Acetic Acid-induced Writhing Tests Research Articles

Antinociceptive activity of Ligusticum porteri preparations and compounds

Context: The roots and rhizomes of Ligusticum porteri Coulter & Rose (Apiaceae) are widely used in Mexican folk medicine for several purposes, including painful complaints.Objective: The main goal of this work was to demonstrate the analgesic action in mice of some preparations and major compounds from L. porteri.Materials and methods: The extracts, aqueous (AE) and organic (OE), the essential oil (EO) and major compounds (10–316 mg/kg) from L. porteri were evaluated as potential antinociceptive agents using the acetic acid-induced writhing and hot plate tests in ICR mice.Results: All preparations tested exhibited significant antinociceptive effect in the two animal pain models selected. AE and EO were more effective in the writhing test while OE had a better effect in the hot-plate model. On the other hand, Z-ligustilide (1) provoked an increment in the latency period to the thermal stimuli in the hot-plate test at a dose of 31.6 mg/kg, and a decrease in the number of abdominal writhes at 10 mg/kg. Z-3-butylidenephthalide (2) induced a dose-dependent antinociceptive action in the hot-plate assay; this compound was also effective for controlling the pain provoked by chemical irritation at the doses of 10 and 31.6 mg/kg. Finally, diligustilide (3) inhibited the number of writhing responses at all doses tested but was inactive in the hot-plate model.Conclusion: The present investigation provides in vivo evidence supporting the use of L. porteri to treat painful conditions in folk medicine.

Guava pomace: a new source of anti-inflammatory and analgesic bioactives

BackgroundGuava pomace is an example of the processing waste generated after the manufacturing process from the juice industry that could be a source of bioactives. Thus, the present investigation was carried out in order to evaluate the anti-inflammatory and antinociceptive potential and determinate the main phenolic compounds of a guava pomace extract (GPE).MethodsThe anti-inflammatory activity was evaluated by carrageenan, dextran, serotonin, histamine-induced paw edema and neutrophils migration in the peritoneal cavity models. Acetic acid-induced abdominal writhing and formalin test were performed to investigate the antinociceptive effects. In addition, the content of total phenolic and of individual phenolic compounds was determined by GC/MS.ResultsGPE showed anti-inflammatory activity by carrageenan, dextran, serotonin, histamine-induced paw edema and neutrophils migration in the peritoneal cavity models (p < 0.05). GPE also demonstrated antinociceptive activity by acetic acid-induced abdominal writhing and formalin test (p < 0.05). The total phenolic value was 3.40 ± 0.09 mg GAE/g and epicatechin, quercetin, myricetin, isovanilic and gallic acids were identified by GC/MS analysis.ConclusionsThe presence of bioactive phenolic compounds as well as important effects demonstrated in animal models suggest that guava pomace could be an interesting source of anti-inflammatory and analgesic substances.

Anti-nociceptive and anti-oedematogenic properties of the hydroethanolic extract of Sidastrum micranthum leaves in mice

Sidastrum micranthum (A. St.-Hil.) Fryxell, Malvaceae, grows in the northeastern region of Brazil, where the leaves of this species are traditionally used to treat coughs, bronchitis or asthma. Male Swiss mice (20-22g) were tested in models of acute pain (acetic acid-induced abdominal writhing, tail flick and formalin test), oedema assessment test (paw oedema test) and model for evaluation of spontaneous motor performance (open field test). The hydroethanolic extract of S. micranthum was administered orally at doses of 50–500mg/kg. In addition were administered water, vehicle, morphine 5.01mg/kg (evaluation of pain and motor performance) and dexamethasone 2.25mg/kg (evaluation of oedema formation). The extract showed a significant effect at all doses in the acetic acid-induced abdominal writhing test and at the second phase of the formalin test, while in the first phase of this test and in the paw oedema test only at the highest dose (500mg/kg). In the formalin and paw oedema tests, the extract had a potentiation of the anti-nociceptive and anti-inflammatory effects by pretreatment with L-NAME and reduction of the effect by pretreatment with L-arginine. The extract was not toxic after oral administration (LD50>2000mg/kg).

Aqueous root extracts from Mimosa albida Humb. & Bonpl. ex Willd display antinociceptive activity in mice

Ethnopharmacological relevanceIn this work, we study whether aqueous extracts from the roots of Mimosa albida Humb. & Bonpl. ex Willd, a plant known in the Highlands of Chiapas, Mexico as “Lotóm chíx” are endowed with both antinociceptive and anxiolytic effects. Materials and methodsICR mice were systemically treated with aqueous extracts from Mimosa albida and the reference compounds (diazepam, dipyrone and/or fentanyl) and their behavior was evaluated in several behavioral tests. ResultsAdministration of aqueous extracts from the roots of Mimosa albida resulted in a reduction of the nociception elicited in mice by both the hot plate (12.5, 25 and 50mg/kg; i.p.) and the acetic acid-induced writhing (25 and 50mg/kg; i.p.) tests. No effects were however observed both in the elevated plus-maze and hole board test (3.2, 12.5 and 25mg/kg; i.p.). In contrast, both locomotion (open field test) and motor coordination (rotarod test) were affected at doses (50, 100 y 200mg/kg; i.p.) higher than those having antinociceptive effects. ConclusionThese data suggest that in mice the systemic administration of low doses of aqueous extracts from the roots of Mimosa albida results in antinociceptive effects in several models of pain through mechanisms that do not involve the opioid system pathway. These results support the ethnopharmacological use of Mimosa albida in popular medicine.

Anti-inflammatory and antinociceptive effects of hydroalcoholic extract from Pseudobombax marginatum inner bark from caatinga potiguar

Ethnopharmacological relevanceThe Pseudobombax marginatum (St Hil) Rob., Malvaceae, is mentioned in ethnobotanical studies. It is used as anti-inflammatory, for ulcers and gastritis, and back pain. To evaluate anti-inflammatory and antinociceptive activities a hydroalcoholic extract (HE) from inner bark was prepared. Materials and methodsFor the anti-inflammatory activity, carrageenan-induced paw edema and peritonitis models, and also myeloperoxidase assay were used. For the antinociceptiva activity acetic acid-induced writhing, hot plate and formalin tests were employed. ResultsThe HE extract exhibited an intense inhibition in carrageenan-induced edema model and also in myeloperoxidase activity at the doses of 100 and 300mg/kg. The leukocyte migration into the peritoneal cavity was also inhibited at the doses of 30, 100 and 300mg/kg. A similar profile was observed against acid-induced abdominal contortions and in formalin second phase test at the doses of 30 and 100mg/kg, but this treatment did not affect the behavior of animals in the hot plate test. ConclusionsThe experimental data of the HE from Pseudobombax marginatum show anti-inflammatory and antinociceptiva activities, confirming the indication from traditional medicine; however further studies are required to define and isolate the active anti-inflammatory and antinociceptiva components from this active specie.

Antinociceptive Activity of Ligusticum porteri Preparations and Compounds

The roots and rhizomes of Ligusticum porteri are widely used in Mexican folk medicine for several purposes, including painful complaints. The objective of this work was to demonstrate the antinociceptive activity of some extracts and major compounds from L. porteri using the acetic acid-induced writhing and hot plate tests in ICR mice. All preparations tested exhibited significant antinociceptive effect in the two animal pain models selected. Z-ligustilide (1) provoked an increment in the latency period to the thermal stimuli in the hot-plate test at a dose of 31.6 mg/kg, and a decrease in the number of abdominal writhes at 10 mg/kg. Z-3-butylidenephthalide (2) induced a dose-dependent antinociceptive action in the hot-plate assay; this compound was also effective for controlling the pain provoked by chemical irritation at the doses of 10 and 31.6 mg/kg. Finally, diligustilide (3) inhibited the number of writhing responses at all doses tested but was inactive in the hot-plate model.

Leaf extract from Clusia nemorosa induces an antinociceptive effect in mice via a mechanism that is adrenergic systems dependent

Previous studies on the genus Clusia have shown anti-inflammatory and antiproliferative effects of the leaf extracts, but its antinociceptive activity has never been characterized. In the present study, the antinociceptive activity of the hexane extract of the leaves of Clusia nemorosa G. Mey, called HECn, was examined. Antinociceptive activity was evaluated using acetic acid-induced writhing, formalin, and hot-plate tests. All experiments were carried out on male Swiss mice. The extract (1-400 mg·kg−1), given by intraperitoneal route (i.p.) 1 h prior to testing, produced a dose-dependent inhibition on the number of abdominal writhings, with an ID50 of 62 mg·kg−1. In addition, HECn was able to prevent the visceral pain induced by acetic acid in mice for at least 2 h. In the formalin test, HECn had no effect in the first phase, but produced an analgesic effect on the second phase with the inhibition of licking time. The HECn did not show a significant analgesic effect in the hot plate test. Pretreatment with yohimbine attenuated the antinociceptive effect induced by HECn in the writhing test. However, naloxone, atropine, or haloperidol did not affect antinociception induced by HECn in the writhing test. Together, these results indicate that the extract from the leaves of Clusia nemorosa produces antinociception in models of chemical pain through mechanisms that suggest participation of the adrenergic systems pathway.

Antinociceptive and anti-inflammatory activities of an aqueous extract of Chiliotrichum diffusum

The flowers of the Chiliotrichum diffusum (G. Forst.) Kuntze, Asteraceae, have long been used in traditional medicine and rituals. In this study, the antiinfl ammatory and antinociceptive activities of a decoction of the flowers were evaluated and a phytochemical analysis was performed by HPLC-DAD. In order to evaluate the antinociceptive activity, the acetic acid-induced abdominal writhing and hot plate tests were used. The anti-inflammatory activity was evaluated using carrageenaninduced rat paw oedema. The decoction induced a signifi cant anti-inflammatory effect (inhibition of 56.0% at 3 h) and produced signifi cant inhibition on nociception in the acetic acid test (ED50 35mg/kg i.p.; ED50 709mg/kg p.o.). In the hot plate test, the antinociceptive activity of the extract employed at 500mg/kg i.p. was signifi cantly suppressed by pretreatment with naloxone (5mg/kg). HPLC analysis showed the presence of chlorogenic acid, caffeic acid, hyperoside, isoquercitrin, quercitrin, afzelin, quercetin, apigenin and kaempferol. The decoction of C. diffusum proved to have antinociceptive and anti-inflammatory effects that may be related to the presence of the flavones, flavonols and phenolic acids identifi ed. The opiod system seems to be involved in the mechanism of antinociception of the extract.

Analgesic effects of glycoproteins from Panax ginseng root in mice

Ethnopharmacological relevanceThe root of Panax ginseng C.A. Mey has various beneficial pharmacological effects. The present study aimed to evaluate the analgesic activities of glycoproteins from the root of Panax ginseng C.A. Mey in mice. Materials and methodsGlycoproteins were isolated and purified from the root of Panax ginseng C.A. Mey. Physicochemical properties and molecular mass were determined by chemical assay and HPLC. Acetic acid-induced writhing and hot-plate tests were employed to study the analgesic effect of glycoproteins and compared with that of aspirin or morphine. The locomotor activity was tested in mice by using actophometer. ResultsFour glycoproteins were obtained. The glycoproteins which protein content was the highest (73.04%) displayed dose-dependent analgesic effect. In writhing test, the glycoproteins significantly inhibited writhes (P<0.001) at the dose of 20mg/kg by intraperitoneal injection. In hot-plate test, only at the dose of 20mg/kg prolong the hot-plate latency (P<0.05, at 30min). In the locomotor activity test, the glycoproteins were significant decrease of motility counts at the dose of 20 and 40mg/kg. ConclusionThese findings collectively indicate that the glycoproteins from the root of Panax ginseng C.A. Mey exhibited significant analgesic activities and the proteins were the active site, providing evidence for its pharmacal use.

Studies on the antiinflammatory, antinociceptive and antimicrobial activities of Combretum calobotrys (Combretaceae) leaf

The methanol:dichloromethane extract of Combretum calobotrys Engl & Diels (Combretaceae) leaves (CCE) was subjected to solvent-guided fractionation to yield the hexane (HF), dichloromethane (DF) and methanol (MF) fractions. The anti-inflammatory effects of the extract and fractions were evaluated in rodents using xylene-induced topical ear edema, carrageenan-induced pedal edema, formaldehyde-induced arthritis and cotton pellet granuloma tests, respectively. The extract and fractions were screened for analgesic activity using acetic acid induced writhing and formalin test in rodents. They were subjected to antimicrobial assay and also analysed for phytochemical constituents, while the CCE was subjected to acute toxicity (Lethal dosage, LD50) test using standard procedures. The extract and fractions (200 and 400 mg/kg) significantly (P 5,000 mg/kg. The results indicate that C. calobotrys leaf possess anti-inflammatory, analgesic and antimicrobial activities. Key words: Combretum calobotrys, anti-inflammatory, analgesic, abdominal writhing, formalin test, agar dilution.

Antinociceptive, anti-inflammatory and antiulcerogenic activities of ethanol root extract of Strophanthus hispidus DC (Apocynaceae)

Strophanthus hispidus DC (Apocynaceae) is a medicinal plant widely used in traditional African medicine in the treatment of rheumatic afflictions, ulcer, conjunctivitis, leprosy and skin diseases. This study sought to investigate the antinociceptive, anti-inflammatory and antiulcer properties of the ethanol root extract of S. hispidus. Antinociceptive activity was evaluated using acetic acid-induced writhing and formalin tests in mice. The carrageenan- and egg albumin-induced rat paw edema tests were used to investigate the anti-inflammatory actions, whereas the antiulcer activity was investigated using ethanol-, HCl- and pyloric ligation-induced gastric ulcer models in rats. S. hispidus [100-800 mg/kg orally (po)] produced significant (p<0.05) inhibition of writhing reflex with peak effect of 74.13% inhibition observed at 800 mg/kg. Similarly, S. hispidus significantly (p<0.05) attenuated formalin-induced early and late phase of nociception with peak effect of 61.84% and 89.43%, respectively, at 200 mg/kg. S. hispidus (25-800 mg/kg po) caused significant (p<0.05) inhibition of edema development in the carrageenan and egg albumin models with peak effect (93.40% and 90.10% inhibition of edema formation) observed at 50 mg/kg. With respect to antiulcer activity, S. hispidus (100-800 mg/kg) showed potent antiulcer activity with respective peak effects of 96% (ethanol-induced), 99% (HCl-induced) and 70.60% inhibition of ulcer. The findings in this study suggest that the ethanol root extract of S. hispidus possesses antinociceptive, anti-inflammatory and antiulcerogenic activities. This justifies the use of the extract in folklore medicine for the treatment of ulcer and inflammatory disorders.

English

&nbsp; Cyphostemma vogelii&nbsp;(family: Vitaceae) is a herbaceous plant which grows in Obukpa town in South Eastern Nigeria.&nbsp;C. vogelii&nbsp;is said to be generally medicinal though no specific medicinal activity was mentioned in the literature for this plant. The analgesic effect of&nbsp;C. vogelii&nbsp;was evaluated using acetic acid-induced writhing and formalin-induced nociception tests. The extract was also screened for anti-inflammatory activity using carrageenan-induced and kaolin-carrageenan-induced paw edema tests.&nbsp;C. vogelii&nbsp;extract dose dependently inhibited acetic acid-induced pain in mice. The extract at 200 and 400 mg/kg significantly inhibited inflammatory and neurogenic pain induced by formalin. The effects of 200 mg/kg on formalin induced pain were similar to those of aspirin, while 400 mg/kg produced more inhibitory effects. At 2, 3 and 5 h post carrageenan injection, 200 and 400 mg/kg extract significantly inhibited paw edema.&nbsp;The extract dose dependently suppressed kaolin-carrageenan-induced edema from 3 h post treatment for up to 24 h. The effect of 400 mg/kg on kaolin-carrageenan-induced edema was similar to that of aspirin, while 100 mg/kg showed the least activity. The data obtained from this study showed that the methanol extract of&nbsp;C. vogelii&nbsp;exhibited mild analgesic activity as well as anti-inflammatory activity. &nbsp; Key words:&nbsp;Analgesic, anti-inflammatory, mice,&nbsp;Cyphostemma vogelii,&nbsp;nociception.

Beneficial effects of Anadenanthera colubrina (Vell.) Brenan extract on the inflammatory and nociceptive responses in rodent models

Ethnopharmacological relevanceAnadenanthera colubrina (Vell.) Brenan, popularly known as “angico”, is a plant that has been widely used in folk medicine due to its anti-inflammatory property. To evaluate the pharmacological activities of this plant, studies were performed on its antinociceptive and anti-inflammatory properties. Materials and methodsThe AE of Anadenanthera colubrina, made from the bark, was used in rodents via oral route (p.o.), at 100, 200, and 400mg/kg in classical models of nociception (acetic acid-induced writhing and hot-plate test) and inflammation evoked by carrageenan (e.g., paw edema, peritonitis, and synovitis). ResultsThe acetic acid-induced abdominal writhes in mice were significantly reduced (P<0.001) by oral treatment with the extract (100, 200, and 400mg/kg), but the extract did not significantly increase the latency in the nociceptive hot-plate test. Anadenanthera colubrina aqueous extract reduced significantly the edema and, besides, diminished the mieloperoxidase activity (200 and 400mg/kg, P<0.01). The carrageenan-induced peritonitis was significantly reduced (P<0.05) by the aqueous extract at 100, 200, and 400mg/kg. The aqueous extract (200mg/kg) reduces the synovial leukocyte infiltration on carrageenan-induced synovitis in rats (P<0.01), but failed to significantly affect joint swelling and impaired mobility. ConclusionsWe show for the first time that the anti-inflammatory and peripheral antinociceptive activities of Anadenanthera colubrina are consistent, at least in part, with the use of this plant in popular medicine practices.

The antinociceptive properties of the novel compound (±)-trans-4-hydroxy-6-propyl-1-oxocyclohexan-2-one in acute pain in mice

The compound (±)-trans-4-hydroxy-6-propyl-1-oxocyclohexan-2-one [(±)-δ-lactone] was isolated from the plant Vitex cymosa Bertero, and determined to be the active principle. The present study aimed to evaluate the antinociceptive effect of (±)-δ-lactone and to elucidate its mechanism of action. Mice were subjected to in-vivo models of acute pain (acetic acid-induced abdominal writhing, formalin and hot-plate tests) and the open-field test. (±)-δ-Lactone, administered orally (6-900 µmol/kg), exerted a dose-dependent antinociceptive effect in the acetic acid-induced abdominal writhing, formalin and hot-plate tests. (±)-δ-Lactone administered by the intrathecal (i.t.) and subplantar (s.p.) routes (10-600 nmol) exerted concentration-dependent antinociceptive effects in the formalin test, showing its spinal and peripheral activity, respectively. In the hot-plate test, (±)-δ-lactone was also active when administered i.t., confirming its spinal effect. The previous intraperitoneal (i.p.) application of naloxone, yohimbine, mecamylamine or glibenclamide did not alter the effect produced by the i.t. administration of (±)-δ-lactone, whereas the previous application of atropine and L-arginine significantly reduced its effects in the formalin and hot-plate tests. The previous i.p. application of L-NAME enhanced the antinociceptive effect of the i.t. administration of (±)-δ-lactone in the formalin and hot-plate tests. The previous i.p. application of L-NAME and L-arginine increased and decreased, respectively, the activity of (±)-δ-lactone administered by s.p. administration. These results indicate that (±)-δ-lactone has significant spinal and peripheral antinociceptive activity, and that its effects are at least partially mediated by a reduced nitric oxide production/release, most likely through mechanisms involving the cholinergic system.

Antinociceptive Activity and Redox Profile of the Monoterpenes (+)-Camphene,p-Cymene, and Geranyl Acetate in Experimental Models

Objective. To evaluate antinocicpetive and redox properties of the monoterpenes (+)-camphene, p-cymene, and geranyl acetate in in vivo and in vitro experimental models. Methods. Evaluation of the in vitro antioxidant activity of (+)-camphene, p-cymene, and geranyl acetate using different free radical-generating systems and evaluation of antinociceptive actions by acetic acid-induced writhing and formalin-induced nociception tests in mice. Results. p-Cymene has the strongest antinociceptive effect, but (+)-camphene and geranyl acetate also present significant activity at high doses (200 mg/kg). (+)-Camphene had the strongest antioxidant effect in vitro at TBARS and TRAP/TAR assays and also had the highest scavenging activities against different free radicals, such as hydroxyl and superoxide radicals. Sodium nitroprussiate-derived NO production was enhanced by (+)-camphene. Geranyl acetate and p-cymene also presented some antioxidant effects, but with a varying profile according the free radical-generating system studied. Conclusion. (+)-Camphene, p-cymene, and geranyl acetate may present pharmacological properties related to inflammation and pain-related processes, being potentially useful for development of new therapeutic strategies, with limited possibilities for p-cymene and geranyl acetate.

Anti-inflammatory and antinociceptive activities of LQFM002 — A 4-nerolidylcatechol derivative

AimsThe current study describes the synthesis and pharmacological evaluation of (E)-N-(3,7-dimethylocta-2,6-dienyl)-1,3-dimethyl-1H-pyrazol-5-amine (LQFM002), a compound originally designed through a molecular simplification strategy from 4-nerolidylcatechol. LQFM002 was evaluated for preservation of the PLA2 enzyme inhibitory effects of the lead compound, 4-nerolidylcatechol, using in vitro and in vivo models. Main methodsRota-rod, open field and pentobarbital-induced sleeping tests were used to evaluate the effects of LQFM002 on the central nervous system. A gel plate assay of PLA2 activity, carrageenan-induced pleurisy and TNF-α levels was used to assay anti-inflammatory activity. Antinociceptive activities of LQFM002 were evaluated with acetic acid-induced writhing, formalin and hot-plate tests, while involvement of the opioid pathway in the LQFM002 antinociceptive effect was investigated with naloxone pre-treatment. Key findingsLQFM002 inhibited PLA2 activity, cell migration into the pleural cavity, and capillary permeability (Evan's blue concentration) and reduced TNF-α levels in pleural exudates. LQFM002 also reduced acetic acid-induced writhing and the licking time in both phases of the formalin test and increased latency in the hot-plate test. Pre-treatment with 8.25μmol/kg naloxone (3mg/kg) reversed the analgesic effects of LQFM002 in the early phase of the formalin test. SignificanceLQFM002 showed anti-inflammatory activity, which possibly involved reduction of leukocyte migration and TNF-α levels. LQFM002 also demonstrated inhibition of PLA2 activity in vitro. LQFM002 had an antinociceptive effect that involved the opioidergic system.

Analgesic, Anti-Inflammatory and Anticancer Activities of Extra Virgin Olive Oil

Background. In folk medicine, extra virgin olive oil (EVOO) is used as a remedy for a variety of diseases. This study investigates the in vivo antinociceptive, anti-inflammatory, and anti-cancer effects of EVOO on mice and rats. Materials and Methods. In this experimental study, using the acetic acid-induced writhing and formalin tests in mice, the analgesic effect of EVOO was evaluated. Acetylsalicylic acid and morphine were used as standard drugs, respectively. The anti-inflammatory activity was investigated by means of the carrageenan-induced paw edema model in rats using acetylsalicylic acid and dexamethasone as standard drugs. Last, the xenograft model in athymic mice was used to evaluate the anticancer effect in vivo. Results. EVOO significantly decreased acetic acid-induced abdominal writhes and reduces acute and inflammatory pain in the two phases of the formalin test. It has also a better effect than Dexamethasone in the anti-inflammatory test. Finally, the intraperitoneal administration of EVOO affects the growth of HCT 116 tumours xenografted in athymic mice. Conclusion. EVOO has a significant analgesic, anti-inflammatory, and anticancer properties. However, further detailed studies are required to determine the active component responsible for these effects and mechanism pathway.

Synthesis and analgesic activity of new heterocyclic compounds derived from monoterpenoids

A set of new heterocyclic compounds with different types of framework, including a new type of framework, were synthesized by reactions of verbenol epoxide and (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol with aromatic aldehydes containing three methoxy groups. The analgesic activity of these substances was studied. Three compounds possessed considerable activity in vivo in the acetic acid-induced writhing test. (2S,4R,4aR,8S,8aR)-4,7-Dimethyl-2-(2,4,5-trimethoxyphenyl)-3,4,4a,5,8,8a-hexahydro-2H-4,8-epoxychromene exhibited high analgesic activity in both acetic acid-induced writhing and hot plate tests; its selectivity index IS50 exceeded 60.

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.

English

This study was carried out to evaluate the antinociceptive effects of ethanolic extract fromNeoglaziovia variegata&nbsp;(Nv-EtOH) in mice using models of nociception. The evaluation of antinociceptive activity was carried out by the acetic acid-induced writhing, formalin and hot plate tests. HPLC was used to determine the fingerprint chromatogram of the Nv-EtOH. In the acetic acid-induced writhing test, the Nv-EtOH (100, 200 and 400 mg/kg, i.p.) reduced the number of writhing by 89.50, 71.34 and 87.42%, respectively. Additionally, the extract decreased by 46.67, 44.23 and 41.81%, respectively, the paw licking time in the first phase of the formalin test, as well as 70.14, 69.43 and 90.28%, respectively, in the second phase of this test. In the hot plate test, Nv-EtOH increased the reaction time when compared to control group. The effects of Nv-EtOH and morphine in the formalin and hot plate tests were antagonized by naloxone. The presence of phenolic compounds in the extract was confirmed using HPLC. Results based from formalin and hot plate tests indicated that the extract has compounds that interact with the opioid system. The effect of Nv-EtOH on hot plate response provides a confirmation of its central effect. Pharmacological and chemical studies are continuing in order to characterize the mechanism responsible for this effect. &nbsp; Key words:&nbsp;Antinociceptive activity, phenolic compounds,&nbsp;Neoglaziovia variegata, Bromeliaceae.