Efficacy study of Prunus amygdalus (almond) nuts in scopolamine-induced amnesia in rats.

OBJECTIVE: Cognitive disorders such as amnesia, attention deficit and Alzheimer's disease are emerging nightmares in the field of medicine because no exact cure exists for them, as existing nootropic agents (piractam, tacrine, metrifonate) have several limitations. The present study was undertaken to investigate the effect of Prunus amygdalus (PA) nuts on cognitive functions, total cholesterol levels and cholinesterase (ChE) activity in scopolamine-induced amnesia in rats. MATERIALS AND METHODS: The paste of PA nuts was administered orally at three doses (150, 300 and 600 mg/kg) for 7 and 14 consecutive days to the respective groups of rats. Piracetam (200 mg/kg) was used as a standard nootropic agent. Learning and memory parameters were evaluated using elevated plus maze (EPM), passive avoidance and motor activity paradigms. Brain ChE activity and serum biochemical parameters like total cholesterol, total triglycerides and glucose were evaluated. RESULTS: It was observed that PA at the above-mentioned doses after 7 and 14 days of administration in the respective groups significantly reversed scopolamine (1 mg/kg i.p.)-induced amnesia, as evidenced by a decrease in the transfer latency in the EPM task and step-down latency in the passive avoidance task. PA reduced the brain ChE activity in rats. PA also exhibited a remarkable cholesterol and triglyceride lowering property and slight increase in glucose levels in the present study. CONCLUSION: Because diminished cholinergic transmission and increase in cholesterol levels appear to be responsible for the development of amyloid plaques and dementia in Alzheimer patients, PA may prove to be a useful memory-restorative agent. It would be worthwhile to explore the potential of this plant in the management of Alzheimer's disease.

Effect of leaves of Butea frondosa on stress, anxiety, and cognition in rats.

The plant Butea frondosa has been indicated in the Indian system of medicine as a plant augmenting memory and as a rejuvenator. The effect of oral administration of the aqueous and alcoholic extracts of the leaves was assessed on stress, cognitive function, and anxiety in albino rats. The antistress activity was evaluated using cold restraint induced ulcers and leukocyte count after subcutaneous injection of milk. The aqueous extract provides protection against stress-induced gastric lesions while both the alcoholic as well as the aqueous extract normalizes the white blood cell count. Effect on cognitive function was evaluated using Cook and Weidley's pole apparatus. The results indicate that the aqueous extract and the alcoholic extract when administered at a dose of 300 mg/kg for a period of 7 days augment both the acquisition as well as the retention of memory of learned task. The absence of an increase in the occupancy of the open arm in the elevated plus maze and in the number of head dips in the hole-board paradigms indicates that both the extracts are devoid of anxiolytic activity. Nootropic activity was compared using piracetam (100 mg/kg po) as the standard, while for anxiolytic and antistress activity, diazepam (1.0 mg/kg ip) was employed as the standard drug. It is concluded that the aqueous and alcoholic extract of B. frondosa possesses antistress and weak nootropic activity.

Clitoria ternatea and the CNS.

The present investigation was aimed at determining the spectrum of activity of the methanolic extract of Clitoria ternatea (CT) on the CNS. The CT was studied for its effect on cognitive behavior, anxiety, depression, stress and convulsions induced by pentylenetetrazol (PTZ) and maximum electroshock (MES). To explain these effects, the effect of CT was also studied on behavior mediated by dopamine (DA), noradrenaline, serotonin and acetylcholine. The extract decreased time required to occupy the central platform (transfer latency, TL) in the elevated plus maze (EPM) and increased discrimination index in the object recognition test, indicating nootropic activity. The extract was more active in the object recognition test than in the EPM. The extract increased occupancy in the open arm of EPM by 160% and in the lit box of the light/dark exploration test by 157%, indicating its anxiolytic activity. It decreased the duration of immobility in tail suspension test (suggesting its antidepressant activity), reduced stress-induced ulcers and reduced the convulsing action of PTZ and MES. The extract exhibited tendency to reduce the intensity of behavior mediated via serotonin and acetylcholine. The effect on DA- and noradrenaline-mediated behavior was not significant. In conclusion, the extract was found to possess nootropic, anxiolytic, antidepressant, anticonvulsant and antistress activity. Further studies are necessary to isolate the active principle responsible for the activities and to understand its mode of action.

Anxiolytic and antiemetic activity of Zingiber officinale.

The benzene fraction (BF) of a petroleum ether extract of dried rhizomes of ginger, which contained anticonvulsant principle(s), was screened for anxiolytic and antiemetic activity. Motor coordination was not affected by BF per se, but diazepam-induced motor incoordination was potentiated. Animals treated with BF showed decreased occupancy in the closed arm of the elevated plus maze suggesting the presence of anxiolytic principles in the BF. BF also blocked lithium sulphate-induced conditioned place aversion indicating antiemetic activity. These findings suggest that the fraction (BF) possesses anticonvulsant, anxiolytic and antiemetic activity.

Nootropic activity of Albizzia lebbeck in mice.

The effect of saponin containing n-butanolic fraction (BF) extracted from dried leaves of Albizzia lebbeck on learning and memory was studied in albino mice using passive shock avoidance paradigm and the elevated plus maze. Significant improvement was observed in the retention ability of the normal and amnesic mice as compared to their respective controls. We have also studied the effects of BF on the behavior influenced by serotonin (5-HT), noradrenaline and dopamine. The brain levels of serotonin, gamma-aminobutyric acid (GABA) and dopamine were also estimated to correlate the behavior with neurotransmitter levels. The brain concentrations of GABA and dopamine were decreased, whereas the 5-HT level was increased. The data indicate the involvement of monoamine neurotransmitters in the nootropic action of BF of A. lebbeck.

Anticonvulsive activity of Butea monosperma flowers in laboratory animals.

The bioassay-guided fractionation of dried flowers of Butea monosperma (BM) was carried out to isolate the active principle responsible for its anticonvulsant activity. The petroleum ether extract was fractionated by column chromatography using solvents of varying polarity such as n-hexane, n-hexane:ethyl acetate, ethyl acetate, and methanol. The anticonvulsive principle of B. monosperma was found to be a triterpene (TBM) present in the n-hexane:ethyl acetate (1:1) fraction of the petroleum ether extract. TBM exhibited anticonvulsant activity against seizures induced by maximum electroshock (MES) and its PD(50) was found to be 34.2+/-18.1 mg/kg. TBM also inhibited seizures induced by pentylenetetrazol (PTZ), electrical kindling, and the combination of lithium sulfate and pilocarpine nitrate (Li-Pilo). However, TBM was not effective against seizures induced by strychnine and picrotoxin. TBM exhibited depressant effect on the central nervous system. After repeated use for 7 days, the PD(50) (MES) of TBM increased to 51.5+/-12.1 mg/kg. Similarly, after repeated use of TBM, the duration of sleep induced by pentobarbital was not reduced significantly. Further studies are required to investigate its usefulness in the treatment of epilepsy.

Anxiogenic activity of Myristica fragrans seeds.

In the present study, the n-hexane extract of Myristica fragrans (MF) seeds, acetone-insoluble part of the n-hexane extract (AIMF) and trimyristin (TM) were assessed for their anxiogenic activity. The MF (10 and 30 mg/kg), AIMF (30, 100, and 300 mg/kg), and TM (10, 30, and 100 mg/kg) administered intraperitoneally exhibited anxiogenic activity in elevated plus-maze (EPM) paradigm. The open-field test and hole-board test were also used to assess anxiogenic activity of AIMF and TM. In the EPM test, MF, AIMF, and TM decreased the time spent by mice in the open arm and the entries in the open arm. Further, the effect of diazepam (1 mg/kg i.p.), serotonin 5-HT3 receptor antagonist, ondansetron (1 mg/kg i.p.), and 5-HT1A receptor agonist, buspirone (1 mg/kg i.p.), on the occupancy in open arm and entries in open arm was significantly reduced by TM. In the open-field test, AIMF as well as TM reduced the number of rearing and locomotion. Both TM and AIMF reduced the number of head pock in the hole-board test. Inhibition of anxiolytic activity of ondansetron (5-HT3 receptor antagonist), buspirone (5-HT1A receptor agonist), and diazepam [acting on gamma-aminobutyric acid (GABAA) receptor] suggests a nonspecific anxiogenic activity of TM and also a link between 5-HT and GABA systems in the anxiogenic activity of TM.

Nootropic and anxiolytic activity of saponins of Albizzia lebbeck leaves.

The effect of saponin containing, n-butanolic fraction (BF), extracted from dried leaves of Albizzia lebbeck, was studied on cognitive behavior and anxiety in albino mice. The elevated plus maze was used for assessment of both nootropic and anxiolytic activity. The nootropic activity was evaluated by recording the effect of BF (0, 10, 25, and 50 mg/kg) on the transfer latency, whereas anxiolytic activity was assessed by studying its effect on the duration of occupancy in the closed arm. Results showed significant improvement in the retention ability of the normal and amnesic mice as compared to their respective controls. Animals treated with BF (25 mg/kg) spent more time in the open arm in a dose-dependent manner. The BF was without any significant effect on motor coordination. However, it significantly inhibited passivity and hypothermia induced by baclofen (10 mg/kg), a GABA(B) agonist. The data emanated in the present study suggests involvement of gamma-aminobutyric acid (GABA) in the nootropic and anxiolytic activity of saponins obtained from A. lebbeck.

Anti - Inflammatory and analgesic Activity of Anacardium Occidentale Leaf Extracts.

The extracts of the dried leaves of Anacardium occidentale  were screened for anti-inflammatory activity using carrageenan induced rat paw edema model. The petroleum ether and chloroform extract and acetone soluble fraction of methanolic extract showed 57.14%, 47.61% and 61.90% inhibition of paw edema respectively. Acetone soluble extract showed better activity than petroleum either and chloroform extracts.

Effect of drugs influencing central serotonergic mechanisms on pentazocine-induced catalepsy in mice.

Cataleptic effect of pentazocine in mice was affected by pretreatment with dexfenfluramine, fluoxetine, buspirone, p-chlorophenylalanine, cyproheptadine, mianserin, cisapride, ondansetron, pindolol and propranolol. The results suggest that drugs which influence the activity of central serotonergic systems do modulate pentazocine-induced catalepsy in mice.

Baclofen-induced catatonia: modification by serotonergic agents.

Baclofen, a GABAB receptor agonist can induce catatonia in rats. This catatonia may serve as a tool for the study of GABAB receptor function. Reciprocal interactions between serotonin (5-HT) and GABAB receptors in the CNS are known to occur. In the present study we examined the effect of various agents that influence serotonergic neurotransmission on baclofen-induced catatonia in rats. The catatonia was rated by means of a scoring method, according to the severity of motor symptoms produced by baclofen (10-15 mg/kg, i.p.). All serotonergic drugs were injected intraperitoneally 30 min prior to baclofen, except the 5-HT synthesis inhibitor p-chlorophenylalanine (PCPA), which was injected 72 and 48 hr prior to baclofen. The 5-HT releaser fenfluramine (10 mg/kg) and the uptake inhibitor fluoxetine (10 mg/kg) reversed, whereas the 5-HT1A agonist buspirone (3 mg/kg) potentiated baclofen-induced catatonia. The 5-HT synthesis inhibitor PCPA (150 x 2 mg/kg), the non-specific 5-HT antagonist cyproheptadine (5 mg/kg), the 5-HT1A/1B antagonist pindolol (3 mg/kg) and the 5-HT2 antagonist sulpiride (20 mg/kg) enhanced baclofen-induced catatonia. It is concluded that the manipulations of central serotonergic mechanisms modulate baclofen-induced catatonia.