Design and synthesis of urea and thiourea derivatives and their inhibitory activities on lipopolysaccharide-induced NO production

Series of ureas and thioureas were designed and synthesized, and their inhibitory activities of NO production in lipopolysaccharide-activated macrophages were evaluated. We found several essential moieties in the structure of the prepared compounds for the activity. Thiourea derivatives revealed higher inhibitory activity than the corresponding urea derivatives. Among these compounds, 7e having carboxymethyl group at N3 position of thiourea was the most potent in the inhibition of NO production. They inhibited NO production through the suppression of iNOS protein and mRNA expression.     

Synthesis of novel derivatives of esculentoside A and its aglycone phytolaccagenin, and evaluation of their haemolytic activity and inhibition of lipopolysaccharide-induced nitric oxide production

A series of 46 compounds derived from esculentoside A and its aglycone were synthesized and characterized. The effect of these compounds on lipopolysaccharide (LPS)-induced NO production, haemolytic activity, and cell viability was evaluated. Structure-activity relationship was established by comparing the derivatives of esculentoside A with its aglycone derivatives. Both the aglycone and its derivatives showed higher inhibitory effects on LPS-induced NO production, and lower haemolytic activities than esculentoside A and its derivatives.     

Novel cyclohexene derivatives as anti-sepsis agents: synthetic studies and inhibition of NO and cytokine production

In order to develop an anti-sepsis agent, a series of cyclohexene derivatives were synthesized and evaluated for their biological activities. Through modification of the sulfonamide spacer moiety depicted by formula II, it was found that the benzylsulfone derivative 10a had potent inhibitory activity against the production of NO. Further modifications of the phenyl ring, ester moiety, and benzyl position of benzylsulfone derivatives III were carried out. Among these compounds, (R)-(+)-10a and (6R, 1S)-(+)-22a showed strong inhibitory activity not only against NO production but also against inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in vitro. Furthermore, (R)-(+)-10a and (6R, 1S)-(+)-22a protected mice from LPS-induced lethality in a dose-dependent manner.     

Effects of resveratrol and its derivatives on lipopolysaccharide-induced microglial activation and their structure-activity relationships

The inhibitory effects of 21 resveratrol derivatives on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in microglia and their structure-activity relationships were studied. It was found, for the first time, that certain resveratrol derivatives that have 3,5-dimethoxyl groups in the A-ring, such as (E)-4-(3,5-dimethoxystyryl)phenol (pterostilbene, compound 2), or have substituted the B-ring of resveratrol with quinolyl, such as (E)-5-[2-(quinolin-4-yl)vinyl]benzene-1,3-diol (compound 18) and (E)-4-(3,5-dimethoxystyryl)quinoline (compound 19), strongly inhibited NO production. Compounds 2, 18, and 19 reduced LPS-induced protein and mRNA expression of inducible NO synthase (iNOS), but did not display direct NO-scavenging activity up to 30 microM in sodium nitroprusside (SNP) solution. Moreover, compounds 2, 18, and 19 could also significantly inhibit the production of TNF-alpha by LPS-activated microglia. Further studies revealed that compounds 2, 18, and 19 inhibited LPS-induced NO and TNF-alpha production in microglia by blocking IkappaBalpha phosphorylation and degradation. The potent inhibitory effects of compounds 2, 18, and 19 on microglial activation suggest their potential for treatment of neurodegenerative diseases accompanied by microglial activation.     

Identification and structure activity relationship of novel flavone derivatives that inhibit the production of nitric oxide and PGE2 in LPS-induced RAW 264.7 cells

In an effort to identify novel anti-inflammatory compounds, a series of flavone derivatives were synthesized and biologically evaluated for their inhibitory effects on the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂), representative pro-inflammatory mediators, in LPS-induced RAW 264.7 cells. Their structure-activity relationship was also investigated. In particular, we found that compound 3g displayed more potent inhibitory activities on PGE₂ production, similar inhibitory activities on NO production and less weak cytotoxicity than luteolin, a natural flavone known as a potent anti-inflammatory agent.     

Inhibitory effects of phloroglucinol derivatives from Mallotus japonicus on nitric oxide production by a murine macrophage-like cell line, RAW 264.7, activated by lipopolysaccharide and interferon-gamma.

An aqueous acetone extract of the pericarps of Mallotus japonicus (MJE) inhibited nitric oxide (NO) production by a murine macrophage-like cell line, RAW 264.7, which was activated by lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Seven phloroglucinol derivatives isolated from MJE exhibited inhibitory activity against NO production. Among these phloroglucinol derivatives, isomallotochromanol exhibited strong inhibitory activity toward NO production, exhibiting an IC(50) of 10.7 microM. MJE and the phloroglucinol derivatives significantly reduced both the induction of inducible nitric oxide synthase (iNOS) protein and iNOS mRNA expression. NO production by macrophages preactivated with LPS and IFN-gamma for 16 h was also inhibited by MJE and the phloroglucinol derivatives. Furthermore, MJE and the derivatives directly affected the conversion of L-[(14)C]arginine to L-[(14)C]citrulline by the cell extract. These results suggest that MJE and the phloroglucinol derivatives have the pharmacological ability to suppress NO production by activated macrophages. They inhibited NO production by two mechanisms: reduction of iNOS protein induction and inhibition of enzyme activity.     

Syntheses of NAMDA derivatives inhibiting NO production in BV-2 cells stimulated with lipopolysaccharide

Sixteen derivatives of N-acetyl-3-O-methyldopamine (NAMDA), an inhibitor of BH4 synthesis, were designed and synthesized. The ability of these derivatives to inhibit NO and BH4 production by lipopolysaccharide-stimulated BV-2 microglial cells was determined. While NAMDA at 100 microM inhibited NO and BH4 production by only about 20%, its catecholamide 8, indole 23 derivative, 13, and N-acetyl tetrahydroisoquinoline 25 inhibited the NO production by >50% at the same concentration. In particular, 13 and 25 inhibited both NO and BH4 production to similar degrees, which suggested that these compounds might inhibit NO production by blocking BH4-dependent dimerization of the newly synthesized iNOS monomer.     

Synthesis, in vitro anti-inflammatory and cytotoxic evaluation, and mechanism of action studies of 1-benzoyl-β-carboline and 1-benzoyl-3-carboxy-β-carboline derivatives

In the present study, various 1-substituted and 1,3-disubstituted β-carboline derivatives were synthesized by a modified single-step Pictet-Spengler reaction. The compounds were examined for cytotoxicity and anti-inflammatory activity, as measured by the inhibition of prostaglandin E(2) (PGE(2)) production and nitric oxide (NO) production. While only two compounds (28 and 31) showed marginal cytotoxicity against four human cancer cell lines, most of the tested compounds exhibited potent inhibitory activity of both NO and PGE(2) production. Moreover, compounds 6 and 16 significantly reduced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2), suggesting that β-carboline analogs can inhibit NO and PGE(2) production at the translational level. In addition, several of the β-carboline derivatives (1, 2, 4-8, 11, 13, 22, 25, 27, 31, and 41-43) displayed significant inhibitory activity of superoxide anion (O(2)(·-)) generation or elastase release compared to the reference compound, with 6 being the most potent. N-Formyl-L-methionyl-phenylalanine (FMLP)-induced phosphorylation of c-JunN-terminal kinase (JNK) and protein kinase B (AKT) were also inhibited by 6, suggesting that it suppresses human neutrophil functions by inhibiting the activation of JNK and AKT signaling pathways. Therefore, the synthetic 1-benzoyl-3-carboxy β-carboline analogs may have great potential to be developed as anti-inflammatory agents.     

Inhibitory effects of phloroglucinol derivatives from Mallotus japonicus on nitric oxide production by a murine macrophage-like cell line,RAW 264.7, activated by lipopolysaccharide and interferon-γ

An aqueous acetone extract of the pericarps of Mallotus japonicus (MJE) inhibited nitric oxide (NO) production by a murine macrophage-like cell line, RAW 264.7, which was activated by lipopolysaccharide (LPS) and interferon-γ (IFN-γ). Seven phloroglucinol derivatives isolated from MJE exhibited inhibitory activity against NO production. Among these phloroglucinol derivatives, isomallotochromanol exhibited strong inhibitory activity toward NO production, exhibiting an IC₅₀ of 10.7 μM. MJE and the phloroglucinol derivatives significantly reduced both the induction of inducible nitric oxide synthase (iNOS) protein and iNOS mRNA expression. NO production by macrophages preactivated with LPS and IFN-γ for 16 h was also inhibited by MJE and the phloroglucinol derivatives. Furthermore, MJE and the derivatives directly affected the conversion of L-[¹⁴C]arginine to L-[¹⁴C]citrulline by the cell extract. These results suggest that MJE and the phloroglucinol derivatives have the pharmacological ability to suppress NO production by activated macrophages. They inhibited NO production by two mechanisms: reduction of iNOS protein induction and inhibition of enzyme activity.     

Phenylsulphonyl urenyl chalcone derivatives as dual inhibitors of cyclo-oxygenase-2 and 5-lipoxygenase

Two series of phenylsulphonyl urenyl chalcone derivatives (UCH) with various patterns of substitution were tested for their effects on nitric oxide (NO) and prostaglandin E2 (PGE2) overproduction in RAW 264.7 macrophages. None of the tested compounds reduced NO production more than 50% at 10 microM but most of them inhibited the generation of PGE2 with IC50 values under the micromolar range. Me-UCH 1, Me-UCH 5, Me-UCH 9, Cl-UCH 1, and Cl-UCH 9 were selected to evaluate their influence on human leukocyte functions and eicosanoids generation. These derivatives selectively inhibited cyclo-oxygenase-2 (COX-2) activity in human monocytes being Me-UCH 5 the most potent (IC50 0.06 microM). Selected compounds also reduced leukotriene B4 synthesis in human neutrophils by a direct inhibition of 5-lipoxygenase (5-LO) activity, with IC50 values from 0.5 to 0.8 microM. In addition, lysosomal enzyme secretion, such as elastase or myeloperoxidase as well as superoxide generation in human neutrophils were also reduced in a similar range. Our findings indicate that UCH derivatives exert a dual inhibitory effect on COX-2/5-LO activity. The profile and potency of these compounds may have relevance for the modulation of the inflammatory and nociceptive responses with reduction of undesirable side-effects associated with NSAIDs.     

Anti-inflammatory isoflavones and isoflavanones from the roots of Pongamia pinnata (L.) Pierre

A phytochemical study on the roots of Pongamia pinnata afforded five new isoflavone and isoflavanone derivatives (1–5), including two previously undescribed phenylisoflavones possessing an 1,2-oxetane ring, along with 21 known compounds (6–26) among which compound 18 is the first time to be isolated from nature. The structures of the isolated compounds were determined on the basis of 1D, 2D NMR, and HRESIMS. The absolute configurations of the compounds were assigned via analysis of the specific rotations and circular dichroism (CD) spectra, as well as by comparison of the calculated and experimental electronic circular dichroism (ECD) data. All the isolated compounds were evaluated for their inhibitory effects on NO production in LPS-stimulated BV-2 microglial cells. Twelve compounds exhibited different levels of inhibitory effects against NO production, and compound 1 showed the best activity with an IC₅₀ value at 9.0?μM.     

Synthesis and biological evaluation of unique stereodimers of sinomenine analogues as potential inhibitors of NO production

Inhibition of the excessive NO production has been recognized as a potential means for the treatment of rheumatoid arthritis (RA). In order to discover more potent inhibitors and explore the preliminary structure activity relationship, a series of unique stereodimers of sinomenine analogues were designed and synthesized. Their inhibitory activity on NO production and cytotoxicity were evaluated using LPS-activated murine macrophages RAW264.7 assay and MTT method, respectively. Among these compounds, 1a, 2, 2a, 2b, and 4 showed potent inhibitory activity on NO production without obvious cytotoxicity. Furthermore, 2, 2a, and 2b significantly suppressed mRNA expression of iNOS. Interestingly, (S)-dimers displayed a better bioactivity than (R)-dimers. These compounds may sever as lead candidates in the development of novel therapeutic drugs for RA treatment.     

Synthesis,nitric oxide release,and α-glucosidase inhibition of nitric oxide donating apigenin and chrysin derivatives

α-Glucosidase (AG) play crucial roles in the digestion of carbohydrates. Inhibitors of α-glucosidase (AGIs) are promising candidates for the development of anti-diabetic drugs. Here, five series of apigenin and chrysin nitric oxide (NO)-donating derivatives were synthesised and evaluated for their AG inhibitory activity and NO releasing capacity in vitro. Except for 9a–c, twelve compounds showed remarkable inhibitory activity against α-glucosidase, with potency being better than that of acarbose and 1-deoxynojirimycin. All organic nitrate derivatives released low concentrations of NO in the presence of l-cysteine. Structure activity relationship studies indicated that 5-OH, hydrophobic coupling chain, and carbonyl groups of the coupling chain could enhance the inhibitory activity. Apigenin and chrysin derivatives therefore represents a new class of promising compounds that can inhibit α-glucosidase activity and supply moderate NO for preventing the development of diabetic complications.     

Synthesis and bioactivities of novel pyridazine derivatives: inhibitors of interleukin-1 beta (IL-1beta) production

New pyridazine derivatives were prepared, and their abilities to inhibit IL-1beta production were evaluated. Some compounds showed potent inhibitory activity against IL-1beta production in HL-60 cells stimulated with lipopolysaccharide (LPS). The synthesis and structure-activity relationships of these compounds are described.     

Structure-activity relationship studies on chalcone derivatives. the potent inhibition of chemical mediators release

Some chalcones exert potent anti-inflammatory activities. 2',5'-Dialkoxychalcones and 2',5'-dihydroxy-4-chloro-dihydrochalcone inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma)-activated N9 microglial cells and in LPS-activated RAW 264.7 macrophage-like cells have been demonstrated in our previous reports. These compounds also suppressed the inducible NO synthase (iNOS) expression and cyclooxygenase-2 (COX-2) activity in RAW 264.7 cells. In an effort to continually develop potent anti-inflammatory agent, a series of chalcones were prepared by Claisen-Schmidt condensation of appropriate acetophenones with appropriate aromatic aldehyde and then evaluated their inhibitory effects on the activation of mast cells, neutrophils, macrophages, and microglial cells. Most of the 2',5'-dihydroxychaclone derivatives exhibited potent inhibitory effects on the release of beta-glucuronidase and lysozyme from rat neutrophils stimulated with formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB). Some chalcones showed potent inhibitory effects on superoxide anion generation in rat neutrophils in response to fMLP/CB. Compounds 1 and 5 exhibited potent inhibitory effects on NO production in macrophages and microglial cells. Compound 11 showed inhibitory effect on NO production and iNOS protein expression in RAW 264.7 cells. The present results demonstrated that most of the 2',5'-dihydroxychaclones have anti-inflammatory effects. The potent inhibitory effect of 2',5'-dihydroxy-dihydrochaclones on NO production in LPS-activated macrophage, probably through the suppression of iNOS protein expression, is proposed to be useful for the relief of septic shock.     

Furoxan nitric oxide donor coupled chrysin derivatives: synthesis and vasculoprotection

A series of furoxan-based nitric oxide-releasing chrysin derivatives were synthesized. Pharmacological assays indicated that all chrysin derivatives exhibited in vitro inhibitory activities against aldose reductase and advanced glycation end-product formation. Some chrysin derivatives were also found to increase the glucose consumption of HepG2 cells. Furthermore, the compounds released a low amount of NO in the presence of l-cysteine (range from 0.20% to 1.89%). These hybrid furoxan-based NO donor chrysin derivatives offer a mutual prodrug design concept for the development of therapeutic or preventive agents for vascular complications due to diabetes.     

Effect of a combination of deoxynivalenol and nivalenol on lipopolisaccharide-induced nitric oxide production by mouse macrophages

Deoxynivalenol (DON) and nivalenol (NIV) are trichothecene mycotoxins produced by Fusarium fungi as secondary metabolites. Both compounds have the immunotoxic effects that the productions of inflammatory mediators by activated macrophages is disturbed. Co-contamination with DON and NIV can occur; however, the effects of simultaneous contamination are not well known. The present study investigated the combined effects of DON and NIV on nitric oxide (NO) production by mouse macrophages stimulated with lipopolisaccharide (LPS). The inhibitory effect of DON and NIV on NO release from activated macrophages has already been reported as an appropriate indicator of immunotoxic effect of the both compounds. LPS-induced NO production in macrophages was inhibited by both of these toxins individually in a dose-dependent manner, and toxin mixtures at the same concentration inhibited NO production in the same manner. In addition, there were no unique inhibitory effects on LPS-induced NO production in macrophages in the presence of mixtures of various molar ratios. These results suggest that the combined effects of DON and NIV can be predicted based on addition of each compound alone.     

Synthesis and bioactivities of novel piperidylpyrimidine derivatives: inhibitors of tumor necrosis factor-alpha production

New piperidylpyrimidine derivatives, including quinazolines, were prepared, and their abilities to inhibit TNF-alpha production evaluated. Some compounds showed potent inhibitory activity in mouse macrophages stimulated with LPS. The synthesis and structure activity relationships of these compounds are described.     

Five New Triene Derivatives from the Fungus Penicillium herquei JX4

Five undescribed triene derivatives, pinophols B–F ( 2 – 6 ), together with one known compound, pinophol A ( 1 ), were obtained from the mangrove endophytic fungus Penicillium herquei JX4. The structures of compounds 1 – 6 were elucidated using IR, HR-ESI-MS, and NMR methods. The absolute configurations of compounds 1 – 6 were confirmed by comparing their experimental or calculated ECD spectra. Pinophols C and D ( 3 and 4 ) showed inhibitory activities against LPS-induced NO production.