Evaluation of the disease modifying activity of Colchicum luteum Baker in experimental arthritis

Ethnopharmacological relevance

Colchicum luteum (CL) has been traditionally used in the Unani system of medicine as a chief ingredient of many polyherbal formulations for the treatment of joint pain and rheumatoid arthritis (RA).

Aim of the study

To evaluate the antiarthritic activity of CL hydroalcoholic extract (CLHE) in formaldehyde and complete Freund's adjuvant (CFA) induced arthritis.

Materials and methods

Arthritis was induced by administration of either formaldehyde (2% v/v) or CFA into the subplantar surface of the hind paw of the animal. Joint swelling was measured on days 8, 9 and 10 in formaldehyde induced arthritis and days 3, 7, 14 and 21 in CFA induced arthritis. In order to evaluate the effect of CLHE on disease progression, serum TNF-α level and synovial expression of proinflammatory mediators (TNF-R1, IL-6 and IL-1β) was determined in CFA induced arthritis.

Results

CLHE produced a significant and dose dependent inhibition of joint swelling during the entire duration of the study in both, formaldehyde and CFA induced arthritis. Serum TNF-α level was also reduced significantly in a dose dependent manner in all the CLHE treated groups. The expression of proinflammatory mediators (TNF-R1, IL-6 and IL-1β) was also found to be less in the CLHE treated group as compared to control.

Conclusion

We believe that the antiarthritic activity of CLHE was due to its modulatory effect on the expression of proinflammatory cytokine in the synovium. Our results contribute towards validation of the traditional use of CL in the treatment of RA and other inflammatory joint disorders.     

Xanthine oxidase inhibitory properties of Czech medicinal plants

Aim of the study

To investigate in vitro xanthine oxidase inhibitory properties of plants traditionally used in Czech Republic and Central-East Europe region for gout, arthritis or rheumatism treatment.

Materials and methods

Methylene chloride-methanolic and two ethanolic extracts of 27 plant species were screened for in vitro xanthine oxidase inhibitory activity using a spectrophotometric method.

Results

Around 50% of the species exhibited some degree of xanthine oxidase inhibitory properties at 200 μg/mL, showing a moderate correlation (r = 0.59) with total phenol content. The most active were methylene chloride-methanolic extracts of Populus nigra and Betula pendula, with IC₅₀ of 8.3 and 25.9 μg/mL, respectively, followed by 80% ethanolic extract of Caryophyllus aromaticus and Hypericum perforatum, both under 50 μg/mL.

Conclusions

Populus nigra and Betula pendula were identified as species with the highest xanthine oxidase inhibitory potential in our study. This correlates with the ethnobotanical data on their use in Central European folklore and provides the basis for further investigation on these plants.     

Hypoglycaemic activity and molecular mechanisms of Caesalpinia ferrea Martius bark extract on streptozotocin-induced diabetes in Wistar rats

Ethnopharmacological relevance

The tea from the stem bark of Caesalpinia ferrea Martius (Leguminosae) has been popularly used in the treatment of diabetes in Brazil.

Aim of the study

To investigate the hypoglycaemic properties and to elucidate the mechanisms by which the aqueous extract of the stem bark of Caesalpinia ferrea reduces blood glucose levels in streptozotocin-induced diabetic rats via the enzymatic pathways of protein kinase B (PKB/Akt), AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC).

Materials and methods

The aqueous extract of the stem bark of Caesalpinia ferrea (300 and 450 mg/kg/day), vehicle and metformin (500 mg/kg/day) were administered orally to STZ-diabetic rats (n = 7/group) for 4 weeks. Changes in body weight, food and water intake, fasting glucose levels and oral glucose tolerance were evaluated. Phosphorylation (P) and the expression of Akt, AMPK and ACC in the liver and skeletal muscle were determined using Western blot.

Results

The aqueous extract of the stem bark of Caesalpinia ferrea reduced blood glucose levels and improved the metabolic state of the animals. P-Akt was increased in the liver and skeletal muscle of the treated animals, P-AMPK was reduced only in the skeletal muscle of these animals and P-ACC was reduced in both when compared with untreated rats.

Conclusion

The results indicate that the aqueous extract of the stem bark of Caesalpinia ferrea has hypoglycaemic properties and possibly acts to regulate glucose uptake in liver and muscles by way of Akt activation, restoring the intracellular energy balance confirmed by inhibition of AMPK activation.     

Anticonvulsant activity of aqueous root extract of Ficus religiosa

Ethnopharmacological relevance

Ficus religiosa Linn is frequently used for the treatment of nervous disorders among Pawara tribe of the Satpuda range, India.

Aim of the study

This study aimed to investigate the anticonvulsant activity of the aqueous aerial root extract of Ficus religiosa in chemoconvulsant-induced seizures in mice.

Materials and methods

The anticonvulsant activity of the extract (25, 50 and 100 mg/kg, p.o.) was investigated in strychnine-, pentylenetetrazole-, picrotoxin- and isoniazid-induced seizures in mice. Rat ileum and fundus strip preparations were used to study the effect of the extract on acetylcholine (Ach)- and serotonin (5-HT)-induced contractions, respectively.

Results

The extract showed no toxicity and protected the animals in the strychnine and pentylenetetrazole tests in a dose-dependent manner. Its effect in the picrotoxin and isoniazid tests, however, was less potent. The extract also exhibited dose-dependent potentiation of Ach in rat ileum but failed to potentiate the effect of 5-HT in rat fundus strip preparation.

Conclusions

The results suggest that an orally administered aqueous root extract of Ficus religiosa has dose-dependent and potent anticonvulsant activities against strychnine- and pentylenetetrazole-induced seizures. The observed activities may be ascribed to the appreciable content of zinc and magnesium in the extract.     

Anti-inflammatory activity of Terminalia paniculata bark extract against acute and chronic inflammation in rats

Ethnopharmacological relevance

Terminalia paniculata Roxb. (Family-Combretaceae) is a wild tree commonly used in traditional ayurvedic medicine for the treatment of inflammation of parotid glands and in menstrual disorders.

Aim of the study

To explore the folk use of Terminalia paniculata on pharmacological grounds to evaluate the scientific basis of anti-inflammatory activity.

Materials and methods

The anti-inflammatory activity of Terminalia paniculata was studied against carrageenan-induced hind paw edema, air pouch inflammation and complete Freund's adjuvant (CFA)-induced arthritis in rats. The aqueous extract of Terminalia paniculata bark (TPW) was administered at the concentrations of 100, 200 and 400 mg/kg body weight.

Results

TPW showed significant (p < 0.05) anti-inflammatory activity by reducing the edema volume in carrageenan-induced paw edema in rats. Further, TPW (400 mg/kg) also reduced the carrageenan-induced leukocyte migration (50.92 ± 5.71%) and myeloperoxidase activity (49.31 ± 5.24%) in air pouch exudates. TPW (200 mg/kg) exhibits anti-rheumatic and analgesic activities by improving the altered haematological milieu (ESR, CRP, RF, WBC, RBC and Hb) and also by inhibiting the flexion scores and radiographic changes in CFA-induced arthritis. This extract also had significant (p < 0.05) effects on the occurrence of secondary lesions compared to CFA control.

Conclusions

Terminalia paniculata bark may be a potential preventive or therapeutic candidate for the treatment of chronic inflammation and arthritis.     

Anti-allergic activity of German chamomile (Matricaria recutita L.) in mast cell mediated allergy model

Ethnopharmacological relevance

Chamomile is most popular used medicinal plant and extensively consumed as a tea or tisanes. Traditionally this plant was used for treatment of many ailments such as allergy disorders and inflammatory mediated diseases.

Aim of the study

We investigated the effects of anti-allergic activity of Matricaria recutita L. on mast cell mediated allergic models.

Materials and methods

The protective effect of methanol extract of Matricaria recutita against compound 48/80 induced anaphylaxis and pruritis models for acute phase of hypersensitivity reactions were carried out. The late phase hypersensitivity reactions by compound 48/80 induced mast cell degranulation and histamine release from blood along with serum nitric oxide (NO), rat peritoneal fluid nitric oxide (NO) and bronchoalveolar fluid nitric oxide (NO) levels were measured.

Results

The methanol extract of Matricaria recutita L. showed inhibitory effects on anaphylaxis induced by compound 48/80 and significant dose dependent anti-pruritis property was observed by inhibiting the mast cell degranulation. Mast cell membrane stabilization activity was also observed in compound 48/80 induced mast cell activation. Dose dependent reduction in the histamine release, along with decreased release of serum, rat peritoneal and BAL fluid nitric oxide (NO) levels were observed.

Conclusion

These results suggest that the methanol extract of Matricaria recutita showed potent anti-allergic activity by inhibition of histamine release from mast cells.     

The analgesic and anti-rheumatic effects of Thladiantha dubia fruit crude polysaccharide fraction in mice and rats

Ethnopharmacological relevance

The fruit of Thladiantha dubia has been used in Chinese manchu nationality folk medicine for treatment of various pains, such as rheumatic pain, lumbocrural pain, and dysmenorrhea. The aim of the present study was to evaluate the anti-rheumatic effect of Thladiantha dubia fruit crude polysaccharide (TF-P) fraction in rats.

Materials and methods

TF-P was evaluated in mice for analgesic activity using acetic acid-induced abdominal contractions test and for anti-inflammatory activity using xylene-induced ear oedema model. Moreover, rheumatoid arthritis (RA) was induced by injection of CFA into the subplantar surface of the hind paw of the male Wistar rats. Joint swelling was measured. In order to evaluate the effect of TF-P on disease progression, proinflammatory mediators (TNF-α and IL-2), and antioxidant indicators (SOD, MDA, and NO) were determined in rats induced by CFA. Pathologic changes of RA in rats were also observed under light microscope.

Results and conclusions

In the present study, TF-P at the dose of 200 mg/kg (according to the clinical traditional dosage) significantly reduced writhings and stretchings induced by the acetic acid in mice. TF-P significantly inhibited xylene-induced ear oedema in mice, compared with control group. TF-P significantly inhibited inoculated and non-inoculated joint swellings in rats induced by CFA. TF-P had no effect of body weight in rats. The histopathological analysis suggested that TF-P obviously alleviated the degree of RA rats. TF-P treated rats preserved a nearly normal histological architecture of the joint.Results of the present study confirm the use of Thladiantha dubia traditionally for the treatment of painful and inflammatory conditions. Those results suggest TF-P has protective and therapeutic effects on RA rats induced by CFA.     

Therapeutic effects of total coumarins from Urtica dentata Hand on collagen-induced arthritis in Balb/c mice

Ethnopharmacological relevance

Urtica dentata Hand (UDH), the root of Laportea bulbifera (Sieb. et. Zucc.) Wedd, has long been utilized in traditional Chinese medicine for the treatment of rheumatoid arthritis and some other autoimmune diseases. Coumarins are the main active principles contributing to UDH's efficacy, but the mechanisms have not been fully clarified.

Aim of study

To explore effects of total coumarins (TC) isolated from UDH on the development of type II collagen (CII)-induced arthritis (CIA) in Balb/c mice.

Materials and methods

Arthritis was induced in Balb/c mice by immunization with an emulsion of 200 mg CII and complete Freund's adjuvant (CFA). The CIA mice were then given with a suspension of TC or saline by intragastric (i.g.) administration every other day. The incidence and severity of disease and histopathology of inflammation were assessed. Inflammatory response was determined by measuring the levels of different inflammation mediators in serum. The effect of TC on differentiation of CD4⁺CD25⁺ Foxp3⁺Treg cells was examined by flow cytometry. The phenotype of bone marrow-derived dendritic cells (DCs), T-bet mRNA level and IL-12p70 secretion by DCs were also detected.

Results

Pharmacologically, treatment with TC for type II collagen induced arthritis in mice through oral administration displayed significant and dose-dependent drop of clinical arthritis score and paw swelling, compared with the untreated CIA mice. Pathologic changes showed that TC protected tissues against bone destruction, whereas an almost complete destruction occurred in the CIA model group. The protective status was associated with a substantial decrease in the production of IFN-γ and IL-2, an increase of IL-10 and TGF-β and suppressive expression of T-bet in DCs. TC also induced the generation of CD4⁺CD25⁺ Treg cells with a Treg phenotype Foxp3. TC-treated DCs were characterized as low expression of MHC class II and CD86 molecules, as well as a reduction of IL-12p70.

Conclusions

Our data suggest that TC provides substantial therapeutic protection against CIA by eliciting immune tolerance and it would be a valuable candidate for further investigation as a new anti-arthritic agent.     

Effect of Feining on bleomycin-induced pulmonary injuries in rats

Ethnopharmacological relevance

The flowers of Gentiana veitchiorum has been widely used in decoction form in the traditional medicine of Tibet against tussis, tracheitis, angina for their anti-inflammatory, antimicrobial and alexipharmic properties.

Aim of the study

The aim of current study was to evaluate the therapeutic effects of Feining, a Chinese herbal formula (national invention patent: ZL200510042636.3) against pulmonary injuries and to clarify the mechanisms involved.

Materials and methods

Experimental pulmonary injuries were induced by bleomycin (BLM) in rats with or without subsequent treatment of Feining or prednisone as positive control. The pulmonary injuries were evaluated by histological analysis. Also, the levels of superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH) and hydroxyproline (Hyp) in the lung tissue were determined. To clarify one of the possible active principles responsible for Feining, high performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS) method was applied to identify the components of Gentiana veitchiorum, one of major ingredients of Feining.

Results

Feining significantly improved lung alveolitis scores and reduced the Hyp content of lungs, which is an index of collagen accumulation. Moreover, Feining played a role against the oxidative damages by decreasing the MDA level, whereas increasing SOD and GSH activity, which correlated with oxidation resistance and scavenging of free radicals. In addition, Feining alleviated inflammatory lung injury by decreasing tumor necrosis factor-α (TNF-α) expression. HPLC-DAD-MS analysis revealed that there was 1.97% gentiopicroside in Gentiana veitchiorum.

Conclusion

Feining has certain therapeutic effects against pulmonary injuries.     

Effects of Rubus coreanus extract on visual processes in bullfrog's eye

Ethnopharmacological relevance

The fruit of Rubus coreanus (Rosaceae) is traditionally used as an aphrodisiac, astringent, restorative and tonic in Asian countries. It is advised for treating diseases related to liver, kidney and urinary dysfunction, premature greying, blurred vision, infertility, impotence and premature ejaculation. Additionally, there is a long history of different parts of the plants being used in the treatment of ophthalmic diseases. However, no scientific studies have been undertaken to determine the effects of Rubus coreanus in visual processes of the vertebrate retina.

Aim of study

The purpose of the present study was to investigate the positive effects of Rubus coreanus extracts on visual processes in the vertebrate's eye.

Materials and methods

Electroretinogram (ERG) techniques were used to record the responses from a bullfrog's eye cup preparations. Active pharmacological agents were used to block specific receptors in the retina and to leave others unaffected. Lipid peroxidation in the retina was generated by adding FeSO₄ + Na-ascorbate.

Results

It was observed that both dark- and light-adapted ERG b-wave peak amplitude significantly increases with Rubus coreanus treatment. It was found that Rubus coreanus acts as a retinal neural antagonist but not as GABA receptor antagonist. Rubus coreanus treatment lowered the duration of rhodopsin regeneration. The results obtained indicated that Rubus coreanus protects against lipid peroxidation drop off ERG amplitude in retina.

Conclusion

Based on results obtained, it is suggested that Rubus coreanus can potentially improve visual sensitivity and can be used to treat pathophysiological conditions of eye.     

Inhibitory effects of the root extract of Dipsacus asperoides C.Y. Cheng et al T.M.Ai on collagen-induced arthritis in mice

Ethnopharmacological relevance

Dipsaci radix, the dried root of Dipsacus asperoides C.Y. Cheng et al T.M.Ai is used as a medicinal plant in oriental clinics for the treatment of bone diseases and functions by strengthening bone and healing bone fractures.

Aim of the study

This study investigated the therapeutic efficacy of Dipsaci radix in treating rheumatoid arthritis using a type II collagen (CII)-induced arthritis (CIA) mouse model.

Materials and methods

Arthritis was induced in male DBA/1 mice by immunization with CII. Dipsaci radix water (DR-W) extract at 50 mg/kg and 100 mg/kg was orally administered from days to after the induction of arthritis. Arthritic score, serum levels of anti-CII IgG2a, the inflammatory mediator prostaglandin E₂ (PGE₂), and inflammatory cytokines (TNF-α, IL-1β and IL-6), and histological changes in the ankle joint were analyzed in CIA mice.

Results

Arthritic induction increased the arthritic score, as well as serum levels of anti-CII IgG2a antibody, PGE₂, TNF-α, IL-1β and IL-6 in mice. However, administration of DR-W extract in CIA mice significantly reduced arthritic scores and serum levels of anti-CII IgG2a antibody, PGE₂, TNF-α, IL-1β and IL-6 compared with those in vehicle-treated CIA mice. Furthermore, histopathological improvement in joint architecture was also observed in DR-W extract-treated CIA mice.

Conclusions

DR-W extract has anti-inflammatory and anti-arthritic effects in arthritic mice. This suggests that Dipsaci radix might be used as a therapeutic agent for the treatment of human arthritis.     

Increased sexual motivation in female rats treated with Humulus lupulus L. extract

Aim of the study

To evaluate the influence of Humulus lupulus extract on sexual behavior in female rats.

Materials and methods

Ovariectomized rats hormonally primed with estradiol benzoate (1.5 μg/rat) and progesterone (500 μg/rat) were acutely treated by oral gavage with Humulus lupulus extract dosed at 5, 10 and 25 mg/kg and then tested for partner preference and sexual receptivity.

Results

The administration of Humulus lupulus extract at the highest dose significantly increased the preference for the stimulus male during the partner preference test and the number of proceptive behaviors during the receptivity test, without affecting the lordosis response.

Conclusions

Humulus lupulus extract increased sexual motivation in hormone-primed female rats.     

Effects of Scutellariae radix and Aloe vera gel extracts on immunoglobulin E and cytokine levels in atopic dermatitis NC/Nga mice

Aim of the study

The present study aimed to investigate the effects of Scutellariae radix (SR) and Aloe vera gel (AV), alone or in combination, on levels of immunoglobulin E (IgE) and inflammatory cytokines in spontaneous atopic dermatitis(AD)-like skin lesions.

Materials and methods

After spontaneous AD-like skin lesion was developed by adaptation to conventional conditions, mice were randomly assigned to control, SR (50 mg/kg, p.o.), AV (0.8 mg/kg, p.o.) and SRAV (50 mg of SR and 0.8 mg of AV/kg, p.o.) groups, and were treated for 6 weeks.

Results

SR and SRAV suppressed IL-5 levels compared with control, but had no effects on IgE levels (P < 0.05). AV increased IgE levels, but decreased both IL-5 and IL-10 compared with control (P < 0.05).

Conclusion

These results suggest that SR and AV modulate immunological responses in AD, mainly through influencing IL-5 or IL-10 levels.     

In vivo anti-tussive activity and structural features of a polysaccharide fraction from water extracted Withania somnifera

Aim of the study

Anti-tussive drugs are amongst the most widely used medications worldwide; however no new class of drugs has been introduced into the market for many years. The present study aims at evaluating the structural features and in vivo anti-tussive activity of a polysaccharide fraction from water extracted Withania somnifera.

Materials and methods

Herein, we have analyzed water extracted material of Withania somnifera using chemical, chromatographic, spectroscopic and biological methods.

Results

A polysaccharide fraction (F3) containing arabinosyl, galactosyl and galacturonosyl residues were obtained by anion exchange chromatography of the water extracted material. This polymer is branched and contained (1,5)-/(1,3,5)-linked arabinofuranosyl, (1,3)-/(1,6)-/(1,3,6)-linked galactopyranosyl residues together with small amount of terminal rhamnopyranosyl and terminal arabinofuranosyl residues. Peroral administration of this pectic arabinogalactan in a dose of 50 mg kg⁻¹ body weight (b.w.) decreased the number of cough efforts induced by citric acid in guinea pigs like that of codeine.

Conclusions

This study provides a scientific basis for the past and present ethnomedical uses of this plant.     

Topical anti-inflammatory and analgesic activity of kirenol isolated from Siegesbeckia orientalis

Ethnopharmacological relevance

Siegesbeckia orientalis has been traditionally used as a topical anti-inflammatory and analgesic agent.

Aims of the study

Current study was designed to explore the topical anti-inflammatory and analgesic effects of a constituent isolated from Siegesbeckia orientalis (Compositae), in order to validate its folk use.

Materials and methods

Kirenol was isolated from ethanolic extract of Siegesbeckia orientalis. Several topical formulations containing kirenol were investigated for anti-inflammatory and analgesic activities in rat. The effects were studied using carrageenan-induced rat acute inflammation model, complete Freund's adjuvant (CFA)-induced chronic inflammation and formalin test in rats. Piroxicam gel and methyl salicylate ointment were studied as positive control for anti-inflammatory and analgesic activity, respectively.

Results

The anti-inflammatory effect of kirenol 0.4-0.5% (w/w) was similar to the effect of piroxicam gel 4 h after carrageenan injection. The analgesic activity of topical preparation with more than 0.4% (w/w) was observed in the late phase. These effects may be due, at least in part, to the pro-inflammatory cytokine production of IL-1β and TNF-α. The administration of kirenol cream at the dose of 0.3, 0.4 and 0.5% (w/w) significantly inhibited the development of joint swelling induced by CFA, which was auxiliary supported by histopathological studies.

Conclusion

Kirenol has demonstrated its significant potential to be further investigated for its discovery as a new lead compound for management of topical pain and inflammation, although further pharmacological research is necessary to fully understand its mechanism of action. It also supports the potential beneficial effect of topically administered Siegesbeckia orientalis in inflammatory diseases.     

Typhonium flagelliforme induces apoptosis in CEMss cells via activation of caspase-9, PARP cleavage and cytochrome c release: Its activation coupled with G0/G1 phase cell cycle arrest

Ethnopharmacological relevance

The plant Typhonium flagelliforme (TF), commonly known as ‘rodent tuber’ in Malaysia, is often used as traditional remedy for cancer, including leukemia.

Aim of the study

We had previously identified morphologically that the linoleic acid rich fraction (DCM/F7) from the tubers of this plant induces selective anti-proliferative effects and apoptosis in CEMss cells. In this present study, we subjected the same DCM/F7 fraction to cell based activity analyses in order to determine the possible mechanism of cell death in leukemic CEMss cells in vitro.

Materials and methods

Extraction of Typhonium flagelliforme tuber has done and fractionation has been done by vacuum liquid column chromatography. The anti-proliferative activity was assayed using MTT and the apoptosis detection was done by Annexin V and DNA laddering assay. Colorimetric caspase assay and immunoblot analysis were employed to detect the expression of protein associated with cell death. Cell cycle analysis was done using flow cytometry.

Results

We found that the cancer inhibitory effect of the DCM/F7 fraction in CEMss cells was 3 ± 0.08 μg/ml (IC₅₀). An early apoptotic induction in CEMss cells was observed by Annexin V assay, which showed a clear dose-dependent DNA fragmentation being observed in gel electrophoresis at 10 and 20 μg/ml. The DCM/F7 fraction at 3 μg/ml significantly arrested CEMss cells at G0/G1 phase (p < 0.05). A constant but increasing pattern-related Sub-G0/G1 index was observed between 12 and 72 h treatment. In relation to this, we further investigated the biochemical events leading to cell death and found that the DCM/F7 fraction increased the cellular levels of caspase-3 and -9 on treated cells. Our results indicated that cytochrome c from mitochondria into the cytosol increased gradually as the DCM/F7 concentration increases, which later lead to the subsequent cleavage of PARP in to 85 kDa fragments. On the contrary, Bcl-2 protein was found to decrease concomitantly during treatment.

Conclusions

Collectively, results presented in this study demonstrated that the DCM/F7 fraction inhibited the proliferation of leukemia cells, leading to the programmed cell death, which was confirmed to be through the mitochondrial pathway.     

Antinociceptive and hypnotic properties of Celastrus orbiculatus

Ethnopharmacological relevance

Celastrus orbiculatus, a woody vine of the Celastraceae family, has been widely used as a traditional medicine for the treatment of many diseases, including rheumatoid arthritis and odontalgia. In this study, we assessed the sedative and antinociceptive activities of the methanolic extract of Celastrus orbiculatus (MCO).

Materials and methods

The antinociceptive effect of MCO was evaluated using several experimental pain models, including thermal nociception methods, such as the tail immersion and the hotplate tests, as well as chemical nociception induced by intraperitoneal acetic acid and subplantar formalin administration in mice. To verify the possible connection of the opioid receptor to the antinociceptive activity of MCO, we performed a combination test with naloxone, a nonselective opioid receptor antagonist. The sedative effect of MCO was studied using the pentobarbital-induced sleeping model.

Results

MCO demonstrated strong and dose-dependent antinociceptive activity compared to tramadol and indomethacin in various experimental pain models. The combination test using naloxone revealed that the antinociceptive activity of MCO is associated with activation of the opioid receptor. MCO also caused decreased sleep latency and increased sleeping time in the pentobarbital-induced sleeping model; however, MCO alone did not induce sleep.

Conclusions

In the present study, MCO showed potent antinociceptive and sedative activities. Based on these results, MCO may be considered a valuable anti-nociceptive and hypnotic agent for the treatment of various diseases.