The neuromuscular blockade produced by pure alkaloid,mitragynine and methanol extract of kratom leaves (Mitragyna speciosa Korth.)

Aim of the study

The effects of pure alkaloid, mitragynine and a methanolic extract of kratom leaves were investigated on neuromuscular junction and compound nerve action potential.

Materials and methods

Wistar rats were killed by cervical dislocation and decapitated. The phrenic nerve–hemidiaphragms, hemidiaphragms and sciatic nerve were isolated.

Results

Kratom methanolic extract present at 0.1–1 mg/mL and mitragynine (0.0156 mg/mL) decreased the muscle twitch on the isolated phrenic nerve–hemidiaphragm and hemidiaphragm preparation. Muscle relaxation caused by kratom extract (1 mg/mL) was greater than the effect of mitragynine. Pancuronium and succinylcholine potentiated the effect of kratom extract. It also had a direct relaxation effect on the hemidiaphragm muscle. The muscle relaxation caused by kratom extract was not antagonized by neostigmine, tetraethylammonium and calcium chloride. High concentrations of kratom extract (10–40 mg/mL) and mitragynine (2 mg/mL) blocked the nerve conduction, amplitude and duration of compound nerve action potential.

Conclusions

The mechanism of action of kratom extract might not act as a competitive antagonist of acetylcholine yet its dominant effect was at the neuromuscular junction and not at the skeletal muscle or somatic nerve.     

M3 muscarinic receptor- and Ca influx-mediated muscle contractions induced by croton oil in isolated rabbit jejunum

Aim of study

Croton oil is the fruit oil of Croton tiglium L., which is well known in folk medicine for the treatment of gastrointestinal (GI) diseases, including constipation, abdominal pain, peptic ulcer, and intestinal inflammation for a long period. This study was to investigate the pharmacological effect of croton oil on GI tract.

Materials and methods

The effect of croton oil on the smooth muscle contractions was investigated in vitro using the isolated rabbit jejunum model.

Results

Croton oil has a biphasic action contracting and relaxing intestinal tissue. At the concentrations of 20–80 μg/mL, croton oil produced a concentration-dependent increase in the amplitude and tension of muscle contractions, whereas at high concentrations (>200 μg/mL) it decreased the contractile amplitude and had no impact on the tension. Moreover, croton oil was less effective in increasing muscle amplitude and tension than Ach, confirming that the effect of croton oil on muscle contractions is not a simply stimulatory or inhibitory action, but a unique modulatory process depending on the concentration of croton oil. In addition, croton oil concentration-dependently suppressed the frequency of muscle contractions. On the other hand, atropine (10 μM) and 4-DAMP (10 μM) produced a significant inhibition of contractions caused by croton oil, while either hexamethonium (10 μM) or methoctramine (10 μM) was inactive, implying that the regulatory effects of croton oil on GI motility are mediated via the activation of M3 muscarinic receptor. Furthermore, muscle contractions induced by croton oil were dramatically reduced by verapamil (0.1 μM) but not by NE (1 μM), suggesting that the action of croton oil on GI motility is also mediated by Ca²⁺ influx through L-type Ca²⁺ channel.

Conclusions

The results suggest that croton oil possesses spasmogenic and spasmolytic properties and the regulatory effects of croton oil on GI motility are mediated via the activation of M3 muscarinic receptor and Ca²⁺ influx through L-type Ca²⁺ channel.     

Depressant effects of Clinopodium mexicanum Benth. Govaerts (Lamiaceae) on the central nervous system

Ethnopharmacological relevance

The decoction of leaves of Clinopodium mexicanum Benth. Goaverts (Lamiaceae), commonly known as “Toronjil de Monte”, is used in the Mexican traditional medicine to induce sleep, as well as sedative and analgesic remedy.

Aim of the study

To evaluate the putative depressant effects of an aqueous extract of the medicinal plant Clinopodium mexicanum on the central nervous system (CNS).

Materials and methods

The effects of the extract (AECM) on mice were tested in several animal paradigms, including sodium pentobarbital-induced sleep, open field tests, and hole-board tests. The effects of AECM on pentylenetetrazole- and picrotoxin-induced convulsions in mice and on the antithermonociceptive response in the hot-plate paradigm were also tested. Additionally, the active extract (AECM) was analyzed with HPLC–ESI-MS techniques.

Results

Mice acutely treated with AECM at 100, 200, 500 and 1000 mg/kg doses prolonged the sleeping time induced by sodium pentobarbital (42 mg/kg). This extract, at 100 and 200 mg/kg doses, showed a sedative effect in the hole-board paradigm and decreased spontaneous activity in mice. AECM at 10, 100 and 200 mg/kg prolonged the onset of seizures induced by pentylenetetrazole (90 mg/kg) and antagonized tonic convulsions induced by picrotoxin (10 mg/kg). Additionally, AECM inhibited the response to a thermonociceptive stimulus. The intraperitoneal AECM treatment produced mortality with an LD₅₀ = 2154 mg/kg. Chemical analysis showed that the flavanone glycosides neoponcirin, poncirin, and isonaringenin are the main compounds of the active extract.

Conclusions

This study demonstrates that an acutely administered single dose of an aqueous extract of Clinopodium mexicanum can exert depressant effects on the CNS. These findings are in agreement with the traditional use of Clinopodium mexicanum to induce sleep as well as sedative and analgesic remedy. The chemical analysis of AECM revealed the presence of the flavanone glycosides neoponcirin, poncirin, and isonaringin.     

Antispasmodic effect of Mentha piperita essential oil on tracheal smooth muscle of rats

Aim of the study

Mentha piperita is a plant popularly known in Brazil as “hortelã-pimenta” whose essential oil is used in folk medicine for its anti-inflammatory, antispasmodic, expectorant actions and anti-congestive. Here, it was investigated the effect of Mentha piperita essential oil (peppermint oil) in rat tracheal rings along with its mechanism of action.

Materials and methods

Tracheal tissue from Male Wistar rats (250–300 g) were used. Peppermint oil was added in cumulative concentrations [1–300 μg/ml] to the tissue basal tonus or pre-contracted by carbachol [10 μM] at 10 min intervals, incubated or not with indomethacin [10 μM], l-N-metyl-nitro-arginine [100 μM], hexamethonium [500 μM], or tetraethylammonium [5mM].

Results

Peppermint oil [100 and 300 μg/ml] inhibited the contractions induced by carbachol, which was reversed by indomethacin, l-N-metyl-nitro-arginine and hexamethonium, but not by tetraethylammonium. These data suggest the participation of prostaglandin E₂, nitric oxide and autonomic ganglions in the peppermint oil relaxant effect and may be correlated with its popular use in respiratory diseases.

Conclusions

Peppermint oil exhibited antispasmodic activity on rat trachea involving prostaglandins and nitric oxide synthase.     

Sedative and hypnotic effect of freeze-dried paeoniflorin and Sini San freeze-dried powder in pentobarbital sodium-induced mice

Objective

To investigate the sedative and hypnotic activity of paeoniflorin and freeze-dried Sini San powder on mice and provide a reliable method for determining the pharmacodynamic material basis of Sini San.

Methods

Male adult mice weighing 20–22 g were used in this study. Three experiments were carried out. Synergism with pentobarbital was used as an index for hypnotic effect. Loss of the righting reflex was used to determine the start of sleep. Sleep latency and sleeping time were recorded in each experiment.

Results

The coefficient of variation of the supra-threshold dose (55 mg/kg) was significantly lower than that of the threshold dose. The sleep latency of mice was significantly decreased, and the sleeping time of mice was significantly prolonged. The effects of paeoniflorin and Sini San on prolonging the sleeping time of mice induced by pentobarbital sodium were significantly stronger than those in the control group.

Conclusion

Paeoniflorin produces significant sedative and hypnotic effects, and there is an obvious dose-effect relationship.     

Sedative, antiepileptic and antipsychotic effects of Viscum album L. (Loranthaceae) in mice and rats

Ethnopharmacological relevance

Viscum album L. is claimed in traditional medical practice, to be useful in the treatment of epilepsy and insomnia in Himachal Pradesh, India.

Materials and methods

The effect of Viscum album L. on epilepsy, psychosis and sedative activity was evaluated in mice and rats using standard procedure.

Results

The aqueous leaf extract of Viscum album L. prolonged the pentobarbital induced sleeping time and reduced the locomotor activity in actophotometer. This suggests that reduced locomotor activity facilitate GABAergic transmission. In addition the extract reduced MES, INH and PTZ-induced convulsions which suggest that there may be possibility of blocking Na⁺ channels, opening of Cl⁻channels or enhancing the GABAergic system. The extract decreased the apomorphine-induced stereotyped behavior and potentiates the HAL-induced cataleptic score which suggests the extract possess antidopaminergic activity.

Conclusion

The results obtained in present study suggested that title plant exhibited sedative, antiepileptic and antipsychotic activity in mice and rats.     

Evaluation of anxiolytic and sedative effects of 80% ethanolic Carica papaya L. (Caricaceae) pulp extract in mice

Ethnopharmacological relevance

Carica papaya has been used in the Ethiopian traditional medicine to relieve stress and other disease conditions.

Aim of the study

The present study was undertaken to evaluate the anxiolytic and sedative effects of 80% ethanolic Carica papaya (Caricaceae) pulp extract in mice.

Materials and methods

Carica papaya pulp extract was screened for anxiolytic effect by using elevated plus maze, staircase and open field tests, and ketamine-induced sleeping time test for sedation at doses of 50, 100, 200, 400 mg/kg. Distilled water and Diazepam were employed as negative and positive control groups, respectively.

Results

Carica papaya pulp extract 100 mg/kg significantly increased the percentage of open arm time and entry, and reduced the percentage of entry and time spent in closed arm in elevated plus maze test; reduced the number of rearing in the staircase test; and increased the time spent and entries in the central squares while the total number of entries into the open field were not significantly affected, suggesting anxiolytic activity without altering locomotor and sedative effects. A synergistic reduction in the number of rearing and an inverted U-shaped dose response curves were obtained with important parameters of anxiety

Conclusions

The results of this study established a support for the traditional usage of Carica papaya as anxiolytic medicinal plant.     

Sedative and anticonvulsant activities of methanol extract of Dorstenia arifolia in mice

Ethnopharmacological relevance

Dorstenia arifolia is a plant that has been used in the folk medicine to produce hypnotic, sedative and ansiolitic effects but the pharmacological properties have not yet been studied. In addition, the smoke of its rhizome is reputed to induce lethargic sensation.

Aims of the study

The present study investigated possible activities of the methanol extract (ME) of Dorstenia arifolia rhizome on the central nervous system (CNS).

Materials and methods

ME was tested for sedative, hypnotic and anticonsulsant effects using locomotor activity evaluation, pentobarbital-induced sleeping time and pentylenetetrazol (PTZ)-induced convulsion, respectively.

Results

Intraperitoneal administration of ME (10 and 50 mg/kg) significantly decreased locomotor activity from 205.2 ± 25.6 movements/min (DMSO) to 112.1 ± 18.4 (P < 0.05) and 114.9 ± 16.9 (P < 0.05), respectively. Flumazenil (10 mg/kg), an antagonist of GABA_A receptor, prevented the ME-induced sedation. Treatment with ME (50 mg/kg) significantly increased the duration of pentobarbital-induced sleeping time from 41.0 ± 2.3 to 57.9 ± 2.9 min (P < 0.05). The latencies to seizures after intraperitoneal injection of PTZ was recorded and compared between groups. ME promoted a significant protection of PTZ-induced seizures and mortality in a dose-dependent manner.

Conclusions

Our findings indicate that ME of Dorstenia arifolia rizhome has pronounced central effects, and that the sedative and anticonvulsant activities may be related to a facilitation of the GABAergic transmission.     

Isolation of jacaranone,a sedative constituent extracted from the flowers of the Mexican tree Ternstroemia pringlei

Ethnopharmacological relevance

Ternstroemia pringlei represents one of the most widely employed and commercially exploited medicinal plant in Mexico, used popularly as a tranquilizer and for the treatment of insomnia.

Aim of the study

To investigate the sedative constituents of the plant through a bio-guided fractionation of extracts derived from calyx and fruits.

Materials and methods

Crude extracts with different polarities (CHCl₃, AcOEt, MeOH, aqueous) were prepared and subjected to chromatographic fractionation, leading to the isolation of the sedative compound (1) from the MeOH crude extract. The identity of 1 was unequivocally established by means of 1D and 2D NMR spectroscopic analysis. The sleeping time induced by sodium pentobarbital and the elevated plus-maze models were performed on mice to determine the sedative and anxiolytic activities, respectively. Bioactivity was also investigated though in vitro GABA release experiments using mice brain slices.

Results

The sedative compound was established as jacaranone (1), and its effect was clearly demonstrated through a dose-dependent response analysis (ED₅₀ = 25 mg/kg mouse weight). When tested in the elevated plus-maze model, none of the extracts from Ternstroemia pringlei displayed anxiolytic activity. GABA release experiments showed that the MeOH and aqueous crude extracts released this neurotransmitter at a ratio of 217 and 179 pmol/g protein, respectively, evidencing the presence of other bioactive constituents in the extracts apart of 1, whose activity was absent in this model.

Conclusions

Although 1 has been isolated and identified in a number of plant species, this is the first time that its sedative effect has been demonstrated. No previous record exists of other sedative compounds having been isolated from Ternstroemia pringlei.     

Anti-hypoxic activity of the ethanol extract from Portulaca oleracea in mice

Aim of the study

To investigate the effects of the ethanol extract from Portulaca oleracea (EEPO) on hypoxia models mice and to find the possible mechanism of its anti-hypoxic actions so as to elucidate the anti-hypoxia activity and provide scientific basis for the clinical use of Portulaca oleracea.

Materials and methods

EEPO was evaluated on anti-hypoxic activity in several hypoxia mice models, including closed normobaric hypoxia and sodium nitrite or potassium cyanide toxicosis. To verify the possible mechanism(s), we detected the activities of pyruvate kinase (PK), phosphofructokinase (PFK), lactate dehydrogenase (LDH) and the level of adenosine triphosphate (ATP) in mice cortices.

Results

Given orally, the EEPO at doses of 100, 200, 400 mg/kg could dose-dependently enhance the survival time of mice in both of the normobaric and chemical hypoxia models. The activity of the glycolysis enzymes and the level of ATP were higher than those of the control. In the pentobarbital sodium-induced sleeping time test and the open-field test, EEPO neither significantly enhanced the pentobarbital sodium-induced sleeping time nor impaired the motor performance, indicating that the observed anti-hypoxic activity was unlikely due to sedation or motor abnormality.

Conclusions

These results demonstrated that the EEPO possessed notable anti-hypoxic activity, which might be related to promoting the activity of the key enzymes in glycolysis and improving the level of ATP in hypoxic mice.     

Neuropharmacological in vivo effects and phytochemical profile of the extract from the aerial parts of Heteropterys brachiata (L.) DC. (Malpighiaceae)

Ethnopharmacological relevance

Heteropterys brachiata is a plant species that has been used in traditional Mexican medicine for the treatment of nervous disorders.

Aim of the study

To evaluate the anxiolytic, anticonvulsant, antidepressant and sedative effects produced by the methanolic extract of Heteropterys brachiata (HbMeOH) in ICR mice. Additionally, we determine the acute toxicity profiles of the extract and the presence of its main constituents.

Material and methods

The neuropharmacological effects of the extract were evaluated using a variety of models, such as the elevated plus maze (EPM), the forced swimming test (FST), the pentobarbital potentiation test (PTBt), pentylenetetrazole-induced seizures test (PTZt), and the open field test (OFT). HPLC was employed for obtention of phytochemical profile.

Results

HbMeOH produced a significant antidepressant effect in FST at 500 and 750 mg/kg doses, while doses from 500 to 1500 mg/kg exhibited a clear dose-dependent anxiolytic activity in EPM. A dose of 500 mg/kg showed a significant anticonvulsant activity in PTZt and an absence of sedation effects in PTBt. The main compounds of HbMeOH were chlorogenic acid and chlorogenic acid methyl ester, as well as less abundant terpene-type compounds. Furthermore, the extract was either safe with no deaths in mice treated orally with 2000 mg/kg.

Conclusions

HbMeOH extract which contains mainly hydroxycinnamic acids and triterpene-type compounds, possesses antidepressant, anxiolytic and anticonvulsive properties and can be considered safe or of low toxicity when orally administrated. These findings lend pharmacological justification to the traditional use of Heteropterys brachiata in the treatment of nervous disorders.     

CNS depressant and anticonvulsant activities of the alcoholic extract of leaves of Ziziyphus nummularia

Ethnopharmacological relevance

Ziziyphus nummularia (family: Rhamnaceae) is a xerophyte, grows in the grazing lands of the Thar Desert of Rajasthan. Ziziyphus nummularia (ZN) is used as sedative in ethnomedicine. The objective of this study is to investigate the anticonvulsant, anxiolytic and sedative activities of the alcoholic extract of leaves of Ziziyphus nummularia (EZN).

Materials and methods

The anticonvulsant effect of the EZN (100, 200 and 300 mg/kg) was evaluated in mice using the pentylenetetrazole and maximal electroshock induced seizure models. Its anxiolytic activity was evaluated using the elevated plus maze, hole board and open field models board methods, while the pentobarbital induced sleep was used to evaluate the sedative activity. The acute toxicity and effect on motor coordination were also assessed.

Results

EZN (100–300 mg/kg) protected the mice against the pentylenetetrazole induced convulsions; it causes a significant (P<0.05) dose dependent increase in latency of convulsion. Treatment with EZN reduced the duration of the tonic hind limb extension induced by electroshock. Mice treated with EZN preferred the open arm of the plus maze and were found to be devoid of open-arm avoidance. EZN potentiation the barbiturate induce sleep in mice, it causes a decrease in the sleep latency and increases the duration of sleep.

Conclusion

The results obtained from the experiments indicate that the EZN has CNS depressant and anticonvulsant activities.     

Pharmacological evaluation of sedative–hypnotic activity and gastro-intestinal toxicity of Rhizoma Paridis saponins

Ethnopharmacological relevance

Rhizoma Paridis saponins (RPS) have been well studied for antimicrobial, anti-hemorrhagic, and anticancer effects. However, scientific information on RPS regarding the toxic and neuropharmacological effects is limited. In this study, the acute oral toxicity, sedative–hypnotic activity and gastro-intestinal toxicity of RPS were investigated.

Materials and methods

The acute toxicity was carried out by administering single doses (800–5000 mg/kg) of RPS to adult mice. Rotarod test and sodium pentobarbital-induced hypnosis activity were used to evaluate the neuropharmacological effects on mice. Gastric emptying and intestinal transit were used to investigate the gastric–intestinal system effects.

Results

A single oral administration of RPS dose-dependently caused adverse effects on the general behavior and mortality rate of mice. LD₅₀ value of oral acute toxicity was 2182.4 mg/kg, with 95% confidence limit of 1718.4–2807.8 mg/kg. In the test of sleeping mice, RPS acted in synergy with sodium pentobarbital at doses 250 and 500 mg/kg while motor coordination was not influenced within 120 min after treatment with RPS. Regarding the gastric–intestinal toxicity, RPS (100, 250, and 500 mg/kg) significantly inhibited gastric emptying but did not affect the intestinal transit.

Conclusions

RPS, which is a hypotoxic anticancer drug, possesses the sedative–hypnotic activity and gastric stimulus side effect.     

Anticonvulsant,anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata Fresen.

Aim of the study

The objective of this study is to investigate the anticonvulsant, anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata.

Materials and methods

The anticonvulsant effect of the aqueous root extract (100, 200 and 400 mg/kg) was evaluated in mice using the strychnine- and picrotoxin-induced seizure models. Its anxiolytic activity was evaluated using the elevated plus maze (EPM) and the Y maze (YM) methods (14 and 32) while the hexobarbitone induced sleep and the hole board models were used to evaluate the sedative and exploratory activities in mice respectively. The acute toxicity studies and phytochemical analysis of the extract were also carried out.

Results

The extract (100–400 mg/kg) produced a significant (P < 0.01) dose dependent increase in onset of convulsion compared to the control for strychnine- and picrotoxin-induced seizures. It also produced a significant (P < 0.01) dose dependent prolongation of the cumulative time spent in the open arms of the elevated plus maze and Y maze compared with the control. The extract (100–400 mg/kg) produced significant (P < 0.01) reduction in the time of onset of sleep induced by hexobarbitone. The prolongation of hexobarbitone sleeping time by the extract (200 mg/kg) was comparable to that produced by diazepam (3 mg/kg). At doses of 100–400 mg/kg, the extract produced a dose dependent decrease in exploratory activity of the mice. The reduction in exploratory activity produced by the extract (400 mg/kg) was greater than that of chlorpromazine (1 mg/kg). The results obtained from the experiments indicate that the extract has central nervous system depressant and anxiolytic activities. The LD₅₀ obtained for the acute toxicity studies using both oral and intraperitoneal routes of administration were 1.74 g/kg and 19.95 mg/kg respectively.

Conclusion

These findings justify the use of Securidaca longepedunculata in traditional medicine for the management of convulsion and psychosis.     

Repeated administration of an aqueous spray-dried extract of the leaves of Passiflora alata Curtis (Passifloraceae) inhibits body weight gain without altering mice behavior

Ethnopharmacological relevance

Passiflora alata is a Southern American species that constitutes many traditional remedies as well as phytomedicines used for sedative and anxiolytic purposes in Brazil. However studies on repeated treatment effects are scarce.

Aim of the study

To evaluate behavioral, physiological and biochemical effects of the repeated treatment with an aqueous spray-dried extract of Passiflora alata leaves containing 2.5% (w/v) of flavonoids (PA) in mice.

Material and methods

Male adult CF1 mice were treated (p.o.) for 14 days with PA (2.5; 25 or 250 mg/kg). The feeding behavior was evaluated at the beginning (1 h after the first administration) and at the end of the treatment (15th day). The body weight gain and food consumption were monitored along the days. On day 15 mice were evaluated on plus maze, spontaneous locomotor activity, catalepsy and barbiturate sleeping time tests. Serum glucose, lipids, ALT and AST enzymes were determined. Liver, kidney, perirenal fat, epididymal and peritoneal fat were analyzed.

Results

The repeated treatment with the highest dose tested (250 mg/kg) did not alter the mice behavior on open field, elevated plus maze, catalepsy and barbiturate sleeping time tests. Repeated administration of PA 250 decreased mice feeding behavior and weight gain. PA 25 and PA 250 reduced mice relative liver weight and caused mild hepatic hydropic degeneration as well as a decrease in alanine aminotransferase (ALT) serum level.

Conclusions

These results indicate that Passiflora alata does not present central cumulative effects and point to the needs of further studies searching for its hepatotoxicity as well as potential anorexigenic.     

Sedative, hypnotic and anticonvulsant activities of the ethanol fraction from Rhizoma Pinelliae Praeparatum

Ethnopharmacological relevance

Rhizoma Pinelliae Praeparatum is the product of raw Rhizoma Pinellia processed with alkaline solution and Licorice, which had been widely used for treatment of insomnia in traditional Chinese medicine. The present study aimed to investigate the sedative, hypnotic and anticonvulsant activities of ethanol fraction from Rhizoma Pinelliae Praeparatum (EFRP) and to determine whether these effects were related to GABAergic mechanism.

Materials and methods

The sedative, hypnotic and anticonvulsant activities of EFRP were investigated with locomotion activity, pentobarbital-induced sleeping and nikethamide (NKTM)-induced convulsion tests, respectively. Additionally, the effects of flumazenil (an antagonist of GABA_A receptor) and l-malic acid (blocker of synthetic enzyme for GABA) on the hypnotic activity of EFRP were evaluated.

Results

EFRP at dose of 12 g/kg significantly inhibited the locomotion activity of mice. EFRP showed synergic effect on pentobarbital-induced sleeping by increased numbers of mice falling asleep, reduced the sleep latency and prolonged the sleeping time. l-malic acid and flumazenil inhibited the augment effects of EFRP on pentobarbital-induced sleeping. EFRP promoted a significant protection to NKTM-induced convulsion, by prolonged the death latency and decreased mortality.

Conclusion

EFRP possessed sedative, hypnotic and anticonvulsant activities and these activities may be related to the GABAergic system.     

Antinociceptive effects of ethanolic extract from the flowers of Acmella oleracea (L.) R.K. Jansen in mice

Ethnopharmacological relevance

In Brazil, Acmella oleracea (L.) R.K. Jansen, popularly known as “jambu”, has been used by some communities from Amazon region to treat toothache. In this study we examined the antinociceptive effect of the ethanolic extract obtained from the flowers of Acmella oleracea (EEAO) in animal models of nociceptive (chemical and thermal) and neuropathic (partial sciatic nerve ligation) pain.

Materials and methods

Adult male mice were treated by intraperitoneal route (i.p.) with EEAO before the induction of nociceptive response by formalin, capsaicin and cinnamaldehyde, thermal heat hyperalgesia (hot plate test) and mechanical allodynia (traumatic sciatic nerve injury). Acute toxicity and non-specific sedative effects were evaluated.

Results

EEAO (10, 30 and 100 mg/kg) reduced both neurogenic and inflammatory phases of the formalin- and also capsaicin- and cinnamaldehyde-induced orofacial nociception. Interestingly, EEAO at 100 mg/kg (i.p.) also reversed capsaicin-induced heat hyperalgesia assessed as the latency to paw withdrawal in the hot plate test. Also in the hot plate test, paw withdrawal latency was increased by EEAO (100 mg/kg) and this response was only partially reversed by naloxone. Furthermore, EEAO (100 mg/kg) also reduced mechanical allodynia caused by partial sciatic nerve ligation for 3 h. The estimated LD50 value was 889.14 mg/kg and EEAO did not alter the locomotion of animals in the open-field test.

Conclusion

Taken together, our data show that EEAO produces prevalent antinociceptive effects and does not cause adverse effects. The presence of N-alkylamides, including spilanthol, suggests that the therapeutic effect of EEAO is related to its highest anesthetic activity.     

Anti-inflammatory and analgesic properties of Heracleum persicum essential oil and hydroalcoholic extract in animal models

Ethnopharmacological relevance

Fruits of Heracleum persicum (Apiaceae) are used as pain killer in Iranian folkloric medicine.

Aims of study

To evaluate the anti-inflammatory and analgesic effects of the hydroalcoholic extract and essential oil of the plant fruits and analyzing the essential oil.

Materials and methods

Essential oil and hydroalcoholic extracts of the fruits were prepared according to standard methods and the components of essential oil were identified using GC–MS method. The acetic acid-induced writhing response and formalin test were used in male mice to assess analgesic activity. For evaluation of anti-inflammatory effect, carrageenan-induced rat paw edema was used.

Results

Hexyl butyrate (56.5%), octyl acetate (16.5%), hexyl 2-methylbutanoate (5.2%) and hexyl isobutyrate (3.4%) were identified as the major constituents of the oil. Oral or intraperitoneal administration of Heracleum persicum essential oil (HPEO) at doses of 50–200 mg/kg and Heracleum persicum hydroalcoholic extract (HPHE) at doses of 250 and 500 mg/kg significantly reduced acetic acid-induced abdominal constrictions. HPEO and HPHE also significantly attenuated the pain response of the second phase of formalin test.In carrageenan test HPEO at doses of 100 and 200 mg/kg and HPHE at a dose of 400 mg/kg induced a significant reduction of paw edema.

Conclusions

These results clearly show the analgesic and anti-inflammatory effects of the plant essential oil and hydroalcoholic extract. Further studies are needed to clarify the mechanism of action and the components responsible for these pharmacological effects.     

Neuropharmacological study of Dracocephalum moldavica L. (Lamiaceae) in mice: sedative effect and chemical analysis of an aqueous extract

Ethnopharmacological relevance

Dracocephalum moldavica is used as a tranquilizer and as remedy for nervous conditions relief in the Mexican traditional medicine. Despite its intensive use no literature reported neuropharmacological studies on Dracocephalum moldavica as yet.

Aim of the study

The sedative, anxiolytic-like and antidepressant-like effects of the aqueous extract of aerial parts of Dracocephalum moldavica (Lamiaceae) (DM) were evaluated in behavioral models in mice. The general toxic effects of DM were evaluated as well as their chemical analysis was performed.

Materials and methods

DM effects were evaluated on pentobarbital-induced sleeping time (SPT), the hole-board (HBT), and the avoidance exploratory behavior (AEBT) tests and on the forced swimming test (FST). General activity and motor coordination were evaluated in the open field (OFT) and Rota-rod tests, respectively. The acute toxicity of DM was determinate by its LD₅₀ dose. The chemical analyses DM were performed by chromatographic and HPLC–ESI-MS techniques.

Results

DM prolonged the pentobarbital-induced sleeping time, induced sedation in the HBT, decreased spontaneous activity and produced motor coordination impairment in mice. However, DM did not show anxiolytic effects in the AEBT or HBT and it was not effective in FST. The DM-treatment produced mortalities with LD₅₀ = 470 mg/kg body weight.The HPLC–ESI-MS analysis of DM revealed that (acacetin, apigenin and luteolin)-7-O-β-d-(6″-O-malonyl)-glucoside derivates are the main compounds of DM.

Conclusions

DM induced sedative actions and a general inhibition of CNS activity observed by the decrease of animals’ general activity, motor coordination and exploration.     

Anthelmintic activity of Arisaema franchetianum and Arisaema lobatum essential oils against Haemonchus contortus

Ethnopharmacological relevance

Arisaema franchetianum and Arisaema lobatum are two perennial plants native to China. Arisaema franchetianum is universally used to promote the subsidence of induration and swelling, quicken blood and relieve pains, and kill intestinal parasites in humans and animals. Arisaema lobatum is used to treat malaria, intestinal parasites, and snake and insect bites in humans and animals. The aim of this study was to determine the composition of the essential oils from Arisaema franchetianum and Arisaema lobatum and evaluate the anthelmintic effect against Haemonchus contortus.

Materials and methods

Two oils were investigated by GC and GC–MS. The anthelmintic bioassay tests of Arisaema franchetianum and Arisaema lobatum essential oil, linalool and carvacrol were performed using egg hatch assay (EHA), larval development assay (LDA) and larval migration inhibition assay (LMIA).

Results

Fifty six components representing 96.88% of the Arisaema franchetianum oil and 64 components representing 96.88% of the Arisaema lobatum oil were identified. Carvacrol and linalool were found to be the major constituents of two oils. In the EHA, greater than 99% inhibition were observed with Arisaema franchetianum oil at 10 mg/mL (CE₅₀ 1.63 mg/mL) and Arisaema lobatum oil at 5 and 10 mg/mL (CE₅₀ 0.48 mg/mL). In the LDA, both oils induced complete inhibition at 10 mg/mL, with the CE₅₀ being 1.10 mg/mL for Arisaema franchetianum oil and 0.73 mg/mL for Arisaema lobatum oil. In the LMIA, the Arisaema franchetianum oil and Arisaema lobatum oil at best inhibited 74.1% and 95.6% of larval migration at 10 mg/mL, respectively. Carvacrol exhibited similar activity to Arisaema lobatum essential oil and linalool did not show high activity in every assay.

Conclusions

These data show for the first time that the essential oils obtained from Arisaema franchetianum or Arisaema lobatum had promising anthelmintic activity against Haemonchus contortus. Arisaema plant may offer an alternative source for the control of gastrointestinal nematodes of sheep and goats.