Anticonvulsant properties of the methanolic extract of Cyperus articulatus (Cyperaceae)

Antimicrobial Activity on Streptococcus mutans and Enterococcus faecalis of Cyperus articulatus Ethanolic Extracts

Oral diseases are one of the biggest public health problems worldwide, caused by opportunistic pathogens such as Streptococcus mutans and Enterococcus faecalis. Cyperus articulatus (priprioca) is a plant conventionally used in traditional medicine in the Amazon region. However, little is known about the possible dentistry-related uses of extracts from the rhizomes and solid waste generated by the extraction of essential oils from this vegetable. This study aimed to investigate the chemical composition of volatile compounds and antimicrobial activity through the Minimum Inhibitory Concentration test (MIC and assessment of the toxicity by Hens Egg Test-Chorion Allantoic Membrane (HET-CAM) of the ethanolic extracts from Cyperus articulatus intact rhizomes and solid waste. We identified sesquiterpenes as the main constituents, strong antimicrobial activity of the ethanolic extract of intact rhizomes against S. mutans (MIC = 0.29 mg/mL), moderate antimicrobial activity against E. faecalis of the extract obtained from the solid waste (MIC = 1.17 mg/mL), and absence of toxicity for both tested extracts. The absence of irritation and the antibacterial activity of the ethanolic extract from C. articulatus rhizomes and solid waste reveal its potential for use in the alternative control of bacteria that cause oral infections and may present economic viability as a raw material for dental products.

Antibacterial activity and action mechanism of curcusionol from Carex siderosticta Hance against Ralstonia nicotianae

BACKGROUND

Tobacco bacterial wilt is a typical soil-borne disease caused by Ralstonia nicotianae, which causes huge losses in tobacco production every year. The crude extract of Carex siderosticta Hance was shown to have antibacterial activity against R. nicotianae during our search, and the natural antibacterial components were sought after using bioassay-guided fractionation of the compounds.

RESULT

Ethanol extract of Carex siderosticta Hance with the minimum inhibitory concentration (MIC) value of 100 μg/mL against R. nicotianae in vitro. The potential of these compounds as antibactericides against R. nicotianae were assessed. Curcusionol (1), showed the highest antibacterial activity against R. nicotianae with MIC value of 12.5 μg/mL in vitro. In the protective effect tests, the control effect of curcusionol (1) was 92.31 and 72.60%, respectively, after application of 7 and 14 days, at a concentration of 1500 μg/mL, being comparable to that of streptomycin sulfate at a concentration of 500 μg/mL, confirming that curcusionol (1) showed the potential for the development of new antibacterial drugs. RNA-sequencing, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis confirmed that curcusionol mainly destroys R. nicotianae cell membrane structure and affects quorum sensing (QS) to inhibit pathogenic bacteria.

CONCLUSION

This study revealed that the antibacterial activity of Carex siderosticta Hance makes it a botanical bactericide against R. nicotianae, while curcusionol as lead structures for antibacterial development is obvious by its potent antibacterial activity. © 2023 Society of Chemical Industry.

The Role of the NMDA Receptor in the Anticonvulsant Effect of Ellagic Acid in Pentylenetetrazole-Induced Seizures in Male Mice

Methods

In this experimental study, 64 mice were divided into 8 groups and received the following: normal saline; EA at doses of 6.25, 12.5, and 25 mg/kg; NMDA agonist at a dose of 75 mg/kg; NMDA antagonist (ketamine) at a dose of 0.5 mg/kg; an effective dose of EA plus NMDA agonist; and a subeffective dose of EA plus ketamine. We induced seizure using intravenous administration of PTZ. 60 minutes before induction of seizure, drugs were administrated. Duration lasts to seizure-induced was measured. Finally, the gene expression of NMDA receptor subunits (Nr2a and Nr2b) was assessed in the prefrontal cortex.

Results

Results showed that EA increased the seizure threshold and decreased the expression of Nr2a and Nr2b. We determined that ketamine potentiated and NMDA attenuated the effects of subeffective and effective doses of EA.

Conclusion

EA probably via attenuation of the NMDA-R pathway possesses an anticonvulsant effect in PTZ-induced seizure in mice.

Intake of Natural, Unprocessed Tiger Nuts (Cyperus esculentus L.) Drink Significantly Favors Intestinal Beneficial Bacteria in a Short Period of Time

Horchata is a natural drink obtained from tiger nut tubers (Cyperus esculentus L.). It has a pleasant milky aspect and nutty flavor; some health benefits have been traditionally attributed to it. This study evaluated the effects of an unprocessed horchata drink on the gut microbiota of healthy adult volunteers (n = 31) who consumed 300 mL of natural, unprocessed horchata with no added sugar daily for 3 days. Although there were no apparent microbial profile changes induced by horchata consumption in the studied population, differences could be determined when volunteers were segmented by microbial clusters. Three distinctive enterogroups were identified previous to consuming horchata, respectively characterized by the relative abundances of Blautia and Lachnospira (B1), Bacteroides (B2) and Ruminococcus and Bifidobacterium (B3). After consuming horchata, samples of all volunteers were grouped into two clusters, one enriched in Akkermansia, Christenellaceae and Clostridiales (A1) and the other with a remarkable presence of Faecalibacterium, Bifidobacterium and Lachnospira (A2). Interestingly, the impact of horchata was dependent on the previous microbiome of each individual, and its effect yielded microbial profiles associated with butyrate production, which are typical of a Mediterranean or vegetable/fiber-rich diet and could be related to the presence of high amylose starch and polyphenols.

New Insights Into the Anticonvulsant Effects of Essential Oil From Melissa officinalis L. (Lemon Balm)

Melissa officinalis L. is used in traditional European and Iranian folk medicines to treat a plethora of neurological diseases including epilepsy. We utilized the in vitro and in vivo models of epilepsy to probe the anticonvulsant potentials of essential oil from M. officinalis (MO) to gain insight into the scientific basis for its applications in traditional medicine for the management of convulsive disorders. MO was evaluated for effects on maximal electroshock (MES) and pentylenetetrazole (PTZ) -induced seizures in mice, on 4–aminopyridine (4-AP)-brain slice model of epilepsy and sustained repetitive firing of current clamped neurons; and its ameliorative effects were examined on seizure severity, anxiety, depression, cognitive dysfunction, oxidative stress and neuronal cell loss in PTZ-kindled rats. MO reversibly blocked spontaneous ictal-like discharges in the 4-AP-brain slice model of epilepsy and secondary spikes from sustained repetitive firing, suggesting anticonvulsant effects and voltage-gated sodium channel blockade. MO protected mice from PTZ– and MES–induced seizures and mortality, and ameliorated seizure severity, fear-avoidance, depressive-like behavior, cognitive deficits, oxidative stress and neuronal cell loss in PTZ–kindled rats. The findings warrant further study for the potential use of MO and/or its constituent(s) as adjunctive therapy for epileptic patients.

Phytochemistry and pharmacological activity of the genus artemisia

Artemisia and its allied species have been employed for conventional medicine in the Northern temperate regions of North America, Europe, and Asia for the treatments of digestive problems, morning sickness, irregular menstrual cycle, typhoid, epilepsy, renal problems, bronchitis malaria, etc. The multidisciplinary use of artemisia species has various other health benefits that are related to its traditional and modern pharmaceutical perspectives. The main objective of this review is to evaluate the traditional, modern, biological as well as pharmacological use of the essential oil and herbal extracts of Artemisia nilagirica, Artemisia parviflora, and other allied species of Artemisia. It also discusses the botanical circulation and its phytochemical constituents viz disaccharides, polysaccharides, glycosides, saponins, terpenoids, flavonoids, and carotenoids. The plants have different biological importance like antiparasitic, antimalarial, antihyperlipidemic, antiasthmatic, antiepileptic, antitubercular, antihypertensive, antidiabetic, anxiolytic, antiemetic, antidepressant, anticancer, hepatoprotective, gastroprotective, insecticidal, antiviral activities, and also against COVID-19. Toxicological studies showed that the plants at a low dose and short duration are non or low-toxic. In contrast, a high dose at 3 g/kg and for a longer duration can cause toxicity like rapid respiration, neurotoxicity, reproductive toxicity, etc. However, further in-depth studies are needed to determine the medicinal uses, clinical efficacy and safety are crucial next steps.

Non-clinical toxicity of (+)-limonene epoxide and its physio-pharmacological properties on neurological disorders

The compound (+)-limonene epoxide has antioxidant, anxiolytic, and antihelminthic properties. However, investigations to determine its long-term exposure were not performed. We investigated the systemic toxicological profile after chronic exposure as well as the antidepressant and antiepileptic potentialities of (+)-limonene epoxide on mice. Initially, we evaluated acute toxicity on Artemia salina nauplii and cytotoxicity on mice erythrocytes and peripheral blood mononuclear cells (PBMC). Aftterwards, mice were chronically treated for 120 days by gavage with (+)-limonene epoxide (25, 50, and 75 mg/kg/day) and this exposure was assessed by pathophysiological measurements. For antidepressant and anticonvulsivant analysis, we performed the forced swimming and tail suspension protocols and pentylenetetrazol- and picrotoxin-induced seizures, respectively. (+)-Limonene epoxide showed a LC50 value of 318.7 μg/mL on A. salina shrimps, caused lysis of red blood cells at higher concentrations only but did not show cytotoxicity on PMBC, which suggests pharmacological safety if plasma concentrations do not exceed 100 μg/mL. Macroscopic, hematological, clinical chemistry, and nutritional changes were not detected, though focal areas of hepatic necrosis, inflammatory infiltrate, and karyolysis have been detected at 75 mg/kg/day. The compound inhibited the developing of pentylenetetrazol- and picrotoxin-induced seizures, decreased deaths, and reduced immobility times, mainly at 75 mg/kg. So, it reversed reserpine effects, suggesting antidepressant effects should be linked to serotonergic and/or adrenergic transmission. It is feasible that (+)-limonene epoxide plays a benzodiazepine-like anticonvulsive action and may be also recommended as an antidote for poisonings caused by central depressants.

Synthesis and Biological Evaluation of Amino Acid Based Mutual Amide Prodrugs of Phenytoin as Anticonvulsant Agents

BACKGROUND

Phenytoin (5,5-diphenyl hydantoin) has poor water solubility, which results in incomplete oral availability. Other problems associated with the oral and intramuscular administration of phenytoin are gastric irritation and inflammation at the site of injection.

OBJECTIVE

The purpose of this study was to synthesize mutual amide prodrugs of phenytoin by using amino acids like glycine, L-tryptophan, L-lysine and taurine.

METHODS

These prodrugs were synthesized and characterized by Fourier Transform Infrared (FTIR), Proton nuclear magnetic resonance (1H NMR) and Mass Spectra. Physical and spectral characterization was performed by determination of solubility, maximum wavelength, partition coefficient (log P), ionization constant (pKa), specific (α) and molar rotation (μ), refractive index (n), specific refraction (RS) and molar refraction (RM).

RESULTS

The results obtained from solubility and log P values determination indicated that phenytoin prodrugs can be administered by oral as well as a parenteral route by minimizing the limitations associated with phenytoin. Anticonvulsant activity of prodrugs (4a-4d) was evaluated by using maximal electroshock (MES) and strychnine induced seizure test on albino mice of either sex weighing 25-30 g in which 4b and 4d were found to have significant anticonvulsant activity for MES and strychnine induced seizure test. In vitro enzymatic hydrolysis study of 4b and 4d was performed on liver, intestinal mucosa and plasma sample of male Sprague Dawley rats weighing 280-300 g in which phenytoin was eluted at 10.13 to 10.68 minutes at 220 nm.

CONCLUSION

The results obtained from the present work showed that amino acid-based mutual prodrug strategy can be a promising method to increase the solubility and anticonvulsant activity of phenytoin for the development of anticonvulsant agents.

Chemical Composition and In Vitro Antiplasmodial Activity of the Ethanolic Extract of Cyperus articulatus var. nodosus Residue

Cyperus articulatus L. is popularly known as priprioca. Its rhizomes are used as a medicine in the treatment of malaria in traditional medicine. Since priprioca oil is extracted for commercial purpose, we evaluated if the components from the priprioca residue can be a source of antiplasmodial active molecules. This study aimed to determine the in vitro antiplasmodial and cytotoxicity activities of the ethanolic extract of C. articulatus as an in vitro antiplasmodial agent. From the solid residue of the plant rhizomes, 40 g samples were removed and subjected to hot extraction using a Soxhlet extractor. The in vitro antiplasmodial activity was determined using the W2 and 3D7 strains of P. falciparum. The phytochemical study identified the following main compounds: corymbolone (14.25%), cyclocolorenone (9.75%), and cadalene (8.36%). The extract exhibited moderate IC₅₀ (inhibitory concentration) against the two strains of P. falciparum: 1.21 ± 0.01 against the W2 strain and 1.10 ± 0.06 µg/mL against the 3D7 strain. Our results show the therapeutic potential of priprioca residue as a low-cost antiplasmodial agent.

Synthesis and Evaluation of Anticonvulsant Activity of Some Schiff Bases of 7-Amino-1,3-dihydro-2H-1,4-benzodiazepin-2-one

A variety of 1,3-dihydro-2H-1,4-benzodiazepin-2-one azomethines and 1,3-dihydro-2H-1,4-benzodiazepin-2-one benzamide were prepared, characterized and evaluated for the anticonvulsant activity in the rat using picrotoxin-induced seizure model. The prepared 1,3-dihydro-2H-1,4-benzodiazepin-2-one azomethine derivatives emerged potentially anticonvulsant molecular scaffolds exemplified by compounds, 7-{(E)-[(4-nitrophenyl)methylidene]amino}-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one, 7-[(E)-{[4-(dimethylamino)phenyl]methylidene}amino]-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one, 7-{(E)-[(4-bromo-2,6-difluorophenyl)methylidene]amino}-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one and 7-[(E)-{[3-(4-fluorophenyl)-1-phenyl-1H-pyrazol-4-yl]methylidene}amino]-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one. All these four compounds have shown substantial decrease in the wet dog shake numbers and grade of convulsions with respect to the standard drug diazepam. The most active compound, 7-[(E)-{[4-(dimethylamino)phenyl]methylidene}amino]-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one, exhibited 74 % protection against convulsion which was higher than the standard drug diazepam. Furthermore, to identify the binding mode of the interaction amongst the target analogs and binding site of the benzodiazepine receptor, molecular docking study and molecular dynamic simulation were carried out. Additionally, in silico pharmacokinetic and toxicity predictions of target compounds were carried out using AdmetSAR tool. Results of ADMET studies suggest that the pharmacokinetic parameters of all the target compounds were within the acceptable range to become a potential drug candidate as antiepileptic agents.

Seizing the moment: Zebrafish epilepsy models

Zebrafish are now widely accepted as a valuable animal model for a number of different central nervous system (CNS) diseases. They are suitable both for elucidating the origin of these disorders and the sequence of events culminating in their onset, and for use as a high-throughput in vivo drug screening platform. The availability of powerful and effective techniques for genome manipulation allows the rapid modelling of different genetic epilepsies and of conditions with seizures as a core symptom. With this review, we seek to summarize the current knowledge about existing epilepsy/seizures models in zebrafish (both pharmacological and genetic) and compare them with equivalent rodent and human studies. New findings obtained from the zebrafish models are highlighted. We believe that this comprehensive review will highlight the value of zebrafish as a model for investigating different aspects of epilepsy and will help researchers to use these models to their full extent.

Zebrafish bioassay-guided isolation of antiseizure compounds from the Cameroonian medicinal plant Cyperus articulatus L

BACKGROUND

Epilepsy is a chronic neurological disorder affecting more than 50 million people worldwide, of whom 80% live in low- and middle-income countries. Due to the limited availability of antiseizure drugs (ASDs) in these countries, medicinal plants are the first-line treatment for most epilepsy patients. In Cameroon, a decoction of Cyperus articulatus L. rhizomes is traditionally used to treat epilepsy.

PURPOSE

The aim of this study was to identify and isolate the active compounds responsible for the antiseizure activity of C. articulatus in order to confirm both its traditional medicinal usage and previous in vivo studies on extracts of this plant in mouse epilepsy models.

METHODS

The dried rhizomes of C. articulatus were extracted with solvents of increasing polaritie (hexane, dichloromethane, methanol and water). A traditional decoction and an essential oil were also prepared. These extracts were evaluated for antiseizure activity using a larval zebrafish seizure model with seizures induced by the GABAA antagonist pentylenetetrazole (PTZ). The hexane extract demonstrated the highest antiseizure activity and was therefore selected for bioassay-guided fractionation. The isolated bioactive compounds were characterized by classical spectroscopic methods. Since they were found to be volatile, they were quantified by GC-FID. In addition, the absorption of the active compounds through the gastrointestinal tract and the blood-brain barrier was evaluated using a hexadecane and a blood-brain barrier parallel artificial membrane permeability assays (HDM-PAMPA and PAMPA-BBB).

RESULTS

The hexane extract of C. articulatus exhibited the highest antiseizure activity with a reduction of 93% of PTZ-induced seizures, and was therefore subjected to bioassay-guided fractionation in order to isolate the active principles. Four sesquiterpenoids were identified as cyperotundone (1), mustakone (2), 1,2-dehydro-α-cyperone (3) and sesquichamaenol (4) and exhibited significant antiseizure activity. These volatile compounds were quantified by GC in the hexane extract, the essential oil and the simulated traditional decoction. In addition, the constituents of the hexane extract including compounds 1 and 2 were found to cross the gastrointestinal barrier and the major compound 2 crossed the blood-brain barrier as well.

CONCLUSION

These results highlight the antiseizure activity of various sesquiterpene compounds from a hexane extract of C. articulatus dried rhizomes and support its use as a traditional treatment for epilepsy.

Awareness and current knowledge of epilepsy

Epilepsy is a severe neural disorder that affects approximately fifty million individuals globally. Despite the fact that for most of the people with epilepsy, convulsions are better controlled by current accessible antiepileptic medicines, yet there are more than 30% of individuals affected with medically intractable epilepsy and around 30-40% of all patients with epilepsy affected by many adverse reactions and convulsion resistance to the present antiepileptic drugs. Consequently, various scientists attempt to develop new strategies to treat epilepsy, for instance, to find out novel antiepileptic ingredients from traditional medicines. This work aims to present a complete summary of natural medicines prescribed as antiepileptic agents all over the world by ethnic groups and different tribes. We undertook an extensive bibliographic analysis by searching peer reviewed papers and classical textbooks and further consulting well accepted worldwide scientific databases. We carried out PubMed, EMbase and CENTRAL searches by means of terms such as "antiepileptic" and "anti-convulsant" activity of plants. Medicinal plants have been prescribed to treat epilepsy and have been recognized as antiepileptic medicines. In this review, a variety of herbs have been reviewed for thorough studies such as Cuminum cyminum, Butea monosperma, Solanum americanum, Anacyclus pyrethrum, Leonotis leonurus, Elaeocarpus ganitrus and Angelica archangelica. This paper shows that it was high time experimental studies are increased to obtain novel potential active principles from medicinal plants. Plant extracts and their chemical constituents should be further evaluated to clarify their mechanisms of action. This paper provides a solid base upon which to further investigate the clinical efficacy of medicinal plants that are both currently prescribed by physicians as traditional antiepileptic agents, but also could be effective as an antiepileptic drug with further research and study.

Medicinal Plants Combating Against Insomnia: A Green Anti-Insomnia Approach

Insomnia is a state defined as trouble with sleep; it is a chronically disabling condition and is now significantly prevalent, imposing enormous health and economic burdens both on individuals and on society. This state includes trouble in falling asleep, problems staying asleep, fragmented sleep (repeatedly awakening at night), and/or awakening before time in the morning. This difficulty in sleeping causes feeling exhausted during the day and trouble with daytime activities including driving, family responsibilities, and completion of valued daily routines. Different types of synthetic sedative drugs are used to handle nervous system changes, but repeated use of sedatives caused tolerance in the human body. After a while, people had to take a heavy dose of sedative to make them feel sleepy, which imposes extra toxic effects on vital organs of the body. Medicinal plants are gaining more and more attention as sedative agents because herbs contained different types of natural bioactive metabolites with not well reported side effects. In addition, medicinal plants have economic, high efficacy and are easy available. So in current review plants possessing sedative activities have been compiled with their constituents responsible to manage insomnia. Review of the literature indicated that medicinal plants from various systems of medicine have been reported to possess sedative activity. This review suggests that medicinal plants are efficacious for insomnia; further laboratory and clinical studies are required.

Herbal medicine for epilepsy seizures in Asia, Africa and Latin America: A systematic review

RELEVANCE

More than 70 million people suffer epilepsy worldwide. Low availability of anti-epileptic drugs, side-effects and drug-resistant epilepsy affect the quality of life of persons with epilepsy in countries with a poorly developed health system. Herbal medicine is frequently used for this neurological condition.

OBJECTIVES

The main objective was to provide a detailed analysis of Herbal Medicine used for neurological conditions related with epilepsy in Asia, Africa and Latin America. More broadly, this study aims to highlight species with assessed efficacy (cross-cultural use, pharmacological effects on models of epileptic seizures) and safety (toxicological data in laboratory) information, in order to point out species of interest for further studies. A critical assessment of models used in pharmacological evaluations was done.

MATERIALS AND METHODS

The systematic search for Herbal Medicine treatments for epilepsy was performed considering all the articles published until February 2017 through three scientific databases. It was made with MeSH terms and free text defining the epilepsy seizures and plant species. We included studies carried out in Asia, Africa and Latin America. All articles reporting the use of Herbal Medicine to treat epilepsy seizures and/or their pharmacological evaluation were retained for further analysis.

RESULTS

The search yielded 1886 articles, from 30 countries. Hundred and six articles published between 1982 and 2017 were included, corresponding to a total of 497 use reports for 351 plant species belonging to 106 families. Three hundred and seventy seven use reports corresponding to 264 species in ethnopharmacological surveys and 120 evaluation reports corresponding to 107 species were noted. Twenty-nine reports, for 29 species, combined both ethnopharmacological and pharmacological evaluation. Fifty eight studies originated from Africa, 35 studies from Asia and 18 from Latin America. Highest use report was noted for rhizomes of Acorus calamus L. (12 use report in 1 country) and leaves of Bacopa monnieri (L.) Wettst. (8 use report in 2 countries). Therefore these species display the highest use convergence. Regarding pharmacological evaluation most studied species were: Leonotis leonurus (L.) R.Br. (4 evaluation reports in 1 country), Uncaria rhynchophylla (Miq.) Miq. ex Havil. (3 evaluation reports in 2 countries) and Calotropis gigantea (L.) Dryand. (3 evaluation reports in 1 country). In vivo models of chronic epilepsy were more relevant than in vitro models or chemical models inducing acute seizures for pharmacological assessment.

CONCLUSION

Species with the highest use report were not those with pharmacological evaluation. It will be pertinent to assess the pharmacological effects and safety of medicinal plants used mostly by traditional healers on predictive models of seizures.

Neuroprotective Effect of Coumarin Nasal Formulation: Kindling Model Assessment of Epilepsy

Epilepsy is a brain disorder characterized by sudden recurrent seizures. Considering the fact that epileptogenesis is a process that affects the quality of life, our goal is to delay the process of epileptogenesis and to increase the latency of epileptic attacks, offering better quality of life to patients. Traditional system of medicines has a promise in some of the medicines, which have been used for the treatment of epilepsy. One such medicinal plant is Eclipta alba (EA). According to Ayurvedic philosophy, the juice of leaves of EA is pounded with garlic and pepper for the treatment of epilepsy. Taking clue from the Ayurvedic system of medicines, we formulated coumarin fraction of EA, namely, coumarin nasal formulation (CNF) for its nasal delivery. CNF was analyzed by using high performance liquid chromatography (HPLC) and ultraviolet absorption spectroscopy for its drug content determination. In vitro drug release studies were performed in simulated nasal electrolyte solution (SNES) maintaining constant pH of 5.5 at 37°C. Irritation by CNF was evaluated using hen's egg test chorioallantoic membrane (HET-CAM) assay. Formulation was found to be non-irritant in HET-CAM assay. CNF was further assessed in vivo by measuring the progress and attainment of pentylenetetrazole (PTZ) kindling in mice. Neuronal changes were assessed by hematoxylin and eosin (H&E) and Nissl staining technique. Glial fibrillary acidic protein (GFAP) a neuroinflammatory marker and tumor necrosis factor alpha (TNF-α) an inflammatory marker were also measured. CNF (10 mg/kg, nasal route) when given as a pretreatment lowered seizure score and delayed the progression of seizure similar to diazepam. CNF decreased the PTZ induced oxidative damage, TNF-α as well as GFAP levels in the midbrain tissue particularly in hippocampus region. The results suggest that CNF may be a promising therapeutic approach to offer protection from sudden recurrent seizures alone or in combination with current drugs in management of epilepsy.

Neurochemical properties of neurospheres infusion in experimental-induced seizures

Cell replacement through neural stem cells has been a promising alternative therapy for neurodegenerative diseases. It was evaluated the possible protect and/or prevent role of neurospheres in experimental models of epilepsy by the use of biomarkers of oxidative stress and histopathological analysis. After 1 h of the epileptic inductions by pilocarpine, pentylenotetrazole and picrotoxin, rats were infused with a suspension of 2 × 10⁶ cells/0.25 mL, marked with Qtracker® 655, via caudal vein. In the control group epilepsy was not induced, but received the cell infusion under the same conditions of other groups. After 30 days, the rats were euthanized, and the removal of the brain was proceeded to later perform the assays oxidative stress and histopathology analysis. Thiobarbituric acid and nitrite levels were elevated in epileptic groups treated with neurospheres, and the levels of reduced glutathione, superoxide dismutase and catalase were reduced when compared to non-treated groups. The performance of oxidative enzymes from pilocarpine group treated with neurospheres showed slight increase. Histopathological evaluation observed distribution of neurospheres throughout the brain tissue, with viable cells and in process of differentiation in the pilocarpine group, but with differentiation and regeneration compromised in epilepsy by picrotoxin and pentylenetetrazole due to a microenvironment of oxidative stress. Neural stem cell therapy has a promising potential for protection in the pilocarpine epilepsy model, suggesting that the antioxidant system of neurospheres could reduce oxidative damage generated by seizure.

Review on medicinal plants and natural compounds as anti-Onchocerca agents

Onchocerciasis is a filarial vector borne disease which affects several million people mostly in Africa. The therapeutic approach of its control was based on a succession of drugs which always showed limits. The last one: ivermectin is not the least. It was shown to be only microfilaricidal and induced resistance to the human parasite Onchocerca volvulus. The approach using medicinal plants used in traditional medicine is a possible alternative method to cure onchocerciasis. Onchocerca ochengi and Onchocerca gutturosa are the parasite models used to assess anthelmintic activity of potentially anthelmintic plants. Numerous studies assessed the in vitro and/or in vivo anthelmintic activity of medicinal plants. Online electronic databases were consulted to gather publications on in vitro and in vivo studies of anti-Onchocerca activity of plants from 1990 to 2017. Globally, 13 plant families were investigated for anti-Onchocerca activity in 13 studies. The most active species were Anacardium occidentale, Euphorbia hirta and Acacia nilotica each with an LC₅₀ value of 2.76, 6.25 and 1.2 μg/mL, respectively. Polycarpol, voacamine, voacangine, ellagic acid, gallic acid, gentisic acid, 3-O-acetyl aleuritolic acid and (-)-epigallocatechin 3-O-gallate were the isolated plant compounds with anti-Onchocerca activity. Most of the assessed extract/compounds showed a good safety after in vivo acute toxicity assays and/or in vitro cytotoxicity test. The exception was the ethanol extract of Trichilia emetica, which killed completely and drastically mice at a dose of 3000 mg/kg. Several plant groups of compounds were shown active against Onchocerca sp. such as tannins, alkaloids, triterpenoids and essential oils. Nevertheless, none of the active compounds was subjected to clinical trial, to assessment of its diffusibility through nodular wall or its capability to induce genetic resistance of Onchocerca sp.

Anticonvulsant effect of ethanolic extract of Cyperus articulatus L. leaves on pentylenetetrazol induced seizure in mice

Cyperus articulatus (CA) rhizomes have demonstrated different properties on nervous system. However, the leaves still have not studied to treat epilepsy. The aim of this study was to determine the effect of CA ethanolic extract on pentylenetetrazol (PTZ) induced seizures in mice as well as measuring its antioxidant activity in vivo and in vitro. Mice were divided into five groups: (1) control (PTZ 80 mg/kg; i.p.), (2) PTZ-Diazepam (1 mg/kg; i.p.), (3-5) PTZ-CA 50, PTZ-CA 150 and PTZ-CA 300 (50, 150 and 300 mg/kg of CA extract, 30 min prior to each PTZ injection). The PTZ-CA 150 group showed lower seizure scores (P < 0.01), latency (P < 0.01), frequency (P < 0.01) and duration (P < 0.01) than control group. The antioxidant activity of CA extract scavenged DPPH radical showed IC 50 = 16.9 ± 0.1 μg/mL and TEAC = 2.28 ± 0.08, mmol trolox/g of extract, the content of gamma amino butyric acid (GABA) and malondialdehyde (MDA) were significantly high (P < 0.01) at dose of 150 mg/kg (82 ± 1.2 ng/g tissue; 1.0 ± 2.2 mol/g tissue, respectively). The present research demonstrated that CA extract possesses a potential effect to prevent PTZ induced seizures, antioxidant activity in addition to increase GABA levels.

Anti-Onchocerca activity and phytochemical analysis of an essential oil from Cyperus articulatus L

BACKGROUND

The lack of a safe and effective adult worm drug and the emergence of resistant animal parasite strains to the only recommended drug, the microfilaricide, ivermectin put many at risk of the devastating effects of the onchocerciasis. The present study was undertaken to investigate the acclaimed anti-Onchocerca activity of the roots/rhizomes of Cyperus articulatus in the traditional treatment of onchocerciasis in North Western Cameroon and to assess the plant as a new source of potential filaricidal lead compounds.

METHODS

Crude extracts were prepared from the dried plant parts using hexane, methylene chloride and methanol. The antifilarial activity was evaluated in vitro on microfilariae (Mfs) and adult worms of the bovine derived Onchocerca ochengi, a close relative of Onchocerca volvulus. The viabilities of microfilariae and adult male worms were determined based on motility reduction, while for the adult female worms the viability was based on the standard MTT/formazan assay. Cytotoxicity of the active extract was assessed on monkey kidney epithelial cells in vitro and the selectivity indices (SI) were determined. Acute toxicity of the promising extract was investigated in mice. Chemical composition of the active extract was unraveled by GC/MS analysis.

RESULTS

Only the hexane extract, an essential oil exhibited anti-Onchocerca activity. The oil killed both the microfilariae and adult worms of O. ochengi in a dose manner dependently, with IC50s of 23.4 μg/ml on the Mfs, 23.4 μg/ml on adult male worms and 31.25 μg/ml on the adult female worms. Selectivity indices were 4, 4, and 2.99 for Mfs, adult males and adult females, respectively. At a single limit dose of 2000 mg/kg body weight, none of 6 mice that received the essential oil by gavage died. GC/MS analysis revealed the presence of terpenoids, hydrocarbons and fatty acids or fatty acid derivatives as components of the oil.

CONCLUSIONS

The essential oil from the roots/rhizomes of Cyperus articulatus is active against O. ochengi microfilariae and adult worms in vitro in a dose dependent manner, hence may provide a source of new anti-filarial compounds. The results also support the traditional use of C. articulatus in the treatment of human onchocerciasis.

Behavioral and anticonvulsant effects of the standardized extract of Ficus platyphylla stem bark

ETHNOPHARMACOLOGICAL RELEVANCE

Decoctions of Ficus platyphylla Del.-Holl (Family: Moraceae) are used in Nigeria׳s folk medicine for the management of epilepsy and their efficacies are widely acclaimed among the rural communities of northern Nigeria. The aim of the study is to examine the behavioral and anticonvulsant properties of the standardized methanol extract of Ficus platyphylla (FP) stem bark, in order to scientifically describe its potential values in the management of convulsive disorders.

MATERIALS AND METHODS

High performance liquid chromatography (HPLC) and preliminary phytochemical analysis of the methanol extract were utilized and the intraperitoneal median lethal dose (LD50) determined in mice. The effects of FP were investigated on some murine models of behavior and its anticonvulsant effects studied on pentylenetetrazole (PTZ)-, strychnine (STN)-, picrotoxin (PCT)-, isoniazid (INH)-, aminophylline (AMI)- and maximal electroshock (MES)-induced seizures in mice.

RESULTS

The intraperitoneal oral LD50 of FP was estimated to be 5000mg/kg. FP significantly reduced the locomotor activities including the total distance covered, speed, active time and rearing counts. It shortened the onset and prolonged the duration of diazepam-induced sleep, but had no effect on motor coordination on the rota-rod treadmill or beam-walking assay in mice at the doses tested. The extract protected the mice against PTZ- and STN-induced seizures and significantly delayed the latencies of myoclonic jerks and tonic seizures induced by all the standard convulsant agents (PTZ, PCT, INH, STN and AMI) used in this study, but failed to protect the mice against MES seizures at the doses tested. The HPLC fingerprint of the extract shows a spectrum profile characteristic of Ficus platyphylla, while the preliminary phytochemical screening revealed the presence of saponins, flavonoids and tannins.

CONCLUSION

Our study provides scientific evidence that FP may contain psychoactive principles with potential anticonvulsant properties, thus supporting further development of the psychoactive components of this plant as anticonvulsant agents.

Discovery of anxiolytic 2-ferrocenyl-1,3-thiazolidin-4-ones exerting GABAA receptor interaction via the benzodiazepine-binding site

Herein, we report on the synthesis, spectral, crystallographic and electrochemical properties of a small library of N-substituted 2-ferrocenyl-1,3-thiazolidin-4-ones, designed as novel GABAA benzodiazepine-binding site ligands. The anxiolytic properties of the title compounds were evaluated in several different in vivo models, whereas the involvement of the GABAA receptor complex in the activity of the most potent compound, 2-ferrocenyl-3-(4-methoxyphenylethyl)-1,3-thiazolidin-4-one, was inferred from experiments with known GABAA-targeting agents. Ligand docking experiments revealed that the high, dose-dependent, anxiolytic activity of the new compounds might be due to their favorable interactions with the benzodiazepine-binding site of the GABAA receptor complex. The incorporation of the ferrocene core and fine tuning of the distance between the thiazolidinone core and an additional aromatic ring were judged to be crucial structural requirements for the observed anxiolytic effect.

Psychopharmacological properties of saponins from Randia nilotica stem bark

CONTEXT

Decoctions of Randia nilotica Stapf. (Rubiaceae) have been used in the Nigerian traditional medicine for the management of epilepsy, anxiety, depression and psychosis for many years and their efficacies are widely acclaimed among the rural communities of Northern Nigeria.

OBJECTIVE

The aim of this study is to establish whether the saponins present in R. nilotica are responsible for its acclaimed beneficial effects in Nigerian traditional medicine.

MATERIALS AND METHODS

The behavioural properties of the saponin-rich fraction (SFRN) of R. nilotica stem bark were studied on hole-board, diazepam-induced sleep, rota-rod and beam-walking in mice. The anticonvulsant properties of SFRN were also examined on maximal electroshock, pentylenetetrazole- and strychnine-induced seizures in mice.

RESULTS

The intraperitoneal LD₅₀ of SFRN in mice and rats were estimated to be 11.1 and 70.7 mg/kg, respectively. SFRN significantly prolonged the duration of diazepam-induced sleep; diminished head dip counts in the hole-board test and protected mice against maximal electroshock seizures. SFRN failed to protect mice against pentylenetetrazole- and strychnine-induced seizures; and had no effect on motor coordination on the rota-rod treadmill at the doses tested. SFRN significantly decreased the number of foot slips in the beam-walking assay in mice with no effect on time to reach the goal box.

DISCUSSION AND CONCLUSION

This study provides evidence of the psychopharmacological effects of SFRN, thus supporting further development of the psychoactive components as remedies for epilepsy.

The anticonvulsant and sedative effects of Gladiolus dalenii extracts in mice

Gladiolus dalenii Van Geel is a medicinal plant commonly used in traditional medicine in Africa to treat epilepsy and many other diseases. Two in vivo mouse models (maximal electroshock and pentylenetetrazol-induced convulsions) were used to evaluate the anticonvulsant activities of the plant extracts. Diazepam-induced sleep was used for the evaluation of the sedative properties. The macerated extract of G. dalenii protected 100 and 83.3% of mice against PTZ- and MES-induced seizures, respectively. The aqueous extract of G. dalenii protected 100 and 83.3% of mice against PTZ- and MES-induced seizures, respectively. The lyophilized extract of G. dalenii also protected 100 and 83.3% of mice against PTZ- and MES-induced seizures, respectively. The coadministration of G. dalenii with diazepam resulted in an additive effect, while the coadministration of G. dalenii with flumazenil or FG7142 resulted in antagonistic effects. The macerate of G. dalenii also exerted sedative activity by reducing the latency time to sleep and increasing the total duration of sleep induced by diazepam. The sleeping time increased from 16±3min in the control group to 118±11min at a dose of 150mg/kg of G. dalenii. The effects of G. dalenii suggested the presence of anticonvulsant and sedative activities that might show efficacy against secondarily generalized tonic-clonic seizures and primary generalized seizures and insomnia in humans.

Effect of Gentiana olivieri on experimental epilepsy models

BACKGROUND

Flowering herbs of Gentiana olivieri Griseb. (Gentianaceae) are widely used as bitter tonic, stomachic, stimulant of appetite, antipyretic, anticonvulsant, antidiabetic and for mental problems in the different regions of Turkey.

OBJECTIVE

To establish the anticonvulsant activity potential of G. olivieri.

MATERIALS AND METHODS

In this work, the ethanol extract of G. olivieri was tested in three doses (200, 750 and 1000 mg/kg) for anticonvulsant activity against seizures produced in mice by pentylenetetrazole (PTZ), picrotoxin (PIC) and maximal electroshock (MES). Neurotoxicity of the ethanol extract was also determined by the Rota rod test to evaluate the safety. Ethosuximide (150 mg/kg), diazepam (0.5 mg/kg) and carbamazepine (30 mg/kg) were used as reference drugs.

RESULTS

Intraperitonally, injection of the extract significantly prolonged the onset of seizures at doses of 200 and 750 mg/kg, but did not alter the incidence of PTZ-induced seizures. Onset of PIC-induced seizures was delayed by the injection of the extract (1000 mg/kg). Moreover, only 750 mg/kg of the extract protected 25% of the mice against PIC-induced seizures. On the other hand, G. olivieri extract (200, 750 and 1000 mg/kg) showed a significant protective effect against MES-induced seizures. In the Rota rod test, the ethanol extract (200 mg/kg, ip) induced disturbance in motor coordination.

CONCLUSION

The results indicate that G. olivieri has possessed anticonvulsant activity against MES-induced seizures in mice.

Decoctions of Bridelia micrantha and Croton macrostachyus may have anticonvulsant and sedative effects

Bridelia micrantha and Croton macrostachyus are medicinal plants used empirically in traditional medicine to treat epilepsy. In vivo mice model (maximal electroshock, strychnine, pentylenetetrazol, picrotoxin, isonicotinic hydrazide acid)-induced convulsions were used to evaluate the anticonvulsant activities of those plants. Diazepam-induced sleep was used for the evaluation of the sedative properties. B. micrantha protected 100, 80, 80, and 80% of mice against PIC, STR, PTZ and MES-induced seizures, respectively. C. macrostachyus at the doses 34 and 67 mg/kg protected 80, 80, 80 and 60% of mice from PIC, STR, PTZ and MES-induced seizures, respectively. B. micrantha and C. macrostachyus also delayed the onset to seizures in INH test. B. micrantha was more potent than C. macrostachyus in protecting mice against convulsions. The co-administration of the sub effective dose of the decoction of B. micrantha or C. macrostachyus with the sub effective dose of diazepam or clonazepam resulted in a synergistic effect. The decoctions of B. micrantha and C. macrostachyus also exerted sedative activity by increasing the total duration of sleep induced by diazepam and by reducing the latency time to sleep. The effect of the decoctions of B. micrantha and C. macrostachyus suggests the presence of anticonvulsant activities that might show efficacy against secondarily generalized tonic-clonic seizures and primary generalized seizures in humans.

UPLC-TOF-MS analysis of Galium spurium towards its neuroprotective and anticonvulsant activities

ETHNOPHARMACOLOGICAL RELEVANCE

Galium species have been reported to be used against epilepsy in traditional Turkish folk medicine.

AIM OF STUDY

The present work was undertaken to evaluate the in vivo anticonvulsant and in vitro neuroprotective effects of Galium spurium L. and to determine the major constituents by UPLC-TOF-MS.

MATERIALS AND METHODS

Anticonvulsant activity of the aerial parts of Galium spurium was investigated using pentylenetetrazole, picrotoxin, and maximal electroshock-induced seizure animal models. In order to evaluate the safety, neurotoxicity (Rota rod test) of the ethanol extract was also determined. In vitro neuroprotective effect of the ethanol extract of Galium spurium was assessed by acetylcholinesterase and butrylcholinesterase inhibitions. Ultra Performance Liquid Chromatography-Time of Flight Mass Spectrometer (UPLC-TOF-MS) was used to identify the major compounds in the extract.

RESULTS

In pentylenetetrazole-induced seizure, the ethanol extract at doses of 250 and 1000mg/kg prolonged the onset of seizures. Similarly, Galium spurium (250 and 500mg/kg) significantly delayed the onset of picrotoxin-induced seizures in mice and these doses also exhibited 12.5% and 17% protection, respectively, against picrotoxin-induced seizures. Furthermore, Galium spurium extract showed a significant protective effect against maximal electroshock-induced seizures at doses of 250 and 1000mg/kg (50% and 37.5%, respectively) and also all tested doses prolonged the onset of seizures. No motor co-ordination was observed with intraperitoneal injection of Galium spurium extract at doses of 500 and 1000mg/kg. The extract exhibited 16.2% inhibition against butrylcholinesterase at 200μg/mL concentration, whereas it did not inhibit acetylcholinesterase. Phytochemical analysis of the extract based on the MS data by UPLC-TOF-MS, ten major compounds (phenolic and triterpenic acids, flavonoids and iridoids) were determined.

CONCLUSIONS

The results indicate that Galium spurium may have anticonvulsant activity against picrotoxin and maximal electroshock-induced seizures in mice. Phenolic acids, flavonoids and iridoids might be responsible for anticonvulsant activity. The results offer possible beneficial effects by the plant's aerial parts and may suggest a realistic explanation for its traditonal usage in epilepsy.

Evaluation of possible antioxidant and anticonvulsant effects of the ethyl acetate fraction from Platonia insignis Mart. (Bacuri) on epilepsy models

The aim of present study was to examine the effects of the ethyl acetate fraction (EAF) from Platonia insignis on lipid peroxidation level, nitrite formation, and superoxide dismutase and catalase activities in rat striatum prior to pilocarpine-induced seizures as well as to explore its anticonvulsant activity in adult rats prior to pentylenetetrazole (PTZ)- and picrotoxin (PIC)-induced seizures. Wistar rats were treated with vehicle, atropine (25mg/kg), EAF (0.1, 1, and 10mg/kg), pilocarpine (400mg/kg, P400 group), PTZ (60 mg/kg, PTZ group), PIC (8 mg/kg, PIC group), atropine+P400, EAF+P400, EAF+PTZ, or EAF+PIC. Significant decreases in number of crossings and rearings were observed in the P400 group. The EAF 10+P400 group also had significant increases in these parameters. In addition, in rats treated with P400, there were significant increases in lipid peroxidation and nitrite levels; however, there were no alterations in SOD and catalase activities. In the EAF 10+P400 group, lipid peroxidation and nitrite levels significantly decreased and SOD and catalase activities significantly increased after pilocarpine-induced seizures. Additionally, effects of the EAF were evaluated in PTZ and PIC models. EAF did not increase the latency to development of convulsions induced with PTZ and PIC at the doses tested. Our findings strongly support the hypothesis that EAF does not have anticonvulsant activity in the different models of epilepsy studied. Our results indicate that in the in vivo model of pilocarpine-induced seizures, EAF has antioxidant activity, but not anticonvulsant properties at the doses tested.

Central Nervous System Effects of Iso-6-spectaline Isolated from Senna Spectabilis var. Excelsa (Schrad) in Mice

The central nervous system (CNS) depressant and anticonvulsant activities of iso-6-spectaline (SPEC) were investigated in animal models. The SPEC from Senna spectabilis var. excelsa (Schrad) (0.1, 0.5 and 1.0 mg/ kg) injected by oral route (p.o.) in mice caused a significant decrease in the motor activity up to 30 days after the administration and in the dose of 1.0 mg/kg significantly reduced the remaining time on the Rota-rod apparatus. Additionally, SPEC (0.1, 0.5 and 1.0 mg/kg, p.o.) was also capable of promoting increase of latency for development of convulsions induced by pentylenetetrazole. This SPEC was also capable of promoting an increase of latency for development of convulsions induced by picrotoxin at highest dose. In the same way, the anticonvulsant effect of SPEC was affected by pretreatment with flumazenil, a selective antagonist of the benzodiazepine site of the GABA_A receptor. These results suggest possible CNS depressant and anticonvulsant activities in mice that needs further investigation.

Anticonvulsant Activity of Argyreia speciosa in Mice

Argyreia speciosa commonly known as Vridha daraka in Sanskrit is one of the important plants used in indigenous system of medicine. The root is regarded as an alternative tonic and useful in the diseases of nervous system. To confirm the veracity of aforementioned claim, we have evaluated the anticonvulsant effect of the extract. In this investigation, the mice were pretreated with different doses of Argyreia speciosa extract (100, 200, 400 mg/kg) for 10 days and then, they were subjected to either pentylenetetrazole (80 mg/kg) or maximal electroshock seizures (50 mA, 0.2 s) treatment. The hydroalcoholic extract of Argyreia speciosa at the dose of 200 and 400 mg/kg significantly delayed the latency to the onset of first clonus as well as onset of death in unprotected mice and exhibited protection in 16.66% and 33.33% of pentylenetetrazole treated mice respectively. Whereas in case of maximal electroshock-seizures, the dose of 200 and 400 mg/kg significantly reduced the duration of hind limb extension and both the doses were statistically found to be equipotent. The reference standards, clonazepam (0.1 mg/kg) and phenytoin (20 mg/kg) provided complete protection. Thus, present study revealed anticonvulsant effect of Argyreia speciosa against pentylenetetrazole- and maximal electroshock-induced convulsions in mice.

Evaluation of the sedative and anticonvulsant properties of three Cameroonian plants

Millettia thonningii, Ocinum sanctum and Securitaca longepedunculaca are used in traditional medicine in Cameroon to treat epilepsy, insomnia and headaches. Animal models of epilepsy (maximal electroshock (MES), n-methyl-d-aspartate (NMDA), pentylenetetrazol (PTZ), isonicotinic hydrazide acid (INH), picrotoxine (PIC) and strychnine (STR)-induced convulsions or turning behavior were used to evaluate anticonvulsant activity while diazepam-induced sleep test was used to evaluate sedative activity of the plants. Four doses of extracts were used for each plant (100, 200, 500 and 1000 mg/kg). At a dose of 1000 mg/kg, Millettia thonningii protected 60 and 90% of mice against MES and PTZ-induced convulsions, respectively. At the same dose, Millettia thonningii also protected 80% of mice against NMDA-induced turning behavior. At a dose of 1000 mg/kg, Ocinum sanctum provided complete protection against MES, PIC and STR- induced convulsions and 83.3% of protection in PTZ test. Securitaca longepedunculata completely protected (100%) mice in PIC test at a dose of 200 mg/kg, in MES test at a dose of 500 mg/kg and in PTZ test at a dose of 1000 mg/kg. 66.7% of mice were protected against STR-induced convulsions. All the three plants showed also sedative properties for they increased significantly and in a dose dependent manner the total sleep time induced by diazepam. The total sleep time of the control groups was multiplied by a factor of 3 at least by each extract. The presence of sedative and anticonvulsant activity in the three plants could explain their use in traditional medicine in the treatment of epilepsy and insomnia in Cameroon.

Anticonvulsant Activity of the Linalool Enantiomers and Racemate: Investigation of Chiral Influence

The anticonvulsant activity of the racemate and enantiomers of linalool have been evaluated. Pretreatment of the mice with ( S)-(+)-, ( R)-(-)- and rac-linalool increased the latency of convulsions significantly in the PTZ model. Only rac-linalool had an effect at the dose of 200 mg/kg. The enantiomers and their racemic mixture were effective in inhibiting the convulsant effect of PTZ at the dose of 300 mg/kg. The linalools presented pharmacological activity close to that of diazepam. In the PIC seizure model, ( R)-(-)-linalool and rac-linalool presented activity at the dose of 200 mg/kg, but the rac-linalool was more potent than ( R)-(-)-linalool; ( S)-(+)-linalool had no effect at this dose. On the other hand, at the dose of 300 mg/kg this enantiomer was effective, but less potent than ( R)-(-)-linalool and rac-linalool. In the MES model, linalools decreased the convulsion time of the mice in the doses of 200 and 300 mg/kg. rac-Linalool presented maximum effect at 300 mg/kg. Surprisingly, it increased significantly the convulsion time at a dose of 100 mg/kg. Using the parameter of tonic hind convulsions, only ( R)-(-)-linalool produced protection from tonic extension at the dose of 200 mg/kg. When the (+)- and (-)-enantiomers, and rac-linalool were administered at the dose of 300 mg/kg they were also effective in preventing tonic convulsions induced by transcorneal electroshock in the animals. The (+)- and (-)-forms were equipotent and the rac-linalool was more effective than phenytoin. We have demonstrated that the two enantiomers have similar qualitative anticonvulsant activity, but show different potencies.

Anticonvulsant activity of Benkara malabarica (Linn.) root extract: In vitro and in vivo investigation

AIM OF THE STUDY

To systematically investigate the anticonvulsant activity of methanol extract of Benkara malabarica roots and to provide a biochemical basis elucidating its mode of action.

METHODS

The median lethal dose (LD(50)) of Benkara malabarica extract was determined. The anticonvulsant activity of the extract was assessed in strychnine-induced and isoniazide-induced convulsion models; phenytoin (20mg/kg) and diazepam (1mg/kg) were used as standards, respectively. Percentage protection provided by the drug was accounted as decrease in the number of convulsions within 8h of observation. Mechanism of action was studied by performing GABA transaminase (GABA-T) assay, isolated from rat brain. Active constituent was isolated and characterized from the plant extract.

RESULTS

The median lethal dose (LD50) of Benkara malabarica was found to be more than 500 mg/kg. It demonstrated 30% and 35% protection against strychnine-induced convulsions and 60% and 80% protection against isoniazide-induced convulsions, at doses of 25mg/kg and 50mg/kg, respectively. Enzyme assay results revealed that Benkara malabarica extract possesses GABA-T inhibitory activity (IC50=0.721 mg/ml). Scopoletin which was identified as the major constituent of the extract was found to be an inhibitor of GABA-T (IC50=10.57 microM).

CONCLUSIONS

The anticonvulsant activity of the plant extract is predominantly GABA mediated and may be due to the action of scopoletin alone or is a result of synergy of different compounds in the extract in which scopoletin is the major constituent.