Effects of Lecythis pisonis Camb. (Lecythidaceae) in a mouse model of pruritus

Ethnopharmacological relevance

Lecythis pisonis Camb. (Lecythidaceae), is popularly known as “Sapucaia”. In traditional medicine, leaves are used for the treatment of pruritus.

Aim of the study

The present study is aimed to investigate the antipruritic effect of the ethanol extract from leaves of Lecythis pisonis (LPEE), fractions (hexane-LPHF, ether-LPEF and ethyl acetate-LPEAF) and mixture of triterpenes [ursolic and oleanolic acids (MT)] in mice and rats.

Materials and methods

The LPEE, LPHF, LPEF, LPEAF and MT were evaluated on scratching behavior induced by compound 48/80 in mice. In addition, LPEE, LPEF and MT were investigated on rat peritoneal mast cells degranulation induced by compound 48/80 (ex vivo study). The anti-inflammatory activity of LPEE and LPEF was investigated in rats using carrageenan-induced hind paw edema model. In the evaluation of the spontaneous motor activity, the LPEE was studied for its effect on spontaneous motor activity in an open-field test in mice.

Results

The scratching behavior induced by compound 48/80 was significantly inhibited in mice pretreated with LPEE, LPHF, LPEF, LPEAF and MT. The suppressive effect of LPEE, LPEF and MT was only partially antagonized by naloxone. In addition, the compound 48/80-elicited degranulation of rat peritoneal mast cells was also markedly reduced in animals pretreated with LPEE, LPEF and MT. In the anti-inflammatory test, LPEE decreased the paw edema at the third hour after carrageenan (Carr) administration. Moreover, LPEF also was able to inhibit the oedematogenic response evoked by carr at all analysed time points. In the open-field test, LPEE-pretreated mice showed no impairment of spontaneous locomotion. Furthermore, the LPEE demonstrated no overt toxicity up to an oral dose of 2 g/kg in an acute toxicity assay.

Conclusions

These results clearly indicate the antipruritic effects of Lecythis pisonis leaves and suggest that this effect may be related to a stabilizing action on mast cell membrane. Furthermore, these data support the traditional use of this plant against cutaneous pruritus.     

The antinociceptive and anti-inflammatory activities of Piptadenia stipulacea Benth. (Fabaceae)

Aim

In this study, we attempted to identify the possible antinociceptive and anti-inflammatory actions of the aqueous phase, the ethyl acetate phase and one unknown flavonoid obtained from aerial parts of Piptadenia stipulacea, known in Brazil as “jurema-branca”, “carcará” and “rasga-beiço”.

Materials and methods

Aerial parts of Piptadenia stipulacea were used and after fractionation, the flavonoid FGAL was obtained. Experiments were conducted on Swiss mice using the acetic acid-induced writhing test, the hot plate test, the formalin-induced pain test and zymosan A-induced peritonitis test.

Results

The aqueous and ethyl acetate phases (p.o., 100 mg/kg); and the flavonoid FGAL (p.o. and i.p. at 100 μmol/kg), reduced the nociception produced by acetic acid, by 49.92%, 54.62%, 38.97% and 64.79%, respectively. In vivo inhibition of nociception by the ethyl acetate phase (100 mg/kg, p.o.) in the hot plate test was favorable, indicating that this fraction exhibited central activity. The ethyl acetate phase (100 mg/kg, p.o.) reduced the formalin effects in both phases by 28.51% and 55.72%, respectively. Treatment with the aqueous phase (100 mg/kg, p.o.) and FGAL (100 μmol/kg, i.p.) only protected the second phase by 69.76% and 68.78%, respectively. In addition, it was observed in the zymosan A-induced peritonitis test that the aqueous phase, the ethyl acetate phase and the FGAL exhibited anti-inflammatory activity, reducing significantly the number of recruit cells by 35.84%, 37.70% and FGAL (1), respectively.

Conclusions

These data demonstrate that the FGAL elicits pronounced antinociceptive activity against several pain models. The actions of this flavonoid probably are due to antioxidative properties. However, pharmacological and chemical studies are continuing in order to characterize the mechanism(s) responsible for this antinociceptive action and also to identify other active substances present in Piptadenia stipulacea.     

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.     

Involvement of glutamate and cytokine pathways on antinociceptive effect of Pfaffia glomerata in mice

Ethnopharmacological relevance

Pfaffia glomerata (Spreng) Pedersen (Amaranthaceae) is a medicinal plant known in Brazil as “Paratudo” and “Brazilian ginseng” and is commonly used as tonic, antidiabetic and to treat gastric disorders.

Aim of the study

This study evaluates the possible mechanism by which hydroalcoholic extract (HE) of Pfaffia glomerata exerts its antinociceptive effect.

Materials and methods

The HE was evaluated in acetic acid and glutamate models of pain or by biting behavior following intrathecal (i.t.) administration of agonists of excitatory aminoacids (EAA) receptors glutamate and pro-inflammatory cytokines, IL-1β and TNF-α in mice.

Results

Oral administration of HE produced dose-dependent inhibition of acetic acid-induced visceral pain and glutamate-induced pain, with ID₅₀ of 64.6 (47.7–87.5) mg/kg and ID₅₀ of 370.8 (253.4–542.7) mg/kg, respectively. The HE (300 mg/kg, p.o.) antinociception, in the acetic acid test, was not affected by i.p. treatment of animals with naloxone. In addition, HE (300 mg/kg, p.o.) inhibited the pain-related behaviors induced by i.t. injection of trans-ACPD and TNF-α, but not by NMDA, AMPA, kainate or IL-1β.

Conclusions

Our results suggest that inhibition of glutamatergic metabotropic receptors and TNF-α may account for the antinociceptive action reported for the HE in models of chemical pain used in this study.     

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.     

Characterisation of the anti-inflammatory and antinociceptive activities of the Hyptis pectinata (L.) Poit essential oil

Aim of the study

Hyptis pectinata Poit (Lamiaceae) is grown in the northeastern regions of Brazil and is popularly known as “sambacaitá” or “canudinho”. It is extensively used in folk medicine to treat inflammatory conditions, bacterial infections, pain, and cancer.

Materials and methods

Hyptis pectinata essential oil (EO, 10, 30, and 100 mg/kg, p.o.) and the reference drugs morphine (5 mg/kg, p.o.) and acetylsalicylic acid (ASA, 200 mg/kg, p.o.) were evaluated using models for analgesia (acetic acid-induced contortions and hot plate) or inflammation (formalin-induced licking response and the subcutaneous air-pouch model). To elucidate the EO's mechanism of action, animals were pre-treated with the opioid receptor antagonist naloxone (1 mg/kg, i.p.), the cholinergic antagonist atropine (1 mg/kg, i.p.), or l-nitro arginine methyl ester (l-NAME, 3 mg/kg, i.p.) 30 min prior to the oral administration of the EO.

Results

The EO significantly inhibited the number of writhings and the time the animals spent licking their formalin-injected paws (second phase). The EO, at doses of 30 and 100 mg/kg, increased baseline measurements and area under the curve measurements in the hot plate model, respectively. The administration of naloxone reversed the antinociceptive effect of the EO in the hot plate model. l-NAME significantly reversed the effects of the EO in the contortions and hot plate models. Atropine completely reversed the antinociceptive activity of the EO in all models. Additionally, the EO inhibited the inflammatory process induced by subcutaneous carrageenan injection by reducing cell migration, exudate volume, protein concentration, and inflammatory mediators (nitric oxide, prostaglandin E2, IL-6, and TNF-α) produced in the pouch.

Conclusions

Our results indicate that the Hyptis pectinata essential oil exhibits antinociceptive effects, likely mediated by opioid and cholinergic receptors, and anti-inflammatory activity through the inhibition of nitric oxide and PGE2 production.     

Characterization of the antinociceptive and anti-inflammatory activities of fractions obtained from Copaifera multijuga Hayne

Ethnopharmacological relevance

Copaifera multijuga Hayne (Leguminosae) is a tree that produces an oleoresin, which is extensively commercialized in Brazil as capsules or crude oil for the treatment of several disorders. Ethnopharmacological studies show a diversity of indications such as anti-inflammatory and epidermal wound cicatrization.

Aim of the study

In the present work three fractions obtained from Copaifera multijuga oleoresin (hexane (HF), chloroform (CF), and methanol (MF) from a KOH impregnated silica gel column chromatography, representing the three main classes of compounds in the Copaifera genus (hydrocarbon sesquiterpenes, oxygenated sesquiterpenes and acidic diterpenes), were evaluated using antinociceptive and anti-inflammatory models.

Materials and methods

HF, CF, and MF (doses ranging between 1 and 150 mg/kg, depending on the model used), Copaifera multijuga oleoresin (CMO, 100 mg/kg, p.o.) and the reference drug morphine (5 mg/kg, p.o.) were evaluated using models for analgesia (acetic acid-induced contortions and tail flick) or inflammation (rat paw oedema and increase in vascular permeability). To elucidate the mechanism of action from the fractions, animals were pre-treated with naloxone (opioid receptor antagonist, 5 mg/kg, i.p.).

Results

Fractions significantly inhibited (in a concentration-dependant way) the number of contortions induced by acetic acid and the second phase of formalin-induced licking response. Similar results were observed in the tail flick model. The central antinociceptive effect for HF and CF at the doses of 50 and 100 mg/kg was higher than the one observed for morphine (1 mg/kg). Administration of naloxone inhibited the antinociceptive effect of fractions indicating that HF, CF, and MF may be acting on opioid receptors. All three fractions also inhibited rat paw oedema and the increase in vascular permeability induced by several phlogistic agents (carrageenan, histamine, and serotonin).

Conclusions

Our results indicate that fractions obtained from Copaifera multijuga Hayne demonstrate an antinociceptive effect probably mediated by opioid receptors, and anti-inflammatory activity through inhibition of histaminergic and serotoninergic pathways.     

Antinociceptive effect of Mirabilis jalapa on acute and chronic pain models 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. Thus, the present study was designed to investigate whether the leaf ethyl acetate (Eta) fraction from Mirabilis jalapa exhibits antinociceptive effect in clinically relevant pain models in mice. Furthermore, we have investigated the role of cholinergic system in the antinociceptive action produced by Eta in mice.

Materials and methods

The effect of Eta administered orally (10 mg/kg, p.o.) in mice was verified on the painful hypersensitivity (mechanical allodynia) in models of chronic inflammation (subcutaneous injection of complete Freund’s Adjuvant—CFA in the plantar surface of the right hind paw), postoperative (paw surgical incision) and neuropathic (partial sciatic nerve ligation) pain. In the chronic inflammation model, we further verified the effect of Eta treatment on paw edema and interleukin-1β (IL-1β) levels. We also investigated the role of muscarinic and nicotinic receptors in the antiallodynic action produced by Eta as well as the possible action of Eta on in vitro and ex vivo acetylcholinesterase activity in CFA treated animals. Furthermore, we verified the effect of Eta treatment on the parameters of liver and kidney lesion (level of urea, and activity of aspartate aminotransferase and alanine aminotransferase).

Results

Eta produced marked reduction in the allodynia caused by CFA, surgical incision and partial sciatic nerve ligation. However, Eta did not alter the paw edema or the increase of IL-1β levels produced by CFA. The antinociceptive effect of Eta was reversed by the pre-treatment of animals with the antagonists of muscarinic (atropine, 5 mg/kg, s.c) or nicotinic (mecamylamine, 0.001 mg/kg, s.c.) receptors. Eta did not alter in vitro acetylcholinesterase activity in blood or spinal cord samples, but it reversed the increase in the acetylcholinesterase activity observed in the spinal cord samples from mice injected with CFA. Moreover, Eta did not alter the indicators of liver or kidney lesion.

Conclusions

Based on its use in traditional medicine, the results of the present study confirmed the antinociceptive properties of Eta in clinically relevant pain models. Also its effect on the CFA-induced chronic inflammation seems to be related to acetylcholinesterase inhibition and cholinergic system.     

Analgesic and anti-inflammatory effects of Pistacia integerrima extracts in mice

Aim of study

Extracts of Pistacia integerrima galls have been dispensed by Traditional Practitioners of Subcontinent for chest diseases as well as for aches and pains in the body. This study was planned to evaluate the possible analgesic and antiinflammatory effects of Pistacia integerrima extracts.

Materials and methods

Analgesia was determined using acetic acid induced abdominal constriction and formalin induced paw licking in mice. Antinociceptive effect was observed by thermally induced algesia in mice.

Results

Pistacia integerrima leaves extracts showed significant response against chemically induced pain (P < 0.001) whereas galls extracts had highly significant protection (P < 0.0001) in a dose dependent manner. In thermally induced algesia, Pistacia integerrima galls extracts 200 mg/kg (p.o.), showed significant (P < 0.05) response but less than pentazocine and diclofenac, positive references. The extracts of Pistacia integerrima 50–200 mg/kg (p.o.) had modest activity against hind paw acute and chronic inflammation induced by formalin (P < 0.01).

Conclusion

These results demonstrate that Pistacia integerrima extracts have antinociceptive and analgesic effects and no apparent acute toxicity on oral administration.     

Chemical composition and antinociceptive effect of aqueous extract from Rourea induta Planch. leaves in acute and chronic pain models

Ethnopharmacological relevance

Rourea induta Planch. is a small tree or shrub growing wild in Brazil and belonging to the Connaraceae family. It is used for the treatment of Chagas disease and as antirheumatic in folk medicine. This study was designed to investigate the antinociceptive activity of the aqueous extract (AERi) of Rourea induta leaves in rodents, as well as isolate and identify components that can be responsible for its effect.

Material and methods

The antinociceptive effect of orally administered AERi was evaluated in behavioral models of acute (formalin) and chronic [complete Freund?s adjuvant (CFA)] pain in mice. We also investigated the possible involvement of opioid receptors and proinflammatory cytokines (interleukin-1β and tumor necrosis factor-α) in the antinociceptive effect of the AERi. In addition, a nonspecific effect of AERi was evaluated by measuring locomotor activity and corporal temperature. Finally, we performed a phytochemical analysis of AERi.

Results

HPLC titration revealed the presence of hyperin (21.6 mg/g), quercetin-3-O-β-xyloside (4.4 mg/g), quercetin-3-O-α-arabinofuranoside (12.0 mg/g), and quercetin (2.1 mg/g). It was also possible to isolate minor constituents? chlorogenic acid, neochlorogenic acid and procyanidin C1. The oral administration of AERi (100 mg/kg) significantly inhibited the neurogenic (37±5%) and inflammatory (34±7%) phases of formalin-induced pain. Acute and repeated treatment of animals with AERi (100 mg/kg, p.o.) once a day markedly reduced the mechanical hypersensitivity response induced by CFA, and this effect was evident until the day 10. Moreover, repeated treatment with AERi (100 mg/kg, p.o.) significantly reduced the levels of IL-1β and TNF-α in the paw (22±7% and 50±19%) and in the spinal cord (100% and 100%) when compared to the CFA group. The AERi (100 mg/kg, p.o.) markedly reduced biting behavior induced by intrathecal injection of TNF-α (81±11%). Finally, the effect of AERi was not associated with changes in locomotor activity or the corporal temperature of animals.

Conclusion

These data show that aqueous extract of Rourea induta has significant antinociceptive action, which seems to be associated with an inhibition of pro-inflammatory cytokines activated pathways. These findings support the ethnomedical uses of this plant.