Acute effects of bergamot oil on anxiety-related behaviour and corticosterone level in rats

Bergamot essential oil (BEO), Citrus aurantium subsp. bergamia (Risso) Wright & Arn. (Rutaceae), is used widely in aromatherapy to reduce stress and anxiety despite limited scientific evidence. A previous study showed that BEO significantly increased gamma-aminobutyric acid levels in rat hippocampus, suggesting potential anxiolytic properties. The aim of this study was to investigate the effect of BEO (1.0%, 2.5% and 5.0% w/w) administered to rats on both anxiety-related behaviours (the elevated plus-maze (EPM) and hole-board tests) and stress-induced levels of plasma corticosterone in comparison with the effects of diazepam. Inhalation of BEO (1% and 2.5%) and injection of diazepam (1 mg/kg, i.p.) significantly increased the percentage of open arm entries on the EPM. The percentage time spent in the open arms was also significantly enhanced following administration of either BEO (2.5% and 5%) or diazepam. Total arm entries were significantly increased with the highest dose (5%), suggesting an increase in locomotor activity. In the hole-board test, 2.5% BEO and diazepam significantly increased the number of head dips. 2.5% BEO and diazepam attenuated the corticosterone response to acute stress caused by exposure to the EPM. In conclusion, both BEO and diazepam exhibited anxiolytic-like behaviours and attenuated HPA axis activity by reducing the corticosterone response to stress.     

Postnatal development and reproductive performance of F1 progeny exposed in utero to an ayurvedic contraceptive: Pippaliyadi yoga

The purpose of this study was to characterize the putative anxiolytic-like activity of an ethanolic extract prepared from the leaves of Apocynum venetum (AV) using the elevated plus maze (EPM) in mice. Male C75BL/6 mice were either treated orally with the AV extract or the positive controls diazepam and buspirone, respectively, 1 h before behavioral evaluation in the EPM. A single treatment of AV extract markedly increased the percentage time spent on and the number of entries into the open arms of the EPM in doses of 30 and 125 mg/kg p.o., respectively. This effect was comparable to that of the benzodiazepine diazepam (1.5 mg/kg p.o.) and the 5-HT_1A agonist buspirone (10 mg/kg p.o.). The effects of AV in 125 mg/kg were effectively antagonized by the benzodiazepine antagonist flumazenil (3 mg/kg i.p.). However, the effects of AV extract could only partially be blocked by the unspecific 5-HT_1A receptor antagonist WAY-100635 (0.5 mg/kg i.p.). Neither diazepam and buspirone nor the AV extract produced any overt behavioral change or motor dysfunction in the open field test. These results indicate that AV extract is an effective anxiolytic agent, and suggest that the anxiolytic-like activities of this plant are mainly mediated via the GABAergic system.     

Anxiolytic effect of seed of Ziziphus jujuba in mouse models of anxiety

The aim of the present study was to investigate the ethanolic extract of Semen Ziziphi jujuba (SZJE) induced anxiolytic effect. The SZJE was orally administered to male ICR mice, at 0.5, 1.0 and 2. 0 g/kg, 30 min before the behavioral evaluation in the black and white test (BWT) and elevated plus maze (EPM). The SZJE at the dosage 0.5-2.0 g/kg increased the first time entry, total changes and times spent in the white chamber of the BWT. The SZJE at the dosage 0.5-1.0 g/kg increased the percentage of time-spent and the percentage of arm entries in the open arms of the EPM and decreased the percentage of time-spent and the percentage of arm entries in the closed arms of the EPM. Furthermore, the SZJE at the dosage of 1. 0 g/kg prolonged the hexobarbital-induced sleeping time in mice and decreased the locomotor activity in rats. These results suggested that SZJE possessed anxiolytic effect at lower dose and sedative effect at higher dose.     

Neurosedative and muscle-relaxant activities of ethyl acetate extract of Baphia nitida AFZEL

The sedative, anxiolytic and muscle-relaxant effects of the ethyl acetate leaf extract of Baphia nitida (BN) was investigated in intact mice, using the hole-board head-dip test for exploratory behavioural effect, elevated plus maze (EPM) and Y-maze (YM) models of anxiety; chimney, inclined screen, traction and climbing tests for muscle-relaxant effects. In each of these tests, BN (100-400mg/kg, p.o.), diazepam (1mg/kg, i.p.) or distilled water (10ml/kg, p.o.) was administered, 30 or 60min before performing the tests in mice. For exploratory behavioural test, number of head-dip within 15min was counted. For EPM and YM tests, the cumulative time spent in open and closed arms was recorded within 5min. In the muscle-relaxant tests, mice were subjected to modified models such as chimney, inclined screen, traction and climbing tests. BN produced a significant (P<0.05) dose-related decrease in exploratory behaviour in the head-dip test and prolongation of cumulative time spent in open arms of both EPM and YM. BN did not show any significant effect in the chimney and traction tests, but produced significant, dose-dependent muscle relaxation in the inclined screen and climbing tests. Furthermore, BN (200-1200microg/ml) non-competitively shifted the curves of acetylcholine contractions of the toad Rectus abdominis muscle to the right. Oral doses of BN (0.1-20g/kg) did not produce mortality, but the LD(50) when given intraperitoneally, was 645.65mg/kg. Results suggest that the leaf extract of Baphia nitida has sedative, anxiolytic and skeletal muscle-relaxant effects and support its neurosedative use in traditional African medicine.     

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.     

Anxiolytic effects of Stachys lavandulifolia Vahl on the elevated plus-maze model of anxiety in mice

Interest in alternative medicine and plant-derived medications that affect the "mind" is growing. The aim of the present study was to investigate the effects of a hydroalcoholic extract and essential oil of Stachys lavanduifolia Vahl on the elevated plus-maze (EPM) model of anxiety. The Stachys lavandulifolia extract or its essential oil was administered intraperitoneally to male TO mice, at various doses, 30 min before the behavioral evaluation. The extract of Stachys lavandulifolia at the dose of 100 mg/kg increased the percentage of time spent and the percentage of arm entries in the open arms of the EPM and decreased the percentage of time spent and the percentage of arm entries in the closed arms of the EPM. The plant extract at doses lower than 100 mg/kg had no significant effects on any of the parameters measured on the EPM. This dose of the plant extract prolonged the ketamine-induced sleeping time, and decreased the locomotor activity in mice. These results suggested that the extract of Stachys lavandulifolia possessed anxiolytic effect with relatively lower sedative activity than diazepam. The essential oil of Stachys lavandulifolia, however, at doses of up to 100 mg/kg did not have any significant effects on the mice behaviour on the EPM.     

Anxiolytic effects of fractions obtained from Passiflora incarnata L. in the elevated plus maze in mice

The purpose of this study was to characterize the putative anxiolytic-like activity of fractions prepared from a hydroethanol extract of Passiflora incarnata L. using the elevated plus-maze (EPM) in mice. The fractions were prepared as published recently, yielding a butanol, petroleum ether and chloroform fraction. From the tested fractions, the butanol fraction showed significant increases in the number of open arm entries in the EPM in concentrations of 2.1 mg/kg and 4.2 mg/kg corresponding to 150 and 300 mg/kg of the original extract. The highest activity was found for the chloroform fraction in doses of 0.17 mg/kg (10.0 ± 1.9, p < 0.001) and 0.34 mg/kg (6.6 ± 0.86; p < 0.05) which corresponds to a total extract dose of 150 and 300 mg/kg, respectively. Interestingly, the petroleum ether fraction did not show any effects in the elevated plus maze. A sedative or stimulatory effect of each of the fractions could be excluded, since none of the compounds had an influence on the total distance that the animals covered during the observation period. The results suggest that the active principle of passion flower seems to be in the chloroform fraction and to a lower extent in the butanol fraction.     

Anxiolytic effects of Salvia reuterana Boiss. on the elevated plus-maze model of anxiety in mice

The anxiolytic and sedative effects of hydroalcoholic extract (HE) of Salvia reuterana Boiss. was evaluated in mice. The HE of Salvia reuterana (100 mg/kg), increased the percentage of time-spent and the percentage of arm entries in the open arms of the elevated plus-maze. Spontaneous locomotor activity count measured in 15 min of the test was significantly decreased in animals pretreated with diazepam and 100 mg/kg of Salvia reuterana extract. Results of the present study provide support for the traditional usage of Salvia reuterana as a sedative and anxiolytic medicinal plant.     

Anxiolytic effect of saponins from Panax quinquefolium in mice

The anxiolytic effect of the saponins from Aniliaeea Panax quinquefolium L. (PQS) was studied in male mice by using a number of experimental paradigms of anxiety and compared with that of the known anxiolytic compound diazepam. Use of the elevated plus-maze test revealed that PQS (50 mg/kg, p.o.) and diazepam (2.5 mg/kg, p.o.) increased the percentage of time and entries spent in open arms. In the light/dark test, PQS (50 and 100 mg/kg, p.o.) and diazepam (2.5 mg/kg, p.o.) prolonged the time spent in the light area. In the hole-board test, PQS (50 and 100 mg/kg, p.o.) and diazepam (2.5 mg/kg, p.o.) significantly increased both head-dip counts and head-dip duration. Both PQS (50 and 100 mg/kg, p.o.) and diazepam (2.5 mg/kg, p.o.) decreased the total fighting time in the isolation-induced aggressive test. Since PQS, in contrast to diazepam, had no effect on locomotion in these tests, its side-effect profile might be considered superior to the benzodiazepines. Thus, the present findings suggest that PQS might be a potential candidate for use as an anxiolytic drug.     

Hydroalcohol extract and fractions of Stachys lavandulifolia Vahl: effects on spontaneous motor activity and elevated plus-maze behaviour

The present study aimed to investigate the anxiolytic effects of four fractions of Stachys lavandulifolia Vahl. The aerial parts of the plant were extracted with petroleum ether (PF), ethyl acetate (EF), butanol (BF) and water (AF) and tested for spontaneous motor activity and elevated plus-maze (EPM) behaviour in mice. The hydroalcohol extract (HE) and different fractions of S. lavandulifolia were administered intraperitoneally to male Syrian mice, at various doses, 30 min before the behavioural evaluation. The HE of S. lavandulifolia (at 50 mg/kg) increased the percentage of time spent (39%) and the percentage of arm entries in the open arms (53%). The HE (50 mg/kg), PF (25 and 50 mg/kg), EF (25 and 50 mg/kg) and AF (50 mg/kg) of S. lavandulifolia significantly increased the percentage of time spent and the percentage of arm entries in the open arms. The BF up to a dose of 50 mg/kg had no significant effects on any of the measured parameters in the EPM. The spontaneous locomotor activity was significantly decreased in animals injected with each plant fractions, compared with that of saline. The EF and AF showed the least and the most reduction in the activity, respectively. The anxiolytic effects of EF, PF and AF could be related to their content of flavonoids, phenylpropanoids or terpenoids.     

Evaluation of the analgesic, anti-inflammatory and anti-diabetic properties of Sclerocarya birrea (A. Rich.) Hochst. stem-bark aqueous extract in mice and rats

In order to appraise some of the ethnomedical uses of Sclerocarya birrea (A. Rich.) Hochst., subspecies caffra (Sond.) Kokwaro [family: Anacardiaceae], the present study was undertaken to investigate the analgesic, anti-inflammatory and anti-diabetic properties of the plant's stem-bark aqueous extract in experimental models of pain, inflammation and diabetes mellitus. The analgesic effect of Sclerocarya birrea stem-bark aqueous extract was evaluated in mice, while its anti-inflammatory and anti-diabetic effects were investigated in rats. Diclofenac (DIC, 100 mg/kg p. o.) and chlorpropamide (250 mg/kg p. o.) were used respectively as reference analgesic, anti-inflammatory and anti-diabetic agents for comparison. Like diclofenac (DIC, 100 mg/kg p. o.), Sclerocarya birrea stem-bark aqueous extract (SBE, 100-800 mg/kg p. o.) produced dose-dependent, significant protection (p < 0.05-0.001) against electrical heat-induced pain. The plant extract (SBE, 25-800 mg/kg p. o.) also produced dose- and time-related, sustained and significant reductions (p < 0.05-0.001) in the fresh egg albumin-induced acute inflammation of the rat hind paw oedema. However, the analgesic and anti-inflammatory effects of the plant's extract were found to be approximately 10-15 times less than that of diclofenac. In one set of experiments involving hypoglycaemic/antidiabetic evaluation of the plant's extract, graded doses of Sclerocarya birrea stem-bark aqueous extract (SBE, 25-800 mg/kg p. o.) were separately administered to groups of fasted normal and fasted diabetic rats. In another set of experiments, a single dose of the plant's aqueous extract (SBE, 800 mg/kg p. o.) was used. The hypoglycaemic effect of this single dose of Sclerocarya birrea stem-bark aqueous extract (SBE, 800 mg/kg p. o.) was compared with that of chlorpropamide (250 mg/kg p. o.) in both fasted normal and fasted streptozotocin (STZ)-treated diabetic rats. Following acute treatment, relatively moderate to high doses of Sclerocarya birrea stem-bark aqueous extract (SBE, 25-800 mg/kg p. o.) produced dose-dependent, significant reductions (p < 0.05-0.001) in the blood glucose concentrations of both fasted normal and fasted diabetic rats. Chlorpropamide (250 mg/kg p. o.) also produced significant reductions (p < 0.05-0.001) in the blood glucose concentrations of the fasted normal and fasted diabetic rats. Administration of the single dose of Sclerocarya birrea stem-bark aqueous extract (SBE, 800 mg/kg p. o.) significantly reduced (p < 0.01-0.001) the blood glucose levels of both fasted normal (normoglycaemic) and fasted STZ-treated, diabetic rats. The results of this experimental animal study indicate that Sclerocarya birrea stem-bark aqueous extract possesses analgesic, anti-inflammatory and hypoglycaemic properties. These experimental findings lend pharmacological support to the suggested folkloric uses of the plant's stem-bark in the management and/or control of pain, inflammatory conditions, and adult-onset, type-2 diabetes mellitus in some communities of South Africa.     

Anxiolytic effect of ting-chih-wan in mouse behavior models of anxiety

The anxiolytic effect of the alcoholic extract of ting-chih-wan (TCWa) was studied using the black and white test (BWT) and the elevated plus-maze (EPM). We further demonstrated the anxiolytic mechanism of TCWa by combining with diazepam (DIZ), serotonin (5-HT) agonists or antagonists, and measuring the levels of monoamines and its metabolites in the brain stem and cortex. In the BWT, TCWa (0.1-1.0 g/kg, p.o.) increased the time spent in the white chamber and total change between the two chambers, and decreased the time spent in the black chamber. TCWa (0.1-0.5 g/kg, p.o.) increased the arm entries and the time spent on the open arms, and decreased the arm entries and the time spent on the closed arms in the EPM. On the other hand, TCWa (1.0 g/kg, p.o.) decreased horizontal activity and prolonged pentobarbital-induced sleeping times. TCWa (0.1, 0.5 g/kg) decreased the levels of norepinephrine (NE), dopamine (DA), 5-HT and 5-hydroxy-indoleacetic acid (5-HIAA) and increased the levels of vanillylmandelic acid (VMA) and homovanillic acid (HVA) in the brain stem. TCWa (0.1 and 0.5 g/kg) decreased the levels of NE, DA and increased the levels of VMA and HVA in the cortex. TCWa also attenuated the anxiogenic effect of 5-hydroxytryptophan (5-HTP) and enhanced the anxiolytic effect of 9p-chlorophenylalanine (PCPA), buspirone (BUS) and ritanserin (RIT) in the EPM. From these results, TCWa at 0.1 and 0.5 g/kg possessed an anxiolytic effect T heanxiolytic mechanisms of TCWa might be due to decreased catecholaminergic activity caused by the increase in the turnover rate of catecholamines in the brain and decreased concentrations of 5-HT in the brain stemvia activating somatodendritic 5-HT1A autoreceptors and inhibiting postsynaptic 5-HT receptors.     

Central nervous system activity of the hydroalcoholic extract of Casimiroa edulis in rats and mice

In order to evaluate the effects produced by the hydroalcoholic extract of leaves from Casimiroa edulis on the central nervous system, different behavioral tests and animal models of depression and anxiety were performed. The extract was administered intraperitoneally in male and female rats and tested on spontaneous motor activity, locomotor activity, exploration of an elevated plus-maze (EPM) and in the forced swimming test (FST). In addition, the extract was administered orally in male and female mice and evaluated in the following tests: general observation, pentobarbital-induced hypnosis, EPM, rota-rod, hole-board, and marble-burying. The results revealed that, in rats, the extract caused considerable reduction of locomotor and exploratory activities and increased the exploration of the EPM open arms in a similar way that diazepam. In the FST, the extract was as effective as fluoxetine in inducing shortening of immobility, along with a significant increase on climbing duration. On the other hand, in mice, the extract prolonged pentobarbital-induced hypnosis, increased exploration of the EPM open arms and partially protected from the pentylenetetrazol-induced convulsions. No significant effect was evident on motor coordination, hole-board and marble-burying tests. These results suggest that the hydroalcoholic extract of Casimiroa edulis may contain sedative principles with potential anxiolytic and antidepressant properties, which need further investigation.     

Coriandrum sativum: evaluation of its anxiolytic effect in the elevated plus-maze

The clinical applications of benzodiazepines as anxiolytics are limited by their unwanted side effects. Therefore, the development of new pharmacological agents is well justified. Among medicinal plants, Coriandrum sativum L. has been recommended for relief of anxiety and insomnia in Iranian folk medicine. Nevertheless, no pharmacological studies have thus far evaluated its effects on central nervous system. Therefore, the aim of this study was to examine if the aqueous extract of Coriandrum sativum seed has anxiolytic effect in mice. Additionally, its effect on spontaneous activity and neuromuscular coordination were evaluated. The anxiolytic effect of aqueous extract (10, 25, 50, 100 mg/kg, i.p.) was examined in male albino mice using elevated plus-maze as an animal model of anxiety. The effects of the extract on spontaneous activity and neuromuscular coordination were assessed using Animex Activity Meter and rotarod, respectively. In the elevated plus-maze, aqueous extract at 100 mg/kg showed an anxiolytic effect by increasing the time spent on open arms and the percentage of open arm entries, compared to control group. Aqueous extract at 50, 100 and 500 mg/kg significantly reduced spontaneous activity and neuromuscular coordination, compared to control group. These results suggest that the aqueous extract of Coriandrum sativum seed has anxiolytic effect and may have potential sedative and muscle relaxant effects.     

Anxiolytic effect of Rubus brasilensis in rats and mice

The aim of the present work was to investigate if infuse and ethanolic extracts (aqueous, butanolic and wax fractions) of Rubus brasiliensis Martius (Rosaceae) induce anxiolytic effect. The extracts were administered to male Wistar rats and Swiss mice per oral route, at 50, 100 and 150 mg/kg, 30 min before the behavioral evaluation in the elevated plus maze (EPM). Both infuse and wax ethanolic fraction at the dosage 150 mg/kg, vo, increased the number and the percentage of open arm entries of rats and mice. The aqueous and butanolic fractions, obtained from ethanolic extract, failed to induce anxiolytic effect. The treatment of mice with flumazenil (Ro 15–1788), 1.5, 2.0 and 2.5 mg/kg, i.p., 15-min before the administration of infuse or wax fraction, 150 mg/kg, vo, blocked the infuse or wax fraction-induced anxiolytic effect. The LD₅₀ for the wax fraction was 1000 mg/kg. In conclusion, the infuse and wax ethanolic fraction of R. brasiliensis present anxiolytic effect in rats and mice. In addition, it is suggested that the anxiolytic effect may be attributed at least to one liposoluble principle with low acute toxicity which may be acting as an agonist on GABA_A-benzodiazepine receptor complex.     

Study of the hypoglycaemic activity of Lepidium sativum L. aqueous extract in normal and diabetic rats

The hypoglycaemic effect of an aqueous extract of Lepidium sativum L. (LS) seeds was investigated in normal and streptozotocin (STZ)-induced diabetic rats. After a acute (single dose) or chronic (15 daily repeated administration) oral treatments, the aqueous LS extract (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats (p < 0.001); the blood glucose levels were normalised 2 weeks after daily repeated oral administration of aqueous LS extract (20 mg/kg) (p < 0.001). Significant reduction on blood glucose levels were noticed in normal rats after both acute (p < 0.01) and chronic treatment (p < 0.001). In addition, no changes were observed in basal plasma insulin concentrations after treatment either in normal or STZ diabetic rats indicating that the underlying mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that the aqueous extract of LS exhibits a potent hypoglycaemic activity in rats without affecting basal plasma insulin concentrations.     

Anxiolytic-like actions of leaves of Casimiroa edulis (Rutaceae) in male Wistar rats

Anxiolytic-like actions of an aqueous extract of the leaves of Casimiroa edulis (Ce) La Llave ex Lex. (Rutaceae) were studied in male Wistar rats in the elevated plus-maze test, whether effect on locomotion were studied in the open-field task, and its possible antidepressant-like actions in the forced swimming task. In the elevated plus-maze test, diazepam (Dz) (1.30 mg/kg; P < 0.05) and Casimiroa edulis (25.0 mg/kg, P < 0.05; 35.0 mg/kg, P < 0.05) increased open arms exploration (i.e., anxiolytic-like action). Doses of 45.0 mg/kg (P < 0.05) and 55.0 mg/kg (P < 0.05) of Casimiroa edulis reduced locomotion in the elevated plus-maze test and in the open-field test. In the forced swimming task, desipramine (dmi) (32.0 mg/kg; P < 0.05) reduced immobility (i.e., antidepressant-like action). Conversely, as compared to control rats, neither diazepam (Dz) (1.30 mg/kg) nor Casimiroa edulis (25.0 mg/kg) modified immobility in the forced swimming task. However, diazepam (P < 0.05) or Casimiroa edulis (P < 0.05), when co-administered, canceled the antiimmobility actions of desipramine. In conclusion, the leaves of Casimiroa edulis (Rutaceae) produced anxiolytic-like actions in male Wistar rats, with several side actions, namely, reduced locomotion and neutralization of the antidepressant-like actions of desipramine.     

三种一般钩藤ITS序列的RFLP分析

目的以核糖体转录间隔区(rDNA ITS)序列为分子标记,对采集自3个不同地区的一般钩藤Uncaria rhynchophylla(Miq.)Jack.进行RFLP遗传分析,研究不同地理区域一般钩藤的rDNA ITS序列是否具有生物地理差异。方法通过改良CTAB法提取一般钩藤总DNA,利用通用引物对其rDNA ITS序列进行PCR扩增,并对连接转化后扩增得到的rDNAITS序列进行限制性片段长度多态性(Restriction Fragment Length Polymorphism,RFLP)分析。结果获得采集自广东韶关阳山、广东梅州大埔、广西植物园的3种一般钩藤两种限制性内切酶(Msp I&HaeⅢ)酶切图谱。结论通过基于rDNAITS序列进行的RFLP分析,表明这3个地区的一般钩藤rDNA ITS序列无明显差异,不同区域的一般钩藤其遗传本质不具有地理差异。     

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.     

Anticonvulsant effect of Uncaria rhynchophylla (Miq) Jack. in rats with kainic acid-induced epileptic seizure.

This study investigated the anticonvulsant effect of Uncaria rhynchophylla (UR) and the physiological mechanisms of its action in rats. A total of 70 male Sprague-Dawley (SD) rats were selected for study. Thirty four of these rats were divided into 5 groups as follows: 1) Control group (n = 6): received intraperitoneal injection (i.p.) of kainic acid (KA, 12 mg/kg); 2) UR1000 group (n = 10), 3) UR500 group (n = 6) 4) UR250 group, received UR 1000, 500, 250 mg/kg i.p. 30 min prior to KA administration, respectively; 5) Contrast group: received carbamazepine 20 mg/kg i.p. 30 min prior to KA administration. Behavior and EEG were monitored from 15 min prior to drug administration to 3 hours after KA administration. The number of wet dog shakes were counted at 10 min intervals throughout the experimental course. The remaining 36 rats were used to measure the lipid peroxide level in the cerebral cortex one hour after KA administration. These rats were divided into 6 groups of 6 rats as follows: 1) Normal group: no treatment was given; 2) Control group: received KA (12 mg/kg) i.p.; 3) UR1000 group, 4) UR500 group, 5) UR250 group, received UR 1000, 500, 250 mg/kg i.p. 30 min prior to KA administration, respectively; 6) Contrast group: received carbamazepine 20 mg/kg i.p. 30 min prior to KA administration. Our results indicated that both UR 1000 and 500 mg/kg decreased the incidence of KA-induced wet dog shakes, no similar effect was observed in the UR 250 mg/kg and carbamazepine 20 mg/kg group. Treatment with UR 1000 mg/kg, 500 mg/kg, or 250 mg/kg and carbamazepine 20 mg/kg decreased KA-induced lipid peroxide level in the cerebral cortex and was dose-dependent. These findings suggest that the anticonvulsant effect of UR possibly results from its suppressive effect on lipid peroxidation in the brain.