Cannabinoid 2 Receptor Activation Protects against Diabetic Cardiomyopathy through Inhibition of AGE/RAGE-Induced Oxidative Stress, Fibrosis, and Inflammasome Activation.

Oxidative stress, fibrosis, and inflammasome activation from advanced glycation end product (AGE)-receptor of advanced glycation end product (RAGE) interaction contribute to diabetic cardiomyopathy (DCM) formation and progression. Our study revealed the impact of ß-caryophyllene (BCP) on activating cannabinoid type 2 receptors (CB2Rs) against diabetic complication, mainly cardiomyopathy and investigated the underlying cell signaling pathways in mice. The murine model of DCM was developed by feeding a high-fat diet with streptozotocin injections. After the development of diabetes, the animals received a 12-week oral BCP treatment at a dose of 50 mg/kg/body weight. BCP treatment showed significant improvement in glucose tolerance and insulin resistance and enhanced serum insulin levels in diabetic animals. BCP treatment effectively reversed the heart remodeling and restored the phosphorylated troponin I and sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a expression. Ultrastructural examination showed reduced myocardial cell injury in DCM mice treated with BCP. The preserved myocytes were found to be associated with reduced expression of AGE/RAGE in DCM mice hearts. BCP treatment mitigated oxidative stress by inhibiting expression of NADPH oxidase 4 and activating phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. Also, BCP suppressed cardiac fibrosis and endothelial-to-mesenchymal transition in DCM mice by inhibiting transforming growth factor ß (TGF-ß)/suppressor of mothers against decapentaplegic (Smad) signaling. Further, BCP treatment suppressed nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome activation in DCM mice and alleviated cellular injury to the pancreatic tissues evidenced by significant elevation of the number of insulin-positive cells. To demonstrate a CB2R-dependent mechanism of BCP, another group of DCM mice were pretreated with AM630, a CB2R antagonist. AM630 was observed to abrogate the beneficial effects of BCP in DCM mice. Taken together, BCP demonstrated the potential to protect the myocardium and pancreas of DCM mice mediating CB2R-dependent mechanisms. SIGNIFICANCE STATEMENT: BCP, a CB2R agonist, shows protection against DCM. BCP attenuates oxidative stress, inflammation, and fibrosis in DCM via activating CB2Rs. BCP mediating CB2R activation favorably modulates AGE/RAGE, PI3K/AKT/Nrf2ß and TGF-ß/Smad and (NLRP3) inflammasome in diabetic cardiomyopathy.

Limonene, a Monoterpene, Mitigates Rotenone-Induced Dopaminergic Neurodegeneration by Modulating Neuroinflammation, Hippo Signaling and Apoptosis in Rats.

Rotenone (ROT) is a naturally derived pesticide and a well-known environmental neurotoxin associated with induction of Parkinson's disease (PD). Limonene (LMN), a naturally occurring monoterpene, is found ubiquitously in citrus fruits and peels. There is enormous interest in finding novel therapeutic agents that can cure or halt the progressive degeneration in PD; therefore, the main aim of this study is to investigate the potential neuroprotective effects of LMN employing a rodent model of PD measuring parameters of oxidative stress, neuro-inflammation, and apoptosis to elucidate the underlying mechanisms. PD in experimental rats was induced by intraperitoneal injection of ROT (2.5 mg/kg) five days a week for a total of 28 days. The rats were treated with LMN (50 mg/kg, orally) along with intraperitoneal injection of ROT (2.5 mg/kg) for the same duration as in ROT-administered rats. ROT injections induced a significant loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and DA striatal fibers following activation of glial cells (astrocytes and microglia). ROT treatment enhanced oxidative stress, altered NF-κB/MAPK signaling and motor dysfunction, and enhanced the levels/expressions of inflammatory mediators and proinflammatory cytokines in the brain. There was a concomitant mitochondrial dysfunction followed by the activation of the Hippo signaling and intrinsic pathway of apoptosis as well as altered mTOR signaling in the brain of ROT-injected rats. Oral treatment with LMN corrected the majority of the biochemical, pathological, and molecular parameters altered following ROT injections. Our study findings demonstrate the efficacy of LMN in providing protection against ROT-induced neurodegeneration.

Tannic Acid Mitigates Rotenone-Induced Dopaminergic Neurodegeneration by Inhibiting Inflammation, Oxidative Stress, Apoptosis, and Glutamate Toxicity in Rats.

Parkinson's disease (PD), a movement disorder, is a neurodegenerative disease characterized by the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) region of the brain. The etiopathogenesis of PD involves increased oxidative stress, augmented inflammation, impaired autophagy, accumulation of α-synuclein, and α-Glutamate neurotoxicity. The treatment of PD is limited and there is a lack of agents to prevent the disease/delay its progression and inhibit the onset of pathogenic events. Many agents of natural and synthetic origin have been investigated employing experimental models of PD, mimicking human PD. In the present study, we assessed the effect of tannic acid (TA) in a rodent model of PD induced by rotenone (ROT), a pesticide and an environmental toxin of natural origin reported to cause PD in agricultural workers and farmers. Rotenone (2.5 mg/kg/day, i.p.) was administered for 28 days, and TA (50 mg/kg, orally) was administered 30 min before ROT injections. The study results showed an increase in oxidative stress, as evidenced by the depletion of endogenous antioxidants and enhanced formation of lipid peroxidation products, along with the onset of inflammation following a rise in inflammatory mediators and proinflammatory cytokines. ROT injections have also augmented apoptosis, impaired autophagy, promoted synaptic loss, and perturbed α-Glutamate hyperpolarization in rats. ROT injections also induced the loss of dopaminergic neurons subsequent to the activation of microglia and astrocytes. However, TA treatment was observed to reduce lipid peroxidation, prevent loss of endogenous antioxidants, and inhibit the release and synthesis of proinflammatory cytokines, in addition to the favorable modulation of apoptosis and autophagic pathways. Treatment with TA also attenuated the activation of microglia and astrocytes along with preservation of dopaminergic neurons following reduced loss of dopaminergic neurodegeneration and inhibition of synaptic loss and α-Glutamate cytotoxicity. The effects of TA in ROT-induced PD were attributed to the antioxidant, anti-inflammatory, antiapoptotic, and neurogenesis properties. Based on the present study findings, it can be concluded that TA may be a promising novel therapeutic candidate for pharmaceutical as well as nutraceutical development owing to its neuroprotective properties in PD. Further regulatory toxicology and translational studies are suggested for future clinical usage in PD.

α-Bisabolol, a Dietary Sesquiterpene, Attenuates Doxorubicin-Induced Acute Cardiotoxicity in Rats by Inhibiting Cellular Signaling Pathways, Nrf2/Keap-1/HO-1, Akt/mTOR/GSK-3ß, NF-κB/p38/MAPK, and NLRP3 Inflammasomes Regulating Oxidative Stress and Inflammatory Cascades.

Cancer chemotherapy with doxorubicin (DOX) may have multiorgan toxicities including cardiotoxicity, and this is one of the major limitations of its clinical use. The present study aimed to evaluate the cardioprotective role of α-Bisabolol (BSB) in DOX-induced acute cardiotoxicity in rats and the underlying pharmacological and molecular mechanisms. DOX (12.5 mg/kg, single dose) was injected intraperitoneally into the rats for induction of acute cardiotoxicity. BSB was given orally to rats (25 mg/kg, p.o. twice daily) for a duration of five days. DOX administration induced cardiac dysfunction as evidenced by altered body weight, hemodynamics, and release of cardio-specific diagnostic markers. The occurrence of oxidative stress was evidenced by a significant decline in antioxidant defense along with a rise in lipid peroxidation and hyperlipidemia. Additionally, DOX also increased the levels and expression of proinflammatory cytokines and inflammatory mediators, as well as activated NF-κB/MAPK signaling in the heart, following alterations in the Nrf2/Keap-1/HO-1 and Akt/mTOR/GSK-3ß signaling. DOX also perturbed NLRP3 inflammasome activation-mediated pyroptosis in the myocardium of rats. Furthermore, histopathological studies revealed cellular alterations in the myocardium. On the contrary, treatment with BSB has been observed to preserve the myocardium and restore all the cellular, molecular, and structural perturbations in the heart tissues of DOX-induced cardiotoxicity in rats. Results of the present study clearly demonstrate the protective role of BSB against DOX-induced cardiotoxicity, which is attributed to its potent antioxidant, anti-inflammatory, and antihyperlipidemic effects resulting from favorable modulation of numerous cellular signaling regulatory pathways, viz., Nrf2/Keap-1/HO-1, Akt/mTOR/GSK-3ß, NF-κB/p38/MAPK, and NLRP3 inflammasomes, in countering the cascades of oxidative stress and inflammation. The observations suggest that BSB can be a promising agent or an adjuvant to limit the cardiac injury caused by DOX. Further studies including the role in tumor-bearing animals as well as regulatory toxicology are suggested.

Myrcene Salvages Rotenone-Induced Loss of Dopaminergic Neurons by Inhibiting Oxidative Stress, Inflammation, Apoptosis, and Autophagy.

Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, resulting in motor deficits. The exact etiology of PD is currently unknown; however, the pathological hallmarks of PD include excessive production of reactive oxygen species, enhanced neuroinflammation, and overproduction of α-synuclein. Under normal physiological conditions, aggregated α-synuclein is degraded via the autophagy lysosomal pathway. However, impairment of the autophagy lysosomal pathway results in α-synuclein accumulation, thereby facilitating the pathogenesis of PD. Current medications only manage the symptoms, but are unable to delay, prevent, or cure the disease. Collectively, oxidative stress, inflammation, apoptosis, and autophagy play crucial roles in PD; therefore, there is an enormous interest in exploring novel bioactive agents of natural origin for their protective roles in PD. The present study evaluated the role of myrcene, a monoterpene, in preventing the loss of dopaminergic neurons in a rotenone (ROT)-induced rodent model of PD, and elucidated the underlying mechanisms. Myrcene was administered at a dose of 50 mg/kg, 30 min prior to the intraperitoneal injections of ROT (2.5 mg/kg). Administration of ROT caused a considerable loss of dopaminergic neurons, subsequent to a significant reduction in the antioxidant defense systems, increased lipid peroxidation, and activation of microglia and astrocytes, along with the production of pro-inflammatory cytokines (IL-6, TNF-α, IL-1ß) and matrix metalloproteinase-9. Rotenone also resulted in impairment of the autophagy lysosomal pathway, as evidenced by increased expression of LC3, p62, and beclin-1 with decreased expression in the phosphorylation of mTOR protein. Collectively, these factors result in the loss of dopaminergic neurons. However, myrcene treatment has been observed to restore antioxidant defenses and attenuate the increase in concentrations of lipid peroxidation products, pro-inflammatory cytokines, diminished microglia, and astrocyte activation. Myrcene treatment also enhanced the phosphorylation of mTOR, reinstated neuronal homeostasis, restored autophagy-lysosomal degradation, and prevented the increased expression of α-synuclein following the rescue of dopaminergic neurons. Taken together, our study clearly revealed the mitigating effect of myrcene on dopaminergic neuronal loss, attributed to its potent antioxidant, anti-inflammatory, and anti-apoptotic properties, and favorable modulation of autophagic flux. This study suggests that myrcene may be a potential candidate for therapeutic benefits in PD.

α-Bisabolol Attenuates Doxorubicin Induced Renal Toxicity by Modulating NF-κB/MAPK Signaling and Caspase-Dependent Apoptosis in Rats.

Doxorubicin (DOX) is a well-known and effective antineoplastic agent of the anthracycline family. But, multiple organ toxicities compromise its invaluable therapeutic usage. Among many toxicity types, nephrotoxicity is one of the major concerns. In recent years many approaches, including bioactive agents of natural origin, have been explored to provide protective effects against chemotherapy-related complications. α-Bisabolol is a naturally occurring monocyclic sesquiterpene alcohol identified in the essential oils of various aromatic plants and possesses a wide range of pharmacological properties such as antioxidant, anti-inflammatory, analgesic, cardioprotective, antibiotic, anti-irritant, and anticancer activities. The present study aimed to evaluate the effects of α-Bisabolol on DOX-induced nephrotoxicity in Wistar male albino rats. Nephrotoxicity was induced in rats by injecting a single dose of DOX (12.5 mg/kg, i.p.), and the test compound, α-Bisabolol (25 mg/kg) was administered intraperitoneally along with DOX as a co-treatment daily for 5 days. DOX-injected rats showed reduction in body weight along with a concomitant fall in antioxidants and increased lipid peroxidation in the kidney. DOX-injection also increased levels/expressions of proinflammatory cytokines namely tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß) and inflammatory mediators like inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and activated nuclear factor kappa-B (NF-κB)/mitogen-activated protein kinases (MAPK) signaling in the kidney tissues. DOX also triggered apoptotic cell death, evidenced by the increased expression of pro-apoptotic markers like BCL2-Associated X Protein (Bax), cleaved caspase-3, caspase- 9, and cytochrome-C) and a decrease in the expressions of anti-apoptotic markers namely B-cell lymphoma 2 (Bcl2) and B-cell lymphoma-extra large (Bcl-xL) in the kidney. These biochemical alterations were additionally supported by light microscopic findings, which revealed structural alterations in the kidney. However, treatment with α-Bisabolol prevented body weight loss, restored antioxidants, mitigated lipid peroxidation, and inhibited the rise in proinflammatory cytokines, as well as favorably modulated the expressions of NF-κB/MAPK signaling and apoptosis markers in DOX-induced nephrotoxicity. Based on the results observed, it can be concluded that α-Bisabolol has potential to attenuate DOX-induced nephrotoxicity by inhibiting oxidative stress and inflammation mediated activation of NF-κB/MAPK signaling alongwith intrinsic pathway of apoptosis in rats. The study findings are suggestive of protective potential of α-Bisabolol in DOX associated nephrotoxicity and this could be potentially useful in minimizing the adverse effects of DOX and may be a potential agent or adjuvant for renal protection.

Effect of camel milk protein hydrolysates against hyperglycemia, hyperlipidemia, and associated oxidative stress in streptozotocin (STZ)-induced diabetic rats.

This study investigated the effect of camel milk protein hydrolysates (CMPH) at 100, 500 and 1,000 mg/kg of body weight (BW) for 8 wk on hyperglycemia, hyperlipidemia, and associated oxidative stress in streptozotocin-induced diabetic rats. Body weights and fasting blood glucose levels were observed after every week until 8 wk, and oral glucose tolerance test (OGTT) levels and biochemical parameters were evaluated after 8 wk in blood and serum samples. Antioxidant enzyme activity and lipid peroxidation in the liver were estimated, and histological examination of the liver and pancreatic tissues was also conducted. Results showed that CMPH at 500 mg/kg of BW [camel milk protein hydrolysate, mid-level dosage (CMPH-M)] exhibited potent hypoglycemic activity, as shown in the reduction in fasting blood glucose and OGTT levels. The hypolipidemic effect of CMPH was indicated by normalization of serum lipid levels. Significant improvement in activity of superoxide dismutase and catalase, and reduced glutathione levels were observed, along with the attenuation of malondialdehyde content in groups fed CMPH, especially CMPH-M, was observed. Decreased levels of liver function enzymes (aspartate aminotransferase and alanine aminotransferase) in the CMPH-M group was also noted. Histology of liver and pancreatic tissue displayed absence of lipid accumulation in hepatocytes and preservation of ß-cells in the CMPH-M group compared with the diabetic control group. This is the first study to report anti-hyperglycemic and anti-hyperlipidemic effect of CMPH in an animal model system. This study indicates that CMPH can be suggested for its therapeutic benefits for hyperglycemia and hyperlipidemia, thus validating its use for better management of diabetes and associated comorbidities.

Noscapine Prevents Rotenone-Induced Neurotoxicity: Involvement of Oxidative Stress, Neuroinflammation and Autophagy Pathways.

Parkinson's disease is characterized by the loss of dopaminergic neurons in substantia nigra pars compacta (SNpc) and the resultant loss of dopamine in the striatum. Various studies have shown that oxidative stress and neuroinflammation plays a major role in PD progression. In addition, the autophagy lysosome pathway (ALP) plays an important role in the degradation of aggregated proteins, abnormal cytoplasmic organelles and proteins for intracellular homeostasis. Dysfunction of ALP results in the accumulation of α-synuclein and the loss of dopaminergic neurons in PD. Thus, modulating ALP is becoming an appealing therapeutic intervention. In our current study, we wanted to evaluate the neuroprotective potency of noscapine in a rotenone-induced PD rat model. Rats were administered rotenone injections (2.5 mg/kg, i.p.,) daily followed by noscapine (10 mg/kg, i.p.,) for four weeks. Noscapine, an iso-qinulinin alkaloid found naturally in the Papaveraceae family, has traditionally been used in the treatment of cancer, stroke and fibrosis. However, the neuroprotective potency of noscapine has not been analyzed. Our study showed that administration of noscapine decreased the upregulation of pro-inflammatory factors, oxidative stress, and α-synuclein expression with a significant increase in antioxidant enzymes. In addition, noscapine prevented rotenone-induced activation of microglia and astrocytes. These neuroprotective mechanisms resulted in a decrease in dopaminergic neuron loss in SNpc and neuronal fibers in the striatum. Further, noscapine administration enhanced the mTOR-mediated p70S6K pathway as well as inhibited apoptosis. In addition to these mechanisms, noscapine prevented a rotenone-mediated increase in lysosomal degradation, resulting in a decrease in α-synuclein aggregation. However, further studies are needed to further develop noscapine as a potential therapeutic candidate for PD treatment.

Valeric Acid Protects Dopaminergic Neurons by Suppressing Oxidative Stress, Neuroinflammation and Modulating Autophagy Pathways.

Parkinson's disease, the second common neurodegenerative disease is clinically characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) with upregulation of neuroinflammatory markers and oxidative stress. Autophagy lysosome pathway (ALP) plays a major role in degradation of damaged organelles and proteins for energy balance and intracellular homeostasis. However, dysfunction of ALP results in impairment of α-synuclein clearance which hastens dopaminergic neurons loss. In this study, we wanted to understand the neuroprotective efficacy of Val in rotenone induced PD rat model. Animals received intraperitoneal injections (2.5 mg/kg) of rotenone daily followed by Val (40 mg/kg, i.p) for four weeks. Valeric acid, a straight chain alkyl carboxylic acid found naturally in Valeriana officianilis have been used in the treatment of neurological disorders. However, their neuroprotective efficacy has not yet been studied. In our study, we found that Val prevented rotenone induced upregulation of pro-inflammatory cytokine oxidative stress, and α-synuclein expression with subsequent increase in vital antioxidant enzymes. Moreover, Val mitigated rotenone induced hyperactivation of microglia and astrocytes. These protective mechanisms prevented rotenone induced dopaminergic neuron loss in SNpc and neuronal fibers in the striatum. Additionally, Val treatment prevented rotenone blocked mTOR-mediated p70S6K pathway as well as apoptosis. Moreover, Val prevented rotenone mediated autophagic vacuole accumulation and increased lysosomal degradation. Hence, Val could be further developed as a potential therapeutic candidate for treatment of PD.

The Dual-Active Histamine H3 Receptor Antagonist and Acetylcholine Esterase Inhibitor E100 Alleviates Autistic-Like Behaviors and Oxidative Stress in Valproic Acid Induced Autism in Mice.

The histamine H3 receptor (H3R) functions as auto- and hetero-receptors, regulating the release of brain histamine (HA) and acetylcholine (ACh), respectively. The enzyme acetylcholine esterase (AChE) is involved in the metabolism of brain ACh. Both brain HA and ACh are implicated in several cognitive disorders like Alzheimer's disease, schizophrenia, anxiety, and narcolepsy, all of which are comorbid with autistic spectrum disorder (ASD). Therefore, the novel dual-active ligand E100 with high H3R antagonist affinity (hH3R: Ki = 203 nM) and balanced AChE inhibitory effect (EeAChE: IC50 = 2 µM and EqBuChE: IC50 = 2 µM) was investigated on autistic-like sociability, repetitive/compulsive behaviour, anxiety, and oxidative stress in male C57BL/6 mice model of ASD induced by prenatal exposure to valproic acid (VPA, 500 mg/kg, intraperitoneal (i.p.)). Subchronic systemic administration with E100 (5, 10, and 15 mg/kg, i.p.) significantly and dose-dependently attenuated sociability deficits of autistic (VPA) mice in three-chamber behaviour (TCB) test (all p < 0.05). Moreover, E100 significantly improved repetitive and compulsive behaviors by reducing the increased percentage of marbles buried in marble-burying behaviour (MBB) (all p < 0.05). Furthermore, pre-treatment with E100 (10 and 15 mg/kg, i.p.) corrected decreased anxiety levels (p < 0.05), however, failed to restore hyperactivity observed in elevated plus maze (EPM) test. In addition, E100 (10 mg/kg, i.p.) mitigated oxidative stress status by increasing the levels of decreased glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT), and decreasing the elevated levels of malondialdehyde (MDA) in the cerebellar tissues (all p < 0.05). Additionally, E100 (10 mg/kg, i.p.) significantly reduced the elevated levels of AChE activity in VPA mice (p < 0.05). These results demonstrate the promising effects of E100 on in-vivo VPA-induced ASD-like features in mice, and provide evidence that a potent dual-active H3R antagonist and AChE inhibitor (AChEI) is a potential drug candidate for future therapeutic management of autistic-like behaviours.

Nootkatone, a Dietary Fragrant Bioactive Compound, Attenuates Dyslipidemia and Intramyocardial Lipid Accumulation and Favorably Alters Lipid Metabolism in a Rat Model of Myocardial Injury: An In Vivo and In Vitro Study.

In the present study, we assessed whether nootkatone (NKT), a sesquiterpene in edible plants, can provide protection against dyslipidemia, intramyocardial lipid accumulation, and altered lipid metabolism in a rat model of myocardial infarction (MI) induced by subcutaneous injections of isoproterenol (ISO, 85 mg/kg) on days 9 and 10. The rats were pre- and co-treated with NKT (10 mg/kg, p.o.) administered daily for 11 days. A significant reduction in the activities of myocardial creatine kinase and lactate dehydrogenase, as well as non-enzymatic antioxidants, and alterations in lipids and lipoproteins, along with a rise in plasma lipid peroxidation and intramyocardial lipid accumulation, were observed in ISO-treated rats. ISO administration induced alterations in the activities of enzymes/expressions that played a significant role in altering lipid metabolism. However, NKT treatment favorably modulated all biochemical and molecular parameters altered by ISO and showed protective effects against oxidative stress, dyslipidemia, and altered lipid metabolism, attributed to its free-radical-scavenging and antihyperlipidemic activities in rats with ISO-induced MI. Additionally, NKT decreased the accumulation of lipids in the myocardium as evidenced from Oil red O staining. Furthermore, the in vitro observations demonstrate the potent antioxidant property of NKT. The present study findings are suggestive of the protective effects of NKT on dyslipidemia and the underlying mechanisms. Based on our findings, it can be suggested that NKT or plants rich in NKT can be promising for use as a phytopharmaceutical or nutraceutical in protecting the heart and correcting lipid abnormalities and dyslipidemia, which are risk factors for ischemic heart diseases.

Antagonism of Histamine H3 receptors Alleviates Pentylenetetrazole-Induced Kindling and Associated Memory Deficits by Mitigating Oxidative Stress, Central Neurotransmitters, and c-Fos Protein Expression in Rats.

Histamine H3 receptors (H3Rs) are involved in several neuropsychiatric diseases including epilepsy. Therefore, the effects of H3R antagonist E177 (5 and 10 mg/kg, intraperitoneal (i.p.)) were evaluated on the course of kindling development, kindling-induced memory deficit, oxidative stress levels (glutathione (GSH), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD)), various brain neurotransmitters (histamine (HA), acetylcholine (ACh), γ-aminobutyric acid (GABA)), and glutamate (GLU), acetylcholine esterase (AChE) activity, and c-Fos protein expression in pentylenetetrazole (PTZ, 40 mg/kg) kindled rats. E177 (5 and 10 mg/kg, i.p.) significantly decreased seizure score, increased step-through latency (STL) time in inhibitory avoidance paradigm, and decreased transfer latency time (TLT) in elevated plus maze (all P < 0.05). Moreover, E177 mitigated oxidative stress by significantly increasing GSH, CAT, and SOD, and decreasing the abnormal level of MDA (all P < 0.05). Furthermore, E177 attenuated elevated levels of hippocampal AChE, GLU, and c-Fos protein expression, whereas the decreased hippocampal levels of HA and ACh were modulated in PTZ-kindled animals (all P < 0.05). The findings suggest the potential of H3R antagonist E177 as adjuvant to antiepileptic drugs with an added advantage of preventing cognitive impairment, highlighting the H3Rs as a potential target for the therapeutic management of epilepsy with accompanied memory deficits.

Neuroinflammation: friend and foe for ischemic stroke.

Stroke, the third leading cause of death and disability worldwide, is undergoing a change in perspective with the emergence of new ideas on neurodegeneration. The concept that stroke is a disorder solely of blood vessels has been expanded to include the effects of a detrimental interaction between glia, neurons, vascular cells, and matrix components, which is collectively referred to as the neurovascular unit. Following the acute stroke, the majority of which are ischemic, there is secondary neuroinflammation that both promotes further injury, resulting in cell death, but conversely plays a beneficial role, by promoting recovery. The proinflammatory signals from immune mediators rapidly activate resident cells and influence infiltration of a wide range of inflammatory cells (neutrophils, monocytes/macrophages, different subtypes of T cells, and other inflammatory cells) into the ischemic region exacerbating brain damage. In this review, we discuss how neuroinflammation has both beneficial as well as detrimental roles and recent therapeutic strategies to combat pathological responses. Here, we also focus on time-dependent entry of immune cells to the ischemic area and the impact of other pathological mediators, including oxidative stress, excitotoxicity, matrix metalloproteinases (MMPs), high-mobility group box 1 (HMGB1), arachidonic acid metabolites, mitogen-activated protein kinase (MAPK), and post-translational modifications that could potentially perpetuate ischemic brain damage after the acute injury. Understanding the time-dependent role of inflammatory factors could help in developing new diagnostic, prognostic, and therapeutic neuroprotective strategies for post-stroke inflammation.

α-Bisabolol abrogates isoproterenol-induced myocardial infarction by inhibiting mitochondrial dysfunction and intrinsic pathway of apoptosis in rats.

Mitochondrial dysfunction plays crucial role in the pathologenesis of myocardial infarction (MI). The present study evaluated the protective effect of α-bisabolol against isoproterenol (ISO)-induced mitochondrial dysfunction and apoptosis in rats. Male albino Wistar rats were pre- and co-treated with intraperitoneal injection of α-bisabolol (25 mg/kg body weight) daily for 10 days. To induce experimental MI, ISO (85 mg/kg body weight) was injected subcutaneously to the rats at an interval of 24 h for 2 days (9th and 10th day). ISO-induced MI was indicated by the decreased activities of heart creatine kinase and lactate dehydrogenase in rats. ISO administration also enhanced the concentrations of heart mitochondrial lipid peroxidation products and decreased the activities/concentrations of mitochondrial antioxidants, Kreb's cycle dehydrogenases and mitochondrial electron transport chain complexes I, II + III and IV in rats. Furthermore, ISO triggers calcium overload and ATP depletion in the rat's heart mitochondria followed by the mitochondrial cytochrome-C release and the activation of intrinsic pathway of apoptosis by upregulating the myocardial pro-apoptotic Bax, P53, APAF-1, active caspase-3, active caspase-9 and down regulating the expressions of anti-apoptotic Bcl-2. α-Bisabolol pre and co-treatment showed considerable protective effects on all the biochemical and molecular parameters studied. Transmission electron microscopic study and mitochondrial swelling assay confirmed our biochemical and molecular findings. The in vitro study on hydroxyl radical also revealed the potent free radical scavenging activity of α-bisabolol. Thus, α-bisabolol attenuates mitochondrial dysfunction and intrinsic pathway of apoptosis in ISO-induced myocardial infarcted rats.

Neuroprotective Effects of Thymol, a Dietary Monoterpene Against Dopaminergic Neurodegeneration in Rotenone-Induced Rat Model of Parkinson's Disease.

Parkinson's disease (PD), a multifactorial movement disorder that involves progressive degeneration of the nigrostriatal system affecting the movement ability of the patient. Oxidative stress and neuroinflammation both are shown to be involved in the etiopathogenesis of PD. The aim of this study was to evaluate the therapeutic potential of thymol, a dietary monoterpene phenol in rotenone (ROT)-induced neurodegeneration in rats that precisely mimics PD in humans. Male Wistar rats were injected ROT at a dose of 2.5 mg/kg body weight for 4 weeks, to induce PD. Thymol was co-administered for 4 weeks at a dose of 50 mg/kg body weight, 30 min prior to ROT injection. The markers of dopaminergic neurodegeneration, oxidative stress and inflammation were estimated using biochemical assays, enzyme-linked immunosorbent assay, western blotting and immunocytochemistry. ROT challenge increased the oxidative stress markers, inflammatory enzymes and cytokines as well as caused significant damage to nigrostriatal dopaminergic system of the brain. Thymol treatment in ROT challenged rats appears to significantly attenuate dopaminergic neuronal loss, oxidative stress and inflammation. The present study showed protective effects of thymol in ROT-induced neurotoxicity and neurodegeneration mediated by preservation of endogenous antioxidant defense networks and attenuation of inflammatory mediators including cytokines and enzymes.

Lycopodium Attenuates Loss of Dopaminergic Neurons by Suppressing Oxidative Stress and Neuroinflammation in a Rat Model of Parkinson's Disease.

Parkinson's disease, a chronic, age related neurodegenerative disorder, is characterized by a progressive loss of nigrostriatal dopaminergic neurons. Several studies have proven that the activation of glial cells, presence of alpha-synuclein aggregates, and oxidative stress, fuels neurodegeneration, and currently there is no definitive treatment for PD. In this study, a rotenone-induced rat model of PD was used to understand the neuroprotective potential of Lycopodium (Lyc), a commonly-used potent herbal medicine. Immunohistochemcial data showed that rotenone injections significantly increased the loss of dopaminergic neurons in the substantia nigra, and decreased the striatal expression of tyrosine hydroxylase. Further, rotenone administration activated microglia and astroglia, which in turn upregulated the expression of α-synuclein, pro-inflammatory, and oxidative stress factors, resulting in PD pathology. However, rotenone-injected rats that were orally treated with lycopodium (50 mg/kg) were protected against dopaminergic neuronal loss by diminishing the expression of matrix metalloproteinase-3 (MMP-3) and MMP-9, as well as reduced activation of microglia and astrocytes. This neuroprotective mechanism not only involves reduction in pro-inflammatory response and α-synuclein expression, but also synergistically enhanced antioxidant defense system by virtue of the drug's multimodal action. These findings suggest that Lyc has the potential to be further developed as a therapeutic candidate for PD.

The Neuroprotective Effects of Histamine H3 Receptor Antagonist E177 on Pilocarpine-Induced Status Epilepticus in Rats.

Epilepsy is a multifaceted neurological disorder which severely affects neuronal function. Some patients may experience status epilepticus (SE), a life-threatening state of ongoing seizure activity linked to cognitive dysfunction, necessitating an immediate intervention. The potential of histamine H3 receptors in several neuropsychiatric diseases including epilepsy is well recognized. In the current study, we aimed to explore the effect of H3R antagonist E177 on prevention and termination of pilocarpine (PLC)-induced SE in rats as well as evaluating the effects of E177 on the levels of oxidative stress in hippocampus tissues. The results showed that the survival rate of animals pretreated with E177 (5 and 10 mg/kg, intraperitoneal (i.p.)) was significantly increased during the first hour of observation, and animals were protected from SE incidence and showed a prolonged average of latency to the first seizure when compared with animals pretreated with PLC (400 mg/kg, i.p.). Moreover, the protective effect of E177 (10 mg/kg) on SE was partially reversed when rats were co- administered with H3R agonist R-(α)-methylhistamine (RAM) and with the H2R antagonist zolantidine (ZOL), but not with the H1R antagonist pyrilamine (PYR). Furthermore, pretreatment with E177 (5 and 10 mg/kg) significantly decreased the abnormal levels of malondialdehyde (MDA), and increased levels of glutathione (GSH) in the hippocampal tissues of the treated rats. However, E177 failed to modulate the levels of catalase (CAT), superoxide dismutase (SOD), or acetylcholine esterase activity (AChE). Our findings suggest that the newly developed H3R antagonist E177 provides neuroprotection in a preclinical PLC-induced SE in rats, highlighting the histaminergic system as a potential therapeutic target for the therapeutic management of SE.

Protective effects of α-bisabolol on altered hemodynamics, lipid peroxidation, and nonenzymatic antioxidants in isoproterenol-induced myocardial infarction: In vivo and in vitro evidences.

The effect of α-bisabolol on hemodyanimcs, lipid peroxidation, and nonenzymatic antioxidants was evaluated in isoproterenol-induced myocardial infarction in rats. They were pre- and cotreated with α-bisabolol (25 mg/kg body weight) daily for 10 days along with the subcutaneous injection of isoproterenol (85 mg/kg body weight) at an interval of 24 hours for 2 days (9th and 10th days). Increased activities of serum creatine kinase and creatine kinase-MB along with altered levels/concentrations of lipid peroxidation products and nonenzymatic status were observed in the plasma and heart tissues of rats. Treatment with α-bisabolol showed protective effects by reversing the altered biochemical parameters and hemodynamics studied. The in vitro reducing power of α-bisabolol confirmed its potent antioxidant action. These biochemical benefits were translated into functional recovery by the maintenance of the hemodynamics in rats. The findings showed that α-bisabolol has the potential to protect against isoproterenol-induced myocardial infarction due to its potent antilipid peroxidation and antioxidant properties.

Neuroprotective effect of nerolidol against neuroinflammation and oxidative stress induced by rotenone.

BACKGROUND: Parkinson disease (PD) is a movement disorder affecting 1 % of people over the age of 60. The etiology of the disease is unknown; however, accumulating evidence suggests that mitochondrial defects, oxidative stress, and neuroinflammation play important roles in developing the disease. Current medications for PD can only improve its symptoms, but are unable to halt its progressive nature. Although many therapeutic approaches are available, new drugs are urgently needed for the treatment of PD. Thus, the present study was undertaken to investigate the neuroprotective potential of nerolidol, a sesquiterpene alcohol, on a rotenone-induced experimental model of PD, where male Wistar rats intraperitoneally received rotenone (ROT) at a dose of 2.5 mg/kg of body weight once daily for 4 weeks. RESULTS: Nerolidol, which has antioxidant and anti-inflammatory properties, was injected intraperitoneally at 50 mg/kg of body weight, once daily for 4 weeks, and at 30 min prior to ROT administration. ROT administration significantly reduced the activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the level of the antioxidant tripeptide glutathione (GSH). Moreover, ROT increased the levels of the lipid peroxidation product malondialdehyde (MDA), proinflammatory cytokines (IL-1ß, IL-6, and TNF-α), and inflammatory mediators (COX-2 and iNOS) in rat brain tissues. Immunostaining of brain tissue sections revealed a significant increase in the number of activated astrocytes (GFAP) and microglia (Iba-1), along with the concomitant loss of dopamine (DA) neurons in the substantia nigra pars compacta and dopaminergic nerve fibers in the striatum of ROT-treated rats. As expected, nerolidol supplementation to ROT-injected rats significantly increased the level of SOD, CAT, and GSH, and decreased the level of MDA. Nerolidol also inhibited the release of proinflammatory cytokines and inflammatory mediators. Finally, nerolidol treatment prevented ROT-induced glial cell activation and the loss of dopaminergic neurons and nerve fibers, and ultimately attenuated ROT-induced dopaminergic neurodegeneration. CONCLUSION: Our findings are the first to show that the neuroprotective effect of nerolidol is mediated through its anti-oxidant and anti-inflammatory activities, which strongly supports its therapeutic potential for the treatment of PD.

ß-Caryophyllene, a phytocannabinoid attenuates oxidative stress, neuroinflammation, glial activation, and salvages dopaminergic neurons in a rat model of Parkinson disease.

Parkinson disease (PD) is a neurodegenerative disease characterized by progressive dopaminergic neurodegeneration in the substantia nigra pars compacta (SNc) area. The present study was undertaken to evaluate the neuroprotective effect of ß-caryophyllene (BCP) against rotenone-induced oxidative stress and neuroinflammation in a rat model of PD. In the present study, BCP was administered once daily for 4 weeks at a dose of 50 mg/kg body weight prior to a rotenone (2.5 mg/kg body weight) challenge to mimic the progressive neurodegenerative nature of PD. Rotenone administration results in oxidative stress as evidenced by decreased activities of superoxide dismutase, catalase, and depletion of glutathione with a concomitant rise in lipid peroxidation product, malondialdehyde. Rotenone also significantly increased pro-inflammatory cytokines in the midbrain region and elevated the inflammatory mediators such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the striatum. Further, immunohistochemical analysis revealed loss of dopaminergic neurons in the SNc area and enhanced expression of ionized calcium-binding adaptor molecule-1 (Iba-1) and glial fibrillary acidic protein (GFAP), indicators of microglia activation, and astrocyte hypertrophy, respectively, as an index of inflammation. However, treatment with BCP rescued dopaminergic neurons and decreased microglia and astrocyte activation evidenced by reduced Iba-1 and GFAP expression. BCP in addition to attenuation of pro-inflammatory cytokines and inflammatory mediators such as COX-2 and iNOS, also restored antioxidant enzymes and inhibited lipid peroxidation as well as glutathione depletion. The findings demonstrate that BCP provides neuroprotection against rotenone-induced PD and the neuroprotective effects can be ascribed to its potent antioxidant and anti-inflammatory activities.