Synthesis and anti-inflammatory activity evaluation of NO-releasing furoxan/1,2,4-triazole hybrid derivatives

An efficient synthesis method was developed for furoxan/1,2,4-triazole hybrids 5a-k from methyl 5-(halomethyl)-1-aryl-1H-1,2,4-triazole-3-carboxylates 1 through two-steps reaction including hydrolyzation and esterification. All of the furoxan/1,2,4-triazole hybrid derivatives were characterized by spectroscopy. On the other hand, the influence of newly synthesized multi-substituted 1,2,4-triazoles on the exogenous NO release ability, in vitro and in vivo anti-inflammatory activity, and in silico predictions were experimentally evaluated. Based on the exogenous NO release ability study and SAR studies of in vitro anti-inflammatory activity, all of compounds 5a-k exhibited slightly NO release ability and potential anti-inflammatory activity on LPS-induced RAW264.7 cells (IC₅₀ = 5.74-15.3 μM) compared to Celecoxib (IC₅₀ = 16.5 μM) and Indomethacin (IC₅₀ = 56.8 μM). Furthermore, compounds 5a-k were also subjected to in vitro COX-1/COX-2 inhibition assays. Particularly, compound 5f exhibited extraordinary COX-2 inhibition (IC₅₀ = 0.0455 μM) and selectivity (SI = 209). In addition, compound 5f was also examined in vivo pro-inflammatory cytokine productions and gastric safety and possessed the better inhibition of cytokine and safety compared with Indomethacin at the same concentration. Through the molecular modeling and in silico physicochemical and pharmacokinetic properties prediction, compound 5f was stabilized in COX-2 active binding site and possessed the fundamental strong H-bond interaction with Arg499 to form the significant physicochemical and pharmacological properties as a candidate drug. Following the in vitro, in vivo, and in silico study results, compound 5f demonstrated to be a potential anti-inflammatory agent and had comparable effects with Celecoxib.

Recent development on COX-2 inhibitors as promising anti-inflammatory agents: The past 10 years

Cyclooxygenases play a vital role in inflammation and are responsible for the production of prostaglandins. Two cyclooxygenases are described, the constitutive cyclooxygenase-1 and the inducible cyclooxygenase-2, for which the target inhibitors are the non-steroidal anti-inflammatory drugs (NSAIDs). Prostaglandins are a class of lipid compounds that mediate acute and chronic inflammation. NSAIDs are the most frequent choices for treatment of inflammation. Nevertheless, currently used anti-inflammatory drugs have become associated with a variety of adverse effects which lead to diminished output even market withdrawal. Recently, more studies have been carried out on searching novel selective COX-2 inhibitors with safety profiles. In this review, we highlight the various structural classes of organic and natural scaffolds with efficient COX-2 inhibitory activity reported during 2011–2021. It will be valuable for pharmaceutical scientists to read up on the current chemicals to pave the way for subsequent research.

Ablation of conceptus PTGS2 expression does not alter early conceptus development and establishment of pregnancy in the pig†

Pig conceptuses secrete estrogens (E2), interleukin 1 beta 2 (IL1B2), and prostaglandins (PGs) during the period of rapid trophoblast elongation and establishment of pregnancy. Previous studies established that IL1B2 is essential for rapid conceptus elongation, whereas E2 is not essential for conceptus elongation or early maintenance of the corpora lutea. The objective of the present study was to determine if conceptus expression of prostaglandin-endoperoxide synthase 2 (PTGS2) and release of PG are important for early development and establishment of pregnancy. To understand the role of PTGS2 in conceptus elongation and pregnancy establishment, a loss-of-function study was conducted by editing PTGS2 using CRISPR/Cas9 technology. Wild-type (PTGS2+/+) and null (PTGS2-/-) fibroblast cells were used to create embryos through somatic cell nuclear transfer. Immunolocalization of PTGS2 and PG production was absent in cultured PTGS2-/- blastocysts on day 7. PTGS2+/+ and PTGS2-/- blastocysts were transferred into surrogate gilts, and the reproductive tracts were collected on either days 14, 17, or 35 of pregnancy. After flushing the uterus on days 14 and 17, filamentous conceptuses were cultured for 3 h to determine PG production. Conceptus release of total PG, prostaglandin F2⍺ (PGF2α), and PGE in culture media was lower with PTGS2-/- conceptuses compared to PTGS2+/+ conceptuses. However, the total PG, PGF2α, and PGE content in the uterine flushings was not different. PTGS2-/- conceptus surrogates allowed to continue pregnancy were maintained beyond 30 days of gestation. These results indicate that pig conceptus PTGS2 is not essential for early development and establishment of pregnancy in the pig.

Investigation of isomerization of dexibuprofen in a ball mill using chiral capillary electrophoresis

Besides the racemate, the S-enantiomer of ibuprofen (Ibu) is used for the treatment of inflammation and pain. Since the configurational stability of S-Ibu in solid state is of interest, it was studied by means of ball milling experiments. For the evaluation of the enantiomeric composition, a chiral CE method was developed and validated according to the ICH guideline Q2(R1). The addition of Mg²⁺ , Ca²⁺ , or Zn²⁺ ions to the background electrolyte (BGE) was found to improve Ibu enantioresolution. Chiral separation of Ibu enantiomers was achieved on a 60.2 cm (50.0 cm effective length) x 75 μm fused-silica capillary using a background electrolyte (BGE) composed of 50 mM sodium acetate, 10 mM magnesium acetate tetrahydrate, and 35 mM heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CD) as chiral selector. The quantification of R-Ibu in the mixture was performed using the normalization procedure. Linearity was evaluated in the range of 0.68-5.49% R-Ibu (R² = 0.999), recovery was found to range between 97 and 103%, the RSD of intra- and interday precision below 2.5%, and the limit of quantification for R- in S-Ibu was calculated to be 0.21% (extrapolated) and 0.15% (dilution of racemic ibuprofen), respectively. Isomerization of S-Ibu was observed under basic conditions by applying long milling times and high milling frequencies.

Molecular Modelling, Synthesis and Evaluation of Flavone and Flavanone Scaffolds as Anti-inflammatory Agents

OBJECTIVE

The objective of the study was to develop new Cyclooxygenase-2 inhibitors as anti-inflammatory agents from the synthetic route.

MATERIALS AND METHODS

The 2-phenyl-4H-chromen-4-one and 2-phenyl-2,3-dihydro-4H-chromenone hybrids were synthesised and characterised by using UV, IR, ¹H-NMR, and mass spectrometry. An attempt was made for consolidated lead flavones and flavanones scaffolds by determining ADME/ T properties. Molecular docking simulations were performed by using Autodock.4 to understand the binding interaction over the targeted enzyme Cyclooxygenase-2. The titled compounds were evaluated for various in-vitro models for antioxidant and anti-inflammatory activities and based upon the IC₅₀ values, the selected compounds were screened for in vivo anti-inflammatory activity by both acute and chronic models.

RESULTS AND DISCUSSION

Twenty titled compounds were synthesised and elucidated their structure for confirmation of their functional groups by various spectroscopic techniques. Among the synthesized compounds, flavone derivatives such as HFc (7-hydroxy-3-(4-methoxy phenyl)-4H-chromen-4- one), HF_d (2-(2,4-di methoxy-phenyl)-7-hydroxy-4H-chromen-4-one) and HFe (7-hydroxy-2- (thiophen-2-yl)-4H-chromen-4-one) produced higher potency. Flavanone derivatives HFAc (7- hydroxy-2-(4-hydroxy-3-methoxy phenyl)-2,3-dihydro-4H-chromen-4-one), HFAb (7-hydroxy-2-(4- methoxy phenyl)-2,3-dihydro-4H-chromen-4-one) and HFA_d (7-hydroxy-2-(thiophen-2-yl)-2,3- dihydro-4H-chromen-4-one) showed significant anti-inflammatory activity compared to the standard COX-2 inhibitors.

CONCLUSION

The flavone and flavanone scaffolds possess their excellent inhibitory action over the Cyclooxygenase-2 and act as a potential anti-inflammatory agent. The results of computational studies were also significantly correlated and concluded that those naturally mimicking flavonoid analogues were tremendous candidates to fight against the inflammatory diseases in drug discovery.

Gastroprotective potential of hydro-alcoholic extract of Pattanga (Caesalpinia sappan Linn.)

ETHNO-PHARMACOLOGICAL RELEVANCE

Pattanga is botanically equated as Caesalpinia sappan Linn. (Family: Caesalpiniaceae) and is used in Ayurveda system of medicine since ages. According to Ayurveda, useful part is Heartwood, which is bitter, astringent and acrid and is useful in vitiated conditions of vata and pitta, burning sensation, wounds, ulcers, leprosy, skin diseases, menorrhagia, leucorrhea, and diabetes. It is used as a major ingredient in Ayurvedic formulations and preparations like Patrangasava, Chandanadya Thalia, and Karpuradyarka.

AIM OF THE STUDY

The present study is planned to evaluate the gastroprotective activity of the selected Ayurvedic drug using three different in vivo gastric ulcer models, so as to provide scientific evidence for the Ayurvedic claims.

MATERIALS AND METHODS

For this study, Wistar albino rats fasted overnight were selected. The hydroalcoholic extract of Caesalpinia sappan heartwood at the dose level 250 and 500mg/kg body weight was selected and administered orally before necrotizing agents. Antioxidant and antiulcer parameters were evaluated and the stomach samples were subjected for histopathological studies. In addition, PGE2 estimation and protein expressions of COX-1, COX-2 and iNOS were analyzed by Western blot. The plant extract was subjected to LCMS/MS analysis. In addition, Cytoprotective effect in isolated gastric mucosal cells, TUNEL Assay, Acid neutralizing capacity assay, H⁺/K⁺ ATPase inhibitory assay were performed.

RESULTS

The ulcer protection was found to be 92%, 86% and 64% against ethanol, NSAID and pylorus ligation induced ulcer respectively. The hydro-alcoholic extract of C. sappan heartwood exhibited cytoprotective effect with 76.82% reduction against indomethacin-induced cytotoxicity at the concentration of 25µg/ml. C. sappan showed 63.91% inhibition in H⁺/K⁺ ATPase inhibitory assay at the concentration 500µg/ml.

CONCLUSIONS

Our results depict that Caesalpinia sappan heartwood possesses gastroprotective activity, possibly mediated through cytoprotection and antioxidant mechanisms. The data obtained in the present study provides scientific support for the traditional use of Caesalpinia sappan in the management of peptic ulcer.

NSAIDs in Dermatologic Therapy: Review and Preview

Background:

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been an important therapy in the treatment of a large number of cutaneous pathologies for more than three decades.

Objective:

In this retrospective review, we document the use of NSAIDs in more than 15 common and uncommon dermatoses, including acne, psoriasis, sunburn, erythema nodosum, cryoglobulinemia, Sweet's syndrome, systemic mastocytosis, as well as urticarial, livedoid, and nodular vasculitis. NSAIDs act mainly by inhibiting prostaglandin synthesis by the cyclooxygenase (COX) pathway.

Conclusion:

Recent studies link prostaglandin to cutaneous carcinogenesis, thus expanding the dermatologic use of NSAIDs. They may be effective in the treatment and prevention of non-melanoma skin cancer, and specific COX-2 inhibitors promise safer, broader, long-term use of these pharmacologically innovative drugs.

Serotonin and histamine mediate gastroprotective effect of fluoxetine against experimentally-induced ulcers in rats

Research in the treatment of gastric ulcer has involved the investigation of new alternatives, such as anti-depressant drugs. The present study was designed to investigate the gastroprotective effects of fluoxetine against indomethacin and alcohol induced gastric ulcers in rats and the potential mechanisms of that effect. Fluoxetine (20 mg/kg) was administered IP for 14 days. For comparative purposes, other rats were treated with ranitidine (30 mg/kg). Thereafter, after 24 h of fasting, INDO (100 mg/kg) or absolute alcohol (5 ml/kg) was administered to all rats (saline was administered to naïve controls) and rats in each group were sacrificed 5 h (for INDO rats) or 1 h (for alcohol rats) later. Macroscopic examination revealed that both fluoxetine and ranitidine decreased ulcer scores in variable ratios, which was supported by microscopic histopathological examination. Biochemical analysis of fluoxetine- or ranitidine-pre-treated host tissues demonstrated reductions in tumor necrosis factor (TNF)-α and myeloperoxidase (MPO) levels and concomitant increases in gastric pH, nitric oxide (NO) and reduced glutathione (GSH) contents. Fluoxetine, more than ranitidine, also resulted in serotonin and histamine levels nearest to control values. Moreover, immuno-histochemical analysis showed that fluoxetine markedly enhanced expression of cyclo-oxygenases COX-1 and COX-2 in both models; in comparison, ranitidine did not affect COX-1 expression in either ulcer model but caused moderate increases in COX-2 expression in INDO-induced hosts and high expression in alcohol-induced hosts. The results here indicated fluoxetine exhibited better gastroprotective effects than ranitidine and this could be due to anti-secretory, anti-oxidant, anti-inflammatory and anti-histaminic effects of the drug, as well as a stabilization of gastric serotonin levels.

Anti-inflammatory effect of certain dimethoxy flavones

OBJECTIVE

The aim of the present study was to evaluate the anti-inflammatory effect of four dimethoxy flavone derivatives; 7,2'-dimethoxy flavone, 7,3'-dimethoxy flavone, 7,4'-dimethoxy flavone and 7,8,-dimethoxy flavone and to investigate the possible cellular mechanisms involved.

MATERIALS AND METHODS

The acute anti-inflammatory effect of dimethoxy flavones was investigated by carrageenan induced hind paw oedema in rats. Further, the effect of dimethoxy flavones on certain mediators of pain and inflammation like cyclooxygenases (COX-1 and COX-2), pro-inflammatory cytokines (IL-1β and TNF-α) and free radical scavenging activity (NO and LPO) were investigated by using in vitro tests.

RESULTS

The investigated dimethoxy flavones produced a significant, dose and time dependent reduction of carrageenan induced paw oedema in rats with a maximum inhibition of 52.4% observed for 7,4'-dimethoxy flavone. Although, the test compounds inhibited both the isoforms of cyclooxygenase, a higher degree of inhibition on COX-2 was evident. A concentration dependent inhibition of other inflammatory cytokines like tumor necrosis factor-α and interleukin-1β was identified in the present study. 7,4'-dimethoxy flavone was found to be maximally effective in inhibiting nitrite ion free radical generation and 7,8-dimethoxy flavone was more active in inhibiting lipid peroxidation than the other compounds.

CONCLUSION

The results of the present study reveal the anti-inflammatory action of the investigated dimethoxy flavones. Inhibition of cyclooxygenases, cytokines and reactive oxygen species, observed in subsequent experiments may be suggested as possible mechanisms involved in the action of these compounds.

Acute and chronic toxicity, cytochrome p450 enzyme inhibition, and HERG channel blockade studies with a polyherbal, ayurvedic formulation for inflammation

Ayurvedic plants are known for thousands of years to have anti-inflammatory and antiarthritic effect. We have recently shown that BV-9238, a proprietary formulation of Withania somnifera, Boswellia serrata, Zingiber officinale, and Curcuma longa, inhibits LPS-induced TNF-alpha and nitric oxide production from mouse macrophage and reduces inflammation in different animal models. To evaluate the safety parameters of BV-9238, we conducted a cytotoxicity study in RAW 264.7 cells (0.005–1 mg/mL) by MTT/formazan method, an acute single dose (2–10 g/kg bodyweight) toxicity study and a 180-day chronic study with 1 g and 2 g/kg bodyweight in Sprague Dawley rats. Some sedation, ptosis, and ataxia were observed for first 15–20 min in very high acute doses and hence not used for further chronic studies. At the end of 180 days, gross and histopathology, blood cell counts, liver and renal functions were all at normal levels. Further, a modest attempt was made to assess the effects of BV-9238 (0.5 µg/mL) on six major human cytochrome P450 enzymes and ³H radioligand binding assay with human hERG receptors. BV-9238 did not show any significant inhibition of these enzymes at the tested dose. All these suggest that BV-9238 has potential as a safe and well tolerated anti-inflammatory formulation for future use.

Anti-inflammatory effects of Polygonum minus (Huds) extract (Lineminus™) in in-vitro enzyme assays and carrageenan induced paw edema

Background

The study was aimed to evaluate the anti-inflammatory activity of ethanolic and aqueous extracts of Polygonum minus (Huds) using in vitro and in vivo approaches.

Methods

The in vitro tests used to evaluate ethanolic extract are cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), lipooxygenase (5-LOX), secretory phospholipase-A2 (sPLA2) inhibition assay whilst the in-vivo effect was measured by the ability of aqueous extracts to reduce paw edema induced by λ-carrageenan, in rats.

Results

The ethanolic extract inhibited the activities of 5-LOX and COX-1(p < 0.05) whilst the inhibitory effect on COX-2 was only moderate. A marked inhibition of 5-LOX was observed at 30 μg/ ml. The extract did not inhibit the activity of sPLA2. The ability of the ethanolic extracts of Polygonum minus to inhibit both 5-LOX and COX, prompted a study to evaluate the effects of using an aqueous extract of Polygonum minus(Lineminus^TM); as this would be more suitable for future clinical testing. The anti-inhibitory activity of the aqueous extract from this plant was evaluated using a rat model where inflammation was induced in the paws by injection of λ-carrageenan. The aqueous extracts from Polygonum minus administered at doses of 100 and 300 mg/kg body weight (b.w.), significantly (p < 0.01) reduced paw edema induced by λ-carrageenan in the experimental model, at 4 h compared to the vehicle control. Furthermore, administration of 100 mg/kg b.w. or 300 mg/kg b.w. completely reduced inflammation of the paw 4 h after injection.

Conclusion

These findings suggest that aqueous extract of Polygonum minus possesses potent anti-inflammatory activities.

Interaction of nonsteroidal anti-inflammatory drugs with membranes: in vitro assessment and relevance for their biological actions

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used drugs in the world due to their anti-inflammatory, analgesic and antipyretic properties. Nevertheless, the consumption of these drugs is still associated with the occurrence of a wide spectrum of adverse effects. Regarding the major role of membranes in cellular events, the hypothesis that the biological actions of NSAIDs may be related to their effect at the membrane level has triggered the in vitro assessment of NSAIDs-membrane interactions. The use of membrane mimetic models, cell cultures, a wide range of experimental techniques and molecular dynamics simulations has been providing significant information about drugs partition and location within membranes and also about their effect on diverse membrane properties. These studies have indeed been providing evidences that the effect of NSAIDs at membrane level may be an additional mechanism of action and toxicity of NSAIDs. In fact, the pharmacokinetic properties of NSAIDs are closely related to the ability of these drugs to interact and overcome biological membranes. Moreover, the therapeutic actions of NSAIDs may also result from the indirect inhibition of cyclooxygenase due to the disturbing effect of NSAIDs on membrane properties. Furthermore, increasing evidences suggest that the disordering effects of these drugs on membranes may be in the basis of the NSAIDs-induced toxicity in diverse organ systems. Overall, the study of NSAIDs-membrane interactions has proved to be not only important for the better understanding of their pharmacological actions, but also for the rational development of new approaches to overcome NSAIDs adverse effects.

Roles of COX inhibition in pathogenesis of NSAID-induced small intestinal damage

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin decrease mucosal PGE(2) content by inhibiting cyclooxygenase (COX) activity and produce damage in the small intestine. The development of intestinal lesions induced by indomethacin was accompanied by increases in intestinal motility, enterobacterial invasion, and myeloperoxidase (MPO) as well as inducible nitric oxide synthase (iNOS) activity, together with the up-regulation of COX-2 and iNOS mRNA expression. Neither SC-560, a selective COX-1 inhibitor, nor rofecoxib, a selective COX-2 inhibitor, alone caused intestinal damage, but their combined administration provoked lesions in the small intestine. SC-560, but not rofecoxib, caused intestinal hypermotility, bacterial invasion and the expression of COX-2 as well as iNOS mRNA, yet the iNOS and MPO activity was increased only when rofecoxib was administered together with SC-560. Although SC-560 inhibited PG production, the level of PGE(2) recovered in a rofecoxib-dependent manner. The intestinal hypermotility in response to indomethacin was prevented by both 16,16-dimethyl PGE(2) and atropine but not by ampicillin, yet all these agents inhibited not only the bacterial invasion but also the expression of COX-2 as well as the iNOS activity in the intestinal mucosa following indomethacin treatment, thereby preventing the intestinal damage. These results suggest that inhibition of COX-1, despite causing intestinal hypermotility, bacterial invasion and iNOS expression, up-regulates the expression of COX-2, and the PGE(2) derived from COX-2 counteracts the deleterious events caused by COX-1 inhibition and maintains mucosal integrity. These sequences of events explain why intestinal damage occurs when both COX-1 and COX-2 are inhibited.

Aspirin in cardiology--benefits and risks

AIMS

To review the current knowledge of the benefits and risks of long-term aspirin therapy for the prevention of cardiovascular disease.

METHODS

Relevant articles published in English between 1996 and 2006 were obtained from the Current Contents Science Edition, EMBASE and MEDLINE databases.

RESULTS

Secondary aspirin prophylaxis is effective in reducing the risk of ischaemic events in patients with cardiovascular disease. However, its utility in reducing primary ischaemic events is more controversial; it appears to reduce the incidence of ischaemic stroke, but increase the incidence of haemorrhagic stroke. Aspirin therapy can also lead to an increased risk of gastrointestinal ulcers, upper gastrointestinal bleeding and other haemorrhagic complications. Lower doses of aspirin are associated with a reduced risk of gastrointestinal side effects and are equally effective in reducing cardiovascular risk. Co-therapy with non-steroidal anti-inflammatory drugs, clopidogrel or warfarin increases the risk of gastrointestinal side effects, while co-therapy with proton pump inhibitors reduces it.

CONCLUSIONS

Both the benefits and risks need to be considered carefully when prescribing aspirin, particularly in primary prevention. Patients should be prescribed lower doses rather than higher doses of aspirin in line with prescribing guidelines. Co-prescription of a proton pump inhibitors may be necessary in patients at high risk for upper gastrointestinal complications.

A new 14,15-dinor-labdane Glucoside from Crassocephalum Mannii

A new 14,15-dinor-labdane glucoside, named crassoside A (1), was isolated from the aerial parts of Crassocephalum mannii. The structure of 1 was elucidated on the basis of spectroscopic analysis (1H NMR, 13C NMR, HMQC, HMBC and NOEs). Compound 1 demonstrated a low inhibitory effect against COX-1, but was inactive against COX-2.

Cyclooxygenase (COX)-1 and -2 inhibitory labdane diterpenes from Crassocephalum mannii

Two new labdane diterpenes, 8alpha,19-dihydroxylabd-13 E-en-15-oic acid (1) and 13,14,15,16-tetranorlabdane-8alpha,12,14-triol (2), as well as an acetylated derivative, 8alpha-O-beta-D-glucopyranosyllabd-13 E-ene-15,19-diol-8alpha-2',3',4',6'-hexaacetate (3a), were isolated from the aerial parts of Crassocephalum mannii. The structures of 1, 2, and 3a were elucidated by spectroscopic data analysis. Selective inhibitory activity for 1 and 2 and their acetate derivatives, 1a and 2a, against cyclooxygenases (COX-1 and COX-2) was detected.

The effect of age on prostaglandin-synthesizing enzymes in the development of gingivitis

BACKGROUND AND OBJECTIVE

The aim of this study was to identify the expression of cyclooxygenase-1, cyclooxygenase-2, cyclooxygenase-3, and microsomal prostaglandin E synthase-1 in young and elderly subjects.

MATERIAL AND METHODS

Periodontally healthy subjects were divided into young (18-30 years, n = 7) and elderly (46-77 years, n = 7). A gingival biopsy was taken at baseline. After experimental gingivitis, clinical examination was repeated and a second biopsy was taken. The expression of cyclooxygenase-1, cyclooxygenase-2, cyclooxygenase-3, and microsomal prostaglandin E synthase-1 was analyzed by means of immunohistochemistry.

RESULTS

In both healthy age groups, cyclooxygenase-1 and microsomal prostaglandin E synthase-1 were expressed in epithelial cells, endothelial cells and fibroblast-like connective tissue cells. Cyclooxygenase-1 was found in Langerhans' cells of the epithelium. Cyclooxygenase-2 expression was observed in cells exhibiting the morphology of epithelial mitosis cells, and the expression of cyclooxygenase-2 in periodontally healthy elderly subjects was significantly lower (p < or = 0.05). Following experimental gingivitis, cyclooxygenase-1 and microsomal prostaglandin E synthase-1 expression did not change. However, the expression of cyclooxygenase-2 was significantly increased in both age groups (p < or = 0.05). Cyclooxygenase-3 was not detected in any group investigated.

CONCLUSION

Cyclooxygenase-1 and microsomal prostaglandin E synthase-1 were expressed constitutively in gingival tissue, and expression was unaffected by age or inflammation states. In contrast, the expression of cyclooxygenase-2 was weaker in elderly subjects. In the course of experimental gingivitis, cyclooxygenase-2 was induced in both age groups.

Quantitative HPLC-UV method for the determination of firocoxib from horse and dog plasma

A sensitive reversed-phase HPLC-UV method was developed for the determination of firocoxib, a novel and highly selective COX-2 inhibitor, in plasma. A 1.0 mL dog or horse plasma sample is mixed with water and passed through a hydrophobic-lipophilic copolymer solid-phase extraction column to isolate firocoxib. Quantitation is based on an external standard curve. The method has a validated limit of quantitation of 25 ng/mL and a limit of detection of 10 ng/mL. The validated upper limit of quantitation was 2500 ng/mL for horses and 10,000 ng/mL for dogs. The average recoveries ranged from 88-93% for horse plasma and 96-103% for dog plasma. The coefficient of variation in all cases was less than 10%. This method is suitable for the analysis of clinical samples from pharmacokinetic and bioequivalence studies and drug monitoring.

Simultaneous determination of ZLR-8 and its active metabolite diclofenac in dog plasma by high-performance liquid chromatography

ZLR-8 is a nitric oxide releasing derivative of diclofenac for the treatment of inflammation. In this paper, a sensitive and reliable high-performance liquid chromatography method for simultaneous determination of ZLR-8 and its active metabolite diclofenac in the plasma of beagle dogs has been developed and validated. After the addition of ketoprofen as the internal standard (IS), plasma samples were extracted with n-hexane-isopropanol (95:5, v/v) mixture solution and separated by HPLC on a reversed-phase C(18) column with a mobile phase of gradient procedure. Analytes were determined by the UV detector which was set at 280 nm. The method was proved to be sensitive and specific by testing six different plasma batches. Calibration curves of ZLR-8 and diclofenac were linear over the range 0.05-4.0 microg/mL. The within- and between-batch precisions (RSD%) were lower than 10% and accuracy ranged from 85 to 115%. The lower limit of quantification was identifiable and reproducible at 0.05 microg/mL. The proposed method has been readily implemented in preclinical pharmacokinetics studies of ZLR-8 and its active metabolite diclofeance. Representative plasma concentration vs time profiles resulting from administration of ZLR-8 to beagle dogs are presented in this communication.

Identification of 2-hydroxymethyl-4-[5-(4-methoxyphenyl)-3-trifluoromethyl-pyrazol-1-yl]-N-propionylbenzenesulfonamide sodium as a potential COX-2 inhibitor for oral and parenteral administration

Synthesis of prodrugs of orally active COX-2 inhibitor 3 involving sulfamoyl (SO(2)NH(2)) and hydroxymethyl (CH(2)OH) groups, and their biological evaluation are described. Of these prodrugs, the N-propionyl sulfonamide sodium 3k was found to be much superior to the parent compound 3 and other marketed COX-2 inhibitors in carrageenan induced rat paw edema model of inflammation due to highly elevated drug levels in systemic circulation. This prodrug has a potential both for oral as well as parenteral administration due to impressive analgesic activity, antipyretic potency, and extraordinary water solubility.

Expression of cyclooxygenase-1 and -2 in the porcine endometrium during the oestrous cycle and early pregnancy

Cyclooxygenase (COX) is the rate-limiting enzyme that catalyses the initial step in prostaglandins (PGs) production. In the present studies, endometrial COX-1 and COX-2 expression throughout the oestrous cycle and early pregnancy was analysed in pigs using real-time reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot and immunohistochemistry. There were no changes in messenger RNA (mRNA) and protein expression for COX-1 in cyclic pigs. In pregnant animals, mRNA levels of this enzyme increased on days 22-25 (p < 0.001). However, no upregulation of COX-1 protein was detected. Quantification of COX-2 mRNA expression during the oestrous cycle revealed significant increases on days 10-12 and 14 (p < 0.001 and p < 0.01 vs days 2-4, respectively). Protein levels were also increased on day 14 when compared with days 2-12 and 18-20 after oestrus. In pregnant animals, the patterns of both COX-2 mRNA and protein expression were similar. Messenger RNA levels were higher on days 16 and 22-25 (p < 0.01 vs day 10). Moreover, the protein content tended to increase on days 16 and 22-25. COX-1 and COX-2 were localized in the luminal and glandular epithelium as well as in the uterine stroma. In contrast to COX-1, a positive immunostaining reaction for COX-2 was detected only on days 12-16 after ovulation and on days 14-16 of pregnancy. In conclusion, these results indicate specific patterns of COX-1 and COX-2 expression in the porcine endometrium throughout the oestrous cycle and early pregnancy. COX-2 rather than COX-1 seems to be the primary enzyme responsible for modulated PGs production at the time of luteolysis in cyclic and during implantation in pregnant animals.

N-Acylated sulfonamide sodium salt: A prodrug of choice for the bifunctional 2-hydroxymethyl-4-(5-phenyl-3-trifluoromethyl-pyrazol-1-yl) benzenesulfonamide class of COX-2 inhibitors

Synthesis and biological evaluation of possible prodrugs of COX-2 inhibitors involving sulfonamide and hydroxymethyl groups of 2-hydroxymethyl-4-(5-phenyl-3-trifluoromethyl-pyrazol-1-yl) benzenesulfonamides are described. Out of many options, the sodium salt of N-propionyl sulfonamide demonstrated much improved pharmacological profiles and physicochemical properties suitable for oral as well as parenteral administration.

Disposition of Deracoxib in Cats After Oral Administration

The pharmacokinetics of deracoxib in seven healthy cats were determined following a single oral (1 mg/kg) dose. Minimal variability among cats was found for all estimated pharmacokinetic variables. Terminal half-life (t1/2) was 7.9 hours. The mean maximum concentration (Cmax) was 0.28 μg/mL and was measured 3.64 hours after drug administration. Deracoxib was not detectable in the plasma after 60 hours. The compounded liquid formula was accepted readily, and no adverse effects were observed. Further studies are needed to determine the efficacy and safety of deracoxib after acute and chronic use in the cat.

The gastrointestinal safety and effect on disease activity of etoricoxib, a selective cox-2 inhibitor in inflammatory bowel diseases

BACKGROUND

While traditional nonsteroidal antiinflammatory drugs (t-NSAIDs) are relatively contraindicated in patients with inflammatory bowel disease (IBD) for fear of disease aggravation, controlled clinical trials showed that cyclo-oxygenase-2 inhibitors have fewer gastrointestinal side effects than the t-NSAIDs. Etoricoxib is a new antiinflammatory inhibitor that has high Cox-2 selectivity.

OBJECTIVES

To assess the safety of etoricoxib and effect on disease activity in patients with IBD in a multicenter, double-blind, placebo-control study.

METHODS

Study group included 76 patients suffering from IBD (ulcerative colitis (UC) (38), and Crohn's disease (CD) (38)). The control group included 70 patients known to have UC (35) and Crohn's disease (CD) (35). Patients of both groups were referred to the rheumatology clinic for rheumatic manifestations that require antiinflammatory therapy and were intolerable to the t-NSAIDs. The level of the IBD activity at the baseline visit, when drug/placebo therapy was initiated, was scored for all subjects included in the study. In the study group the dose of etoricoxib ranged from 60 to 120 mg tablet once a day according to their rheumatic condition. The control group received a placebo tablet once a day. Adverse events related to the use of the study medication in 1 and 3 months time were documented. Etoricoxib/placebo therapy was stopped once the patient experience flare up of their IBD.

RESULTS

There was no significant difference between the patients and the control groups. After 3 months of etoricoxib therapy, 8 of 76 (10.53%) of the study group had aggravation of their underlying IBD and stopped the drug therapy, while 68 of 76 (89.5%) completed the study. The mean disease activity index before etoricoxib therapy was 1.15 + 0.794, whereas it was 1.19 + 0.683 after therapy. In the control group 8 of 70 (11.43%) experienced exacerbation of their symptoms while 62 of 70 (88.6%) completed the study. In the control group the mean disease activity before treatment was 1.16 + 0.253, whereas after placebo therapy was 1.20 + 0.481. 67 of 76 (88.2%) of the study group and 62 of 70 (88.6%) of the control group gave history of using t-NSAID therapy in addition to PPI that caused flare up of their IBD. For the patients who had to stop their drug therapy, all the adverse events occurred in the first month of drug/placebo challenge and all symptoms were reversible.

CONCLUSION

Etoricoxib therapy is safe and beneficial in most patients with IBD treatment with etoricoxib was not associated with exacerbation of the underlying IBD- and GI-related complications.

Nitric oxide releasing derivatives of tolfenamic acid with anti-inflammatory activity and safe gastrointestinal profile

Tolfenamic acid esters with nitrooxyalcohols are synthesized. They are anti-inflammatory agents reducing carrageenan rat paw edema, with low gastrointestinal and general toxicity. In vitro, they are nitric oxide donors, inhibitors of lipoxygenase and cyclooxygenases. A two to three carbon chain between carboxylic and nitric ester groups seems optimal for activity.

COX-dependent mechanisms involved in the antinociceptive action of NSAIDs at central and peripheral sites

Despite the diverse chemical structure of aspirin-like drugs, the antinociceptive effect of NSAIDs is mainly due to their common property of inhibiting cyclooxygenases involved in the formation of prostaglandins. Prostaglandins are potent hyperalgesic mediators which modulate multiple sites along the nociceptive pathway and enhance both transduction (peripheral sensitizing effect) and transmission (central sensitizing effect) of nociceptive information. Inhibition of the formation of prostaglandins at peripheral and central sites by NSAIDs thus leads to the normalisation of the increased pain threshold associated with inflammation. The contribution of peripheral and central mechanisms to the overall antinociceptive action of NSAIDs depends on several factors including the location of the targets of drug action, the site of drug delivery and the uptake and distribution to the site of action. The present work reviews the data on the regulation and location of cyclooxygenases at central and peripheral sites of the nociceptive pathway and focuses on the role of COX in the generation and maintenance of pain hypersensitivity. Experimental and clinical evidences are used to evaluate the significance of the peripheral and central antihyperalgesic effects of NSAIDs.

The effects of selective cyclooxygenase-2 inhibitors, celecoxib and rofecoxib, on experimental colitis induced by acetic acid in rats

Several mediators may be involved in the pathogenesis of inflammatory bowel disease, as well as in experimental colitis. The present work was conducted to investigate the effects of the two selective cyclooxygenase-2 inhibitors, celecoxib and rofecoxib, on experimentally induced colitis in rats. Rectal instillation of acetic acid was used to induce the colitis. Acetic acid treatment caused haemorrhagic diarrhoea and weight loss in rats. Celecoxib (5 mg/kg) or rofecoxib (2.5 mg/kg), when given twice daily by the oral route, reduced the degree of haemorrhagic diarrhoea and the weight loss produced. In addition, they produced a significant reduction in the degree of colonic injury, the rise in myeloperoxidase (MPO) levels, total nitric oxide synthetase (NOS) activity, platelet-activating factor (PAF), histamine levels and prostaglandin E2 levels. In contrast, there was a significant increase in the levels of reduced glutathione (GSH). Thus, the findings of the present study provide evidence that selective cyclooxygenase-2 inhibitors may be beneficial in patients with inflammatory bowel disease.

Prostanoids and prostanoid receptors in signal transduction

Prostanoids are arachidonic acid metabolites and are generally accepted to play pivotal functions in amongst others inflammation, platelet aggregation, and vasoconstriction/relaxation. Inhibition of their production with, for instance, aspirin has been used for over a century to combat a large variety of pathophysiological processes, with great clinical success. Hence, the cellular changes induced by prostanoids have been subject to an intensive research effort and especially prostanoid-dependent signal transduction has been extensively studied. In this review, we discuss the impact of the five basic prostanoids, TxA(2), PGF(2alpha), PGE(2), PGI(2), and PGD(2), via their receptors on cellular physiology. These inflammatory lipids may stimulate serpentine plasma membrane-localized receptors, which in turn affect major signaling pathways, such as the MAP kinase pathway and the protein kinase A pathway, finally resulting in altered cellular physiology. In addition, prostanoids may activate the PPARgamma members of the steroid/thyroid family of nuclear hormone receptors, which act as transcription factors and may thus directly influence gene transcription. Finally, evidence exists that prostanoids act as second messengers downstream of mitogen receptor activation, mediating events, such as cytoskeletal changes, maybe via direct interaction with GTPase activating proteins. The final cellular reaction to prostaglandin stimulation will most likely depend on combined effects of the above-mentioned levels of interaction between prostaglandins and their cellular receptors.

Vascular Aging: Molecular Modulation of the Prostanoid Cascade by Calorie Restriction

The relevance of prostanoids to inflammation, thrombosis, and cardiovascular diseases is well known. The present study attempts to explore age effects on prostanoids and their biosynthesis cascade. Results from comparing prostanoid levels between young (6 months) and old (24 months) Fischer 344 rats showed rises of prostaglandin E2 (PGE2), PGI2, and thromboxane A2 (TXA2) levels in the old rats. Correlating evidence showed gene expression up-regulation of several prostanoid synthase enzymes in old rat aorta. Further, we found that expression of the antioxidant enzyme glutathione peroxidase was raised by age in the aorta, while superoxide dismutase and catalase expression showed no significant change during aging in the aorta. Moreover, calorie restriction (CR) was found to attenuate age-related prostanoid changes by suppressing inflammatory activities. In conclusion, the data from this study indicated that age-related increases in prostanoids and their biosynthesis might be closely associated with a weakened antioxidant capacity.

ABT-963 [2-(3,4-Difluoro-phenyl)-4-(3-hydroxy-3-methyl-butoxy)-5-(4-methanesulfonyl-phenyl)-2H-pyridazin-3-one], A Highly Potent and Selective Disubstituted Pyridazinone Cyclooxgenase-2 Inhibitor

Nonsteriodal anti-inflammatory drugs (NSAIDs) are efficacious for the treatment of pain associated with inflammatory disease. Clinical experience with marketed selective cyclooxygenase-2 (COX-2) inhibitors (celecoxib, rofecoxib, and valdecoxib) has confirmed the utility of these agents in the treatment of inflammatory pain with an improved gastrointestinal safety profile relative to NSAID comparators. These COX-2 inhibitors belong to the same structural class. Each contains a core heterocyclic ring with two appropriately substituted phenyl rings appended to adjacent atoms. Here, we report the identification of vicinally disubstituted pyridazinones as potent and selective COX-2 inhibitors. The lead compound in the series, ABT-963 [2-(3,4-difluoro-phenyl)-4-(3-hydroxy-3-methyl-butoxy)-5-(4-methanesulfonyl-phenyl)-2H-pyridazin-3-one], has excellent selectivity (ratio of 276, COX-2/COX-1) in human whole blood, improved aqueous solubility compared with celecoxib and rofecoxib, high oral anti-inflammatory potency in vivo, and gastric safety in the animal studies. After oral administration, ABT-963 reduced prostaglandin E2 production in the rat carrageenan air pouch model (ED50 of 0.4 mg/kg) and reduced the edema in the carrageenan induced paw edema model with an ED30 of 1.9 mg/kg. ABT-963 dose dependently reduced nociception in the carrageenan hyperalgesia model (ED50 of 3.1 mg/kg). After 14 days of dosing in the adjuvant arthritis model, ABT-963 had an ED(50) of 1.0 mg/kg in reducing the swelling of the hind paws. Magnetic resonance imaging examination of the diseased paws in the adjuvant model showed that ABT-963 significantly reduced bone loss and soft tissue destruction. ABT-963 is a highly selective COX-2 inhibitor that may have utility in the treatment of the pain and inflammation associated with arthritis.

Methanesulfonamide group at position-4 of the C-5-phenyl ring of 1,5-diarylpyrazole affords a potent class of cyclooxygenase-2 (COX-2) inhibitors

The effect of methanesulfonamide (MeSO(2)NH) group on COX-2 inhibitory activity of 1,5-diarylpyrazole is described. While this group being at position-4 of the N(1)-phenyl ring was found to be ineffective, its installation at position-4 of the C-5 phenyl ring offered several potent and selective inhibitors of COX-2 with IC(50) as low as 30 nM.

[Pharmacology and classification of cyclooxygenase inhibitors]

The discovery of at least two cyclooxygenase (COX) isoenzymes had two major consequences: i) to give a new impetus to the research on lipid metabolism, giving rise to the crystallization of these peculiar membrane enzymes, the characterization of their active sites and their gene regulation, and the identification of new metabolic pathways; ii) the development of new NSAIDs aimed to have an improved safety profile, the coxibs. These drugs are defined by their COX-2 selectivity which is supported by a negligible inhibitory potency on platelet COX-1 in vitro and ex vivo after oral intake of maximal therapeutic doses. However, the coxibs marketed in France (celecoxib, rofecoxib, parecoxib) are not equivalent in terms of selectivity and some drugs developed by pharmaceutical companies (etoricoxib, lumiracoxib) will be even more selective for COX-2. These "new" coxibs are the final step in the theory of COX-2 selectivity and they will probably be helpful to better define the limitations of the therapeutic concept based on a selective inhibition of this iso-enzyme.

In vitro investigation of the effects of nonsteroidal anti-inflammatory drugs, prostaglandin E2, and prostaglandin F2alpha on contractile activity of the third compartment of the stomach of llamas

OBJECTIVE

To determine the in vitro effect of prostaglandin (PG) E2, PGF2alpha, and the nonsteroidal anti-inflammatory drugs (NSAIDs) indomethacin, ketoprofen, and nabumetone on the contractile strength of the circular smooth muscle layer of the third compartment of the stomach of llamas.

SAMPLE POPULATION

Specimens of the third compartment obtained from 5 healthy adult llamas.

PROCEDURE

Full-thickness tissue samples were collected from the third compartment immediately after euthanasia. Specimens were cut into strips oriented along the circular muscle layer and mounted in a tissue bath system. Incremental amounts of ketoprofen, nabumetone, indomethacin, PGE2, and PGF2alpha were added, and contractile strength (amplitude of contractions) was recorded.

RESULTS

Generally, PGE2 reduced contractile strength of the circular smooth layer of the third compartment, whereas PGF2alpha, increased the strength of contractions. The activity of the NSAIDs was generally excitatory in a concentration-dependent manner, although significant changes were induced only by administration of indomethacin.

CONCLUSIONS AND CLINICAL RELEVANCE

On isolated smooth muscle strips of the third compartment of llamas, exogenous PGE2 and PGF2alpha had a variable effect on contractile strength. Administration of the NSAIDs did not inhibit contractility and would not be likely to induce stasis of the third compartment in the absence of an underlying disease process.

Effect of Aspirin and Indomethacin on Prostaglandin E2 Synthesis in C6 Glioma Cells

Prostaglandin E2 (PGE2) plays an important role in immunosuppression and tumor growth. PGE2 inhibitors such as aspirin and indomethacin suppress experimental tumor growth. Little is known of the relationship between PGE2 synthesis in brain tumors and the dose of aspirin or indomethacin. The present study was undertaken to evaluate the effect of different doses of aspirin and indomethacin on PGE2 synthesis in C6 glioma cells. C6 glioma cells were incubated with different concentrations (2, 4, and 8 microM) of aspirin and indomethacin for 1, 2, 4, 6, 8, 12, and 24 hours. Intracellular PGE2 concentration was measured by enzyme immunoassay. Each concentration of aspirin and indomethacin effectively inhibited PGE2 synthesis. Concentrations of 2, 4, and 8 microM of aspirin significantly inhibited PGE2 production at 6, 4, and 1 hour, respectively, and the inhibition persisted for more than 24 hours (p < 0.05). Concentrations of 2 and 4 microM of indomethacin were effective at 4 and 2 hours (p < 0.05), respectively. However, inhibition was not observed beyond 12 hours (p > 0.05). Indomethacin 8 microM was effective at 1 hour and the inhibition persisted beyond 24 hours (p < 0.05). Our study demonstrates that aspirin and indomethacin inhibit PGE2 synthesis in C6 glioma cells and that low-dose aspirin is as effective as high-dose aspirin. This study may encourage future clinical use of low-dose aspirin in the prevention or treatment of brain tumors.

Cyclooxygenase isozymes involved in adaptive functional responses in rat stomach after barrier disruption

We investigated the preferential role of cyclooxygenase (COX) isozymes in various functional changes of the rat stomach after exposure to taurocholate (TC) as a mild irritant. Under urethane anesthesia, a rat stomach mounted in an ex vivo chamber was perfused with saline or acid (50 mM HCl), and transmucosal potential difference (PD), gastric mucosal blood flow (GMBF), and acid secretion were measured before and after exposure of the stomach to 20 mM TC for 30 min. Indomethacin, 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazole (SC-560) (a selective COX-1 inhibitor), or rofecoxib (a selective COX-2 inhibitor) was given intraduodenally 30 min before the TC treatment. Mucosal application of TC caused a marked reduction in PD, followed by a decrease of acid secretion and an increase of GMBF. Previous administration of indomethacin did not affect the reduction in PD but significantly mitigated the two other responses induced by TC, resulting in a delay in the recovery in PD. These effects were mimicked by SC-560 but not rofecoxib, although neither of these drugs had any effect on the reduction in PD. Perfusion of TC-treated stomachs with 50 mM HCl caused only minimal damage, yet this treatment produced gross lesions in the presence of indomethacin or SC-560. Mucosal exposure to TC increased prostaglandin E2 production, but the response was inhibited by both indomethacin and SC-560 but not rofecoxib. These results suggested that COX-1 but not COX-2 is a key enzyme for regulating the functional alterations of the stomach and for maintaining the mucosal integrity after barrier disruption.