Anxiolytic and sedative activities of Passiflora edulis f. flavicarpa

Aim of the study

Many plants in the genus Passiflora have long been used in traditional folk medicines as a remedy for many neurogenic diseases in many countries. A number of species of the genus was studied about their neuropharmacological activities, but the results were inconsistent. No literature reported neuropharmacological studies on Passiflora edulis f. flavicarpa as yet. The present study was aimed at evaluating the anxiolytic and sedative activities of Passiflora edulis f. flavicarpa.

Materials and methods

Swiss albino mice were used as experimental animals in elevated plus-maze (EPM) test and spontaneous activity (SA) test to assay the behavioral effects of ethanolic extract (EE) of the aerial part of Passiflora edulis f. flavicarpa and its fractions, viz. petrol ether extract (PEE), ethyl acetate extract (EAE), n-BuOH extract (BE) and aqueous extract (AE), together with subfractions of BE, viz. BEF-I, BEF-II, BEF-III, BEF-IV and isoorientin, a flavonoid component isolated from BEF-III.

Results

In the EPM test, single-dose oral administration of EE (300 mg/kg and 400 mg/kg), BE (125 mg/kg and 200 mg/kg), AE (200 mg/kg and 300 mg/kg), BEF-I (200 mg/kg), BEF-II (200 mg/kg), BEF-III (100 mg/kg), or isoorientin (20 mg/kg) resulted in anxiolytic-like effects, but a sedative-like activity was produced at higher doses, such as 300 mg/kg of BE, 200 mg/kg of BEF-III, or 40 mg/kg and 80 mg/kg of isoorientin. The results of the SA test manifested that treatment with 400 mg/kg of EE, 300 mg/kg of BE, or 40 mg/kg and 80 mg/kg of isoorientin compromised motor activity in mice, which are in line with the results of the EPM test.

Conclusions

The aerial part of Passiflora edulis f. flavicarpa was anxiolytic at low dose but sedative at high dose. Flavonoids are important active constituents. Since AE contained little flavonoids, it was conjectured that there were other components responsible for the anxiolytic effect of Passiflora edulis f. flavicarpa besides flavonoids.     

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.     

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.     

Anticonvulsant activity of Benkara malabarica (Linn.) root extract: In vitro and in vivo investigation

Aim of the study

To systematically investigate the anticonvulsant activity of methanol extract of Benkara malabarica roots and to provide a biochemical basis elucidating its mode of action.

Methods

The median lethal dose (LD₅₀) of Benkara malabarica extract was determined. The anticonvulsant activity of the extract was assessed in strychnine-induced and isoniazide-induced convulsion models; phenytoin (20 mg/kg) and diazepam (1 mg/kg) were used as standards, respectively. Percentage protection provided by the drug was accounted as decrease in the number of convulsions within 8 h of observation. Mechanism of action was studied by performing GABA transaminase (GABA-T) assay, isolated from rat brain. Active constituent was isolated and characterized from the plant extract.

Results

The median lethal dose (LD50) of Benkara malabarica was found to be more than 500 mg/kg. It demonstrated 30% and 35% protection against strychnine-induced convulsions and 60% and 80% protection against isoniazide-induced convulsions, at doses of 25 mg/kg and 50 mg/kg, respectively. Enzyme assay results revealed that Benkara malabarica extract possesses GABA-T inhibitory activity (IC50 = 0.721 mg/ml). Scopoletin which was identified as the major constituent of the extract was found to be an inhibitor of GABA-T (IC50 = 10.57 μM).

Conclusions

The anticonvulsant activity of the plant extract is predominantly GABA mediated and may be due to the action of scopoletin alone or is a result of synergy of different compounds in the extract in which scopoletin is the major constituent.     

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.     

In vivo antimalarial activities of Enantia polycarpa stem bark against Plasmodium berghei berghei in mice

Ethnopharmacological relevance

Enantia polycarpa (PC) Engl. Et Diels (Annonaceae) is used in traditional medicine as an antimalarial remedy in Southern Nigeria.

Aim of the study

The antimalarial activities of ethanolic stem bark extracts of Enantia polycarpa was studied in vivo, in mice infected with Plasmodium berghei berghei.

Materials and methods

The ethanolic stem bark extract of Enantia polycarpa was administered at doses ranging from 200 to 600 mg/kg/day to Plasmodium berghei infected mice in both early and established models of antiplasmodial studies.

Results

The extract of Enantia polycarpa exhibited promising antimalarial activity against both early and established infections. At a dose of 600 mg/kg the extract achieved a 75.8% and 72% chemosuppression of parasitaemia in the study of acute and established infections, respectively. The extract also prolonged mean survival time of Plasmodium berghei infected mice during the study of established infection. The mean survival time of mice administered Enantia polycarpa extract at 600 mg/kg/day (27 days) was significantly longer than infected/untreated control (12 days). For the acute toxicity study the extract had an intraperitoneal LD₅₀ of 186 mg/kg but caused no mortality when administered orally at doses as high as 2,000 and 4,000 mg/kg.

Conclusions

Collectively, the results indicate that Enantia polycarpa is safe when administered orally and possesses promising antimalarial activity, thus supporting its use in traditional medicine for the treatment of malaria.     

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.     

Erythropoietic activity of Asteracantha longifolia (Nees.) in rats

Ethnopharmacological relevance

Asteracantha longifolia Nees. (Family-Acanthaceae) is a wild herb commonly used in traditional ayurvedic medicine as Kokilaaksha and the Unani drug as Talimakhana in India and Srilanka for various medicinal uses as aphrodisiac, tonic, sedative and blood diseases etc.

Aim of the study

The aim of the current study was to validate and explore the folk use of Asteracantha longifolia Nees. (AL) (Leaf part) on pharmacological grounds using haloperidol induced iron deficiency anemia for the assessment of erythropoietic activity.

Materials and methods

Determination of iron in plant extracts was carried out using spectrophotometric method. Plant extract was obtained from crude drugs using extraction with ethanol. In vivo study, haloperidol induced iron deficiency anemia model was used in experimental studies.

Results

An administration of ethanolic extract of AL at the doses of 100 mg/kg and 200 mg/kg body weight, i.p., demonstrated a significant (P < 0.05) increase in erythrocyte count, haemoglobin count, serum iron and serum protein etc. This effect may be due to the presence of iron (622 μg/50 mg) in extract estimated by spectrophotometric method.

Conclusion

An ethanolic extract of AL effectively restored the hematological parameters, serum iron and serum protein and normalized the microcytic (smaller in size), anisocytosis (disturbed shape) and hypochromic RBCs. These observations could justify the inclusion of this plant in the management of iron deficiency anemia due the presence of iron and other constituents as flavonoids, terpenoids, steroids, lupeol and betulin.     

The effect of Salvia divinorum and Mitragyna speciosa extracts,fraction and major constituents on place aversion and place preference in rats

Ethnopharmacological relevance

Consumer use of botanicals has increased despite, in many instances, the paucity of research demonstrating efficacy or identifying liabilities. This research employed the place preference/aversion paradigm to characterize the psychoactive properties of Salvia divinorum extract (10, 30, 100 mg/kg), salvinorin A (0.1, 0.3, 1.0 mg/kg), Mitragyna speciosa MeOH extract (50, 100, 300 mg/kg), Mitragyna speciosa alkaloid-enriched fraction (12.5, 25, 75 mg/kg) and mitragynine (5, 10, 30 mg/kg) in rats.

Material and methods

Following apparatus habituation and baseline preference scores, male Sprague-Dawley rats were given eight counter-balanced drug versus vehicle conditioning trials followed by a preference test conducted under drug-free states. S(+)-amphetamine (1 mg/kg) served as the positive control (in Exp. 2) and haloperidol (0.8, 1.0 mg/kg) served as the negative control in both studies.

Results

Rats displayed place aversion to both Salvia divinorum and salvinorin A that exceeded that of haloperidol. Rats showed place preference to mitragynine that was similar to that of S(+)-amphetamine. This CPP effect was much less pronounced with the Mitragyna speciosa extract and its fraction.

Conclusions

These findings suggest that both botanicals possess liabilities, albeit somewhat different, that warrant caution in their use.     

Antinociceptive,neurobehavioral and antioxidant effects of Eupatorium triplinerve Vahl on rats

Ethnopharmacological relevance

Eupatorium triplinerve Vahl belongs to the Asteraceae family, popularly known as Japana. It is a perennial shrub native to Amazon rainforests of South America. Its leaves are used through infusions, decoctions, baths, and tea. It is largely used in Brazilian folk medicine as sedative, febrifuge, stimulant, tonic and anti-inflammatory.

Aim of the study

The present study evaluated the putative effects of Eupatorium triplinerve on the central nervous system (CNS), including locomotor and anxiety activity, depression-like behavior, and antinociception and oxidative stress.

Materials and methods

Two-month-old male Wistar rats (n=7–10 rats/group) and Swiss male and female mice of the species Mus musculus (n=7–10 per group) were administered with 100 mg/kg, 200 mg/kg, 400 mg/kg, 600 mg/kg, and 800 mg/kg of hydroalcoholic extracts of Eupatorium triplinerve (HEET). The behavioral assays included open-field (OF), elevated Plus-maze (EPM), and forced swimming tests (FS). The antinociceptive activity was verified using chemical (acetic acid and formalin) and thermal (hot plate) models of nociception. The oxidative stress levels were measured in rat blood samples after behavioral assays and Trolox equivalent antioxidant capacity (TEAC), nitric oxide and malondialdehyde (MDA) levels were measured in vivo.

Results

Oral pretreatment with HEET reduced the locomotion in OF test (200–800 mg/kg), increased central locomotion and open arms entries in the OF and EPM tests, respectively (600–800 mg/kg), and decreased the immobility time in the FS (200–800 mg/kg). It also reduced the writhing number evoked by acetic acid injection (200–800 mg/kg) and licking time in the first phase of the formalin test (400–800 mg/kg). In the oxidative stress assays, the extract decreased TEAC, Nitric Oxide and MDA levels in response to swimming stress induced in rats.

Conclusions

These results were indicative for the first time that Eupatorium triplinerve exerted mild sedative, anxiolytic and antidepressive effects on the CNS. Antinociceptive effects not related to opioid system and antioxidant activity were also observed. These results support the ethnopharmacological use of Eupatorium triplinerve in popular medicine.     

Antiplasmodial activity of root extract and fractions of Croton zambesicus

Aim of the study

Antiplasmodial activity of root extract and fractions of Croton zambesicus were evaluated to ascertain the folkloric claim of its antimalarial activity and elucidate its antiplasmodial mechanism of action.

Material and method

The crude ethanolic root extract (27–81 mg/kg) and gradient fractions ( n- hexane, chloroform, ethyl acetate and methanol; 54 mg/kg) of Croton zambesicus were investigated for antiplasmodial activity against chloroquine - sensitive Plasmodium berghei infections in mice. The antiplasmodial activity during early and established infections as well as the prophylactic activity were investigated. Chloroquine (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. Oxidant generation potentials of the crude extract and fractions was also evaluated to elucidate their mechanism of action.

Results

The crude root extract (27 – 81 mg/kg) demonstrated significant (P < 0.01–0.001) schizonticidal activity during early and established infections and also had prophylactic activity. The activity was comparable to that of the standard drug used (chloroquine 5 mg/kg, pyrimethamine 1.2 mg/kg). Methanol, ethyl acetate and chloroform fractions had comparative in vivo antiplasmodial activity and oxidant generation potentials.

Conclusion

The antiplasmodial activity of this root extract and fractions which is likely to be through peroxidation confirms the folkloric use of this plant.     

Central nervous system effects and chemical composition of two subspecies of Agastache mexicana; an ethnomedicine of Mexico

Ethnopharmacological relevance

Agastache mexicana subspecies mexicana (Amm) and xolocotziana (Amx) are used in Mexican traditional medicine to relief cultural affiliation syndromes known as “susto” or “espanto”, for “nervous” condition, and as a sleep aid. Despite its intensive use, neuropharmacological studies are scarce, and the chemical composition of the aqueous extracts has not been described. Aims of the study are: (1) To analyze the chemical composition of aqueous extracts from aerial parts of Amm and Amx. (2) To evaluate the anxiolytic-like, sedative, antidepressant-like effects. (3) Analyze the general toxic effects of different doses.

Materials and methods

Anxiolytic-like and sedative effects were measured in the avoidance exploratory behavior, burying behavior and the hole-board tests. The antidepressant-like actions were studied in the forced swimming and tail suspension tests. Finally, general activity and motor coordination disturbances were evaluated in the open field, inverted screen and rota-rod tests. The acute toxicity of Amm and Amx was determined by calculating their LD₅₀ (mean lethal dose). The chemical analyses were performed employing chromatographic, photometric and HPLC–ESI-MS techniques.

Results

Low doses of Amm and Amx (0.1σ1.0 mg/kg) induced anxiolytic-like actions; while higher doses (over 10 mg/kg) induced sedation and reduced the locomotor activity, exerting a general inhibition in the central nervous system (CNS).

Conclusions

Results support the use of Amm and Amx in traditional medicine as tranquilizers and sleep inducers. Additionally, this paper contributes to the knowledge of the chemical composition of the aqueous extracts of these plants.     

Effect of plants used in Mexico to treat gastrointestinal disorders on charcoal–gum acacia-induced hyperperistalsis in rats

Ethnopharmacological relevance

A total of 28 plant extracts, belonging to 26 different plant species are commonly used in Traditional Mexican Medicine for the treatment of gastrointestinal disorders such as diarrhea.

Aim of the study

To evaluate the effect of medicinal plant extracts on induced hyperperistalsis in rats.

Materials and methods

Charcoal meal test was used in this study. Extracts were tested at a dose of 300 mg/kg.

Results

From all the plant extracts tested, only Geranium mexicanum (roots) showed 100% of inhibition. The extracts of Artemisia absinthium, Matricaria recutita, Caesalpinia pulcherrima, Lygodium venustum, Chenopodium ambrosoides (green variety), Aloysia triphylla, Artemisia ludoviciana, Chiranthodendron pentadactylon, and Cocos nucifera showed moderate inhibitory activity with values ranging from 30 to 57%. Their activities were greater than that of or equal to loperamide (34% of inhibition at doses of 10 mg/kg) drug used as control. The remaining plants exhibited marginal or null inhibitory effect on hyperpropulsive movement of the small intestine.

Conclusions

The results obtained in this study give some scientific support to the popular use of 23 of the plants tested for the treatment of gastrointestinal disorders such as diarrhea in Mexican traditional medicine. However, roots of Geranium mexicanum should be used in herbal medicine with care to avoid toxicity.     

Experimental evidence of the anaphrodisiac activity of Humulus lupulus L. in naïve male rats

Ethnopharmacological relevance

In the folk medicine Humulus lupulus L. (hops) is mainly recommended as a mild sedative with antispasmodic and digestive properties. It is also reputed to exert an anaphrodisiac effect but it is still lacking the experimental evidence of this activity.

Aim of the study

To evaluate the influence of Humulus lupulus extract on sexual behavior of both naïve and sexually potent male rats; thereafter to investigate the role of 8-prenylnarigenin (8-PN) in the effect displayed by the hop extract.

Materials and methods

Sprague–Dawley male rats both naïve and sexually potent were acutely administered with the hop extract dosed at 5, 10, 25 and 50 mg/kg. In addition the extract was administered daily for 10 consecutive days at the dose of 0.25 mg/kg/day in sexually potent animals. The pure compound 8-PN was acutely administered in naïve rats at the dosages of 5, 12.5 and 25 μg/kg. All the animals were screened for their sexual behavior manifestation during the mating test.

Results

In naïve rats the acute administration of Humulus lupulus extract at the doses of 25 and 50 mg/kg significantly reduced the percentage of mounting and ejaculating animals, in comparison to vehicle controls. The other parameters recorded during the mating test were not affected by the hop extract. In sexually potent rats nor the acute neither the repeated administration of the extract modified their copulatory behavior.The pure compound 8-PN failed to influence male sexual behavior of naïve rats.

Conclusion

Humulus lupulus extract exerted an anaphrodisiac effect only in naïve rats by inhibiting their mounting and ejaculating behavior. The presence of 8-PN in the extract could be only partially involved in the observed anaphrodisiac effect.     

Characterization of the antinociceptive and anti-inflammatory activities from Cocos nucifera L. (Palmae)

Aim of the study

Cocos nucifera cultivated in Brazil is known as “coco-da-Bahia” or “coqueiro-da-Índia”. The tea from the husk fiber is widely used to several inflammatory disorders. Crude extract and fractions obtained from Cocos nucifera “common variety” were evaluated to test the anti-inflammatory and antinociceptive activities.

Materials and methods

Crude extract (CE, 50, 100, and 150 mg/kg), fraction 1 (F1, molecular weight lesser than 1 kDa, 1, 10, and 50 mg/kg), fraction 2 (F2, molecular weight higher than 1 kDa, 1, 10, and 50 mg/kg), and the references drugs morphine (5 mg/kg), acetilsalicilic acid (200 mg/kg), prometazine (30 mg/kg), and metisergide (5 mg/kg) were evaluated on models of analgesia and inflammation.

Results

CE, F1, and F2 significantly develop peripheral and central antinociceptive activity but with less effect on supra-spinal regions of the brain. Administration of the opioid antagonist, naloxone (5 mg/kg) inhibited the antinociceptive effect indicating that Cocos nucifera crude extract and fractions may be acting in opioid receptors. CE and F1 also inhibited rat paw edema induced by histamine, and serotonin.

Conclusions

results demonstrated that Cocos nucifera and its fractions have antinociceptive and anti-inflammatory activities which confirm the popular use of this plant in several inflammatory disorders.     

Analgesic and antimalarial activities of crude leaf extract and fractions of Acalypha wilkensiana

Aim of the study

Antiplasmodial and analgesic activities of leaf extract and fractions of Acalypha wilkensiana were evaluated to ascertain the folkloric claim of its antimalarial and analgesic activities.

Materials and methods

The crude leaf extract (220–659 mg/kg) and fractions (chloroform and aqueous; 440 mg/kg) of Acalypha wilkensiana were investigated for antiplasmodial activity against chloroquine sensitive Plasmodium berghei infections in mice and for analgesic activity against chemical and heat-induced pains. The antiplasmodial activity during early and established infections as well as prophylactic activity were investigated. Chloroquine (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. Analgesic activity of the crude extract was also evaluated against acetic acid, formalin and heat-induced pains.

Results

The extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine sensitive Plasmodium berghei infection in prophylactic, suppressive and curative models in mice. These reductions were statistically significant (p < 0.001). They also improved the mean survival time (MST) from 16 to 22 days relative to control (p < 0.01–0.001). The activities of extract/fractions were incomparable to that of the standard drugs used (chloroquine and pyrimethamine). On chemically and thermally induced pains, the extract inhibited acetic acid and formalin-induced inflammation as well as hot plate-induced pain in mice. These inhibitions were statistically significant (p < 0.001) and in a dose-dependent fashion.

Conclusion

The antiparasitaemic and analgesic effects may in part be mediated through the chemical constituents of the plant.     

Mast cell stabilizing effects of Sphaeranthus indicus

Aim of the study

We investigated the effects of Sphaeranthus indicus on mast cell stabilizing activity to provide scientific basis for the clinical use of S. indicus.

Materials and methods

The protective effect of different extracts of whole plant of S. indicus against compound 48/80 and sheep serum induced mast cell degranulation was evaluated.

Results

Ethanol extract of S. indicus at the doses of 150 mg/kg and 300 mg/kg and ethyl acetate extract at the dose of 100 mg/kg, 150 mg/kg and 300 mg/kg showed slightly better protection of mast cell degranulation (77–86%) than the standard drug ketotifen (75%) in the sheep serum model. These extracts also showed better mast cell stabilizing activity (77–88%) than the standard drug (69%) when peritoneal mast cells are treated with compound 48/80.

Conclusion

These results suggest that S. indicus has potent mast cell stabilizing effects thereby inhibiting mediator release from mast cells.     

Anti-stress effect of astragaloside IV in immobilized mice

Ethnopharmacological relevance

Astragaloside IV, a major component extracted from the roots of Astragalus membranaceus (AM), possesses anti-inflammatory, anti-oxidative, anti-fibrotic, anti-infarction and immunoregulatory effects. To clarify anti-stress effect of AM, anxiolytic and anti-inflammatory effects of 80% ethanol extract of AM and astragaloside IV were investigated in immobilization stress model.

Materials and methods

The mice were orally administered with AM (50, 200, and 500 mg/kg), astragaloside IV (5, 10, and 20 mg/kg) and buspirone, a positive drug, 1 h before immobilization treated for 2 h. For anxiolytic activity assay, EPM test was performed in mice. For anti-inflammatory activity assay, serum levels of corticosterone, IL-6 and TNF-α were measured using ELISA kits.

Results

AM extract and astragaloside IV increased dose-dependently time spent on open arms and open arm entries in the EPM test. Anxiolytic effects of AM extract (500 mg/kg) and astragaloside IV (20 mg/kg) were comparable to those of buspirone (1 mg/kg). Their anxiolytic effects were blocked by WAY-100635 (0.5 mg/kg, i.p.), a 5-HT_1A receptor antagonist (p<0.01), but not by flumazenil (3 mg/kg, i.p.) and bicuculline (0.5 mg/kg, i.p.), GABA_A receptor antagonists. AM extract and astragaloside IV also reduced serum levels of corticosterone, IL-6 and TNF-α dose-dependently.

Conclusions

AM, particularly astragaloside IV, may ameliorate immobilized stress-induced anxiety and inflammation.     

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.     

Immunosuppressive activity of ethanolic extract of seeds of Moringa oleifera Lam. in experimental immune inflammation

Ethnopharmacological relevance

Traditionally, the plant Moringa oleifera Lam. (Moringaceae) is used for the treatment of ascites and rheumatism, while the dried seeds of the plant are used as an ‘anti-allergic’ agent.

Aim of the study

The aim of the study was to assess the efficacy of ethanolic extract of seeds from Moringa oleifera Lam. in experimental immune inflammation.

Materials and methods

Circulatory and splenic leukocyte counts, delayed-type hypersensitivity reactions and humoral antibody responses were measured in mice using SRBC as the antigen. In addition, macrophage phagocytosis was measured by the carbon clearance test.

Results

The extract dose-dependently (50, 100 and 200 mg/kg) inhibited spleen weight as well as circulatory leukocyte and splenocyte counts. The delayed-type hypersensitivity reaction was significantly inhibited (P < 0.01) by decreasing the mean foot pad thickness at 48 h. The production of the humoral antibody titer was significantly ameliorated at a dose of 100 and 200 mg/kg (P < 0.05 and P < 0.01, respectively). Furthermore, the extract caused a down-regulation of macrophage phagocytosis due to carbon particles.

Conclusion

Taken together, the above findings suggest that the seeds of Moringa oleifera have immunosuppressive activity.