Rizwana Tabassum

Hesperidin ameliorates functional and histological outcome and reduces neuroinflammation in experimental stroke.

Incidence of stroke is considered to be a major cause of death throughout the world. The middle cerebral artery occlusion (MCAO) for 2h followed by 22h of reperfusion model was used in male Wistar rats to study the protection of stroke by hesperidin. Hesperidin administration (50mg/kg b.wt.) once daily for 15days has improved the infarct size, reduced the neurological deficits in terms of behaviors, and protected the elevated level of thiobarbituric acid reactive species (TBARS). A significantly depleted activity of antioxidant enzymes, glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD) and content of glutathione (GSH) in MCAO group were protected significantly in MCAO group pretreated with hesperidin. Moreover, inflammatory mediators like TNF-α, IL-1β levels, expression of iNOS and glial fibrillary acidic protein (GFAP) were significantly attenuated in H+MCAO group as compared to MCAO group. In conclusion, prophylactic treatment with hesperidin ameliorated the functional and histological outcomes with elevated endogenous antioxidants status as well as reduced induction of proinflammatory cytokines in MCA occluded rat. We theorized that hesperidin is among the pharmacological agents that reduce free radicals and its associated inflammation and have been found to limit the extent of brain damage following stroke.

S-allyl cysteine attenuates oxidative stress associated cognitive impairment and neurodegeneration in mouse model of streptozotocin-induced experimental dementia of Alzheimer's type

S-allyl cysteine (SAC), a sulfur containing amino acid derived from garlic, has been reported to have antioxidant, anti-cancer, antihepatotoxic and neurotrophic activity. This study was designed to examine the pre-treatment effects of SAC on cognitive deficits and oxidative damage in the hippocampus of intracerebroventricular streptozotocin (ICV-STZ)-infused mice. Mice pre-treated with SAC (30mg/kg) and vehicle (intraperitoneal; once daily for 15days) were bilaterally injected with ICV-STZ (2.57mg/kg body weight), whereas sham rats received the same volume of vehicle. The pre-treatment of this drug to Swiss albino mice has prevented the cognitive and neurobehavioral impairments. An increased latency and path length were observed in lesion, i.e. streptozotocin (STZ) group as compared to sham group and these were protected significantly in STZ group pre-treated with SAC. Levels of reduced glutathione (GSH) and its dependent enzymes (Glutathione peroxidase [GPx] and glutathione reductase [GR]) were decreased in STZ group as compared to sham group and pre-treatment of STZ group with SAC has protected their activities significantly. Conversely, the elevated level of thiobarbituric acid reactive substances (TBARS) in STZ group was attenuated significantly in SAC pre-treated group when compared with STZ lesioned group. Apoptotic parameters like DNA fragmentation, expression of Bcl2 and p53 were protected by the pre-treatment of SAC against STZ induced cognitive impairment. This study concludes that intervention of SAC could prevent free radicals associated deterioration of cognitive functions and neurobehavioral activities.

Naringenin ameliorates Alzheimer’s disease (AD)-type neurodegeneration with cognitive impairment (AD-TNDCI) caused by the intracerebroventricular-streptozotocin in rat model

Oxidative stress is involved in Alzheimers disease (AD)-type neurodegeneration with cognitive impairment (AD-TNDCI) as well as age related cognitive deficit. The present study was designed to investigate the pre-treatment effects of naringenin (NAR), a polyphenolic compound on cognitive dysfunction, oxidative stress in the hippocampus, and hippocampal neuron injury in a rat model of AD-TNDCI. The rats were pre-treated with NAR at a selective dose (50mg/kg, orally) for 2 weeks followed by intracerebroventricular-streptozotocin (ICV-STZ) (3mg/kg; 5μl per site) injection bilaterally. Behavioral alterations were monitored after 2 weeks from the lesion using passive avoidance test and Morris water maze paradigm. Three weeks after the lesion, the rats were sacrificed for measuring non-enzymatic [4-hydroxynonenal (4-HNE), malonaldehyde (MDA), thiobarbituric reactive substances (TBARS), hydrogen peroxide (H(2)O(2)), protein carbonyl (PC), reduced glutathione (GSH)] content and enzymatic [glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and Na(+)/K(+)-ATPase] activity in the hippocampus, and expression of choline acetyltransferase (ChAT) positive neuron, and histopathology of hippocampal neurons. The non-enzymatic level and enzymatic activity was significantly increased and decreased, respectively, with striking impairments in spatial learning and memory, loss of ChAT positive neuron and severe damage to hippocampal neurons in the rat induced by ICV-STZ. These abnormalities were significantly improved by NAR pre-treatment. The study suggests that NAR can protect against cognitive deficits, neuronal injury and oxidative stress induced by ICV-STZ, and may be used as a potential agent in treatment of neurodegenerative diseases such as AD-TNDCI.

Amelioration of cognitive impairment and neurodegeneration by catechin hydrate in rat model of streptozotocin-induced experimental dementia of Alzheimer’s type

Alzheimers disease (AD) is a progressive neurodegenerative disorder resulting in cognitive decline and enhancement of oxidative loads in the brain. Flavonoids have been considered to exert human health benefits by anti-oxidant and anti-inflammatory properties. The present study is aimed to elucidate the neuroprotective effect of catechin hydrate (CH), a natural flavanoid with potential antioxidant and anti-inflammatory properties, on intracerebroventricular streptozotocin (ICV-STZ) induced neuronal loss and memory impairment. To test this hypothesis, male Wistar rats were pretreated with CH (10 and 20mg/kgb wt) orally once daily for 21 days and then bilaterally injected with ICV-STZ (3mg/kgb wt), while sham group rats receive the same volume of vehicle. After 2 weeks of ICV-STZ infusion, rats were tested for cognitive performance using Morris water maze (MWM) test and then sacrifice for biochemical and histopathological assays. CH was found to be successful in upregulating the antioxidant status and prevented the memory loss. The expression of choline acetyl transferase (ChAT) was decreased in ICV-STZ group and CH pretreatment increases the expression of ChAT. Moreover, inflammatory mediators like TNF-α, IL-1β levels and expression of iNOS were significantly attenuated by CH pretreatment. The study suggests that CH is effective in preventing memory loss, ameliorating the oxidative stress and might be beneficial for the treatment of sporadic dementia of Alzheimers type (SDAT).

Effect of hesperidin on neurobehavioral, neuroinflammation, oxidative stress and lipid alteration in intracerebroventricular streptozotocin induced cognitive impairment in mice.

Recent attention is given to the influence of dietary supplementation on health and mental well-being. Oxidative stress is associated with many diseases including neurodegenerative disorders. Dietary flavonoids exert chemopreventive and neuroprotective effects and comprise the most common group of plant polyphenols that provide much of the flavour and colour of the vegetables and fruits. Hesperidin is a flavanone glycoside found abundantly in citrus fruits, has been reported to have antioxidant, hypolipidaemic, analgesic and anti-hypertensive activity. Pretreatment of hesperidin (100 and 200mg/kg body weight orally once daily for 15 days) to Swiss male albino mice has prevented the cognitive impairment. The cognitive impairment was developed by giving single intracerebroventricular-streptozotocin (ICV-STZ) injection (2.57 mg/kg body weight each side) bilaterally. Hesperidin pretreatment improved memory consolidation process as tested by Morris water maze possibly through modulation of acetylcholine esterase activity (AChE). Moreover, hesperidin attenuated the depleted content of reduced glutathione (GSH) and elevated level of thiobarbituric acid reactive substances (TBARS) and also augmented lipid alteration significantly following ICV-STZ injection. We also demonstrated that the flavonoid hesperidin modulates neuronal cell death by inhibiting the overexpression of inflammatory markers like nuclear factor κB, inducible nitric oxide synthase, cyclooxygenase-2 and glial fibrillary acidic protein positive astrocytes. The results from the present study open the possibility of using flavonoids for potential new therapeutic strategies for sporadic dementia of Alzheimers disease.

Perillyl alcohol improves functional and histological outcomes against ischemia–reperfusion injury by attenuation of oxidative stress and repression of COX-2, NOS-2 and NF-κB in middle cerebral artery occlusion rats

Perillyl alcohol (PA) is a monoterpene found in essential oils of mints, cherries, citreous fruits and lemon grass, reported to have antioxidant and anti-inflammatory properties. However, the role of PA in stroke is still illusive. Since oxidative stress and inflammation play a pivotal role in ischemia-reperfusion (I-R) injury, this study was designed to elucidate the potential effects of PA against I-R induced pathology in rat׳s brain. Middle cerebral artery occlusion (MCAO) for 2h followed by 22h reperfusion in Wistar male rats (250-280g, 14-16 weeks old) induced the behavioral and histological alterations along with exhausted antioxidant status and enhanced inflammatory mediators. However, PA administration (25, 50 and 100mg/kg b.wt orally once daily for 7 days) prior to MCAO significantly attenuated neurological deficits related to flexion test and spontaneous motor activity, improved grip strength and motor coordination in a dose dependent manner. PA treatment also inhibited oxidative stress in MCAO rats as evident from decreased lipid peroxidation and augmented level of reduced glutathione and restored activities of catalase, glutathione peroxidase, and glutathione reductase and thus, reduced infarct volume and protected the brain histology after I-R injury. Furthermore, PA markedly suppressed the level of proinflammatory cytokines (IL-1β, TNF α and IL-6) and down regulated expressions of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (NOS-2) and nuclear factor κB (NF-κB) in MCAO group. In conclusion, PA mediates neuroprotection against I-R injury via mitigation of oxidative stress and inflammation and thus, may be a good therapeutic approach in stroke prone patient.

Quercetin mitigates lead acetate-induced behavioral and histological alterations via suppression of oxidative stress, Hsp-70, Bak and upregulation of Bcl-2

Lead toxicity is of major health concern due to its persistence in environment that induces cognitive impairment and neuronal degeneration. The present study was conducted to investigate the efficacy of quercetin, a ubiquitous bioflavonoid against lead-induced neurotoxicity in Wistar rats. Briefly, lead acetate (20mg/kg) was injected i.p., followed by oral administration of quercetin (50 and 100mg/kg) once daily for five consecutive days. On 6th day, rats were assessed for motor co-ordination, grip strength and sensorimotor impairment (by adhesive removal test). Lead treated rats have shown marked behavioral impairment with increased oxidative stress. Quercetin reduced lead-induced oxidative burden in brain, thus maintained the normal behavioral functions of lead-intoxicated rats. The lead administered group showed severely vacuolated and pyknotic nuclei with high expressions of Bak and Hsp-70. The expression of anti-apoptotic Bcl-2 was observed to be reduced in lead intoxicated group. Quercetin however, restored the normal morphology of brain and the expressions of Bak, Bcl-2 and Hsp-70. In conclusion, quercetin mitigates the toxic effect of lead effectively and thus, may be an important compound for developing effective therapeutic intervention against metal toxicity.