Analgesic properties of the aqueous and ethanol extracts of the leaves of Kalanchoe crenata (Crassulaceae)

The aqueous and ethanol extracts of the dry leaves of Kalanchoe crenata (300 and 600 mg/kg) were evaluated for their analgesic properties on the pain induced by acetic acid, formalin and heat in mice and by pressure on rats. The ethanol extract of K. crenata at a dose of 600 mg/kg produced an inhibition of 61.13% on pain induced by acetic acid and 50.13% for that induced by formalin. An inhibition of 67.18% was observed on pain induced by heat 45 min after the administration of the extract. The aqueous extract administered at a dose of 600 mg/kg produced a maximum effect of 25% on pain induced by pressure. These activities were similar to those produced by a paracetamol-codeine association, while indomethacin exhibited a protective effect only against the writhing test. Our results suggest that the leaves of K. crenata could be a source of analgesic compounds.     

Antipruritic and antinociceptive effects of Chenopodium album L in mice

The ethanolic extract from the fruits of Chenopodium album L. (FCAL), orally administered at doses of 100-400 mg/kg, dose-dependently inhibited scratching behavior induced by 5-HT (10 micro g per mouse, s.c.) or compound 48/80 (50 micro g per mouse, s.c.) in mice. But it failed to affect hind paw swelling induced by 5-HT or compound 48/80 in mice at doses of 100 and 200 mg/kg and only showed a relatively weak inhibition on the swelling at a higher dose of 400 mg/kg. In addition, FCAL (200 and 400 mg/kg) significantly attenuated the writhing responses induced by an intraperitoneal injection of acetic acid and the inflammatory pain response induced by an intraplantar injection of formalin in mice. At a dose of 400 mg/kg, it also inhibited the neurogenic pain response of formalin test. In conclusion, FCAL possesses antipruritic and antinociceptive activities and the antinociceptive effects are not secondary to anti-inflammatory effects. The findings support evidence for the clinical use of FCAL to treat cutaneous pruritus.     

Investigations on the antinociceptive effect of Psidium guajava leaf essential oil and its major constituents

The antinociceptive effect of leaf essential oil from Psidium guajava and its major constituents, β-caryophyllene and α-pinene was assessed using chemical (formalin and acetic acid) and thermal (hot-plate) nociceptive tests in adult male albino mice. Oral administration of 100, 200 and 400 mg/kg of essential oil produced a significant antinociceptive effect in the formalin test and at 200 and 400 mg/kg in the acetic acid- induced writhing test. Of the major components only α-pinene, but not the β-caryophyllene, demonstrated significant antinociception in the formalin test. Neither the essential oil nor the major components could exert any significant effect in the hot-plate test. Pretreatment of mice with caffeine (20 mg/kg, i.p.), significantly inhibited the antinociceptive effect of essential oil in the formalin test. Naloxone (1 mg/kg, s.c.), the opioid antagonist, however, failed to antagonize it. These results suggest that the antinociceptive effect of P. guajava essential oil is probably mediated by endogenously released adenosine. © 1998 John Wiley & Sons, Ltd.     

Antinociceptive and anti-inflammatory potential of extract and isolated compounds from the leaves of Salvia officinalis in mice

Ethnopharmacological relevance

Salvia officinalis L. has been used as a traditional herbal medicine for gastric disturbances and inflammatory processes. This study investigated the toxicological, antinociceptive and anti-inflammatory effects of the hydroalcoholic extract (HE) from leaves of Salvia officinalis and its isolated compounds in mice.

Materials and methods

Mice were treated with HE before the induction of nociceptive response by chemical agents (acetic-acid, formalin, glutamate, capsaicin and cinnamaldehyde). Total leukocytes and plasma extravasation induced by acetic acid and paw oedema induced by glutamate, capsaicin and cinnamaldehyde were also measured. The antinociceptive effect of carnosol and ursolic acid/oleanolic acid were evaluated on formalin and cinnamaldehyde models.

Results

In the acute toxicity test the value of estimated LD50 for HE was 44.7579 g/kg. Oral administration of HE (10, 30 and 100 mg/kg) inhibited the number of writhings, total leukocytes and plasma extravasation induced by acetic acid. In the formalin test, HE reduced both neurogenic and inflammatory phases, effect that was affected by naloxone. The glutamate-, capsaicin- and cinnamaldehyde-induced nociception and paw oedema were reduced by HE at doses that did not affect the locomotor activity of mice in the open field test. Carnosol (10 mg/kg) and ursolic acid/oleanolic acid (30 mg/kg) inhibited the inflammatory phase of formalin and the nociception and mechanical allodynia induced by cinnamaldehyde.

Conclusions

These results demonstrate that HE presents significant anti-inflammatory and also antinociceptive effects on chemical behavioral models of nociception that involves an opioid mechanism. In addition, carnosol and ursolic acid/oleanolic acid contained in this plant appears to contribute for the antinociceptive property of the extract, possibly through a modulatory influence on TRPA1-receptors. However, further studies regarding the precise site and the mechanism of action of HE and carnosol and ursolic acid/oleanolic acid merited exploring further.     

Antinociceptive and antidepressant like effects of Securidaca longepedunculata root extract in mice

The aqueous root extract of Securidaca longepedunculata (polygalaceae) was investigated for possible antinociceptive and central nervous system (CNS) effects in mice. Three nociceptive models; acetic acid, formalin and tail-flick tests were used to study the antinociceptive activity. Rectal temperature test was employed as an adjunct to the nociceptive models. The extract at 200 and 400 mg/kg significantly and dose dependently reduced the nociception induced by the acetic acid and in the early phase of formalin test (P<0.05). The extract exerted significant (P<0.05) hypothermic effect in the 15 and 30 min of the rectal temperature test. The antinociceptive and hypothermic effects were partially reversed by naloxone (1mg/kg). The tail-flick test produced an insignificant increase in tail-flick latency at 400 mg/kg after 60 min of the test, but significantly (P<0.05) increase tail-flick latency in the 400mg/kg group of animals pre-treated with naloxone (1 mg/kg) after 120 min of the test. The extract also produced a significant (P<0.05) naloxone reversible antidepressant like effect in the forced swimming test (an animal model of depression). Collectively, these results suggest that the extract possess antinociceptive and antidepressant like effects with possible involvement of opioidergic pathways. The extract at limit dose of 2 g/kg body weight appeared to be safe in oral formulation.     

Antinociceptive activity of aqueous extract of Pachyptera hymenaea (DC.) in mice

The standardized aqueous extract of leaves of Pachyptera hymenaea (DC.) belonging to family Bignoniaceae was investigated for possible antinociceptive effect in mice. Three different models were used to study the effects of extract on nociception, namely acetic acid-induced writhing test, formalin test (paw licking test) and tail flick test in mice. The extract was administered 1h prior to pain induction in the dose range of 25, 50 and 75mg/kg orally. The extract at the given dose range reduced the acetic acid induced nociception by 44.03, 52.90 and 62.46% respectively. The extract reduced formalin effect in both the phases of experiment by 32.36, 41.94, 54.29% and 35.39, 50.17, 55.86% respectively. In the tail flick study, animals' reaction time were increased by 22.69, 38.24 and 40.26% at the above selected doses respectively at 120min after drug administration. Naloxone (2mg/kg; s.c.) significantly antagonized the effect of extract in formalin and tail flick method, while partially antagonized the effect in writhing test. However caffeine completely reverted the extract effect in both the phases of formalin test. Results of these studies revealed that the extract have significant antinociceptive activity in the used models with a possible involvement of central mechanism and adenosine system.     

Analgesic and anti-inflammatory activity of Crinum glaucum aqueous extract.

The anti-inflammatory and analgesic effects of the aqueous extract of Crinum glaucum were evaluated in mice and rats using the carrageenan- and dextran-induced paw oedema, acetic acid-induced writhing, cold water tail flick and formalin pain tests. The extract (100-400 mg/kg) and acetylsalicylic acid (100 mg/kg) produced a significant (P<0.05) inhibition of the second phase response in the formalin pain model, while only the high dose (400 mg/kg) of the extract showed an antinociceptive effect in the first phase. The extract also showed a dose-dependent inhibition of acetic acid-induced abdominal writhes. The tail flick latency was dose dependently enhanced by the extract but this was significantly (P<0.05) lower than that produced by morphine (2 mg/kg). The extract (125-500 mg/kg) administered 1 h before or after carrageenan-induced paw swelling produced a dose dependent inhibition of the oedema. No effect was observed with the dextran-induced oedema model. The data obtained suggest that the anti-inflammatory and analgesic effects of the extract may be mediated via both peripheral and central mechanisms.     

The analgesic effect of the methanolic extract of Acanthus montanus

The analgesic effect of the methanolic leaf extract of Acanthus montanus was studied in rats using the cold water tail flick assay, and in mice using the tail immersion, tail clip, acetic acid induced writhing and formalin pain tests. The results showed dose-dependent and significant (P<0.05) increases in pain threshold, at 60 min post treatment, with doses of 200 and 400 mg/kg of the extract in tail flick, tail immersion and tail clip methods. The effects of the extract were significantly (P<0.05) lower than those produced by morphine (10 mg/kg) in the same tests. The extract (100-400 mg/kg) exhibited a dose-dependent inhibition of writhing and also showed a significant (P<0.001) inhibition of both phases of the formalin pain test, but with a less intense effect on the first than on the second phase. The results indicate that the analgesic effect of Acanthus montanus methanolic extract is both centrally and peripherally mediated.     

Influence of piperine on nimesulide induced antinociception

Piperine (1-peperoyl piperidine), an alkaloid extracted from Piper nigrum Linn is an inhibitor of hepatic and other enzymes involved in the biotransformation of drugs. In the present study piperine showed a dose dependent synergistic effect on nimesulide induced antinociception, in the acetic acid induced writhing test in mice. Piperine at a dose of 10 mg/kg significantly (p < 0.001) increased the analgesic activity of nimesulide administered at a submaximal dose of 6.5 mg/kg. In the formalin test, nimesulide alone (10 mg/kg, oral) did not modify phase I or nociceptor mediated pain while a combination of nimesulide (10 mg/kg) with piperine (10 mg/kg) significantly decreased it. In phase II or inflammatory pain, duration of formalin induced behaviour was 80 ± 7 s, 61 ± 7.3 s and 5.33 ± 3.3 s in control, nimesulide treated and piperine plus nimesulide treated groups respectively, indicating a synergistic activity of piperine with nimesulide. The antinociceptive effect correlated well with increased plasma concentration of nimesulide. The plasma concentration after oral administration of nimesulide (10 mg/kg) alone was 8.03 ± 0.99 ug/mL. However, when it was administered with piperine (10 mg/kg), the plasma concentration of nimesulide increased to 11.9 ± 0.23 ug/mL. This indicates that piperine inhibits the biotransformation and metabolism of nimesulide leading to significantly (p < 0.05) higher levels of drug in the systemic circulation. The findings of the present study suggest that piperine could be used as a biological enhancer when coadministered with nimesulide. © 1998 John Wiley & Sons, Ltd.     

Antinociceptive and anti-inflammatory effect of the aqueous extract from leaves of Pimenta racemosa var. ozua (Mirtaceae)

The leaves of Pimenta racemosa var. ozua (Urban & Ekman) Landrum L. (Myrtaceae) are used against the pain and the inflammation in popular medicine of the Caribe area. In the present work, the antinociceptive, anti-inflammatory effect, and acute toxicity of the aqueous extract from leaves of Pimenta racemosa have been investigated. The antinociceptive action was assayed in several experimental models in mice: acetic acid, formalin, and hot plate tests. The aqueous extract (125 and 250 mg/kg) significantly and in a dose-dependent manner reduced the nociception induced by the acetic acid intraperitoneal injection (P<0.001). In the formalin test, the extract also significantly reduced the painful stimulus in both phases of the test (P<0.001). On the contrary, the extract neither significantly increased the latency time of licking nor jumping in the hot plate test. In the anti-inflammatory study, the plant also showed an interesting effect. Aqueous extract (125 and 250 mg/kg) orally administered, significantly reduced the carrageenan-induced edema in rat paw at 1, 3, and 5 h (P<0.001). In the TPA test the edema was dose-dependent and significantly reduced by the extract (0.5, 1, and 3 mg per ear) when it was topically applied (P<0.01; P<0.001). The levels of myeloperoxidase enzyme also were reduced in the inflamed tissue by the extract. Acute toxicity also was investigated and the results indicated a moderate toxicity (LD50: 287 +/- 12.9 mg residue/kg; 1.854 +/- 0.083 g plant/kg). These results revealed that the extract from leaves of Pimenta racemosa var. ozua exerts an important antinociceptive activity, associated to an anti-inflammatory effect which to appear be markedly influenced by the inhibition of neutrophil migration into inflamed tissue and that lack of toxic effects at usual doses.     

Evaluation of Antinociceptive Activity of Methanol Extract from Cleome rutidosperma in Mice

Objective Cleome rutidosperma (Capparidaceae), commonly known as “Fringed Spider Flower”, is a medicinal plant found in Southeast Asia. C. rutidosperma is used in folk medicine for diuretic, laxative, analgesic, anti-inflammatory, antipyretic, antimicrobial, anti-oxidant, hypoglycemic, and anthelmintic activities. We have evaluated the anti-nociceptive properties of methanol extract from C. rutidosperma (MECR) in vivo. Methods Thermal method (hot plate test and tail flick test) was induced to judge the anti-inflammatory effect and couple of chemical method also used (formalin induced licking test; writhing test carried by acetic acid) to evaluate analgesic effect. Both of these tests were made over animal models, like mice and rats. Two different doses (100 and 200 mg/kg) were used for each case of test, while morphine sulphate (5mg/kg, ip) was used as reference drug. Results MECR demonstrated the significantly anti-nociceptive activity in the analgesic and anti-inflammatory tests by reducing nociception in mice models (P < 0.001). In the hot-plate and tail-flick tests, MECR significantly elongated the time to response to the thermal stimuli (100 and 200 mg/kg with P < 0.05, 0.001). The remarkable increase in the latency was observed at 90 and 120 min. In acetic acid-induced writhing test and formalin induced licking test for anti-inflammatory activity, MECR at 100 and 200 mg/kg doses exhibited significant (P < 0.001) reduction of writhing and licking response. Conclusion The anti-inflammatory and analgesic effects of C. rutidosperma propose that this effect may be a result of both peripheral and central mechanisms. Further study is required to ensure the proper mechanism of action as well as the active ingredient.     

Antinociceptive Effect of Lupeol: Evidence for a Role of Cytokines Inhibition

The present study investigates the antinociceptive properties of lupeol in models of inflammatory and post‐operative pain, as well as its mechanisms of action. The effects of lupeol were tested against acetic acid‐induced writhing, formalin test, carrageenan‐induced hyperalgesia, and post‐operative pain model. Cytokine levels were determined by ELISA. Mice motor performance was evaluated in the rota rod and open‐field tests. Pre‐treatment of mice with lupeol (5–100 mg/kg IP) produced a dose‐related inhibition of writhing in mice. The maximal antinociception produced by lupeol (60 mg/kg) was unaffected in mice pre‐treated with yohimbine (α2 adrenoceptor antagonist; 2 mg/kg IP), L‐arginine (substrate for nitric oxide synthase; 600 mg/kg IP), glibenclamide (the K_ATP‐channel blocker; 2 mg/kg IP), and methysergide maleate (serotoninergic receptors antagonist; 5 mg/kg IP). Furthermore, lupeol (25–100 mg/kg) inhibited the late phase of formalin test. Pre‐treatment with lupeol (50 and 100 mg/kg) inhibited the hyperalgesia and the local increase in tumor necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β) levels induced by carrageenan. In contrast, lupeol did not inhibit the post‐operative pain. Lupeol‐treated mice did not show any motor performance alterations or apparent systemic toxicity. Our results demonstrate that lupeol has consistent antinociceptive properties during inflammatory pain, but not post‐operative pain, acting through the inhibition of IL‐1β and TNF‐α production. Copyright © 2012 John Wiley & Sons, Ltd.     

Evaluation of the analgesic effect of alkaloid extract of Peganum harmala L.: possible mechanisms involved

The seeds of Peganum harmala L. (Pgh) (Zygophyllaceae) have been used in Moroccan traditional medicine for treatment of a various diseases and to relieve dolorous process. The major objective of this paper was to investigate the mechanism of the analgesia induced by alkaloid extract of Peganum harmala. In the present work, the antinociceptive action was assayed in several experimental models in mice: writhing, formalin, and hot plate tests. The alkaloid extract (12.5 and 25mg/kg) and in a dose-dependent manner significantly reduced the nociception by acetic acid intraperitoneal injection (p<0.001). In the formalin test, the extract also significantly reduced the painful stimulus in both phases of the test (p<0.001). Treatment with the extract when given by (i.p. or i.c.v.) or with morphine (10mg/kg, i.p.) produced a significant increase of the reaction time in hot plate test. These result showed that the alkaloid extract of Pgh contains active analgesic principles acting both centrally and peripherally. Furthermore, this antinociceptive effect has been avoided by naloxone at a dose of 1mg/kg in the first phase of formalin and hot plate tests indicating that this extract act partly through an opioid-mediated mechanism. In conclusion, the alkaloid extract of Peganum harmala seems to have both central and peripheral antinociceptive activities which may be mediated by opioid receptors.     

Antinociceptive and gastroprotective actions of ethanolic extract from Pluchea sagittalis (Lam.) Cabrera

Ethnopharmacological relevance

Pluchea sagittalis, an herbaceous plant widely distributed in South America, is used in folk medicine for the treatment of digestive diseases and inflammation.

Aim of the study

This study was designed to investigate the antinociceptive and gastroprotective effects of the ethanolic extract (EE) of aerial parts from Pluchea sagittalis in rodents.

Materials and methods

The antinociceptive effects of EE was evaluated in mice after oral administration in chemical tests (acetic-acid, glutamate and formalin) or by biting behavior following intrathecal administration of cytokines such as interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in mice. Furthermore, rats were treated with EE and subsequently exposed to acute gastric lesions induced by 80% ethanol. Afterwards the gastric lesion extension and the mucus levels of gastric mucosa were measured.

Results

The oral administration of EE showed a dose-dependent inhibition of acetic acid-induced abdominal constrictions and glutamate-induced pain in mice, with ID₅₀ values of 624.0 (523.0-746.0) mg/kg and 368.0 (216.0-628.0) mg/kg, respectively. In the formalin test, the EE also produced significant inhibition of the inflammatory phase, with an ID₅₀ value of 411.0 (183.0-721.0) mg/kg; however, it was ineffective in the neurogenic phase caused by formalin. In addition, oral treatment with EE caused a significant inhibition of biting behavior induced by i.t. injection of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). The antinociception caused by the EE (300 mg/kg, p.o.) was not reversed by naloxone (1 mg/kg, i.p.) when assessed in the acetic acid writhing test. The EE (300-1000 mg/kg, p.o.) did not affect the motor coordination of animals in an open-field model. Oral treatment with the EE protected rats against gastric lesions induced by ethanol, with an ID₅₀ value of 55.0 (46.6-64.9) mg/kg, and increased the mucus levels of gastric mucosa to levels found in the non-lesioned group.

Conclusions

The mechanism by which the extract produced antinociception still remains unclear, but this effect seems to be primarily related to the modulation or inhibition of the action of pro-inflammatory mediators. Furthermore, these data support, at least in part, the ethnomedical use of Pluchea sagittalis.     

Analgesic and anticonvulsant effects of extracts from the leaves of Kalanchoe crenata (Andrews) Haworth (Crassulaceae)

Kalanchoe crenata Andr. (Crassulaceae) is a fleshy herbaceous plant used in the African traditional medicine as remedies against otitis, headache, inflammations, convulsions and general debility. In the present work, the analgesic effects of methylene chloride/methanol (1:1) (CH(2)Cl(2)/CH(3)OH) extract and its hexane, methylene chloride (CH(2)Cl(2)), ethyl acetate, n-butanol fractions and aqueous residue have been evaluated using acetic acid, formalin and pressure test. The anticonvulsant effects of the CH(2)Cl(2)/CH(3)OH extract were also investigated on seizures induced by pentylenetetrazol (PTZ 70 mg/kg), strychnine sulphate (STN 2.5 mg/kg) and thiosemicarbazide (TSC 50 mg/kg). CH(2)Cl(2)/CH(3)OH extract and its fractions, administered orally at the doses of 150 and 300 mg/kg, exhibited protective effect of at least 30% on the pain induced by acetic acid. The CH(2)Cl(2) fraction at 300 mg/kg showed a maximal effect of 78.49%. The CH(2)Cl(2)/CH(3)OH extract and its CH(2)Cl(2) fraction at the doses of 150 and 300 mg/kg significantly reduced the first phase of pain induced by formalin while the second phase was completely inhibited. The CH(2)Cl(2) fraction produced more than 45% reduction in the sensitivity to pain induced by pressure. The CH(2)Cl(2)/CH(3)OH extract of Kalanchoe crenata significantly increased the latency period in seizures induced by PTZ and significantly reduced the duration of seizures induced by the three convulsant agents. The extract protected 20% of animals against death in seizures induced by TSC and STN. These results suggest a peripheral and central analgesic activities as well as an anticonvulsant effect of the leaves of Kalanchoe crenata.     

Antinociceptive activity of ethanolic extract and isolated compounds of Urtica circularis

Ethnopharmacological relevance

Urtica circularis (Hicken) Sorarú is a medicinal plant commonly used in traditional medicine to relieve pain in inflammatory processes.

Aim of the study

In the present study, the in vivo antinociceptive effect of Urtica circularis ethanolic 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: 72.2 mg/kg, i.p.) and formalin (ED50: 15.8 mg/kg, i.p.) administered intraperitoneally and also orally. Atropine diminished the activity of the extract in the acetic acid test. In this model, at dose of 10 mg/kg i.p., vitexin was the most active of the isolated compounds (inhibition of 91%), and chlorogenic acid, caffeic acid and vicenin-2 (6,8-di-C-glucosyl apigenin) produced an inhibition of 72%, 41% and 41%, respectively, whereas apigenin did not show any activity.

Conclusions

These results suggest that Urtica circularis extract produced antinociception possibly related to the presence of vitexin, chlorogenic, caffeic acid and vicenin-2. The activation of cholinergic systems seems to be involved in the mechanism of antinociception of the extract.     

Anti-nociceptive and anti-inflammatory activities of the methanolic extract of Parinari polyandra stem bark in rats and mice

The methanolic extract of the stem bark of Parinari polyandra (family Rosaceae) was investigated for possible anti-nociceptive and anti-inflammatory effects in mice and rats. Three models were used to study the extracts effects on nociception which were the acetic acid-induced abdominal constriction test, hot-plate method (both in mice) and the formalin test in rats. The anti-inflammatory effects were investigated employing the albumin-induced hind-paw oedema in rats. Results of the study revealed the extract to have significant (P<0.05) anti-nociceptive effect at a dose of 200 mg/kg p.o. in mice and rats in all the models for anti-nociception while 100 mg/kg p.o. showed significant (P<0.05) effect in the acetic acid-induced abdominal constriction test and in phase I of the formalin test. The extract also exhibited anti-inflammatory effects which were found to be significant (P<0.05) at 200 mg/kg p.o. in the rats tested. Preliminary phytochemical screening of the extract showed the presence of flavonoids, tannins, and saponin glycoside. The results suggest the extract contains pharmacologically active principles. The result is in agreement with the local application of the plant in painful and inflammatory conditions.     

Anticonvulsant, analgesic and antipyretic activities of Taxus wallichiana Zucc

Taxus wallichiana Zucc. (Himalayan Yew) is often used in northern areas of Pakistan for the treatment of pyrexia, acute pains and epilepsy. We have investigated certain pharmacological activities of the methanol leaf extract against convulsion, nociception and pyrexia induced in rodents. The aim was to justify and explore its folk uses in these pathological conditions, on scientific basis. The studies were carried out using acetic acid-induced nociception and pentylenetetrazole-induced convulsions in mice, while formalin test and yeast-induced pyrexia in rats. Significant analgesic (67.77 and 74.29%) effect was found in acetic acid-induced model at doses of 100 and 200mg/kg, i.p. respectively. Crude extract exhibited significant (P<0.05) inhibition of the formalin noxious stimulation on both early and late phases of pain by the extracts (100 and 200mg/kg doses). In case of yeast-induced pyrexia model, 200mg/kg dose showed very significant (P<0.01) inhibition while 50 and 100mg/kg dose caused a significant (P<0.05) inhibition. Plant extract has controlled the pentylenetetrazole-induced convulsions in mice. 100 and 200mg/kg i.p doses of the extract significantly (P<0.05) inhibited the mioclonus and clonus while inhibition of tonus and hind limb tonic extension (HLTE) was highly significant (P<0.01). The anticonvulsant activity of this plant has been reported for the first time throughout the whole genus. The observed pharmacological activities provide the scientific basis for the folkloric use of the plant in treating epilepsy, pyrexia and acute pain.     

Antinociceptive and anti-inflammatory effects of Thespesia populnea bark extract

The ethanolic extract of Thespesia populnea bark (TPE) was investigated for anti-inflammatory and analgesic activity at the doses (p.o.) of 100, 200 and 400mg/kg body weight. For evaluation of inflammation carrageenan-, histamine- and serotonin-induced paw edema served as acute models and formaldehyde-induced arthritis served as a chronic model in rats. The acetic acid-induced writhing response and formalin-induced paw licking time in the early and late phases of mice were used to assess analgesic activity. The higher doses of TPE (200 and 400mg/kg, p.o.) were inhibiting carrageenan, histamine and serotonin-induced paw edema as well as formaldehyde-induced arthritis successfully. In addition, TPE (200 and 400mg/kg, p.o.) significantly attenuated the writhing responses induced by an intraperitoneal injection of acetic acid and late phase of pain response induced by an subplantar injection of formalin in mice. Furthermore, our phytochemical studies indicated that the ethanolic extract of bark contains alkaloids, carbohydrates, protein, tannins, phenols, flavonoids, gums and mucilage, saponins and terpenes. From acute oral toxicity studies (OECD-423 guidelines), no mortality was observed even at highest dose of TPE (2000mg/kg, p.o.).     

Analgesic and Antiinflammatory Effects of the Tannin Fraction from Myracrodruon urundeuva Fr. All.

The present work showed a significant antinociceptive activity in the tannin fraction (TF) extracted from the bark of Myracrodruon urundeuva Fr. All. This inhibitory effect was demonstrated not only against abdominal contractions but also in the formalin test in mice. In the first case, at doses of 0.1 and 1 mg/kg, i.p. the TF caused inhibitions of the order of 39.6% and 80.8%, respectively, and in the second one, inhibitions of 47.8% and 77.2% (phase I) and 59.2% and 100% (phase II), after the administration of 5 and 10 mg/kg, i.p. The antinociceptive effect was partially reverted by naloxone. The TF presented also an antioedematogenic effect in rat paw oedema induced by carrageenan as well as dextran. In the carrageenan model, significant inhibitions were seen at 2 h (29.7% and 41.7%) and 3 h (40.5% and 44.2%), after administration of 5 and 10 mg/kg, i.p. In the dextran induced oedema, the TF (10 mg/kg, p.o.) caused inhibitions of 29.2%, 42.4% and 54.5% at 2 h, 3 h and 4 h, respectively. The TF (10 and 25 mg/kg, i.p.) significantly inhibited the inflammatory events (vesical oedema and increased vascular permeability) which occur at the onset of the haemorrhagic cystitis induced by cyclophosphamide. After subcutaneous or oral administration, the TF (5–50 mg/kg) also blocked neutrophil migration induced by direct (fMLP) as well as indirect (carrageenan) stimuli. © 1997 by John Wiley & Sons, Ltd.