of 3-MA (7.5-30 mg/kg) or Clik148 (10-80 mg/kg) produced potent antinociceptive effect in acetic acid-writhing test. Central administration of 3-MA or Clik148 (12.5-50 nmol/L) produced comparable antinociceptive effect in acetic acid-writhing test. Peripheral administration of DMBC (25-50 mg/kg) produced potent antinociceptive effects in both acetic acid-writhing and hotplate tests. Furthermore, the antinociceptive effect produced by peripheral administration of DMBC (50 mg/kg) in acetic acid-writhing test was antagonized by low doses of 3-MA (3.75 mg/kg) or Clik148 (20 mg/kg) peripherally administered, but was not affected by 3-MA or Clik148 (25 nmol/L) centrally administered. CONCLUSION: Activation of central autophagy and cathepsin L is involved in nociception in mice, whereas peripheral autophagy and cathepsin L contributes, at least in part, to the antinociceptive effect of DMBC in mice.

Inhibition of inflammatory mediators contributes to the anti-inflammatory activity of KYKZL-1 via MAPK and NF-κB pathway.

KYKZL-1, a newly synthesized compound with COX/5-LOX dual inhibition, was subjected to the anti-inflammatory activity test focusing on its modulation of inflammatory mediators as well as intracellular MAPK and NF-κB signaling pathways. In acute ear edema model, pretreatment with KYKZL-1 (p.o.) dose-dependently inhibited the xylene-induced ear edema in mice with a higher inhibition than diclofenac. In a three-day TPA-induced inflammation, KYKZL-1 also showed significant anti-inflammatory activity with inhibition ranging between 20% and 64%. In gastric lesion test, KYKZL-1 elicited markedly fewer stomach lesions with a low index of ulcer as compared to diclofenac in rats. In further studies, KYKZL-1 was found to significantly inhibit the production of NO, PGE2, LTB4 in LPS challenged RAW264.7, which is parallel to its attenuation of the expression of iNOS, COX-2, 5-LOX mRNAs or proteins and inhibition of phosphorylation of p38 and ERK MAPKs and activation of NF-κB. Taken together, our data indicate that KYKZL-1 comprises dual inhibition of COX and 5-LOX and exerts an obvious anti-inflammatory activity with an enhanced gastric safety profile via simultaneous inhibition of phosphorylation of p38 and ERK MAPKs and activation of NF-κB.

Design, synthesis and molecular docking of α,ß-unsaturated cyclohexanone analogous of curcumin as potent EGFR inhibitors with antiproliferative activity.

A type of novel α,ß-unsaturated cyclohexanone analogous, which designed based on the curcumin core structure, have been discovered as potential EGFR inhibitors. These compounds exhibit potent antiproliferative activity in two human tumor cell lines (Hep G2 and B16-F10). Among them, compounds I(3) and I(12) displayed the most potent EGFR inhibitory activity (IC(50) = 0.43 µM and 1.54 µM, respectively). Molecular docking of I(12) into EGFR TK active site was also performed. This inhibitor nicely fitting the active site might well explain its excellent inhibitory activity.

Biological evaluation of 2-(4-amino-phenyl)-3-(3,5-dihydroxylphenyl) propenoic acid.

2-(4-Aminophenyl)-3-(3,5-dihydroxylphenyl) propenoic acid (CSN-07001) is a new compound based on the combination of resveratrol and propenoic acid derivatives. In vitro cyclooxygenase (COX)/5-lipoxygenase (5-LOX) inhibition assays showed that the test compound exhibited a dual inhibitory activity against the COX (COX-1 IC(50) = 2.20 microM, COX-2 IC(50) = 1.76 microM) and 5-LOX (IC(50) = 0.28 microM) enzymes. Further, the enhanced COX-1/COX-2/5-LOX expression in lipopolysaccaride-induced lung inflammation in mice was also suppressed by CSN-07001 in a concentration-dependent manner. In vivo studies showed that CSN-07001 exhibited potent anti-inflammatory and antinociceptive effects in different experimental models. We further examined the risk of gastric damage induced by CSN-07001. The test compound was gastric-sparing in that it elicited markedly fewer stomach lesions than indomethacin in rats. Taken together, our data indicate that CSN-07001 exhibits a novel class of dual inhibitors of COX and 5-LOX having therapeutic potential as non-steroidal anti-inflammatory agents with an enhanced gastric safety profile.

Preventive effect of crocin in inflamed animals and in LPS-challenged RAW 264.7 cells.

Gardenia jasminoides Ellis and Crocus sativus L. are both traditional Chinese medicines that have significant biologic activities on inflammatory processes. But the active ingredients remain unclear. Crocin, a representative of carotenoid compounds, has now drawn considerable attention not only because it is a natural food colorant but also because it has great potential in medicine. But until now, the systematic anti-inflammatory effect of crocin has not been well established. In the present study, experiments were carried out to evaluate the anti-inflammatory effects of crocin in vitro and in vivo. In vitro, cyclooxygenase (COX) inhibition assays showed that crocin exhibits a dual inhibitory activity against the COX-1 and COX-2 enzymes. Anti-inflammatory activity in vivo was evaluated using two animal edema model tests. Pretreatment with crocin (p.o.) dose-dependently inhibited the xylene-induced ear edema in mice and carrageenan-induced paw edema in rats. In gastric lesion tests, crocin was gastric-sparing in that it elicited markedly fewer stomach lesions as compared to the number of stomach lesions caused by indomethacin in rats. In further studies, crocin was found to significantly inhibit the productions of prostaglandin E(2) (PGE(2)) in lipopolysaccharide (LPS)-challenged RAW 264.7, which is parallel to its prevention of the nuclear translocation of the NF-kappaB p50 and p65 subunits. These data indicate that crocin exhibits obvious anti-inflammatory effects and may be one of the active ingredients in Gardenia jasminoides Ellis or Crocus sativus L. that can modulate inflammatory processes.

Anti-inflammatory effects and gastrointestinal safety of NNU-hdpa, a novel dual COX/5-LOX inhibitor.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with a risk of serious adverse events. Now, the development of dual inhibitors of cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) has become a hot area in searching for safer NSAIDs. NNU-hdpa, 2-(4-hydroxylphenyl)-3-(3,5-dihydroxylphenyl) propenoic acid, a newly synthesized compound, is expected to have COX/5-LOX dual inhibition with an improved gastrointestinal profile. In this study, NNU-hdpa was subjected to in vitro and in vivo experiment protocols. In vitro COX/5-LOX inhibition assays showed that NNU-hdpa exhibits a dual inhibitory activity against the COX and 5-LOX enzymes. Anti-inflammatory activity in vivo was evaluated using two animal edema model tests. Pretreatment with NNU-hdpa (p.o.) dose-dependently inhibited the xylene-induced ear edema in mice and carrageenan-induced paw edema in rats respectively. In gastric lesion test, NNU-hdpa was gastric-sparing in that it elicited markedly fewer stomach lesions as compared to the stomach lesions caused by aspirin in rats. In further studies, NNU-hdpa was found to significantly inhibit the productions of PGE(2) and LTB(4) in LPS-challenged RAW 264.7, which is parallel to its prevention of the nuclear translocation of the NF-kappaB p50 and p65 subunits. These data indicate that NNU-hdpa comprises a novel class of dual inhibitors of COX and 5-LOX having therapeutic potential with an enhanced gastric safety profile.

[Synthesis and anti-inflammatory activity of p-(methanesulfonyl) styrene-linked cyclic ketone derivatives].

AIM: To search for new compounds with strong anti-inflammatory activity and low gastrointestinal (GI) side effects. METHODS: A series of p-(methanesulfonyl) styrene-linked cyclic ketone derivatives were synthesized. Their anti-inflammatory activities against xylene-induced mice ear swelling and carrageenan-induced rat paw edema were evaluated, and their GI side effects in the rats were examined. RESULTS: Nine target compounds (ZA(1-9)) were obtained, and their structures were determined by IR, 1HNMR, MS and elemental analysis. Compared with controls diclofenac (DC) and rofecoxib (RC) , ZA(3, 5-9) showed no significant difference in anti-inflammatory activity against xylene-induced ear swelling in mice. ZA(3, 7, 8) showed potency comparable to DC and RC (P > 0.05) and ZA6 was more potent than DC and RC (P < 0.05) in the treatment of carrageenan-induced rat paw edema. ZA(3, 5-9) showed less GI side effects than DC (P < 0.05, P < 0.01) and no significant difference compared with RC (P > 0.05). CONCLUSION: p-(Methanesulfonyl) styrene-linked cyclic ketone derivatives showed strong anti-inflammatory activity but few GI side effects and deserve to be further investigated.

[Synthesis and anti-inflammatory activity of alpha-substituted p-(methanesulfonyl)phenylpropenamides].

AIM: To search for new compounds with strong anti-inflammatory activity and low gastrointestinal (GI) side effects. METHODS: A series of alpha-substituted p-(methanesulfonyl) phenyl-propenamides were synthesized. Their anti-inflammatory activities against xylene-induced mice ear swelling and carrageenan-induced rat paw edema were evaluated, and their GI side effects in rats were examined. RESULTS: Twenty-five target compounds (II1-25) were obtained, and their structures were determined by IR, 1H NMR, MS and elemental analysis. Thirteen compounds (II1,3,5,8-13,15,18,19,23) exhibited marked anti-inflammatory activity comparable to diclofenac sodium (DC) and rofecoxib (RC) in xylene-induced mice ear swelling model, and twelve compounds (II1,3,5,7,8,10-12,17,18,20,23) showed remarkable anti-inflammatory activity comparable to DC and RC in carrageenan-induced rat paw edema. Compounds II3,8,10,11,18,20 showed GI side effects less than DC (P < 0.01), and no significant difference compared with RC and CMC-Na (P > 0.05). CONCLUSION: alpha-Substituted p-(methanesulfonyl)phenylpropenamides showed strong anti-inflammatory activity but few GI side effects and deserve to be further investigated.