Expression of recombinant human cyclooxygenase isoenzymes in transfected COS-7 cells in vitro and inhibition by tenoxicam, indomethacin and aspirin

Discovery of pyrazole N-aryl sulfonate: A novel and highly potent cyclooxygenase-2 (COX-2) selective inhibitors

Based on a new pyrazole sulfonate synthetic method, a novel class of molecules with a basic structure of pyrazole N-aryl sulfonate have been designed and synthesized. The interest in conducting intensive research stems from quite evident anti-inflammatory effects exhibited by the compounds in preliminary animal experiments. A series of compounds were synthesized by different substitutions of the R¹, R², and R³ groups. Within the series, 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and phenyl 5-methyl-3-(4-(trifluoromethyl) phenyl)-1H-pyrazole-1-sulfonate exhibited excellent anti-inflammatory activity (% inhibition of auricular edemas = 27.0 and 35.9, respectively); the in vivo analgesic activity of phenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate was confirmed to be effective (inhibition ratio of writhing = 50.7% and 48.5% separately), and compounds phenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate , 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate were identified as selective COX-2 inhibitors (SI = 455, 10,497 and >189 severally). In Acute Oral Toxicity assays conducted in vivo, the lethal dose 50 (LD₅₀) of 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate to mice was >2000 mg/kg BW.

New applied pharmacological approach/trend on utilization of agro-industrial wastes

This study aimed to transform the locally available lignocellulosic residual palm frond (PF) and rice straw (RS) wastes into multifunction added products like methylated cellulose and sulfated and phosphorylated hemicelluloses by simple processes. Hydrolysis with 2 N sulfuric acid was the most suitable reaction for microcrystalline cellulose production. The characteristics of the prepared products were studied to obtain the optimum reaction conditions. Palm frond hemicellulose (PFHC) recorded the highest antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans (22, 22, 26 mm), respectively, and phosphorylated palm frond hemicellulose (PPFHC) exhibited the highest potential antioxidant activity of approximately 60%, suggesting a possible correlation between the two bioactivities. Most of extracted celluloses and their derivatives had a variety of promising probiotic activities which are expected to reduce the side effects of the gastric mucosa and possibly play a role in curing the gastric ulcer. Accordingly, the determination of anti-inflammatory and gastroprotective activity results revealed that methylcellulose, sulfated and phosphorylated hemicelluloses showed anti-inflammatory and gastroprotective activities and the capability of all tested compounds to ameliorate the ethanol-induced gastric ulcer in rats' stomach. All results recommended PF and RS and their derivatives to be used as a medicinal food.

Comparison of pharmacokinetic and pharmacodynamic profiles of aspirin following oral gavage and diet dosing in rats

Aspirin is one of the oldest drugs and has been purported to have multiple beneficial effects, including prevention of cardiovascular disease and cancer, in addition to its original indication for treatment of inflammation, fever and pain. In cancer chemoprevention studies using animal models, two methods of aspirin administration have been employed: oral gavage and diet. The untested assumption was that exposure and the resultant pharmacological effects are similar for these two administration methods when dosing is normalized on the basis of mg/kg body weight/day. This study examined and compared time-dependent plasma and colon mucosal concentrations of aspirin metabolite salicylate (aspirin concentrations were below level of quantification), plasma thromboxane B(2) concentrations, and colon mucosal prostaglandin E(2) concentration following these two different dosing paradigms in rats. Diet dosing yielded relatively constant plasma and colon salicylate concentration vs. time profiles. On the other hand, oral gavage dosing led to a rapid peak followed by a fast decline in salicylate concentration in both plasma and colon. Nevertheless, the exposure as measured by the area under plasma or colon concentration-time curve of salicylate was linearly related to dose irrespective of the dosing method. Linear relationships were also observed between colon and plasma salicylate areas under the curve and between colon prostaglandin E(2) and plasma thromboxane B(2) areas under the curve. Therefore, more easily accessible plasma salicylate and thromboxane B(2) concentrations were representative of the salicylate exposure and prostaglandin E(2) pharmacodynamic biomarker in the target colon, respectively.

Anti-inflammatory effects of a triterpenoid isolated from Wilbrandia ebracteata Cogn

Wilbrandia ebracteata (WE), a Brazilian medicinal plant used in folk medicine for the treatment of rheumatic diseases, displays anti-inflammatory properties and constitutes a rich source of cucurbitacins and cucurbitacin-related compounds. The current study investigated the potential anti-inflammatory properties of Dihydrocucurbitacin B (DHCB), a cucurbitacin-derived compound isolated from roots of WE, in some in vivo and in vitro experimental models. Intraperitoneal treatment of mice with DHCB reduced both carrageenan-induced paw edema (0.3, 1 and 3 mg/kg caused inhibitions of 26, 44 and 56 % at 2 h after stimulation, respectively) and pleurisy (10 mg/kg inhibited leukocyte numbers and LTB(4) levels in the pleural fluid by 51 and 75% at 6 h after cavity challenge, respectively). In vitro, DHCB (up to 10 microg/mL) failed to modify LTB(4) production by human neutrophils or PGE(2) production by COS-7 cells transfected with COX-1, but PGE(2) production by COX-2 transfected COS-7 cells was markedly inhibited (by 72%). The levels of COX-1 or COX-2 proteins in IL-1alpha-stimulated NIH3T3 cells were unaffected by DHCB. The results corroborate the potential anti-inflammatory properties ascribed to W. ebracteata Cogn. in folk medicine and suggest that they might be attributed, at least in part, to the capacity of one of this plants main constituents, DHCB, to inhibit COX-2 activity (but not its expression) during inflammation.

The involvement of nuclear factor-kappa B in cyclooxygenase-2 overexpression in murine colon cancer cells transduced with herpes simplex virus thymidine kinase gene

We have previously reported that transduction of murine colon cancer cells (MC38) with herpes simplex virus thymidine kinase (HSV-tk) gene results in a significant enhancement of tumor growth rate in vivo and overexpression of cyclooxygenase-2 (COX-2). Our current study aimed to investigate the involvement of nuclear factor-kappa B (NF-kappaB), a pivotal transcriptional regulator of COX-2, in the upregulation of COX-2 expression by HSV-tk. It was found that HSV-tk gene transduction of MC38 cells results in significantly enhanced NF-kappaB activity, increased phosphorylation and degradation of inhibitor-kappa Balpha (IkappaBalpha) and enhanced translocation of NF-kappaB to the nucleus. Treatment of HSV-tk-transduced MC38 cells with sulfasalazine, a potent NF-kappaB inhibitor, led to dose-dependent inhibition of NF-kappaB activity, IkappaB phosphorylation and nuclear translocation of NF-kappaB, accompanied by significantly decreased COX-2 expression and reduced release of prostaglandin E2. Transient transfection experiments with COX-2 promoter constructs fused to luciferase reporter gene revealed that mutation in NF-kappaB-responsive element of COX-2 promoter significantly reduced promoter activity in HSV-tk-transduced MC38 and COS-7 cells, whereas it had no effect on promoter activity in the respective wild-type cells. At last, it was found that HSV-tk gene transduction causes significant enhancement of NF-kappaB activity and COX-2 expression in two additional tumor cell lines, 9L and T24. These findings suggest that HSV-tk gene transduction results in NF-kappaB pathway activation, which is essential for COX-2 overexpression by HSV-tk.

Comparative study of anti-inflammatory and ulcerogenic activities of different cyclo-oxygenase inhibitors

The aim of the present work was to study the in vivo anti-inflammatory activity of six NSAIDs, ibuprofen, diclofenac, nimesulide, meloxicam, celecoxib and rofecoxib, using the rat air-pouch model of inflammation to characterize the ability of these drugs to induce gastric damage and PGE(2) inhibition. Selective compounds were observed to have no ulcerogenic properties at anti-inflammatory doses; however, these drugs were weaker inhibitors of several inflammatory aspects such as cell influx and exudate formation. In contrast, the non-selective and preferential compounds present anti-inflammatory properties at lower doses than presented by selective drugs. At anti-inflammatory doses, only meloxicam and ibuprofen produced gastric damage and inhibition of PGE(2) synthesis, suggesting that ulcerogenic properties of NSAIDs cannot be predicted by their selectivity index, since meloxicam demonstrates ulcerogenic properties despite its preferential profile.

Clinical tolerability of perioperative tenoxicam in 1001 patients – a prospective, controlled, double-blind, multi-centre study

We investigated adverse events (AEs) associated with perioperative tenoxicam in a double-blind, prospective, randomised study. Patients undergoing surgery, screened for contraindications to non-steroidal anti-inflammatory drug, received tenoxicam (n=750) on 2843 days or placebo (n=251) on 988 days, in courses of 1-12 days. There was no increase in the overall incidence of side effects with tenoxicam (33 vs 38% with placebo: P=0.15), or in major side effects (3.9 vs 2.0% with placebo: P=0.11). Of major side effects possibly or probably related to tenoxicam (2.1 vs 1.2% with placebo: P=0.26), all but one involved post-operative surgical site bleeding. However, in the subgroup of patients undergoing otorhinolaryngology surgery, surgical site bleeding occurred in 18 of 171 (10.5%) patients on tenoxicam and one of 57 (1.8%) on placebo (P=0.026); of these, nine in the tenoxicam group and 0 in the placebo were classified as major (P=0.07). One patient on tenoxicam experienced endoscopically proven duodenal ulceration with malaena. In conclusion, perioperative tenoxicam is well tolerated in comparison with placebo and the incidence of drug-related major AEs (other than post-operative bleeding) is no greater than 1 in 150 in low risk patients, but in patients undergoing otorhinolaryngological surgery there may be an increased risk of post-operative bleeding.

Nitric oxide and cyclooxygenase may participate in the analgesic and anti-inflammatory effect of the cucurbitacins fraction from Wilbrandia ebracteata

Wilbrandia ebracteata is a medicinal plant from South America used in folk medicine for the treatment of chronic rheumatic diseases. We have shown that the high performance liquid chromatography-characterized (HPLC) dichloromethane fraction isolated from Wilbrandia ebracteata (WEDC) inhibits the parameters observed in experimental models of inflammation in vivo and in vitro. In the present study, we extend our previous observations on the analgesic effects of WEDC by investigating its actions using the hot plate test and zymosan-induced writhing test in mice, as well as zymosan-induced arthritis in rats evaluating articular inflammatory pain, cell migration and determination of NO release into the joint exudate. The effect of WEDC on the activity of COX-1 and COX-2 in vitro and its ulcerogenic capacity in vivo were also investigated. The oral treatment of the animals with WEDC (1-10 mg/kg) produced a significant, dose-dependent reduction of articular incapacitation and abdominal contortions in the writhing test. The same effect was not observed in the hot plate and rota-rod tests. WEDC also reduced nitrite release into the zymosan-inflamed joints. In the evaluation of COX activity, we observed that WEDC was able to selectively inhibit COX-2 but not COX-1 activity in COS-7 cells. Moreover, WEDC treatment did not show gastrointestinal toxicity. Our data confirm the anti-nociceptive activities of the WEDC and indicate that this effect could be associated with inhibition of cyclooxygenase-2 (COX-2) and nitric oxide release. The effects could be attributed to cucurbitacins since several of these were isolated from the WEDC.

Anti-inflammatory effects of the products from Wilbrandia ebracteata on carrageenan-induced pleurisy in mice

Wilbrandia ebracteata Cogn. (Cucurbitaceae) is commonly known in Brazil as "Taiuia". The roots are employed in folk medicine for the treatment of several diseases, such as rheumatic disease. This study has evaluated the anti-inflammatory action of dicloromethane fraction (F-DCM), purified fraction (PFIII) and Cucurbitacin B extracted from crude extract of W. ebracteata in experimental models in vivo. The F-DCM (0.3 to 10 mg.kg(-1), i.p. or 3 to 30 mg.kg(-1) p.o.) produced significant but not dose-dependent inhibition of the carrageenan-induced cell influx and exsudate leakage in the pleural cavity of mice. The F-DCM 0.01 to 10 mg.kg(-1), i.p. or 0.1 to 10 mg.kg(-1) p.o.) decreased the levels of PGE2 in the exsudate leakage induced by carrageenan in the pleural cavity after 4 h with a calculated ID50 of 0.01 (0.002-0.09, i.p.) and 0.29 (0.05-1.45, p.o.) mg.kg(-1). The PFIII (3 mg.kg(-1), i.p.) inhibited 80% of cell migration (1.50 +/- 0.09 x 10(6) cells/cavity) and exsudate leakage by about 50% (3.09 +/- 0.71 microg/ml) in relation to the control group. Cucurbitacin B (0.1 mg.kg(-1), i.p.), the main compound of PFIII, reduced significantly the levels of PGE2 in the exsudate leakage by 40.7% (10.41 +/- 2.67 ng.ml(-1)). These data show that the active principle(s) present in the F-DCM of W. ebracteata elicited pronounced anti-inflammatory effects when assessed by i.p. or p.o. routes, as well as PFIII. The F-DCM was also able to prevent PGE2 formation in exsudate leakage induced by carrageenan, as well as Cucurbitacin B, its active principle. These results indicate that the anti-inflammatory activity of Wilbrandia ebracteata can be related with the inhibition of the production of PGE2.

Systematic pharmacological approach to the characterization of NSAIDs

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of inflammatory diseases. NSAIDs inhibit cyclooxygenase (COX), the rate limiting enzyme responsible for the conversion of arachidonic acid into prostaglandins. Recent studies have shown the existence of two isoforms of cyclooxygenase: COX-1, now often referred to as the constitutive form, and COX-2, an inducible form which is the major isoenzyme involved in prostaglandin synthesis in inflammation and other pathological situations. Since inhibition of prostaglandin production in tissues where they play a physiological role leads to important side effects, a COX-2 preferential inhibitor would present therapeutical advantages. In the present study, we evaluated the inhibitory properties of cyclooxygenase inhibitors on human COX-1 and COX-2 using a heterologous expression system. We investigated instantaneous inhibition and pre-incubation inhibition as well as time recovery of cyclooxygenase activity assays with the aid of four NSAIDs: mefenamic acid, indomethacin, aspirin and NS-398. Our results demonstrate that instantaneous inhibition assays have little correlation with clinical results. Inhibition assays using pre-incubation with the drugs tested, however, more closely resemble the data from in vivo studies. Cyclooxygenase recovery assays enabled better characterization of simple competitive inhibitors, competitive reversible time-dependent inhibitors and irreversible time-dependent inhibitors. The data illustrate the usefulness of our system in allowing a better determination of the pharmacological characteristics of NSAIDs as well as permitting a comparison among different drugs.