In vitro immunomodulatory activity and in vivo anti-inflammatory and analgesic potential with gastroprotective effect of the Mediterranean red alga Laurencia obtusa

Context: Red algae have been recognized as a rich natural source of compounds possessing interesting biological and pharmacological activities.

Objective: This work investigates anti-inflammatory, analgesic and gastroprotective activities of MeOH/CH₂Cl₂ crude extract and its fractions F1 (50% MeOH) and F2 (80% MeOH) from the whole alga plant Laurencia obtusa Hudson (Rhodomelaceae).

Materials and methods: Anti-inflammatory activity was evaluated in vitro using cytometric bead array (CBA) technology to follow up the secretion of tumour necrosis factor alpha (TNF-α) in lipopolysaccharide activated THP-1 monocytic cells at doses of 10–250?μg/mL and in vivo using carrageenan-induced paw oedema in Wistar rats at doses of 25, 50, 100 and 200?mg/kg. Crude extract and fractions were tested at the doses of 25, 50, 100 and 200?mg/kg for peripheral and central analgesic activity by acetic acid-induced writhing test and hot-plate method, respectively, in Swiss albino mice. Gastroprotective activity was evaluated using HCl/ethanol-induced gastric ulcer test in rats at doses of 25, 50, 100 and 200?mg/kg.

Results: Crude extract, F1 and F2 showed an interesting inhibition of TNF-α secretion with IC₅₀ values of 25, 52 and 24?μg/mL, respectively, and a significant anti-inflammatory activity in vivo (p?< 0.01), 3?h after carrageenan injection, the oedema inhibition was 55.37%, 52.18% and 62.86%, respectively, at the dose of 100?mg/kg. Furthermore, they showed a significant peripheral analgesic activity with 53.79%, 55.92% and 57.37% (p?< 0.01) of writhing inhibition, respectively. However, no significant activity was found in the hot-plate test. An interesting gastroprotective effect was observed with crude extract and its fractions F1 and F2 with a gastric ulcer inhibition of 65.48%, 77.42% and 81.29%, respectively, at the dose of 50?mg/kg.

Discussion and conclusion: These results suggest that L. obtusa might be used as a potential source of natural anti-inflammatory and analgesic agents with gastroprotective effect.     

Anti-inflammatory,free radical scavenging and alpha-glucosidase inhibitory activities of Hamelia patens and its chemical constituents

Context Hamelia patens Jacq. (Rubiaceae) is traditionally used to treat wounds, inflammation and diabetes. However, there is still a lack of scientific evidence to support these applications.

Objective The objective of this study is to evaluate the anti-inflammatory, antioxidant and antidiabetic activities of Hamelia patens, and identify its bioactive compounds.

Materials and methods Four extracts were obtained by maceration and liquid–liquid extraction: HEX, DCM–EtOAc, MeOH–EtOAc and MeOH–Aq. The anti-inflammatory effect was evaluated orally on rat paw carrageenan-induced oedema over 6?h (50, 200 and 500?mg/kg), and topically in mouse ear oedema induced by 12-tetradecanoylphorbol-13-acetate (TPA) after 4?h (0.5 and 1?mg/ear). We also evaluated myeloperoxidase levels in ear tissue, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging ability, and in vitro α-glucosidase inhibition. The chemical compounds were separated by column chromatography and identified by spectroscopic analysis.

Results We found that the oral administration of the HEX extract at 500 and 200?mg/kg significantly decreased the carrageenan-induced inflammation after 1 and 3?h, respectively. The MeOH–EtOAc extract significantly inhibited myeloperoxidase activity (83.5%), followed by the DCM–EtOAc extract (76%), β-sitosterol/stigmasterol (72.7%) and the HEX extract (55%), which significantly decreased oedema induced by TPA at both doses, giving a similar effect to indomethacin. We also found that the MeOH–EtOAc, MeOH–Aq and DCM–EtOAc extracts showed good DPPH scavenging activity (IC₅₀ values of 18.6, 93.9 and 158.2?μg/mL, respectively). The HEX extract showed the lowest α-glucosidase inhibition (an IC₅₀ value of 26.07?μg/mL), followed by the MeOH–EtOAc extract (an IC₅₀ value of 30.18?μg/mL), β-sitosterol/stigmasterol (IC₅₀ 34.6?μg/mL) and compound A ((6E,10E,14E,18E)-2,6,10,14,18,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene, an IC₅₀ value of 114.6?μg/mL), which were isolated for the first time from Hamelia patens.

Discussion and conclusion Hamelia patens possesses anti-inflammatory, antioxidant and α-glucosidase inhibitory activities, which support its traditional use. These effects can be attributed to the identified compounds.     

Analgesic and anti-inflammatory activities of total extract and individual fractions of Chinese medicinal ants Polyrhachis lamellidens

The ethanol extract of Chinese medicinal ants Polyrhachis lamelliden was evaluated for its analgesic and anti-inflammatory activities in mice. It was shown that the extract significantly inhibited acetic acid-induced writhing response and increased hot-plate pain threshold of mice at doses of 1.5 and 3.0 g crude drug/kg. Meanwhile, the extract significantly inhibited the increase in vascular permeability induced by acetic acid and in ear edema induced by xylene in mice. However, it had no obvious effect on leukocyte migration induced by carboxymethylcellulose sodium (CMC-Na). The ethanol extract suspended in water was partitioned with diethyl ether, ethyl acetate and n-butanol successively to yield four fractions including water fraction. Among these fractions, diethyl ether and ethyl acetate fractions were found to increase hot-plate pain threshold and to inhibit acetic acid-induced writhing response in mice. Water fractions markedly inhibited acetic acid-induced writhing response and reduced the dye leakage to the peritoneal cavity induced by acetic acid and ear edema induced by xylene. These results suggest that P. lamellidens presents remarkable analgesic and anti-inflammatory activity, which supported the traditional use of the medicinal ants in the treatment of various diseases associated with inflammation. The diethyl ether fraction has greater contribution to the overall analgesic activity, whereas the water fraction showed the greatest anti-inflammatory and peripheral analgesic activities.     

Anti-inflammatory action of phenolic compounds fromGastrodia elata root

Previous screening of the pharmacological action of Gastrodia elata (GE) root (Orchidaceae) showed that methanol (MeOH) extracts have significant anti-inflammatory properties. The anti-inflammatory agents of GE, however, remain unclear. In this experiment, MeOH extracts of GE were fractionated with organic solvents for the anti-inflammatory activity-guided separation of GE. Eight phenolic compounds from the ether (EtOEt) and ethyl acetate (EtOAc) fractions were isolated by column chromatography: 4-hydroxybenzaldehyde (I), 4-hydroxybenzyl alcohol (II), benzyl alcohol (III), bis-(4-hydroxyphenyl) methane (IV), 4(4'-hydroxybenzyloxy)benzyl methylether (V), 4-hydroxy-3-methoxybenzyl alcohol (VI), 4-hydroxy-3-methoxybenzaldehyde (VII), and 4-hydroxy-3-methoxybenzoic acid (VIII). To investigate the anti-inflammatory and anti-oxidant activity of these compounds, their effects on carrageenan-induced paw edema, arachidonic acid (AA)-induced ear edema and analgesic activity in acetic acid (HAc)-induced writhing response were carried out in vivo; cyclooxygenase (COX) activity, reactive oxygen species (ROS) generation in rat basophilic leukemia (RBL 2H3) cells and 1,1-diphenyl-2-picryl-hydroazyl (DPPH) scavenging activity were determined in vitro. These phenolic compounds not only had anti-inflammatory and analgesic properties in vivo, but also inhibited COX activity and silica-induced ROS generation in a dose-dependent manner. Among these phenolic compounds, compound VII was the most potent anti-inflammatory and analgesic. Compound VII significantly inhibited silica-induced ROS generation and compound VI significantly increased DPPH radical scavenging activity. Compounds I, II and III significantly inhibited the activity of COX-I and II. These results indicate that phenolic compounds of GE are anti-inflammatory, which may be related to inhibition of COX activity and to anti-oxidant activity. Consideration of the structure-activity relationship of the phenolic derivatives from GE on the anti-inflammatory action revealed that both C-4 hydroxy and C-3 methoxy radicals of benzyl aldehyde play an important role in anti-inflammatory activities.     

Anti-inflammatory and antiallergic activity in vivo of lipophilic Isatis tinctoria extracts and tryptanthrin

The effects of a supercritical CO2 (SFE) extract, a dichloromethane (DCM) extract from Isatis tinctoria leaf and the alkaloidal constituent tryptanthrin were studied in acute and subchronic experimental models of inflammation. The SFE and DCM extracts showed anti-inflammatory activity in the carrageenan-induced acute mouse paw oedema (ED50 values of 78 mg/kg and 165 mg/kg P. O., respectively) and in the acute tetradecanoylphorbol acetate (TPA)-induced mouse ear oedema in oral (62% and 32% oedema reduction at 100 and 125 mg/kg, respectively) and topical application (37% and 33% reduction of oedema at 0.5 mg/ear). In contrast, tryptanthrin showed no significant anti-inflammatory effect. The DCM extract inhibited oedema formation and neutrophil infiltration in subchronic inflammation in mice induced by repeated application of TPA. The extract showed activity after oral and topical administration by reducing the various parameters of the inflammatory response. The DCM extract (1 mg/ear) inhibited the delayed-type hypersensitivity (DTH) reaction induced by application of dinitrofluorobenzene (DNFB) after topical application. The response during the induction phase (24 h) was decreased by 48%, and the inflammatory phase (48 to 96 h) was reduced by 53 to 56%. The extract had no effect in this model when administered orally. The DCM extract (200 mg/kg P. O.) inhibited the acetic acid-induced writhing by 49%.     

Anti-inflammatory Properties of Entada abyssinica. Leaves

Abstract

The effects of the defatted methanol extract of Entada abyssinica. Steud. ex A. Rich leaves on some models of inflammation were investigated. The analgesic property of the plant extract was also tested on acetic acid–induced writhing, as well as formalin-induced paw licking, in mice. The antipyretic effect was evaluated using yeast-induced hyperpyrexia in mice. At doses of 50–200 mg/kg, the extract produced significant (p < 0.05) inhibition of leukocyte migration after intraperitoneal injection of carrageenan in rats. A topical anti-inflammatory effect was produced by 20 mg/ear of the extract, as demonstrated by inhibition of croton oil–induced ear edema in mice. The analgesic property of the plant extract was observed by inhibition of acetic acid–induced writhing and paw licking induced by formalin in mice. The extract, however, exhibited no antipyretic activity. This study further established the anti-inflammatory activity of E. abyssinica., in addition to its analgesic effect.     

Scavenging of reactive oxygen species by Eriobotrya japonica seed extract

We have clarified that Eriobotrya japonica seed extract has strong antioxidative activity, and is effective for the prevention and treatment of various diseases, such as hepatopathy and nephropathy. In this study, to investigate the influences of components of Eriobotrya japonica seed extract on its antioxidative activity, extracts were prepared using various solvents (n-hexane (Hex), ethyl acetate (EtOAc), n-butanol (n-BuOH), methanol (MeOH) and H2O) and the antioxidative activity of the solvent fractions and components was evaluated based on the scavenging of various radicals (DPPH and O2(-)) measured by the ESR method and the inhibition of Fe3+-ADP induced NADPH dependent lipid peroxidation in rat liver microsomes. The radical scavenging activities and inhibitory activities on lipid peroxidation differed among the solvent fractions and components. In the n-BuOH, MeOH and H2O fractions, radical scavenging activity and inhibitory activity on lipid peroxidation were high. In addition, these fractions contained abundant polyphenols, and the radical scavenging activity increased with the polyphenol content. In the low-polar Hex and EtOAc fractions, the radical scavenging activity was low, but the lipid peroxidation inhibition activity was high. These fractions contained beta-sitosterol, and the inhibitory activity on lipid peroxidation was high. Based on these findings, the antioxidative activity of Eriobotrya japonica seed extract may be derived from many components involved in a complex mechanism, resulting in high activity.     

多枝雾水葛不同提取部位的抗炎镇痛作用研究

目的 研究多枝雾水葛不同提取物的抗炎镇痛作用.方法 采用二甲苯致小鼠耳肿胀、醋酸致小鼠扭体反应和小鼠热板法观察多枝雾水葛灌胃、外搽使用以及不同提取部位的抗炎、镇痛作用.结果 多枝雾水葛外搽使用的抗炎镇痛效果不明显,灌胃给药具有较强的抗炎镇痛作用,能显著减少醋酸所致的小鼠扭体次数和抑制二甲苯所致的小鼠耳廓肿胀,且其水提物比醇提物的作用更强.对多枝雾水葛水提取物的活性部位研究表明,多枝雾水葛的氯仿部位和水部位都具有较好的镇痛效果,抗炎的有效部位则是氯仿部位和正丁醇部位.结论 多枝雾水葛水提取物灌胃给药具有抗炎镇痛作用,其有效部位是氯仿部位、正丁醇部位和水提取部位.     

The analgesic,anti-inflammatory and calcium antagonist potential of<Emphasis Type="Italic">Tanacetum artemisioides</Emphasis>

Several species of the genus Tanacetum are traditionally used in a variety of health conditions including pain, inflammation, respiratory and gastrointestinal disorders. In the current investigation, we evaluated the plant extract of T. artemisioides and some of its pure compounds (flavonoids) for analgesic, anti-inflammatory and calcium antagonist effects in various in-vivo and in vitro studies. Using the actetic acid induced writhing test, intraperitoneal (i.p) administration of the plant extract (25-50 mg/kg) and its flavonoid compounds TA-1 and TA-2 (1-5 mg/kg ) exhibited significant analgesic actvity. The maximum analgesic effect observed with the crude extract of the plant was 71% at 50 mg/kg, while that of compounds TA-1 and TA-2 (5 mg/kg i.p) was 75 and 47%, respectively. The plant extract and its pure compounds caused inhbition of formalin induced paw licking in mice predominatly in the second phase of the test. Diclofenac sodium, a standard reference compound, showed a simlar effect in these chemical induced pain models. In the carrgeenan induced rat paw edema assay, the plant extract (50-200 mg/kg i.p) demonstrated significant (P< 0.01) anti-inflammatory activity which was comparable to that obtained with diclofenac sodium and indomethacin. In isolated rabbit jejunum preprations the plant extract showed an atropine sensitive dose-dependent (0.10-1.0 mg/mL) spasmogenic activity followed by a spasmolytic effect at the next higher doses (3-5 mg/mL). The crude extract of the plant also inhibited the high K+-induced contractions, indicating a calcium channel blocking (CCB) activity, which was further confirmed when the plant extract caused a rightward shift in the Ca++ concentration response curves in the isolated rabbit jejunum preparations, similar to that seen with verapamil. The flavonoid compounds isolated from the plant were devoid of any activity in the isolated tissue preparations. These results indicate that the plant extract of T. artemisioides possesses analgesic, anti-inflammatory and CCB activities. The flavonoid compounds of the plant may have a role in its observed analgesic and antiinflammatory activities, while the CCB activity of the plant may be attributed to some other chemical constituents present. Moreover the findings support the traditional reputation of the genus Tanacetum for its therapeutic benefits in pain and inflammatory conditions.     

Antinociceptive and anti-inflammatory effects of the ethyl acetate stem bark extract of Bridelia scleroneura (Euphorbiaceae)

Bridelia scleroneura is a member of the Euphorbiaceae family. In folk medicine in Cameroon, the stem bark of this plant is used for relieving abdominal pain, contortion, arthritis and inflammation. In this study, the antinociceptive and anti-inflammatory activities of the ethyl acetate stem bark extract have been evaluated. The putative analgesic effect of the plant extract was examined in abdominal constriction, hot plate, formalin and on pain using tail immersion mouse models and in carrageenan-induced paw edema in rats. The extract (150–600 mg/kg) exhibited a dose-dependent analgesic effect (46.27–78.97%) in acetic acid-induced abdominal constriction in mice. B. scleroneura extract increased the pain latency of nociceptive response to thermal stimuli at the higher dose of 600 mg/kg. B. scleroneuna induced significant dose-dependent reduction of the nociception in both early and late phases of the formalin test. The extract at the dose of 300 mg/kg, increased significantly, by 63.70% and 52.01% the tail-immersion latency time, 1 and 2 h post-dosing. In the carrageenan test, B. scleroneura (150–600 mg/kg, p.o) had dose-dependent and significant effects at different time intervals. This behaviour was similar to indometacin (10 mg/kg) used as a standard drug. These results show that the ethyl acetate stem bark extract of B. scleroneura possesses peripheral and central analgesic properties as well as anti-inflammatory activity against acute inflammation processes, in support of the folk medicinal use of the plant.     

Antioxidant, anti-inflammatory and analgesic potential of the Citrus decumana L. peel extract

The present study was designed to investigate the antioxidant, anti-inflammatory and analgesic potential of Citrus decumana peel extract. Antioxidant activity of Citrus decumana peel extract in four solvent systems was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH^·) and hydrogen peroxide (H₂O₂) radical scavenging methods. Ethyl acetate peel extract of Citrus decumana (EtCD) was studied for its anti-inflammatory and analgesic activities at a dose level of 100, 200 and 300 mg/kg. Anti-inflammatory activity was performed using carrageenan-induced paw edema in rats. Analgesic activity was evaluated for its central and peripheral pharmacological actions in mice. EtCD showed significant antioxidant activity in a dose-dependent manner when compared with ascorbic acid. EtCD at the dose of 300 mg/kg produced significant decrease in paw volume and pain when compared with reference drug diclofenac and morphine, respectively. The Citrus decumana peel extract may be useful as a natural antioxidant in the treatment of inflammation and pain.     

Analgesic and Anti-Inflammatory Effects of Alangium salvifolium

The methanol extract of Alangium salvifolium plant roots has been studied for analgesic and anti-inflammatory activities in animal models. The methanol extract produced significant dose-dependent inhibition of carrageenan-induced rat paw edema. The extract also showed marked analgesic activity. Acute toxicity studies with mice showed no mortality up to 1 g/kg body weight when administered intraperitoneally.     

Phytochemical and analgesic activity of extract, fractions and a 19-hydroxyursane-type triterpenoid obtained from Rubus rosaefolius (Rosaceae)

The Rubus species has been used in folk medicine to treat several ailments, including infectious and dolorous diseases. In this work we evaluate the phytochemical and analgesic activity of hydroalcoholic extract (HE), some fractions (hexane, dichloromethane, ethyl acetate and butanolic), as well as a pure compound denoted as 28-methoxytormentic acid (1) obtained from aerial parts of R. rosaefolius. The compounds were isolated and identified by chromatographic and spectroscopic analysis. The antinociceptive action was evaluated by two well know models of pain in mice: writhing and formalin induced-pain. The results showed that the HE, fractions and compound (1), exhibits potent and dose-related analgesic activity when evaluated in both models of pain. Compound (1), which seems to be the main active principle, showed promising analgesic effects, being several times more potent than aspirin and paracetamol, two well-known analgesic and antiinflammatory drugs used as reference. In the writhing test, it showed an ID(50) of 5.10 (3.64-7.14) mg kg(-1) and maximum inhibition (MI) of 64.22%. When analyzed by formalin induced-pain test, this compound showed ID(50) values of 9.98 (8.08-12.31) and 6.31 (5.07-7.98) mg kg(-1) and MI of 59.37 and 90.37% for the first and second phases, respectively. The results justify, at least partially the popular use of this plant for the treatment of dolorous processes, suggesting that 1 is one of the active principles of this plant.     

Analgesic and anti-inflammatory activity of β-sitosterol isolated from Nyctanthes arbortristis leaves

Nyctanthes arbortristis Linn. (Oleaceae) is one of the well-known Indian medicinal plant. Various extracts of leaves of the plant were screened for analgesic activity by hot plate test and acetic acid-induced writhings and anti-inflammatory activity by carrageenan-induced hind paw edema method at the dose of 50?mg/kg, i.p. Petroleum ether extract was found to be most active and hence subjected to activity-guided fractionation. Results showed that β-sitosterol (5, 10 and 20?mg/kg, i.p.) was responsible for the significant and dose-dependent activity comparable with the standard extract. β-Sitosterol from N. arbortristis leaves might be responsible for analgesic and anti-inflammatory activity.     

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.     

Anti-inflammatory and antinociceptive effect of Pachygone ovata leaves

Context: Pachygone ovata (Poir.) Miers ex Hook. F. et Thoms (Menispermaceae) is a rich source of bioactive bisbenzylisoquinoline and aporphine alkaloids.

Objective: This study investigates the in vitro and in vivo anti-inflammatory and antinociceptive potential of Pachygone ovata leaves.

Materials and methods: Lipoxygenase (LOX) assay for anti-inflammatory activity was conducted using MeOH, EA, H and Aq extracts; followed by alkaloid isolation. The anti-inflammatory potential was determined using carrageenan-induced paw oedema and formalin tests for evaluation of Pachygone ovata analgesic effect. Different doses (100, 300 and 400?μg/kg) were administered orally to Wistar rats for a period of one week, once daily.

Results: MeOH and EA extract efficiently inhibited LOX (IC₅₀ 1.43 and 2.15?μg/mL, respectively). MeOH extract had better inhibiting capacity (57%) than indomethacin (51%) in carrageenan induced rats. MeOH extract (300?μg/kg) significantly reduced the increased levels of nitric oxide (8?±?0.57 M), total leukocyte count (4.5?±?0.05 cells 10³/cells) and C-reactive protein (55?±?0.45?mg/mL). There was a decrease in various serum biochemical markers (ALT, AST). Histopathological studies revealed reduction in oedema and decreased cellular infiltration on supplementation with MeOH extract. Furthermore, MeOH extract (300?μg/kg) and alkaloid fraction (400?μg/kg) effected both phases (neurogenic and inflammatory) of formalin injected models.

Discussion and conclusion: Inflammatory mediators play a key role in inflammation; therefore, keeping it in control is of utmost importance. The usefulness of Pachygone ovata leaves on pain and inflammation has been described, probably due to its effect on inflammatory mediators and high alkaloid content.     

鸭跖草抗炎镇痛有效部位实验研究

目的：研究鸭跖草不同提取物的抗炎镇痛作用。方法取鸭跖草的水提取物和乙醇提取物,采用二甲苯致小鼠耳肿胀、小鼠棉球肉芽肿胀为抗炎筛选方法;以冰醋酸扭体法、热板法为镇痛筛选方法。结果鸭跖草乙醇提取物和水提起物可减轻二苯致小鼠耳廓肿胀程度,减小小鼠棉球肉芽肿胀程度,减少醋酸致小鼠扭体次数,乙醇提物能延长小鼠舔足时间,乙醇提取物作用强于水提取物,其镇痛抗炎效果均表现出明显的剂量依赖关系。结论中药鸭跖草乙醇提取物具有明显的镇痛抗炎作用。     

Rhododendrin,an analgesic/anti-inflammatory arylbutanoid glycoside,from the leaves of <Emphasis Type="Italic">Rhododendron aureum</Emphasis>

To identify an analgesic/anti-inflammatory component from the leaves of Rhododendron aureum (Ericaceae), phytochemical isolation and pharmacological assays (writhing assays and vascular permeability assay for analgesic action in mice; carrageenan-induced paw edemaand TPA-induced ear edema assays of anti-inflammatory action in rats) were performed. Four compounds were isolated from the active fraction (BuOH fraction) by silica gel column chromatography and identified as (−)-rhododendrol, (−)-rhododendrin, avicularin and hyperoside by spectroscopic methods. Rhododendrin, the main compound of the BuOH fraction, exhibited significant analgesic actions in mice and anti-inflammatory actions in rats. This compound accounted for 3.1% of the MeOH extract and 0.48% of dried leaves, respectively, on HPLC analysis. These results suggest that rhododendrin is the major biologically active substance in the leaves of R. aureum with analgesic/anti-inflammatory activity.     

Antinociceptive effects of the extracts of <Emphasis Type="Italic">Xylopia parviflora</Emphasis> bark and its alkaloidal components in experimental animals

In the present study, we attempted to elucidate the antinociceptive activity of Xylopia parviflora bark using the acetic acid-induced writhing test, hot plate test, and formalin test in mice. The MeOH extract (100 and 200 mg/kg, administered intraperitoneally (i.p.)) had an antinociceptive effect demonstrated by its inhibitory effects on writhing number induced by acetic acid. Three alkaloidal fractions exhibited significant antinociceptive effects in three animal models; the chloroform-soluble fraction, including secondary and tertiary alkaloids, exhibited the strongest effect. This result supported its use in folk medicine as an analgesic agent. We tested the main alkaloids of these fractions for their antinociceptive effects to clarify the active components. (+)-Corytuberine (6.3 and 12.5 mg/kg, i.p.) showed very strong activity, had a significant antinociceptive effect in the acetic acid-induced writhing test (with 49.4 and 98.9% reduction of writhes), in the hot plate test, and in the formalin test (with 55.4 and 90.6% inhibition during the first phase, and 73.9 and 99.9% during the second phase, respectively). (+)-Glaucine (12.5 and 25 mg/kg, i.p.) showed strong activity in three animal models, too. The activity of these compounds was also observed following oral administration in the acetic acid-induced writhing test.     

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.