Antiepileptic activity of lobeline isolated from the leaf of Lobelia nicotianaefolia and its effect on brain GABA level in mice

Multispectroscopic and Theoretical Investigation on the Binding Interaction of a Neurodegenerative Drug, Lobeline with Human Serum Albumin: Perturbation in Protein Conformation and Hydrophobic-Hydrophilic Surface

Lobeline (LOB), a naturally occurring alkaloid, has a broad spectrum of pharmacological activities and therapeutic potential, including applications in central nervous system disorders, drug misuse, multidrug resistance, smoking cessation, depression, and epilepsy. LOB represents a promising compound for developing treatments in various medical fields. However, despite extensive pharmacological profiling, the biophysical interaction between the LOB and proteins remains largely unexplored. In the current article, a range of complementary photophysical and cheminformatics methodologies were applied to study the interaction mechanism between LOB and the carrier protein HSA. Steady-state fluorescence and fluorescence lifetime experiments confirmed the static-quenching mechanisms in the HSA-LOB system. "K" (binding constant) of the HSA-LOB system was determined to be 105 M-1, with a single preferable binding site in HSA. The forces governing the HSA-LOB stable complex were analyzed by thermodynamic parameters and electrostatic contribution. The research also investigated how various metal ions affect complex binding. Site-specific binding studies depict Site I as probable binding in HSA by LOB. We conducted synchronous fluorescence, 3D fluorescence, and circular dichroism studies to explore the structural alteration occurring in the microenvironment of amino acids. To understand the robustness of the HSA-LOB complex, we used theoretical approaches, including molecular docking and MD simulations, and analyzed the principal component analysis and free energy landscape. These comprehensive studies of the structural features of biomolecules in ligand binding are of paramount importance for designing targeted drugs and delivery systems.

The effect of valproate on the amino acids, monoamines, and kynurenic acid concentrations in brain structures involved in epileptogenesis in the pentylenetetrazol-kindled rats

BACKGROUND

The study aimed to assess the influence of a single valproate (VPA) administration on inhibitory and excitatory neurotransmitter concentrations in the brain structures involved in epileptogenesis in pentylenetetrazol (PTZ)-kindled rats.

METHODS

Adult, male Wistar rats were kindled by repeated intraperitoneal (ip) injections of PTZ at a subconvulsive dose (30 mg/kg, three times a week). Due to the different times required to kindle the rats (18-22 injections of PTZ), a booster dose of PTZ was administrated 7 days after the last rats were kindled. Then rats were divided into two groups: acute administration of VPA (400 mg/kg) or saline given ip. The concentration of amino acids, kynurenic acid (KYNA), monoamines, and their metabolites in the prefrontal cortex, hippocampus, amygdala, and striatum was assessed by high-pressure liquid chromatography (HPLC).

RESULTS

It was found that a single administration of VPA increased the gamma-aminobutyric acid (GABA), tryptophan (TRP), 5-hydroxyindoleacetic acid (5-HIAA), and KYNA concentrations and decreased aspartate (ASP) levels in PTZ-kindled rats in the prefrontal cortex, hippocampus, amygdala and striatum.

CONCLUSIONS

Our results indicate that a single administration of VPA in the PTZ-kindled rats restored proper balance between excitatory (decreasing the level of ASP) and inhibitory neurotransmission (increased concentration GABA, KYNA) and affecting serotoninergic neurotransmission in the prefrontal cortex, hippocampus, amygdala, and striatum.

A review on epilepsy, current treatments, and potential of medicinal plants as an alternative treatment

Epilepsy is considered common neurological diseases that threaten the lives of millions of people all around the world. Since ancient times, different forms of medications have been used to treat this condition. Adverse events associated with treatments and the residence time of available drugs caused to search for safer and more efficient therapies and drugs remain one of the major areas of research interest for scientists. As one of the therapeutics with fewer side effects, plants and their essential oils can be considered replacements for existing treatments. Medicinal plants have proven to be an effective natural source of antiepileptic drugs; most of them have their mechanism of action by affecting GABA receptors in different paths. Cannabis indica and Cymbopogon winterianus are well-known plant species with antiepileptic activities. The current review presenting a list of plants with antiepileptic effects aims to pave the way for finding alternative drugs with fewer side effects for scientists.

Anticonvulsant potential of Grewia tiliaefolia in pentylenetetrazole induced epilepsy: insights from in vivo and in silico studies

Epilepsy, a chronic neurological condition, impacts millions of individuals globally and remains a significant contributor to both illness and mortality. Available antiepileptic drugs have serious side effects which warrants to explore different medicinal plants used for the management of epilepsy reported in Traditional Indian Medicinal System (TIMS). Therefore, we explored the antiepileptic potential of the Grewia tiliaefolia (Tiliaeceae) which is known for its neuroprotective properties. Aerial parts of G. tiliaefolia were subjected to extraction with increasing order of polarity viz. hexane, chloroform and methanol. Antioxidant potential of hexane, chloroform and methanol extracts of G. tiliaefolia was evaluated by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay, total antioxidant capacity (TAC) assay, reducing power assay (RPA) and DNA nicking assay. Additionally, quantitative antioxidant assays were also conducted to quantify total phenolic (TPC) and total flavonoid content (TFC). As revealed by in vitro assays, methanol extract was found to contain more phenolic content. Hence, the methanol extract was further explored for its anticonvulsant potential in pentylenetetrazole (PTZ) induced acute seizures in mice. The methanol extract (400 mg/kg) significantly increased the latency to occurrence of myoclonic jerks and generalized tonic clonic seizures (GTCS). Additionally, it also reduced duration and seizure severity score associated with GTCS. The Grewia tiliaefolia methanol extract was further screened by Ultra High-Performance Liquid Chromatography (UHPLC) for presence of polyphenolic compounds, among which gallic acid and kaempferol were present in higher amount and were further analysed by in silico study to predict their possible binding sites and type of interactions these compounds show with gamma amino butyric acid (GABA) receptor and glutamate α amino-3- hydroxyl-5-methyl-4-isoxazolepropionic acid (Glu-AMPA) receptor. It was revealed that gallic acid and kaempferol had shown agonistic interaction for GABA receptor and antagonistic interaction for Glu-AMPA receptor. We concluded that G. tiliaefolia showed anticonvulsant potential possibly because of gallic acid and kaempferol possibly mediated through GABA and Glu-AMPA receptor.

Lobeline: A multifunctional alkaloid modulates cholinergic and glutamatergic activities

Developing drugs for Alzheimer's disease (AD) is an extremely challenging task due to its devastating pathology. Previous studies have indicated that natural compounds play a crucial role as lead molecules in the development of drugs. Even though, there are remarkable technological advancements in the isolation and synthesis of natural compounds, the targets for many of them are still unknown. In the present study, lobeline, a piperidine alkaloid has been identified as a cholinesterase inhibitor through chemical similarity assisted target fishing method. The structural similarities between lobeline and donepezil, a known acetylcholinesterase (AChE) inhibitor encouraged us to hypothesize that lobeline may also exhibit AChE inhibitory properties. It was further confirmed by in silico, in vitro and biophysical studies that lobeline could inhibit cholinesterase. The binding profiles indicated that lobeline has a higher affinity for AChE than BChE. Since excitotoxicity is one of the major pathological events associated with AD progression, we also investigated the neuroprotective potential of lobeline against glutamate mediated excitotoxicity in rat primary cortical neurons. The cell based NMDA receptor (NMDAR) assay with lobeline suggested that neuroprotective potential of lobeline is mediated through the blockade of NMDAR activity.

Treating Epilepsy with Natural Products: Nonsense or Possibility?

Epilepsy is a neurological disease characterized by recurrent seizures that can lead to uncontrollable muscle twitching, changes in sensitivity to sensory perceptions, and disorders of consciousness. Although modern medicine has effective antiepileptic drugs, the need for accessible and cost-effective medication is urgent, and products derived from plants could offer a solution. For this review, we have focused on natural compounds that have shown anticonvulsant activity in in vivo models of epilepsy at relevant doses. In some cases, the effects have been confirmed by clinical data. The results of our search are summarized in tables according to their molecular targets. We have critically evaluated the data we present, identified the most promising therapeutic candidates, and discussed these in the text. Their perspectives are supported by both pharmacokinetic properties and potential interactions. This review is intended to serve as a basis for future research into epilepsy and related disorders.

Plastome evolution in the East Asian lobelias (Lobelioideae) using phylogenomic and comparative analyses

Lobelia species, as rich source of the alkaloid lobeline which has been shown to have important biological activity, have been used in folk medicine throughout East Asia to treat various diseases. However, Lobelia is a complex and varied genus in East Asia and is thus difficult to identify. Genomic resources would aid identification, however the availability of such information is poor, preventing a clear understanding of their evolutionary history from being established. To close this gap in the available genomic data, in this study, 17 plastomes of East Asian lobelias were newly sequenced and assembled. Although the plastomes of Lobelia sect. Hypsela, L. sect. Speirema, and L. sect. Rhynchopetalum shared the gene structure, the inverted repeat (IR)/large single copy (LSC) boundaries, genome size, and the number of repeats were variable, indicating the non-conservative nature of plastome evolution within these sections. However, the genomes of the Lobelia sect. Delostemon and L. sect. Stenotium showed rearrangements, revealing that these two sections might have undergone different evolutionary histories. We assessed nine hotspot genes and 27-51 simple sequence repeat motifs, which will also serve as valuable DNA barcode regions in future population genetics studies and for the delineation of plant species. Our phylogenetic analysis resolved the evolutionary positions of the five sections in agreement with previous evolutionary trees based on morphological features. Although phylogenetic reconstruction of Lobelioideae based on the rpoC2 gene has rarely been performed, our results indicated that it contains a considerable amount of phylogenetic information and offers great promise for further phylogenetic analysis of Lobelioideae. Our site-specific model identified 173 sites under highly positive selections. The branch-site model exhibited 11 positive selection sites involving four genes in the East Asian branches. These four genes may play critical roles in the adaptation of East Asian taxa to diverse environments. Our study is the first to detect plastome organization, phylogenetic utility, and signatures of positive selection in the plastomes of East Asian lobelias, which will help to further advance taxonomic and evolutionary studies and the utilization of medicinal plant resources.

Antidepressant Activities of Synthesized Benzodiazepine Analogues in Mice

Depression is a serious psychological disorder which negatively affects human feelings and actions. The use of antidepressants is the therapy of choice while treating depression. However, such drugs are associated with severe side effects. There is a need for efficient and harmless drugs. In this connection, the present study was designed to synthesize several substituted benzodiazepine derivatives and explore their antidepressant potentials in an animal model. The chalcone backbone was initially synthesized, which was then converted into several substituted benzodiazepine derivatives designated as 1-6. The synthesized compounds were identified using spectroscopic techniques. The experimental animals (mice) after acclimatation were subjected to forced swim test (FST) and tail suspension test (TST) after oral administration of the synthesized compounds to evaluate their antidepressant potentials. At the completion of the mentioned test, the animals were sacrificed to determine GABA level in their brain hippocampus. The chloro-substituent compound (2) significantly reduced the immobility time (80.81 ± 1.14 s; p < 0.001 at 1.25 mg/kg body weight and 75.68 ± 3.73 s with p < 0.001 at 2.5 mg/kg body weight dose), whereas nitro-substituent compound (5) reduced the immobility time to 118.95 ± 1.31 and 106.69 ± 3.62 s (p < 0.001), respectively, at the tested doses (FST). For control groups, the recorded immobility time recorded was 177.24 ± 1.82 s. The standard drug diazepam significantly reduced immobility time to 70.13 ± 4.12 s while imipramine reduced it to 65.45 ± 2.81 s (p < 0.001). Similarly, in the TST, the compound 2 reduced immobility time to 74.93 ± 1.14 s (p < 0.001) and 70.38 ± 1.43 s (p < 0.001), while compound 5 reduced it to 88.23 ± 1.89 s (p < 0.001) and 91.31 ± 1.73 s (p < 0.001) at the tested doses, respectively, as compared to the control group immobility time (166.13 ± 2.18 s). The compounds 1, 3, 4, and 6 showed weak antidepressant responses as compared to compounds 2 and 5. The compounds 2 and 5 also significantly enhanced the GABA level in the brain's hippocampus of experimental animals, indicating the possible involvement of GABAergic mechanism in alleviating the depression which is evident from the significant increase in mRNA levels for the α subunit of the GABA_A receptors in the prefrontal cortex of mice as well. From the results, it can be concluded that compound 2 and 5 could be used as alternative drugs of depression. However, further exploration in this connection is needed in other animal models in order to confirm the observed results in this study.

Prunin modulates the Expression of Cerebral Serotonin Induced by Anxiety-Like Behavior in Mice

Anxiety is a state that becomesa disorder when a person experiences disproportionate levels of anxiety on a regular basis. This disproportion is also accompanied by excessive nervousness and fear. This study aimed to determine the protective effect of prunin using different anxiety models. Three preclinical anxiety models, elevated plus maze, light/dark, and social interaction, were employed in the study. Albino mice were selected and treated with pruninand other drugs for 7 days to determine their anti-anxiety effect. Thereafter, their behavior was examined using the plus maze, light-dark chamber, and other stimulatory parameters, such asimmobility, sniffing, and crawling during experimentation. Two doses (50 mg/kg and 100 mg/kg, p.o.) of prunin were administered to two separate mice groups. Further, fluoxetine (10 mg/kg; p.o.) was administered to one of the mice groups for 7 days. Thereafter, the levels of neurotransmitters, such as serotonin and GABA, in brain samples were determined. Based on the results, prunin significantly improved the behavior and mobility of animals in all three anxiety models. Further, prunin modulated the release of serotonin and GABA, demonstrating the mechanistic approach it employs to interact with cellular receptors to mimic neurotransmission. The mRNA expression levels of tph2 (5-HT synthesizing enzyme) and slc6a4 (5-HT transporter) were also found to be downregulated in both prunin- and fluoxetine-treated mice brains. Collectively, our findings suggest that prunin could be administered to treat anxiety in mice. However, further studies should be carried out to explore its potential for clinical application.

Stigmasterol can be new steroidal drug for neurological disorders: Evidence of the GABAergic mechanism via receptor modulation

BACKGROUND

Gamma-aminobutyric acid A (GABA_A) receptors have been implicated in anxiety and epileptic disorders.

HYPOTHESIS/PURPOSE

This study aimed to investigate the effects of stigmasterol, a plant sterol (phytosterol) isolated from Artemisia indica Linn on neurological disorders.

METHODS

Stigmasterol was evaluated on various recombinant GABA_A receptor subtypes expressed in Xenopus laevis oocytes and its anxiolytic and anticonvulsant potential was assessed using the elevated plus maze (EPM), light-dark box (LDB) test, and pentylenetetrazole- (PTZ-) induced seizure paradigms. Furthermore, computational modeling of α2β2γ2L, α4β3δ, and α4β3 subtypes was performed to gain insights into the GABAergic mechanism of stigmasterol. For the first time, a model of GABAδ subtype was generated. Stigmasterol was targeted to all the binding sites (neurotransmitters, positive and negative modulator binding sites) of GABA_A α2β2γ2L, α4β3, and α4β3δ complexes by in silico docking.

RESULTS

Stigmasterol enhanced GABA-induced currents at ternary α2β2γ2L, α4β3δ, and binary α4β3 GABA_AR subtypes. The potentiation of GABA-induced currents at extrasynaptic α4β3δ was significantly higher compared to the binary α4β3 subtype, indicating that the δ subunit is important for efficacy. Stigmasterol was found to be a potent positive modulator of the extrasynaptic α4β3δ subtype, which was also confirmed by computational analysis. The computational analysis reveals that stigmasterol preferentially binds at the transmembrane region shared by positive modulators or a binding site constituted by the M2-M3 region of α4 and M1-M2 of β3 at α4β3δ complex. In in vivo studies, Stigmasterol (0.5-3.0 mg/kg, i.p.) exerted significant anxiolytic and anticonvulsant effects in an identical manner of allopregnanolone, indicating the involvement of a GABAergic mechanism.

CONCLUSION

To our knowledge, this is the first study reporting the positive modulation of GABA_A receptors, anxiolytic and anticonvulsant potential of stigmasterol. Thus, stigmasterol is considered to be a candidate steroidal drug for the treatment of neurological disorders due to its positive modulation of GABA receptors.

Effect of 70% Ethanol Extract and its Solvent Fractions of Artemisia afra (Jacq. Ex Willd.) against Pentylenetetrazole-Induced Seizure in Mice

INTRODUCTION

Artemisia afra (Jacq. ex Willd.), commonly called African wormwood, is a highly aromatic perennial herb and a well-known medicinal plant, claimed to be effective and safe in the treatment of epilepsy. The whole-plant extract is traditionally used as an antiepileptic agent in Ethiopia. Aim of the Study. The aim of this study was, therefore, to evaluate the anticonvulsant effect of the hydroethanolic extract and solvent fractions of A. afra whole part in mice.

MATERIALS AND METHODS

The effects of A. afra hydroethanolic extract and its solvent fractions were evaluated against pentylenetetrazole- (PTZ-) induced convulsions in mice. The onset and duration of PTZ-induced convulsions were determined with hydroethanolic A. afra extract and its solvent fractions. Data were analyzed using a one-way analysis of variance (ANOVA) followed by post hoc Tukey's multiple comparisons test. p < 0.05 was considered statistically significant.

RESULTS

The hydroethanolic extract of A. afra, with all the three doses of 250, 500, and 1000 mg/kg, showed a significant delay (504.833 ± 62.835 ∗  s; p < 0.05 ∗ ; 551.833 ± 47.69 ∗∗  s; p < 0.01 ∗∗ ; and 808.333 ± 64.8 ∗∗∗ s; p < 0.001 ∗∗∗ , respectively) in the mean onset of convulsion and a decrease (17.000 ± 1.88 ∗∗∗  s, p < 0.05 ∗ ; 13.000 ± 1.8 ∗∗  s, p < 0.01 ∗∗ ; and 7.833 ± 1.07 ∗∗∗  s, p < 0.001, respectively) in the mean duration of convulsion against PTZ-induced convulsion in a dose-dependent manner compared to the control (92.833 ± 13.006 s; 34.167 ± 3.683 s), and its anticonvulsant activity was significantly less compared to that of diazepam (1001.167 ± 68.430 s; 4.500 ± 0.619 s). The solvent fractions, however, did not show anticonvulsant activity against PTZ-induced convulsion.

CONCLUSION

Crude extract of A. afra has an anticonvulsant effect in mice. This might be attributed to the synergistic effects of two or more active ingredients present in the herb.

Beyond Alkaloids: Novel Bioactive Natural Products From Lobelia Species

In this work, we reviewed the progress in the phytochemical and biological investigations of bioactive components derived from medicinally valuable Lobelia species. In the last 60 years, Lobelia has garnered significant attention from the phytochemist from around the world, majorly due to the discovery of bioactive piperidine alkaloids (e.g., lobinaline and lobeline) in the early 1950s. Later, lobeline underwent clinical trials for several indications including the treatment of attention deficit hyperactivity disorder and a multicenter phase three trial for smoking cessation. Subsequently, several other alkaloids derived from different species of Lobelia were also investigated for their pharmacological characteristics. However, in the last few years, the research focus has started shifting to the characterization of the other novel chemical classes. The major shift has been noticed due to the structurally similar alkaloid components, which essentially share similar pharmacological, physicochemical, and toxicological profiles. In this review, we present an up-to-date overview of their progress with special attention to understanding the molecular mechanisms of the novel bioactive components.

Nanoformulated ellagic acid ameliorates pentylenetetrazol-induced experimental epileptic seizures by modulating oxidative stress, inflammatory cytokines and apoptosis in the brains of male mice

The present study evaluated the neuroprotective and antiepileptic efficacy of ellagic acid (EA) encapsulated in calcium-alginate nanoparticles (Ca²⁺-ALG NPs) in pentylenetetrazol (PTZ)-induced seizures in male mice. EA was encapsulated in ALG NPs using a nanospray drying method followed by ionotropic crosslinking with Ca²⁺. Characterization of the developed Ca²⁺-crosslinked EA-ALG NPs showed spherical, high stability NPs; successful loading of EA within crosslinked ALG NPs; and sustained release of EA. Male Swiss albino mice were divided into ten groups as follows; Group I- (control), Group II (50 mg EA /kg) - (EA), Group III polyethylene glycol (PEG), Group IV EA NPs (50 mg/kg) - (EA NP), Group (50 mg/kg alginate) V void V NPs - (void NPs), Group VI: (37.5 PTZ mg/kg) -(PTZ), Group VII: PTZ and EA - (PTZ-EA). Group VIII: animals received PTZ and PEG concurrently (PTZ-PEG). Group IX; animals received PTZ and void NPs concurrently - (PTZ-void). Group X: animals received PTZ and EA NPs concurrently (PTZ-EA NPs). PTZ was used to induce experimental epilepsy. Ca²⁺-ALG NPs prevented seizures throughout the experimental period and had a more prominent effect than free EA did. Ca²⁺-ALG NPs prevented increased glutamate, decreased GABA concentrations and ameliorated increased amyloid-β and homocysteine levels in the serum and brain. Ca²⁺-EA-ALG NPs were superior to free EA in improving increased IL-6 and TNF-α. Ca²⁺-ALG NPs ameliorated PTZ-induced oxidative stress, as evidenced by decreased 4HNE levels and enhanced GSH, GR and GPx levels in the brain. These changes were accompanied by amelioration of apoptosis and its regulating proteins, including Cytochrome C, P53, Bax, Bcl2 and caspase-3 and caspase-9, and protected against DNA damage. Histological examination of the hippocampus confirmed that the neuroprotective effect of Ca²⁺-EA-ALG NPs was superior and more effective than that of free EA.

Anticonvulsant and Neuroprotective Effects of Paeonol in Epileptic Rats

Paeonol is the main active compound in the root bark extract of the peony tree, and it has antioxidative and anti-inflammatory effects. Recent studies have reported the neuroprotective effects of paeonol including its capacity in improving impaired memory. However, the effect of paeonol on epilepsy is yet to be demystified. We aimed to investigate the therapeutic effect of paeonol in epilepsy and its relationship with oxidative stress damage and neuronal loss in the rat brain to reveal the underlying mechanisms of epileptic seizures. A rat model for chronic epilepsy was established, and the seizure scores of the rats in different groups were recorded. The seizure duration and the seizure onset latency were used to evaluate the anticonvulsant effects of paeonol. Terminal deoxynucleotidyl transferase dUTP nick end-labeling staining, Nissl staining and H/E staining were used to evaluate the effects of paeonol on neuronal loss and apoptosis in epileptic rats. The colorimetric assessment of malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, catalase activity and total antioxidant capacity of paeonol were used in assessing paeonol's effect on oxidative stress in epileptic rats. Evaluation of Caspase-3 mRNA and protein expression levels were determined using western blot and quantitative real-time (RT-q)PCR. In this study, we found that paeonol reduced the seizure scores of epileptic rats and attenuated the duration and onset latency of seizures. Paeonol can also increase the activities of total antioxidant capacity, SOD and catalase activity and reduce MDA content as well. This suggests that paeonol can improve the level of oxidative stress in rats. More significantly, paeonol can improve neuronal loss and apoptosis in epileptic rats. These results indicate that paeonol has anticonvulsant and neuroprotective effects in epileptic rats. This effect may be caused by reducing oxidative stress.

Evidence for the involvement of a GABAergic mechanism in the effectiveness of natural and synthetically modified incensole derivatives in neuropharmacological disorders: A computational and pharmacological approach

In the course of our continuing exploration for novel bioactive lead compounds (s) from the species Boswellia, we have recently reported incensole derivatives isolated from Boswellia papyrifera Hochst. Given the known antidepressant-like effects of incensole and incensole acetate, we herein present that the low dose intraperitoneal administration of incensole derivatives, namely, incensfuran and incensone, showed significant antidepressant-like effects in the forced swim test (FST) and tail suspension test (TST). Furthermore, these compounds were evaluated for their anxiolytic potential in the elevated plus maze (EPM) and light dark box (LDB) tests and anticonvulsant effects in pentylenetetrazole (PTZ)-induced seizure tests. In the EPM test, administration of these compounds led to dose-dependent increases in open arm entries and in the time spent in EPM open arms. Similar results were obtained in the LDB test, wherein compounds these caused significant increases in the number of transitions between lit and dark compartments and the time spent in the lit compartment. The anxiolytic-like effects in the EPM were not reversed by pretreatment with flumazenil, whereas PTZ and bicuculline (BIC) completely abolished the anxiolytic effects, showing the involvement of the non-benzodiazepine binding sites of GABA_A receptors. All four compounds induced significantly elevated brain GABA levels, indicating the involvement of a GABAergic mechanism. Additionally, molecular docking was conducted to elucidate the mode of action for the anxiolytic and anticonvulsant effects of these derivatives. Moreover, these compounds also possess drug-like properties and excellent ADMET profiles.

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.

DNA damage and oxidative stress induced by seizures are decreased by anticonvulsant and neuroprotective effects of lobeline, a candidate to treat alcoholism

The alkaloid lobeline (Lob) has been studied due to its potential use in treatment of drug abuse. This study evaluates the possible anticonvulsant and neuroprotective activities of Lob to obtain new information on its properties that could confirm it as a candidate in the treatment of alcohol addiction. The anticonvulsant effect of Lob was evaluated using a pilocarpine-induced seizure model. In addition, possible neuroprotective effects were investigated measuring DNA damage using the comet assay, assessing free radical levels by dichlorofluorescein diacetate (DCF) oxidation, and measuring the antioxidant potential using the α, α-diphenyl-β-picrylhydrazyl (DPPH) scavenging assay, besides measuring superoxide dismutase (SOD) and catalase (CAT) enzyme activities in brain tissues. Lobeline increased the latency to the first seizure and decreased the percentage of seizures in a similar way as diazepam, used as control. DNA damage induced by Pil and hydrogen peroxide were decreased in hippocampus and cerebral cortex from mice treated with Lob. The levels of free radicals and CAT activity increased in cortex and hippocampus, respectively, in mice treated with Pil. Lobeline decreased CAT in hippocampus, leading to similar values as in the saline negative control. In conclusion, Lob has anticonvulsant and neuroprotective actions that may be mediated by antioxidant-like mechanisms, indicating its potential as candidate drug in alcoholism therapy.

Recent Advances in Antiepileptic Herbal Medicine

BACKGROUND

Epilepsy is one of the most common neurological disorders worldwide, with about 80 percent of cases thought to be in developing nations where it is mostly linked to superstition. The limited supply, high cost as well as low efficacy and adverse side effects of antiepileptic drugs (AEDs) is a matter of major concern. Herbal medicine has always been traditionally part of treatment of epilepsy. Herbal medicines are generally well tolerated, with fewer side effects.

METHOD

To highlight some herbal extracts that have been studied for their anticonvulsant activity in animal models, literature search from PubMed and Science Direct, was performed. The keywords for the search consisted of combinations of the following terms: Herbal antiepileptic and/or anticonvulsant, botanicals + epilepsy. Literature published in the last five years was considered.

RESULTS

Eighteen (18) anticonvulsant herbal agents are reported and discussed. Experiments mostly consisted of phenotypic screens in rodents, with little diversity in screening methods. In most experiments, the tested extracts prolonged the time to onset of seizures and decreased their duration. Most experimenters implicate potentiation of GABAergic activity as the mode of action of the extracts, even though some experimenters did not fully characterise the bioactive chemical composition of their extracts.

CONCLUSION

Potential herbal remedies have shown positive results in animal models. It remains unclear how many make it into clinical trials and eventually making part of the AED list. More rigorous research, applying strict research methodology with uniform herbal combinations, as well as clinical studies are urgently needed.

Comparative morphology of the leaf epidermis in Lobelia (Lobelioideae) from China

The leaf epidermal morphology of 38 samples, representing 22 Lobelia species from China, was studied using light microscopy and scanning electron microscopy. The stomata and other epidermal features were largely consistent within species, and therefore represented good characters for taxonomic purposes. Diagnostic characters of the leaf epidermis were used to differentiate species of Lobelia. The species pairs L. clavata and L. pyramidalis, L. alsinoides and L. terminalis, and L. davidii and L. erectiuscula, were differentiated using leaf epidermal characters. Results at the micro-structural level partly supported the current subdivisions of Lobelia. Previous taxonomic revisions of Lobelia in China were evaluated based on species epidermal characteristics. The results supported the recognition of Pratia merged with Lobelia, and of L. chevalieri as a distinct species. Lobelia brevisepala should not be included in L. montana. The status of Lobelia in the evolutionary history of Campanulaceae was assessed. The Lobelia species investigated retained many primitive leaf epidermal features.

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.

Ferulic acid exhibits antiepileptogenic effect and prevents oxidative stress and cognitive impairment in the kindling model of epilepsy

AIMS

Some conventional antiepileptic drugs induce oxidative stress and cognitive impairment which may limit their clinical applications. Ferulic acid is a phenolic phytochemical with antioxidant and neuroprotective properties that prompted us to evaluate its therapeutic potential in epilepsy which is usually associated with oxidative stress and cognitive decline.

MATERIALS AND METHODS

Male Wistar rats received 30mg/kg of pentylenetetrazole (PTZ) intraperitoneally (i.p.) once every alternate day until the development of kindling. The locomotor activity, elevated plus maze, and passive avoidance tests were performed. Oxidative stress was evaluated by the determination of brain malondialdehyde and reduced glutathione. The effects of pre-treatment with ferulic acid (25, 50, 75, and 100mg/kg, i.p.) against PTZ-kindled seizures, cognitive impairment, and oxidative stress were investigated.

KEY FINDINGS

Kindling was developed 34.18±1.54days after PTZ treatment which was associated with generalized tonic-clonic seizures (GTCS), myoclonic jerks, cognitive deficit, and oxidative stress. Ferulic acid at doses of 75 and 100mg/kg significantly reduced the seizure score, number of myoclonic jerks, cognitive decline and oxidative stress. Spontaneous locomotor activity did not significantly differ between the groups.

SIGNIFICANCE

Ferulic acid exhibits antiepileptogenic effect and prevents oxidative stress and cognitive impairment induced by PTZ kindling. Therefore, this phenolic phytochemical appears as a promising adjuvant for antiepileptic drugs. Meanwhile, further experimental and clinical studies are required to provide insights into the cellular/molecular mechanism(s) underlying the action of ferulic acid.

Tobacco smoking, epilepsy, and seizures

Tobacco smoking is considered the greatest risk factor for death caused by noncommunicable diseases. In contrast to extensive research on the association between tobacco smoking and diseases such as heart attack, stroke, and cancers, studies on the association between tobacco smoking and seizures or epilepsy are insufficient. The exact roles tobacco smoking and nicotine use play in seizures or epilepsy have not been well reviewed. We reviewed available literature and found that 1) there are vast differences between tobacco smoke and nicotine based on their components and their effects on seizures or epilepsy; 2) the seizure risk in acute active tobacco smokers, women who smoke during pregnancy, electronic cigarette smokers, and the role of smoking in sudden unexplained/unexpected death in epilepsy remain unclear; 3) seizure risks are higher in acute secondhand smokers, chronic active smokers, and babies whose mothers smoke; 4) tobacco smoke protects against seizures in animal models whereas nicotine exerts mixed effects in animals; and 5) tobacco smoking agents can be noneffective, proconvulsant, or anticonvulsant. Finally, the opportunities for future research on this topic is discussed.

Sedative and anesthetic activities of the essential oils of Hyptis mutabilis (Rich.) Briq. and their isolated components in silver catfish (Rhamdia quelen)

This study evaluated the sedative and anesthetic effects of the essential oils (EO) of Hyptis mutabilis (Rich.) Briq. and their isolated components on silver catfish (Rhamdia quelen). Quantitative chemical differences between the EOs obtained from leaves and inflorescences were verified, and a new chemotype rich in globulol was described. Although there were no significant differences in the time of induction for sedation and anesthesia between the EOs, only the leaf EO at 344 mg/L anesthetized all fish without side effects. Fractionation of the leaf EO was carried out by column chromatography. The isolated compounds [(+)-1-terpinen-4-ol and (-)-globulol] showed different activity from that detected for the leaf EO in proportional concentrations and similar sedation to a eugenol control at 10 mg/L. However, fish exposed to 1-terpinen-4-ol (3 and 10 mg/L) did not remain sedated for 30 min. Anesthesia was obtained with 83-190 mg/L globulol, but animals showed loss of mucus during induction and mortality at these concentrations. Synergism of the depressor effects was detected with the association of globulol and benzodiazepine (BDZ), compared with either drug alone. Fish exposed to BDZ or globulol+BDZ association showed faster recovery from anesthesia in water containing flumazenil, but the same did not occur with globulol. In conclusion, the use of globulol in aquaculture procedures should be considered only at sedative concentrations of 10 and 20 mg/L, and its mechanism of action seems not to involve the GABAA-BDZ system.