Neuropharmacological effect of the aqueous extract of Sphaeranthus senegalensis in mice

Effects of the aqueous extract of Sphaeranthus senegalensis Vaill. (Family: Compositae) were studied on spontaneous motor activity, exploratory behaviour, rota-rod performance and pentobarbital sleeping time in mice. Preliminary phytochemical evaluation and acute toxicity (LD(50)) values were also studied. The extract (50 and 100 mg/kg p.o.) produced reduction in spontaneous motor activity, exploratory behaviour and motor coordination and prolonged pentobarbital sleeping time. Glycosides, saponins and tannins were shown to be present in the extract. The i.p. LD(50) in mice was 2735.61 and 5000 mg/kg orally. The results suggest that the aqueous extract of S. senegalensis contains some active principles, which may be sedative in nature.     

Pharmacological activities investigation of crude extracts and fractions from Qualea grandiflora Mart

This study investigates pharmacological activities of crude hydroalcoholic extract and fractions of Qualea grandiflora Mart. leaves employing different experimental models using mice. The treatment with crude hydroalcoholic extract (EH) in a dose of 500 mg/kg, i.p. caused: signs of central nervous system depressant action in the Hippocratic screening test, confirmed by the potentiation of sodium pentobarbital sleeping time. Increasing in the latency time of hot plate assay that indicate an analgesic effect; significantly delaying of the onset of clonic PTZ convulsions, increasing in the time for death, suppressing of the tonic PTZ convulsion, and decreasing of severity and number of convulsions. The median lethal dose of EH was 1.321 mg/kg. The convulsions induced by PTZ, ethyl ether fraction (300 mg/kg, i.p.) was more active in increasing the latency time for first convulsion, moreover, the hexane fraction, at the same dose, was more active in increasing the time for death and/or avoiding the death. Both did not cause disturbance in motor coordination at the dose of 500 mg/kg, assessed by rotarod test. These results suggest that the crude extract of leaves of Qualea grandiflora Mart. has a central nervous system depressant action, an analgesic effect and behave as a potential anticonvulsant.     

The juice of fresh leaves of Boerhaavia diffusa L. (Nyctaginaceae) markedly reduces pain in mice

The decoction or juice of leaves of Boerhaavia diffusa L. (Nyctaginaceae) is used in Martinican folk medicine for its analgesic and anti-inflammatory properties. In the present investigation we studied the acute oral (p.o.) toxicity of a crude extract obtained from a lyophilized decoction (DE) and from the juice (JE) of fresh leaves. We observed no signs of toxicity up to the dose of 5000 mg/kg (p.o.) in mice. At the dose of 1000 mg/kg, neither extract altered sleeping time evoked by the administration of pentobarbital sodium (i.p.). The DE and JE of B. diffusa were assessed in standard rodent models of algesia and inflammation. We investigated the antinociceptive effect of DE and JE in chemical (acetic acid) and thermal (hot plate) models of hyperalgesia in mice. Dipyrone sodium (200 mg/kg), JE (1000 mg/kg) and DE at the same dose (p.o.), produced a significant inhibition of acetic acid-induced abdominal writhing in mice (100, 50 and 47% inhibition, respectively) when compared with the negative control (P<0.001). In the hot-plate test in mice, morphine and JE produced a significant increase in latency during the observation time. The DE, however, only raised the pain thresholds during the first period (30 min) of observation (P<0.05). The extracts of B. diffusa were also investigated for their anti-edematogenic effect on carrageenan-induced edema in mice. However, neither extract inhibited the paw edema induced in mice (P>0.05). In the acetic acid-induced abdominal writhing in mice, pre-treatment of the animals with naloxone (5 mg/kg, i.p.) significantly reversed the analgesic effect of morphine and JE but not that of DE. These data show that the active antinociceptive principle of B. diffusa is present mainly in the juice of fresh leaves and has a significant antinociceptive effect when assessed in these pain models. The mechanism underlying this analgesic effect of fresh leaves of B. diffusa remains unknown, but seems to be related to interaction with the opioid system.     

Pharmacological studies of the aqueous extract of Sapindus trifoliatus on central nervous system: possible antimigraine mechanisms

The aqueous extract of pericarp of fruits of Sapindus trifoliatus (ST) Linn., family Sapindaceae was evaluated for its potential effects on central nervous system in mice. The extract at doses 20 and 100 mg/kg, i.p. significantly (p < 0.001) reduced the spontaneous locomotor activity and at 100 mg/kg, increased the thiopental-induced sleeping time. In rota-rod motor co-ordination test, ST at 100 mg/kg, i.p. significantly (p < 0.05-0.01) reduced the endurance time. Further ST exhibited no protection against maximal electroshock (MES)- and pentylenetetrazole (PTZ)-induced convulsions in mice. In receptor radioligand binding studies, ST exhibited affinity towards dopaminergic, alpha-adrenergic and muscarnic receptors. The findings suggest that, ST may possess principles with potential neuroleptic properties.     

Behavioural effects of Visnea mocanera extract: Psychostimulant and anxiogenic properties

Neuropharmacological studies were conducted in mice with different extracts from the leaves and fruits of Visnea mocanera L. f. (Theaceae). The combined data obtained from all biological models suggest that the methanol extract from the leaves and the syrup from the fruits appear to have a psychostimulant action, since these extracts increased locomotor activity (the methanol extract at 250 mg/kg p.o.), reduced pentobarbital-induced sleeping time (the methanol extract and syrup at 250 mg/kg p.o.) and produced hyperthermia (the syrup at 250 and 500 mg/kg p.o.). The aqueous fraction (250 and 500 mg/kg p.o.) and syrup (500 mg/kg p.o.) from fruits showed an anxiogenic-like profile in mice when evaluated acutely in the elevated plus-maze test.     

Psychopharmacological assessment of Pfaffia glomerata roots (extract BNT-08) in rodents

A pharmacological assessment of the standardized extract (BNT-08) of Pfaffia glomerata roots was performed in young mice submitted to acute treatment with several doses (i.p.), in young and old mice submitted to chronic oral treatment for 150 days or with water (control groups) and in old mice at a dose of 100 mg/kg of extract. Acute tests involved an initial screening, spontaneous movements, rota-rod, barbiturate sleeping time and passive avoidance were carried out. The chronic test involved mortality assessment, body weight and learning and memory in a T-maze left/right discrimination test and in the passive avoidance model. Of the acute tests only the sleeping time test showed relevant differences between the groups. With the chronic treatment, a relevant decrease of the number of sessions necessary for learning in the group of old mice treated with the extract was evident. A partial reversal of the memory de fi cit induced by age in the old mice treated with the extract was found in the passive avoidance test. The results suggest that the standardized extract from Pfaffia glomerata roots promoted an increase in both learning and memory of old mice treated in the chronic test.     

The effects of Icacina trichantha tuber extract on the nervous system

The tuber of Icacina trichantha was extracted with 50% methanol and concentrated to dryness in vacuo to give a yield of 5.6% w/w. The extract induced sleep in rats treated with high doses (400–1000 mg/kg i.p.). The LD₅₀ of the extract was 671 mg/kg i.p. It potentiated pentobarbitone sleeping time in rats dose-dependently and also induced significant local anaesthetic effects in guinea-pigs. The extract was able to give 80% protection to rats poisoned with pentylenetetrazole but failed to protect rats from strychinine poisoning. It induced significant dose-dependent analgesia in rats and showed significant muscle relaxant activity in mice.     

The anxiolytic-like effects of Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) in mice

The aim of the present work is to demonstrate the putative sedative and anxiolytic-like effects of a hydro-ethanolic extract obtained from the aerial parts of Aloysia polystachya (Verbenaceae) in male mice using several behavioural assays. Groups of male mice orally treated with doses of 1.0, 10.0 and 100.0 mg/kg of the extract did not show any significant alteration of their locomotor activity, body temperature or motor coordination. The same treatment increased the duration of the sleeping time induced by 30.0 mg/kg i.p. of sodium pentobarbital. However, the sleeping time induced by ethyl ether was not modified by the oral administration of the extract, not confirming the putative sedative effect of the plant. The ethanolic extract also significantly increased the percentage of both entries (1.0 and 100.0 mg/kg) and the time spent (10.0 and 100.0 mg/kg) into the open arms of the elevated plus maze (EPM). Nevertheless, the binding of (3)H-flunitrazepam ((3)H-FNZ) to the benzodiazepine binding site (BDZ-bs), in washed crude synaptosomal membranes from rat cerebral cortex, was not affected by the semi-purified components from Aloysia polystachya. These results indicate an anxiolytic-like profile of action for the extract of Aloysia polystachya without sedative side effect, being this activity probably mediated by other mechanism than BDZ-bs modulation at the GABA(A) receptors.     

Sedative and anticonvulsant activities of the aqueous root extract of Sanseviera liberica Gerome & Labroy (Agavaceae)

The central nervous system (CNS) depressant and anticonvulsant activities of the aqueous root extract of Sanseviera liberica (ASL) were investigated on various animal models including pentobarbitone sleeping time and hole-board exploratory behaviour for sedation tests, and strychnine, picrotoxin, bicuculline and pentylenetetrazole-induced convulsions in mice. ASL (100-400mg/kg, p.o.), like chlorpromazine HCl (1mg/kg, i.m.), produced a dose-dependent prolongation of pentobarbitone sleeping time and suppression of exploratory behaviour. ASL (100 and 200mg/kg) produced dose-dependent and significant (P<0.05) increases in onset to clonic and tonic convulsions, and at 400mg/kg, showed complete protection against seizures induced by strychnine, picrotoxin and bicuculline, but not with pentylenetetrazole. ASL up to 10 g/kg, p.o. did not produce death, but i.p. treatment produced mortalities with LD(50) of 668.3+/-47.6 mg/kg. Preliminary phytochemical investigations of ASL revealed the presence of carbohydrates, alkaloids, saponins, reducing sugars and oils. The results indicate that ASL has sedative and anticonvulsant activities, therefore, justifying its use in traditional African medicine.     

Psychopharmacological screening of Pfaffia glomerata Spreng. (Amarathanceae) in rodents

The alcoholic extract of Pfaffia glomerata roots (100, 500, 1000 mg/kg, intraperitoneally (i.p.), and 500, 1000, 1500 mg/kg, per os) was studied in several behavioral animal models for the evaluation of central activity: open field, barbiturate sleeping time, pentilenotetrazole (PTZ)-induced convulsions, elevated plus-maze, step-down inhibitory avoidance and forced swimming test. The acute treatment (500 mg/kg, i.p.) interfered with the open-field habituation, decreased sleep latency and increased barbiturate-induced sleeping time, protected partially the animals of PTZ-induced convulsions, decreased the memory retention in step-down inhibitory avoidance, and did not have an important effect in the elevated plus-maze test and forced swimming test. The same extract at 1000 mg/kg per os did not cause any effect in barbiturate sleeping time and pentilenotetrazole-induced convulsions models. Thus, the effect on the memory was deeper evaluated in the step-down inhibitory avoidance task. When administered by intraperitoneal route, the extract showed a dose-dependent effect causing full amnesia at 1000 mg/kg. On the other hand, when it was given by oral route at 500, 1000 and 1500 mg/kg, no influence on the memory retention was observed. These results suggest that the alcoholic extract of P. glomerata roots presents different effects depending on the route of administration: by i.p route, it seems to be a central nervous system depressant agent; by oral route, it seems to be ineffective, at least in the tested doses.     

CNS inhibitory effects of barakol,a constituent of Cassia siamia Lamk

The present study determined the pharmacological profile of barakol, a major constituent of Cassia siamea Lamk., in rodent behavioral and neurochemical tests. Barakol reduced spontaneous locomotor activity, increased the number of sleeping animals and prolonged the thiopental-induced sleeping time, indicating a sedative effect. As for interactions between barakol and convulsants (pentylenetetrazole (PTZ), picrotoxin, bicuculline and strychnine), only a high dose (100 mg/kg, i.p.) of barakol slightly prolonged the latency of clonic convulsion induced by picrotoxin. This suggests that the sedative effect may not be induced via the GABA or glycine systems. There was no evidence of an anxiolytic effect of barakol in the plus-maze test. However, barakol (25-100 mg/kg, i.p.) could suppress methamphetamine (1 mg/kg, i.p.)-induced hyper-locomotor activity in a dose-dependent manner, indicating an effect on the dopaminergic system. In a microdialysis study, the dose of barakol (100 mg/kg) that inhibited spontaneous locomotor activity in mice did not affect the basal levels of extracellular dopamine (DA) or its metabolites in the striatum. However, pretreatment with barakol (100 mg/kg, i.p.) decreased the maximal dopamine release and dopamine turnover induced by methamphetamine (1 mg/kg, i.p.). This finding indicates that the inhibitory effect of barakol on dopamine release may account for the blocking effect of barakol on the striatum-related behavior induced by methamphetamine.     

Antitumour property and toxicity of Barringtonia racemosa Roxb seed extract in mice

Ethnomedical survey has shown that the seeds of Barringtonia racemosa Roxb are traditionally used in certain remote villages of Kerala (India) to treat cancer like diseases. So the seed extracts were tested for their antitumour activity and toxicity. Intraperitoneal (i.p.) daily administration of 50% methanol extract of this seed to mice challenged with 1 million Dalton's Lymphoma Ascitic (DLA) cells resulted in remarkable dose dependent anti-DLA activity in mice. The optimum dose was found to be 6 mg/kg. This dose protected all the animals challenged with the tumour cells. The efficacy of the drug was found to be better than that of a standard drug, vincristine in this tumour model. However, the oral administration showed only marginal activity compared to i.p. administration. The extract was found to be devoid of conspicuous acute and short-term toxicity to mice, when administered daily, (i.p.) for 14 days up to a dose of 12 mg/kg (which was double the concentration of optimum therapeutic dose). The treated mice showed conspicuous toxic symptoms only at 24 mg/kg. The LD(50) to male mice for a single i.p. dose was found to be 36 mg/kg. The seed extract is an attractive material for further studies leading to drug development.     

Synergistic effect of methanol extract of Abies webbiana leaves on sleeping time induced by standard sedatives in mice and anti-inflammatory activity of extracts in rats

During the determination of LD50 values of extracts of Abies webbiana, it was observed that the methanol extract (MEAW) produces sedation of animals. This led to investigation of the effect of MEAW on sleeping time in mice. When various doses of the methanol extract (100, 150, and 200 mg/kg body weight) were administered alone, no hypnotic activity was observed. However, these exhibited significant synergistic effects (P < 0.001) at those dose levels in mice when administered prior to the administration of standard sedatives (pentobarbitone sodium: 50 mg/kg and diazepam: 6 mg/kg, respectively). In addition anti-inflammatory effects of methanol, chloroform, and petroleum ether extracts of Abies webbiana leaves in rats were performed to assess scientific validity of the medicinal claim of Indian folk medicine. The effects of leaf extracts (methanol, chloroform, and petroleum ether) against inflammation were studied by carrageenan-induced paw edema model in rats. The methanol extract (400 mg/kg p.o.) of leaves of Abies webbiana showed the best significant anti-inflammatory activity as compared to that of diclofenac sodium (150 mg/kg p.o.). The LD50 values of methanol, chloroform, and petroleum ether extracts were found to be 986, 1387, and > 3200 mg/kg, respectively. Thus, the therapeutic index of methanol extract may be favorable to open a new vista on combination therapy of hypnotics and may also against inflammation.     

Sedative, antiepileptic and antipsychotic effects of Spondias mombin L. (Anacardiaceae) in mice and rats

In this study, we evaluated the effects of air-dried Spondias mombin leaves extracted with aqueous, methanol and ethanol solvents on hexobarbital-induced sleeping time and novelty-induced rearing (NIR) behaviours in mice and rats. We also studied the effect of the extracts on amphetamine- and apomorphine-induced stereotyped and picrotoxin-induced convulsive behaviour in rats. All residues from different extractions were dissolved in normal saline and administered intraperitoneally (i.p.). The methanolic and ethanolic extracts (12.5-100mg/kg i.p.) prolonged the hexobarbital-induced sleeping time and reduced the NIR in both mice and rat in a dose-dependent manner. The aqueous extract prolonged the hexobarbital-induced sleeping time and reduced (NIR) at doses of 50 and 100mg/kg. The inhibitory effect of the extracts on NIR was not reversed by atropine, yohimbine, naltrexone and flumazenil. However, the extracts blocked the facilitating effect of flumazenil. This suggests that NIR inhibitory effects of extracts of Spondia mombin are not mediated via muscarinic, alpha(2) adrenergic, and mu-opioid receptors, whereas, the extracts appear to facilitate GABAergic transmission. In addition the extracts blocked picrotoxin-induced convulsions. Phenolic compound(s) were present in the ethanolic and methanolic extracts, which exhibited anticonvulsant properties in the picrotoxin-induced convulsions model. The extracts decreased the amphetamine/apomorphine-induced stereotyped behaviour, which suggest that these extracts possess antidopaminergic activity. The effect of the extracts on hexobarbitone-induced sleeping time was blocked by flumazenil a GABA(A) antagonist, indicating that the extracts contain GABA(A) agonists. These results suggest that the leaves extracts of Spondias mombin possess sedative and antidopaminergic effects.     

Anticonvulsant properties of the methanolic extract of Cyperus articulatus (Cyperaceae)

The methanolic extract of rhizomes of Cyperus articulatus, a plant used in traditional medicine in Africa and Latin America for many diseases, possesses anticonvulsant activity in mice. This extract protected mice against maximal electroshock (MES)- and pentylenetetrazol (PTZ)-induced seizures. It also delayed the onset of seizures induced by isonicotinic acid hydrazide and strongly antagonized N-methyl-D-aspartate-induced turning behavior. The ED(50) for protection against seizures was 306 (154-541) mg/kg intraperitoneally (i.p.) for the PTZ test and 1005 (797-1200) mg/kg i.p. for the MES test. The ED(50) of methanolic extract against N-methyl-D-aspartate-induced turning behavior was 875 (623-1123) mg/kg i.p. C. articulatus L. methanolic extract protected 54% of mice from seizures induced by strychnine at the dose of 1000 mg/kg i.p. but had no or a moderate effect only against picrotoxin- or bicuculline-induced seizures. With these effects, the rhizome of C. articulatus L. possesses anticonvulsant properties in animals that might explain its use as a traditional medicine for epilepsy in Africa.     

Antidepressant effects of the methanol extract of several Hypericum species from the Canary Islands.

The aim of the present study was to investigate several neuropharmacological effects of the methanol extract of the aerial parts in blossom of Hypericum canariense, H. glandulosum, H. grandifolium and H. reflexum (Hypericaceae). These extracts did not alter significantly the locomotor activity, body temperature or the pentobarbital-induced sleeping time, with the exception of H. reflexum which significantly potentiated pentobarbital-induced sleeping time at both doses assayed (500 and 1000 mg/kg p.o.). Additionally, neither muscle relaxant nor anticholinergic activity was observed. These extracts antagonized the ptosis and/or motor depression induced by tetrabenazine and also shortened the immobility time in the forced swimming test. Moreover, the H. glandulosum and H. grandifolium extracts at 1000 mg/kg p.o. potentiated the head twitches induced by 5-HTP. These observations suggest that the methanol extract of the Hypericum species in doses of 500-1000 mg/kg p.o. possess antidepressant activity in mice, without inducing significant muscle relaxation, anticholinergic and sedative properties.     

Neuropharmacological screening of Diospyros mespiliformis in mice

The neuropharmacological activities of the aqueous extract of Diospyros mespiliformis stem bark were screened in mice. The extracts effect on pentobarbital-induced sleeping time, pentylenetetrazole induced seizure, spontaneous motor activity (SMA), exploratory behaviour, and rota-rod performance (motor coordination) were evaluated. The extract (100 and 200 mg/kg p.o.) produced a significant (P<0.05) prolongation of pentobarbital-induced sleeping time, and reduced the SMA and exploratory behaviour. The extract prolonged onset of the phases of seizure activity but did not protect mice against lethality induced by pentylenetetrazole. It also failed to affect the motor coordination test. These results suggest that the extract contained an agent with neuropharmacological activity that may be sedative in nature.     

Analgesic and antiinflammatory properties of Scoparia dulcis L. Extracts and glutinol in rodents

The analgesic, antiinflammatory and antipyretic activities of the water (WE) and ethanolic (EE) extracts of Scoparia dulcis L. were tested in mice and rats. Both extracts (0.5 and 1 g/kg) p.o., prolonged the sleeping time induced by pentobarbital in mice, EE being more active than WE. Injections of EE (0.5–2 mg/kg i.v.) to anaesthetized rats induced a dose-related hypertension inhibited by alpha-blocker drugs; the hypertension was not obtained after oral treatment. EE (0.25-1 g/kg p.o.) but not WE, reduced writhings induced by acetic acid in mice. Glutinol (30 mg/kg p.o.), a major triterpene obtained from EE, produced the same effect. The tail flick response of mice was not influenced by either extract. EE (0.5 and 1 g/kg) and glutinol (30 mg/kg) p.o., reduced the paw oedema and pleurisy induced by carrageenin in rats, but only EE (1 g/kg) reduced the paw oedema induced by dextran or histamine. No effect of EE was detected on chronic inflammation induced by cotton pellets and in yeast-induced hyperthermia in rats. The results indicate that the extract of S. dulcis is endowed with analgesic effects probably related to the antiinflammatory activity of the plant. Those effects are related mainly to the presence of glutinol and flavonoids, which exert their action on the early phase of the acute inflammatory process.     

异叶败酱挥发油镇静作用的研究

本文观察了败酱科植物异叶败酱根和根茎中制得的挥发油的镇静和安眠作用。结果表明,此油灌胃给予数组小鼠,剂量0.25ml/kg,显示如下的作用:(1)显著延长由于腹腔注射戊巴比妥钠40mg/kg 引起的睡眠时间,其强度与黄花败酱挥发油基本相同。(2)显著增加由腹腔注射戊巴比妥钠阈下剂量(25mg/kg)引起的阳性反应率。(3)显著增加小鼠肝匀浆中细胞色素P-450的含量。上述结果表明,异叶败酱挥发油具有中枢性镇静作用。一次灌胃给予小鼠大剂量(5.0ml/kg)的异叶败酱挥发油,连续观察6天。动物无一死亡,外观正常,仅体重增加较少。     

Skeletal muscle relaxant action of an aqueous extract of Portulaca oleracea in the rat

The aqueous extract of Portulaca oleracea produced skeletal muscle relaxation in rats following i.p. or oral administration, as assessed by the prolongation of pull-up time. The i.p. route of administration was more effective. When compared with chlordiazepoxide (20 mg/kg, i.p.), diazepam (40 mg/kg, i.p.) and dantrolene sodium (30 mg/kg, oral), the extract (200-1000 mg/kg, i.p.) proved a more effective skeletal muscle relaxant. With 1000 mg/kg i.p., 80% lethality was seen. The LD50 in an acute toxicity test in mice was 1040 mg/kg i.p.