Thermal Models Of Nociception Research Articles

Chemical profile and biological properties of the essential oil of Thymus atlanticus (Ball) Roussine

Aromatic and medicinal plants are an important source of natural products, including essential oils. These volatile oils are endowed with large spectra of biological and pharmacological properties. The species of Thymus genus belonging to Lamiaceae family produce significant amounts of essential oils with high bioactivity. Thymus atlanticus (Ball) Roussine. (T. atlanticus) is an endemic thyme species that grows in the Moroccan High Atlas Mountains. T. atlanticus, along with other Thymus species, have numerous traditional uses and therapeutic applications in Morocco. Regardless, toxicity, antioxidant, analgesic, and anti-inflammatory properties of the essential oils of this thyme have never been studied before. In this paper, the chemical composition, acute toxicity, antioxidant, analgesic, and anti-inflammatory activities of T. atlanticus are investigated. The results of the chemical composition using GC/MS analysis showed that thymol (23.7%) and carvacrol (22.8%) are the major volatile constituents of this thyme. Moreover, the acute toxicity assessment showed that the essential oil of T. atlanticus is not toxic at 2 g/kg bw. In addition, the oil of this thyme has an important amount of phenolic compounds (6.06 GAE mg/g EO) and a good antioxidant activity (IC50 DPPH = 0.21 mg/ml). The analgesic tests showed that the volatile oil of this thyme induced analgesic effects, suggesting anti-nociceptive actions in both chemical and thermal models of nociception. In addition, T. atlanticus essential oil produced a significant anti-inflammatory effect, as demonstrated by inhibition of ear edema induced by phenol (% of edema was 19.39% for essential oil treatment group compared to 77.59% for edema control group). These findings provide support for the traditional use of T. atlanticus in the Moroccan High Atlas folk medicine. Further investigations are recommended for the possible development of natural antioxidant, analgesic, and anti-inflammatory products from the essential oils of T. atlanticus.

English

The present work concerns the analgesic effects of zerumbona, obtained from Zingiber zerumbet L. Smith cultivated in Manaus/Amazonas. The compound has been studied for decades because it has potent cytotoxic activity against liver and prostate tumor cells, colon, and breast. The plant is rich in sesquiterpenes, glycosylated flavonoids that present important pharmacological activities; standing out cytotoxic activity against neoplastic cells of cancers. The objective of this study was to test the antinociceptive activity of zerumbone (ZER) using chemical and thermal nociception models, that is, writhing test induced by acetic acid and hot plate test. ZER administered orally and intraperitoneally produced significant and dose-dependent analgesic activity against the pain, acetic acid, formalin, and capsaicin models. In addition, ZER significantly increased the dormancy of the animals in the hotplate test pain model (49-540C). It was demonstrated that intraperitoneal (i.p.) and oral (p.o.) administration of ZER sesquiterpene in doses of 150 to 500 mg/kg i.p. and 250 to 1500 mg/kg p.o. produced significant dose-dependent inhibition of acetic acid-induced abdominal writhing, as compared to fentanest (20 µg/kg). At the same intraperitoneally and orally doses, the ZER produced significant dose-dependent latency-time increases in the hot-plate test relative to control. It was concluded that ZER exhibits both central and peripheral antinociceptive activity, indicating it to hold therapeutic potential for the discovery of new antinociceptive drugs as an alternative for the discovery of new drugs in the control of neurogenesi. The ZER exhibited similar efficacy and strength via both oral and intraperitoneally routes. ZER is the major essential oil component, a new sesquiterpene responsible for its nociceptive effect, when compared with other antinociceptive sesquiterpenes described in literature. Key words: Zingiber zerumbet, zerumbone, Zingiberacea, antinociceptive activity.   &nbsp

Antinociceptive Effects of Cardamonin in Mice: Possible Involvement of TRPV₁, Glutamate, and Opioid Receptors.

Pain is one of the most common cause for hospital visits. It plays an important role in inflammation and serves as a warning sign to avoid further injury. Analgesics are used to manage pain and provide comfort to patients. However, prolonged usage of pain treatments like opioids and NSAIDs are accompanied with undesirable side effects. Therefore, research to identify novel compounds that produce analgesia with lesser side effects are necessary. The present study investigated the antinociceptive potentials of a natural compound, cardamonin, isolated from Boesenbergia rotunda (L) Mansf. using chemical and thermal models of nociception. Our findings showed that intraperitoneal and oral administration of cardamonin (0.3, 1, 3, and 10 mg/kg) produced significant and dose-dependent inhibition of pain in abdominal writhing responses induced by acetic acid. The present study also demonstrated that cardamonin produced significant analgesia in formalin-, capsaicin-, and glutamate-induced paw licking tests. In the thermal-induced nociception model, cardamonin exhibited significant increase in response latency time of animals subjected to hot-plate thermal stimuli. The rota-rod assessment confirmed that the antinociceptive activities elicited by cardamonin was not related to muscle relaxant or sedative effects of the compound. In conclusion, the present findings showed that cardamonin exerted significant peripheral and central antinociception through chemical- and thermal-induced nociception in mice through the involvement of TRPV1, glutamate, and opioid receptors.

Analgesic Effect of 5-(3,4-Dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one in Experimental Animal Models of Nociception

Curcuminoids derived from turmeric rhizome have been reported to exhibit antinociceptive, antioxidant and anti-inflammatory activities. We evaluated the peripheral and central antinociceptive activities of 5-(3,4-dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one (DHHPD), a novel synthetic curcuminoid analogue at 0.1, 0.3, 1 and 3 mg/kg (intraperitoneal), through chemical and thermal models of nociception. The effects of DHHPD on the vanilloid and glutamatergic systems were evaluated through the capsaicin- and glutamate-induced paw licking tests. Results showed that DHHPD significantly (p < 0.05) attenuated the writhing response produced by the 0.8% acetic acid injection. In addition, 1 and 3 mg/kg of DHHPD significantly (p < 0.05) reduced the licking time spent by each mouse in both phases of the 2.5% formalin test and increased the response latency of mice on the hot-plate. However, the effect produced in the latter was not reversed by naloxone, a non-selective opioid receptor antagonist. Despite this, DHHPD decreased the licking latency of mice in the capsaicin- and glutamate-induced paw licking tests in a dose response manner. In conclusion, DHHPD showed excellent peripheral and central antinociceptive activities possibly by attenuation of the synthesis and/or release of pro-inflammatory mediators in addition to modulation of the vanilloid and glutamatergic systems without an apparent effect on the opioidergic system.

New \u03b2N-octadecanoyl-5-hydroxytryptamide: antinociceptive effect and possible mechanism of action in mice

The present study examined the potential antinociceptive activity of C18 5-HT (βN-octadecanoyl-5-hydroxytryptamide) using chemical and thermal nociception models in mice. Orally administered C18 5-HT (0.1, 1 and 10 mg/kg) produced significant dose-dependent antinociceptive effects in formalin-, capsaicin- and glutamate-induced licking models. This compound also induced a significant increase in the response to thermal stimuli in the hot plate test, and its antinociceptive effect was not related to muscle relaxant or sedative actions. In a thermal hyperalgesia model, C18 5-HT presented an anti-hyperalgesic profile as evidenced by the increase in the response time of the animals. Furthermore, intraperitoneal (i.p) pretreatment with naloxone (a non-selective opioid receptor antagonist, 1 mg/kg), ondansetron (serotoninergic receptor antagonist (5-HT3 subtype), 0.5 mg/kg) or AM241 (CB1 cannabinoid receptor antagonist, 1 mg/kg) reversed the antinociceptive effects of C18 5-HT in the hot plate model. In the formalin-induced licking model, pretreatment with naloxone reversed the antinociceptive effects of C18 5-HT, as demonstrated by an increase in the paw licking response when compared with the C18 5-HT-treated group. These findings suggest that C18 5-HT has peripheral and central antinociceptive effects and that its mechanism of action involves, ate least in part, opioid, serotoninergic and cannabinoid pathways.

Impact of Croton argyrophyllus essential oil on behavioural models of nociception

AbstractCroton argyrophyllus Kunth (Euphorbiaceae) is a shrub abundant in the northeast region of Brazil where it possesses ethnobotanical use. To assess the antinociceptive action of C. argyrophyllus, studies were conducted in behavioural models of nociception, and some of the mechanisms given under this effect investigated. The essential oil (EO) of C. argyrophyllus leaves (10, 30 and 100 mg/kg) was used in mice via the oral route in both the chemicals (acetic acid, formalin, capsaicin and glutamate) and thermal nociception models. The EO produced inhibition of acetic acid‐induced visceral pain (10, 30 and 100 mg/kg, p.o.) and it produced a significant antinociception effect in the hot plate test (100 mg/kg). In the formalin test, the EO caused significant inhibition of both the early (100 mg/kg) and the late (30 and 100 mg/kg) phases of formalin‐induced licking. The EO (30 and 100 mg/kg) also caused significant inhibition of capsaicin‐ and glutamate‐induced pain. The EO (100 mg/kg) antinociception in the hot plate test was significantly attenuated by treatment with naloxone. In contrast, the EO (100 mg/kg) antinociception in the abdominal constriction test was not affected by treatment of mice with L‐arginine. The present results suggest that the EO from C. argyrophyllus produced antinociception in several models of pain in mechanisms that involved glutamatergic and opioid systems. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Pregabalin enhances the antinociceptive effect of oxycodone and morphine in thermal models of nociception in the rat without any pharmacokinetic interactions.

Oxycodone is increasingly being used in combination with pregabalin. Pregabalin use is prevalent in opioid-dependent individuals. A high number of deaths caused by the co-use of gabapentinoids and opioids occur. It is not known whether pregabalin affects concentrations of oxycodone or morphine in the central nervous system. Effects of pregabalin on acute oxycodone or morphine-induced antinociception, tolerance and sedation were studied using tail-flick, hot plate and rotarod tests in male Sprague-Dawley rats. Concentrations of pregabalin, opioids and their major metabolites in the brain were quantified by mass spectrometry. In the hot plate test, morphine (2.5 mg/kg, s.c.) caused antinociception of 28% maximum possible effect (MPE), whereas pregabalin (50 mg/kg, i.p.) produced 8-10% MPE. Co-administration of pregabalin and morphine resulted in antinociception of 63% MPE. Oxycodone (0.6 mg/kg s.c.) produced antinociception of 18% MPE, which increased to 39% MPE after co-administration with pregabalin. When pregabalin 10 mg/kg was administered before oxycodone (0.6 mg/kg, s.c.) or morphine (2.5 mg/kg), only the effect of oxycodone was potentiated in the tail-flick and the hot plate tests. Brain concentrations of the opioids, their major metabolites and pregabalin were unchanged. Pregabalin co-administration (50 mg/kg, i.p., once daily) did not prevent the development of morphine tolerance. Pregabalin potentiated antinociceptive and sedative effects of oxycodone and morphine in acute nociception. Co-administration of pregabalin with the opioids did not affect the brain concentrations of oxycodone or morphine. Pregabalin did not prevent morphine tolerance.

Analgesic and free radical scavenging activities of hydromethanolic extract of Crateva adansonii stem bark

Background:Crateva adansonii is a moderately sized deciduous tree found throughout the tropics especially along the river banks. This study was aimed at the evaluation of the analgesic and antioxidant activities of the methanolic extract of C. adansonii stem-bark.Methods:The analgesic activity of Crateva extract was investigated using both chemical and thermal models of nociception in rodents while the antioxidant activity was evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) photometric model.Results:The extract produced a minute concentration-dependent increase in free radical scavenging activities. The extract (100, 200, and 400 mg/kg) caused a significant (P < 0.05) dose-dependent reduction in the number of writhing in treated rats when compared to the negative control. The extract at 100, 200, 400 mg/kg, and pentazocine (3 mg/kg) increased the pain reaction time in the treated rats by 58.05%, 66.67%, 94.76%, and 79.40%, respectively, when compared to the negative control.Conclusion:The C. adansonii stem bark possesses analgesic activity against peripheral and central mediated pain sensation and also antioxidant properties. This study justifies the ethnomedical use of C. adansonii in pain treatment.

Assessment of mechanisms involved in antinociception produced by the alkaloid caulerpine.

In previous works we showed that oral administration of caulerpine, a bisindole alkaloid isolated from algae of the genus Caulerpa, produced antinociception when assessed in chemical and thermal models of nociception. In this study, we evaluated the possible mechanism of action of this alkaloid in mice, using the writhing test. The antinociceptive effect of caulerpine was not affected by intraperitoneal (i.p.) pretreatment of mice with naloxone, flumazenil, l-arginine or atropine, thus discounting the involvement of the opioid, GABAergic, l-arginine-nitric oxide and (muscarinic) cholinergic pathways, respectively. In contrast, i.p. pretreatment with yohimbine, an α2-adrenoceptor antagonist, or tropisetron, a 5-HT3 antagonist, significantly blocked caulerpine-induced antinociception. These results suggest that caulerpine exerts its antinociceptive effect in the writhing test via pathways involving α2-adrenoceptors and 5-HT3 receptors. In summary, this alkaloid could be of interest in the development of new dual-action analgesic drugs.

Isolation of a dihydrobenzofuran lignan, icariside E4, with an antinociceptive effect from Tabebuia roseo-alba (Ridley) Sandwith (Bignoniaceae) bark.

The antinociceptive activity of icariside E4, a dihydrobenzofuran-type lignan isolated from Tabebuia roseo-alba (Ridley) Sandwith (Bignoniaceae) bark, was evaluated in mice by using chemical and thermal models of nociception. Intraperitoneal (i.p.) administration of crude T. roseo-alba bark extract and its methanol fraction inhibited acetic acid-induced abdominal constriction in mice. Furthermore, i.p. administration of 0.1, 1, and 10 mg/kg of icariside E4 reduced the number of writhes evoked by acetic acid injection by 46.9, 82.3, and 66.6%, respectively. Icariside E4 administration had no effect in the first phase of the formalin test, but it reduced nociceptive behavior in the second phase as indicated by a reduction in the licking time. Icariside E4 did not modify thermal nociception in the hot-plate test model, suggesting that it had a peripheral antinociceptive action. The antinociceptive effect of icariside E4 in the writhing test was reversed by pre-administration of glibenclamide, but not of naloxone, atropine, yohimbine, or haloperidol. Together, these results indicated that the antinociceptive activity of icariside E4 from T. roseo-alba in models of chemical pain occurred through ATP-sensitive K(+) channel-dependent mechanisms.

Antinociceptive effect of Encholirium spectabile: A Bromeliaceae from the Brazilian caatinga biome.

Background:Encholirium spectabile is a species found in outcrops rocky throughout the Brazilian Caatinga.Objective:This study was carried out to evaluate the antinociceptive effects of ethanolic extract of the leaves from E. spectabile (Es-EtOH) in mice using chemical and thermal models of nociception.Material and Methods:HPLC was used to determine the fingerprint chromatogram. The Es-EtOH was examined for its antinociceptive activity at the doses of 100, 200 and 400 mg/kg intraperitoneal (i.p.). The evaluation of antinociceptive activity was carried out by the acetic acid-induced writhing, formalin and hot plate tests in mice. Rota-rod test was used for the evaluation of motor coordination.Results:In the acetic acid-induced writhing test, the Es-EtOH (100, 200 and 400 mg/kg, i.p.) reduced the number of writhings by 68.59, 79.33 and 65.28%, respectively. Additionally, Es-EtOH (100, 200 and 400 mg/kg, i.p.) decreased by 34.14, 52.61 and 60.97% the paw licking time in the first phase, as well as 89.56, 79.90 and 96.71% in the second phase of the formalin test, respectively. Es-EtOH also showed effect in the hot plate test, since increased the latency time at dose of 100 mg/kg after 60 minutes. In addition, Es-EtOH did not impair motor coordination. The presence of phenolic compounds in the extract was confirmed using HPLC. These results indicate that Es-EtOH has antinociceptive activity, probably of peripheral origin. The mechanism involved is not completely understood but, at least in part there is the participation of opioid receptors.

Libidibia ferrea mature seeds promote antinociceptive effect by peripheral and central pathway: possible involvement of opioid and cholinergic receptors.

Libidibia ferrea (LF) is a medicinal plant that holds many pharmacological properties. We evaluated the antinociceptive effect in the LF aqueous seed extract and Lipidic Portion of Libidibia ferrea (LPLF), partially elucidating their mechanisms. Histochemical tests and Gas chromatography of the LPLF were performed to characterize its fatty acids. Acetic acid-induced abdominal constriction, formalin-induced pain, and hot-plate test in mice were employed in the study. In all experiments, aqueous extract or LPLF was administered systemically at the doses of 1, 5, and 10 mg/kg. LF aqueous seed extract and LPLF demonstrated a dose-dependent antinociceptive effect in all tests indicating both peripheral anti-inflammatory and central analgesia properties. Also, the use of atropine (5 mg/kg), naloxone (5 mg/kg) in the abdominal writhing test was able to reverse the antinociceptive effect of the LPLF, indicating that at least one of LF lipids components is responsible for the dose related antinociceptive action in chemical and thermal models of nociception in mice. Together, the present results suggested that Libidibia ferrea induced antinociceptive activity is possibly related to its ability to inhibit opioid, cholinergic receptors, and cyclooxygenase-2 pathway, since its main component, linoleic acid, has been demonstrated to produce such effect in previous studies.

Antinociceptive and Antioxidant Activities of Phytol In Vivo and In Vitro Models.

The objective of the present study was to evaluate the antinociceptive effects of phytol using chemical and thermal models of nociception in mice and to assess its antioxidant effects in vitro. Phytol was administered intraperitoneally (i.p.) to mice at doses of 25, 50, 100, and 200 mg/kg. In the acetic acid-induced writhing test, phytol significantly reduced the number of contortions compared to the control group (P < 0.001). In the formalin test, phytol reduced significantly the amount of time spent in paw licking in both phases (the neurogenic and inflammatory phases), this effect being more pronounced in the second phase (P < 0.001). Phytol also provoked a significant increase in latency in the hot plate test. These antinociceptive effects did not impaire the motor performance, as shown in the rotarod test. Phytol demonstrated a strong antioxidant effect in vitro in its capacity to remove hydroxyl radicals and nitric oxide as well as to prevent the formation of thiobarbituric acid reactive substances (TBARS). Taken as a whole, these results show the pronounced antinociceptive effects of phytol in the nociception models used, both through its central and peripheral actions, but also its antioxidant properties demonstrated in the in vitro methods used.

Antinociceptive activity of Rhoifoline A from the ethanol extract of Zanthoxylum nitidum in mice

Aim of the studyAntinociceptive activity of Rhoifoline A (RA), a benzophenanthridine alkaloid obtained from the ethanol extract of Zanthoxylum nitidum, was evaluated in mice using chemical and thermal models of nociception. Materials and methodsRA was evaluated on anti-nociceptive activity in mice using chemical and thermal models of nociception. ResultsRA administered intraperitoneally at doses of 10, 20, 40 and 80mg/kg exhibited significant inhibitions on chemical nociception induced by intraperitoneal acetic acid and subplantar formalin, and on thermal nociception in the tail-flick test and the hot plate test. RA neither significantly impaired motor coordination in the rotarod test nor did spontaneous locomotion in the open-field test. RA did not enhance the pentobarbital sodium induced sleep time. These results indicated that the observed antinociceptive activity of RA was unrelated to sedation or motor abnormality. Core body temperature measurement showed that RA did not affect temperature during a 2-hour period. Furthermore, RA-induced antinociception in the hot plate test was insensitive to naloxone or glibenclamide but significantly antagonized by L-NAME, methylene blue and nimodipine. ConclusionsTherefore, it is reasonable that the analgesic mechanism of RA possibly involved the NO-cGMP signaling pathway and L-type Ca2+ channels.

In vitro binding affinities of a series of flavonoids for μ-opioid receptors. Antinociceptive effect of the synthetic flavonoid 3,3-dibromoflavanone in mice

The pharmacotherapy for the treatment of pain is an active area of investigation. There are effective drugs to treat this problem, but there is also a need to find alternative treatments free of undesirable side effects. In the present work the capacity of a series of flavonoids to bind to the μ opioid receptor was evaluated. The most active compound, 3,3-dibromoflavanone (31), a synthetic flavonoid, presented a significant inhibition of the binding of the selective μ opioid ligand [3H]DAMGO, with a Ki of 0.846 ± 0.263 μM. Flavanone 31 was further synthesized using a simple and cheap procedure with good yield. Its in vivo effects in mice, after acute treatments, were studied using antinociceptive and behavioral assays. It showed no sedative, anxiolytic, motor incoordination effects or inhibition of the gastrointestinal transit in mice at the doses tested. It evidenced antinociceptive activity on the acetic acid-induced nociception, hot plate and formalin tests (at 10 mg/kg and 30 mg/kg). The results showed that the 5-HT2 receptor and the adrenoceptors seem unlikely to be involved in its antinociceptive effects. Naltrexone, a nonselective opioid receptors antagonist, totally blocked compound 31 antinociceptive effects on the hot plate test, but naltrindole (δ opioid antagonist) and nor-binaltorphimine (κ opioid antagonist) did not. These findings demonstrated that 3,3-dibromoflavanone (31), at doses that did not interfere with the motor performance, exerted clear dose dependent antinociception when assessed in the chemical and thermal models of nociception in mice and it seems that its action is related to the activation of the μ opioid receptor.

Involvement of spinal 5-HT1A receptors in isolation rearing-induced hypoalgesia in mice

Isolation rearing in rodents causes not only abnormal behaviors which resemble the clinical symptoms of schizophrenia but also hypoalgesia in thermal nociception models. However, the mechanism of the hypoalgesia is not known. The present study investigated the effect of isolation rearing on acute pain and the descending pain inhibitory pathways in mice. Rearing in isolation for 6weeks from post-weaning reduced pain sensitivity in the hot plate test and acetic acid-induced writhing test. Isolation rearing also reduced the intraplantar capsaicin-induced licking behavior. Capsaicin increased c-Fos expression, a neuronal activity marker, in the spinal cord and primary somatosensory cortex both in group- and isolation-reared mice, but this effect did not differ between groups. On the other hand, c-Fos expression in the anterior cingulate cortex, periaqueductal gray matter, and rostral ventromedial medulla, but not in the spinal cord or somatosensory cortex, was enhanced by isolation rearing. Systemic administration of WAY100635 (serotonin (5-HT)1A receptor antagonist), but not of ketanserin (5-HT2 receptor antagonist), prazosin (α1-adrenoceptor antagonist), or yohimbine (α2-adrenoceptor antagonist), attenuated isolation rearing-induced hypoalgesia in capsaicin-induced licking behavior. Attenuation of isolation rearing-induced hypoalgesia was also observed following the intrathecal injection of WAY100635. Naloxone, an opioid receptor antagonist, did not affect the hypoalgesia in isolation-reared mice. These findings suggest that isolation rearing causes hypoalgesia in mouse models of acute pain and imply that the spinal 5-HT1A receptor activation probably through descending serotonergic inhibitory pathway is involved in isolation rearing-induced hypoalgesia.

Antinociceptive effect of ethanolic extract of Selaginella convoluta in mice

BackgroundSelaginella convoluta (Arn.) Spring (Selaginellaceae), commonly known as “jericó”, is a medicinal plant found in northeastern Brazil. S. convoluta is used in folk medicine as an antidepressant, aphrodisiac, diuretic, analgesic, anti-inflammatory and it is used to combat amenorrhea, coughing and bleeding. This study was performed to evaluate the antinociceptive effects of ethanolic extract from S. convoluta in mice exposed to chemical and thermal models of nociception.MethodsPreliminary phytochemical analysis of the ethanolic extract was performed. The ethanolic extract from Selaginella convoluta (Sc-EtOH) was examined for its intraperitoneal (i.p.) antinociceptive activity at the doses of 100, 200 and 400 mg/kg body weight. Acetic acid-induced writhing, formalin injection and hot plate tests were used to evaluate the antinociceptive activity of Sc-EtOH extract. The rota-rod test was used to evaluate motor coordination.ResultsA preliminary analysis of Sc-EtOH revealed that it contained phenols, steroids, terpenoids and flavonoids. In the acetic acid-induced writhing test, mice treated with Sc-EtOH (100, 200 and 400 mg/kg, i.p.) exhibited reduced writhing (58.46, 75.63 and 82.23%, respectively). Secondly, Sc-EtOH treatment (100, 200 and 400 mg/kg, i.p.) decreased the paw licking time in mice during the first phase of the formalin test (by 44.90, 33.33 and 34.16%, respectively), as well as during the second phase of the test (by 86.44, 56.20 and 94.95%, respectively). Additionally, Sc-EtOH treatment at doses of 200 and 400 mg/kg increased the latency time in the hot plate test after 60 and 90 minutes, respectively. In addition, Sc-EtOH did not impair motor coordination.ConclusionOverall, these results indicate that Sc-EtOH is effective as an analgesic agent in various pain models. The activity of Sc-EtOH is most likely mediated via the inhibition of peripheral mediators and central inhibitory mechanisms. This study supports previous claims of traditional uses for S. convoluta.

Anti-Inflammatory and Analgesic Activity of Total Flavone of Cunninghamia lanceolata

The present study was undertaken to investigate the anti-inflammatory and analgesic activity of total flavone of branches and leaves of Cunninghamia lanceolata (TFC) to provide a scientific basis for its clinical use and resource development. TFC was evaluated for anti-inflammatory and analgesic activity in mice or rats using chemical and thermal models of nociception, including acetic acid-induced writhing test, hot plate latency test, formalin test and carrageenan induced paw oedema test. Results showed that TFC given orally can significantly attenuate acetic acid-induced writhing in mice in a dose-dependent manner. In the hot plate latency test, TFC showed common activity in prolonging duration time only at the highest dose (400 mg/kg). Each dose of TFC could not significantly inhibit the first phase but was active in the later phase of formalin-induced pain, whereas morphine showed notable activity in the two phases. In the carrageenan-induced paw oedema model, TFC could significantly and dose-dependently reduce the carrageenan-induced paw edema at the third and fifth hour, and decrease the content of PEG2 in paw edema tissue and that of COX-2 in blood serum. It may be concluded that TFC showed both anti-inflammatory and analgesic effects, showing that it can be of importance in drug development, especially in the field of pain and inflammation.

The analgesic activity and possible mechanisms of deacetyl asperulosidic acid methyl ester from Ji shi teng in mice

Deacetyl Asperulosidic Acid Methyl Ester (DAAME) from Ji shi teng was evaluated on analgesic activity in mice using chemical and thermal models of nociception. Given intraperitoneally, DAAME, at doses of 40 and 80mg/kg, produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid, subplantar formalin/capsaicin injections and on thermal nociception in the tail-flick test and in the hot plate test. In the open-field test and the rotarod test, DAAME couldn't impair the motor performance, indicating that the observed antinociception was unlikely due to motor abnormality. In a measurement of core body temperature, DAAME (80mg/kg) did not affect temperature within 80min. Moreover, DAAME-induced antinociception in the capsaicin test and the hot plate test was significantly antagonized by glibenclamide. The results suggested that DAAME-produced antinociception was possibly involved in the ATP sensitive K+ channels in the capsaicin test and the hot plate test, which merited exploring further.

Activity study of a hydroxynaphthoquinone fraction from Arnebia euchroma in experimental arthritis

Although various drugs for the treatment of rheumatoid arthritis (RA) have been used in clinics, RA is not completely curable to date. Thus, to seek new drugs for the treatment of RA has been a hotspot. Hydroxynaphthoquinones are the major anti-inflammatory active constituents in Arnebia euchroma (Royle) Johnst. The present study aims to evaluate the anti-arthritic activity of a hydroxynaphthoquinone mixture (HM) of A. euchroma (Royle) Johnst, including its anti-inflammatory and analgesic effects. The anti-arthritic efficacy of HM was examined using complete Freund's adjuvant- and bovine type II collagen-induced arthritic models. The paw edema, polyarthritis index and histopathological change were evaluated. The analgesic effect was assessed using the chemical and thermal models of nociception. Results found that HM administered prophylactically and curatively showed marked anti-arthritic activity by suppressing the paw swelling and development of inflammation, lowering the levels of TNF-α and IL-1β and protecting cartilage and bone from damage. The protection of HM was superior to that of reference drugs such as prednisone acetate or etanercept, and showed no direct deleterious effect. Similarly, HM showed significant analgesic effects. In summary, HM possessed potent anti-arthritic activity. It could relieve inflammatory symptoms and protect against joint destruction. These findings indicate that HM would be a potential therapeutic agent for arthritic disease, which provide pharmacological evidence for its clinical application.