Mahendra Bishnoi

Anti-depressant like effect of curcumin and its combination with piperine in unpredictable chronic stress-induced behavioral, biochemical and neurochemical changes

Curcumin, a yellow pigment extracted from rhizomes of the plant Curcuma longa (turmeric), has been widely used as food additive and also as a herbal medicine throughout Asia. The present study was designed to study the pharmacological, biochemical and neurochemical effects of daily administration of curcumin to rats subjected to chronic unpredictable stress. Curcumin treatment (20 and 40 mg/kg, i.p., 21 days) significantly reversed the chronic unpredictable stress-induced behavioral (increase immobility period), biochemical (increase monoamine oxidase activity) and neurochemical (depletion of brain monoamine levels) alterations. The combination of piperine (2.5 mg/kg, i.p., 21 days), a bioavailability enhancer, with curcumin (20 and 40 mg/kg, i.p., 21 days) showed significant potentiation of its anti-immobility, neurotransmitter enhancing (serotonin and dopamine) and monoamine oxidase inhibitory (MAO-A) effects as compared to curcumin effect per se. This study provided a scientific rationale for the use of curcumin and its co-administration with piperine in the treatment of depressive disorders.

Suppression of NF-κβ signaling pathway by tocotrienol can prevent diabetes associated cognitive deficits

OBJECTIVE The etiology of diabetes associated cognitive decline is multifactorial and involves insulin receptor down regulation, neuronal apoptosis and glutamatergic neurotransmission. The study was designed to evaluate the impact of tocotrienol on cognitive function and neuroinflammatory cascade in streptozotocin-induced diabetes. RESEARCH DESIGN AND METHOD Streptozotocin-induced diabetic rats were treated with tocotrienol for 10 weeks. Morris water maze was used for behavioral assessment of memory. Cytoplasmic and nuclear fractions of cerebral cortex and hippocampus were prepared for the quantification of acetylcholinesterase activity, oxidative-nitrosative stress, tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), NFkappabeta and caspase-3. RESULTS After 10 weeks of streptozotocin injection, the rats produced significant increase in transfer latency which was coupled with enhanced acetylcholinesterase activity, increased oxidative-nitrosative stress, TNF-alpha, IL-1beta, caspase-3 activity and active p65 subunit of NFkappabeta in different regions of diabetic rat brain. Interestingly, co-administration of tocotrienol significantly and dose-dependently prevented behavioral, biochemical and molecular changes associated with diabetes. Moreover, diabetic rats treated with insulin-tocotrienol combination produced more pronounced effect on molecular parameters as compared to their per se groups. CONCLUSIONS Collectively, the data reveal that activation of NFkappabeta signaling pathway is associated with diabetes induced cognitive impairment and point towards the therapeutic potential of tocotrienol in diabetic encephalopathy.

Protective effect of Curcumin, the active principle of turmeric (Curcuma longa) in haloperidol-induced orofacial dyskinesia and associated behavioural, biochemical and neurochemical changes in rat brain

Tardive dyskinesia (TD) is a motor disorder of the orofacial region resulting from chronic neuroleptic treatment. A high incidence and irreversibility of this hyperkinetic disorder has been considered a major clinical issue in the treatment of schizophrenia. The molecular mechanism related to the pathophysiology of tardive dyskinesia is not completely known. Various animal studies have demonstrated an enhanced oxidative stress and increased glutamatergic transmission as well as inhibition in the glutamate uptake after the chronic administration of haloperidol. The present study investigated the effect of curcumin, an antioxidant, in haloperidol-induced tardive dyskinesia by using different behavioural (orofacial dyskinetic movements, stereotypy, locomotor activity, % retention), biochemical (lipid peroxidation, reduced glutathione levels, antioxidant enzyme levels (SOD and catalase) and neurochemical (neurotransmitter levels) parameters. Chronic administration of haloperidol (1 mg/kg i.p. for 21 days) significantly increased vacuous chewing movements (VCMs), tongue protrusions, facial jerking in rats which was dose-dependently inhibited by curcumin. Chronic administration of haloperidol also resulted in increased dopamine receptor sensitivity as evident by increased locomotor activity and stereotypy and also decreased % retention time on elevated plus maze paradigm. Pretreatment with curcumin reversed these behavioral changes. Besides, haloperidol also induced oxidative damage in all major regions of brain which was attenuated by curcumin, especially in the subcortical region containing striatum. On chronic administration of haloperidol, there was a decrease in turnover of dopamine, serotonin and norepinephrine in both cortical and subcortical regions which was again dose-dependently reversed by treatment with curcumin. The findings of the present study suggested for the involvement of free radicals in the development of neuroleptic-induced tardive dyskinesia and point to curcumin as a possible therapeutic option to treat this hyperkinetic movement disorder.

Chronic treatment with tocotrienol, an isoform of vitamin E, prevents intracerebroventricular streptozotocin-induced cognitive impairment and oxidative-nitrosative stress in rats.

Intracerebroventricular (ICV) streptozotocin (STZ) has been shown to cause cognitive impairment, which is associated with increased oxidative stress in the brain of rats. In the present study, we investigated the effect of both the isoforms of vitamin E, alpha-tocopherol and tocotrienol against ICV STZ-induced cognitive impairment and oxidative-nitrosative stress in rats. Adult male Wistar rats were injected with ICV STZ (3 mg/kg) bilaterally. The learning and memory behavior was assessed using Morris water maze and elevated plus maze. The rats were sacrificed on day 21 and parameters of oxidative stress, nitrite levels and acetylcholinesterase activity were measured in brain homogenate. alpha-Tocopherol as well as tocotrienol treated groups showed significantly less cognitive impairment in both the behavioral paradigms but the effect was more potent with tocotrienol. Both isoforms of vitamin E effectively attenuated the reduction in glutathione and catalase and reduced the malonaldehyde, nitrite as well as cholinesterase activity in the brains of ICV STZ rats in a dose dependent manner. The study demonstrates the effectiveness of vitamin E isoforms, of which tocotrienol being more potent in preventing the cognitive deficits caused by ICV STZ in rats and suggests its potential in the treatment of neurodegenerative diseases such as Alzheimers disease.

Protective effect of minocycline, a semi-synthetic second-generation tetracycline against 3-nitropropionic acid (3-NP)-induced neurotoxicity

3-Nitropropionic acid (3-NP) is an irreversible inhibitor of the electron transport enzyme succinate dehydrogenase, a mitochondrial Complex II enzyme. Minocycline is a semi-synthetic second-generation tetracycline with neuroprotective activity and has the capability to effectively cross the blood-brain barrier. We investigated the effects of minocycline on behavioral, biochemical, inflammation related and neurochemical alterations induced by the sub-chronic administration of 3-nitropropionic acid to rats. Chronic pre-administration of minocycline (50 and 100mg/kg) dose dependently prevented 3-NP-induced dysfunction behavioral (hypoactivity, memory retention, locomotor and rota-rod activity). In addition, 3-NP produced a marked increase in lipid peroxidation levels whereas decreased the activities of catalase and succinate dehydrogenase. In contrast, pretreatment of 3-NP injected rats with minocycline resulted in the attenuation of all these alterations. A marked increase in an inflammatory cytokine TNF-alpha by 3-NP was also decreased by minocycline treatment. Neurochemically, the administration of 3-NP significantly decreased the levels of catecholamines in the brain homogenates (dopamine, norepinephrine and serotonin) which were reversed by pretreatment of minocycline. The present finding explains the neuroprotective effect of minocycline against 3-NP toxicity by virtue of its antioxidant and anti-inflammatory activity.

Curcumin pretreatment protects against acute acrylonitrile-induced oxidative damage in rats

Acrylonitrile (AN) is widely used in the manufacturing of fibers, plastics and pharmaceuticals. Free radical-mediated lipid peroxidation is implicated in the toxicity of AN. The present study was designed to examine the ability of curcumin, a natural polyphenolic compound, to attenuate acute AN-induced lipid peroxidation in the brain and liver of rats. Male Sprague-Dawley rats were orally administered curcumin at doses of 0 (olive oil control), 50 or 100 mg/kg bodyweight daily for 7 consecutive days. Two hours after the last dose of curcumin, rats received an intraperitoneal injection of 50 mg AN/kg bodyweight. Acute exposure to AN significantly increased the generation of lipid peroxidation products, reflected by high levels of malondialdehyde (MDA) both in the brain and liver. These increases were accompanied by a significant decrease in reduced glutathione (GSH) content and a significant reduction in catalase (CAT) activity in the same tissues. No consistent changes in superoxide dismutase (SOD) activity were observed between the control and AN-treatment groups in both tissues. Pretreatment with curcumin reversed the AN-induced effects, reducing the levels of MDA and enhancing CAT activity and increasing reduced GSH content both in the brain and liver. Furthermore, curcumin effectively prevented AN-induced decrease in cytochrome c oxidase activity in both liver and brain. These results establish that curcumin pretreatment has a beneficial role in mitigating AN-induced oxidative stress both in the brains and livers of exposed rats and these effects are mediated independently of cytochrome P450 2E1 inhibition. Accordingly, curcumin should be considered as a potential safe and effective approach in attenuating the adverse effects produced by AN-related toxicants.

Protective effect of rutin, a polyphenolic flavonoid against haloperidol-induced orofacial dyskinesia and associated behavioural, biochemical and neurochemical changes

The occurrence and irreversibility of tardive dyskinesia (TD), a motor disorder of the orofacial region, resulting from chronic neuroleptic treatment has been considered a major clinical issue in the treatment of schizophrenia. The molecular mechanism underlying the pathophysiology of TD is not completely known. Several animal studies have demonstrated an enhancement of oxidative damage and increased glutamatergic transmission after chronic administration of neuroleptics. The present study investigated the effect of rutin, an antioxidant in haloperidol‐induced orofacial dyskinesia by using different behavioural (orofacial dyskinetic movements, stereotypic rearing, locomotor activity, percent retention), biochemical [lipid peroxidation, reduced glutathione levels, antioxidant enzyme levels (SOD and catalase)] and neurochemical (neurotransmitter levels) parameters. Chronic administration of haloperidol (1 mg/kg i.p. for 21 days) significantly increased vacuous chewing movements, tongue protrusions and facial jerking in rats, which were significantly inhibited by rutin. Chronic administration of haloperidol also resulted in dopamine receptor sensitivity as evident by a well‐shaped response (initial decrease followed by increase) in locomotor activity and stereotypic rearing and also decreased percent retention time on elevated plus maze paradigm. Pretreatment with rutin reversed these behavioural changes. Besides, haloperidol also induced oxidative damage in all regions of brain which was prevented by rutin, especially in the subcortical region containing striatum. Although turnover of dopamine and noradrenaline decreased in both cortical and subcortical regions after chronic administration of haloperidol, it was significantly reversed by high‐dose rutin treatment. The findings of the present study suggested the involvement of free radicals in the development of neuroleptic‐induced orofacial dyskinesia, a putative model of TD, and rutin as a possible therapeutic option to treat this hyperkinetic movement disorder.

Possible anti-oxidant and neuroprotective mechanisms of zolpidem in attenuating typical anti-psychotic-induced orofacial dyskinesia: a biochemical and neurochemical study.

Tardive dyskinesia is a serious motor side effect of chronic anti-psychotic therapy. The pathophysiology of this disabling and commonly irreversible movement disorder continues obscure and may be caused due to GABAergic hypofunction or increased oxidative damage and free radical generation. Chronic treatment with typical antipsychotics leads to the development of abnormal hyperkinetic orofacial movements (vacuous chewing movements, tongue protrusions and facial jerking) in rats and is widely accepted as the animal model for tardive dyskinesia. Zolpidem, a GABA-mimetic drug is structurally related to melatonin and has been reported to possess anti-oxidant and neuroprotective effects both in vivo and in vitro. The study was carried out to investigate whether zolpidem can be used in the treatment of typical anti-psychotic-induced orofacial dyskinesia. Chronic haloperidol (1 mg/kg, i.p. for 21 days) and chlorpromazine (5 mg/kg, i.p. for 21 days) treatment significantly induced orofacial hyperkinetic movements and zolpidem [N, N, 6-trimethyl-2-p-tolyl-imidazo (1, 2-a) pyridine 3-acetamideL-(+)] dose dependently (1, 2, 5 mg/kg i.p. for 21 days) reduced these haloperidol and chlorpromazine-induced hyperkinetic orofacial movements. Biochemical analysis revealed that haloperidol and chlorpromazine treatment significantly induced increase in lipid peroxidation and decrease in the levels of total nitric oxide levels, non-protein thiols (NPSH) and of anti-oxidant defense enzymes, superoxide dismutase (SOD) and catalase in the striatum of rat brain. Co-administration of zolpidem (1, 2, 5 mg/kg i.p. for 21 days) significantly reduced the lipid peroxidation and restored the non-protein thiols and total nitric oxide levels induced by chronic haloperidol and chlorpromazine treatment. It also significantly reversed the haloperidol and chlorpromazine-induced decrease in brain SOD and catalase activity. Neurochemical analysis (Neurotransmitter and their metabolite level estimation) revealed that haloperidol and chlorpromazine significantly decreased the dopamine, norepinephrine and serotonin levels in brain homogenates where as it caused a significant increase in the metabolite (VMA and HVA) levels in urine, which were significantly reversed by zolpidem at higher doses. Result of the present study support the therapeutic use of zolpidem in the treatment of typical anti-psychotic-induced orofacial dyskinesia.

Co-Administration of Acetyl-11-Keto-β-Boswellic Acid, a Specific 5-Lipoxygenase Inhibitor, Potentiates the Protective Effect of COX-2 Inhibitors in Kainic Acid-Induced Neurotoxicity in Mice

Cyclooxygenase (COX) and lipoxygenase (LOX) are responsible for the metabolism of arachidonic acid into inflammatory metabolites, prostaglandins and leukotrienes, respectively. The upregulation of these enzymes in the central nervous system has been demonstrated to be responsible for the increased neuronal vulnerability to degeneration. Kainic acid, a glutamate receptor agonist and responsible for neuronal excitotoxicity and oxidative damage via different mechanisms, is capable of stimulating mRNA of both COX-2 and 5-LOX in the brain. The present study was designed to study the effects of COX inhibitors (indomethacin, nimesulide, rofecoxib) and a 5-LOX inhibitor (acetyl-11-keto-β-boswellic acid; AKBA) and the combination of these inhibitors (dual inhibition) on kainic acid induced excitotoxicity and oxidative and nitrosative damage in mice. The results from the present study indicated that AKBA, indomethacin, and nimesulide per se did not produce any change in the behavioural parameters after kainic acid administration; however, rofecoxib per seproduced a significant increase in the latency of clonic (seizure-like) movement and a decrease in mortality rate as compared with kainic acid treated animals. In combination studies AKBA, rofecoxib, and nimesulide produced a more pronounced effect than either of these drugs alone. Further, the effect of AKBA combined with rofecoxib was significantly more marked when compared with AKBA combined with nimesulide. Besides this, identical results were found for the effect of these agents and their combination against oxidative damage induced by kainic acid. These findings indicate the potential role of COX-2 inhibitors and also their combination with the 5-LOX inhibitor in kainic acid induced excitotoxicity and oxidative damage by virtue of their antioxidant effect and suggest the need for the development of dual inhibitors for the treatment of neuronal excitotoxicity.

Development and validation of an RP‐HPLC method for the estimation of adenosine and related purines in brain tissues of rats

A new, rapid and sensitive RP-HPLC method with UV spectrophotometric detection was developed and validated for the concomitant estimation of adenosine and related purines in rat brain tissue preparations. The HPLC system consisted of C-18 column with UV-photodiode-array detection ranging from 210 to 400 nm, facilitating the online confirmation of peak purity. The column temperature was maintained at 30 degrees C and the injection volume was 20 muL. Elution with an isocratic mobile phase consisting of water/methanol/acetonitrile (88:5:7 by volume) at a flow rate of 0.8 mL/min yielded sharp, utmost-resolved peaks of adenosine (Ade), inosine (Ino), hypoxanthine (Hypoxan) and adenine (Adn) within 10 min. The method was validated with respect to the linearity, accuracy, precision, sensitivity, selectivity and stability. The method was also employed to estimate the naturally occurring purines in discrete regions of rat brain. A new protocol developed for tissue preparation utilizing H(2)SO(4) and Tris buffer gave well-resolved peaks and high component recoveries (>96%) which eliminated the need of an internal standard. The results show that the method for the determination of Ade, Ino, Hypoxan and Adn by RP-HPLC described here has good linearity, accuracy, precision, sensitivity, selectivity and is simple and rapid to perform.