Analgesic Effects of Aqueous Extracts of the Leaves of Bryophyllum pinnatum.

Abstract

Bryophyllum pinnatum. Linn (Crassulaceae) is a shrub with simple or trifoliate petiolate leaves used mainly in folk medicine to alleviate pains of various intensities and etiologies. The analgesic potency of the aqueous extract of the leaves of B. pinnatum. was investigated using animal models. Results showed that the aqueous extract of B. pinnatum. was devoid of severe toxic effects (LD₅₀ = 660.9±2.65 mg/kg body weight), increased the pain threshold in rats using the hot plate or thermal methods, inhibited or reduced phenylbenzoquinone-induced writhing or abdominal stretches in mice in a dose-dependent manner, and produced a weak or an inferior anti-inflammatory activity than aspirin. It is concluded that the aqueous extract of B. pinnatum. can demonstrate strong analgesic potency comparable in a times-and dose-dependent manner to a nonsteroidal anti-inflammatory drug.     

Analgesic and anti-inflammatory effect of aqueous extract of the stem bark of <Emphasis Type="Italic">Allanblackia gabonensis</Emphasis> (Guttiferae)

Allanblackia gabonensis (Guttiferae) is a plant used in the African traditional medicine as remedies against pain, rheumatism, inflammations. In the present work, the analgesic effect of aqueous extract has been evaluated using acetic acid, formalin, hot-plate test, tail immersion and paw-pressure test. The anti-inflammatory effect of this extract was also investigated on carrageenan, histamine or serotonin induced by paw oedema. Aqueous extract of stem bark of A. gabonensis administrated p.o. showed significant activity against paw oedema induced by carrageenan, with a maximum percentage of inhibition reaching the 74.01% at the preventive test at a dose of 200 mg/kg. A. gabonensis exhibited a significant reduction of paw oedema induced by both histamine and serotonin with a maximal inhibition of 56.94% (200 mg/kg) and 40.83% (100 mg/kg), respectively. It showed significant protective effects against chemical stimuli (acetic acid and formalin) in the mouse. Administered orally at the doses of 100–400 mg/kg, exhibited protective effect of at least 69.78% on the pain induced by acetic acid and also reduced first (67.18% at 200 mg/kg) and second (83.87% at 400 mg/kg) phase of pain-induced par formalin. It also produced a significant increase of the threshold of sensitivity to pressure and hot plate-induced pain in the rats. These results suggest a peripheral and central analgesic activities as well as an anti-inflammatory effect of the stem bark of A. gabonensis.     

Anti-inflammatory and analgesic activities of the ethanolic extracts from Zanthoxylum riedelianum (Rutaceae) leaves and stem bark

We have evaluated the anti-inflammatory and analgesic properties of the leaves (LCE) and stem bark (BCE) crude extracts of Zanthoxylum riedelianum (Rutaceae). Different fractions of the stem bark extract (hexane, BCEH; dichloromethane, BCED; ethyl acetate, BCEE; and lyophilized aqueous residual, BCEW) were also investigated. We studied the effects of the extracts and fractions using the rat paw oedema test induced by carrageenan, dextran, histamine or nystatin; the mouse abdominal constriction test; the mouse hot-plate test (only for LCE and BCE); and the mouse formalin test. Both extracts and all BCE fractions displayed anti-inflammatory activity in the carrageenan-induced oedema model, but not for dextran, histamine or nystatin. Considering the analgesic models, both extracts showed antinociceptive activity, but BCE was more active than LCE in models of central pain. All BCE fractions showed significant inhibition in the abdominal constriction test and in both phases of the formalin test. When BCED was submitted to phytochemical procedures it led to the isolation of six lignans (sesamin, methylpluviatolide, dimethylmatairesinol, piperitol-4(')-O-(gamma),(gamma)-dimethylallyl ether, kaerophyllin and hinokinin), and a triterpene (lupeol). Inhibition of cyclooxygenase and its metabolites may have been involved in the mechanism of action of this plant, considering previous studies reporting the anti-inflammatory and analgesic activity for the identified lignans, as well as anti-inflammatory activity for lupeol.     

Antinociceptive and anti-inflammatory activities of the aqueous extract of <Emphasis Type="Italic">Kaempferia galanga</Emphasis> leaves in animal models

This study was performed to determine the antinociceptive and anti-inflammatory activities of aqueous extract of Kaempferia galanga leaves using various animal models. The extract, in the doses of 30, 100, and 300 mg/kg, was prepared by soaking (1:10; w/v) the air-dried powdered leaves (40 g) in distilled water (dH₂O) for 72 h and administered subcutaneously in mice/rats 30 min prior to the tests. The extract exhibited significant (P < 0.05) antinociceptive activity when assessed using the abdominal constriction, hot-plate and formalin tests, with activity observed in all tests occurring in a dose-dependent manner. Furthermore, the antinociceptive activity of K. galanga extract was significantly (P < 0.05) reversed when prechallenged with 10 mg/kg naloxone. The extract also produced a significantly (P < 0.05) dose-dependent anti-inflammatory activity when assessed using the carrageenan-induced paw-edema test. In conclusion, this study demonstrated that K. galanga leaves possessed antinociceptive and anti-inflammatory activities and thus supports the Malay’s traditional uses of the plant for treatments of mouth ulcer, headache, sore throat, etc.     

Antinociceptive Effect of the Hydroalcoholic Extract of Bauhinia splendens Stems in Mice

The analgesic effect of the hydroalcoholic extract of the stems of Bauhinia splendens (Leguminosae) has been investigated in chemical and thermal models of nociception in mice. The hydroalcoholic extract of B. splendens, 3–60 mg kg^? intraperitoneally or 50–400 mg kg^? orally, caused dose-related, and long-lasting (up to 3 h) inhibition of acetic acid-induced abdominal constriction in mice, with ID50 values of 3.2 and 177.6 mg kg^? and maximum inhibition of 95 ± 2 and 61 ± 6%, respectively. In the formalin test, the extract given intraperitoneally (1.60 mg kg^?) or orally (50–400 mg kg^?) caused graded inhibition of both phases of formalin-induced pain, being about 5- to 6-fold more potent in attenuating the second phase of pain. The calculated mean ID50 values for the first and the second phases were 11.5 and 2.5 mg kg^?, respectively, for intraperitoneal administration and > 200 and 70 mg kg^?, respectively, for oral administration; the percentages of maximum inhibition for the first and the second phases were 68 ± 6 and 99 ± 1, respectively, for intraperitoneal administration and 37 ± 6 and 69 ± 9, respectively, for oral administration. However, at the same doses the extract did not significantly affect the oedematogenic response induced by formalin. The treatment of animals with naloxone (5 mg kg^?, i.p.) completely reversed the analgesic effect caused by morphine (5 mg kg^?, s.c), but had no effect against the antinociceptive effect of the hydroalcoholic extract of B. splendens (60 mg kg^?, i.p.) when assessed against acetic acid-induced abdominal constrictions. Furthermore, the extract, in contrast with morphine, had no analgesic effect in the hot-plate test. These data show that the hydroalcoholic extract of B. splendens has significant analgesic action when assessed against several models of pain. The mechanism underlying its analgesic effect still remains unknown, but seems to be unrelated to interaction with opioid systems.     

Analgesic,anti-inflammatory and anti-platelet activities of the methanolic extract of <Emphasis Type="Italic">Acacia modesta</Emphasis> leaves

The current study was aimed to evaluate Acacia modesta for analgesic, anti-inflammatory, and anti-platelet activities. The analgesic and anti-inflammatory effects were assessed in rodents using acetic acid and formalin-induced nociception, hot plate and carrageenan-induced rat paw oedema tests. The intraperitoneal (i.p.) administration of the methanolic extract (50 and 100 mg/kg) produced significant inhibition (P < 0.01) of the acetic acid-induced writhing in mice and suppressed formalin-induced licking response of animals in both phases of the test. In the hot plate assay the plant extract (100 mg/kg) increased pain threshold of mice. Naloxone (5 mg/kg i.p.) partially reversed the analgesic effect of the extract in formalin and hot plate tests. A. modesta (100 and 200 mg/kg i.p.) exhibited sedative effect in barbiturate-induced hypnosis test similar to that produced by diazepam (10 mg/kg i.p.). The plant extract (50–200 mg/kg i.p.) produced marked anti-inflammatory effect in carrageenan-induced rat paw oedema assay comparable to diclofenac and produced a dose-dependent (0.5–2.5 mg/mL) inhibitory effect against arachidonic acid induced platelet aggregation. These data suggest that A. modesta possesses peripheral analgesic and anti-inflammatory properties, with analgesic effects partially associated with the opioid system.     

Antinociceptive and anti-inflammatory effects of the aerial parts of Artemisia dracunculus in mice

Context: Tarragon (Artemisia dracunculus L., Asteraceae) is an ancient herb, which is widely used as a medicine, flavoring, or fragrance.

Objective: To determine the antinociceptive and anti-inflammatory effects of aerial parts of tarragon, we investigated the effects of ethanolic extract of the plant in adult male Balb/c mice.

Materials and methods: Antinociceptive activity was determined using formalin, hot-plate, and writhing tests. The effect of the ethanolic extract on acute inflammation was evaluated by xylene-induced ear edema in mice. The ethanolic extract was administered at doses of 5, 10, 50, and 100?mg/kg, i.p. The control group received saline as vehicle of ethanolic extract.

Results: Our results showed that the ethanolic extract (50 and 100?mg/kg) decreased both phases of pain in the formalin test (ED₅₀?=?109.66 and 87.13?mg/kg, respectively). In the hot-plate test, the extract (50 and 100?mg/kg) increased pain threshold during 60?min (ED₅₀?=?81.03?mg/kg). The extract (50 and 100?mg/kg) exhibited antinociceptive activity against acetic acid-induced writhing (ED₅₀?=?66.99?mg/kg). The extract (50 and 100?mg/kg) showed significant activity in the xylene ear edema test (ED₅₀?=?78.20?mg/kg). Pretreatment of the animals with naloxone decreased the analgesia induced by the extract in hot-plate and formalin tests; therefore, opioid receptors may be involved, at least partly, in the analgesic effect of tarragon extract.

Discussion and conclusion: The results suggested that tarragon have significant analgesic and anti-inflammatory effects in mice, and, therefore, further studies are required to evaluate these effects and additional potential of the plant.     

Antihypernociceptive effects of Petersianthus macrocarpus stem bark on neuropathic pain induced by chronic constriction injury in rats

Petersianthus macrocarpus (Lecythidaceae) stem bark is traditionally used in West and Central Africa for the treatment of boils and pain. The present study examined the chemical composition of the aqueous and methanolic stem bark extracts of P. macrocarpus by liquid chromatography–electrospray ionization–mass spectrometry (LC–ESI–MS) . Their antinociceptive effect was evaluated using chronic constriction injury (CCI)-induced neuropathic pain in a rat model. On the ninth day post-surgery, the pain perception (allodynia and hyperalgesia) of the animals was assessed after the administration of aqueous and methanolic extracts at the doses of 100 and 200 mg/kg. In addition, the effect of the extracts was evaluated on nitric oxide activity and on the expression of pro-inflammatory cytokines (TNF-α, IL-1β, and NF-κB). The LC–ESI–MS analysis revealed the presence of ellagic acid as the major constituent in the methanol extract. Both extracts at the employed doses (100 and 200 mg/kg), significantly (p < 0.01 and p < 0.001) reduced the spontaneous pain, tactile and cold allodynia, and mechanical hyperalgesia. The methanolic extract used at the dose of 200 mg/kg significantly reduced the nitric oxide level (p < 0.001) and the gene expression levels of NF-κB (p < 0.05) and TNF-α (p < 0.01) in the brain. These data may indicate that stem bark extracts of P. macrocarpus possess a potent anti-hypernociceptive effect on CCI neuropathic pain. The inhibition of the nitric oxide pathway as well as the reduction in NF-κB and TNF-α gene expression in the brain may at least partially contribute to this effect. The results further support the use of this plant by traditional healers in pain conditions.

     

Antinociceptive,antipyretic, and anti-inflammatory activities of <Emphasis Type="Italic">Putranjiva roxburghii</Emphasis> Wall. leaf extract in experimental animals

The effects of the ether extract from the leaves of Putranjiva roxburghii (P. roxburghii) Wall. were assessed on nociceptive responses in mice by using writhing, hot plate, and formalin tests and the antipyretic activity was determined in yeast-induced fever in rats. Anti-inflammatory activities were also investigated using carrageenin-induced paw edema in rats and croton oil-induced ear and anus edemas. The ether extract (100, 200, and 400 mg/kg, p.o.) of P. roxburghii dose-dependently produced analgesic activity in acetic acid-induced writhing in mice. The extract had no significant effect in the hot plate test in mice. At the dose of 400 mg/kg, the extract significantly suppressed the licking activity in the late phase of the formalin test in mice and decreased fever induced by yeast in rats. The extract exhibited moderate inhibitory activity of inflammation in carrageenin-induced paw edema in rats. The extract inhibited croton oil-induced ear edema in a dose-dependent manner (1.25, 2.5, and 5.0 mg/ear) in mice. The extract decreased anus edema induced by croton oil at the high dose of 800 mg/kg in rats. The results indicated that the ether extract of P. roxburghii leaves possesses analgesic, antipyretic, and anti-inflammatory activities.     

Antinociceptive effect of Lafoensia pacari A. St.-Hil. independent of anti-inflammatory activity of ellagic acid

This study was performed to determine the antinociceptive and anti-inflammatory activities of ethanolic extract of Lafoensia pacari A. St.-Hil. (PEtExt) stem bark and its fractions using various animal models such as acetic acid-induced abdominal writhing, formalin-induced pain and croton oil-induced ear edema tests. The PEtExt inhibited the acetic acid-induced abdominal writhing, reduced the pain reaction time on both phases of the formalin test and decreased the edema in a dose-dependent manner. Pre-treatment with naloxone did not reverse the antinociceptive effect. Only the ethyl acetate fraction showed antinociceptive and anti-inflammatory effects. Our results also showed that this extract contains compounds with analgesic action independent of anti-inflammatory activity.     

Mechanisms Involved in the Antinociceptive Effect in Mice of the Hydroalcoholic Extract of Siphocampylus verticillatus

The antinociception caused by the hydroalcoholic extract of Siphocampylus verticillatus (Campanulaceae) has been investigated in chemical and thermal models of nociception in mice. We have also assessed some of the mechanisms underlying the antinociceptive effect of the extract. The hydroalcoholic extract of S. verticillatus (60–1000 mg kg^?1, i.p. or p.o.) produced dose-related, significant and long-lasting (6 to 8 h) inhibition of acetic acid-induced abdominal constriction in mice, with ID50 values of 204 and ～1000 mg kg^?1, respectively. In the formalin test, the extract (100–1000 mg kg^?1), given either intraperitoneally or orally, resulted in graded inhibition of both phases of formalin-induced pain, being about 2- to 4-fold more potent in attenuating the second phase of the pain. The calculated mean ID50 (mg kg^?1) values for the earlier and the later phases were: 491 and 186 and 640 and 441, respectively. In addition, the extract (60–1000 mg kg^?1, i.p. or p.o.) caused marked and dose-related inhibition of capsaicin-induced neurogenic pain with mean ID50 values of 420 and 485 mg kg^?1, respectively. The hydroalcoholic extract, at the same doses, did not significantly affect the performance of animals in the rota-rod test, nor did it have any analgesic effect in the tail-flick or hot-plate tests. The treatment of animals with naloxone (5 mg kg^?1, s.c.) significantly reversed the analgesic effect of both morphine (5 mg kg^?1, s.c.) and the extract (300 mg kg^?1, i.p.) when assessed against acetic acid-induced abdominal constrictions. The treatment of animals with l-arginine (600 mg kg^?1, i.p.) significantly attenuated the antinociceptive effects of N^G-nitro-l-arginine (l-NOARG) (75 mg kg^?1, i.p.), of the hydroalcoholic extract (600 mg kg^?1, i.p.) or of morphine (5 mgkg^?1, s.c.), when analysed against the formalin test. In addition, adrenalectomy of animals 7 days before the tests significantly reversed the antinociception caused by the hydroalcoholic extract (300 mg kg^?1, i.p.) in the formalin-induced pain. These data show that the hydroalcoholic extract of S. verticillatus has significant and long-lasting oral antinociception when assessed against both neurogenic and inflammatory models of nociception in mice. The precise mechanism responsible for the analgesic effect of the extract still remains unclear, but a great part of this effect seems to be partly related to an opioid-like action and involvement of the l-arginine-nitric oxide pathway. Finally, the antinociception caused by the hydroalcoholic extract of S. verticillatus is modulated by adrenal hormones.     

Analgesic and anti-inflammatory effects of the methanol root extracts of some selected Nigerian medicinal plants

Context: The roots of Alafia barteri Oliver (Apocynaceae), Combretum mucronatum Schumach (Combretaceae) and Capparis thonningii Schum (Capparaceae) are used in Traditional African Medicine to alleviate painful and inflammatory conditions.

Objective: This study investigated the analgesic and anti-inflammatory effects of the methanol root extracts of Alafia barteri (MeAB), C. mucronatum (MeCM), and Capparis thonningii (MeCT).

Materials and methods: Analgesic activity of the extracts (50, 100, and 200?mg/kg, p.o. 1?h) was evaluated using acetic acid-, formalin- and hot plate-induced pain while anti-inflammatory actions (100 or 200?mg/kg) were investigated using the carrageenan- and xylene-induced edema tests.

Results: MeAB, MeCM, and MeCT (200?mg/kg) inhibited acetic acid-induced abdominal constriction by 55.07, 46.67, and 47.25%, respectively. In the formalin test, the index of pain inhibition of early and late phases was, respectively, 47.83 and 81.98% for MeAB, 56.10 and 63.81% for MeCM, and 42.84 and 63.29% for MeCT (200?mg/kg). MeAB and MeCT pretreatments significantly increased the reaction time by 46.67 and 25.53%, respectively, 120?min post-treatment in the hot-plate test. Naloxone (5?mg/kg, s.c.) pretreatment 15?min before extract administration, significantly (p?MeAB, MeCM, and MeCT showed significant anti-inflammatory activity with 60.44 and 30.39%, 63.74 and 58.08%, and 50.55 and 77.84% (200?mg/kg, 4?h), respectively, inhibition of paw and ear edema.

Discussion and conclusion: The analgesic and anti-inflammatory effects of MeAB and MeCT involve an interaction with opioid pathway and/or inhibition of chemical mediators of pain and inflammation.     

The antinociceptive and anti-inflammatory effects of Salvia officinalis leaf aqueous and butanol extracts

Context: The leaf of sage Salvia officinalis L. (Lamiaceae) is reputed in the folk medicine of Arabia, and Jordan in particular, to relieve pain associated with gastrointestinal disturbance.

Objectives: Evaluation of the antinociceptive and anti-inflammatory activities of aqueous and butanol extracts of S. officinalis leaf.

Materials and methods: The analgesic effects of the aqueous extract (10, 31.6, 100, 316, 1000?mg/kg) and butanol extract (10, 31.6, 100, 316?mg/kg) were studied using the hot-plate test for mice and the formalin-induced paw licking in rats. The effects were compared to those of morphine and the influence of naloxone on these effects was also evaluated. The same concentrations of both extracts were used to evaluate their anti-inflammatory effects using the cotton pellet granuloma and carrageenan-induced paw edema in rats.

Results: The aqueous extract (10, 31.6, 100, 316, 1000?mg/kg) and butanol extract (10, 31.6, 100, 316?mg/kg) caused analgesic effect in the hot-plate latency assay as well as in early and late phases of formalin-induced paw licking in rats. These effects were reduced by the opioid receptor antagonist, naloxone (5?mg/kg). The same range of doses of both extracts caused dose-dependent inhibition of carrageenan-induced paw edema in rats as well as inhibition of cotton pellet granuloma.

Discussion and conclusion: These observations suggest that the sage leaf aqueous and butanol extracts have analgesic and anti-inflammatory effects, confirming the traditional use of this plant for pain alleviation.     

Phytochemical analysis and antinociceptive properties of the seeds of <Emphasis Type="Italic">Garcinia achachairu</Emphasis>

In a search for new and effective analgesic substances from the Brazilian biodiversity, the present study evaluates the chemical composition and antinociceptive potential of the methanol extract and a pure compound obtained from the seeds of Garcinia achachairu Rusby (Clusiaceae). The methanolic seed extract was directly subjected to purification by column chromatography and the purification was monitored by thin-layer chromatography. The main isolated compound was identified as Guttiferone A by comparison of conventional spectroscopic data (IR, NMR-¹H and ¹³C) to the literature data which was isolated for the first time from this plant. When evaluated in the acetic acid-induced nociception model in mice, the methanolic seed extract had an ID₅₀ (Inhibitory dose) of 13.1 (11.23–14.91) mg/kg and a maximal inhibition of 72 ± 4%. In the same model, Guttiferone A had an ID₅₀ of 4.54 (3.29–6.24) mg/kg and a maximal inhibition of 73 ± 5%. The methanolic seed extract and Guttiferone A were also active in pain models induced by formalin, capsaicin, glutamate and carrageenan. These data suggest that the antinociceptive effect of Guttiferone A partly depends on its interference with the synthesis or activity of the cytokine TNF-α, the keratinocyte-derived chemokine KC, and/or PGE₂. These data support, at least in part, the use of G. achachairu in folk medicine and suggest that this plant is an important source of compounds with a suitable profile for development as new and effective medicinal agents to treat pain processes.     

Anti-inflammatory, analgesic and antipyretic activity of aqueous extract of fresh leaves of Coccinia indica

This study was aimed to evaluate both post- and pre-treatment anti-inflammatory activities of the aqueous extract of fresh leaves of Coccinia indica in rats using the carrageenan-induced paw oedema method at various dose levels. Analgesic and antipyretic properties were evaluated using tail flick model and yeast-induced hyperpyrexia, respectively. Ceiling effect of the extract was observed at 50 mg/kg in pre-treatment carrageenan test. In post-treatment studies, a dose-dependent anti-inflammatory effect was observed in the dose range of 25–300 mg/kg. The effect was equivalent to diclofenac (20 mg/kg) at 50 mg/kg but it was significantly pronounced at higher doses. Effectiveness of extract in the early phase of inflammation suggests the inhibition of histamine and serotonin release. The extract produced marked analgesic activity comparable to morphine at 300 mg/kg, which suggests the involvement of central mechanisms. A significant reduction in hyperpyrexia in rats was also produced by all doses of extract with maximum effect at 300 mg/kg comparable to paracetamol. In conclusion, this study has established the anti-inflammatory activity, analgesic and antipyretic activity of C. indica and, thus, justifies the ethnic uses of the plant.     

Antinociceptive effect in mice of a hydroalcoholic extract of Neurolaena lobata (L.) R. Br. and its organic fractions

An infusion of the aerial parts of Neurolaena lobata (L.) R. Br. (Compositae-Asteraceae) is used in Caribbean folk medicine to treat several kinds of pain. In this investigation we studied the acute oral toxicity of the hydroalcoholic extract of the plant and the antinociceptive effect of the extract and of its hexane- and chloroform-partitioned fractions, given orally, in nociception and inflammatory models in mice. No signs of toxicity were observed for oral doses up to 5000 mg kg(-1) in mice. Morphine hydrochloride (100 mg kg(-1)), dipyrone sodium (200 mg kg(-1)), the hydroalcoholic extract (1000 mg kg(-1)), and its chloroform- and hexane-partitioned fractions (100 mg kg(-1)) significantly inhibited acetic acid-induced abdominal constriction in mice (100, 95, 47, 62 and 60% inhibition, respectively when compared with the negative control). In the hot-plate test in mice, morphine hydrochloride, the chloroform- and hexane-partitioned fractions, but not the hydroalcoholic extract, resulted in a significant latency increase in all observation times. In the acetic acid-induced abdominal constriction in mice, pretreatment of the animals with naloxone significantly reversed the analgesic effect of morphine, but not that of the hydroalcoholic extract or of its hexane- and chloroform-partitioned fractions. Finally, administration of the hexane- and chloroform-partitioned fractions (100 mg kg(-1)) had a significant anti-oedematogenic effect on carrageenan-induced oedema in mice. These data show that the hydroalcoholic extract of N. lobata and, in particular, its partitioned fractions have significant analgesic properties when assessed through these pain models. Their antinociceptive effect might be the result of interference with the inflammatory process.     

Analgesic Activity of Dalbergia lanceolaria. Bark Extract in Swiss Albino Mice

Abstract

The ethanol extract of Dalbergia lanceolaria. Linn. bark was subjected to pharmacological screening using various animal models. The extract showed analgesic activity when tested in acetic acid–induced writhing, tail-flick response, and formalin-induced licking tests in Swiss albino mice. The plant extract, at doses of 100, 200, and 400 mg/kg body weight, showed significant central as well as peripheral analgesic activity by oral route. Therefore, the current study indicates that the ethanol extract of Dalbergia lanceolaria. bark has significant central and peripheral analgesic activity.     

Analgesic activity of Gleditsia triacanthos methanolic fruit extract and its saponin-containing fraction

Context: Gleditsia triacanthos L. (Leguminosae) pods are used in folk medicine for pain relief as anodyne and narcotic.

Objective: The objective of this study is to evaluate analgesic activity of Gleditsia triacanthos methanolic fruit extract (MEGT) and its saponin-containing fraction (SFGT).

Materials and methods: Peripheral analgesic activity was assessed using the acetic acid-induced writhing model in mice at doses of 140, 280, and 560?mg/kg and formalin test in rats at 100, 200, and 400?mg/kg doses. Central analgesic activity was evaluated using the hotplate method in rats (100, 200, and 400?mg/kg).

Results: In the writhing test, six mice groups treated with MEGT and SFGT found ED₅₀ values 268.2 and 161.2?mg/kg, respectively, displayed a significant decrease in writhing count compared with the group treated with standard drug indomethacin (14?mg/kg). SFGT (280 and 560?mg/kg) showed 64.94 and 70.78% protection, respectively, which are more than double % protection caused by indomethacin (31.82%). In the formalin test, MEGT and SFGT (ED₅₀ values 287.6 and 283.4?mg/kg for phase I as well as 295.1 and 290.4?mg/kg for phase II, respectively) at 400?mg/kg showed significant % inhibition in both phase I (18.86 and 52.57%) and phase II (39.36 and 44.29%) with reference to 10?mg/kg indomethacin (56.0 and 32.29%). MEGT and SFGT caused significant delay in responses in hotplate model (ED₅₀ values 155.4 and 200.6?mg/kg, respectively) compared with that of 10?mg/kg indomethacin at 30, 60, and 120?min.

Discussion and conclusion: Central and peripheral analgesic activities induced by Gleditsia triacanthos fruits might account for its uses in folk medicine.     

Some Effects of Cassia italica on the Central Nervous System in Mice

This work examines some effects of the crude ethanolic extract of the medicinal plant Cassia italica, given at single oral doses of 0.25, 0.5 or 1 g kg^?1, on the central nervous system in mice. Several models of nociception have been used to examine the analgesic effect of the extract. HPLC fingerprinting of the extract was performed to ensure uniformity of the extract material used. In treated mice, the extract caused dose-related inhibition of acetic acid-induced abdominal constriction, and in the formalin test of antinociception the extract reduced formalin-induced pain in the second (late) but not in the first (early) phase of the pain. Treatment with the extract at doses of 0.5 and 1 g kg^?1 significantly increased the reaction time in the hot-plate and warm-water tail-flick tests. Naloxone was ineffective in antagonizing the analgesic effect of C. italica on tail-flick and abdominal constriction tests, possibly indicating that the effect occurs via non-opiate pathways. The C. italica extract caused slight dose-related impairment of motor control which was significant only at a dose of 1 g kg^?1. Treatment at the three doses used did not affect the rectal temperature of normothermic mice, but was effective in significantly reducing the rectal temperature of hyperthermic rats, 0.5 and 1 h (but not 6 h) after administration of the extract at doses of 0.5 and 1 g kg^?1. The extract also produced progressive diminution in the ambulatory and total activity of treated mice for up to 2 h after administration. It is concluded that the crude ethanolic extract of C. italica has CNS depressant properties, manifested as antinociception and sedation.     

Antinociceptive and anti-inflammatory activities of Tabernaemontana catharinensis

In this work we describe the analgesic, anti-inflammatory and toxic activities as well as the phytochemical profile of the ethanol extract from Tabernaemontana catharinensis A. DC. (Apocynaceae) stem bark. Analgesic evaluation was carried out against chemical and thermal stimuli. Anti-inflammatory activity was investigated on carrageenan-induced edema in rats and toxicological studies (LD₅₀) were conducted in mice. Phytochemical analyses were performed by standardized methodology. In an analgesic assay, acetic acid-induced writhings were significantly inhibited by extract doses of 37.5?mg/kg (40.97%), 75?mg/kg (77.70%) and 150?mg/kg (88.98%). A central analgesia was also observed using T. catharinensis extract at all doses tested, particularly noticed at 60 and 90?min following administration. The extract significantly reduced edema development by 30.35% (37.5?mg/kg), 34.46% (75?mg/kg), and 56.42% (150?mg/kg) when assessed 180?min following carrageenan intraplantar injection, demonstrating an effective anti-inflammatory action. The LD₅₀ value was 2200?mg/kg. Phytochemical analyses of ethanol extract from Tabernaemontana catharinensis stem bark showed the presence of alkaloids and terpenoids, which may be responsible for the observed pharmacological activities described in this work.