Antinociceptive effectiveness of triterpenes from rosemary in visceral nociception

Ethnopharmacological relevance

Rosemary is a species used worldwide as a common spice, but also in folk medicine for their therapeutic properties against abdominal pain. The rationale of this study was to examine the involvement of triterpenes and to compare their effectiveness in the antinociceptive effect of an ethanol extract of Rosmarinus officinalis L. (Lamiaceae).

Material and methods

Fractionation and HPLC analyses allowed the identification of a mixture of micromeric (121 mg/g), oleanolic (64 mg/g) and ursolic (83 mg/g) acids as partial antinociceptive responsible in an ethyl acetate fraction of R. officinalis by using the acetic acid-induced abdominal constrictions model in mice.

Results

These triterpenes individually evaluated produced a significant and dose-dependent antinociceptive response with similar potency as follows: ED₅₀=1.1 mg/kg (0.9–1.3 mg/kg), 2.1 mg/kg (1.6–2.6 mg/kg) and 1.6 mg/kg (1.1–2.1 mg/kg), respectively, by using the intraperitoneal (i.p.) route of administration in mice. Their maximal antinociceptive efficacy resembled that produced by ketorolac (10 mg/kg, i.p.), a common clinic analgesic.

Conclusion

Our results provide evidence that these triterpenes participate in the antinociceptive activity of R. officinalis. In addition, each individual triterpene showed a similar potency to that observed with ketorolac, a non-steroidal anti-inflammatory drug, in this experimental model.     

Antinociceptive activity of Mirabilis jalapa in mice

Ethnopharmacological relevance

The infusion or decoction of Mirabilis jalapa leaves is used in traditional medicine in Brazil to treat inflammatory and painful diseases.

Aim of the study

The present study examined the antinociceptive effect of Mirabilis jalapa extracts from leaves and stems in models of pain in mice.

Materials, methods and results

The crude hydroethanolic extract from leaves (CrdL) was more potent than the crude extract from stems (CrdS) to inhibit abdominal constrictions induced by acetic acid, with ID₅₀ values of 5.5 (2.3–13.1) and 18.0 (11.3–28.5) mg/kg, respectively. Among the fractions tested, the Eta fraction from leaves (Eta) was more effective (maximal inhibition of 83 ± 8%) and potent (ID₅₀ of 1.1 (0.6–2.1) mg/kg) to induce antinociception. Eta and CrdL also possessed an antinociceptive effect in the tail-flick test. Pre-treatment with naloxone did not modify the antinociceptive effect of Eta, but co-administration with atropine completely prevented it. This suggests that the antinociceptive effect might depend on the cholinergic system. Instead, Eta was not able to alter the acetylcholinesterase activity in blood or spinal cord. Concerning side effects, Eta did not alter locomotor activity, body temperature, gastrointestinal transit and did not produce gastric lesions.

Conclusion

Our results demonstrate that Mirabilis jalapa presents antinociceptive activity in mice, which supports its folkloric use as an analgesic.     

Anti-nociceptive and anti-inflammatory activities of the Agastache mexicana extracts by using several experimental models in rodents

Ethnopharmacological relevance

Agastache mexicana is a plant that has long been used in large demand in Mexican folk medicine to treat pain, among others affections. Nevertheless, no scientific data confirming its use have been reported. The aim of this investigation was to examine the spectrum of antinociceptive activity of A. mexicana by using different experimental models of nociception in rodents.

Material and methods

Nociceptive activity was induced 30 min post treatment of different doses of hexane, ethyl acetate and methanol extracts from A. mexicana aerial parts. The writhing test in mice, and the formalin and plantar tests as well as the pain-induced functional impairment assay in rats (PIFIR model) were the experimental nociceptive models used. Antinociceptive response of the organic extracts was compared to that observed with the analgesic drug tramadol.

Results

A. mexicana organic extracts produced a dose-dependent and significant inhibition of the abdominal constrictions caused by 1% acetic acid injection (i.p.) in mice. A maximal antinociceptive effectiveness obtained with tramadol was also observed with the administration of hexane and ethyl acetate extracts in comparison to less effectiveness obtained with the methanol extract. At the same range of doses, A. mexicana organic extracts inhibited the behavioral responses in both phases of the formalin pain test, in which a more intense effect was observed in the inflammatory phase than in the neurogenic stage. With regard to the plantar test and PIFIR model, a significant but not dose-dependent antinociceptive response was observed at specific doses that depended on the organic extract evaluated.

Conclusion

The antinociceptive activity of A. mexicana aerial parts depends on the intensity of the painful stimulus induced and involves different kinds of constituents. Our present results reinforce the use of this species in traditional medicine and its utility for pain treatment mainly associated with inflammation.     

Acute toxicity, antinociceptive activity and indole alkaloids of aqueous extract from bark of Aspidosperma cuspa (Kunth) Blake

Etnopharmacological relevance

Aspidosperma cuspa (Kunth) Blake (Apocynaceae) is popularly known as “amargosa” or “cuspa”, and its bark is used in folk medicine primarily for pain.

Aim of the study

In the present study the acute toxicity, antinociceptive effect and alkaloids of the aqueous decoction extract of the Aspidosperma cuspa bark in mice was investigated.

Materials and methods

Acute toxicity was tested using a variation of the method described by Lichfield and Wilcoxon. The antinociceptive activity was evaluated using the acetic acid induced writhing and tail-flick tests. The phytochemical analysis was performed.

Results and conclusion

Oral administration of the extract did not cause animal death (LD₅₀>4 g/kg), and the histological analysis showed an absence of alterations in all organs examined. TD₅₀ of the extract was 0.5521 g/kg for male mice and 1.1565 g/kg for females. The aqueous extract at doses 276 mg/kg (p.o.) did not produce a significant inhibition of acetic acid-induced writhes, but showed a significant effect in tail-flick test. Naloxone, an opioid receptor antagonist, pretreatment inhibited significantly the antinociceptive activity of the extract. It is suggested that the aqueous decoction extract of the bark of Aspidosperma cuspa has an antinociceptive effect, and this may be mediated by opioid receptors. Three indole alkaloids (aspidocarpine, 11-methoxytubotaiwine and picraline) were isolated from the aqueous extract. The antinociceptive activity of the extract is presumed to be due to these compounds.     

Antinociceptive activity of fruits extracts and “arrope” of Geoffroea decorticans (chañar)

Ethnopharmacological relevance

Geoffroea decorticans (chañar) fruits and their derivate product (arrope) have been traditionally used as food and a folk medicine for the treatment of a wide variety of diseases including bronchopulmonary disorders and to relieve dolorous process.

Aim of the study

In order to evaluate the pharmacology action of this plant, studies were performed of antinociceptive and antioxidant activities.

Materials and methods

The aqueous and ethanolic extracts and arrope of chañar were evaluated in various established pain models, including chemical nociception induced by subplantar formalin and intraperitoneal acetic acid and thermal nociception method, such as tail immersion test in rats. To examine the possible connection of the opioid receptor to the antinociceptive activity of extracts and arrope it was performed a combination test with naloxone, a non-selective opioid receptor antagonist.

Results

The aqueous extract and arrope (1000 mg/kg) caused an inhibition of the pain in formalin test in the first phase, similar to morphine and decrease in the second phase. In a combination test using naloxone, diminished analgesic activity of aqueous extract and arrope were observed, indicating that antinociceptive activity is connected with the opioid receptor. The aqueous extract and arrope, caused an inhibition of the writhing response induced by acetic acid. Central involvement in analgesic profile was confirmed by the tail immersion test, in which the aqueous extract and arrope showed a significant analgesic activity by increasing latency time. The aqueous extract showed higher antioxidant activity than the arrope, it may be due to the cooking process.

Conclusions

This study has shown that the aqueous extract and arrope of Geoffroea decorticans (chañar) fruits, does possess significant antinociceptive effects. It is further concluded that aqueous extract with maximum inhibition of free radical is the most potent extract amount tested extracts. At the oral doses tested the aqueous extract and arrope were non-toxic. The present results justifies their popular use and constitutes the first validation study of the antinociceptive action.     

Analgesic and anti-inflammatory activities of ethanol root extract of Mahonia oiwakensis in mice

Aims of the study

This study investigated the anti-inflammatory and analgesic activities, and protoberberine alkaloid contents of ethanol extract of MO roots (MOR_EtOH).

Materials and methods

The analgesic activity of MOR_EtOH was determined using acetic acid-induced writhing response and formalin test. The anti-inflammatory activity of MOR_EtOH was determined using the λ-carrageenan-induced paw oedema model. The protoberberine alkaloid contents of MOR_EtOH were identified by high-performance liquid chromatography (HPLC).

Results

MOR_EtOH (100 and 500 mg/kg) decreased the acetic acid-induced writhing responses and licking times of the second phase in the formalin test. Moreover, carrageenan-induced paw oedema was significantly reduced in a dose-dependent manner by administering MOR_EtOH (100 and 500 mg/kg) at 3, 4, and 5 h after the carrageenan injection. The serum levels of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) of MOR_EtOH-treated mice were significantly reduced compared with those in the serum of animals administered carrageenan. Notably, MOR_EtOH attenuated the expression of cyclo-oxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) and neutrophil infiltration in paw tissues injected with carrageenan. The anti-inflammatory mechanisms of MOR_EtOH appear to be related to the inhibition of neutrophil infiltration, iNOS and COX-2 protein expression, NO release, and the decreasing TNF-α level in serum. The analytical results showed that the contents of berberine, palmatine and jatrorrhizine were 191.45 mg/g extract, 100.15 mg/g extract and 66.45 mg/g extract, respectively.

Conclusion

These experimental results suggest that MOR_EtOH produced both analgesic and anti-inflammatory effects in mice and may be a candidate for the development of pharmacological agents used in the treatment of inflammatory disorders.     

Antinociceptive and anti-inflammatory activity of Sambucus palmensis link,an endemic Canary Island species

Ethnopharmacological relevance

Sambucus palmensis Link is an endemic species of the Canary Islands, popularly known as “Saúco canario”. This species has wide use in folk medicine practice on the islands, especially as analgesic and anti-inflammatory. So the aim of our study is to evaluate the antinociceptive and anti-inflammatory activity of an aqueous extract of this species.

Materials and methods

Three aqueous extract doses (35, 52.5 and 70 mg/kg) were orally administered to laboratory Swiss mice obtained from the Central Animal House of La Laguna University. Writhing responses induced by phenylquinone, formalin induced paw pain response, tail-flick test and paw edema induced by carrageenan were evaluated in this work.

Results

Oral pretreatment with 52.5 and 70 mg/kg Sambucus palmensis aqueous extract significantly reduced the writhing number induced by phenylquinone injection (61.64 and 89.04% respectively), and the pain response in the first (36.67 and 38.89%) and second (57.28 and 70.1%) phases respectively of the formalin test. Sambucus palmensis had a very slight effect on tail-flick test and inhibited moderately the edema formation induced by carrageenan in mice.

Conclusions

These data show for the first time that Sambucus palmensis has a significant antinociceptive effect that seems to be more peripherical than central. Sambucus palmensis also displays a moderate anti-inflammatory activity in an acute inflammation model. These results support the widespread use of Sambucus palmensis in popular medicine to treat pain and inflammation.     

Involvement of the L-arginine-nitric oxide pathway in the antinociception caused by fruits of Prosopis strombulifera (Lam.) Benth

Ethnopharmacological relevance

Prosopis strombulifera (Lam.) Benth. is a rhizomatous shrub that grows in the north and central zone of Argentina. In folk medicine, the fruits of this plant have been used as an astringent, anti-inflammatory and odontalgic agent and anti-diarrheic.

Aim of the study

To investigate the antinociceptive effect of ethanol (EE), chloroform (CE) and ethyl acetate (EtOAcE) extracts of Prosopis strombulifera fruits and the involvement of the l-arginine-nitric oxide pathway in this effect.

Materials and methods

The antinociceptive effects of the EE, CE and EtOAcE of Prosopis strombulifera fruits were evaluated in vivo using the formalin-induced pain test in mice with aspirin and morphine as reference antinociceptive compounds. The participation of the l-arginine-nitric oxide pathway in the antinociceptive effect was investigated in the same animal model using l-arginine as a nitric oxide (NO) precursor. The in vitro inhibitory effect of the extracts on LPS-induced nitric oxide production and iNOS expression was investigated in a J774A.1 macrophage-derived cell line.

Results

CE (300 mg/kg), in contrast to EE and EtOAcE, caused significant inhibition (p < 0.05) of the in vivo nociceptive response. Moreover, CE (100–1000 mg/kg, p.o.) produced a dose-dependent inhibition of the neurogenic and the inflammatory phases of the formalin test with inhibition values (at 600 mg/kg) of 42 ± 7% and 62 ± 7%, respectively. CE inhibition was more potent in the inflammatory phase, with an ID₅₀ of 400.1 (252.2–634.8) mg/kg. The antinociception caused by CE (600 mg/kg, p.o.) was significantly attenuated (p < 0.05) by i.p. treatment of mice with l-arginine (600 mg/kg). In addition, CE (100 μg/mL) produced significant in vitro inhibition (p < 0.001) of LPS-induced NO production, which was not observed with EE and EtOAcE at the same concentration. The inhibition of NO production by CE (10–100 μg/mL) was dose-dependent, with an IC₅₀ of 39.8 (34.4–46.1) μg/mL, and CE significantly inhibited LPS-induced iNOS expression in J774A.1 cells.

Conclusions

This study supports, in part, the ethnomedical use of Prosopis strombulifera fruits by showing that its CE produces moderate antinociception in vivo. The findings also provide scientific information for understanding the molecular mechanism involved in the analgesic effect of this plant.     

Anti-inflammatory and anti-nociceptive activities of Platanus orientalis Linn. and its ulcerogenic risk evaluation

Ethnopharmacological relevance

Leaves of Platanus orientalis Linn. are used in folk medicine as a wound-healer and ophthalmologic agent. Phytol derivatives from the leaves of plane-tree show anti-ulcer activity. Its analgesic and anti-inflammatory effects for knee pain were known to Persian scientists and hakims.

Materials and methods

The ethanolic extract of Platanus orientalis Linn. and its various fractions were given at a dose of 100 mg/kg po and 200 mg/kg po for testing their anti-inflammatory activity by carrageenan induced hind paw edema. The analgesic activity of the ethanolic extract and its fractions has been carried out by tail-flick method and writhing test at a dosage of 200 mg/kg po. Gastric ulceration studies have been further carried out to study the ulcerogenic risk evaluation of the ethanolic extract and its various fractions at a dose of 600 mg/kg body weight.

Results

Among the tested fractions, chloroform fraction exhibited better inhibition (68.33%) at 200 mg/kg po dosage when compared to the standard drug Ibuprofen (66.66%) after 3 h in the carrageenan induced hind paw edema. The ethanolic extract and all its fractions especially the chloroform (p<0.01) showed significant analgesic activity with insignificant ulceration as compared to the standard drug i.e. Ibuprofen. The histopathological study of ethanolic extract and its fractions revealed that none of them cause ulcer.

Conclusion

The present study indicates that Platanus orientalis Linn. has significant anti-inflammatory and analgesic effect.     

Anti-nociceptive and anti-inflammatory activity of sophocarpine

Aim of the study

This study aimed to assess the anti-nociceptive and anti-inflammatory activity of sophocarpine in rodents.

Materials and methods

The anti-nociceptive effect was evaluated in two experimental animal models and anti-inflammatory effect in three animal models, and sophocarpine was given by tail vein injection for the above study.

Results

Pretreatment with a single dose of sophocarpine (20 and 40 mg/kg) produced dose-dependent anti-nociceptive effects in thermally and chemically induced mouse pain models. Pretreatment with a single dose of sophocarpine also produced significant dose-dependent anti-inflammatory effects on carrageenan-induced rat hind paw edema (15 and 30 mg/kg), xylene-induced mouse ear edema (20 and 40 mg/kg) and acetic acid-induced mouse vascular permeation (20 and 40 mg/kg).

Conclusions

Sophocarpine possesses peripheral and central analgesic properties as well as anti-inflammatory activity on acute inflammatory processes.     

Antinociceptive activity of aqueous extract and isolated compounds of Lithrea molleoides

Ethnopharmacological relevance

Lithrea molleoides (Vell.) Engl. (Anacardiaceae) is a medicinal plant commonly used in traditional medicine in South America.

Aim of the study

In the present study, the in vivo antinociceptive effect of L. molleoides' aqueous extract and its isolated compounds has been investigated.

Materials and Methods

Antinociceptive activity was evaluated through writhing, formalin and hot plate tests in mice. The phytochemical analysis was performed.

Results

The extract produced significant inhibition on nociception induced by acetic acid (ED50: 8.7 mg/kg, i.p.) and formalin (ED50: 7.7 mg/kg, i.p.) administered intraperitoneally and also orally. Yohimbine diminished the activity of the extract in the acetic acid test meanwhile haloperidol enhanced its effect. Two majority compounds, shikimic and vanillic acid were active in chemical nociceptive models used in this work, producing the highest inhibition of the writhing response at a dose of 30 mg/kg i.p. (55.4% and 57.1%, respectively) meanwhile at 100 mg/kg p.o. produced a slight response (23.3% and 23.9%, respectively).

Conclusions

These results suggest that L. molleoides' aqueous extract produced antinociception possibly related to the presence of shikimic and vanillic acid. The adrenergic and dopaminergic systems seem to be involved in the mechanism of antinociception of the extract.     

Analgesic and anti-inflammatory effects of the dry matter of culture broth of Termitomyces albuminosus and its extracts

Aim of the study

The objectives of this study were to investigate the analgesic and anti-inflammatory effects of the dry matter of culture broth (DMCB) of Termitomyces albuminosus in submerged culture and its crude saponin extract (CSE) and crude polysaccharide extract (CPE).

Materials and methods

The analgesic effects of DMCB, CSE and CPE were evaluated with models of acetic acid-induced writhing response and formalin test in mouse. The anti-inflammatory effects of DMCB, CSE and CPE were evaluated by using models of xylene-induced mouse ear swelling and carrageen-induced mouse paw edema.

Results

The DMCB, CSE and CPE significantly decreased the acetic acid-induced writhing response and the licking time on the late phase in the formalin test. Treatment of DMCB (1000 mg/kg), CSE (200 mg/kg) or CPE (200 mg/kg) inhibited the mouse ear swelling by 61.8%, 79.0% and 81.6%, respectively. In the carrageen-induced mouse paw edema test, the group treated with indomethacin showed the strongest inhibition of edema formation by 77.8% in the third hour after carrageenan administration, while DMCB (1000 mg/kg), CSE (200 mg/kg) and CPE (200 mg/kg) showed 48.4%, 55.6% and 40.5%, respectively.

Conclusions

The results suggested that DMCB of Termitomyces albuminosus possessed the analgesic and anti-inflammatory activities. Saponins and polysaccharides were proposed to be the major active constituents of Termitomyces albuminosus in submerged culture.     

Evaluation of the antinociceptive, anti-inflammatory and gastric antiulcer activities of the essential oil from Piper aleyreanum C.DC in rodents

Ethnopharmacological relevance

Piper aleyreanum is a small tree that is widely distributed in tropical and subtropical regions, mostly in North and South America, and is used as an immunomodulator, analgesic and antidepressant in folk medicine.

Aim of the study

This study was designed to investigate the antinociceptive, anti-inflammatory and gastric antiulcer activities of the essential oils from the aerial parts of Piper aleyreanum (EOPa) in rodents.

Materials and methods

The antinociceptive and anti-inflammatory effects of orally administered EOPa were evaluated in mice subjected to the formalin and pleurisy models, respectively. We also pretreated the rats with EOPa before acute ethanol-induced gastric lesions and measured gastric lesion extension and mucus and glutathione (GSH) levels in the gastric mucosa. Finally, we performed a phytochemical analysis of EOPa.

Results

The chemical composition of EOPa was analyzed by gas chromatography and mass spectrometry (GC/MS), which identified 35 compounds, representing 81.7% of total oil compounds. Caryophyllene oxide (11.5%), β-pinene (9%), spathulenol (6.7%), camphene (5.2%), β-elemene (4.7%), myrtenal (4.2%), verbenone (3.3%) and pinocarvone (3.1%) were the major oil constituents. The oral administration of EOPa (10–1000 mg/kg) significantly inhibited the neurogenic and inflammatory phases of formalin-induced licking, with ID50 values of 281.2 and 70.5 mg/kg, respectively. The antinociception caused by EOPa (100 mg/kg, p.o.) was not reversed by naloxone (1 or 5 mg/kg, i.p.) in the formalin test. EOPa (100–300 mg/kg, p.o.) did not affect animal motor coordination in an open-field model. In carrageenan-induced pleurisy, EOPa (1–100 mg/kg, p.o.) significantly decreased the total cell count, neutrophils and mononuclear cells with mean ID50 values of 53.6, 21.7 and 43.5 mg/kg, respectively. In addition, EOPa (1–30 mg/kg, p.o.) protected the rats against ethanol-induced gastric lesions with an ID50 value of 1.7 mg/kg and increased the mucus and GSH levels of the gastric mucosa to levels similar to those of the non-lesioned group.

Conclusions

These data show for the first time that EOPa has significant antinociceptive and anti-inflammatory actions, which do not appear to be related to the opioid system. EOPa also has interesting gastroprotective effects related to the maintenance of protective factors, such as mucus production and GSH. These results support the widespread use of Piper aleyreanum in popular medicine and demonstrate that this plant has therapeutic potential for the development of phytomedicines with antinociceptive, anti-inflammatory and gastroprotective properties.     

Bioactivity guided isolation of analgesic and anti-inflammatory constituents of Cnestis ferruginea Vahl ex DC (Connaraceae) root

Ethnopharmacological relevance

Cnestis ferruginea (CF) Vahl ex DC (Connaraceae) is a shrub widely used in Traditional African Medicine (TAM) for the treatment of various painful and inflammatory conditions.

Aim of the study

To isolate the active pharmacological constituents responsible for the anti-inflammatory and antinociceptive properties of the methanolic root extract of C. ferruginea.

Materials and methods

The crude methanolic root extract of CF was sequentially fractionated into four sub extracts (chloroform, ethylacetate, n-butanol and the remaining aqueous fraction). The aqueous–butanol fractions, having showed significant inhibition of inflammation and pain, were subjected to fractionation through successive column chromatography on silica gel 60–120 mesh, eluted with a gradient of CHCl₃–MeOH.Sixty five fractions were collected; fractions with similar TLC profiles were grouped into seven major fractions (1–7). Fraction 4 being the most active in bioassay was rechromatographed to obtain CF-2. Analgesic activity was evaluated using the acetic acid-induced writhing and hot plate tests in mice while carrageenan induced paw oedema test was used to investigate the anti-inflammatory actions of the fractions obtained.

Result

Amentoflavone (CF-2) was isolated from the aqueous/n-butanol fraction. CF-2 (12.5, 25 and 100 mg/kg; p.o) produced significant (P<0.05) dose dependent inhibition of pain response elicited by acetic acid and increased nociceptive reaction latency in hot plate test. In addition it produced significant (P<0.05) dose-dependent inhibition of oedema in the carrageenan-induced inflammation.

Conclusion

This study showed that amentoflavone is responsible for the analgesic and anti-inflammatory activity of Cnestis ferruginea.     

Evaluation of the antinociceptive activity of extracts of Sonchus oleraceus L. in mice

Ethnopharmacological relevance

Sonchus oleraceus L. has been used to relieve pain in Brazilian folk medicine.

Aim of the study

Sonchus oleraceus L. has been used to relieve pain in Brazilian folk medicine. This study was conducted to establish the antinociceptive properties of hydroethanolic and dichloromethane extracts from aerial parts of Sonchus oleraceus in mice using chemical and thermal models of nociception.

Materials and methods

The formalin, hot plate, and tail immersion tests as well as acetic acid-induced writhing were used to investigate the antinociceptive activity in mice.

Results

Given orally, the extracts at test doses of 30–300 mg/kg, produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid and subplantar formalin since decreased the number of writhing episodes and the time licking. Treatment with the extracts in the same doses produced a significant increase of the reaction time in tail immersion and in the hot plate test. The extracts administered at 300 mg/kg, p.o. had a stronger antinociceptive effect than indomethacin (5 mg/kg, p.o.) and morphine (10 mg/kg, p.o.).

Conclusion

The extracts of Sonchus oleraceus markedly demonstrated antinociceptive action in mice, which supports previous claims of its traditional use.     

Geopropolis from Melipona scutellaris decreases the mechanical inflammatory hypernociception by inhibiting the production of IL-1β and TNF-α

Ethnopharmacological relevance

The pharmacological activity of geopropolis collected by stingless bees (important and threatened pollinators), a product widely used in folk medicine by several communities in Brazil, especially in the Northeast Region, needs to be studied.

Objective

The aim of this study was to evaluate the antinociceptive activity of Melipona scutellaris geopropolis (stingless bee) using different models of nociception.

Material and methods

The antinociceptive activity of the ethanolic extract of geopropolis (EEGP) and fractions was evaluated using writhing induced by acetic acid, formalin test, carrageenan-induced hypernociception, and quantification of IL-1β and TNF-α. The chemical composition was assessed by quantification of total flavonoids and phenolic compounds.

Results

EEGP and its hexane and aqueous fractions showed antinociceptive activity. Both EEGP and its aqueous fraction presented activity in the mechanical inflammatory hypernociception induced by the carrageenan model, an effect mediated by the inhibition of IL-1β and TNF-α. The chemical composition of EEGP and its hexane and aqueous fractions showed a significant presence of phenolic compounds and absence of flavonoids.

Conclusion

Our data indicate that geopropolis is a natural source of bioactive substances with promising antinociceptive activity.     

Analgesic and anti-inflammatory effects of Ligularia fischeri leaves in experimental animals

Aim of the study

The ethanol extract (LF) of Ligularia fischeri var. spiciformis (leaf) has been evaluated for antinociceptive and anti-inflammatory activities in mice.

Materials and Methods

Analgesic and anti-inflammatory activities were studied by measuring nociception induced by formalin, acetic acid and hot-plate, and inflammation induced by carrageenan, formalin, and arachidonic acid.

Results

The acute treatment of mice with LF at doses of 100 and 200 mg/kg, by oral administration, produced a significant antinociceptive effect in the acetic acid-induced writhing, formalin-induced pain licking and hot-plate-induced pain. Also, the LF significantly inhibited both carrageenan- and formalin-induced inflammation as well as arachidonic acid-induced ear edema in mice.

Conclusions

These inhibitions were statistically significant (P < 0.05). Thus, our investigation suggests a potential benefit of Ligularia fischeri in treating conditions associated with inflammatory pain.     

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

Aim of the study

Antinociceptive 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 methods

RA was evaluated on anti-nociceptive activity in mice using chemical and thermal models of nociception.

Results

RA administered intraperitoneally at doses of 10, 20, 40 and 80 mg/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.

Conclusions

Therefore, it is reasonable that the analgesic mechanism of RA possibly involved the NO-cGMP signaling pathway and L-type Ca²⁺ channels.     

Antinociceptive activity of methanol extract of flowers of Impatiens balsamina

Ethnopharmacological relevance

Impatiens balsamina Linn. (Balsaminaceae), an annual herb locally called “Dopati”, is cultivated as an ornamental garden plant in Bangladesh. Flowers of the plant are used in folk medicine to treat lumbago, neuralgia, burns and scalds.

Aim of the study

This study evaluated the antinociceptive effect of the methanol extract of I. balsamina flowers (MIB).

Materials and methods

The extract was evaluated for antinociceptive activity using chemical- and heat-induced pain models such as acetic acid-induced writhing, hot plate, tail immersion and formalin test. To verify the possible involvement of opioid receptor in the central antinociceptive effect of MIB, naloxone was used to antagonize the effect. The effect of MIB on central nervous system (CNS) was also studied using hole cross and open field tests.

Results

MIB demonstrated strong and dose-dependent antinociceptive activity in all the chemical- and heat-induced mice models (p<0.05). These findings imply the involvement of both peripheral and central antinociceptive mechanisms. The use of naloxone confirmed the association of opioid receptors in the central antinociceptive effect. MIB also showed significant central nervous system depressant effect (p<0.05).

Conclusion

This study reported the peripheral and central antinociceptive activity of the flowers of I. balsamina and rationalized the traditional use of the flower in the treatment of different painful conditions.