Effects of isopulegol on pentylenetetrazol-induced convulsions in mice: possible involvement of GABAergic system and antioxidant activity

Phytotherapeutic options for the treatment of epilepsy: pharmacology, targets, and mechanism of action

Epilepsy is one of the most common, severe, chronic, potentially life-shortening neurological disorders, characterized by a persisting predisposition to generate seizures. It affects more than 60 million individuals globally, which is one of the major burdens in seizure-related mortality, comorbidities, disabilities, and cost. Different treatment options have been used for the management of epilepsy. More than 30 drugs have been approved by the US FDA against epilepsy. However, one-quarter of epileptic individuals still show resistance to the current medications. About 90% of individuals in low and middle-income countries do not have access to the current medication. In these countries, plant extracts have been used to treat various diseases, including epilepsy. These medicinal plants have high therapeutic value and contain valuable phytochemicals with diverse biomedical applications. Epilepsy is a multifactorial disease, and therefore, multitarget approaches such as plant extracts or extracted phytochemicals are needed, which can target multiple pathways. Numerous plant extracts and phytochemicals have been shown to treat epilepsy in various animal models by targeting various receptors, enzymes, and metabolic pathways. These extracts and phytochemicals could be used for the treatment of epilepsy in humans in the future; however, further research is needed to study the exact mechanism of action, toxicity, and dosage to reduce their side effects. In this narrative review, we comprehensively summarized the extracts of various plant species and purified phytochemicals isolated from plants, their targets and mechanism of action, and dosage used in various animal models against epilepsy.

Effects of the uremic toxin indoxyl sulfate on seizure activity, learning and brain oxidative stress parameters in mice

Patients with end-stage renal disease often have neurological disorders, with a higher incidence of memory impairment or epilepsy than in the general population. Patients undergoing hemodialysis are particularly exposed to the biological effects of uremic toxins. Indoxyl sulfate (IS) is one of the most potent uremic toxins; however, its possible effects on seizure susceptibility or memory functions have yet to be elucidated. In the current study, we focused on investigating the possible convulsant and amnesic effects of IS in recognized animal models. The study was performed on adult male Swiss mice. IS and scopolamine (SCO) were administered intraperitoneally (i.p.), and pentylenetetrazole (PTZ) was injected subcutaneously (s.c.). All substances were given as single injections. Acute IS administration (400 mg/kg) led to its accumulation in the brain. IS at doses of 200 and 400 mg/kg decreased the PTZ convulsive threshold, and at the same doses, it did not significantly affect the threshold for electroconvulsions. IS (200 and 400 mg/kg) did not impair learning in the passive avoidance test and did not increase the SCO-induced memory impairment in this test. IS increased lipid peroxidation, decreased the level of reduced glutathione, and reduced the activity of superoxide dismutase and catalase in mouse brains. Exposure to IS did not significantly change the activity of acetylcholinesterase in the brain tissue. This study shows that acute exposure to IS induces oxidative stress in the brain and potentiates PTZ-induced seizures in mice. Further studies are needed to find out whether IS-induced oxidative stress may affect epileptic seizures and/or epileptogenesis.

Oxidative Stress and Neurodegeneration in Animal Models of Seizures and Epilepsy

Free radicals are generated in the brain, as well as in other organs, and their production is proportional to the brain activity. Due to its low antioxidant capacity, the brain is particularly sensitive to free radical damage, which may affect lipids, nucleic acids, and proteins. The available evidence clearly points to a role for oxidative stress in neuronal death and pathophysiology of epileptogenesis and epilepsy. The present review is devoted to the generation of free radicals in some animal models of seizures and epilepsy and the consequences of oxidative stress, such as DNA or mitochondrial damage leading to neurodegeneration. Additionally, antioxidant properties of antiepileptic (antiseizure) drugs and a possible use of antioxidant drugs or compounds in patients with epilepsy are reviewed. In numerous seizure models, the brain concentration of free radicals was significantly elevated. Some antiepileptic drugs may inhibit these effects; for example, valproate reduced the increase in brain malondialdehyde (a marker of lipid peroxidation) concentration induced by electroconvulsions. In the pentylenetetrazol model, valproate prevented the reduced glutathione concentration and an increase in brain lipid peroxidation products. The scarce clinical data indicate that some antioxidants (melatonin, selenium, vitamin E) may be recommended as adjuvants for patients with drug-resistant epilepsy.

Computational Studies Applied to Linalool and Citronellal Derivatives Against Alzheimer's and Parkinson's Disorders: A Review with Experimental Approach

Alzheimer's and Parkinson's are neurodegenerative disorders that affect a great number of people around the world, seriously compromising the quality of life of individuals, due to motor and cognitive damage. In these diseases, pharmacological treatment is used only to alleviate symptoms. This emphasizes the need to discover alternative molecules for use in prevention. Using Molecular Docking, this review aimed to evaluate the anti-Alzheimer's and anti-Parkinson's activity of linalool and citronellal, as well as their derivatives. Before performing Molecular Docking simulations, the compounds' pharmacokinetic characteristics were evaluated. For Molecular Docking, 7 chemical compounds derived from citronellal, and 10 compounds derived from linalool, and molecular targets involved in Alzheimer's and Parkinson's pathophysiology were selected. According to the Lipinski rules, the compounds under study presented good oral absorption and bioavailability. For toxicity, some tissue irritability was observed. For Parkinson-related targets, the citronellal and linalool derived compounds revealed excellent energetic affinity for α-Synuclein, Adenosine Receptors, Monoamine Oxidase (MAO), and Dopamine D1 receptor proteins. For Alzheimer disease targets, only linalool and its derivatives presented promise against BACE enzyme activity. The compounds studied presented high probability of modulatory activity against the disease targets under study, and are potential candidates for future drugs.

Secondary Terpenes in Cannabis sativa L.: Synthesis and Synergy

Cannabis is a complex biosynthetic plant, with a long history of medicinal use. While cannabinoids have received the majority of the attention for their psychoactive and pharmacological activities, cannabis produces a diverse array of phytochemicals, such as terpenes. These compounds are known to play a role in the aroma and flavor of cannabis but are potent biologically active molecules that exert effects on infectious as well as chronic diseases. Furthermore, terpenes have the potential to play important roles, such as synergistic and/or entourage compounds that modulate the activity of the cannabinoids. This review highlights the diversity and bioactivities of terpenes in cannabis, especially minor or secondary terpenes that are less concentrated in cannabis on a by-mass basis. We also explore the question of the entourage effect in cannabis, which studies to date have supported or refuted the concept of synergy in cannabis, and where synergy experimentation is headed, to better understand the interplay between phytochemicals within Cannabis sativa L.

Pharmacological effects and therapeutic potential of natural compounds in neuropsychiatric disorders: An update

Neuropsychiatric diseases are a group of disorders that cause significant morbidity and disability. The symptoms of psychiatric disorders include anxiety, depression, eating disorders, autism spectrum disorders (ASD), attention-deficit/hyperactivity disorder, and conduct disorder. Various medicinal plants are frequently used as therapeutics in traditional medicine in different parts of the world. Nowadays, using medicinal plants as an alternative medication has been considered due to their biological safety. Despite the wide range of medications, many patients are unable to tolerate the side effects and eventually lose their response. By considering the therapeutic advantages of medicinal plants in the case of side effects, patients may prefer to use them instead of chemical drugs. Today, the use of medicinal plants in traditional medicine is diverse and increasing, and these plants are a precious heritage for humanity. Investigation about traditional medicine continues, and several studies have indicated the basic pharmacology and clinical efficacy of herbal medicine. In this article, we discuss five of the most important and common psychiatric illnesses investigated in various studies along with conventional therapies and their pharmacological therapies. For this comprehensive review, data were obtained from electronic databases such as MedLine/PubMed, Science Direct, Web of Science, EMBASE, DynaMed Plus, ScienceDirect, and TRIP database. Preclinical pharmacology studies have confirmed that some bioactive compounds may have beneficial therapeutic effects in some common psychiatric disorders. The mechanisms of action of the analyzed biocompounds are presented in detail. The bioactive compounds analyzed in this review are promising phytochemicals for adjuvant and complementary drug candidates in the pharmacotherapy of neuropsychiatric diseases. Although comparative studies have been carefully reviewed in the preclinical pharmacology field, no clinical studies have been found to confirm the efficacy of herbal medicines compared to FDA-approved medicines for the treatment of mental disorders. Therefore, future clinical studies are needed to accelerate the potential use of natural compounds in the management of these diseases.

Enantiomeric Isopulegol as the Chiral Pool in the Total Synthesis of Bioactive Agents

Isopulegol, a pool of abundant chiral terpene, has long served as the starting material for the total synthesis of isopulegol-based drugs. As an inexpensive and versatile starting material, this compound continues to serve modern synthetic chemistry. This review highlights the total syntheses of terpenoids in the period from 1980 to 2020 in which with isopulegol applied as a building block.

Antiseizure effects of Anacyclus pyrethrum in socially isolated rats with and without a positive handling strategy

OBJECTIVE

Aqueous extract of Anacyclus pyrethrum (AEAPR) is used in traditional medicine to treat epilepsy, but whether it has antiseizure properties has not been established. Because extracts of the plant have antioxidant properties, we hypothesized that it may be particularly potent in conditions associated with oxidative stress, in particular social isolation.

METHODS

We addressed these objectives in the pilocarpine experimental model of epilepsy using socially isolated rats maintaining contacts with (handled) and without (unhandled) positive handling strategy. Both groups were further divided into treated (AEAPR was added to the drinking water) and untreated groups. Continuous (24/7) electroencephalography (EEG) recordings started in the sixth week after status epilepticus (SE) with a predrug control period of 3 weeks, followed by 3 weeks of daily treatment with AEAPR or water, and finally a postdrug control period of 3 weeks. At the end of the experimental procedure, we measured lipid peroxidation, superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase activities in the hippocampus to assess oxidative stress.

RESULTS

A. pyrethrum treatment significantly reduced seizure frequency by 51% and 57%, duration by 30% and 33%, and severity by 31% and 26% in isolated handled and unhandled rats, respectively. The beneficial effects on seizures were still present 3 weeks after the end of the treatment. The treatment reduced lipid peroxidation as well as SOD, GPx, and catalase activities.

SIGNIFICANCE

We conclude that A. pyrethrum has antiseizure and antioxidant properties, even in social isolation conditions.

Modulatory effect of isopulegol on hepatic key enzymes of glucose metabolism in high-fat diet/streptozotocin-induced diabetic rats

To investigate the antidiabetic effect of isopulegol in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic rats. Animals were made diabetic by feeding HFD for 4 weeks followed by single intraperitoneal injection of STZ (35 mg/kg b.w.; 0.1 M citrate buffer; pH 4.0). Plasma insulin, haemoglobin and glycogen content were decreased while increased glucose and glycated haemoglobin were observed in diabetic rats. An increase in glucose-6-phosphatase, fructose-1,6-bisphosphatase, phosphoenol pyruvate carboxykinase with a decrease in hexokinase, glucose-6-phosphate dehydrogenase and glycogen synthase activities was observed in diabetic rats. The expression of cyclic response element binding protein (CREB) was increased in the hepatic tissue of diabetic rats. Isopulegol dose dependently (50, 100 and 200 mg/kg b.w.) improved insulin secretion, glucose tolerance and decreased glucose levels in diabetic-treated rats. At the effective dose of 100 mg/kg b.w., isopulegol restored the activities of metabolic enzymes and down-regulated CREB expression. Thus, isopulegol restored glucose homeostasis through its insulinotrophic property.

Determination of the Chemical Composition and Antimicrobial Activity of Lavatera thuringiaca L. Medicinal Herb Material Extracted under Subcritical Conditions by the Liquid Carbon Dioxide Method

This article presents the composition of the components of Lavatera thuringiaca L. (Malvaceae Juss. family), which has a certain antibacterial effect. The plant collection was carried out in the Shamalgan gorge of Mountain Range of the Trans-Ili Alatau in the territory of the Karasay district of the Almaty region, in the flowering phase. A CO₂ extract of the aboveground part of the medicinal plant Lavatera thuringiaca L. was obtained under subcritical conditions and, for the first time, studied for its component composition and antimicrobial activity. Determination of the chemical composition of the extract was carried out by gas chromatography/mass spectrometry (GC/MS). To identify the obtained mass spectra, we used the Wiley 7^th edition and the NIST'02 data library. To determine the antimicrobial and antifungal activity, standard test strains of microorganisms were used: Staphylococcus aureus ATCC 6538-P, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 10231, Streptococcus pneumonia ATCC 660, Klebsiella pneumoniae ATCC 700603, Staphylococcus haemolyticus, and Staphylococcus saprophyticus. In the composition of thick CO₂Lavatera thuringiaca L. extract, the content of 31 components was proven: spathulenol 6.97%, pulegone 5 08%, cis-β-farnesene 7.63%, verbenone 1.93%, α-bisabolol oxide B 9.65%, bisabolol oxide A 8.26%, α-bisabolol 1.36%, linolenic acid, ethyl ether 3.15%, phytol 2.49%, herniarin 5.61%, linolenic acid 9.38%, linoleic acid 6.95%, myristic acid 2.33%, and elaidic acid 2.57%. Antimicrobial activity studies have shown that the CO₂ extract of Lavatera thuringiaca L. has a pronounced effect against clinically significant microorganisms: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Streptococcus pneumonia, Klebsiella pneumoniae, Staphylococcus haemolyticus, and Staphylococcus saprophyticus. During testing, the method of serial dilutions proved that the extract of Lavatera thuringiaca L. has a bactericidal effect on Staphylococcus aureus at a concentration of 0.83 μg/μl, on Escherichia coli at a concentration of 3.33 μg/μl, on Pseudomonas aeruginosa at a concentration of 0.83 μg/μl, on Streptococcus pneumoniae at a concentration of 1.67 μg/μl, on a clinical isolate of Staphylococcus haemolyticus at a concentration of 26.65 μg/μl, on Staphylococcus saprophyticus at a concentration of 6.67 μg/μl, and against Klebsiella pneumoniae at a concentration of 13.36 μg/μl. The test result showed that the extract also has fungicidal activity against the test culture of Candida albicans at a concentration of 0.21 μg/μl. At tests, the disc diffusion method proved that the extract has antimicrobial activity with high values of the growth suppression zone exceeding 15 mm. The zones of growth retardation of the test strains were 19.33 ± 1.15 for Staphylococcus aureus; 17.33 ± 3.21 for Escherichia coli; 15.67 ± 0.57 for Pseudomonas aeruginosa; 20.0 ± 1.0 for Streptococcus pneumoniae; 16.0 ± 2.64 for Klebsiella pneumoniae; 15.0 ± 1.0 for Staphylococcus saprophyticus, and 22.0 ± 1.73 for Candida albicans. In relation to the clinical isolate of Staphylococcus haemolyticus, the extract has a bacteriostatic effect.

The Role of Poly-Herbal Extract in Sodium Chloride-Induced Oxidative Stress and Hyperlipidemia in Male Wistar Rats

Consistent consumption of high salt diet (HSD) has been associated with increased cellular generation of free radicals, which has been implicated in the derangement of some vital organs and etiology of cardiovascular disorders. This study was designed to investigate the combined effect of some commonly employed medicinal plants on serum lipid profile and antioxidant status of aorta, kidney, and liver of high salt diet-fed animals. Out of the total fifty male Wistar rats obtained, fifteen were used for acute toxicity study, while the remaining thirty-five were divided into 5 groups of 7 animals each. Group 1 and 2 animals were fed normal rat chow (NRC) and 16% high salt diet (HSD) only, respectively. Animals in groups 3, 4 and 5 were fed 16% HSD with 800, 400, and 200 mg/kg bw poly-herbal extract (PHE), respectively, once for 28 consecutive days. Serum low-density lipoprotein (LDL), triacylglycerol (TG), total cholesterol (TC) and high-density lipoprotein (HDL), malondialdehyde, nitric oxide, catalase, superoxide dismutase, glutathione peroxidase, glutathione concentration, and activities were assessed in the aorta, kidney, and liver. Poly-herbal extract (p < 0.05) significantly reduced malondialdehyde and nitric oxide concentrations and also increased antioxidant enzymes and glutathione activity. Elevated serum TG, TC, LDL, and TC content in HSD-fed animals were significantly (p < 0.05) reduced to normal in PHE-treated rats while HDL was significantly elevated (p < 0.05) in a concentration-dependent manner in PHE treated animals. Feeding with PHE attenuated high-salt diet imposed derangement in serum lipid profile and antioxidant status in the organs of the experimental rats.

Natural Compounds as Medical Strategies in the Prevention and Treatment of Psychiatric Disorders Seen in Neurological Diseases

Psychiatric disorders are frequently encountered in many neurological disorders, such as Alzheimer’s and Parkinson diseases along with epilepsy, migraine, essential tremors, and stroke. The most common comorbid diagnoses in neurological diseases are depression and anxiety disorders along with cognitive impairment. Whether the underlying reason is due to common neurochemical mechanisms or loss of previous functioning level, comorbidities are often overlooked. Various treatment options are available, such as pharmacological treatments, cognitive-behavioral therapy, somatic interventions, or electroconvulsive therapy. However oral antidepressant therapy may have some disadvantages, such as interaction with other medications, low tolerability due to side effects, and low efficiency. Natural compounds of plant origin are extensively researched to find a better and safer alternative treatment. Experimental studies have shown that phytochemicals such as alkaloids, terpenes, flavonoids, phenolic acids as well as lipids have significant potential in in vitro and in vivo models of psychiatric disorders. In this review, various efficacy of natural products in in vitro and in vivo studies on neuroprotective and their roles in psychiatric disorders are examined and their neuro-therapeutic potentials are shed light.

Potential anti-epileptic phytoconstituents: An updated review

ETHNOPHARMACOLOGICAL RELEVANCE

Epilepsy is one of the most commonly occurring non-communicable neurological disorder that affects people of all age groups. Around 50 million people globally are epileptic, with 80% cases in developing countries due to lack of access to treatments determined by high cost and poor availability or it can be defined by the fraction of active epileptic patients who are not appropriately being treated. The availability of antiepileptic drugs and their adjuvant therapy in such countries is less than 50% and these are highly susceptible to drug interactions and severe adverse effects. As a result, the use of herbal medicine is increasingly becoming popular.

AIM OF THE STUDY

To provide pharmacological information on the active constituents evaluated in the preclinical study to treat epilepsy with potential to be used as an alternative therapeutic option in future. It also provides affirmation for the development of novel antiepileptic drugs derived from medicinal plants.

MATERIALS AND METHODS

Relevant information on the antiepileptic potential of phytoconstituents in the preclinical study (in-vitro, in-vivo) is provided based on their effect on screening parameters. Besides, relevant information on pharmacology of phytoconstituents, the traditional use of their medicinal plants related to epilepsy and status of phytoconstituents in the clinical study were derived from online databases, including PubMed, Clinicaltrial. gov, The Plant List (TPL, www.theplantlist.org), Science Direct. Articles identified using preset searching syntax and inclusion criteria are presented.

RESULTS

More than 70% of the phytoconstituents reviewed in this paper justified the traditional use of their medicinal plant related to epilepsy by primarily acting on the GABAergic system. Amongst the phytoconstituents, only cannabidiol and tetrahydrocannabinol have been explored for clinical application in epilepsy.

CONCLUSION

The preclinical and clinical data of the phytoconstituents to treat epilepsy and its associated comorbidities provides evidence for the discovery and development of novel antiepileptic drugs from medicinal plants. In terms of efficacy and safety, further randomized and controlled clinical studies are required to understand the complete pharmacodynamic and pharmacokinetic picture of phytoconstituents. Also, specific botanical source evaluation is needed.

Limonene has anti-anxiety activity via adenosine A2A receptor-mediated regulation of dopaminergic and GABAergic neuronal function in the striatum

BACKGROUND

Limonene, a common terpene found in citrus fruits, is assumed to reduce stress and mood disorders. Dopamine and γ-aminobutyric acid (GABA) have been reported to play an important role in modulating anxiety in different parts of the brain.

HYPOTHESIS/PURPOSE

Herein, we report the anxiolytic activity of limonene. In addition, we identified a possible mechanism underlying the effect of limonene on DAergic and GABAergic neurotransmission.

STUDY DESIGN

In this study, mice were injected with saline in the control group and limonene in the test group before behavioral analysis. We performed immunoblotting and high-performance liquid chromatography (HPLC) analysis after the behavioral study.

RESULTS

The limonene treated group showed increased locomotor activity and open-arm preference in the elevated plus maze experiment. Limonene treatment increased the expression of both tyrosine hydroxylase and GAD-67 proteins and significantly upregulated dopamine levels in the striatum. Furthermore, tissue dopamine levels were increased in the striatum of mice following limonene treatment, and depolarization-induced GABA release was enhanced by limonene pre-treatment in PC-12 cells. Interestingly, limonene-induced anxiolytic activity and GABA release augmentation were blocked by an adenosine A2A receptor (A2AR) antagonist.

CONCLUSION

Our results suggest that limonene inhibits anxiety-related behavior through A2A receptor-mediated regulation of DAergic and GABAergic neuronal activity.

Monoterpenes as a perspective for the treatment of seizures: A Systematic Review

BACKGROUND

Epilepsy affects more than 65 million people worldwide. Treatment for epileptic seizures is ineffective and has many adverse effects. For this reason, the search for new therapeutic options capable of filling these limitations is necessary.

HYPOTHESIS/PURPOSE

In this sense, natural products, such as monoterpenes, have been indicated as a new option to control neurological disorders such as epilepsy.

STUDY DESIGN

Therefore, the objective of this study was to review the monoterpenes that have anticonvulsive activity in animal models.

METHODS

The searches were performed in the PubMed, Web of Science and Scopus databases in September, 2020 and compiled studies using monoterpenes as an alternative to seizure. Two independent reviewers performed the study selection, data extraction and methodological quality assessment using the Syrcle tool.

RESULTS

51 articles that described the anticonvulsant activity of 35 monoterpenes were selected with action on the main pharmacological target, including GABAA receptors, glutamate, calcium channels, sodium and potassium. In addition, these compounds are capable of reducing neuronal inflammation and oxidative stress caused by seizure.

CONCLUSION

These compounds stand out as a promising alternative for acting through different pharmacological mechanisms, which may not only reduce seizure, but also promote neuroprotective effect by reducing toxicity in brain regions. However, further studies are needed to determine the mechanism of action and safety assessment of these compounds.

Attenuation of potassium dichromate and sodium arsenite toxicities by methanol extract of Rauvolfia vomitoria in mice

OBJECTIVES

Exposure to arsenic and hexavalent chromium is a major public health concern especially in the developing part of the world and there is paucity of information on reliable treatment modalilities. It is in this regard that this study evaluates the efficacy of methanol leaf extract of Rauvolfia vomitoria (MRV) when used as pretreatment agent against potassium dichromate (K₂Cr₂O₇) and sodium arsenite (NaAsO₂) exposure.

METHODS

Swiss albino mice between 7 and 10 weeks old were divided into eight cohorts of five animals each. Treatment groups consisted of a distilled water control, MRV alone (275 mg/kg po daily), K₂Cr₂O₇ (12.0 mg/kg, single ip injection) +/- MRV pretreatment, NaAsO₂ (2.5 mg/kg, single ip injection) +/- MRV pretreatment, Na₂AsO₂ + K₂Cr₂O₇ +/- MRV pretreatment. MRV was given for seven consecutive days, while K₂Cr₂O₇ and NaAsO₂ were injected on day seven of the experiment. The frequency of micronucleated polychromatic erythrocytes (mPCEs) was determined in bone marrow cells, while aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were assessed in the plasma. Hepatic glutathione (GSH), malondialdehyde (MDA), catalase (CAT) and glutathione-S-transferase (GST) levels were also determined.

RESULTS

The NaAsO₂ and K₂Cr₂O₇ significantly (p<0.05) increased mPCE formation, AST, ALT, and CAT when compared with the control. Simultaneous exposure to NaAsO₂ and K₂Cr₂O₇ further increased the levels of the markers. Furthermore, GSH and GST were significantly reduced by NaAsO₂ or K₂Cr₂O₇ or their combination. Pretreatment with MRV reversed the markers towards that of control.

CONCLUSIONS

Methanol extract of Rauvolfia vomitoria may therefore ameliorate NaAsO₂ and K₂Cr₂O₇-induced toxicities via reduction of oxidative stress and fortification of anti-oxidant system.

Antiedematogenic and Anti-Inflammatory Activity of the Monoterpene Isopulegol and Its β-Cyclodextrin (β-CD) Inclusion Complex in Animal Inflammation Models

Isopulegol (ISO) is an alcoholic monoterpene widely found in different plant species, such as Melissa officinalis, and has already been reported to have a number of pharmacological properties. Like other terpenes, ISO is a highly volatile compound that is slightly soluble in water, so its inclusion into cyclodextrins (CDs) is an interesting approach to increase its solubility and bioavailability. Thus, our aim was to evaluate the antiedematogenic and anti-inflammatory activity of isopulegol and a β-cyclodextrin-isopulegol inclusion complex (ISO/β-CD) in rodent models. For the anti-inflammatory activity evaluation, antiedematogenic plethysmometry and acute (peritonitis and pleurisy), as well as chronic (cotton pellet-induced granuloma) anti-inflammatory models, were used. The docking procedure is used to evaluate, analyze, and predict their binding mode of interaction with H1 and Cox-2 receptors. The animals (n = 6) were divided into groups: ISO and ISO/β-CD, negative control (saline), and positive control (indomethacin and promethazine). ISO and ISO/β-CD were able to reduce acute inflammatory activity by decreasing albumin extravasation, leukocyte migration, and MPO concentration, and reducing exudate levels of IL-1β and TNF-α. ISO and ISO/β-CD significantly inhibited edematogenic activity in carrageenan- and dextran-induced paw edema. Moreover, both significantly reduced chronic inflammatory processes, given the lower weight and protein concentration of granulomas in the foreign body granulomatous inflammation model. The results suggest that the inclusion of ISO in β-cyclodextrins improves its pharmacological properties, with the histamine and prostaglandin pathways as probable mechanisms of inhibition, and also reinforces the anti-inflammatory profile of this terpene.

Isopulegol Mitigates Hyperglycemia Mediated Oxidative and Endoplasmic Reticulum Stress in HFD/STZ Induced Diabetic Rats

BACKGROUND

Oxidative and endoplasmic reticulum stresses contribute to the pathogenesis of β-cell dysfunction in diabetes mellitus. This study investigates the effect of isopulegol on the above stresses in HFD/STZ induced diabetic rats.

METHODS

Animals in group I and II were placed in normal pellet diet and group II was treated with isopulegol at 200 mg/kg b.w. Animals in groups III-V were placed in HFD for 4 weeks and made diabetic with single intraperitoneal injection of STZ (35 mg/kg b.w) in 0.1 M citrate buffer (pH 4.5). Group III served as diabetic control while animals in group IV and V were treated with isopulegol (100 mg/kg b.w) and metformin (25 mg/kg b.w) respectively for 28 d.

RESULTS

The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione sulphur transferase (GST), glutathione reductase (GR) and the levels of vitamin-E, vitamin-C, reduced glutathione (GSH) were significantly (p <0.05) decreased in plasma and tissues of diabetic rats. Thiobarbituric acid reactive acid substances (TBARS) and lipid hydroperoxides (LHP), indices of lipid peroxidation were also significantly (p <0.05) increased in diabetic rats. In pancreatic tissue ER stress markers PERK, elf2α, ATF4 and in hepatic tissue oxidative stress marker UCP-2 expression was significantly (p <1.0) increased in diabetic rats. Administration of isopulegol significantly improved antioxidant status and decreased oxidative and ER stress markers in diabetic treated rats. Histopathological studies on liver and kidney supported the above findings. The results are comparable with the standard drug metformin.

CONCLUSIONS

Isopulegol a naturally occurring monoterpene alcohol attenuated oxidative and ER stress in HFD/STZ induced diabetic rats.

Medicinal Properties of Cannabinoids, Terpenes, and Flavonoids in Cannabis, and Benefits in Migraine, Headache, and Pain: An Update on Current Evidence and Cannabis Science

BACKGROUND

Comprehensive literature reviews of historical perspectives and evidence supporting cannabis/cannabinoids in the treatment of pain, including migraine and headache, with associated neurobiological mechanisms of pain modulation have been well described. Most of the existing literature reports on the cannabinoids Δ⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD), or cannabis in general. There are many cannabis strains that vary widely in the composition of cannabinoids, terpenes, flavonoids, and other compounds. These components work synergistically to produce wide variations in benefits, side effects, and strain characteristics. Knowledge of the individual medicinal properties of the cannabinoids, terpenes, and flavonoids is necessary to cross-breed strains to obtain optimal standardized synergistic compositions. This will enable targeting individual symptoms and/or diseases, including migraine, headache, and pain.

OBJECTIVE

Review the medical literature for the use of cannabis/cannabinoids in the treatment of migraine, headache, facial pain, and other chronic pain syndromes, and for supporting evidence of a potential role in combatting the opioid epidemic. Review the medical literature involving major and minor cannabinoids, primary and secondary terpenes, and flavonoids that underlie the synergistic entourage effects of cannabis. Summarize the individual medicinal benefits of these substances, including analgesic and anti-inflammatory properties.

CONCLUSION

There is accumulating evidence for various therapeutic benefits of cannabis/cannabinoids, especially in the treatment of pain, which may also apply to the treatment of migraine and headache. There is also supporting evidence that cannabis may assist in opioid detoxification and weaning, thus making it a potential weapon in battling the opioid epidemic. Cannabis science is a rapidly evolving medical sector and industry with increasingly regulated production standards. Further research is anticipated to optimize breeding of strain-specific synergistic ratios of cannabinoids, terpenes, and other phytochemicals for predictable user effects, characteristics, and improved symptom and disease-targeted therapies.

Medicinal properties of terpenes found in Cannabis sativa and Humulus lupulus

Cannabaceae plants Cannabis sativa L. and Humulus lupulus L. are rich in terpenes - both are typically comprised of terpenes as up to 3-5% of the dry-mass of the female inflorescence. Terpenes of cannabis and hops are typically simple mono- and sesquiterpenes derived from two and three isoprene units, respectively. Some terpenes are relatively well known for their potential in biomedicine and have been used in traditional medicine for centuries, while others are yet to be studied in detail. The current, comprehensive review presents terpenes found in cannabis and hops. Terpenes' medicinal properties are supported by numerous in vitro, animal and clinical trials and show anti-inflammatory, antioxidant, analgesic, anticonvulsive, antidepressant, anxiolytic, anticancer, antitumor, neuroprotective, anti-mutagenic, anti-allergic, antibiotic and anti-diabetic attributes, among others. Because of the very low toxicity, these terpenes are already widely used as food additives and in cosmetic products. Thus, they have been proven safe and well-tolerated.

Excavating Anticonvulsant Compounds from Prescriptions of Traditional Chinese Medicine in the Treatment of Epilepsy

Traditional Chinese medicine (TCM) has a long history and been widely used in prevention and treatment of epilepsy in China. This paper is intended to review the advances in the active anticonvulsant compounds isolated from herbs in the prescription of TCM in the treatment of epilepsy. These compounds were introduced with the details including classification, CAS number specific structure and druggability data. Meanwhile, much of the research in these compounds in the last two decades has shown that they exhibited favorable pharmacological properties in treatment of epilepsy both in in vivo and in vitro models. In addition, in this present review, the evaluation of the effects of the anticonvulsant classical TCM prescriptions is discussed. According to these rewarding pharmacological effects and chemical substances, the prescription of TCM herbs could be an effective therapeutic strategy for epilepsy patients, and also could be a promising source for the development of new drugs.

Essential Oils and Their Constituents Targeting the GABAergic System and Sodium Channels as Treatment of Neurological Diseases

Essential oils and the constituents in them exhibit different pharmacological activities, such as antinociceptive, anxiolytic-like, and anticonvulsant effects. They are widely applied as a complementary therapy for people with anxiety, insomnia, convulsion, pain, and cognitive deficit symptoms through inhalation, oral administration, and aromatherapy. Recent studies show that essential oils are emerging as a promising source for modulation of the GABAergic system and sodium ion channels. This review summarizes the recent findings regarding the pharmacological properties of essential oils and compounds from the oils and the mechanisms underlying their effects. Specifically, the review focuses on the essential oils and their constituents targeting the GABAergic system and sodium channels, and their antinociceptive, anxiolytic, and anticonvulsant properties. Some constituents target transient receptor potential (TRP) channels to exert analgesic effects. Some components could interact with multiple therapeutic target proteins, for example, inhibit the function of sodium channels and, at the same time, activate GABAA receptors. The review concentrates on perspective compounds that could be better candidates for new drug development in the control of pain and anxiety syndromes.

Cardiovascular Activity of the Chemical Constituents of Essential Oils

Cardiovascular diseases are a leading cause of death in developed and developing countries and decrease the quality of life, which has enormous social and economic consequences for the population. Recent studies on essential oils have attracted attention and encouraged continued research of this group of natural products because of their effects on the cardiovascular system. The pharmacological data indicate a therapeutic potential for essential oils for use in the treatment of cardiovascular diseases. Therefore, this review reports the current studies of essential oils chemical constituents with cardiovascular activity, including a description of their mechanisms of action.

Monoterpenes as a renewable source of biologically active compounds

Monoterpenes and their derivatives play an important role in the creation of new biologically active compounds including drugs. The review focuses on the data on various types of biological activity exhibited by monoterpenes and their derivatives, including analgesic, anti-inflammatory, anticonvulsant, antidepressant, anti-Alzheimer, anti-Parkinsonian, antiviral, and antibacterial (anti-tuberculosis) effects. Searching for novel potential drugs among monoterpene derivatives shows great promise for treating various pathologies. Special attention is paid to the effect of absolute configuration of monoterpenes and monoterpenoids on their activity.

Metabolic Products of Linalool and Modulation of GABAA Receptors

Terpenoids are major subcomponents in aroma substances which harbor sedative physiological potential. We have demonstrated that various monoterpenoids such as the acyclic linalool enhance GABAergic currents in an allosteric manner in vitro upon overexpression of inhibitory α1β2 GABA_A receptors in various expression systems. However, in plants or humans, i.e., following intake via inhalation or ingestion, linalool undergoes metabolic modifications including oxygenation and acetylation, which may affect the modulatory efficacy of the generated linalool derivatives. Here, we analyzed the modulatory potential of linalool derivatives at α1β2γ2 GABA_A receptors upon transient overexpression. Following receptor expression control, electrophysiological recordings in a whole cell configuration were used to determine the chloride influx upon co-application of GABA EC₁₀₋₃₀ together with the modulatory substance. Our results show that only oxygenated linalool metabolites at carbon 8 positively affect GABAergic currents whereas derivatives hydroxylated or carboxylated at carbon 8 were rather ineffective. Acetylated linalool derivatives resulted in non-significant changes of GABAergic currents. We can conclude that metabolism of linalool reduces its positive allosteric potential at GABA_A receptors compared to the significant potentiation effects of the parent molecule linalool itself.

Effect of Naringenin (A naturally occurring flavanone) Against Pilocarpine-induced Status Epilepticus and Oxidative Stress in Mice

BACKGROUND

Epilepsy is a disorder of the central nervous system characterized by recurrent seizures. It is a very common disease in which approximately 30% of patients do not respond favourably to treatment with anticonvulsants. Oxidative stress is associated with neuronal damage arising from epileptic seizures. The present study investigated the effects of naringenin in pilocarpine-induced epilepsy in mice. Naringenin, one of the most frequently occurring flavanone in citrus fruits, was evaluated for its shielding effect against the pilocarpine induced behavioural, oxidative and histopathological alterations in rodent model of epilepsy.

METHODOLOGY

Epilepsy was induced by giving pilocarpine (300mg/kg) and sodium valproate (300mg/kg) was given as standard anti-epileptic drug Pilocarpine was administered (300 mg /kg body weight) intraperitoneally to the mice on 15th day while naringenin was administered orally (20 and 40 mg/kg body weight) for 15 days prior to administration of pilocarpine.

RESULTS

The intraperitoneal administration of pilocarpine enhanced lipid peroxidation, caused reduction in antioxidant enzymes, viz., catalase, superoxide dismutase and glutathione reductase. Treatment of mice orally with naringenin (20 mg/kg body weight and 40 mg/kg body weight) resulted in a significant decrease in lipid peroxidation. There was significant recovery of glutathione content and all the antioxidant enzymes studied. Also in case of behavioural parameters studied, naringenin showed decrease in seizure severity. All these changes were supported by histological observations, which revealed excellent improvement in neuronal damage.

CONCLUSION

The higher dose of naringenin was more potent in our study and was comparable to the standard drug (sodium valproate) in effectiveness.

SUMMARY

Naringenin ameliorated the development of ROS formation in hippocamus.Naringenin helped in recovery of antioxidant enzymes.Naringenin decreased seizure severity.Naringenin treatment reduced lipid peroxidation. Abbreviations used: 6-OHDA: 6-hydroxydopamine, AED: Anti epileptic drugs, AIDS: Acquired immune deficiency syndrome, ANOVA: Analysis of variance, ATP: Adenosine triphosphate, CA: Cornu ammonis, CAT: Catalase, DG: Dentate gyrus, EDTA: Ethylenediamine tetra acetic acid, GR: Glutathione reductase, GSH: Glutathione reduced, HCl: Hydrochloric acid, IL-1β: Interleukin 1 beta, LPO: Lipid peroxidation, MDA: Malondialdehyde, NADPH: Nicotinamide adenine dinucleotide phosphate, PMS: post mitochondrial supernatant, SE: Status epilepticus, SEM: Standard error of the mean, SOD Superoxide dismutase, TBA: Thiobarbituric acid, TBARS: Thiobarbituric acid reactive substance, TLE: Temporal lobe epilepsy, TNF-α: Tumor necrosis factor alpha.

Effect of Naringenin (A naturally occurring flavanone) Against Pilocarpine-induced Status Epilepticus and Oxidative Stress in Mice

Background:

Epilepsy is a disorder of the central nervous system characterized by recurrent seizures. It is a very common disease in which approximately 30% of patients do not respond favourably to treatment with anticonvulsants. Oxidative stress is associated with neuronal damage arising from epileptic seizures. The present study investigated the effects of naringenin in pilocarpine-induced epilepsy in mice. Naringenin, one of the most frequently occurring flavanone in citrus fruits, was evaluated for its shielding effect against the pilocarpine induced behavioural, oxidative and histopathological alterations in rodent model of epilepsy.

Methodology:

Epilepsy was induced by giving pilocarpine (300mg/kg) and sodium valproate (300mg/kg) was given as standard anti-epileptic drug Pilocarpine was administered (300 mg /kg body weight) intraperitoneally to the mice on 15th day while naringenin was administered orally (20 and 40 mg/kg body weight) for 15 days prior to administration of pilocarpine.

Results:

The intraperitoneal administration of pilocarpine enhanced lipid peroxidation, caused reduction in antioxidant enzymes, viz., catalase, superoxide dismutase and glutathione reductase. Treatment of mice orally with naringenin (20 mg/kg body weight and 40 mg/kg body weight) resulted in a significant decrease in lipid peroxidation. There was significant recovery of glutathione content and all the antioxidant enzymes studied. Also in case of behavioural parameters studied, naringenin showed decrease in seizure severity. All these changes were supported by histological observations, which revealed excellent improvement in neuronal damage.

Conclusion:

The higher dose of naringenin was more potent in our study and was comparable to the standard drug (sodium valproate) in effectiveness.

SUMMARY

Naringenin ameliorated the development of ROS formation in hippocamus.

Naringenin helped in recovery of antioxidant enzymes.

Naringenin decreased seizure severity.

Naringenin treatment reduced lipid peroxidation.

Abbreviations used: 6-OHDA: 6-hydroxydopamine, AED: Anti epileptic drugs, AIDS: Acquired immune deficiency syndrome, ANOVA: Analysis of variance, ATP: Adenosine triphosphate, CA: Cornu ammonis, CAT: Catalase, DG: Dentate gyrus, EDTA: Ethylenediamine tetra acetic acid, GR: Glutathione reductase, GSH: Glutathione reduced, HCl: Hydrochloric acid, IL-1β: Interleukin 1 beta, LPO: Lipid peroxidation, MDA: Malondialdehyde, NADPH: Nicotinamide adenine dinucleotide phosphate, PMS: post mitochondrial supernatant, SE: Status epilepticus, SEM: Standard error of the mean, SOD Superoxide dismutase, TBA: Thiobarbituric acid, TBARS: Thiobarbituric acid reactive substance, TLE: Temporal lobe epilepsy, TNF-α: Tumor necrosis factor alpha

Effects of Lycopene and Sodium Valproate on Pentylenetetrazol-Induced Kindling in Mice

Sodium valproate and tomato extract have been studied in different experimental models of epilepsy individually. The aim of the present study was to evaluate the effect of lycopene on the antiepileptic effects of sodium valproate against pentylenetetrazol-induced kindling in mice. Swiss albino mice of either sex were randomly divided into 5 groups, with each group containing 8 mice. These groups were treated with pentylenetetrazol (45 mg/kg on days 8, 10, and 12 and 70 mg/kg on day 14 day, i.p.); sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol; lycopene (2 mg/kg, p.o.) + sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol; and lycopene (4 mg/kg, p.o.) + sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol, for 14 days, respectively. After treatment, the animals were observed for 30 minutes for behavioral analysis. Subsequently, the animals were sacrificed, and their brain was removed for the biochemical estimations of thiobarbituric acid reactive substances, catalase, superoxide dismutase activity, reduced glutathione, and gamma-aminobutyric acid. Significant pentylenetetrazol-induced seizure was characterized by alteration in the seizure score and latency as well as a significant increase in the levels of brain thiobarbituric acid reactive substances and a significant decrease in reduced glutathione, catalase, superoxide dismutase, and gamma-aminobutyric acid levels. Treatment with sodium valproate and lycopene significantly restored the seizure score, latency, thiobarbituric acid reactive substance, reduced glutathione, catalase, superoxide dismutase, and gamma-aminobutyric acid levels near to normal compared to pentylenetetrazol. The present study provides experimental evidence that a combination therapy of lycopene along with sodium valproate attenuated seizure and oxidative stress against pentylenetetrazol-induced kindling in mice.

Anticonvulsant Effects of Lippia citriodora (Verbenaceae) Leaves Ethanolic Extract in Mice: Role of GABAergic System

Background:

Lippia citriodora Kunth is one of the Iranian traditional medicines for the treatment of convulsive disorders. The goal of this study is to investigate the anticonvulsant activity of the plant's leave ethanolic extract against electro- and chemoconvulsant-induced seizures in mice.

Methods:

The anticonvulsant activity of the extract (200, 400, 800 mg/kg, per os, p.o.) was investigated in pentylenetetrazole (PTZ) and maximal electroshock (MES)-induced seizures in mice. Diazepam (1 mg/kg) and phenytoin (25 mg/kg) intraperitoneally (i.p.) were used as reference drugs. In addition, for investigating the role of GABAergic system, flumazenil (2 mg/kg, i.p.) was also injected before L. citriodora.

Results:

The extract had not any toxicity and significantly decreased the duration and increased the latency of the seizures induced by PTZ (90 mg/kg). In the MES test, L. citriodora displayed statistically significant reduction in hind limb tonic extension duration in a nondose-dependent manner. Flumazenil reversed the anticonvulsant activity of the plant's extract in the PTZ model.

Conclusions:

The results propose that L. citriodora leave ethanolic extract has anticonvulsant activity against convulsive disorders. It seems that this plant's extract generates its antiseizure effect through GABAergic system potentiation. Further studies will be needed in order to investigate the exact mechanisms of it. Moreover, one may conclude that the present results are in accordance with the positive effect of L. citriodora extract to treat convulsion mentioned in old Iranian literature.

Natural terpenoids as a promising source for modulation of GABAergic system and treatment of neurological diseases

γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter reducing neural excitability in the mammalian central nervous system (CNS) with three subclasses of receptors. Several conventional drugs and compounds modulate the GABAergic system, demonstrating different pharmacological effects. In this review, interactions of natural terpenoids with the GABAergic system are highlighted with relation to disorders like anxiety, insomnia, convulsion, pain, and cognitive deficits. Terpenoids with various structures affect the function of the GABAergic system via dissimilar mechanisms. Most of the discussed compounds interact with GABA receptors, but especially with the GABAA subtype. This may be due to the fact that researchers tend to assess the interaction of compounds using GABAA receptors. However, bilobalide, a sesquiterpene, showed anticonvulsant properties through the activation of glutamic acid decarboxylase (GAD) enzyme, which is a key enzyme in biosynthesis of GABA. Therefore, further studies evaluating and comparing terpenoids of different classes and their interaction with the GABA system, along with their pharmacokinetic properties, could be worthwhile in future studies.

Anticonvulsant and antioxidant effects of Tilia americana var. mexicana and flavonoids constituents in the pentylenetetrazole-induced seizures

Tilia genus is commonly used around the world for its central nervous system properties; it is prepared as tea and used as tranquilizing, anticonvulsant, and analgesic. In this study, anticonvulsant activity of the Tilia americana var. mexicana inflorescences and leaves was investigated by evaluating organic and aqueous extracts (100, 300, and 600 mg/kg, i.p.) and some flavonoids in the pentylenetetrazole-induced seizures in mice. Moreover, antioxidant effect of these extracts and flavonoids was examined in an in vitro study by using spectrophotometric technique. Significant activity was observed in the methanol extract from inflorescences. An HPLC analysis of the methanol extract from inflorescences and leaves of Tilia allowed demonstrating the respective presence of some partial responsible flavonoid constituents: quercetin (20.09 ± 1.20 μg/mg and 3.39 ± 0.10 μg/mg), rutin (3.52 ± 0.21 μg/mg and 8.94 ± 0.45 μg/mg), and isoquercitrin (1.74 ± 0.01 μg/mg and 1.24 ± 0.13 μg/mg). In addition, significant but different antioxidant properties were obtained among the flavonoids and the extracts investigated. Our results provide evidence of the anticonvulsant activity of Tilia reinforcing its utility for central nervous system diseases whose mechanism of action might involve partial antioxidant effects due to the presence of flavonoids.

Is there a correlation between in vitro antioxidant potential and in vivo effect of carvacryl acetate against oxidative stress in mice hippocampus?

This study investigated in vitro and in vivo antioxidant potential of carvacryl acetate (CA), a derivative of carvacrol, monoterpenic component of oregano. The correlation between in vitro and in vivo CA effects was also determined. In vitro tests measured thiobarbituric acid reactive species content, nitrite formation and hydroxyl radical levels. In vivo tests measured thiobarbituric acid reactive species content, nitrite concentration and reduced glutathione (GSH) levels, as well as glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase activities were measured, using mice hippocampus. The CA administrations for in vivo tests were intraperitoneally and acutely improved. CA reduced lipid peroxidation, nitrite and hydroxyl radical contents in vitro as well as lipid peroxidation and nitrite content in vivo. It also increased reduced GSH levels and GPx as well as catalase activities. Moreover, CA required a lower concentration to inhibit 50 % of free radicals measured in vitro than trolox. There was significant negative correlation between in vitro nitrite levels and in vivo reduced GSH levels; in vitro nitrite content and in vivo GPx activity as well as in vitro hydroxyl radical levels and in vivo SOD activity. To date, this is the first study which suggests vitro and in vivo antioxidant potential to this monoterpene and the correlation between these parameters.

Trichosanthes tricuspidata modulates oxidative toxicity in brain hippocampus against pilocarpine induced status epilepticus in mice

Epilepsy prevails to be a neurological disorder in anticipation of safer drugs with enhanced anticonvulsant efficacy as presently available drugs fails to offer adequate control of epileptic seizures in about one-third of patients. The objective of this study was to evaluate the effect of Trichosanthes tricuspidata methanolic extract (TTME) against epilepsy mediated oxidative stress in pilocarpine induced mice. Intraperitonial administration of pilocarpine (85 mg/kg) induced seizure in mice was assessed by behavior observations, which is significantly (p < 0.05) reduced by TTME (100 and 200 mg/kg; i.p) in a dose dependant manner, similar to diazepam. Seizure was accompanied by significant increase in lipid peroxidation and the hippocampal nitrite content in pilocarpine group when compared with control. Moreover, the antioxidant enzymes superoxide dismutase, catalase and glutathione levels were decreased in pilocarpine administered groups. TTME administration attenuated oxidative damage as evident by decreased lipid oxidative damage and nitrite-nitrate content and restored the level of enzymatic antioxidant defenses in hippocampus. Involvement of free radicals during epilepsy is further confirmed by histopathological analysis which showed the loss of neuronal cells in hippocampus CA1 and CA3 pyramidal region. Our findings strongly support the hypothesis that TTME has anticonvulsant activity accompanied with the strong antioxidant potential plays a crucial role in reducing the oxidative stress produced by seizure.

Purple grape juices prevent pentylenetetrazol-induced oxidative damage in the liver and serum of Wistar rats

Oxidative damages in hepatocytes may be caused by epilepsy and/or anticonvulsant drugs. Epilepsy is one of the most common neurological disorders, characterized by recurrent seizures, which may increase the content of reactive oxygen species. Organic and conventional grape juices are rich in polyphenols, compounds with important antioxidant activity. It is hypothesized that organic and conventional purple grape juices may have protective effect against oxidative damage induced by pentylenetetrazole (PTZ) (a standard convulsant drug) in the liver and serum of Wistar rats. Animals (n = 16 in each group) received, by gavage, saline, organic grape juice or conventional grape juice (10 μL/g of body weight) for 17 days. Subsequently, half of the rats in each group received PTZ (60 mg/kg). After 30 minutes, the animals were euthanized by decapitation. Liver and blood samples were isolated to evaluate oxidative parameters (lipid and protein oxidation, nitric oxide metabolite content, antioxidant defenses, and protein sulfhydryl content). The results of this study showed that although organic juice contains higher polyphenol content than conventional juice, both juices conferred protection against lipid and protein oxidative damage and limited the increase in PTZ-induced nitric oxide metabolite content in the liver and serum. In addition, both juices inhibited the PTZ-induced reduction in enzymatic antioxidant defenses (superoxide dismutase and catalase activities) and sulfhydryl protein content in the liver and serum. In summary, both organic and conventional grape juices were able to reduce oxidative damage induced by PTZ in the liver and serum of Wistar rats.

Flavan-3-ol compounds prevent pentylenetetrazol-induced oxidative damage in rats without producing mutations and genotoxicity

Seizure disorder is a chronic condition in the brain that affects approximately 50 million people worldwide. Oxidative stress plays a crucial role in the pathophysiology of this disorder and can cause neuronal injury. Approximately one in three treated patients suffers from seizures regardless of pharmacological intervention, which results in oxidative damage. The present study aims to investigate the possible protective effect of antioxidant-rich Vitis labrusca extract on pentylenetetrazol-induced oxidative damage in Wistar rats. Possible behavioral alterations, genotoxic and mutagenic effects of the extract were also evaluated. The results showed that V. labrusca extract provides a significant protective effect against oxidative damage to lipids and proteins induced by pentylenetetrazol in the cerebral cortex, cerebellum, hippocampus and liver of rats. Also, the extract did not alter locomotor behavior. Moreover, it was non-genotoxic and non-mutagenic. Our results suggest the possibility of using V. labrusca extract as a therapeutic agent to minimize neuronal damage associated with seizures.

Anticonvulsant effect of phytol in a pilocarpine model in mice

The present study investigated the effects of phytol in pilocarpine-induced seizures. The latency for development of convulsions and mortality rate was recorded in this model using mice. The results revealed that phytol (25, 50 and 75 mg/kg, i.p.) increased latency to first seizure and decreased percentage of these seizures. Moreover, phytol also protected the animals against status epilepticus induced by pilocarpine, and decreased the mortality rate. Mice treated with pilocarpine (n=24) presented 100% of mortality during the first hour of observation. In turn, phytol-pretreated animals within 30 min before the administration of pilocarpine (400 mg/kg) remained alive during the first hour of observation. On the other hand, 6-8h after administration of pilocarpine it was observed that 10 (41.66%), 8 (33.33%) and 4 (16.66%) animals died (respectively). Thus, the pretreatment with phytol was able to block mortality rate during the first hour in acute phase of seizures, and significantly reduced this rate in a dose-dependent manner (p<0.05), suggesting an anticonvulsant effect. In addition, none of the phytol effects was blocked by pre-treatment with flumazenil, an antagonist of benzodiazepine receptors. In conclusion, phytol exhibits anticonvulsant activity by modulating of neurotransmitter systems, but further investigations are in progress to confirm this pharmacological property.

Evaluation of acute toxicity of a natural compound (+)-limonene epoxide and its anxiolytic-like action

The aim of the study is to determine the acute toxicity and anxiolytic-like effects of a mixture of cis and trans of (+)-limonene epoxide in animal models of anxiety. After acute treatment with (+)-limonene epoxide at doses of 25, 50 and 75 mg/kg (i.p.) no mortality was noted during 14 days of observation. In general, behavior, food and water consumption showed no significant changes. In open field test, (+)-limonene epoxide at doses of 25, 50 and 75 mg/kg, after intraperitoneal administration, significantly decreased the number of crossings, grooming and rearing (p<0.001). All these effects were reversed by the pre-treatment with flumazenil (25 mg/kg, i.p.), similar to those observed with diazepam used as a positive standard. In the elevated-plus-maze test, (+)-limonene epoxide increased the time of permanence and the number of entrances in the open arms. All these effects were reversed by flumazenil, an antagonist of benzodiazepine receptors. In addition, (+)-limonene epoxide (75 mg/kg) also produced a significant inhibition of the motor coordination (p<0.01), that was reversed by flumazenil. In conclusion, the present work evidenced sedative and anxiolytic-like effects of (+)-limonene epoxide, which might involve an action on benzodiazepine-type receptors. These results indicate that the properties of (+)-limonene epoxide should be more thoroughly examined in order to achieve newer tools for management and/or treatment of central nervous system diseases and anxiolytic-like effects. The LD50 obtained for the acute toxicity studies using intraperitoneal route of administration was 4.0 g/kg. These findings suggest that acute administration of the (+)-limonene epoxide exerts an anxiolytic-like effect on mice, and it could serve as a new approach for the treatment anxiety, since it practically does not produce toxic effects.

Anxiolytic-like effects of inhaled linalool oxide in experimental mouse anxiety models

Linalool oxide is a monoterpene that is found in some species of aromatic plants. The effects of the inhalation of linalool oxide (0.65%, 1.25%, 2.5% and 5.0% w/w) in the elevated plus-maze and light/dark box tests as animal models of anxiety were investigated in adult male mice and compared with the effects of the reference anxiolytic diazepam (0.5 and 2.0 mg/kg), administered intraperitoneally. Additionally, the effects of inhaled linalool oxide were investigated in the rotarod test. Linalool oxide significantly increased the number of visits to the open arms of the elevated plus-maze and the amount of time spent there as well as the total number of entries. In the light/dark box test, inhalation of linalool oxide led to an increase in the time spent by the mice in the brightly-lit chamber and in the number of times the animal crossed from one compartment to another. Performance on the rotarod was unaffected. Thus, inhaled linalool oxide was found to have anxiolytic properties in both animal models, without causing any motor deficit. These results suggest that inhalation of linalool oxide may be a useful means of counteracting anxiety.