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 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.     

The antinociceptive activity of Polygonatumverticillatum rhizomes in pain models

Aim of the study

The current study was designed to establish the pharmacological rationale for the traditional use of the rhizomes of Polygonatum verticillatum in the treatment of painful conditions and as a plant diuretic.

Materials and methods

The crude methanolic extract of the rhizomes of Polygonatumverticillatum (PR) was tested in various established pain models in rodents at 50, 100 and 200 mg/kg i.p. while the diuretic activity was assessed at 300 and 600 mg/kg p.o. in rats.

Results

PR demonstrated significant reduction (14–72%) in the number of writhes induced by acetic acid in a dose-dependent manner. When nociceptive threshold was measured in the formalin test, PR strongly attenuated the formalin-induced flinching behaviour in both phases (6–30% in first phase while 12–72% in second phase). Central involvement in the analgesic profile of PR was confirmed by the hot plate test, in which PR elicited a significant (P < 0.01) analgesic activity by increasing latency time. However, an opioid receptor antagonist, naloxone (2 mg/kg s.c.) strongly antagonized the antinociceptive activity of PR. As a plant diuretic, PR showed mild but statistically insignificant diuretic activity at 300 mg/kg. The crude extract and solvent fractions of the plant contained reasonable quantity of total saponin and alkaloid contents.

Conclusions

The mechanisms underlying the analgesic action of PR shows that the opioid dependant central mediation has synergistic effect by enforcing the peripheral analgesic effects. Interestingly, our findings not only substantiated the folk use of the plant as an analgesic but also reported for the first time in the whole genus.     

Evaluation of antinociceptive effects of Crassocephalum bauchiense Hutch (Asteraceae) leaf extract in rodents

Ethnopharmacological relevance

The leaves of Crassocephalum bauchiense have long been used in traditional Cameroonian medicine for the treatment of epilepsy, pain, inflammatory disorders, arthritis and intestinal pain.

Aim of the study

In this study, we attempted to identify the possible antinociceptive action of the aqueous extract and the alkaloid fraction prepared from the leaves of Crassocephalum baucheiense.

Materials and methods

Using acetic acid induced abdominal constrictions, formalin-, capsaisin- and glutamate-induced nociception, and hot plate assay procedures, the antinociceptive effects of the aqueous extract and the alkaloid fraction was assessed after oral administration in mice. Morphine sulfate was used as reference analgesic agent. Mice were submitted to the rota-rod task and open-field test in order to assess any non-specific muscle-relaxant or sedative effects of the extracts of Crassocephalum bauchiense. Male and female Swiss mice were used to assess acute toxicity of these extracts.

Results

The aqueous extract and the alkaloid fraction of Crassocephalum bauchiense produced a significant antinociceptive effects in the acetic acid, formalin, glutamate, capsaicin and hot plate tests. These antinociceptive effects of Crassocephalum bauchiense were significantly attenuated by pretreatment with naloxone. The extracts of Crassocephalum bauchiense did not alter the locomotion of animals in the open-field or rotarod tests, which suggest a lack of a central depressant effect. The animals did not exhibit any acute toxicity to the aqueous extract and the alkaloid fraction, so it was not possible to calculate the LD₅₀.

Conclusion

The results confirm the popular use of Crassocephalum bauchiense as an antinociceptive, and contribute to the pharmacological knowledge of this species because it was shown that the aqueous extract and the alkaloid fraction of Crassocephalum bauchiense produced dose related antinociception in models of chemical and thermal nociception through mechanisms that involve an interaction with opioidergic pathway.     

Anti-inflammatory and antinociceptive activities of the ethanolic extract of Bougainvillea xbuttiana

Ethnopharmacological relevance

Bougainvillea xbuttiana is widely distributed in Mexico and it is used as an analgesic in folk medicine.

Aim of the study

In the present study the in vivo antinociceptive and anti-inflammatory effects of the Bougainvillea xbuttiana ethanolic extract have been studied in mice.

Materials and methods

The phytochemical analysis was performed. Antinociceptive activity was evaluated through writhing and formalin test in mice. The anti-inflammatory activity was determined with the carrageenan-induced mice paw oedema model. IL-6, IL-10 and IFN-γ levels were determined by enzyme-like immunosorbent assay, whereas TNF and nitrite levels were detected by standard assay with L929 cells and colorimetric Griess reactive, respectively.

Results

The results showed that the ethanolic extract of the Bougainvillea xbuttiana has significant anti-inflammatory and antinociceptive activities, by inhibition of nociception induced by acetic acid and paw oedema. This extract also induced a decrease in TNF levels and an increase of IL-6, IFN-γ and NO levels that we observed up to 2 h. The highest levels of IL-10 were observed up to 4 h. The ratios of pro-/anti-inflammatory cytokines in sera from mice injected with the ethanolic extract, may be manifesting an anti-inflammatory status.

Conclusions

The present study provides convincing evidences that Bougainvillea xbuttiana extract possesses significant anti-nociceptive and anti-inflammatory effects.     

Antinociceptive effect of ethanol extract of leaves of Lannea coromandelica

Ethnopharmacological relevance

Lannea coromandelica (Houtt.) Merr. is a plant locally called “Jiga”, found all over Bangladesh. Leaf of the plant is traditionally used in the treatment of local swellings, pains of body, toothache etc. This study evaluated the antinociceptive effect of the ethanol extract of L. coromandelica leaves (EELC).

Materials and methods

The antinociceptive activity of the extract (at the doses of 50, 100, and 200 mg/kg) was evaluated by using chemical- and heat-induced pain models such as acetic acid-induced writhing, hot plate, tail immersion, formalin, and glutamate test. To verify the possible involvement of opioid receptor in the central antinociceptive effect of EELC, naloxone was used to antagonize the effect. Besides, the involvements of ATP-sensitive K⁺ channel and cGMP pathway were also justified by using glibenclemide and methylene blue.

Results

EELC demonstrated significant dose-dependent antinociceptive activity in the chemical- and heat-induced nociception in 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. EELC also showed the involvements of ATP-sensitive K⁺ channel and cGMP pathway for antinociceptive activity.

Conclusions

This study reported the antinociceptive activity of the leaf of L. coromandelica and rationalized the traditional use of the leaf in the treatment of different painful conditions.     

Antinociceptive,anti-inflammatory and antioxidant activities of aqueous extract from Remirea maritima (Cyperaceae)

Ethnopharmacological relevance

Remirea maritima Aubl., popularly known as “capim-da-praia”, is popularly employed in the treatment of diarrhea, kidney disease, fever, and for analgesic and anti-inflammatory purposes through the preparation of teas. Few studies have focused on the chemical composition and its biological properties.

Aim of the study

This work evaluated the antinocipetive, anti-inflammatory and antioxidant activities of the aqueous extract from Remirea maritima Aubl. as well as the isolation and identification of the chemical compounds.

Materials and methods

Compounds were isolated from aqueous extract of Remirea maritima through preparative HPLC and the structures were identified by means of NMR and MS analysis. The tests for antinociceptive, anti-inflammatory, and antioxidant activities, along with motor coordination test (Rota rod), were performed over the aqueous extract.

Results

The phytochemical investigation of aqueous extract of Remirea maritima resulted in the isolation of three flavone glycosides. The structures of these compounds were determined by means of MS and 1D and 2D NMR data as vitexin-2″–O-β-d-glucopyranoside, isovitexin-2″–O-β-d-glucopyranoside, and luteolin-7-O-glucuronide. Acute pretreatment with aqueous extract (100, 200 or 400 mg/kg, i.p.) caused a significant decrease (p<0.001) in the number of abdominal writhes. In the formalin test, higher doses significantly inhibited the late (inflammatory pain) phase of formalin-induced licking (p<0.05 or 0.001). In the hot plate test, there was no significant difference in nociceptive behavior, discarding the possible central effect of the aqueous extract. In the rota rod test, it was verified that the aqueous extract in all concentration evaluated does not alter the motor coordination of mice, such antinociceptive results were unlikely to be caused by motor abnormality. In the peritonitis test, induced by carrageenan, the treatment with aqueous extract produced a significant reduction in leukocyte migration in all concentration evaluated. Additionally, a significant reduction of lipoperoxidation (TBARS test) and in nitric oxide formation (.NO Scavenging assay) was observed in antioxidant activity assay.

Conclusion

The biological and phytochemical investigations of the aqueous extract of Remirea maritima resulted in the identification of three flavone glycosides that have been described here for the first time in Remirea and effective analgesic activity in various pain models, probably mediated via the inhibition of peripheral mediators which could be related to its strong antioxidant effect observed in vitro.     

Estimation of anti-inflammatory,antinociceptive and antioxidant activities on Arctium minus (Hill) Bernh. ssp. minus

Ethnopharmacological relevance

Arctium minus (Hill) Bernh. ssp. minus (Asteraceae) leaves are used to alleviate rheumatic pain, against fever and sunstroke with externally application in Turkish folk medicine.

Aim of the study

To evaluate the anti-inflammatory, antinociceptive and antioxidant activities of aqueous and ethanol extracts prepared from the leaves of Arctium minus ssp. minus.

Materials and methods

The ethanolic and aqueous extracts from the leaves of Arctium minus ssp. minus were evaluated in mice for anti-inflammatory activity using carrageenan-induced hind paw edema model and for antinociceptive activity using p-benzoquinone-induced abdominal contractions test. Moreover, the antioxidant power of the extracts has been determined by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and flow injection analysis-luminol chemiluminescence (FIA-CL). In addition, the total phenolic content in both extracts was determined with spectrophotometric method.

Results

Our results showed that only the ethanol extract exhibited a dose-dependent anti-inflammatory activity ranging between 11.1 and 23.6% at 200 mg/kg dose as well as displayed a significant antinociceptive activity without inducing any gastric damage. Although, both extracts were shown to possess significant DPPH radical-scavenging activity, that of aqueous extract was found to have more pronounced activity. In FIA-CL system, the ethanol extract was shown to possess a significant scavenger activity against H₂O₂ while the aqueous extract was much more potent antioxidant activity against HOCl-luminol CL than ethanol extract.

Conclusion

According to our results, it was concluded that Arctium minus ssp. minus contains potent natural antioxidants. In this study, in vivo experimental results have also supported the folk medicinal utilization of Arctium minus ssp. minus.     

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.     

Bioguided isolation of myricetin-3-O-β-galactopyranoside with antinociceptive activity from the aerial part of Davilla elliptica St.-Hil

Ethnopharmacological relevance

Davilla elliptica St.-Hil. (Dilleniaceae) is a medicinal plant traditionally used in Brazil to treat inflammatory processes, to relieve pain, as diuretic, gastro- and hepatoprotective agents.

Aim of the study

To undertake the fractionation of the ethanolic extract from Davilla elliptica leaves guided by an antinociceptive assay.

Materials and methods

The antinociceptive activity was evaluated through the formalin test in mice. Extract fractionation was performed by percolation through silica gel and partition between immiscible solvents, followed by successive column chromatography over Sephadex LH-20 and preparative RP-HPLC. Structure elucidation of the isolated compound was accomplished by spectroscopic data.

Results

The EtOAc and MeOH fractions derived from the crude extract reduced significantly the licking time in the late phase of the formalin test. The bioguided fractionation of the MeOH fraction resulted in the isolation of myricetin-3-O-β-galactopyranoside, which produced significant inhibition on nociception induced by formalin (ID₅₀=0.26 mg/kg; p.o.).

Conclusions

These results point out that myricetin-3-O-β-galactopyranoside contributes for the antinociceptive effect of Davilla elliptica extract, a constituent considerably more potent than diclofenac, employed as reference drug.     

Anti-inflammatory and analgesic effects of ethanol and aqueous extracts of Pterocephalus hookeri (C.B. Clarke) Höeck

Aim of the study

This study evaluates the anti-inflammatory and analgesic activities of the ethanol and aqueous extracts of a Tibetan herb Pterocephalus hookeri (C.B. Clarke) Höeck to provide experimental evidence for its traditional use such as cold, flu and rheumatoid arthritis.

Materials and methods

Investigations on the analgesic effects of P. hookeri (C.B. Clarke) Höeck were carried out, including hot-plate test and acetic acid-induced writhing. The anti-inflammatory activities were observed by utilizing the following models: carrageenin-induced edema of the hind paw of rats, cotton pellet-induced granuloma formation in rats, acetic acid-induced permeability, and xylene-induced ear edema in mice. The effects of the administration of indomethacin were also studied.

Results

It has been shown that the ethanol and aqueous extracts significantly increased the hot-plate pain threshold and reduced acetic acid-induced writhing response in mice. The ethanol and aqueous extracts remarkably inhibited the increase in vascular permeability induced by acetic acid and ear edema induced by xylene. The ethanol extract also significantly decreased the carrageenin-induced rat paw edema perimeter and inhibited the increase of granuloma weight.

Conclusion

The results show that the ethanol and aqueous extracts have both central and peripheral analgesic activities and as anti-inflammatory effects, supporting the traditional application of this herb in treating various diseases associated with inflammation and pain.     

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

Ethnopharmacological relevance

In 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 methods

ICR 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.

Results

Administration 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 50 mg/kg; i.p.) and the acetic acid-induced writhing (25 and 50 mg/kg; i.p.) tests. No effects were however observed both in the elevated plus-maze and hole board test (3.2, 12.5 and 25 mg/kg; i.p.). In contrast, both locomotion (open field test) and motor coordination (rotarod test) were affected at doses (50, 100 y 200 mg/kg; i.p.) higher than those having antinociceptive effects.

Conclusion

These 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.     

Evaluation of the antinociceptive and anti-inflammatory effect of Caralluma dalzielii

Ethnopharmacological relevance

Caralluma dalzielii has been used for treating several ailments including convulsion, leprosy, snake bites, otitis (ear pain), fungal diseases and rheumatoid arthritis in Northern Nigeria. However there is no scientific evidence to support its use in literature. To evaluate the antinociceptive and anti-inflammatory properties of the aqueous extract of Caralluma dalzielii in animal models.

Materials and methods

The antinociceptive and anti-inflammatory properties were assessed using acetic acid induced writhing test in mice, sub plantar formalin induced nociception, the tail-flick test and formalin induced oedema in rats. Three doses of the extract (25, 50, 100 mg/kg) were used for the assessment.

Results

Caralluma dalzielii extract demonstrated strong dose-dependent antinociceptive and anti-inflammatory activities in all the models employed. All doses (25, 50, 100 mg/kg) produced a significant percentage inhibition (41.77, 77.11, and 90.76% in the early phase and 52.02, 85.35, 93.93% in the late phase) in the acetic acid writhing test and (42.85, 55.71, 86.43% in the early phase and 23.26, 37.98, 72.87 in the late phase) in the formalin induced nociception test, respectively. The tail-flick test showed a significant increase in the antinociceptive effect of the extract in both early and late phases when compared with the control. The inhibition of oedema in the formalin test was significant when compared to the control.

Conclusion

The results indicated that Caralluma dalzielii showed excellent antinociceptive and anti-inflammatory properties suggesting that its traditional use in the treatment of pains and inflammatory diseases may be valid.     

Anti-inflammatory and antinociceptive properties of the leaves of Eriobotrya japonica

Aim of the study

The leaves of Eriobotrya japonica Lindl. have been widely used as a traditional medicine for the treatment of many diseases including coughs and asthma. The present study was designed to validate the anti-inflammatory and antinociceptive properties of the n-BuOH fraction of E. japonica (LEJ) leaves.

Materials and methods

The anti-inflammatory properties of LEJ were studied using IFN-γ/LPS activated murine peritoneal macrophage model. The antinociceptive effects of LEJ were assessed using experimental models of pain, including thermal nociception methods, such as the tail immersion test and the hotplate test, and chemical nociception induced by intraperitoneal acetic acid and subplantar formalin in mice. To examine the possible connection of the opioid receptor to the antinociceptive activity of LEJ, we performed a combination test with naloxone, a nonselective opioid receptor antagonist.

Results

In the IFN-γ and LPS-activated murine peritoneal macrophage model, LEJ suppressed NO production and iNOS expression via down-regulation of NF-κB activation. It also attenuated the expression of COX-2 and the secretion of pro-inflammatory cytokines like TNF-α and IL-6. Moreover, LEJ also demonstrated strong and dose-dependent antinociceptive activity compared to tramadol and indomethacin in various experimental pain models. In a combination test using naloxone, diminished analgesic activities of LEJ were observed, indicating that the antinociceptive activity of LEJ is connected with the opioid receptor.

Conclusions

The results indicate that LEJ had potent inhibitory effects on the inflammatory mediators including nitric oxide, iNOS, COX-2, TNF-α and IL-6 via the attenuation of NF-κB translocation to the nucleus. LEJ also showed excellent antinociceptive activity in both central and peripheral mechanism as a weak opioid agonist. Based on these results, LEJ may possibly be used as an anti-inflammatory and an analgesic agent for the treatment of pains and inflammatory diseases.     

Antinociceptive activity of Amaranthus spinosus in experimental animals

Aim of the study

50% ethanol extract (ASE) of Amaranthus spinosus (whole plant) has been evaluated for antinociceptive and antiinflammatory activities.

Materials and methods

Analgesic and antiinflammatory activities were studied by measuring nociception by formalin, acetic acid, hot plate, tail immersion method while inflammation was induced by carrageenan.

Results

ASE had significant dose dependent percentage protection against acetic acid (0.6% of 10 ml) induced pain and the effects were also compared to aspirin, morphine and naloxone while formalin induced pain (0.05 ml of 2.5%) was significantly blocked only at higher dose (400 mg/kg) in first phase. ASE significantly blocked pain emanating from inflammation at all the doses in second phase. The reaction time in hot plate was increased significantly and dose dependently where as pretreatment with naloxone rigorously reduced the analgesic potentials of ASE. Further in tail immersion test the same dose dependent and significant activity was observed. Aspirin had no effect on thermal induced pain i.e. hot plate and tail immersion tests but showed an effect on writhing test.

Conclusions

Our investigation show that Amaranthus spinosus possess significant and dose dependant antiinflammatory activity, it has also central and peripheral analgesic activity.     

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.     

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

Ethnopharmacological relevance

Anadenanthera 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 methods

The AE of Anadenanthera colubrina, made from the bark, was used in rodents via oral route (p.o.), at 100, 200, and 400 mg/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).

Results

The acetic acid-induced abdominal writhes in mice were significantly reduced (P<0.001) by oral treatment with the extract (100, 200, and 400 mg/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 400 mg/kg, P<0.01). The carrageenan-induced peritonitis was significantly reduced (P<0.05) by the aqueous extract at 100, 200, and 400 mg/kg. The aqueous extract (200 mg/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.

Conclusions

We 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.     

Characterization of the antinociceptive and anti-inflammatory activities from Cocos nucifera L. (Palmae)

Aim of the study

Cocos nucifera cultivated in Brazil is known as “coco-da-Bahia” or “coqueiro-da-Índia”. The tea from the husk fiber is widely used to several inflammatory disorders. Crude extract and fractions obtained from Cocos nucifera “common variety” were evaluated to test the anti-inflammatory and antinociceptive activities.

Materials and methods

Crude extract (CE, 50, 100, and 150 mg/kg), fraction 1 (F1, molecular weight lesser than 1 kDa, 1, 10, and 50 mg/kg), fraction 2 (F2, molecular weight higher than 1 kDa, 1, 10, and 50 mg/kg), and the references drugs morphine (5 mg/kg), acetilsalicilic acid (200 mg/kg), prometazine (30 mg/kg), and metisergide (5 mg/kg) were evaluated on models of analgesia and inflammation.

Results

CE, F1, and F2 significantly develop peripheral and central antinociceptive activity but with less effect on supra-spinal regions of the brain. Administration of the opioid antagonist, naloxone (5 mg/kg) inhibited the antinociceptive effect indicating that Cocos nucifera crude extract and fractions may be acting in opioid receptors. CE and F1 also inhibited rat paw edema induced by histamine, and serotonin.

Conclusions

results demonstrated that Cocos nucifera and its fractions have antinociceptive and anti-inflammatory activities which confirm the popular use of this plant in several inflammatory disorders.     

Studies on the analgesic,anti-inflammatory and antipyretic effects of Parquetina nigrescens leaf extract

Ethnopharmacological relevance

Parquetina nigrescens is a shrub that is commonly used in different parts of West Africa for the treatment of several ailments which includes pain, fever and inflammatory conditions.

Aim of the study

The present study was designed to investigate the analgesic, anti-inflammatory and antipyretic effects of the aqueous extract of Parquetina nigrescens leaves in rats.

Materials and methods

Five groups were used for each study, groups 1 and 5 served as control (saline) and reference (indomethacine) respectively, while groups 2–4 received the extract (50–200 mg/kg) orally. Formalin paw licking and hot plate latency tests were used for analgesic studies. Carrageenan oedema, cotton pellet granuloma and formaldehyde arthritis models were used to quantify the anti-inflammatory activities while the brewer’s yeast was used for inducing pyrexia.

Results

The results of the analgesic study show that the extract produced significant (p < 0.05) analgesia in the hot plate and in the formalin tests. In the anti-inflammatory study, Parquetina nigrescens produced significant (p < 0.05) inhibition of the various types of inflammation. The extract also inhibited the pyrexia induced by brewer’s yeast.

Conclusion

The result justifies the traditional uses of Parquetina nigrescens for the treatment of fever, inflammatory and painful conditions.     

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.