New jasmonate analogues as potential anti-inflammatory agents

In an effort to develop new anti-inflammatory agents, methyl jasmonate analogues (2-20) were synthesized and evaluated for their inhibitory effects on the production of pro-inflammatory mediators (NO, IL-6, and TNF-alpha) in lipopolysaccharide (LPS)-activated RAW264.7 murine macrophage cells. The introduction of an enone functionality to the structure of a plant hormone (1) rendered the product (2) a significant anti-inflammatory activity. Analogues further derived from 2 (7, 9, 13, and 15) exhibited even more enhanced activity, and these compounds were much more potent than natural anti-inflammatory prostaglandins (PGA(1), PGA(2), and 15-deoxy-Delta(12,14)-PGJ(2)). Among them, compounds 9 and 15 showed the highest potency, while compounds 7 and 13 would be more desirable with respect to safety. This is the first study demonstrating the anti-inflammatory potential of jasmonate derivatives, and the present results suggest that alpha-haloenone jasmonates (7, 9, 13, and 15) may serve as potential anti-inflammatory leads.     

Discovery of talmapimod analogues as polypharmacological anti-inflammatory agents

Abstract

Twenty novel talmapimod analogues were designed, synthesised and evaluated for the in vivo anti-inflammatory activities. Among them, compound 6n, the most potent one, was selected for exploring the mechanisms underlying its anti-inflammatory efficacy. In RAW264.7 cells, it effectively suppressed lipopolysaccharides-induced (LPS-induced) expressions of iNOS and COX-2. As illustrated by the western blot analysis, 6n downregulated both the NF-κB signalling and p38 MAPK phosphorylation. Further enzymatic assay identified 6n as a potent inhibitor against both p38α MAPK (IC₅₀=1.95?µM) and COX-2 (IC₅₀=0.036?µM). By virtue of the concomitant inhibition of p38α MAPK, its upstream effector, and COX-2, along with its capability to downregulate NF-κB and MAPK-signalling pathways, 6n, a polypharmacological anti-inflammatory agent, deserves further development as a novel anti-inflammatory drug.     

Coumarin Schiff-bases: as antioxidant and possibly anti-inflammatory agents

Coumarin Schiff-bases (CSB) possessing different substituents on the 4-methyl-2-substituted phenyl imino-2H-chromene-7-ol molecule were evaluated for their in-vitro antioxidant and plausible anti-inflammatory potential. The antioxidant studies of selected CSB were carried out by determining their reducing power, OH* radical scavenging activity, scavenging of stable 2,2-diphenyl-l-picrylhydrazine (DPPH*) radical and inhibition of the polyphenol oxidase (PPO) enzyme. The assessment of possible anti-inflammatory potential was performed by trypsin inhibition assay and inhibition of beta-glucuronidase. All the CSBs under study showed significant reducing effects. The majority of the tested CSB were found to be effective scavengers of DPPH* radical with moderate to low OH* scavenging ability and significantly inhibited the activity of PPO. With few exceptions, results from the inhibition assay of trypsin and beta-glucuronidase were not encouraging, however they may be helpful in defining structure-activity relationships in further optimization of the lead molecules.     

Inhibition of the mono-oxygenase system by butylated hydroxyanisole and butylated hydroxytoluene

The commonly used food-additive antioxidants, butylated hydroxyanisole and butylated hydroxytoluene, are inhibitors of the hepatic microsomal mono-oxygenase system, as assayed by benzpyrene hydroxylase activity and demethylase activities. Generally, butylated hydroxyanisole is a more potent inhibitor than butylated hydroxytoluene. Both inhibitors bind to cytochrome P-450 and induce “type I” binding spectra. Cytochrome P-450 is tentatively assigned as the site of inhibition.     

Design, synthesis, biological evaluation and molecular docking of curcumin analogues as antioxidant, cyclooxygenase inhibitory and anti-inflammatory agents

Curcuminoids were isolated from Curcuma longa and their pyrazole and isoxazole analogues were synthesized and evaluated for antioxidant, COX-1/COX-2 inhibitory and anti-inflammatory activities. The designed analogues significantly enhance COX-2/COX-1 selectivity and possess significant anti-inflammatory activity in carrageenan induced rat paw edema assay. Pyrazole, isoxazole analogues of curcumin (4 and 7) exhibited higher antioxidant activity than trolox. Molecular docking study revealed the binding orientations of curcumin analogues in the active sites of COX and thereby helps to design novel potent inhibitors.     

Freezing dog semen in presence of the antioxidant butylated hydroxytoluene improves postthaw sperm membrane integrity

In an attempt to evaluate the protective effect of a lipid-soluble antioxidant (butylated hydroxytoluene; BHT), semen from four dogs (Canis familiaris) was frozen in two different extenders (Uppsala or INRA-96 plus glycerol) with or without 1 mM BHT. Sperm membrane integrity using flow cytometry and motility using a computerized system were evaluated in each experimental group. The Uppsala extender was superior in all aspects of sperm function. The percentage of sperm membranes was significantly higher in semen samples frozen in presence of BHT. Our results suggest that the Uppsala extender can be improved with the addition of BHT.     

Synthesis and biological evaluation of novel heteroring-annulated pyrrolino-tetrahydroberberine analogues as antioxidant agents

Tetrahydroberberine (THB), otherwise known as canadine, is a natural alkaloid showing significant pharmacological properties and antioxidant protection against oxidative damage. Herein, we synthetized structurally complex THB analogues, namely pyrrolino-tetrahydroberberines (PTHBs) 4a–g, containing the pyrrolino[2,3-b]pyridine system, by means of the reactions of 1,2-diaza-1,3-dienes and 7,8-dihydroberberine. Aim of the study was to explore the in vitro antioxidant properties of PTHBs in comparison to THB thus to identify the most effective against free radical-induced oxidative injury, by using three different antioxidant tests: the ORAC method, the DNA nicking assay, and the DCFH-DA cellular assay. As a result, PTHB 4d emerged among the other THB analogues by exhibiting the best antioxidant properties. First, it was the only compound having an ORAC value completely comparable to that of THB, indicating the same ability to neutralize peroxyl radicals. Secondly, 4d showed an even better antioxidant capacity than THB in protecting DNA against ferrous ion-induced strand breaks. These observations were also confirmed in NCTC-2544 human keratinocytes exposed to hydrogen peroxide. Indeed, 4d protected cells against oxidation more efficiently than THB both in the short (1 and 3?h) and long (24?h) period of incubation, possibly suggesting increased cell membrane permeability and/or intracellular stability of 4d as compared to THB.     

New anti-inflammatory agents

The pyrrole derivatives la, b and 2a, b were used as precursors for the preparation of N-substituted pyrrole derivatives 3a, b-9a, b and pyrrolo[2,3-d]pyrimidines 13-16. Also, all the newly prepared products were tested for anti-inflammatory activity as analogues to fenamates, and some of them revealed moderate anti-inflammatory activity compared to the standard drug indomethacin.     

Synthesis and biological evaluation of nitrogen-containing chalcones as possible anti-inflammatory and antioxidant agents

A novel series of nitrogen-containing chalcones were synthesized by Mannich reaction and were screened for anti-inflammatory related activities such as inhibition of cyclooxygenase-2 (COX-2), trypsin and β-glucuronidase. The antioxidant potential was demonstrated using 1,1-diphenyl-2-picryl hydrazine (DPPH) radical scavenging activity. The results of the above studies shows that the compounds synthesized were found to be effective inhibitors of above pro-inflammatory enzymes, and were found to be possess moderate radical scavenging potential. Overall, the results of the studies reveal that the chalcones with N-methyl piperazine methyl and piperidine methyl substitution (4c, 3b, 4d, 6b) seems to be important for inhibition of β-glucuronidase. Whereas the chalcones with piperidine methyl substitution (8b, 7b, 7c, 6c, 4b, 3c, 3b) were observed as effective inhibitors of COX-2, while the same compounds were found to be less reactive against COX-1 as compared to COX-2.     

The antioxidant butylated hydroxytoluene stimulates platelet protein kinase C and inhibits subsequent protein phosphorylation induced by thrombin

The phenolic antioxidant 2,6-bis(1,1-dimethyl ethyl)-4-methylphenol (BHT) evokes a transient phosphorylation of two platelet proteins of Mr 20,000 and 47,000 that are well-known substrates of protein kinase C (PKC) and, similarly to phorbol esters, a slight but persistent phosphorylation of a protein of Mr 26,000. These effects are observed both in the presence and in the absence of extracellular calcium, but are abolished in the presence of the protein kinase C inhibitor staurosporine. The phosphorylation of the 47 kDa protein takes place mostly at the serine and, to a lesser extent, at threonine residues. BHT induces an increased binding of tritiated phorbol dibutyrate to platelets indicating a PKC translocation from cytosol to plasma membrane. Addition of BHT (20 microM) a few min prior to thrombin causes inhibition of both agonist-evoked protein phosphorylation and increase in the Ca2+ concentration, the latter inhibition being counteracted by staurosporine. The inhibitory effect lasts for several minutes even after removal of BHT from the cellular suspending medium. Similar results are obtained with nordihydroguaiaretic acid, whereas 2- and 3-tert-butyl-4-methoxyphenol (BHA) produce only slight effects. BHT activates the protein kinase C purified from pig brain in a concentration-dependent manner (up to 200 microM), whereas it does not affect the activity of other purified protein kinases such as type 1 and 2 casein kinases, type II A, II B and III tyrosine protein kinases from rat spleen and the catalytic subunit of cyclic AMP-dependent protein kinase. It is concluded that, similarly to diacylglycerols and phorbol esters, these phenolic antioxidants activate the protein kinase C, which in turn desensitizes platelets towards subsequent phospholipase C activation.     

Design,synthesis and pharmacological evaluation of novel tetrasubstituted thiophene analogues as anti-inflammatory agents

A new series of tetrasubstituted thiophene analogues (4a-4f, 5a-5f and 8a-8i) were designed incorporating the pharmacophoric features of COX-1 (as in fenamates), 5-LOX and the p38 MAP kinase inhibitors. The designed series was synthesized by nucleophilic addition of aryl/aroylisothiocyanate and enamine (2) yielding the addition product l-(α-Carbomethoxy-β-aminothiocrotonoyl)-aryl/aroyl amines (3/7); which on reaction with substituted phenacyl bromides gave the targeted tetrasubstituted thiophene esters (4a-4f / 8a-8i). The tetrasubstituted thiophenes esters (4a-4f ) on hydrolysis with one equivalent of potassium hydroxide solution in methanol at room temperature gave corresponding acids (5a-5f ). All the targeted compounds were evaluated for their anti-inflammatory activity in carrageenin-induced rat hind paw oedema model at the doses of 10, 20 and 40 mg/kg body weight using standard drugs mefanamic acid and ibuprofen. The compounds (4c, 4e, 4f, 5f, 8a- 8i) which gave reasonable protection to the inflamed paw, eliciting good or moderate comparable anti-inflammatory activity were selected for investigating their analgesic activity using acetic acid induced writhing response test in albino mice at 10 mg/kg dose using standard drug ibuprofen and in order to arrive at possible mechanism of their anti-inflammatory activity, in vitro antioxidant nitric oxide radical scavenging assay at the concentrations of 5, 10, 15, 20, 25, 30 and 35 μg/mL were performed using standard drug ascorbic acid.     

A reappraisal of the proposed metabolic and antioxidant actions of butylated hydroxytoluene (BHT) in the liver

Butylated hydroxytoluene (BHT) was investigated for its metabolic actions in the perfused rat liver. Contrary to what is expected from an uncoupler, BHT up to 500 μM did not stimulate oxygen uptake nor did it inhibit gluconeogenesis from lactate. Transformation of fructose into glucose was also not affected by BHT; only lactate production was slightly increased at the concentration of 100 μM. The uncoupling effect of BHT in isolated mitochondria was confirmed, but only at concentrations above 10 μM; uncoupling at lower concentrations, 10^?9 to 10^?6 M, could not be confirmed. BHT, however, increased reactive oxygen species (ROS) production in isolated mitochondria, starting at the concentration of 10^?8 M. This is the opposite of what can be expected from a compound with proven ex vivo antioxidant action. One cannot exclude the possibility that, in mitochondria, stimulation of ROS production rather than uncoupling could be the most significant effect of BHT.     

Design, synthesis and pharmacological evaluation of novel tetrasubstituted thiophene analogues as anti-inflammatory agents

A new series of tetrasubstituted thiophene analogues (4a-4f, 5a-5f and 8a-8i) were designed incorporating the pharmacophoric features of COX-1 (as in fenamates), 5-LOX and the p38 MAP kinase inhibitors. The designed series was synthesized by nucleophilic addition of aryl/aroylisothiocyanate and enamine (2) yielding the addition product l-(alpha-Carbomethoxy-beta-aminothiocrotonoyl)-aryl/aroyl amines (3/7); which on reaction with substituted phenacyl bromides gave the targeted tetrasubstituted thiophene esters (4a-4f / 8a-8i). The tetrasubstituted thiophenes esters (4a-4f ) on hydrolysis with one equivalent of potassium hydroxide solution in methanol at room temperature gave corresponding acids (5a-5f ). All the targeted compounds were evaluated for their anti-inflammatory activity in carrageenin-induced rat hind paw oedema model at the doses of 10, 20 and 40 mg/kg body weight using standard drugs mefanamic acid and ibuprofen. The compounds (4c, 4e, 4f, 5f, 8a- 8i) which gave reasonable protection to the inflamed paw, eliciting good or moderate comparable anti-inflammatory activity were selected for investigating their analgesic activity using acetic acid induced writhing response test in albino mice at 10 mg/kg dose using standard drug ibuprofen and in order to arrive at possible mechanism of their anti-inflammatory activity, in vitro antioxidant nitric oxide radical scavenging assay at the concentrations of 5, 10, 15, 20, 25, 30 and 35 microg/mL were performed using standard drug ascorbic acid.     

Synthesis of some newer analogues of substituted dibenzoyl phenol as potent anti-inflammatory agents

Benzoylation of hydroxybenzophenones 1a-f affords substituted benzoyl phenyl benzoates 3a-f, which on Fries rearrangement using microwave irradiation led to a facile synthesis of solely dibenzoyl phenols 4a-f in excellent yield. The newly synthesized compounds were screened for their anti-inflammatory activity and were compared with standard drugs. Out of the compounds studied, the compound 4e showed more potent activity than the standard drugs at all doses tested.     

Nimesulide analogues: From anti-inflammatory to antitumor agents

Nimesulide is a nonsteroidal anti-inflammatory drug possessing analgesic and antipyretic properties. This drug is considered a selective cyclooxygenase-2 (COX-2) inhibitor and, more recently, has been associated to antitumor activity. Thus, numerous works have been developed to modify the nimesulide skeleton aiming to develop new and more potent and selective COX-2 inhibitors as well as potential anticancer agents. This review intends to provide an overview on analogues of nimesulide, including the general synthetic approaches used for their preparation and structural diversification and their main anti-inflammatory and/or antitumor properties.     

Biological evaluation of several coumarin derivatives designed as possible anti-inflammatory/antioxidant agents

Several linear and angular coumarins designed and synthesised as possible anti-inflammatory and antioxidant agents were evaluated for their biological activities, using the carrageenin-induced rat paw oedema model. In general, the compounds were found to be potent anti-inflammatory agents. Compound (4) was found to possess protective properties in adjuvant-induced arthritis in rats. The compounds were found to interact with 1,1-diphenyl-2-picryl-hydrazyl stable free radical (DPPH) whereas most of them were essentially inactive in other tests. The anti-inflammatory activity seemed to be connected with their reducing activity. R(M) values were determined as an expression of their lipophilicity which was also calculated as clog P. Only a poor relationship existed between lipophilicity and anti-inflammatory activity.     

New 3- and 4-hydroxyfuranones as anti-oxidants and anti-inflammatory agents

Two series of new furanones substituted by methylsulfonylphenyl or methylsulfamidophenyl moieties were found to protect against oxidation damage by inhibiting or quenching free radicals and reactive oxygen species in in vitro experiments. The effect on lipid peroxidation was also examined. In addition, we investigated the activity of products in two models of inflammation: phorbol ester-induced ear edema in mice and carrageenan-induced paw edema in rat. The most powerful compounds and with reducing activity against DPPH (IC50=1779 and 57 microM, respectively), superoxide anion quenching capacity (IC50=511 and 49 microM, respectively), lipid peroxidation inhibitory effect and anti-inflammatory properties (about 50-65% inhibition of edema at 200 mg/kg ip in both tests used) were selected for further pharmacological and toxicological tests because of their attractive profile for the treatment of inflammatory diseases.     

Synthesis and biological evaluation of simple methoxylated chalcones as anticancer,anti-inflammatory and antioxidant agents

Chalcones have been identified as interesting compounds with cytotoxicity, anti-inflammatory and antioxidant properties. In the present study, simple methoxychalcones were synthesized by Claisen–Schmidt condensation reaction and evaluated for above biological activities. The structures of the compounds were established by IR, ¹H NMR and mass spectral analysis. The data revealed that compound 3s (99–100% at 10 μM concentration) completely inhibit the selected five human cancer cell lines as compared to standard flavopiridol and gemcitabine (70–90% at 700 nM and 500 nM concentrations, respectively), followed by 3a, 3n, 3o, 3p, 3q, 3r. Among the tested compounds 3l, 3m, 3r, and 3s exhibited promising anti-inflammatory activity against TNF-α and IL-6 with 90–100% inhibition at 10 μM concentration. DPPH free radical scavenging activity was given by the compounds 3o, 3n, 3l, 3r, 3m, 3a, 3p, 3c and 3s at 1 mM concentration. Overall, 3s was obtained as lead compound with promising anticancer, anti-inflammatory and antioxidant activities. Bioavailability of compounds were checked by in vitro cytotoxicity study and confirmed to be nontoxic. The structure activity relationship (SAR) and in silico drug relevant properties (HBDs, HBAs, PSA, c Log P, ionization potential, molecular weight, E_HOMO and E_LUMO) further confirmed that the compounds were potential candidates for future drug discovery study.