Antinociceptive properties of esculetin in non‐inflammatory and inflammatory models of pain in rats

Some studies suggest that 5‐lipoxygenase (5‐LOX) inhibition or leukotriene receptor antagonism may effectively attenuate different kinds of pain. In the present study, we investigated whether esculetin (which, among other actions, potently inhibits 5‐LOX) possesses analgesic activity in acute non‐inflammatory pain and acute inflammatory pain models in rats. We also examined the effects of zileuton, a selective 5‐LOX inhibitor, on esculetin activity. Plasma concentrations of leukotriene B₄ (LTB₄) after administration of esculetin were also determined. Esculetin (1.25–20 mg/kg, i.p.) dose‐dependently alleviated hyperalgesia and exhibited antinociceptive effects in both experimental models. The greatest effect of esculetin was observed with a dose of 20 mg/kg. In carrageenan‐induced inflammatory pain in rats, 20 mg/kg esculetin reversed or mitigated hyperalgesia, increasing the threshold to mechanical stimuli from a control value of ?23.8 ± 1.8% to 15.2 ± 2.2% (P < 0.01) and that to thermal stimuli from ?52.5 ± 6.1% to ?9.5 ± 3.9% (P < 0.01). In non‐inflammatory pain, after esculetin (20 mg/kg) administration the threshold values to mechanical and thermal stimuli increased to 75.9 ± 4.2% and 59.2 ± 4.3%, respectively (P < 0.01 for both). Zileuton (30 mg/kg, p.o.) alone slightly but significantly increased the pain threshold in the non‐inflammatory and inflammatory acute pain models. Pretreatment with 30 mg/kg, p.o., zileuton significantly enhanced the analgesic activity of 5 mg/kg, i.p., esculetin in both pain models. Moreover, esculetin (10 mg/kg, i.p.) decreased LTB₄ concentrations in the blood from 244 ± 29 pg/mL in the control group to 185 ± 11 pg/mL (P < 0.005). The results of the present study suggest the involvement of the 5‐LOX pathway in esculetin analgesia.     

Antinociceptive,anti-inflammatory and antipyretic properties of an aqueous extract of Corchorus capsularis leaves in experimental animal models

The present study was carried out to establish the antinociceptive, anti-inflammatory and antipyretic properties of an aqueous extract of jute plant leaves, Corchorus capsularis L. (Tiliaceae), in experimental animals. The antinociceptive activity was measured using the abdominal constriction, hot plate and formalin tests, while the anti-inflammatory and antipyretic activities were measured using the carrageenan-induced paw edema and brewer’s yeast-induced pyrexia tests, respectively. The extract, obtained after 72 h soaking of the air-dried leaves in distilled water, freeze-drying for 72 h and then prepared in dosages of 11.57, 57.85, and 115.7 mg/kg, was administered subcutaneously (10 ml/kg) 30 min prior to subjection to the above mentioned assays. The extract was found to exhibit significant (antinociceptive, anti-inflammatory and anti-pyretic, activities in a dosage-independent manner. In conclusion, the aqueous extract of C. capsularis possesses antinociceptive and antipyretic activities and supports the previous claim of its traditional use to treat various ailments.     

Hypoxia inducible factor‐1α inhibition produced anti‐allodynia effect and suppressed inflammatory cytokine production in early stage of mouse complex regional pain syndrome model

Complex regional pain syndrome (CRPS) is related to microcirculation impairment associated with tissue hypoxia and peripheral cytokine overproduction in the affected limb. Previous studies suggest that the pathogenesis involves hypoxia inducible factor‐1α (HIF‐1α) and exaggerated regional inflammatory response. 1‐methylpropyl 2‐imidazolyl disulfide (PX‐12) acts as the thioredoxin‐1 (Trx‐1) inhibitor and decreases the level of HIF‐1α, and can rapidly be metabolized for Trx‐1 redox inactivation. This study hypothesized that PX‐12 can decrease the cytokine production for nociceptive sensitization in the hypoxia‐induced pain model. CD1 mice weighing around 30 g were used. The animal CRPS model was developed via the chronic post‐ischaemic pain (CPIP) model. The model was induced by using O‐rings on the ankles of the mice hind limbs to produce 3‐h ischaemia–reperfusion injury on the paw. PX‐12 (25 mg/kg, 5 mg/kg) was given through tail vein injection immediately after ischaemia. Animal behaviour was tested using the von Frey method for 7 days. Local paw skin tissue was harvest from three groups (control, 5 mg/kg, 25 mg/kg) 2 h after injection of PX‐12. The protein expression of interleukin‐1β (IL‐1β) and HIF‐1α was analysed with the Western blotting method. Mice significantly present an anti‐allodynia effect in a dose‐related manner after the PX‐12 administration. Furthermore, PX‐12 not only decreased the expression of HIF‐1α but also decreased the expression of IL‐1β over the injured palm. This study, therefore, shows the first evidence of the anti‐allodynia effect of PX‐12 in a CPIP animal model for pain behaviour. The study concluded that inhibition of HIF‐1α may produce an analgesic effect and the associated suppression of inflammatory cytokine IL‐1β in a CPIP model.     

Investigation of anti‐inflammatory,nitric oxide donating,vasorelaxation and ulcerogenic activities of 1, 3‐diphenylprop‐2‐en‐1‐one derivatives in animal models

The main aim of this work is to find out novel chemical moieties with potent anti‐inflammatory and vasorelaxant activities with reduced gastric toxicities. For fulfilling the above aim, here we investigated novel chalcones (1, 3‐diphenylprop‐2‐en‐1‐one derivatives) with nitric oxide (NO) and hydrogen sulphide (H₂S) donating potency for anti‐inflammatory activity by carrageenan‐induced rat paw oedema. These molecules then further evaluated for in‐vitro NO‐releasing potency and vasorelaxation effect on isolated adult goat aortic tissue. The promising molecules were further screened for ulcerogenic activity in the rat model. The tested compounds produced % inhibition in paw oedema ranging from 29.16% to 79.69% and standard drug Diclofenac sodium produced 85.30% reduction in paw oedema after 5 hours. Out of this dataset, compounds AI1, AI7, Ca1, B2, B10, D2, and E8 showed 73.01%, 79.69%, 75.02%, 75.46%, 74.35%, 73.9% and 74.35% reduction in paw oedema respectively, which is approximately 80%–90% to that of standard Diclofenac sodium. The compound Ca1 was found to release 0.870 ± 0.025 mol/mol of NO and standard Glyceryl trinitrate (GTN) was found to release 0.983 ± 0.063 mol/mol of NO. The compound Ca1 produced 950.2 μmol/L of EC₅₀ whereas standard GTN produced 975.8 μmol/L of EC₅₀ for aortic smooth relaxation. The compounds Ca1 produced 0.1117 of ulcer index which is far less than that of standard Diclofenac sodium (1.148). The potent lead molecules were further evaluated to understand the mechanism of vasorelaxation by using specific antagonists or blockers of NO and H₂S.     

Curcumin‐loaded poly(ε‐caprolactone) nanofibres: Diabetic wound dressing with anti‐oxidant and anti‐inflammatory properties

• 1 Curcumin is a naturally occurring poly‐phenolic compound with a broad range of favourable biological functions, including anti‐cancer, anti‐oxidant and anti‐inflammatory activities. The low bioavailability and in vivo stability of curcumin require the development of suitable carrier vehicles to deliver the molecule in a sustained manner at therapeutic levels.
• 2 In the present study, we investigated the feasibility and potential of poly(caprolactone) (PCL) nanofibres as a delivery vehicle for curcumin for wound healing applications. By optimizing the electrospinning parameters, bead‐free curcumin‐loaded PCL nanofibres were developed.
• 3 The fibres showed sustained release of curcumin for 72 h and could be made to deliver a dose much lower than the reported cytotoxic concentration while remaining bioactive. Human foreskin fibroblast cells (HFF‐1) showed more than 70% viability on curcumin‐loaded nanofibres.
• 4 The anti‐oxidant activity of curcumin‐loaded nanofibres was demonstrated using an oxygen radical absorbance capacity (ORAC) assay and by the ability of the fibres to maintain the viability of HFF‐1 cells under conditions of oxidative stress.
• 5 The curcumin‐loaded nanofibres also reduced inflammatory induction, as evidenced by low levels of interleukin‐6 release from mouse monocyte–macrophages seeded onto the fibres following stimulation by Escherichia coli‐derived lipopolysaccharide.
• 6 The in vivo wound healing capability of the curcumin loaded PCL nanofibres was demonstrated by an increased rate of wound closure in a streptozotocin‐induced diabetic mice model.
• 7 These results demonstrate that the curcumin‐loaded PCL nanofibre matrix is bioactive and has potential as a wound dressing with anti‐oxidant and anti‐inflammatory properties.

     

Mechanisms involved in the antinociceptive and anti‐inflammatory effects of bis selenide in mice

Objectives The present study examined the mechanisms involved in the antinociceptive effects of bis selenide [(Z)‐2,3‐bis(4‐chlorophenylselanyl)prop‐2‐en‐1‐ol]. Methods The effects of oral bis selenide were tested against licking behaviour and oedema in mice induced by formalin, serotonin, histamine, glutamate, phorbol 12‐myristate 13‐acetate (PMA), 8‐bromoadenosine 3′,5′‐cyclic monophosphate (8‐BrcAMP) and pros‐taglandin E₂. The effects of a variety of receptor antagonists on the antinociceptive activity were tested to determine the likely mechanism of action of bis selenide. Key findings Bis selenide caused antinociception on the first and second phases of the formalin test, with mean ID50 values of 34.21 (29.66–39.45) and 15.86 (12.17–20.67) mg/kg and maximal inhibition of 65 ± 3% and 90 ± 1%, respectively. At 50 mg/kg bis selenide significantly inhibited (31 ± 2%) paw oedema induced by intraplantar injection of formalin. At 25 mg/kg given 5 min after the formalin injection, bis selenide caused a significant inhibition (42 ± 5%) in the second phase of the formalin test, whereas the prophylactic treatment caused more intense inhibition (64 ± 3%). Oral administration of bis selenide reduced licking and paw oedema induced by serotonin, histamine, glutamate, PGE₂, PMA and 8‐BrcAMP. The antinociceptive effect of bis selenide (25 mg/kg, p.o.) on the formalin test was reversed by i.p. administration of p‐chlorophenylalanine methyl ester (an inhibitor of serotonin synthesis), ketanserin (a selective 5‐HT_2a receptor antagonist), ondansetron (a 5‐HT₃ receptor antagonist) and ranitidine (a histamine H₂‐receptor antagonist). Conclusions Glutamatergic, prostaglandin E₂, serotonergic (5‐HT_2a and 5‐HT₃) and histamine H₂ receptors are involved in the antinociceptive effects of bis selenide in mice. The interaction of bis selenide with protein kinase C and A signalling pathways was also demonstrated.     

Synthesis,anticancer activity and cytotoxicity of 7‐O‐β‐d‐galactosyl‐polyethylene glycol‐epothilone B

Epothilone, the macrolide compound produced by Sorangium cellulosum, has antitumor activity. Its anti‐tumor mechanism is similar to that of paclitaxel, which promotes the polymerization of tubulin and induces apoptosis. Herein, 7‐O‐β‐d ‐galactosyl‐polyethylene glycol‐epothilone B 6 was synthesized. It showed that the toxicity of the synthesized compound was 1/182 of the epothilone B. In addition, compound 6 also had significant anticancer activity under the action of enzyme.     

Synthesis of new carbon‐11‐labeled 7‐aroyl‐aminoindoline‐1‐sulfonamides as potential PET agents for imaging of tubulin polymerization in cancers

The tubulin polymerization is an attractive target for anticancer therapy and in the development of cancer imaging agents for use in biomedical imaging technique positron emission tomography (PET). 7‐Aroyl‐aminoindoline‐1‐sulfonamides are a novel class of potent antitublin agents. Carbon‐11‐labeled 7‐aroyl‐aminoindoline‐1‐sulfonamides have been synthesized as new potential PET agents for imaging of tubulin polymerization in cancers. The target tracers were prepared by O‐[¹¹C]methylation of their corresponding precursors using [¹¹C]CH₃OTf and isolated by a simplified solid‐phase extraction purification procedure in 40–55% radiochemical yields based on [¹¹C]CO₂ and decay corrected to the end of bombardment (EOB), 15–20 min overall synthesis time from EOB, >98% radiochemical purity, and 74–111 GBq/µmol specific activity at the end of synthesis. Copyright © 2008 John Wiley & Sons, Ltd.     

Evaluation of anti‐angiogenic,anti‐inflammatory and antinociceptive activity of coenzyme Q10 in experimental animals

Objectives This work aimed to assess some pharmacological activities of coenzyme Q₁₀ (CoQ₁₀) in animal experimental models. Methods The chick chorioallantoic membrane assay was used to evaluate anti‐angiogenic activity of CoQ₁₀. Anti‐inflammatory activity of CoQ₁₀ was confirmed using two animal models of inflammation. These were the vascular permeability and air pouch models, models of acute and sub‐acute inflammation, respectively. Antinociceptive activity was assessed by the acetic acid‐induced abdominal constriction response. Key findings CoQ₁₀ dose‐dependently displayed inhibition of chick chorioallantoic membrane angiogenesis. In the acetic acid‐induced vascular permeability model in mice, CoQ₁₀ at 50, 100 and 200 mg/kg reduced vascular permeability from 0.74 ± 0.01 (A₅₉₀) to 0.67 ± 0.01 (P < 0.01), 0.46 ± 0.02 (P < 0.01) and 0.30 ± 0.01 (P < 0.01), respectively. In the carrageenan‐induced inflammation in the air pouch, CoQ₁₀ was able to diminish exudate volume, the number of polymorphonulcear leucocytes and nitrite content in the air pouches. CoQ₁₀ at 25, 50 and 100 mg/kg significantly reduced acetic acid‐induced abdominal constriction in mice from 27.0 ± 2.00 (number of abdominal constrictions) to 17.7 ± 0.33 (P < 0.01), 9.3 ± 0.67 (P < 0.01) and 1.3 ± 0.33 (P < 0.01), respectively, suggesting a strong antinociceptive activity. Conclusions CoQ₁₀ possessed considerable anti‐angiogenic, anti‐inflammatory and antinociceptive activity, possibly via down‐regulating the level of nitric oxide, which partly supported its use as a dietary supplement and in combination therapy.     

In vitro evaluation of the effects of anti‐fungals,benzodiazepines and non‐steroidal anti‐inflammatory drugs on the glucuronidation of 19‐norandrosterone: implications on doping control analysis

We have studied whether the phase II metabolism of 19‐norandrosterone, the most representative metabolite of 19‐nortestosterone (nandrolone), can be altered in the presence of other drugs that are not presently included on the Prohibited List of the World Anti‐Doping Agency. In detail, we have evaluated the effect of non‐prohibited drugs belonging to the classes of anti‐fungals, benzodiazepines, and non‐steroidal anti‐inflammatory drugs on the glucuronidation of 19‐norandrosterone. In vitro assays based on the use of either pooled human liver microsomes or specific recombinant isoforms of uridine diphosphoglucuronosyl‐transferase were designed and performed to monitor the formation of 19‐norandrosterone glucuronide from 19‐norandrosterone. Determination of 19‐norandrosterone (free and conjugated fraction) was performed by gas chromatography – mass spectrometry after sample pretreatment consisting of an enzymatic hydrolysis (performed only for the conjugated fraction), liquid/liquid extraction with tert‐butylmethyl ether, and derivatization to form the trimethylsilyl derivative. In parallel, a method based on reversed‐phase liquid chromatography coupled to tandem mass spectrometry in positive electrospray ionization with acquisition in selected reaction monitoring mode was also developed to identify the non‐prohibited drugs considered in this study. Incubation experiments have preliminarily shown that the glucuronidation of 19‐norandrosterone is principally carried out by UGT2B7 (39%) and UGT2B17 (31%). Inhibition studies have shown that the yield of the glucuronidation reaction is reduced in the presence of the anti‐fungals itraconazole, ketoconazole, and miconazole, of the benzodiazepine triazolam and of the non‐steroidal anti‐inflammatory drugs diclofenac and ibuprofen, while no alteration was recorded in the presence of all other compounds considered in this study. Copyright © 2015 John Wiley & Sons, Ltd.     

Design and syntheses of methyl 2‐methyl‐2‐[2‐(4‐benzoyl‐5‐phenyl‐7‐halo‐2‐azabicyclo[4.1.0]hept‐3‐ene)]acetates: novel inhibitors of cyclooxygenase‐2 (COX‐2) with analgesic‐antiinflammatory activity

A group of methyl 2‐methyl‐2‐[2‐(4‐benzoyl‐5‐phenyl‐7‐halo‐2‐azabicyclo[4.1.0]hept‐3‐ene)]acetates ( 10–15 ), and the related acetamide derivative ( 16 ), that possess a variety of C‐7 substituents (Br, Cl, F, H), were designed for evaluation as analgesic‐antiinflammatory agents. The effect of the C‐7 substituent(s) and the nature of the acetic acid ester (R¹ = Ome) or acetamide (R¹ = NH₂) moiety on analgesic activity was determined using a 4% NaCl‐induced abdominal constriction assay. Compounds 10–16 inhibited writhing by 36–82%, relative to the reference drugs aspirin (58% inhibition) and celecoxib (62% inhibition). The nature of the C‐7 substituents was a determinant of analgesic activity in the 7,7‐dihalo group of compounds where the relative activity profile was 7‐Cl₂ > 7‐Br₂ > 7‐F₂ > 7‐Cl,7‐F, and for 7‐monohalo compounds where the potency order was 7‐Br > 7‐Cl. Elaboration of the 7,7‐dibromo methyl acetate ester ( 10 ) to the corresponding acetamide derivative ( 16 ) enhanced analgesic activity. The nature of the 7‐halo substituent(s) in the 7,7‐dihalo group of compounds was a determinant of antiinflammatory activity, determined using the carrageenan‐induced rat paw edema assay, where the relative potency order was 7‐Br₂ > 7‐Cl₂ > 7‐F₂ > 7‐Cl,7‐F. The most potent 7,7‐dibromo compound ( 10 ) inhibited inflammation by 62%, relative to the reference drug ibuprofen (44%), and 10 inhibited COX‐2 (IC₅₀ = 26.4 μM) and COX‐1 (IC₅₀ = 227 μM) for a COX‐2 selectivity index of 8.6. Docking 10 in the active site of human COX‐2 showed it binds in the center of the COX‐2 binding site with the C‐5 phenyl ring oriented toward the acetylation site (Ser⁵³⁰), and the phenyl group of the C‐4 benzoyl moiety oriented in the vicinity of the COX‐2 secondary binding pocket near Val⁵²³. Drug Dev. Res. 49:75–84, 2000. © 2000 Wiley‐Liss, Inc.     

7‐Chloro‐4‐quinolinyl Hydrazones: A Promising and Potent Class of Antileishmanial Compounds

In this work, we report the antileishmanial evaluation of twenty 7‐chloro‐4‐quinolinyl hydrazone derivatives ( 1 – 20 ). Firstly, the compounds were tested against promastigotes of four different Leishmania species. After that, all derivatives were assayed against L. braziliensis amastigotes and murine macrophages. Furthermore, it was investigated whether the antiamastigote L. braziliensis effect of the compounds could be associated with nitric oxide production. Compounds 6 and 7 showed a strong leishmanicidal activity against intracellular parasite with IC₅₀ in nanogram levels (30 and 20 ng/mL, respectively). Appreciable activity of three compounds tested can be considered an important finding for the rational design of new leads for antileishmanial compounds.     

Angiotensin‐(1‐7)‐mediated Mas1 receptor/NF‐κB‐p65 signaling is involved in a cigarette smoke‐induced chronic obstructive pulmonary disease mouse model

Angiotensin‐(1‐7) [Ang‐(1‐7)] has been shown to play a significant role in the pathogenesis of lung inflammation via Mas receptor; however, its effect in chronic obstructive pulmonary disease (COPD) remains unknown. To explore the effect of Ang‐(1‐7) on a cigarette smoke (CS) exposure‐induced COPD model, 40 C57BL/6J mice were divided into four groups (n = 10) and exposed to air or CS for 8 weeks. After that, they were treated with saline or Ang‐(1‐7) at 0.3 mg/kg for 2 weeks by subcutaneous infusion using osmotic pump. The day following drug/vehicle challenge, lung function was examined and bronchoalveolar lavage (BAL) was performed. Chemokine (C–X–C motif) ligand 1, interleukin‐6, and tumor necrosis factor‐α protein levels in BAL fluid were determined using ELISA; the corresponding mRNA levels in lung tissues were measured using RT‐PCR. Mas1 receptor, pIκBα, IκBα, nuclear NF‐κB‐p65 protein, pERK1/2, ERK2, pp38, and p38 proteins expression in lung tissues were examined by immunohistochemical staining and western blotting. Ang‐(1‐7) challenge had no effect on the decreased lung function and emphysema induced by CS exposure. However, Ang‐(1‐7) treatment blocked CS exposure‐induced lung inflammatory responses and lung fibrosis, as determined by Masson's Trichrome staining. Exposure to CS for 8 weeks caused irreversible loss of lung function and emphysema, which could not be reversed by Ang‐(1‐7) treatment. Thus, the beneficial effect of Ang‐(1‐7) may be confined to pulmonary inflammation and fibrosis.     

Ambroxol, a Nav1.8-preferring Na(+) channel blocker, effectively suppresses pain symptoms in animal models of chronic, neuropathic and inflammatory pain

Neuropathic pain affects many patients, and treatment today is far from being perfect. Nav1.8 Na⁺ channels, which are expressed by small fibre sensory neurons, are promising targets for novel analgesics. Na⁺ channel blockers used today, however, show only limited selectivity for this channel subtype, and can cause dose-limiting side effects. Recently, the secretolytic ambroxol was found to preferentially inhibit Nav1.8 channels. We used this compound as a tool to investigate whether a Nav1.8-preferring blocker can suppress symptoms of chronic, neuropathic and inflammatory pain in animal models. The drug was tested in the formalin paw model, two models of mononeuropathy, and a model of monoarthritis in rats. Ambroxol's effects were compared with those of gabapentin. Ambroxol at a dose of 1 g/kg had to be administered to rats to achieve the plasma levels that are reached in clinical use (for the treatment of infant and acute respiratory distress syndrome). Ambroxol (1 g/kg) was only weakly effective in models for acute pain, but effectively reduced pain symptoms in all other models; in some cases it completely reversed pain behaviour. In most cases the effects were more pronounced than those of gabapentin (at 100 mg/kg). These data show that a Nav1.8-preferring Na⁺ channel blocker can effectively suppress pain symptoms in a variety of models for chronic, neuropathic and inflammatory pain at plasma levels, which can be achieved in the clinic.