Review on phytotherapy in epilepsy

Natural product-derived therapies for treating drug-resistant epilepsies: From ethnopharmacology to evidence-based medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Epilepsy is one of the most prevalent neurological human diseases, affecting 1% of the population in all age groups. Despite the availability of over 25 anti-seizure medications (ASMs), which are approved in most industrialized countries, approximately 30% of epilepsy patients still experience seizures that are resistant to these drugs. Since ASMs target only limited number of neurochemical mechanisms, drug-resistant epilepsy (DRE) is not only an unmet medical need, but also a formidable challenge in drug discovery.

AIM

In this review, we examine recently approved epilepsy drugs based on natural product (NP) such as cannabidiol (CBD) and rapamycin, as well as NP-based epilepsy drug candidates still in clinical development, such as huperzine A. We also critically evaluate the therapeutic potential of botanical drugs as polytherapy or adjunct therapy specifically for DRE.

METHODS

Articles related to ethnopharmacological anti-epileptic medicines and NPs in treating all forms of epilepsy were collected from PubMed and Scopus using keywords related to epilepsy, DRE, herbal medicines, and NPs. The database clinicaltrials.gov was used to find ongoing, terminated and planned clinical trials using herbal medicines or NPs in epilepsy treatment.

RESULTS

A comprehensive review on anti-epileptic herbal drugs and natural products from the ethnomedical literature is provided. We discuss the ethnomedical context of recently approved drugs and drug candidates derived from NPs, including CBD, rapamycin, and huperzine A. Recently published studies on natural products with preclinical efficacy in animal models of DRE are summarized. Moreover, we highlight that natural products capable of pharmacologically activating the vagus nerve (VN), such as CBD, may be therapeutically useful to treat DRE.

CONCLUSIONS

The review highlights that herbal drugs utilized in traditional medicine offer a valuable source of potential anti-epileptic drug candidates with novel mechanisms of action, and with clinical promise for the treatment of drug-resistant epilepsy (DRE). Moreover, recently developed NP-based anti-seizure medications (ASMs) indicate the translational potential of metabolites of plant, microbial, fungal and animal origin.

In vitro and in vivo anti-seizure activity of hydromethanolic extract and fractions of Pterolobium stellatum

ETHNOPHARMACOLOGICAL RELEVANCE

In Ethiopia, the whole plant juice of Pterolobium stellatum is used to treat seizures and epilepsy.

AIM OF THE STUDY

To investigate the antiseizure activity of hydromethanolic crude extract and fractions collected from leaves of P. stellatum using both in vitro, and in vivo seizure models in mice.

MATERIALS AND METHODS

Fresh leaves of P. stellatum were collected from Awash Melka, Addis Ababa, Ethiopia. An 80% crude methanol extract was further fractionated to produce petroleum ether, chloroform, butanol, and aqueous fractions. Anti-seizure activity of the crude extract and fractions (petroleum ether, chloroform, butanol, and water) were assessed at a concentration of 0.7 mg/ml using the in vitro 0 Mg²⁺ model of seizures in mouse brain slices prepared from 14- to 21-day-old C57BL/6 mice. The maximal electroshock seizure (MES) model and the pentylenetetrazol (PTZ) seizure model for seizures were performed on male BALB/c mice using 400 mg/kg and 800 mg/kg of crude 80% methanol extract, as well as the four fractions described above. Diazepam and phenytoin were used as positive controls for PTZ and MES test respectively.

RESULTS

Addition of 0.7 mg/ml of crude 80% methanol extract of P. stellatum prevented the onset of SLEs in most brain slices in the 0 Mg²⁺in vitro model of seizures, with similar efficacy to diazepam (3 μM). The same extract at 400 and 800 mg/kg was efficacious in reducing the hindlimb extension time in the MES model and delaying the onset of myoclonic convulsions in the PTZ model, although not to the same extent as phenytoin (10 mg/kg) or diazepam (5 mg/kg). The chloroform and water fractions of the crude extract also showed significant anti-seizure activity across all three models whilst the non-polar petroleum ether and butanol fractions did not. The UPLC-MS analysis indicated the presence of gallic acid, ellagic acid, kaempferol, myricitrin, isoquercitrin and quercitirin in the crude extract. Gallic acid and ellagic acid were observed in chloroform fraction and in the water fraction ellagic acid, kaempferol, myricitrin and isoquercitrin were detected.

CONCLUSION

The crude hydromethanolic extract of P. stellatum has significant anti-seizure activity. The chloroform and aqueous fractions have antiseizure activity. The extracts have previously identified compounds with anticonvulsant activity which indicates the antiseizure potential of the plant.

Extract of Euterpe oleracea Martius Stone Presents Anticonvulsive Activity via the GABAA Receptor

Epilepsy is one of the most common neurological diseases globally, resulting from a disorder in brain activity. This condition can be triggered by birth trauma, traumatic brain injury (TBI), infections of the brain and stroke. More than 70 million people suffer seizures caused by neurological abnormalities. Approximately 80% of all epileptic patients reside in low-income conditions or in developing countries, and over 75% of patients do not receive proper treatment. Our previous study found an anticonvulsant property of an extract of Euterpe oleracea stone (EEOS) that caused myorelaxation, sedation, and cardiac and respiratory depression after intraperitoneal administration. The present study investigated through electroencephalographic (EEG) profiling the anticonvulsant protective properties of EEOS in induced convulsing rats. Male Wistar rats were treated with EEOS (300 mg/kg), diazepam (DZP) (5 mg/kg), pentylenetetrazol (PTZ) (60 mg/kg) and flumazenil (FMZ) (0.1 mg/kg) by intraperitoneal (i.p.). Electrodes implanted on the dura mater provided EEG data in which EEOS suppressed seizure deflagration caused by PTZ. In addition, EEOS presented no significant difference in comparison to DZP, which has the same mechanism of action. After FMZ injection, a GABAA receptor antagonist blocked the anticonvulsive effect in both the DZP and EEOS groups, suggesting that EEOS exerts it action on the GABAA receptor at the benzodiazepine (BDZ) subunit.

Pharmacological screening of Eryngium foetidum Linn – A Review

Eryngium foetidum L. (Family Apiaceae) is a biennial herb, and it is used as a culinary herb and spice across the different countries of the world, including Sri Lanka, India, Bangladesh, Malaysia, Singapore, etc. due to its high aroma quality. Also, it is used to treat several ailments, such as respiratory diseases, gastrointestinal ailments, and skin diseases among different indigenous populations for its medicinal properties. Based on ethnomedical evidence, many studies have been conducted to identify the phytoconstituents, underlying mechanisms, and related pharmacological effects of different parts of this plant. This study reviewed the current state of findings related to the Pharmacological activities of E. foetidum. Based on this review, this plant is widely used for ethnomedical and culinary purposes. Pharmacological screening of the plant revealed that it had different activities such as anti-inflammatory, antioxidant, antimicrobial, anthelminthic, anticonvulsant, anticancer, antidiabetic, antimalarial, larvicidal, and hepatoprotective activities. This review further promised that potential new chemical entities could be elicited from the phytoconstituents of E. foetidum.

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.

Screening Study for Anticonvulsive Activity of Lipophilic Fractions from Empetrum nigrum L

Introduction: The plants of genus Empetrum, which are used in the traditional medicine to cure seizures and neurodegenerative diseases, can be considered as potent antiepileptic drugs. This paper focuses on a comparative analysis of an anticonvulsive activity of lipophilic fractions from Empetrum nigrum L.

Materials and methods: The experiments were conducted using mature outbred CD-1 male mice. The lipophilic fractions from aerial parts of Empetrum nigrum L. were administered through a catheter into the stomach at a dose of 150 mg/kg for 5 days. The anticonvulsive effects were studied using the acute seizure tests: strychnine-, pentylenetetrazole – and maximal electroshock (MES) induced tests. Carbamazepine was used as a positive control drug at a dose of 100 mg/kg.

Results and discussion: The acetone-soluble fraction (ASF) of the chloroform extract from Empetrum nigrum L. showed a pronounced anticonvulsive effect on seizures induced by strychnine (1.5 mg/kg) and pentylenetetrazole (150 mg/kg). In comparison to the control group, the time from seizures to death increased by 1.5 for the strychnine-induced seizures, and 1.9 times in case of pentylenetetrazole model. The survival rate of the animals was 22.2% and 20%, correspondingly. The survival rate in the MES test was 77.8%. Overall, ASF demonstrates a remarkable anticonvulsive activity in all the tests, especially in the MES test.

Conclusion: Our study for the first time shows a potent antiepileptic effect of ASF from Empetrum nigrum L., containing triterpene compounds and chalcones. The future studies will be focused on investigating the exact mechanisms of anticonvulsive and neuroprotective effects of ASF.

Neuro-pharmacological evaluation of anticonvulsant and neuroprotective activity of Cocculus laurifolius leaves in wistar rats

The aim of the study was to evaluate the anticonvulsant and neuroprotective activity of Cocculus laurifolius D.C leaves in albino wistar rats against strychnine induced convulsions. Initially the extract was investigated for acute oral toxicity testing in order to examine any signs of toxicity and mortality. For anticonvulsant activity, the ethanolic extract was evaluated at doses 200 and 400 mg/kg, p.o. against strychnine induced convulsions model, at 1, 7, 15 and 30th day of treatment. Meanwhile, the neuroprotective effect of the extract was investigated via histopathological assessment. Cocculus laurifolius (200 and 400 mg/kg, p.o.) exhibited anticonvulsant activity as indicated by significant delay in the onset of convulsions and time to death after strychnine induced convulsions. Similarly, significant reduction in the duration of convulsions and percentage of mortality was observed by ethanolic extract (200 and 400 mg/kg p.o.) at 1, 7, 15 and 30th day of test sessions. Furthermore, Cocculus laurifolius leaves (200 and 400 mg/kg p.o.) also exhibited neuroprotective effect with considerable preserved neuronal structures and significant decrease in neuronal apoptosis, in comparison with control. The results obtained from the present study indicate that ethanolic extract of Cocculus laurifolius leaves possess potential anticonvulsant and neuroprotective effect against strychnine induced convulsions. Therefore, it can be concluded that Cocculus laurifolius leaves may be a valuable in management of epilepsy, however further studies are required on large number of animals to confirm these findings.

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.

Myristica Fragrans Houtt Extract Attenuates Neuronal Loss and Glial Activation in Pentylenetetrazol-Induced Kindling Model

Inflammatory reactions are closely associated with the development and progression of epilepsy. It has been shown that inhibition of pro-inflammatory cytokines, which are released from activated astrocytes and microglia, are considered to be an effective therapeutic approach for the treatment of epileptic disorders. Regarding the anti-inflammatory effects of nutmeg (Myristica fragrans Houtt), the present study was designed to investigate whether the nutmeg ethanolic extract could exert anticonvulsant and inhibitory effects on glial activation in pentylenetetrazol (PTZ)-induced mice model of kindling. Ethanolic extract of nutmeg was administrated intraperitoneally (i.p.) 1 hour before PTZ injection or one week before PTZ as a separate group, to become fully-kindled. The chemical components of nutmeg extract were analyzed by gas chromatography mass spectrometry (GC-MS). Immunostaining against neuronal and glial markers was performed on hippocampus sections. GC-MS data indicated that the main components of nutmeg extract are myristic acid (39.93%), elemicin (22.16%) and myristicin (11.17%). Behavioral studies showed that pre-treatment of nutmeg extract effectively reduced seizures behavior, decreased cell death, and ameliorated glial activation that is followed by PTZ administration. In conclusion, nutmeg extract might be regarded as a useful supplementary agent in epilepsy treatment through its attenuation of neuronal loss and glial activation.

Why Are the Majority of Active Compounds in the CNS Domain Natural Products? A Critical Analysis

Small-molecule natural products (NPs) have a long and successful track record of providing first-in-class drugs and pharmacophore (scaffolds) in all therapeutic areas, serving as a bridge between modern and traditional medicine. This trajectory has been remarkably successful in three key areas of modern therapeutics: cancers, infections, and CNS diseases. Beginning with the discovery of morphine 200 years ago, natural products have remained the primary source of new drugs/scaffolds for CNS diseases. In this perspective, we address the question: why are the majority of active compounds in the CNS domain natural products? Our analysis indicates that ∼84% approved drugs for CNS diseases are NPs or NP-inspired, and interestingly, 20 natural products provided more than 400 clinically approved CNS drugs. We have discussed unique physicochemical properties of NPs and NP-inspired vis-à-vis synthetic drugs, isoform selectivity, and evolutionary relationship, providing a rationale for increasing focus on natural product driven discovery for next-generation drugs for neurodegenerative diseases.

Evidence for the involvement of the GABA-ergic pathway in the anticonvulsant activity of the roots bark aqueous extract of Anthocleista djalonensis A. Chev. (Loganiaceae)

BACKGROUND

The root bark of Anthocleista djalonensis A. Chev. (Loganiaceae) is widely used in traditional medicine in Northern Cameroon to treat epilepsy and related conditions, such as migraine, insomnia, dementia, anxiety, and mood disorders.

METHODS

To investigate the anticonvulsant effects and the possible mechanisms of this plant, an aqueous extract of Anthocleista djalonensis (AEAD) was evaluated by using animal models of bicuculline-, picrotoxin-, pilocarpine-, and pentylenetetrazole-induced convulsions. Their effects on brain γ-aminobutyric acid (GABA) concentration and GABA-T activity were also determined.

RESULTS

This extract significantly protected mice against bicuculline-induced motor seizures. It provided 80% protection against picrotoxin-induced tonic-clonic seizures, and strongly antagonized convulsions induced by pilocarpine. AEAD also protected 100% of mice against pentylenetetrazole-induced seizures. Flumazenil, a central benzodiazepine receptor antagonist and FG7142, a partial inverse agonist in the benzodiazepine site of the GABAA receptor complex, were found to have an inhibitory effect on the anticonvulsant action of AEAD in pentylenetetrazole test. Finally, the brain GABA concentration was significantly increased and GABA-T activity was inhibited by AEAD.

CONCLUSIONS

The effects of Anthocleista djalonensis suggested the presence of anticonvulsant properties that might involve an action on benzodiazepine and/or GABA sites in the GABAA receptor complex or by modulating GABA concentration in the central nervous system (CNS).

The Effects of 4-Hydroxybenzoic Acid Identified from Bamboo (Dendrocalamus asper) Shoots on Kv1.4 Channel

Background

Bamboo shoot has been used as a treatment for epilepsy in traditional Chinese medicine for generations to treat neuronal disorders such as convulsive, dizziness and headaches. 4-hydroxybenzoic acid (4-hba) is a non-flavonoid phenol found abundantly in Dendrocalamus asper shoots (bamboo), fruits (strawberries and apples) and flowers. Kv1.4 is a rapidly inactivating Shaker-related member of the voltage-gated potassium channels with two inactivation mechanisms; the fast N-type and slow C-type. It plays vital roles in repolarisation, hyperpolarisation and signaling the restoration of resting membrane potential through the regulation of the movement of K⁺ across the cellular membrane.

Methods

Chemical compounds from Dendrocalamus asper bamboo shoots were purified and identified as major palmitic acids mixed with other minor fatty acids, palmitic acid, 4-hydroxybenzaldehyde, lauric acid, 4-hydroxybenzoic acid and cholest-4-ene-3-one. The response of synthetic 4-hydroxybenzoic acid was tested on Kv1.4 potassium channel which was injected into viable oocytes that was extracted from Xenopus laevis. The current were detected by the two-microelectrode voltage clamp, holding potential starting from -80 mV with 20 mV step-up until +80 mV. Readings of treatments with 0.1% DMSO, 4-hba concentrations and K channel blockers were taken at +60 mV. The ratio of tail/peak amplitude is the index of the activity of the Kv1.4 channels with n ≥ 6 (number of oocytes tested). The decreases of the ratios of five different concentrations (1 μM, 10 μM, 100 μM, 1 mM and 2.5 mM) were compared with 0.1% DMSO as the control.

Results

All concentration showed statistically significant results with P < 0.05 except for 100 μM. The normalised current of the 4-hba concentrations were compared with potassium channel blockers (TEA and 4-AP) and all groups showed statistically significant results. This study also showed that time taken for each concentration to affect Kv1.4 does not play any significant roles.

Conclusion

4-hydroxybenzoic acid was found to be able to enhance the inactivation of Kv1.4 by lowering the membrane potential so that the abnormal neuronal firing can be inhibited. With IC50 slightly higher than 10 μM, increasing concentrations (100 μM, 1 mM and 2.5 mM) had shown to exhibit toxicity effects. The best concentration from this study is 10 μM with Hill slope of 0.1799.

Preliminary Screening of a Classical Ayurvedic Formulation for Anticonvulsant Activity

BACKGROUND

Epilepsy is a serious and complex central nervous system disorder associated with recurrent episodes of convulsive seizures due to the imbalance between excitatory (glutamatergic) and inhibitory (GABAergic) neurotransmitters level in the brain. The available treatments are neither competent to control the seizures nor prevent progress of disease. Since ages, Herbal medicines have remained important sources of medicines in many parts of world which is evidenced through their uses in traditional systems of medicine i.e. Ayurveda, Siddha, Unani, Homeopathy and Chinese etc.

AIM

A polyherbal formulation (containing Terminalia chebula Retz., Asparagus racemosus Willd., Embelia ribes Burm. F, Acorus calamus L., Tinospora cordifolia (Willd.) Miers, Convolvulus pluricaulis Choisy, Saussurea lappa C.B.Clarke, Achyranthes aspera L.) is mentioned in Ayurvedic classics Bhaiṣajya Ratnāvali. The aim of the study was to evaluate the anticonvulsant activity of the formulation in Maximum electroshock and Pentylenetetrazole induced convulsions in rats.

MATERIALS AND METHODS

In the present study, a polyherbal formulation was developed as directed by classical text and evaluated for the anticonvulsant activity using Maximal Electroshock Shock (MES) and Pentylenetetrazole (PTZ) induced convulsions in rats. Statistical comparison was done by one way ANOVA followed by the Tukey's multiple comparison test.

RESULTS

The obtained results showed that the PHF had a protective role on epilepsy. Treatment with PHF significantly improves antioxidant enzymes activities of superoxide dismutase (SOD) and glutathione (GSH) levels significantly as compared to controls. PHF also significantly decreased malonaldialdehyde (MDA) levels in the brain. Moreover, it also attenuated the PTZ-induced increase in the activity of GABA-T in the rat brain.

CONCLUSION

These findings suggest that PHF might have possible efficacy in the treatment of epilepsy.

A pharmacological basis of herbal medicines for epilepsy

Epilepsy is the most common chronic neurological disease, affecting about 1% of the world's population during their lifetime. Most people with epilepsy can attain a seizure-free life upon treatment with antiepileptic drugs (AEDs). Unfortunately, seizures in up to 30% do not respond to treatment. It is estimated that 90% of people with epilepsy live in developing countries, and most of them receive no drug treatment for the disease. This treatment gap has motivated investigations into the effects of plants that have been used by traditional healers all over the world to treat seizures. Extracts of hundreds of plants have been shown to exhibit anticonvulsant activity in phenotypic screens performed in experimental animals. Some of those extracts appear to exhibit anticonvulsant efficacy similar to that of synthetic AEDs. Dozens of plant-derived chemical compounds have similarly been shown to act as anticonvulsants in various in vivo and in vitro assays. To a significant degree, anticonvulsant effects of plant extracts can be attributed to widely distributed flavonoids, (furano)coumarins, phenylpropanoids, and terpenoids. Flavonoids and coumarins have been shown to interact with the benzodiazepine site of the GABAA receptor and various voltage-gated ion channels, which are targets of synthetic AEDs. Modulation of the activity of ligand-gated and voltage-gated ion channels provides an explanatory basis of the anticonvulsant effects of plant secondary metabolites. Many complex extracts and single plant-derived compounds exhibit antiinflammatory, neuroprotective, and cognition-enhancing activities that may be beneficial in the treatment of epilepsy. Thus, botanicals provide a base for target-oriented antiepileptic drug discovery and development. In the future, preclinical work should focus on the characterization of the effects of plant extracts and plant-derived compounds on well-defined targets rather than on phenotypic screening using in vivo animal models of acute seizures. At the same time, available data provide ample justification for clinical studies with selected standardized botanical extracts and plant-derived compounds. This article is part of a Special Issue entitled "Botanicals for Epilepsy".

In silico inhibition of GABARAP activity using antiepileptic medicinal derived compounds

Epilepsy is a neurological disorder affecting more than 50 million people worldwide. It can be controlled by antiepileptic drugs (AEDs) but more than 30% patients are still resistant to AEDs. To overcome this problem, researchers are trying to develop novel approaches to treat epilepsy including the use of herbal medicines. The γ-amino butyric acid type-A receptor associated protein (GABARAP) is ubiquitin-like modifier implicated in the intracellular trafficking of GABAAR. An in silico mutation was created at 116 amino acid position G116A, and an in silico study was carried out to identify the potential binding inhibitors (with antiepileptic properties) against the active sites of GABARAP. Five different plant derived compounds namely (a) Aconitine (b) Berberine (c) Montanine (d) Raubasine (e) Safranal were selected, and their quantitative structure-activity relationships (QSAR) have been conducted to search the inhibitory activity of the selected compounds. The results have shown maximum number of hydrogen bond (H-bond) interactions of Raubasine with highest interaction energy among all of the five compounds. So, Raubasine could be the best fit ligand of GABARAP but in vitro, and in vivo studies are necessary for further confirmation.

Epilepsy in the Renaissance: a survey of remedies from 16th and 17th century German herbals

ETHNOPHARMACOLOGICAL RELEVANCE

Before modern anticonvulsive drugs were developed people in central Europe used herbal remedies to treat epilepsy. Hundreds of different plants for this indication can be found in German herbals of the 16th and 17th centuries. Here we compile these plants and discuss their use from a pharmacological perspective.

MATERIALS AND METHODS

Nine of the most important European herbals of the 16th and 17th century including Bock (1577), Fuchs (1543), Mattioli (1590), Lonicerus (1660, 1770), Brunfels (1532), Zwinger (1696), and Tabernaemontanus (1591, 1678) were searched for terms related to epilepsy, and plants and recipes described for its treatment were documented. We then searched scientific literature for pharmacological evidence of their effectiveness. Additionally the overlapping of these remedies with those in De Materia Medica by the Greek physician Dioscorides was studied.

RESULTS

Two hundred twenty one plants were identified in the herbals to be used in the context of epilepsy. In vitro and/or in vivo pharmacological data somehow related to the indication epilepsy was found for less than 5% of these plants. Less than 7% of epilepsy remedies are in common with De Materia Medica.

CONCLUSIONS

Numerous plants were used to treat epilepsy in the 16th and 17th centuries. However, few of these plants have been investigated with respect to pharmacological activity on epilepsy related targets.

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.

Anticonvulsant effect of Marsilea quadrifolia Linn. on pentylenetetrazole induced seizure: a behavioral and EEG study in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Marsilea quadrifolia Linn (MQ) extract has been used traditionally as sedative and antiepileptic drug in India.

AIM OF THIS STUDY

To investigate the anticonvulsive potential of MQ extracts by using behavior and electroencephalographic (EEG) analysis on pentylenetetrazole (PTZ) induced seizure model in rats.

MATERIALS AND METHODS

For anticonvulsant effect, 60minutes after administration of MQ, behavior and EEG were analyzed during PTZ (60mg/kg) induced seizures. Changes of EEG power, latency of onset of seizure, seizure severity score, and duration of epileptic seizure were determined.

RESULTS

Both the water and ethanol extract of MQ increased the latency of seizure but also decreased duration of epileptic seizure and seizure severity score. This reduction of seizure severity was also observed in EEG recording and EEG power analysis. The effectiveness of MQ ethanol extract is better than MQ water extract.

CONCLUSION

Both water and ethanol extract of MQ were effective in reducing the severity of behavioral and EEG seizures induced by PTZ in rats. This study justifies the traditional use of this plant in epilepsy.

Anticonvulsant activity of bisabolene sesquiterpenoids of Curcuma longa in zebrafish and mouse seizure models

Turmeric, obtained from the rhizomes of Curcuma longa, is used in South Asia as a traditional medicine for the treatment of epilepsy. To date, in vivo studies on the anticonvulsant activity of turmeric have focused on its principal curcuminoid, curcumin. However, poor absorption and rapid metabolism have limited the therapeutic application of curcumin in humans. To explore the therapeutic potential of turmeric for epilepsy further, we analyzed its anticonvulsant activity in a larval zebrafish seizure assay. Initial experiments revealed that the anticonvulsant activity of turmeric in zebrafish larvae cannot be explained solely by the effects of curcumin. Zebrafish bioassay-guided fractionation of turmeric identified bisabolene sesquiterpenoids as additional anticonvulsants that inhibit PTZ-induced seizures in both zebrafish and mice. Here, we present the first report of the anticonvulsant properties of bisabolene sesquiterpenoids and provide evidence which warrants further investigation toward the mechanistic understanding of their neuromodulatory activity.

Eryngium foetidum L.: a review

Eryngium foetidum L. is a biennial herb which is used extensively as a medicinal plant in most tropical regions. It is of increasing importance as a spice plant cultivated in India, Vietnam, Australia and elsewhere with well documented procedures for maximum yield. It also possesses a wide range of ethnomedicinal uses including treatment for burns, earache, fevers, hypertension, constipation, fits, asthma, stomach ache, worms, infertility complications, snake bites, diarrhea and malaria. Chemical evaluation of the leaves indicated the presence of flavonoids, tannins, a saponin and several triterpenoids; but no alkaloids were reported. A significant constituent of the essential oil of the plant is E-2-dodecenal ("eryngial"), with isomers of trimethylbenzaldehyde being present in lesser proportions. Variability in the composition of essential oil was clearly dependent on the geographic location of the growing plant. Pharmacological studies of the aerial plant parts have demonstrated anthelmintic activity due to eryngial, anti-inflammatory action due to the phytosterol fractions, anti-convulsant activity in the respective models, and selective antibacterial activity against Salmonella species and the Erwinia genus of bacteria. A fraction of the essential oil rich in eryngial is the subject of a US patent application for its effectiveness against parasitic trypanosomes, nematodes, fungi and bacteria in humans and other mammals. These findings suggest the need for further research of this herb and its products.

Neurobehavioral and toxicological activities of two potentially CNS-acting medicinal plants of Piper genus

Plants from the genus Piper are economically useful and some species have been indicated because of their medicinal properties in the central nervous system. However, few studies about toxicity and neurobehavioral effects have been conducted. In this study, two Piper species, P. amalago and P. mikanianum were investigated in rats to determine acute toxicity and to evaluate the ansiogenic/ansiolytic properties in the elevated plus-maze and the effects on locomotion and exploration in an open field. Additionally, genotoxic activities were evaluated, using the comet assay in several tissues and the micronucleus assay in bone marrow. The phytochemical analysis of both Piper species leaves suggests the presence of amide, essential oils, flavonoids and phenolic compounds. The LD(50) of P. amalago and P. mikanianum were estimated as 2,545 and 1,661 mg/kg, respectively. The behavioral and genotoxic parameters were determined after an intraperitoneal administration of P. amalago (250 or 420 mg/kg) or P. mikanianum (160 or 270 mg/kg). Both plants decreased the number of entries and time spent in the open arms in the plus-maze test, indicating an anxiogenic effect. Only P. mikanianum affected locomotion and exploration in the open field behavior test. No genotoxic or mutagenic effect was observed. Our results suggest that these Piper species act on the central nervous system, without induce genetic toxicity.

Comparative anticonvulsant activities of the essential oils (EOs) from Cymbopogon winterianus Jowitt and Cymbopogon citratus (DC) Stapf. in mice

The fresh leaves of Cymbopogon citratus are a good source of an essential oil (EO) rich in citral, and its tea is largely used in the Brazilian folk medicine as a sedative. A similar source of EO is Cymbopogon winterianus, rich in citronellal. The literature presents more studies on the EO of C. citratus and their isolated bioactive components, but only a few are found on the EO of C. winterianus. The objective of the present study was then to study, in a comparative way, the effects of both EOs on three models of convulsions (pentylenetetrazol, pilocarpine, and strychnine) and on the barbiturate-induced sleeping time on male Swiss mice. The animals (20-30 g) were acutely treated with 50, 100, and 200 mg kg(-1), intraperitoneally, of each EO, and 30 min later, the test was initiated. The observed parameters were: latency to the first convulsion and latency to death in seconds. Furthermore, the in vitro effects of the EOs were also studied on myeloperoxidase (MPO; a biomarker for inflammation) and lactate dehydrogenase (LDH; an index of cytotoxicity) releases from human neutrophils. The EOs radical-scavenging activities were also evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The results showed that both EOs were more active on the pentylenetetrazol-induced convulsion model, and C. citratus was even more efficient in increasing latency to the first convulsion and latency to death. Both parameters were potentiated in the presence of a lower dose of diazepam (reference drug) when associated to a lower dose of each EO (25 mg kg(-1)). Besides, their anticonvulsant effects were blocked by flumazenil, a known benzodiazepine antagonist. This effect was somewhat lower on the pilocarpine-induced convulsion, and better effects were seen only with the EOs' higher doses (200 mg kg(-1)). A similar result was observed on the strychnine-induced convulsion model. Both EOs potentiated the barbiturate-induced sleeping time. However, C. citratus was more efficient. Interestingly, both EOs completely blocked the MPO release from human neutrophils and showed no cytotoxic effect on the LDH release from human neutrophils. On the other hand, only a very low or no effect on the DPPH assay was observed with C. winterianus and C. citratus, respectively, indicating that the radical scavenging activity did not play a role on the EOs' effects. We conclude that the mechanism of action of the anticonvulsant effect of the EOs studied is, at least in part, dependent upon the GABAergic neurotransmission. In addition, their effects on inflammatory biomarkers can also contribute to their central nervous system activity.

Anticonvulsive effects of intracerebroventricular administration of rutin in rats

Various synthetic derivatives of natural flavonoids are known to have neuroactive properties. The aim of the present study was to investigate the anticonvulsant effects of rutin (3, 3', 4', 5, 7-pentahydrohyflavone-3-rhamnoglucoside), a flavonoid which is an important dietary constituent of food and plant-based beverages. To this end, we assessed the anticonvulsant effects of rutin in rats treated with pentylenetetrazole (PTZ) (90 mg/kg, i.p.) and sought to clarify this mechanism. Intracerebroventricular (i.c.v.) injection of rutin dose-dependently affected minimal clonic seizures (MCS) and generalized tonic-clonic seizures (GTCS) induced by PTZ, through increments in seizure onset. Additionally, pretreatment with flumazenil (5 nM, i.c.v.) abolished the anticonvulsant effects of rutin during the onset of both seizures. These results indicate that rutin has anticonvulsant effects in the brain, possibly through positive allosteric modulation of the GABA(A) receptor complex via interaction at the benzodiazepine site.

Anticonvulsant effects of aerial parts of Passiflora incarnata extract in mice: involvement of benzodiazepine and opioid receptors

Background

Passion flower (Passiflora incarnata) is used in traditional medicine of Europe and South America to treat anxiety, insomnia and seizure. Recently, it has shown antianxiety and sedative effects in human.

Methods

In this study, anticonvulsant effects of hydro- alcoholic extract of Passiflora, Pasipay, were examined by using pentylentetrazole model (PTZ) on mice. Pasipay, diazepam, and normal saline were injected intraperitoneally at the doses 0.4–0.05 mg/kg, 0.5–1 mg/kg and 10 ml/kg respectively 30 minutes before PTZ (90 mg/kg, i.p). The time taken before the onset of clonic convulsions, the duration of colonic convulsions, and the percentage of seizure and mortality protection were recorded. For investigating the mechanism of Pasipay, flumazenil (2 mg/kg, i.p) and naloxone (5 mg/kg, i.p) were also injected 5 minutes before Pasipay.

Results

An ED₅₀ value of Pasipay in the PTZ model was 0.23 mg/kg (%95 CL: 0.156, 0.342). Pasipay at the dose of 0.4 mg/kg prolonged the onset time of seizure and decreased the duration of seizures compared to saline group (p < 0.001). At the dose of 0.4 mg/kg, seizure and mortality protection percent were 100%. Flumazenil and naloxone could suppress anticonvulsant effects of Pasipay.

Conclusion

It seems that Pasipay could be useful for treatment absence seizure and these effects may be related to effect of it on GABAergic and opioid systems. More studies are needed in order to investigate its exact mechanism.