Anticonvulsant effects of Senna spectabilis on seizures induced by chemicals and maximal electroshock

Medicinal plants for epileptic seizures: Phytoconstituents, pharmacology and mechanisms revisited

ETHNOPHARMACOLOGICAL RELEVANCE

Epilepsy is a neurological disorder that presents with recurring and spontaneous seizures. It is prevalent worldwide, affecting up to 65 million people, with 80% of cases found in lower-income countries. Medicinal plants are commonly employed for managing and treating epilepsy and convulsions due to their unique therapeutic properties. With increasing research and clinical application, medicinal plants are gaining attention globally due to their potent therapeutic effects and fewer side effects. The development of new plant-based antiepileptic/anticonvulsant agents has become a major focus in the pharmaceutical industry.

AIM OF THE REVIEW

This article summarizes recent research on medicinal plants with reported antiepileptic/anticonvulsant effects. It provides pharmacological and molecular mechanism of action information for the crude extracts and related active constituents evaluated in preclinical research for the treatment of epilepsy and convulsions, and offers a reference for the development of future related studies in this area.

MATERIALS AND METHODS

Articles related to ethnopharmacological and antiepileptic studies on plants or natural products from 2018 to 2023 were collected from PubMed, Web of Science and Scopus, etc. using keywords related to epilepsy, medicinal plants, and natural products, etc. RESULTS: Eighty plant species are commonly used to treat epilepsy and convulsions in African and Asian countries. Sixty natural products showing potential for antiepileptic/anticonvulsant effects have been identified from these medicinal plants. These products can be broadly classified as alkaloids, coumarins, flavonoids, saponins, terpenoids and other compounds. The antiepileptic action of plant extracts and their active ingredients can be classified according to their abilities to modulate the GABAergic and glutamatergic systems, act as antioxidants, exhibit anti-neuroinflammatory effects, and provide neuroprotection. In addition, we highlight that some medicinal plants capable of pharmacologically relieving epilepsy and cognition may be therapeutically useful in the treatment of refractory epilepsy.

CONCLUSIONS

The review highlights the fact that herbal medicinal products used in traditional medicine are a valuable source of potential candidates for antiepileptic drugs. This confirms and encourages the antiepileptic/anticonvulsant activity of certain medicinal plants, which could serve as inspiration for further development. However, the aspects of structural modification and optimization, metabolism, toxicology, mechanisms, and clinical trials are not fully understood and need to be further explored.

Comparative LC-ESIMS-Based Metabolite Profiling of Senna italica with Senna alexandrina and Evaluating Their Hepatotoxicity

Senna Mill. (Fabaceae) is an important medicinal plant distributed worldwide. Senna alexandrina (S. alexandrina), the officinal species of the genus, is one of the most well-known herbal medicines traditionally used to treat constipation and digestive diseases. Senna italica (S. italica), another species of the genus, is native to an area ranging from Africa to the Indian subcontinent, including Iran. In Iran, this plant has been used traditionally as a laxative. However, very little phytochemical information and pharmacological reports investigating its safety of use are available. In the current study, we compared LC-ESIMS metabolite profiles of the methanol extract of S. italica with that of S. alexandrina and measured the content of sennosides A and B as the biomarkers in this genus. By this, we were able to examine the feasibility of using S. italica as a laxative agent like S. alexandrina. In addition, the hepatotoxicity of both species was evaluated against HepG2 cancer cell lines using HPLC-based activity profiling to localize the hepatotoxic components and evaluate their safety of use. Interestingly, the results showed that the phytochemical profiles of the plants were similar but with some differences, particularly in their relative contents. Glycosylated flavonoids, anthraquinones, dianthrones, benzochromenones, and benzophenones constituted the main components in both species. Nevertheless, some differences, particularly in the relative amount of some compounds, were observed. According to the LC-MS results, the amounts of sennoside A in S. alexandrina and S. italica were 1.85 ± 0.095% and 1.00 ± 0.38%, respectively. Moreover, the amounts of sennoside B in S. alexandrina and S. italica were 0.41 ± 0.12 % and 0.32 ± 0.17%, respectively. Furthermore, although both extracts showed significant hepatotoxicity at concentrations of 50 and 100 µg/mL, they were almost non-toxic at lower concentrations. Taken together, according to the results, the metabolite profiles of S. italica and S. alexandrina showed many compounds in common. However, further phytochemical, pharmacological, and clinical studies are necessary to examine the efficacy and safety of S. italica as a laxative agent.

Calcium Phosphate-Based Nanoformulation Selectively Abolishes Phenytoin Resistance in Epileptic Neurons for Ceasing Seizures

Phenytoin (PHT) is a first-line antiepileptic drug in clinics, which could decrease neuronal bioelectric activity by blocking the voltage-operated sodium channels. However, the intrinsically low blood-brain-barrier (BBB)-crossing capability of PHT and upregulated expression level of the efflux transporter p-glycoprotein (P-gp) coded by the gene Abcb1 in epileptic neurons limit its efficacy in vivo. Herein, a nanointegrated strategy to overcome PHT resistance mechanisms for enhanced antiepileptic efficacy is reported. Specifically, PHT is first incorporated into calcium phosphate (CaP) nanoparticles through biomineralization, followed by the surface modification of the PEGylated BBB-penetrating TAT peptide. The CaP@PHT-PEG-TAT nanoformulation could effectively cross the BBB to be taken in by epileptic neurons. Afterward, the acidic lysosomal environment would trigger their complete degradation to release Ca²⁺ and PHT into the cytosol. Ca²⁺ ions would inhibit mitochondrial oxidative phosphorylation to reverse cellular hypoxia to block hypoxia-inducible factor-1α (Hif1α)-Abcb1-axis, as well as disrupt adenosine triphosphate generation, leading to simultaneous suppression of the expression and drug efflux capacity of P-gp to enhance PHT retention. This study offers an approach for effective therapeutic intervention against drug-resistant epilepsy.

Chemical Profiles and In Vitro Cholinesterase Inhibitory Activities of the Flower Extracts of Cassia spectabilis

Background

Cassia spectabilis is a flowering plant containing various metabolites that provide potential for pharmacological activities. The current study aimed to investigate the ethanolic and water extracts of C. spectabilis as cholinesterase inhibitor as one of the target treatments for Alzheimer's disease. The chemical composition of the extracts was also studied to determine which components are responsible for the bioactivity.

Methods

The cholinesterase inhibitory activity assay was carried out by the modified Ellman's method against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). LC-MS/MS analysis was carried out to investigate the chemical profiles of the extracts, followed by a molecular networking study by GNPS.

Results

Both extracts showed inhibition against AChE and BChE in a dose-dependent manner, with the higher potency exhibited by the ethanolic extract with IC50 values of 7.88 and 3.78 μg/mL. The chemical analysis and molecular networking study of the flower extracts revealed similarity between the ethanolic and water extracts. Piperidine alkaloids were identified in both extracts, while the sphingolipid compounds were found in the ethanolic extract.

Conclusion

The water and ethanolic extracts of C. spectabilis flowers displayed potency for Alzheimer's disease treatment. The presence of piperidine alkaloids in the extract may be responsible for the cholinesterase inhibitory activity. The higher potency of the ethanolic extract compared to the water extract is possibly due to the higher amount of piperidine alkaloids in the ethanolic extract. Further study is needed to quantify the concentration of alkaloids in the extracts.

Sakuranetin exerts anticonvulsant effect in bicuculline-induced seizures

Epilepsy is a chronic neurological disorder characterized by an abnormal, spontaneous, and synchronized neuronal hyperactivity. Therapeutic approaches for controlling epileptic seizures are associated with pharmacoresistance and side effects burden. Previous studies reported that different natural products may have neuroprotector effects. Sakuranetin (SAK) is a flavanone with antiparasitic, anti-inflammatory, antimutagenic, antiallergic, and antioxidant activity. In the present work, the effect of SAK on seizures in a model of status epilepticus induced by bicuculline (BIC) in mice was evaluated. Male Swiss mice received an intracerebroventricular injection (i.c.v.) of SAK (1, 10, or 20 mg/kg-SAK1, SAK10, or SAK20). Firstly, animals were evaluated in the open field (OF; 20 min), afterwards in the elevated plus maze (EPM) test (5 min). Next, 30 min prior the administration of BIC (1 mg/kg), mice received an injection of SAK (1 or 10 mg/kg, i.c.v.) and were observed in the OF (20 min) for seizures assessment. After behavioral procedures, immunohistochemical analysis of c-Fos was performed. Our main results showed that the lowest doses of SAK (1 and 10 mg/kg) increased the total distance traveled in the OF, moreover protected against seizures and death on the BIC-induced seizures model. Furthermore, SAK treatment reduced neuronal activity on the dentate gyrus of the BIC-treated animals. Taken together, our results suggest an anticonvulsant effect of SAK, which could be used for the development of anticonvulsants based on natural products from herbal source.

Epilepsy research in Africa: A scoping review by the ILAE Pediatric Commission Research Advocacy Task Force

OBJECTIVE

Despite the high prevalence of epilepsy in Africa, evaluation of epilepsy research trends on the continent is lacking. Without establishing effective research, improvement in care for people with epilepsy cannot be effectively strategized or targeted.

METHODS

A scoping review of the peer-reviewed literature on epilepsy from Africa (1989-2019) was conducted. The aim was to understand from this what areas are well researched versus underresearched based on published epilepsy topics.

RESULTS

A total of 1227 publications were identified and assessed. A significant increase in publications occurred over the 30 years assessed. African author leadership was evident in most reports. Nine countries had >50 publications identified; the remaining 45 countries had <50 or no publications. Research studies were typically of lower quality (case series and observational studies). Research themes were more focused on clinical epilepsy (descriptive observational studies) and social aspects (qualitative surveys). However, there were a number of unique and strong themes, specifically for neurocysticercosis and nodding syndrome, where strong research collaborations were evident, basic science understandings were explored, and interventional models were established.

SIGNIFICANCE

Despite Africa being the continent with the most countries, it is lacking in the quantity, quality, and for some areas, relevance of research on epilepsy. Targeted approaches are needed to upskill the strength of research undertaken with more basic science, interventional, and randomized controlled studies. Themes of research need to promote those with unique African content but also to align with current international research areas that have impact on care delivery, such as epilepsy surgery and epilepsy genetics. For this to be possible, it is important to strengthen research hubs with collaborations that empower Africa to own its epilepsy research journey.

Chemical composition, in vitro cytotoxic and anticholinesterase activities of flower extracts of Senna spectabilis var. excelsa and Senna macranthera

In this study, we investigated the phenolic and antioxidant content, cytotoxic, and anticholinesterase activities of flower extracts of Senna spectabilis var. excelsa and Senna macranthera. The antioxidant activities performed by the DPPH and ABTS methods showed that the extracts possess good antioxidant activity, with emphasis on the S. macranthera extract, which obtained results very similar to the rutin pattern. In the evaluation of the cytotoxic activity, the species S. spectabilis var. excelsa presented expressive cytotoxicity against the cellular lines PC3 and HL60 with IC₅₀ values 21.08 and 31.37 μg mL^-1, respectively. The results of anticholinesterase activity showed that both the plants induced enzyme inhibition, reaching 14 mm of inhibition in the case of S. spectabilis var. excelsa. The good results obtained in this work may be related to the presence of compounds such as apigenin-7-apioglucoside, quercetin 3,4'-diglucoside, cassine and spectaline identified in the extracts in our previous work.

Pharmacognostical evaluation and anti-convulsant property of Annona reticulata Linn. (Annonaceae) root

Background

The present investigation was aimed at establishing the pharmacognostical parameters and preliminary phytochemical screening of Annona reticulata Linn. (Annonaceae) root. Pharmacognostical studies and phytochemical evaluation of A. reticulata root were carried out by following standard procedures to provide information that help to identify the species. The species of Annonaceae family are documented to possess anticonvulsant property, while A. reticulata and its root are reported to be used as a folklore medicine to treat epilepsy. In this study, anti-convulsant activity of the root extract was further investigated in mouse model with seizures induced by pentylenetetrazole (PTZ; 60 mg/kg, i.p.). Diazepam (5 mg/kg) was used as a standard anti-convulsant drug. Prior to induction of seizures, ethanol extract (100, 200, and 400 mg/kg, p.o.,) and 0.1% sodium CMC were administered. Later, the onset, duration of convulsions along with recovery was recorded.

Results

A. reticulata can be recognized by its crown shape, leaves with lengthy petioles, fleshy petals and heart-shaped fruits. Roots are cylindrical with rootlets and have aromatic odour. Presence of oil globules and rhomboidal calcium oxalate crystals in cortex, sclerenchyma cells in cortex and secondary phloem, starch grains in cortex, secondary phloem and secondary xylem, and uni- to tri-seriate medullary rays are the key diagnostic characters of root. Preliminary phytochemical screening of extracts revealed the presence of phenolic compounds, tannins, alkaloids, carbohydrates, flavonoids, glycosides, saponins, proteins, fixed oil and fats. The total alkaloid content in the root was 0.524% w/w, while total flavonoid and total phenolic content in ethanol extract were 16.65 mg QE/g and 59.54 mg GAE/g, respectively. Based on the values obtained from anti-convulsant activity, it is evident that the ethanol extract offered significant protection against PTZ-induced convulsion in mice.

Conclusion

The current pharmacognostical study aids not only in identification of crude drug material but also in establishing the standardization parameters. Further, the findings of this study indicated that the ethanolic extract of Annona reticulata Linn root displayed significant anti-convulsant property and this property could be attributed to imperative bioactives like flavonoids, phenolic compounds, alkaloids, in addition to other secondary metabolites.

Antiepileptic effects of antioxidant potent extract from Urtica dioica Linn. root on pentylenetetrazole and maximal electroshock induced seizure models

Urtica dioica Linn. (Urticaceae) is a medicinal plant that has shown various therapeutic utilities in folklore medicine along with its use in the treatment of epilepsy. The entire plant has a sensible reservoir of nutritional elements and micronutrients. The purpose of the present study was to investigate the antiepileptic effect of antioxidant potent extract of Urtica dioica root on animal models. Antioxidant activity of various solvent extracts i.e. Petroleum ether extract (PEE), Ethyl acetate extract (EAE), Chloroform extract (CE) and Ethanolic extract (EE) were screened by DPPH radical scavenging assay using Ascorbic acid as the standard. Further the most potent antioxidant extract was subjected to antiepileptic activity against MES and PTZ model. The IC₅₀ values of different Urtica dioica extracts (PEE, CE, EAE, and EE) in antioxidant assay were found to be 167.54 ± 1.97, 134.41 ± 0.82, 88.15 ± 1.39 and 186.38 ± 1.91 μg/ml in DPPH radical scavenging assay, respectively. The EAE has showed the potent antioxidant activity. In experimental study the EAE (100 and 200 mg/kg, p.o) has found to be effective and significant against MES and PTZ induced seizures. The present study also suggested that antioxidant potent extract (EAE) of Urtica dioica root has antiepileptic effect against MES and PTZ induced seizures. However, further research studies will investigate the active component(s) of Urtica dioica responsible for the observed anticonvulsant effects.

Complete chloroplast genome of Senna spectabilis (DC.) H.S. Irwin & Barneby (Fabaceae) and phylogenetic analysis

Senna spectabilis (DC.) H.S. Irwin & Barneby is a popular ornamental tree as well as a traditional medical plant in Cameroon. In this study, we sequenced and annotated the complete chloroplast genome of S. spectabilis and reconstructed the phylogenetic relationship of the tribe Cassieae. The length of the chloroplast genome was determined to be 162,754 bp, containing a pair of inverted repeats of 25,413 bp which separated by a small single-copy (SSC) region of 20,161 bp and a large single-copy (LSC) region of 91,767 bp. The cp genome encodes 128 genes, including 83 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The percentage of total GC content of this genome was 35.7%. The phylogenetic analysis indicates that S. spectabilis with the sampled Senna species formed a well-supported monophyletic clade.