Recent progress on anti-nociceptive effects of carbon monoxide releasing molecule-2 (CORM-2)

The role of carbon monoxide (CO) has evolved albeit controversial disputes on its toxicity. This biological gasotransmitter participates in the endogenous regulation of neurotransmitters and neuropeptides released in the nervous system. Exogenous CO gas inhalation at a lower concentration has been the subject of investigations, which have revealed its biological homeostatic mechanisms and protective effects against many pathological conditions. This therapeutic procedure of CO is, however, limited due to its immediate release, which favours haemoglobin at a high affinity with the subsequent generation of toxic carboxyhaemoglobin in tissues. In order to address this problem, carbon monoxide releasing molecule-2 (CORM-2) or also known as tricarbonyldichlororuthenium II dimer is developed to liberate a controlled amount of CO in the biological systems. In this review, we examine several potential mechanisms exerted by this therapeutic compound to produce the anti-nociceptive effect that has been demonstrated in previous studies. This review could shed light on the role of CORM-2 to reduce pain, especially in cases of chronic and neuropathic pain.

Blocking the major inflammatory pathways by newly synthesized thiadiazine derivatives via in-vivo, in-vitro and in-silico mechanism

A series of new thiadiazine derivatives including 2-(5-alkyl/aryl-6-thioxo-1,3,5-thiadiazinan-3-yl) propanoic acids (a) and 4-methyl-2-(5-alkyl/aryl-6-thioxo-1,3,5-thiadiazinan-3-yl) pentanoic acids (b) were synthesized by reacting primary alkyl/aryl amines with CS2, followed by reaction with formaldehyde and amino acids. The chemical structures of synthesized compounds were confirmed by 13C- NMR and 1H- NMR techniques. The inhibitory potential of major inflammatory enzymes, COX-2 and 5-LOX was examined. Moreover, anti-nociceptive and anti-inflammatory activities were evaluated in the in vivo thermally induced nociceptive, and carrageenan induced paw edema models in mice. The in-vitro results reflect that these compounds exhibited concentration dependent inhibition of COX-2 and 5-LOX. The tested compounds at 50 mg/kg showed significant effect on thermally induced pain, and reduced latency time (seconds) as compared to the vehicle treated animals. Moreover, tested compounds exhibited percent inhibition of paw edema in the carrageenan induced paw edema model in mice. Furthermore, the binding modes of the most active COX-2 and 5-LOX inhibitors were determined through computational methods. The computational study reflects that the docked compounds have high binding affinities for COX-2 and 5-LOX enzymes, which leads to inhibition of these enzymes.

Anti-inflammatory, anti-nociceptive and anti-pyretic activities of Cenchrus ciliaris L

ETHNOPHARMACOLOGICAL RELEVANCE

Cenchrus ciliaris L. belongs to the family Poaceae and is found all over the world. It is native to the Cholistan desert of Pakistan where it is locally known as 'Dhaman'. Owing to high nutritional value, C. ciliaris is used as fodder while seeds are used for bread making which are consumed by locals. It also possesses medicinal value and is extensively employed to treat pain, inflammation, urinary tract infection, and tumors.

AIM OF STUDY

Studies on the pharmacological activities of C. ciliaris are scarce in spite of its several traditional uses. To the best of our knowledge, no comprehensive study has been conducted on anti-inflammatory, analgesic and anti-pyretic activity of C. ciliaris until now. Here we employed an integrative phytochemical and in - vivo framework to evaluate the potential biological activities of C. ciliaris against inflammation, nociception and pyrexia experimentally induced in rodents.

MATERIAL AND METHODS

C. ciliaris was collected from the desert of Cholistan, Bahawalpur, Pakistan. Phytochemical profiling of C. ciliaris was done by employing GC-MS analysis. Anti-inflammatory activity of plant extract was initially determined by various in - vitro assays including albumin denaturation assay and RBC membrane stabilization assays. Finally, rodents were utilized to evaluate in - vivo anti-inflammatory, antipyretic and anti-nociceptive activities.

RESULTS

Our data revealed the presence of 67 phytochemicals in methanolic extract of C. ciliaris. The methanolic extract of C. ciliaris provided RBC membrane stabilization by 65.89 ± 0.32% and protection against albumin denaturation by 71.91 ± 3.42% at 1 mg/ml concentration. In in - vivo acute inflammatory models, C. ciliaris exhibited 70.33 ± 1.03, 62.09 ± 8.98, 70.24 ± 0.95% anti-inflammatory activity at concentration of 300 mg/ml against carrageenan, histamine and serotonin induced inflammation. In CFA induced arthritis, inhibition of inflammation was found to be 48.85 ± 5.11% at 300 mg/ml dose after 28 days of treatment. In anti-nociceptive assays C. ciliaris exhibited significant analgesic activity in both peripheral and centrally mediated pain. The C. ciliaris also reduced the temperature by 75.26 ± 1.41% in yeast induced pyrexia.

CONCLUSION

C. ciliaris exhibited anti-inflammatory effect against acute and chronic inflammation. It also showed significant anti-nociceptive and anti-pyretic activity which endorses its traditional use in the management of pain and inflammatory disorders.

Chemical composition and effects of ethanolic extract and gel of Cochlospermum regium (Schrank) Pilg. Leaves on inflammation, pain, and wounds

ETHNOPHARMACOLOGICAL RELEVANCE

Cochlospermum regium is well-known as "Algodãozinho do cerrado" in folk Brazilian medicine, and is used to fight infections, inflammation and skin disorders.

AIM OF THE STUDY

To identify the phytochemical constituents and the effects of the ethanolic extract of C. regium leaves (EECR) on inflammation and pain, and the effects of C. regium gel (GEECR) on wound healing.

MATERIALS AND METHODS

Animals were treated with EECR (30-300 mg/kg) or GEECR (1.25 and 2.5%) and studies were conducted using carrageenan-induced pleurisy and paw edema tests, formalin-induced pain model, and excision wound model.

RESULTS

In total, 25 compounds, including quercitrin, methyl gallate, and 1,2,3,4,6-pentagalloylhexose, with highest detectability were identified. The treatments reduced leukocyte migration, nitric oxide production, protein extravasation, edema, mechanical hyperalgesia, pain in both phases (neurogenic and inflammatory), cold hypersensitivity, and improved wound closure and tissue regeneration.

CONCLUSIONS

The present findings established the anti-inflammatory, anti-nociceptive, and wound healing potential of the leaves of C. regium, confirming the potential therapeutic effect of this plant.

Exploring the possible mechanism involved in the anti-nociceptive effect of β-sitosterol: modulation of oxidative stress, nitric oxide and IL-6

Β-sitosterol is a phytosterol, documented to possess various activities including protection against inflammation, diabetes and Alzheimer's disease. The current investigation was designed to explore the analgesic potential of β-sitosterol and the possible molecular mechanism involved in the observed effect. β-sitosterol was administered at varying doses of 10, 20, and 40 mg/kg before subjecting the mice to acetic acid and formalin challenges. The number of writhings in acetic acid and the number of flinchings and foot tappings were quantified in the formalin test. For mechanistic studies, substance P (cyclooxygenase-2 (COX-2) stimulator) and L-Nitro arginine methyl ester (L-NAME) (nitric oxide synthetases (NOS) inhibitor) and L-arginine (nitric oxide precursor) were administered before β-sitosterol treatment. β-sitosterol (10, 20, 40 mg/kg) treatment significantly reduced acetic acid-induced writhings and ameliorated the formalin-induced inflammatory phase dose-dependently. Whereas, 40 mg/kg dose of β-sitosterol abrogated the formalin-induced neurogenic phase. Substance-P abrogated the effect of β-sitosterol in both neurogenic and inflammatory phases. Whereas, L-arginine only abrogated the inflammatory phase. In biochemical analysis, β-sitosterol treatment reduced the level of interleukin-6 (IL-6), thiobarbituric acid reactive substances (TBARS) and increased the level of reduced glutathione (GSH). Furthermore, L-arginine and substance-P abrogated the GSH increasing and TBARS lowering effect of β-sitosterol (40 mg/kg). Overall, the current study delineated that β-sitosterol may induce an anti-nociceptive effect via inhibiting the IL-6, oxidative stress, cyclo-oxygenase and nitric oxide.

Modulation of inflammatory mediators involved in the antinociceptive and anti-inflammatory effects of a new thioamide derivative: thiocyanoacetamide

Inflammatory pain is part of the body's defense mechanism and plays an important role in the healing process. Although some drugs are efficient and intensively used for their potent anti-inflammatory properties, they present problematic side effects. The aim of this study was to evaluate the anti-nociceptive effect of the thiocyanoacetamide (Thm) compared to paracetamol (Para), dexamethasone (Dex) and morphine (Morph) and to study inflammatory mediators on models of acute inflammatory pain in rats using the formalin injection test in the hind paw of rats as chemical stimulus. The obtained results showed significant modulation of pain by Thm pretreatment with a maximum at an effective dose (10 mg/kg) proved by the absence of licking and biting of the affected paw during the early and late phases of inflammation. This effect was comparable to Dex at 10 mg/kg, Para at 400 mg/kg and less than Morph at 5 mg/kg pretreatment doses. The study of anti-inflammatory targets showed that Thm pretreatment maintained plasma serotonin release at normal level compared to the negative control group (T-) and corrected the decrease in the plasma level of prostaglandins after inflammatory induction with no variation in the level of histamine in different groups. The evaluation of inflammation mediators demonstrated that the pretreatment with Thm induced the decrease in the amount of both IL-1 Beta and TNF alpha in plasma and the increase in their amount in the tissue of the injection site. The Thm has been promoted as an anti-nociceptive drug that induces modulation of inflammatory mediators.

Highly potent anti-inflammatory, analgesic and antioxidant activities of 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine thiones

Four series of tetrahydro-2H-1,3,5-thiadiazine-2-thiones (series A and B including two novel enantiopure isomers), tetrahydro-2H-1,3,5-thiadiazine-6-thiones (series C) and N-3 ester derivatives of tetrahydro-2H-1,3,5-thiadiazine-6-thiones (series D) were synthesized and evaluated for their anti-inflammatory, analgesic and anti-oxidant activities. These THTT analogues specially series D were first time examined for their in vitro anti-inflammatory, in vivo analgesic and anti-oxidant activities. Among them lipophilic compounds (series B and D) were found to be highly active for anti-inflammatory evaluation with IC₅₀ values between 5.1-16.9 and 4.1-32.4 μM, respectively when compared with the standard drug ibuprofen IC₅₀ = 11.2 μM. The structure-activity relationship exposed the importance of lipophilic substituents especially ester and n-propyl group for inhibition of inflammation. The molecular docking studies demonstrated that all the active analogues of THTT have notable binding relations with Arg120 of the active sites of COX-1 enzyme either through CS moiety of the THTT nucleus or with COO attached at N-3 of THTT nucleus. In vivo analgesic activity of the selected THTT compounds 14, 17, 18, 19 (series B) and 28 (series D) were also carried out by acetic acid-induced writhing procedure. The compound 28 showed significant anti-nociceptive/analgesic activity at the oral dose of 5 mg/kg body weight with the percent protection (32.05 %) when compared with standard indomethacin at 10 mg/kg (48.83 %). Additionally, these compounds demonstrated the moderate level of antioxidant potential with IC₅₀ values in the range of 60.9 to 93.6 μM (standard butylated hyroxyanisole; IC₅₀ = 44.2 μM). These results indicated that this class of heterocyclic compounds may be a template specially to design better anti-inflammatory and analgesic agents.

Effects of Ziziphus Jujuba Extract Alone and Combined with Boswellia Serrata Extract on Monosodium Iodoacetate Model of Osteoarthritis in Mice

Background

As a chronic joint condition, osteoarthritis (OA) is a common problem among older people. Pain, aching, stiffness, swelling, decreased flexibility, reduced function, and disability are the symptoms of arthritis.

Objectives

In this study, we tested the extracts of Ziziphus jujuba (ZJE) and Boswellia serrata (BSE) to reduce OA symptoms as an alternative treatment.

Methods

NMRI mice were administered an intra-articular injection of monosodium iodoacetate (MIA; 1 mg/10 mL) in the left knee joint cavity for the induction of OA. Hydroalcoholic extracts of ZJE (250 and 500 mg/kg), BSE (100 and 200 mg/kg), and combined ZJE and BSE were orally administered daily for 21 days. Following behavioral tests, plasma samples were collected to detect inflammatory factors. To screen for general toxicity, acute oral toxicity was evaluated.

Results

Oral administration of all the hydroalcoholic extracts significantly increased the locomotor activity, pixel values of the foot-print area, paw withdrawal threshold, the latency of the withdrawal response to heat stimulation, and decreased the difference between pixel values of hind limbs compared to the vehicle group. Also, the elevated levels of IL-1β, IL-6, and TNF-α were reduced. As tested in this study, ZJE and BSE were practically nontoxic and had a high degree of safety.

Conclusions

This study demonstrated that the oral administration of ZJE and BSE slows the progression of OA through anti-nociceptive and anti-inflammatory properties. Oral co-administration of ZJE and BSE extracts can be used as herbal medicine to inhibit OA progression.

Anxiolytic, anti-nociceptive and body weight reducing effects of L-lysine in rats: Relationship with brain serotonin an In-Vivo and In-Silico study

L-lysine (L-lys) had long been comprehended as an essential amino acid for humans. There were reports that the absence or inadequate availability of L-lys in the diet may lead to mental and physical impairments. The present study was designed to explore the effects of L-lys on body weight changes, cumulative food intake, anxiety-like behavior and pain perception in rats. 5-Hydroxytryptamine (5-HT, serotonin) metabolism, and tryptophan (Trp) levels in the midbrain (MB), hippocampus (HP), and prefrontal cortex (PFC) were also determined. Animals were treated with L-lys in doses of 0.5 g/kg and 1 g/kg for 20 days and behavioral studies were performed on day 1st and day 20th. After monitoring behaviors on day 20th, animals were killed to collect the serum and brain regions MB, HP and PFC. 5-HT metabolism and Trp levels were determined by HPLC-EC. The treatment produce no effect on food intakes but body weights were reduced. 20 days administration of L-lys produced an anxiolytic effect and increased exploratory activity on day 1st. Repeated administration of L-lys increased 5-HT levels in the PFC and HP. 5-Hydroxyindoleacetic acid (5-HIAA), the metabolite of 5-HT, decreased in the HP. Trp, the precourser of 5-HT, decreased in the PFC. Results suggested a decrease in 5-HT degredation in enhancing 5-HT levels. Results of in-silico analysis showed that lysine had a potential binding affinity for MAO (monoamine oxidase) A and B with an energy of (-4.8 kcal/mol and -5.3 kcal/mol) respectively. The molecular dynamic simulation study revealed the stability of L-lys after 10 ns for each protein. Conclusively, the present study showed that L-lys produced an anxiolytic effect and reduced body weight. These beneficial effects were associated with an increase in 5-HT levels in the PFC and HP. In-silico analysis suggested that 5-HT increase were due to the binding of L-lys with MAOs resulting in an inhibition of the degradation of monoamine.

Herbal root extracts in Ben-Cha-Moon-Yai remedy attenuated pain-like behaviors and inflammation through the opioid and prostaglandin systems

ETHNOPHARMACOLOGICAL RELEVANCE

Ben-Cha-Moon-Yai (BMY) remedy used in Thai traditional medicine as an anti-inflammatory, analgesic, and antipyretic agent compromises five herbal root extracts of equal weights: Aegle marmelos (L.) Corrêa (AM), Oroxylum indicum (L.) Kurz (OI), Dimocarpus longan Lour. (DL), Dolichandrone serrulata (Wall. ex DC.) Seem. (DS), and Walsura trichostemon Miq. (WT).

AIM OF THE STUDY

To assess the anti-nociceptive and anti-inflammatory effects of the root extracts of all five species of BMY in experimental animal (mouse) models to ensure the rational use of herbal products in Thai traditional medicine.

MATERIALS AND METHODS

Root extracts prepared by ethanol and water extraction were used for the biological assays in animal models at five dose levels: 25, 50,100,200 & 400 mg/kg. The anti-nociceptive activity was evaluated based on hot-plate latency, duration of paw licking induced by formalin, and abdominal writhing induced by acetic acid. Carrageenan- and prostaglandin-induced paw oedema models were used to determine the anti-inflammatory activity.

RESULTS

The oral administration of AM, DS and WT root extracts displayed significant analgesic effects in the hot-plate test, both phases (early and late) of formalin test and acetic-acid induced writhing test at different dose levels. OI and DL only produced significant analgesia in the late phase of the formalin test and writhing test. The pretreatment of animals with the non-selective opioid receptor antagonist naloxone, reverse AM, DS and WT induced-antinociceptive activity. In both carrageenan and prostaglandin-induced paw oedema tests, all five herbal plant root extracts significantly reduced paw oedema at 3 h or more at different dose levels. Rotarod test results showed no effects of five herbal plant root extracts on the balance and the motor coordination at the highest dose level evaluated (400 mg/kg).

CONCLUSION

The root extracts of AM, DS, and WT possess both central and peripheral anti-nociceptive properties, while OI and DL possess only peripheral analgesic properties. All five root extracts own anti-inflammatory properties, which might be due to their activity on the prostaglandin system. Altogether these findings ensure the rational use of BMY remedy in Thai traditional medicine.

An in vivo evaluation of anti-inflammatory, analgesic and anti-pyretic activities of newly synthesized 1, 2, 4 Triazole derivatives

Background

In recent years, 1, 2, 4-triazole and its derivatives have been reported to be pharmacologically significant scaffolds. They possess analgesic, anti-tubercular, anti-inflammatory, anti-convulsant, anti-oxidant, anti-fungal, anti-cancer, anxiolytic and anti-depressant activity. This study was designed and conducted to evaluate the potential anti-inflammatory, analgesic and antipyretic activities of Triazole derivatives.

Methods

Swiss albino (male and female) mice weighing 20-30 g (10-24 weeks female), (5-14 weeks male) and Wister Kyoto rats (male and female) weighing 200-300 g (8-10 weeks old) were used for the present study. Anti-inflammatory activity was checked using Lambda carrageenan (λ) and egg albumin-induced paw edema models. Analgesic via Writhing Reflex induced by acetic acid and formalin, furthermore anti-pyretic activity was assessed by yeast induced pyrexia.

Results

Both of the test compounds exhibited encouraging anti-inflammatory analgesic and antipyretic results when compared with standard drug ibuprofen. The maximum inhibition of edema for the compound (S)-1-(4-Amino-5-mercapto-4H-1,2,4-triazole-3-yl) ethanol [3] was found to be (91)% as compared to reference drug ibuprofen (82)%, while (S)-1-(6-Phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)ethanol [5e] showed equipotent results to ibuprofen (81)%. The derivatives were also screened for their anti-nociceptive activity by Acetic acid writhing and tail immersion test. Compound 3 showed a significant reduction in wriths (83)% as compared to standard drug ibuprofen 71.5% and [5] showed comparable results to ibuprofen by exhibiting 70% reduction in writh at the same dose as that of standard drug, moreover, there were no signs of toxicity being observed after administration of high doses of test compounds to mice.

Conclusions

It is evident from the results that compounds 3(compound A) and 5(compound B) are a potential candidate for anti-inflammatory, analgesic and anti-pyretic and the scaffold could be used for further structural modifications. Further studies would help to evaluate their molecular mechanism of action regarding these beneficial activities.

LASSBio-596: a New Pre-clinical Candidate for Rheumatoid Arthritis?

Pain and inflammatory disorders are significant health problems because of prevalence and associated disabilities. In this context, LASSBio-596 is a hybrid compound able to modulate TNF-α and phosphodiesterases 4 and 5, exhibiting an anti-inflammatory effect in the pulmonary inflammatory model. Aiming at a better description of the activities of LASSBio-596, we initially conducted nociception tests (acetic acid-induced abdominal writhing, glutamate, and formalin-induced nociception and hot plate test) and later inflammatory tests (acute, peritonitis; and chronic, arthritis) that directed us to this last one. In the abdominal writhing test, there was a dose-dependent inhibition, whose response occurred at the maximum dose (50 mg/kg, p.o.), used in the subsequent tests. LASSBio-596 also inhibited nociception induced by chemical (glutamate by 31.9%; and formalin, in both phases, 1st phase: 25.7%; 2nd phase: 23.9%) and thermal agents (hotplate, by increased latency for pain at two different times). These effects were independent of the motor function, legitimated in rotarod. As there was a response in the inflammatory component of nociception, we performed the peritonitis test, in which migration was inhibited by LASSBio-596 by 39.9%. As the inflammatory process is present in autoimmune diseases, we also performed the arthritis test. LASSBio-596 reduced paw edema from the 15th day to the 21st day of treatment (no liver changes and with fewer paw injuries). In addition, LASSBio-596 decreased serum levels of TNF-α by 67.1%. These data demonstrated the antinociceptive effect of LASSBio-596 and reinforces its anti-inflammatory property (i.e., RA), amplifying the therapeutic potential of this molecule.

Central and peripheral pain intervention by Ophiorrhizarugosa leaves: Potential underlying mechanisms and insight into the role of pain modulators

ETHNOPHARMACOLOGICAL RELEVANCE

Ophiorrhiza rugosa var. prostrata is a traditional medicinal plant used by the indigenous and local tribes (Chakma, Marma and Tanchangya) of Bangladesh for the management of chest pain, body ache, and earache. However, the knowledge of anti-nociceptive and anti-inflammatory potentials of this plant is scarce.

AIM OF THE STUDY

Therefore, we scrutinized the anti-nociceptive and anti-inflammatory properties of O. rugosa leaves along with its possible mechanism(s) of action using chemical and heat-induced pain models.

METHODS AND MATERIALS

O. rugosa was extracted using 100% ethanol (EEOR) followed by exploring phytochemicals and assessing acute toxicity. To determine anti-nociceptive potentials, chemical-induced (acetic acid and formalin) and heat-induced (hot plate and tail immersion) nociceptive models were followed. To investigate the possible involvement of opioid receptors during formalin, hot plate, and tail immersion tests, naltrexone was administered whereas methylene blue and glibenclamide were used to explore cGMP involvement and ATP-sensitive K⁺ channel pathways, respectively. Moreover, the anti-inflammatory potential was assessed using the carrageenan-induced paw edema test model. Motor behaviours of EEOR were assessed by the open-field test. Finally, bioactive constituents (identified by GC-MS) from O. rugosa were subjected to molecular docking and ADME/t analysis to evaluate its potency and safety.

RESULTS

During chemical-induced and heat-induced pain models, EEOR exhibited significant and effective nociception suppression at all experimental doses (200 and 400 mg/kg). Also, the administration of naltrexone corroborated the association of opioid receptors with the anti-nociceptive activity by EEOR. Similarly, cGMP and ATP-sensitive K⁺ channel pathways were also found to be involved in the anti-nociceptive mechanism. Furthermore, significant and dose-dependent inhibition of inflammation induced by carrageenan was recorded for EEOR. Both doses of EEOR did not affect the animal's locomotor capacity in the open-field test. Besides, in silico test identified the key compounds (loliolide, harman, squalene, vitamin E, and gamma-sitosterol) that inhibited some particular receptors regarding pain and inflammation.

CONCLUSION

This research exposes central and peripheral pain intervention as well as anti-inflammatory activity of O. rugosa. Also, the identified compounds from this plant support its activities by effectively inhibiting anti-nociceptive and anti-inflammatory receptors. Overall, these outcomes valorize the ethnomedicinal efficacy of O. rugosa in managing various painful conditions.

Mechanistic evaluation of a novel cyclohexenone derivative's functionality against nociception and inflammation: An in-vitro, in-vivo and in-silico approach

The synthesis of a novel cyclohexanone derivative (CHD; Ethyl 6-(4-metohxyphenyl)-2-oxo-4-phenylcyclohexe-3-enecarboxylate) was described and the subsequent aim was to perform an in vitro, in vivo and in silico pharmacological evaluation as a putative anti-nociceptive and anti-inflammatory agent in mice. Initial in vitro studies revealed that CHD inhibited both cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) enzymes and it also reduced mRNA expression of COX-2 and the pro-inflammatory cytokines TNF-α and IL-1β. It was then shown that CHD dose dependently inhibited chemically induced tonic nociception in the abdominal constriction assay and also phasic thermal nociception (i.e. anti-nociception) in the hot plate and tail immersion tests in comparison with aspirin and tramadol respectively. The thermal test outcomes indicated a possible moderate centrally mediated anti-nociception which, in the case of the hot plate test, was pentylenetetrazole (PTZ) and naloxone reversible, implicating GABAergic and opioidergic mechanisms. CHD was also effective against both the neurogenic and inflammatory mediator phases induced in the formalin test and it also disclosed anti-inflammatory activity against the phlogistic agents, carrageenan, serotonin, histamine and xylene compared with standard drugs in edema volume tests. In silico studies indicated that CHD possessed preferential affinity for GABAA, opioid and COX-2 target sites and this was supported by molecular dynamic simulations where computation of free energy of binding also favored the formation of stable complexes with these sites. These findings suggest that CHD has prospective anti-nociceptive and anti-inflammatory properties, probably mediated through GABAergic and opioidergic interactions supplemented by COX-2 and 5-LOX enzyme inhibition in addition to reducing pro-inflammatory cytokine expression. CHD may therefore possess potentially beneficial therapeutic effectiveness in the management of inflammation and pain.

Albizia lebbeck and Albizia zygia volatile oils exhibit anti-nociceptive and anti-inflammatory properties in pain models

ETHNOPHARMACOLOGICAL RELEVANCE

Albizia lebbeck and Albizia zygia are used in Nigeria, South Africa and other countries for the treatment of flu, fever, pain, epilepsy, and inflammation.

AIM OF THE STUDY

Application of plant essence for treating ailments is common among local communities. This research was designed to characterize the volatile compounds and evaluate the toxicity, anti-inflammatory and anti-nociceptive properties of this plant species.

MATERIALS AND METHODS

The volatile oils were analysed comprehensively utilizing gas chromatography-flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS) using the HP-5 column. The toxicity was evaluated using the toxicity assay. The anti-nociceptive and anti-inflammatory assays were analysed by a hot plate, Formalin, and carrageenan-induced edema assays, respectively.

RESULTS

The essential oils were obtained in a yield of 0.1% (v/w) calculated on a dry weight basis for both oils. The main compounds of A. lebbeck were 2-pentylfuran (16.4%), (E)-geranyl acetone (15.46%), (E)-α-ionone (15.45%) and 3-Octanone (11.61%), while the oil of A. zygia is mainly hexahydrofarnesyl acetone (33.14%), (E)-methyl isoeugenol (11.7%) and 2-methyl tetradecane (6.64%). The volatile oils are non-toxic to about 5000 mg/kg dose. Albizia zygia significantly (P < 0.001) suppressed the nociceptive afferent fibres in a non-dose dependent manner in comparison to A. lebbeck in the hot plate model. Both oils inhibited nociceptive mediators at both phases of the formalin-induced assay, with a maximum inhibition (100%) at the inflammatory stage. The volatile oils inhibited the Carrageenan-induced inflammation at all phases ranging from P < 0.05 to P < 0.001. The probable pro-inflammatory inhibitory mechanism might be the suppression of some pain biomarkers such as histamine, serotonin, bradykinin, and the Interleukins (ILs) induced by the edema. Volatile constituents such as ionones, eugenol derivatives and other compounds cause the anti-nociceptive and anti-inflammatory activities reported.

CONCLUSION

This is the first report of the volatile oils and bioassays of Albizia zygia, while the study also confirms previous studies of A. lebbeck. Generally, the findings further prove the use of the plants as pain ameliorating agents.

β-blocker prescription is associated with lower cumulative risk of knee osteoarthritis and knee pain consultations in primary care: a propensity score matched cohort study

Objectives

To examine the association between β-blocker prescription and first primary-care consultation for knee OA, hip OA, knee pain and hip pain.

Methods

Data source: Clinical Practice Research Datalink. Participants aged ≥40 years in receipt of new oral β-blocker prescriptions were propensity score (PS) matched to an unexposed control. Cox proportional hazard ratios (HRs) and 95% CIs were calculated, and adjusted for non-osteoporotic fractures, number of primary-care consultations for knee or hip injury, and, the number of primary-care consultations, out-patient referrals and hospitalizations in the 12 months preceding cohort entry. Analysis was stratified according to β-blocker class and for commonly prescribed drugs. P < 0.05 was considered statistically significant.

Results

A total of 111 718 β-blocker–exposed participants were 1:1 PS matched to unexposed controls. β-blocker prescription was associated with reduced cumulative risk of knee OA, knee pain, and hip pain consultations [with a HR (95% CI) of 0.90 (0.83, 0.98), 0.88 (0.83, 0.92) and 0.85 (0.79, 0.90), respectively]. Propranolol and atenolol were associated with a lower incidence of knee OA and knee pain consultations with a HR of between 0.78 and 0.91. β-blockers were associated with reduced incidence of consultation for large-joint lower-limb OA/pain as a composite outcome, defined as the earliest of knee OA, knee pain, hip OA or a hip pain consultation [with a HR (95% CI) of 0.87 (0.84, 0.90)].

Conclusion

Commonly used β-blockers have analgesic properties for musculoskeletal pain. Atenolol might be a therapeutic option for OA and cardiovascular co-morbidities in which β-blockers are indicated, while propranolol may be suitable for people with co-morbid anxiety. A confirmatory randomized controlled trial is needed before clinical practice is changed.

Anti-nociceptive and anti-inflammatory activities of ethanol extract and fractions of Morus mesozygia Stapf (Moraceae) leaves and its underlying mechanisms in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Morus mesozygia Stapf (Moraceae), commonly known as African mulberry, is traditionally used for the treatment of inflammatory disorders such as rheumatism and dermatitis.

AIM

This work aimed to evaluate the anti-nociceptive and anti-inflammatory effects of its ethanol (EEMm) extract, and ethylacetate fraction (EAFMm).

METHODS

The anti-nociceptive and anti-inflammatory effect of ethanol extracts of M. mesozygia (EEMm), and its ethylacetate (EAFMm) and residual aqueous fraction (RAFMm) was evaluated in hotplate, acetic acid and formalin tests and as well in membrane stabilizing assay and carrageenan-induced paw oedema models. Mechanism of anti-inflammation of EAFMm was investigated in the carrageenan-induced air-pouch model.

RESULTS

In the hot plate test of nociception, only the EAFMm showed significant (p < 0.05) anti-nociceptive activity. The extract and fractions significantly reduced number of writhing with EAFMm (400 mg/kg) showing highest inhibition (66.5%) in the acetic acid-induced writhing in mice. EEMm and EAFMm (400 mg/kg) significantly reduced the paw licking time in the early and late phases of the formalin test. The extract and fractions showed good membrane stabilizing activity comparable to indomethacin. EAFMm (100 and 400 mg/kg) showed the highest inhibition of paw oedema (53.4% and 58.1%) in the carrageenan-induced paw oedema model. The EAFMm (100 and 400 mg/kg) reduced exudate volume relative to carrageenan-control (2.64 ± 0.22, 2.08 ± 0.15 vs 3.83 ± 0.18 mL) and neutrophils (8.98 ± 1.36, 8.00 ± 0.22 vs 20.51 ± 1.14) in carrageenan-induced pouch. EAFMm significantly reduced exudate volume, pro-inflammatory cytokines and the expression of COX-2 and NFκB.

CONCLUSION

M. mesozygia leaves demonstrated anti-nociceptive and anti-inflammatory activities by suppressing oxidative stress, pro-inflammatory cytokines, cyclooxygenase-2, and nuclear factor kappa B.

Anti-nociceptive and antioxidant activity of betaine on formalin- and writhing tests induced pain in mice

Pain is a physiological response which is mediated via the central and peripheral nervous system. Betaine, is a methyl glycine derivative and a commonly used nutrient supplement. The main purpose of the current paper is to determine the possible anti-nociceptive and antioxidant activity and sedative effect of betaine in mice. Adult male albino mice were divided into two categories, formalin and writhing tests. In the formalin test, mice were injected with betaine (10, 20 and 30 mg/kg) or morphine (5 mg/kg). For co-injections mice received betaine (30 mg/kg) + naloxone (2 mg/kg) or atropine (1 mg/kg), chlorpheniramine (20 mg/kg), flumazenil (5 mg/kg), cimetidine (12.5 mg/kg) and cyproheptadine (4 mg/kg). Then the formalin test was done and paw licking time was determined. In the writhing test, injections were the same but the animals were injected with acetic acid (0.6 %) and the percentage of writhing inhibition was recorded. At the end of the study, blood antioxidant levels were determined. According to the results, betaine reduced the pain response in a dose-dependent manner. Co-administration of the naloxone + betaine or flumazenil + betaine significantly decreased the anti-nociceptive effect of betaine on the licking and biting time of the injected paw and inhibited the number of writhing movements. Betaine decreased malondialdehyde (MDA) and improved superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels in formalin receiving mice. No adverse locomotion and sedation effect were observed in betaine-treated mice. These findings suggest that betaine has anti-nociceptive and antioxidant activity in mice, and its anti-nociceptive role interacts with opioidergic and GABA receptors.

Antipyretic and anti-nociceptive effects of methanol extract of leaves of Fimbristylis miliacea in mice model

ETHNOPHARMACOLOGICAL RELEVANCE

Fimbristylis miliacea (L.) Vahl (Cyperaceae) is a grass like herb usually grows as a weed in rice fields and is mainly distributed in tropical or sub-tropical countries of south and south-east Asia, central America, northern Australia and west Africa. The plant has been traditionally used to treat fever as a form of poultice.

AIM OF THE STUDY

The present study aimed to investigate antipyretic and anti-nociceptive effects of methanol extract of leaves of Fimbristylis miliacea in mice model.

MATERIALS AND METHODS

Antipyretic effect of Fimbristylis miliacea was examined using Baker's yeast induced hyperthermia test. Anti-nociceptive effect was investigated using acetic acid induced writhing test, formalin induced hind paw licking test and hot plate test.

RESULTS

The extract at concentration of 400 mg/kg produced significant reduction in body temperature after 0.5 h of administration (4.12 °F, p ≤ 0.001) and continued to decrease (after 4 h, 5.92 °F, p ≤ 0.001). Extracts at 100 mg/kg and 200 mg/kg decreased the temperature by about 2.77 °F (from 99.47 °F to 96.7 °F) and 5.58 °F (98.2 °F-92.62 °F) respectively after 4 h whereas paracetamol dropped by about 7.2 °F (p ≤ 0.001). The extract showed significant decrease in number of writhes at all concentrations. Highest effect was found at 200 mg/kg having 35.7 writhes (p ≤ 0.001), much lower than control (89.2); standard drug diclofenac showed 23.2 writhes. Percent inhibition of writhing were 54.26 and 73.99 for 200 mg/kg and diclofenac respectively. The result of hind paw licking test also corroborated writhing test. Significant reduction in percent inhibition of licking was observed mainly in late phase. Percent inhibition of licking were 93.77 and 51.55 for 400 mg/kg extract and diclofenac respectively. In hot plate test, extract at 400 mg/kg showed significant increase in latency from 10.77 s to 13.59 s (p ≤ 0.05). Extract at this dose after 2 h demonstrated greater percent maximal effect (43.26%) compared to ketorolac (40.19%).

CONCLUSION

The experiment confirmed the traditional use of F. miliacea in the treatment of fever with possible anti-nociceptive effects.

Evaluation of anti-nociceptive and anti-inflammatory activities of the methanol extract of Holigarna caustica (Dennst.) Oken leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Holigarna caustica (Dennst.) is commonly used in traditional medicine to treat a variety of painful conditions such as eye irritation, inflammation, arthritis, skin diseases, cuts and wounds.

AIM OF THE STUDY

The present study was undertaken to investigate the anti-nociceptive and anti-inflammatory activities of the methanol extract of H. caustica leaves and to elucidate its possible mechanism(s) of action.

MATERIALS AND METHODS

Fresh leaves of H. caustica were collected, dried, and extracted with methanol (MEHC). MEHC was subjected to activity testing, using chemical-induced (acetic acid and formalin test) and heat-induced (hot plate and tail immersion test) pain models. To determine the possible mechanism behind the anti-nociceptive activity of MEHC, the opioid antagonist naltrexone was used to evaluate the involvement of opioid receptors in the case of formalin, hot plate and tail immersion tests, while the involvement of the cGMP and ATP-sensitive K⁺ channel pathways were assessed using methylene blue and glibenclamide respectively, in the acetic acid-induced writhing test. In parallel, the carrageenan-induced paw oedema model was used to determine the anti-inflammatory potential of the extract. Exploratory and motor behaviours were evaluated by the open-field test. Various bioactive compounds potentially responsible for the anti-nociceptive and anti-inflammatory activities were ascertained using GC-MS analysis.

RESULTS

MEHC showed strong, significant and dose-dependent anti-nociceptive activity in all chemical-induced and heat-induced pain models at all experimental doses. The association of opioid receptors with the observed anti-nociceptive effects was confirmed by using naltrexone. The cGMP and ATP-sensitive K⁺ channel pathway was also shown to be involved in the anti-nociceptive activity of MEHC. In addition, MEHC exhibited a dose-dependent inhibition of inflammatory oedema induced by carrageenan. MEHC was not connected with changes in either the locomotor activity or motor responses of mice. In a GC-MS analysis, 40 compounds were identified, among which twelve are documented bioactive compounds with potent analgesic and anti-inflammatory properties.

CONCLUSIONS

Our current study revealed that MEHC possesses strong central and peripheral anti-nociceptive as well as anti-inflammatory activity. It may also be concluded that both opioid receptors as well as the cGMP and ATP-sensitive K⁺ channel pathway are involved in the anti-nociceptive mechanism of MEHC. This study rationalizes the ethnomedicinal use of H. caustica leaves in various painful conditions.

Comprehensive behavioral study of the effects of vanillin inhalation in mice

Vanillin is widely used in food and cosmetics, among other substances, for its sweet smell. However, the neuropsychological effects of vanillin inhalation have not been elucidated. In this study, we investigated the effect of vanillin inhalation on mouse behavior. First, we investigated whether the aroma of vanillin was attractive or repulsive for mice. Thereafter, the mice inhaled vanillin for 20 min before each test in a series of behavioral tests (elevated plus maze, open field, Y-maze, tail suspension, cotton bud biting, and Porsolt forced swim tests). In these tests, the mice showed a neutral response to vanillin. Mice that inhaled vanillin had a suppressed pain response in the hot plate test. In addition, the grip strength of the forelimbs of mice that inhaled vanillin was decreased. No significant differences were found between the mice inhaling vanillin and control mice in the open field, Y-maze, tail suspension, forced swimming, and aggression tests. These results show that vanillin inhalation has anti-nociceptive effects, similar to other routes of administration. The results also show that vanillin inhalation does not cause significant behavioral effects.

Anti-pain and anti-inflammation like effects of Neptune krill oil and fish oil against carrageenan induced inflammation in mice models: Current statues and pilot study

Although inflammation is a reactive to injurious stimuli and considered as beneficial process in body, but it causes some discomforts, such as pain. Murine dietary contains appreciable amounts of fatty acids and antioxidants which encourages researchers to focus on their potential therapeutic effects. This study is aimed to examine the analgesic and anti-inflammatory activity of Neptune krill oil (NKO) and fish oil (FO) in rodent model which are two well-known sources of rich content of n-3 polyunsaturated fatty acids (n-3 PUFAs), mostly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). NKO and FO were used at the same dose of 500 mg and also balanced at similar doses of EPA: 12 in NKO vs. 12 in FO wt%, DHA: 7 NKO vs. 8 FO wt%. Application of NKO and FO in acetic acid-induced writhing effect, hot plate, and formalin induced test, indicated the nociceptive activity of the two tested drugs in comparison with normal saline. Also, the anti-inflammatory effect of these supplements was confirmed by carrageenan test. Analysis of cytokines levels in the blood samples of the mice after induction inflammation by carrageenan indicated decreased levels of those proteins compared to that in the normal groups. Both tested drugs, effectively could reduce severe inflammation and pain in rodents in comparison with the references drugs (depends on the tests); however, NKO was found to be more effective.

The anti-inflammatory and anti-nociceptive effects of Korean black ginseng

BACKGROUND

Different processing conditions alter the ginseng bioactive compounds, promoting or reducing its anti-inflammatory effects. We compared black ginseng (BG) - that have been steamed 5 times - with red ginseng (RG).

HYPOTHESIS/ PURPOSE

To compare the anti-inflammatory activities and the anti-nociceptive properties of RG and BG.

METHODS

Nitric Oxide (NO) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay, quantitative Reverse Transcriptase-Polymerase Chain Reaction (qRT-PCR), western blot, xylene-induced ear edema, carrageenan-induced paw edema RESULTS: The ginsenoside contents were confirmed using high-performance liquid chromatography (HPLC) and has been altered through increased processing. The highest concentration of these extracts inhibited NO production to near-basal levels in lipopolysaccharide (LPS)-stimulated RAW 264.7 without exhibiting cytotoxicity. Pro-inflammatory cytokine expression at the mRNA level was investigated using qRT-PCR. Comparatively, BG exhibited better inhibition of pro-inflammatory mediators, iNOS and COX-2 and pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α. Protein expression was determined using western blot analysis and BG exhibited stronger inhibition. Xylene-induced ear edema model in mice and carrageenan-induced paw edema in rats were carried out and tested with the effects of ginseng as well as dexamethasone and indomethacin - commonly used drugs. BG is a more potent anti-inflammatory agent, possesses anti-nociceptive properties, and has a strong potency comparable to the NSAIDs.

CONCLUSION

BG has more potent anti-inflammatory and anti-nociceptive effects due to the change in ginsenoside component with increased processing.

Anti-nociceptive and anti-inflammatory potentials of Akebia saponin D

Akebia saponin D, which is originates from Dipsacus asper Wall, has been used as a tonic, an analgesic and anti-inflammatory agent for the therapy of low back pain, rheumatic arthritis, traumatic hematoma, habitual abortion and bone fractures in traditional Chinese medicine. However, the anti-nociceptive and anti-inflammatory activity and mechanism of Akebia saponin D has been rarely reported. The aim of this study was to investigate the anti-nociceptive and anti-inflammatory activity of Akebia saponin D and to assess its possible mechanism. The anti-nociceptive effect was measured by formalin test, hot plate, and acetic acid-induced writhing in mice while the anti-inflammatory effect was measured by carrageenan induced paw edema test, xylene-induced ear swelling and acetic acid-induced vascular permeability in mice and rats. Furthermore, anti-inflammatory effect was also measured in vitro using LPS-induced RAW 264.7 cells. Our results demonstrated that Akebia saponin D dose-dependently decreased the licking time in the formalin test, delayed the reaction time of mice to the hot plate, and inhibited acetic acid-induced writhing. Treatment of Akebia saponin D attenuated the carrageenan induced paw edema in rats, inhibited the mouse ear swelling, and decreased Evans blue concentration in acetic acid induced vascular permeability test, revealing its strong anti-inflammatory effect. Akebia saponin D significantly decreased NO production and iNOS expression. Our results indicate that Akebia saponin D has anti-nociceptive and anti-inflammatory effects. It will provide experimental evidences for the use of Akebia saponin D and can be used to develop a therapeutic drug against pain and inflammation related diseases.

Clarke) Munir.: Chemical characterization, anti-nociceptive and anti-inflammatory activities of methanol extract of leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Sphenodesme involucrata var. paniculata (C. B. Clarke) Munir is native as well as endemic to South India. Its leaves are used in folklore medicine to treat pain and rheumatism.

OBJECTIVE

This study was aimed to investigate the chemical characterization, anti-nociceptive and mode of action underlying the anti-inflammatory effects of methanol extract of S. involucrata leaves (MESi).

METHODS

Phytoconstituents of MESi was analyzed using colorimetric and liquid chromatography-mass spectrometry (LC-MS) methods, and the oral acute toxicity was evaluated in mice up to 2000 mg/kg. The anti-nociceptive effect was evaluated in hot plate and writhing tests; whereas the anti-inflammatory effect was investigated using carrageenan, cotton pellet and lipopolysaccharide (LPS)-induced peritonitis models at doses of 100, 200 and 400 mg/kg. Additionally nitric oxide (NO) and inflammatory cytokines levels were also evaluated.

RESULTS

MESi exhibited the high content of phenolics and flavonoids as well as compounds like austricine, benzylglucosinolate, gossypin, justicidin B and cirsimarin were detected in LC-MS. In the acute toxicity study, oral administration of MESi did not cause any toxic effect and mortality up to 2000 mg/kg body weight in mice. In the anti-nociceptive tests, MESi augmented the latency period at higher dose (400 mg/kg), on the other hand attenuated writhings at the dose of 400 mg/kg by 87.87% (p < 0.001). In the carrageenan induced paw oedema MESi significantly inhibited the oedema formation at dose 400 mg/kg by 32.1%; besides, anti-inflammatory effect was registered in the cotton pellets-induced inflammation model at doses 200 and 400 mg/kg by 27.09% (p < 0.001) and 35.47% (p < 0.001) respectively. On the other hand, MESi appreciably reduced leukocyte, neutrophils infiltration, nitric oxide, TNF-α and IL-1β levels and increased the IL-10 level in the (LPS)-induced peritonitis model.

CONCLUSION

The results conclude that MESi has no acute toxic effect and it demonstrated potent anti-nociceptive and anti-inflammatory activities. Its anti-nociceptive activities are probably mediated through peripheral and central mechanisms. The anti-inflammatory effect of MESi involved the inhibition of neutrophils migration and the modulation of Th₁ and Th₂ cytokines, besides the attenuation of production of PGE₂ and NO. LC-MS analysis revealed the predominant presence of the austricine, benzylglucosinolate, gossypin, justicidin B and cirsimarin compounds, which are possibly involved in the anti-nociceptive and anti-inflammatory effects of MESi. The current study provided supportive evidence for the folklore use of S. involucrata in the treatment of pain and inflammatory conditions.

Anti-nociceptive effect of methanol extract of leaves of Senna singueana in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Senna singueana (Del.) Lock (Fabaceae) is a shrub or tree found in Ethiopia and other African countries. It has been traditionally used for different conditions including treatment of pain conditions in humans and animals. Although various reports are available in the literature claiming different activities of the plant, scientific studies supporting analgesic potential of S. singueana are lacking and the present study aimed to investigate the antinociceptive effect of methanol extract of leaves of S. singueana in mice.

MATERIALS AND METHODS

Anti-nociceptive activity of S. singueana (200 mg/kg and 400 mg/kg, p.o) was investigated using acetic acid-induced writhing, formalin-induced paw licking, and hot plate tests. Acute oral toxicity was determined using a slightly modified guideline (423) of the Organization for Economic Cooperation and Development.

RESULTS

S. singueana extract increased the percentage of inhibition of writhing response and licking response (neurogenic and inflammatory phase) in acetic acid-induced writhing and formalin-induced paw licking tests, respectively. It also significantly (p ≤ 0.05) increased the percentage of mean maximal effect (%MPE) compared to control group in the hot-plate test. In all models, the combination of S. singueana with either diclofenac or morphine produced statistically significant increase (p ≤ 0.05) in the percentage of inhibition of writhing, paw licking, and %MPE compared to single treatment groups. It was also found that the 400 mg/kg extract produced higher antinociceptive effects (p ≤ 0.05) compared to the 200 mg/kg.

CONCLUSION

S. singueana leaves may have analgesic effect that is mediated through both peripheral and central mechanisms and could be used as adjuvant treatment to the modern analgesics.

f.) Robinson in experimental animal model

Mikania cordata is widely used for the treatment of cuts, wounds, and dengue fever in Bangladesh. In the present study, essential oil (12.5, 25 and 50 mg/kg) and two extracts, viz., chloroform and ethyl acetate extracts (200, 400, 800 mg/kg b.w.) were tested for peripheral and central anti-nociceptive activity by acetic acid-induced writhing and hot plate method, respectively. Carrageenan-induced rat paw edema assay and yeast-induced hyperthermia assay were also carried out to evaluate anti-inflammatory and antipyretic properties of oil and extracts, respectively at aforesaid doses. The essential oil (50 mg/kg), chloroform extract (800 mg/kg) and ethyl acetate extract (800 mg/kg) showed potent peripheral anti-nociceptive activity having 47.33%, 29.33% and 16.65% of writhing inhibition, respectively, comparable with standard diclofenac (52.0%). Essential oil (50 mg/kg), chloroform extract (800 mg/kg) and ethyl acetate extract (800 mg/kg) presented promising central anti-nociceptive activity as well having 95.86%, 79.18% and 42.37% elongation of reaction time, respectively, at 90 min after administration of essential oil, ethyl acetate extract and 60 min after administration of chloroform extract. In anti-inflammatory activity screening, the essential oil (50 mg/kg) produced the highest 72.80% edema inhibition at 4 h after administration of carrageenan which was comparable with that of standard phenylbutazoe (87.87%). On the other hand, chloroform extract (800 mg/kg) and ethyl acetate extract (800 mg/kg) showed up to 34.31% and 15.27% of edema inhibition, respectively, at 4 h after administration of carrageenan. In antipyretic assay, the essential oil and chloroform extract displayed a strong antipyretic effect in yeast-induced rats, whereas the ethyl acetate extract had no antipyretic activity. The present study revealed anti-nociceptive, anti-inflammatory and antipyretic potential of M. cordata which could be the therapeutic option against fever, inflammations as well as painful conditions and confirmed the traditional use of M. cordata.

In vivo anti-arthritic and anti-nociceptive effects of ethanol extract of Moringa oleifera leaves on complete Freund's adjuvant (CFA)-induced arthritis in rats

Background

The medicinal uses of plants are in many cases based exclusively on traditional knowledge without enough scientific evidences. Different parts of Moringa oleifera were traditionally used for the treatment of wide variety of ailments including arthritis and joints pain. The present study had been designed to evaluate the anti-arthritic and anti-nociceptive activities of ethanol extract of Moringa leaves, this being the most abundant plant part suitable for commercial mass production of botanical medicinal products.

Methods

Complete Freund's adjuvant (CFA)-induced arthritis in rats was used as disease model. CFA-induced inflammatory paw edema, body weight, arthritic index, X-ray radiography, hematological parameters, and walk track and locomotion analysis were all evaluated for the assessment of disease progression. In addition to that, anti-nociceptive activity was examined at different dose levels in both normal and arthritic-induced rats using Eddy's hot plate and tail flick thermal analgesia.

Results

The analysis of various arthritic assessment parameters used in this study revealed that Moringa extract has a considerable effect in preventing development or ameliorate arthritis disease severity. Moreover, the ethanol extract of Moringa leaves revealed significant anti-nociceptive activity at in both normal and CFA-induced arthritis rats in a dose-dependent manner.

Conclusion

Ethanol extract of Moringa leaves appears to be a really promising as analgesic and arthritis medication, but a larger and more detailed preclinical and clinical studies especially in human is highly recommended.

Anti-nociceptive and anti-inflammatory effects of the methanolic extract of Opuntia humifusa stem

OBJECTIVE

Opuntia humifusa (O. humifusa) Raf. has been used for the prevention and treatment of rheumatoid arthritis, inflammation, and cancer. Our study was designed to unveil the anti-nociceptive and anti-inflammatory effects of the methanolic extract of O. humifusa Raf stem (OHS).

MATERIALS AND METHODS

The anti-nociceptive effect was measured by hot plate, acetic acid-induced writhing, and tail flick assays in mice and rats. Moreover, the anti-inflammatory effect was measured by vascular permeability and carrageenan and serotonin-induced paw edema tests in rats. Furthermore, anti-inflammatory effect was also measured using macrophage-like LPS-induced RAW 264.7 cells.

RESULTS

OHS extract inhibited acetic acid-induced writhing (p<0.0001), and delayed the reaction time of mice to the hot plate-induced thermal stimulation (p<0.0001) and tail flick tests (p<0.05). OHS extract attenuated the carrageenan and serotonin-induced paw edema in rats (p<0.001). Similarly, OHS extract significantly decreased Evans blue concentration in acetic acid induced vascular permeability test (p<0.0001), revealing its strong anti-inflammatory effect. Finally, among four different fractions of OHS extract, n-butanol fraction strongly decreased NO production (p<0.0001) and iNOS expression in LPS-induced RAW 264.7 cells.

CONCLUSION

Our results suggest that the methanolic extract of O. humifusa stem can be used to develop a therapeutic or supportive drug and/or functional food against pain and inflammation related diseases.

Novel 2,4-dichlorophenoxy acetic acid substituted thiazolidin-4-ones as anti-inflammatory agents: Design, synthesis and biological screening

A library of fourteen 2-imino-4-thiazolidinone derivatives (1a-1n) has been synthesized and evaluated for in vivo anti-inflammatory activity and effect on ex-vivo COX-2 and TNF-α expression. Compounds 1k (5-(2,4-dichloro-phenooxy)-acetic acid (3-benzyl-4-oxo-thiazolidin-2-ylidene)-hydrazide) and 1m (5-(2,4-dichloro-phenooxy)-acetic acid (3-cyclohexyl-4-oxo-thiazolidin-2-ylidene)-hydrazide) exhibited in vivo inhibition of 81.14% and 78.80% respectively after 5h in comparison to indomethacin which showed 76.36% inhibition of inflammation without causing any damage to the stomach. Compound 1k showed a reduction of 68.32% in the level of COX-2 as compared to the indomethacin which exhibited 66.23% inhibition of COX-2. The selectivity index of compound 1k was found to be 29.00 in comparison to indomethacin showing selectivity index of 0.476. Compounds 1k and 1m were also found to significantly suppress TNF-α concentration to 70.10% and 68.43% in comparison to indomethacin which exhibited 66.45% suppression.

Analgesic and Antioxidant Activities of Stem Bark Extract and Fractions of Petersianthus macrocarpus

Background:

Petersianthus macrocarpus (Lecythidaceae) is widely used in the folk medicine in Nigeria to relieve pain and fever associated with malaria. This study evaluated the analgesic and antioxidant activities of the methanol extract and fractions of the stem bark of the plant.

Materials and Methods:

The analgesic activity was determined in mice using hotplate and acetic acid-induced writhing models. Morphine sulphate (5 mg/kg, i.p.) and aspirin (100 mg/ml, p.o.) were used as reference analgesic agents. The antioxidant potential was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical; reducing power, iron chelating properties and determination of total phenolic content.

Results:

The extract at 200 and 500 mg/kg, produced an insignificant (P > 0.05) increase in pain threshold in hotplate but a significant (P < 0.05) increase at 1000 mg/kg. The extract significantly (P < 0.05) reduced the writhing induced by acetic acid in mice in a dose dependent manner. Fractionation increased the analgesic activities significantly (P < 0.05) in ethyl acetate and aqueous fractions (200 mg/kg). The extract demonstrated strong DPPH radical scavenging activity with IC₅₀ 0.05 mg/ml, good reducing power and weak iron chelating activities. The total phenol content was 142.32 mg/gin term of gallic acid. The antioxidant effects were more pronounced in ethyl acetate and aqueous fractions.

Conclusion:

The findings of the study suggested that the extract has strong analgesic and antioxidant activities which reside mainly in the polar fractions thus confirming the traditional use of the plant to alleviate pains.

SUMMARY

Analgesic and antioxidant activities of extract and solvent fractions of Petersianthus macrocarpus investigated indicated that extract has analgesic and antioxidant properties that reside mainly in the polar fractions.

Abbreviations Used: DMSO: Dimethyl sulphoxide, ANOVA: analysis of variance, EDTA: ethylene diamne tetraacetic acid, SDM: standard deviation of mean, PGE: prostaglandins E, PDF: prostaglandins F.

Neuropharmacological properties of farnesol in Murine model

Research on new compounds of therapeutic value for behavioral disorders has progressed recently. Several studies have reported neuropharmacological activities of plant derived terpenes. Farnesol is a sesquiterpene whose most popular source is fruits but the anxiolytic activity for farnesol is still unknown. The present study was conducted on 32 male Swiss Albino mice (8 in each group) to evaluate the neuropharmacological properties of farnesol and its effects on plasma cortisol levels. Farnesol was administered intraperitoneally at single doses of 50 and 100 mg/kg, while diazepam 2 mg/kg was used as standard anxiolytic. Thirty minutes after injections, open field test (OFT), elevated plus maze (EPM), a forced swimming test (FST), and a hot plate test (HPT) were performed for evaluation of anxiety-like behavior, depression and nociception. In OFT, farnesol at the dose of 100 mg/kg led to significant decrease in locomotor activity (P<0.01). In EPM, only farnesol 100 mg/kg led to significant increase in the number of entries to the open arms and the time spent in open arms (P<0.01). Increase in immobility time in FST was seen in farnesol 50 and 100 mg/kg (P<0.001). Farnesol 100 mg/kg exerts significant prolongation in the latency of responses to noxious heat stimuli in HPT. Like diazepam, farnesol decreased plasma levels of cortisol. Results revealed that farnesol had anxiolytic, anti-nociceptive and depressant effects in murine models. The present study provides pharmacological evidence supporting the use of farnesol as a sedative for anxiety disorders.

Clinical evaluation of analgesic activity of guduchi (tinospora cordifolia) using animal model

INTRODUCTION

Pain is a very well-known signal of ill health and analgesics are the drugs that are used to relieve pain. The main problem with these drugs remains that of side effects. Safer alternatives are natural herbs. Guduchi (Tinospora cordifolia) is one such plant with analgesic potential but few studies are there.

OBJECTIVE

To evaluate the analgesic activity of commercially available extract of Guduchi (T. cordifolia).

MATERIALS AND METHODS

For this purpose commercially available extract of Guduchi (T. cordifolia) by Himalaya Drug Company, Bangalore was used. Albino rats were divided randomly in three groups of six rats each. Group 1 (control) received distilled water orally, group 2 (test) received T. cordifolia extract in dose of 300 mg/kg orally and group 3(standard) received Pentazocine in dose 10mg/kg intraperitoneally. Analgesic activity was evaluated using hot plate and abdominal writhing method. All the observations were analysed statistically using student's t-test.

OBSERVATION AND RESULTS

T. cordifolia extract significantly (p<0.05) increased the response time and decreased the number of writhes in hot plate method and abdominal writhing method respectively, on comparison with the control group.

CONCLUSIONS

The above findings suggest that this commercially available extract of Guduchi (T. cordifolia) possess analgesic activity. This analgesic activity probably involves peripheral as well as central mechanisms as the extract showed analgesic activity in both hot plate and abdominal writhing method.

Anti-nociceptive, anti-inflammatory and sedative activities of the extracts and chemical constituents of Diospyros lotus L

Diospyros lotus L. is traditionally used in various diseases including pain and sleep disorders. The pain and inflammation are the common problems, which are treated with various synthetic analgesic drugs, and associated the side effects. The natural products have gained significant importance over synthetic drugs. The importance of phyto-medicine the current study has been designed with the aim to investigate the analgesic and anti-inflammatory effects of Diospyros lotus and bioassay guided isolation from its crude fractions. Seven known compounds; lupeol (1), 7-methyljuglone (2), β-Sitosterol (3), stigmasterol (4) betulinic acid (5), diospyrin (6; DS) and 8-hydroxyisodiospyrin (7; HDS) which were hitherto unreported from D. lotus. The chloroform fraction (CFDL) and isolated compounds DS and HDS were evaluated for anti-nociceptive, sedative and anti-inflammatory effects. The acetic acid induced writing was significantly (p<0.001) protected by CFDL (72.43%), DS (40.87%) and HDS (65.76%) at higher doses which exhibited peripheral and central analgesic effects in acetic acid and hot-plat pain paradigms. Regarding the anti-inflammatory effect the CFDL (77.43%), DS (80.54%) and HDS (75.87%) protected the carrageenan paw edema after 3rd h. The central analgesic effect was significantly antagonized with naloxone (0.5 mg/kg), showing opiodergic mechanism of action. The CFDL, DS and HDS were also proved sedative in open field animal models. In acute toxicity study the chloroform fraction [CFDL (50, 100 and 150 mg/kg)], DS (5 and 10 mg/kg) and HDS (5 and 10 mg/kg) were found safe. Our study concluded that CFDL, DS and HDS have marked anti-nociceptive, anti-inflammatory and sedative effect. The anti-nociceptive and anti-inflammatory effects of the roots of D. lotus are partially attributed due to the presence of analgesic constituents like diospyrin (DS), 8-hydroxyisodiospyrin (HDS) and strongly supports the ethno-pharmacological uses of D. lotus as anti-nociceptive, anti-inflammatory and sedative.

Novel anti-nociceptive effects of cardamonin via blocking expression of cyclooxygenase-2 and transglutaminase-2

Recently, we reported that Alpinia katsumadai (AK) has anti-nociceptive activity in vivo and that cardamonin (CDN) from AK suppresses the activity and expression of transglutaminase-2 (Tgase-2). However, it remains unknown whether CDN contributes to the anti-nociceptive activities of AK in vivo. We examined the anti-inflammatory effects of CDN in MG63 osteoblast-like cells and Raw264.7 macrophage-like cells treated with interleukin-1β treatment. CDN suppressed the expression of Tgase-2, cyclooxygenase-2 (COX-2), and p65 (nuclear factor-κB) in a concentration-dependent manner, and restored the expression of IκB in MG63 and Raw264.7 cells. However, CDN did not inhibit the activity of COX-2. Gene silencing of Tgase-2 reduced the COX-2 expression in MG63 cells. Phenylbenzoquinone (PBQ)-induced writhing, carrageenan-induced hyperalgesia, and rota-rod test were used to evaluate the anti-nociceptive activity in vivo. CDN (3-30 mg/kg, orally administered) significantly inhibited PBQ-induced writhing. CDN also produced a significant, dose-dependent increase in the withdrawal response latencies in carrageenan-induced hyperalgesia. The effects of CDN on PBQ-induced writhing were not caused by impaired motor functions. These results suggest that CDN might be helpful in controlling the pain from inflammatory diseases.

Evaluation of Anti-Inflammatory and Anti-Nociceptive Effects of Defatted Fruit Extract of Olea europaea

Fruits of Olea europaea L. have been used for centuries in folk medicine to treat many inflammatory diseases. In order to evaluate the anti-nociceptive activities of the methanolic and aqueous extracts of defatted fruits of O. europaea, formalin test was used and for evaluation of anti-inflammatory effects of the extract, the volume of paw edema was measured. The results revealed that both extracts did not exhibit significant analgesic activity in the first phase of formalin test, whereas methanolic extract at the 600 mg/Kg dose and aqueous extract at the 450 and 600 mg/Kg doses could inhibit induced pain in the second phase of formalin test. Furthermore, the results of paw edema volume measurement indicated that the aqueous extract has anti-inflammatory effects at dose of 600 mg/Kg. Induced anti-nociception by aqueous olive extract was not reversed by naloxone, which indicates that the opioid receptors are not involved in the analgesic effects of the extracts. The present data pointed out that the extracts of olive defatted fruit have anti-nociceptive and anti-inflammatory effects in rats but further studies are needed to elucidate the mechanism(s) of action and active components which are involved in analgesic and anti-inflammatory effects.

and Erycibe schmidtii Craib

ETHNOPHARMACOLOGICAL RELEVANCE

Erycibe obtusifolia and Erycibe schmidtii, which belong to the same genus as Erycibe, are widely used in traditional medicine for the treatment of joint pain and rheumatoid arthritis (RA). Porana sinensis has become a widely used substitute for Erycibe obtusifolia and Erycibe schmidtii as they have declined in the wild. In the present work, the content of the main active components, the acute toxicity, the anti-nociceptive and anti-inflammatory activities of Porana sinensis, Erycibe obtusifolia and Erycibe schmidtii were compared, and the mechanisms of anti-nociceptive and anti-inflammatory activities were discussed.

MATERIALS AND METHODS

A quantitative HPLC (high performance liquid chromatography) method was first developed to compare the content of the main active components (scopoletin, scopolin and chlorogenic acid). The anti-inflammatory and anti-nociceptive activities of 40% ethanolic extracts of the three plants were compared using the models of xylene-induced ear edema, formalin-induced inflammation, carrageenan-induced air pouch inflammation, acetic acid-induced writhing and formalin-induced nociception. The acute toxicity of the 40% ethanolic extracts of the three plants was studied.

RESULTS

The assay suggested a large content of scopoletin, scopolin and chlorogenic acid in the three plants. The 40% ethanolic extracts of the three plants were almost non-toxic at the dose of 5g/kg and all of them showed significant anti-inflammatory effects in the tests of xylene-induced ear edema and formalin-induced inflammation. In the carrageenan-induced air pouch inflammation test, the synthesis of PGE2 was significantly inhibited by all the extracts. They significantly inhibited the number of contortions induced by acetic acid and the second phase of the formalin-induced licking response. Naloxone was not able to reverse the analgesic effect of these extracts.

CONCLUSION

The study identifies the similarity of the three plants in their main active components as well as acute toxicity, anti-nociceptive and anti-inflammatory activities. It supports the use of Porana sinensis as a suitable substitute, but further studies are needed to confirm this.

Challenging the catechism of therapeutics for chronic neuropathic pain: Targeting CaV2.2 interactions with CRMP2 peptides

Chronic neuropathic pain management is a worldwide concern. Pharmaceutical companies globally have historically targeted ion channels as the therapeutic catechism with many blockbuster successes. Remarkably, no new pain therapeutic has been approved by European or American regulatory agencies over the last decade. This article will provide an overview of an alternative approach to ion channel drug discovery: targeting regulators of ion channels, specifically focusing on voltage-gated calcium channels. We will highlight the discovery of an anti-nociceptive peptide derived from a novel calcium channel interacting partner - the collapsin response mediator protein 2 (CRMP2). In vivo administration of this peptide reduces pain behavior in a number of models of neuropathic pain without affecting sympathetic-associated cardiovascular activity, memory retrieval, sensorimotor function, or depression. A CRMP2-derived peptide analgesic, with restricted access to the CNS, represents a completely novel approach to the treatment of severe pain with an improved safety profile. As peptides now represent one of the fastest growing classes of new drugs, it is expected that peptide targeting of protein interactions within the calcium channel complex may be a paradigm shift in ion channel drug discovery.

Phytochemical Screening and Anti-nociceptive Properties of the Ethanolic Leaf Extract of Trema Cannabina Lour

PURPOSE

The present study was designed to investigate the anti-nociceptive activity of ethanolic leaf extract of Trema cannabina Lour (family: Cannabaceae) in experimental animal models.

METHODS

The anti-nociceptive action was carried out against two types of noxious stimuli, thermal (hot plate and tail immersion tests) and chemical (acetic acid-induced writhing) in mice.

RESULTS

Phytochemical analysis of crude extract indicated the presence of reducing sugar, tannins, steroid and alkaloid types of secondary metabolites. Crude extract of T. cannabina (500 mg/kg dose) showed maximum time needed for the response against thermal stimuli (6.79±0.15 seconds) which is comparable to diclofenac sodium (8.26±0.14 seconds) in the hot plate test. Hot tail immersion test also showed similar results as in hot plate test. At the dose of 250 and 500 mg/kg body weight, the extract showed significantly and in a dose-dependent (p<0.001) reduction in acetic acid induced writhing in mice with a maximum effect of 47.56% reduction at 500 mg/kg dose comparable to that of diclofenac sodium (67.07%) at 25 mg/kg.

CONCLUSION

The obtained results tend to suggest the Anti-nociceptive activity of ethanolic leaf extract of Trema cannabina and thus provide the scientific basis for the traditional uses of this plant part as a remedy for pain.

Ling and Scutellaria baicalensis Georgi

The study aimed to compare the anti-inflammatory and anti-nociceptive activities of Curcuma wenyujin Y.H. Chen et C. Ling (Curcuma wenyujin) and Scutellaria baicalensis Georgi (Scutellaria baicalensis). This study used three parts to compare the two herbs. Firstly, animals were randomly divided into a Scutellaria baicalensis group, a Curcuma wenyujin group, an indomethacin group, and a model-control group to perform an ear edema test, a carrageenin-induced paw edema test, a cotton pellet-induced granuloma formation test, and an acetic acid-induced writhing test. Secondly, model rats with pelvic inflammation were established, and the serum levels of TNF-α and IL-6 in each group was detected with the Enzyme-Linked Immunosorbent Assay (ELISA). Thirdly, pharmacokinetics analysis of Scutellaria baicalensis and Curcuma wenyujin was conducted on the model rats. The ear edema test, carrageenin-induced paw edema test, cotton pellet-induced granuloma formation test, and acetic acid-induced writhing test all showed that Curcuma wenyujin had stronger anti-inflammatory and anti-nociceptive effects than Scutellaria baicalensis. There is significant difference between the effects of Curcuma wenyujin and Scutellaria baicalensis on the levels of TNF-α and IL-6 for the model rats. Curcuma wenyujin decreased the levels of TNF-α and IL-6 more than Scutellaria baicalensis. The pharmacokinetics analysis showed that curcumol's Tmax, Cmax, and the area under the curve (AUC) were all higher than baicalin's. This study indicated that for pelvic inflammation, Curcuma wenyujin had better anti-inflammatory and anti-nociceptive effects than Scutellaria baicalensis.

A study of acute and chronic anti-nociceptive and anti-inflammatory effects of thiamine in mice

BACKGROUND

Thiamine (VitB1) is a vitamin with various important physiological functions and postulated therapeutic effects. Its use as an analgesic in neuropathic pain has been undergoing in clinical settings. However, there has been little experimental investigation on this effect. In this study, anti-nociceptive and anti-inflammatory effects of thiamine were investigated in mice.

METHODS

Three doses of thiamine (50, 100 and 125 mg/kg) were used by intraperitoneal injection in this study. Acute and chronic anti-nociceptive effects were examined using hot plate test alone and after sciatic nerve ligation, respectively. Imipramine (40 mg/kg) was used as positive control. Anti-inflammatory effects of thiamine on acute and chronic inflammation were assessed using xylene-induced edema in ears and granuloma caused by compressed cotton implantation, respectively. Sodium diclofenac (15 mg/kg) was used as positive control. Open field test was performed to differentiate the mice responses in the acute anti-nociceptive tests.

RESULTS

All three doses of thiamine showed significant analgesic effects in non-ligated mice and also in neuropathic pain in ligated animals. Increasing the dose of thiamine correlated with a more pronounced and sustained effect. Acute anti-inflammatory investigation showed that thiamine injected 30 or 60 minutes before xylene application reduced the weight of edematic ears. However, the effect of thiamine was less pronounced than diclofenac. Furthermore, when injected once daily for 7 days, all doses of thiamine significantly reduced the weight of the cotton disks, showing suppression of granuloma formation.

CONCLUSION

Taken together, it has been shown that thiamine possesses remarkable analgesic activities and also has significant anti-inflammatory effects, confirming its clinical use in controlling pain and less in inflammation.