Biomedical subjects

S B Acharya

Publications and source records attributed to S B Acharya.

At least 19 recordsLinked to original sources

PubMed2005

Neuroprotective effect of Azadirachta indica on cerebral post-ischemic reperfusion and hypoperfusion in rats.

We assessed the effect of Azadirachta indica (A. indica), a plant that has been reported to possess antioxidant, anti-inflammatory and anxiolytic properties, on cerebral reperfusion injury and long term cerebral hypoperfusion. When blood flow to brain region that has undergone critical period of ischemia is re-established, additional injury is to be expected from the reperfusion. In the present study, bilateral common carotid artery (BCCA) occlusion for 30 min followed by 45 min reperfusion resulted in increase in lipid peroxidation, superoxide dismutase (SOD) activity and fall in total tissue sulfhydryl (T-SH) groups. A. indica pretreatment (500 mg/kg/day x 7 days) attenuated the reperfusion induced enhanced lipid peroxidation, SOD activity and prevented fall in T-SH groups. Moreover, A.indica per se increased brain ascorbic acid level, which was unchanged during reperfusion insult. Long-term cerebral hypoperfusion induced by permanent BCCA occlusion has been reported to cause behavioral and histopathological abnormalities. In the present study, as tested by open field paradigm and Morris' water maze, a propensity towards anxiety and disturbances of learning/memory were observed in animals subjected to hypoperfusion for 2 weeks. A. indica (500 mg/kg/day x 15 days) significantly reduced these hypoperfusion induced functional disturbances. Reactive changes in brain histology like gliosis, perivascular lymphocytic infiltration, recruitment of macrophages and cellular edema following long term hypoperfusion were also attenuated effectively by A. indica. We conclude that our study provides an experimental evidence for possible neuroprotective potentiality of A. indica.

Animals↗

PubMed2004

Evaluation of antioxidant and neuroprotective effect of Ocimum sanctum on transient cerebral ischemia and long-term cerebral hypoperfusion.

Free radicals are implicated in causation of cerebral reperfusion injury and chronic cerebral hypoperfusion in rats is associated with functional and histopathological disturbances. Ocimum sanctum (OS), a plant widely used in Ayurveda, has been shown to possess anti-inflammatory, antioxidant and cognition-enhancing properties. In the present study, we investigated the effect of methanolic extract of OS leaves in cerebral reperfusion injury as well as long-term hypoperfusion. Occlusion of bilateral common carotid arteries (BCCA) for 30 min followed by 45 min reperfusion caused increase in lipid peroxidation and up-regulation of superoxide dismutase (SOD) activity accompanied by fall in tissue total sulfhydryl groups (TSH) in rat forebrains. Ascorbic acid levels were unchanged, however. OS pretreatment (200 mg/kg/day for 7 days) prevented this reperfusion-induced rise in lipid peroxidation and SOD activity. OS pretreatment also stabilized the levels of TSH during reperfusion. Long-term cerebral hypoperfusion (a model of cerebrovascular insufficiency and dementia) induced by permanent occlusion of BCCA for 15 days demonstrated altered exploratory behavior in open-field testing and memory deficits as tested by Morris' water maze. Histopathological examination of hypoperfused animals revealed reactive changes, like cellular edema, gliosis and perivascular inflammatory infiltrate. OS treatment (200 mg/kg/day for 15 days) significantly prevented these hypoperfusion-induced functional and structural disturbances. The results suggest that OS may be useful in treatment of cerebral reperfusion injury and cerebrovascular insufficiency states.

Animals↗

PubMed2004

Nimodipine attenuates biochemical, behavioral and histopathological alterations induced by acute transient and long-term bilateral common carotid occlusion in rats.

Restoration of blood flow to an ischemic brain region is associated with generation of reactive oxygen species with consequent reperfusion injury. Chronic cerebral hypoperfusion induced by permanent occlusion of bilateral common carotid arteries in rats is associated with behavioral and histopathological alterations. Nimodipine, a dihydropyridine calcium channel antagonist, has potent vasodilatory effect on cerebral vessels and increases cerebral blood flow. We analyzed whether nimodipine reduces injury caused by transient forebrain ischemia and long-term cerebral hypoperfusion. Bilateral common carotid occlusion for 30 min followed by 45 min reperfusion resulted in a two-fold increase in lipid peroxidation and superoxide dismutase activity. Nimodipine pretreatment (4 mg/kg, i.p.) brought down these levels by 30 and 23%, respectively. Long-term cerebral hypoperfusion in rats caused a propensity towards anxiety and listlessness (open field paradigm) accompanied by deficits of learning and memory (Morris' water maze testing). Additionally, histopathological observation in hypoperfused brains revealed reactive changes in the form of perivascular inflammation, gliosis and astrocytosis. Nimodipine treatment significantly alleviated these changes in behavioral and histopathological parameters. Our data confirm the protective role of nimodipine in ischemia reperfusion injury. Moreover, it suggests the beneficial role of nimodipine in cerebrovascular insufficiency states and dementia.

Animals↗

PubMed2003

Effect of Azadirachta indica on paracetamol-induced hepatic damage in albino rats.

Azadirachta indica, a plant used widely in Ayurveda, has been reported to have anti-inflammatory, immunomodulatory and adaptogenic properties. The present study evaluates its hepatoprotective role. Fresh juice of tender leaves of Azadirachta indica (200 mg/kg body wt. p.o.) inhibited paracetamol (2 g/kg body wt. p.o.)-induced lipid peroxidation and prevented depletion of sulfhydryl groups in liver cells. There was an increase in serum marker enzymes of hepatic damage (aspartate transaminase, alanine transaminase and alkaline phosphatase) after paracetamol administration. Azadirachta indica pretreatment stabilized the serum levels of these enzymes. Histopathological observations of liver tissues corroborated these findings.

Acetaminophen↗

PubMed2000

Pharmacological activity of Elaeocarpus sphaericus.

Elaeocarpus sphaericus fruits are used in Ayurveda for mental diseases, epilepsy, asthma, hypertension, arthritis and liver diseases. Sequential petroleum ether (PE), benzene (BE), chloroform (CE), acetone (AE) and ethanol (EE) extracts (50-200 or 200 mg/kg, ip, or 200 mg/kg, po) of dried Elaeocarpus sphaericus fruits, pretreatment time 30-45 min, showed significant antiinflammatory action against both acute and sub-acute models, analgesic, barbiturate-hypnosis potentiation and antiulcerogenic activities in rats. All the extracts, except PE and EE decreased swim stress immobility in mice indicating some degree of antidepressant activity. All the extracts protected guinea-pigs against bronchospasm induced by histamine and acetylcholine aerosols. Chemically, the extracts showed the presence of glycosides, steroids, alkaloids and flavonoids.

Animals↗

PubMed2000

Pharmacological activity of Abies pindrow.

The widely known tree Abies pindrow (Talisapatra) (family: Pinaceae), famous for its diverse clinical uses in Ayurvedic medicines, was investigated to rationalise some of the ancient claims. The petroleum ether (PE), benzene (BE), chloroform (CE), acetone (AE) and ethanol (EE) extracts of A. pindrow leaf were found to have mast cell stabilizing action in rats. The EE, AE and BE extracts offered bronchoprotection against histamine challenge in guinea-pigs. The BE, CE and PE extracts had protective role in aspirin-induced ulcer in rats. The results suggest that while terpenoids, flavonoids, glycosides and steroids are involved in mast cell protection, terpenoids and flavonoids are brochoprotective against histamine-induced bronchospasm. The ulcer protective action of PE, BE and CE fractions of A. pindrow may be attributable to steroids contents only because though all the extracts tested positive for glycosides, the extracts EE and AE did not have any ulcer protective role.

Animals↗

PubMed2000

Studies on extracts of Elaeocarpus sphaericus fruits on in vitro rat mast cells.

Elaeocarpus sphaericus (Syn: E. ganitrus), in Ayurvedic Medicine commonly known as Rudraksha is known to have wide range of pharmacological activities. We reported previously the protective action of E. sphaericus in experimental bronchial asthma. The present study on rat mesenteric mast cell was undertaken to investigate the effect of E. sphaericus fruits on autacoid release. The petroleum ether (PE), benzene (BE), chloroform (CE), acetone (AE) and ethanol (EE) extracts of E. sphaericus fruits were found to have mast-cell stabilizing activity, substantiating the efficacy of E. sphaericus against bronchial asthma.

Animals↗

PubMed2000

Anxiolytic activity of Indian Abies pindrow Royle leaves in rodents: an experimental study.

Putative anxiolytic activity of ethanolic extract of Indian A. pindrow Royle leaf was investigated in rats using various experimental paradigms of anxiety viz. open field exploratory behaviour, elevated plus maze (EPM) and elevated zero maze (EZM) tests. Pilot studies indicated that single dose administration of extract had little to no acute behavioural effects, hence the extract was administered orally at different dose levels once daily for three consecutive days, while lorazepam (LR) (0.5 mg/kg, i.p.) was administered acutely. Ethanolic extract of A. pindrow (AP) leaves (50 and 100 mg/kg, p.o.) showed significant anxiolytic effects on all the paradigms of anxiety. The results indicate that AP and LR induced a significant increase in open field ambulation and slight increase in rearings and activity in center, whereas grooming and faecal droppings remain unchanged. In EPM, significant augmentation of open arm entries, and time spent on open arms was noted in AP treated rats. In EZM test, significant increase in time spent on open arms and entries in open arms was observed, whereas slight increase in head dips and stretched attend postures was also observed. The AP extract showed consistent and significant anxiolytic activity in all the tests. The effects induced by ethanolic extract of AP were less marked than those of lorazepam were.

Animals↗

PubMed1999

Effect of fluoxetine on maximal electroshock seizures in mice: acute vs chronic administration.

There are no definite reports regarding the effects of chronic fluoxetine on animal models of epilepsy. Since chronically administered fluoxetine, in comparison to acutely administered fluoxetine has different effects on CNS, the present study was undertaken to investigate the effect of acute and chronic fluoxetine pretreatment, on a median anticonvulsant dose (ED50) of phenytoin in male ICR albino mice. Additionally, the effects of fluoxetine pretreatment on median convulsive current (CC50) in the presence and absence of phenytoin were investigated and results were compared. The maximal electroshock seizure (MES) test was used to estimate the ED50of phenytoin. The electroshock threshold test was used to estimate CC50. ED50and CC50values were calculated by probit analysis. The effects of the chronic and acute fluoxetine groups on the ED50of phenytoin were significantly different (P<0.05), and on CC50this difference was not statistically significant. Chronic fluoxetine insignificantly increased the ED50of phenytoin and decreased the CC50while acute fluoxetine decreased the ED50of phenytoin and increased the CC50. Our results indicate that chronic fluoxetine does not have an antiepileptic property and it may have dubious proconvulsant properties, contrary to acute fluoxetine.

Animals↗

PubMed1997

Pharmacological actions of Pongamia pinnata roots in albino rats.

Pongamia pinnata root has been advocated in Ayurveda for treatment of various inflammatory and infective conditions including ulcers. Sequential petroleum ether, benzene, chloroform, acetone and ethanolic extracts of P. pinnata roots when administered in the dose of 50 mg/kg, i.p. in rats was found to have anti-inflammatory, analgesic activity while pentobarbitone-induced 'sleep time' was reduced by all the extracts except petroleum ether which, however, enhanced it. They were also found to possess antiulcer effects when administered either by i.p. (45 min before) or oral route (45 min before or for 4 days) against restraint-stress or pylorus-ligated gastric ulcers in rats, the maximum protection being afforded by petroleum ether and ethanol extracts. The mechanism of antiulcer effect could either be due to decrease in acid-pepsin secretion and augmentation of mucin secretion as observed with ethanol extract, while petroleum ether extract might be producing the effect by virtue of its anti-stress activity.

Animals↗

PubMed1996

Neuropharmacological studies on Fusarium toxins-III: Neurochemical investigations on total toxin extracts from F. moniliforme and F. oxysporum.

Neurochemical effects of different fusarial toxins elaborated from F. moniliforme (FM) and F. oxysporum (FO) were investigated. FM showed significant nonspecific and irreversible monoamine oxidase (MAO) inhibition which was qualitatively comparable to that induced by nialamide, a nonselective MAO inhibitor. FO did not exhibit any significant MAO inhibitory effect. FM produced a dose related increase in monoamine concentrations (dopamine, noradrenaline and 5-hydroxytryptamine) in different rat brain areas namely, diencephalon-midbrain, caudate nucleus and pons-medulla. FO, on the contrary, produced marked increase in dopamine concentration in the caudate nucleus with concomitant reduction in noradrenaline levels in diencephalon-midbrain and pons-medulla with little effect on 5-HT concentration. The neurochemical effects of FM and FO are consonant with the earlier reports on the neuropharmacological profile of these toxins. Thus, FM was reported to have nialamide like activity, whereas FO actions were dopaminergic in nature.

Animals↗

PubMed1996

Neuropharmacological studies on Fusarium toxins--I: Total toxin extract from Fusarium moniliforme.

The neuropharmacological profile of the total fungal extract of F. moniliforme (FM) has been investigated. FM produced dose related decrease in spontaneous motor activity (SMA) and exploratory activity, potentiated pentobarbitone hypnosis and the anticonvulsant actions of phenobarbitone and phenytoin against MES seizures, potentiated PTZ and tryptamine seizures, antagonised reserpine induced syndrome, attenuated tetrabenazine and morphine induced catalepsy and potentiated haloperidol catalepsy. FM showed per se antinociceptive activity and potentiated morphine analgesia. It increased rectal temperature, antagonised reserpine and apomorphine hypothermia and potentiated the hyperthermic response of haloperidol and 5-hydroxytryptophan (5-HTP) and hypothermic response of betaphenylethylamine (PEA) and L-dopa. FM had no per se effect on amphetamine lethality, but enhanced the lethality induced by morphine in aggregated animals. Stereotypy by amphetamine was potentiated while that of apomorphine was not affected. The behavioural response of 5-HTP and L-dopa was potentiated. FM had no effect on swim induced behavioural despair. The effect on aggressive behavior was complex, and while the cumulative aggressive score was reduced, the onset of fighting behaviour and contact period was increased. It also inhibited clonidine induced auto mutilation. Since earlier investigation had shown that FM, like nialamide, induced non-selective inhibition of monoamine oxidase (MAO), the results were compared with those induced by nialamide. A comparative profile of action reveals that the neuropharmacological action of FM are qualitatively similar to those induced by nialamide, and likely to be due to inhibition of MAO. The investigation has practical implications because F. moniliforme is a common contaminant of cereals and fruits.

Analgesics↗

PubMed1996

Neuropharmacological studies on Fusarium toxins--II: Total toxin extract from F. oxysporum.

The neuropharmacological activity profile of total fungal extract of F. oxysporum (FO) was investigated. FO enhanced spontaneous locomotor activity, exploratory behaviour and reduced pentobarbitone hypnosis. It had per se anticonvulsant action against maximal electroshock seizure (MES) and potentiated phenobarbitone and phenytoin in MES and also potentiated pentylenetetrazol (PTZ) convulsion. It antagonised morphine, tetrabenazine and haloperidol catalepsy. FO did not show per se analgesia or potentiation of morphine antinociception in mice, while both effects were present in rats. The effect of FO on body temperature was complex. It produced per se reduction in rectal temperature and potentiated the hypothermic responses of reserpine, apomorphine, PEA and I-dopa, and also the hyperthermic response of 5-HTP. The hyperthermic response of haloperidol was reversed by FO. It potentiated amphetamine and morphine lethality, amphetamine, PEA and apomorphine stereotypy, 5-HTP headtwitch response and post-swim grooming response. On swim-stress immobility, while the time of onset of immobility was reduced, FO did not modify the duration of immobility. On foot-shock induced aggression in paired rats, FO produced a decrease in the latency to onset of fighting behaviour and increased the total contact period and the cumulative aggressive score. FO potentiated clonidine automutilation. It has, thus, facilitated aggressive behaviour. The effects are likely to be due to the presence of fusaric acid in FO, which inhibits dopamine beta-hydroxylase and is known to have dopaminergic effects. This investigation has practical implications. since F. oxysporum is a common food contaminant.

Analgesics↗

PubMed1996

Pharmacological actions of Pongamia pinnata seeds--a preliminary study.

Direct ethanolic and sequential petroleum ether, chloroform, acetone and ethanolic extracts (50-100 mg/kg, i.p.) of P. pinnata seeds given 30-60 min before revealed anti-inflammatory, analgesic and anti-ulcerogenic activities in rats. The activities were present maximum in petroleum ether and chloroform extracts. However, the extracts also showed shortening of pentobarbitone induced 'sleep time' in rats.

Analgesia↗

PubMed1995

Isatin, a putative anxiogenic endocoid, induces memory dysfunction in rats.

Isatin (2,3-dioxoindole), one of the components of tribulin, which has been postulated to function as an endogenous marker of stress and anxiety, was shown to induce a dose-related attenuation of learning acquisition in an active avoidance test and inhibition of learning retention, or memory, in a step-down passive avoidance paradigm and transfer latency in an elevated plus-maze, in rats. Earlier studies have indicated that isatin functions as a 5-hydroxytryptamine (5-HT)3 receptor agonist in its anxiogenic activity in rats and is an antagonist at mammalian atrial natriuretic peptide (ANP) receptors. Since 5-HT3 receptor antagonists and centrally administered ANP have been shown to facilitate learning and memory, the observed memory dysfunction induced by isatin can be attributed to its receptor activity at 5-HT3 and ANP receptors. The investigation also indicates that anxiogenic agents are likely to disrupt memory functions.

Animals↗

PubMed1995

Role of prostaglandin synthesis inhibitors on chemically induced seizures.

The study was conducted to find out the possible role of prostaglandin synthesis inhibitors on different parameters of chemically induced seizures in albino mice. The results suggest that prostaglandins have a proconvulsant activity. Augmentation of central dopamine and serotonin levels is partly responsible for the inhibitory effect of prostaglandin synthesis inhibitors on chemically induced seizures.

Animals↗

PubMed1994

Studies on peripheral actions of isatin.

The possible peripheral actions of isatin were studied in vivo and in vitro preparations in different experimental models, using conventional techniques. The results showed spasmogenic responses of isatin on guinea pig, rat and rabbit ileum and fundus of rat stomach. Histamine induced broncho-constriction could be antagonised by isatin. Isatin had cardioinhibitory effect on isolated frog heart and had hypotensive and respiratory depressant activities in dog. Isatin had antidiuretic effect. It was devoid of any effect on inflammation and gastric activities. The present results suggest a possible involvement of heterogenic 5-HT3 receptors in gastrointestinal smooth muscle.

Animals↗

PubMed1994

Anxiolytic activity of Azadirachta indica leaf extract in rats.

Putative anxiolytic activity of leaf extract of A. indica, was investigated and compared with that of diazepam in rats using elevated plus maze and open field behaviour test paradigms of anxiety. Doses (10, 20, 50, 100, 200, 400 and 800 mg/kg) of freshly prepared leaf extract of A. indica and diazepam (1 mg/kg) were administered (po) once, 45 min prior to behavioural testing. Low doses (10, 20, 50, 100 and 200 mg/kg) of A. indica leaf extract produced significant antianxiety effects both in plus maze and open field test. However, the higher doses of leaf extract (400 and 800 mg/kg) did not show anxiolytic activity. The effects induced by low doses (10, 20, 50, 100, 200 mg/kg) of extract were comparable to those of induced by diazepam (1 mg/kg).

Animals↗