Efficacy of Cicuta virosa medicinal preparations against pentylenetetrazole-induced seizures
Graphical abstract
Introduction
Impacting nearly 70 million people worldwide, epilepsy represents a complex neurological scenario characterized by recurrent seizure episodes, increased vulnerability to physical trauma, and associated comorbidities [1], [2], [3], [4], [5], [6]. Progressive brain damage due to epileptic seizures disrupts the coherence of neuronal efflux [7], [8], [9], [10], [11] and elevates the brain oxidative stress load thereby upregulating the intracellular Ca2+ concentration [12], [13] and hence facilitating for unhindered seizure progression. This imparts a significant therapeutic relevance to the potential antioxidants in context of the treatment and control of epileptic seizures [1], [14].
Conventional antiepileptic drugs (AEDs) have been the primary option for treatment and control of epileptic seizures [11]. With around 20 AEDs licensed globally, these chemical agents have shown reasonable seizure suppression potential [15]. However, their action is primarily symptomatic and thus does not address the latent biochemical alterations associated with epileptogenesis [16]. Due to this, nearly 30% of the patients do not respond to these AEDs while many experience various side effects that range from mild and short-term behavioral alteration to more severe and long-term psychiatric abnormality [11] including the possibility of seizure exacerbation [17]. This makes it imperative to search for more viable therapeutic alternative. In this context, natural product-based agents and therapies, including herbal extracts and homeopathic formulations, have shown competent potential in controlling epileptic seizures without inducing significant side effects [1], [11], [18], [19], [20], [21] therefore paving the way forward.
Cicuta virosa (CV) in one such natural remedy that is used against myriad of disorders in traditional system of medicine [18]. It has been recognized as a therapeutic option against epileptic convulsions in Materia Medica by Adolf zur Lippe (1854), John Henry Clarke (1902), James Tyler Kent (1905), and Cyrus Maxwell Boger (1915). Cicuta virosa, belonging to Apiaceae family, has Cicutoxin as one of the major contents which can regulate potassium channel currents [22] that are known to have direct effects on neuronal excitability and indirect effects related to metabolism [23] besides facilitating for cell membrane repolarization and sustained neuronal output [24]. Owing to its natural origin and documented usage, CV can be a viable alternative to conventional AEDs like Topiramate and Retigabine that act through potassium channel regulation and are known to induce behavioral and psychiatric side effects like somnolence, vision alterations, cognitive decline, and anorexia [25], [26], [27], [28], [29], [30], [31], [32]. Such effects have also been observed in healthy subjects [33] and thus put into perspective the need for competent and safer option.
Wide application in the traditional system of medicine and documented literature motivated us to investigate the efficacy of Cicuta virosa homeopathic medicinal preparations (HMPs) in PTZ-induced acute and kindling seizure models, respectively. The acute seizure model is a widely accepted tool for the screening of anticonvulsant drugs while the kindling model closely resembles the progressive neurochemical alterations, i.e. compromised functioning of GABAergic and glutamatergic transmission system and induction of pro-oxidative and pro-inflammatory responses that affect the cortical network and limbic circuit, associated with epilepsy and thus provides reliable and predictable results [34], [35], [36], [37]. Here, we evaluated the efficacy of CV HMPs in PTZ-induced acute seizure model which was followed by the assessment of HMPs in PTZ-induced kindling model. Clonazepam and sodium valproate were used as reference drugs in acute and kindling models, respectively as the former facilitates for screening of drugs for anticonvulsant action through direct action on GABAergic neurotransmission [38], [39] while the latter, owing to its multipronged action on seizure propagation [40] and active regulation of epileptogenesis [41], provides a justified benchmark for the assessment of antiepileptogenic potential of CV. Three different potencies (6CH, 12CH, and 30CH) of the HMPs were used in the study and all the potencies were in Hahnemannian centesimal (CH) dilution. Kindling assessment of the HMPs was followed with the evaluation of their efficacy in negating PTZ-induced behavioral alterations through various validated behavioral screening tests. Five tests were performed in this study for the assessment of cognition impairment, recognition memory, anxiety and behavioral normalcy, motor coordination impairment, and spatial memory retention. Utilization of multiple behavioral screening tests in epilepsy studies for the assessment of various behavioral parameters has been reported previously [42], [43], [44], [45], [46], [47], [48]. The HMPs were then assessed for their effect on brain oxidative stress through the measurement of malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) levels. The present study provides a pharmacological basis to the use of CV in traditional system of medicine and adds up to the current knowledge about its neurochemical interaction in the brain.
Section snippets
Homeopathic medicinal preparations (HMPs) of Cicuta virosa
The CV HMPs were obtained from Dr. Willmar Schwabe India Private Limited in three potencies in centesimal dilutions (6CH, 12CH, and 30CH). The HMPs were prepared as per the method described in the Homeopathic Pharmacopoeia of India (HPI). Initial CV extract (mother tincture) was prepared from the root of plant (100 g) using 500-ml purified water and 537-ml ethanol (95%) with simple percolation process. The mother tincture extract is made with a drug strength of 1/10 (100 g/1000 mL) as per the
Effect of CV HMPs in PTZ-induced acute seizure model
Intraperitoneal administration of PTZ produced GTCS in 100% of the animals in the PTZ group while all the animals were protected from the onset of GTCS in the clonazepam group. None of the pretreatment drugs could negate the onset of myoclonic jerks and forelimb clonus, but the reference drug clonazepam provided 100% protection against the onset of GTCS, and thus the onset of GTCS was used as the parameter to assess the efficacy of the test drugs against the acute administration of PTZ. Seizure
Discussion
PTZ (70 mg/Kg; i.p.) administration in acute model produced GTCS in 100 % of the animals in PTZ group. PTZ-induced seizures hinder GABA-A receptor activity and downregulate GABAergic tone which is negated by clonazepam through direct action on the benzodiazepine receptors, thereby upregulating GABAergic neurotransmission [38], [39]. Owing to such effects, clonazepam protected all the animals from GTCS. The CV HMPs, although could not prevent the onset of GTCS, delayed the GTCS besides reducing
Acknowledgement
The authors would like to thank Amity administration for supporting and encouraging the work from the very beginning. We would also like to thank faculty and staff of Amity Institute of Neuropsychology and Neurosciences (AINN) and Amity Institute of Indian System of Medicine for providing infrastructure and logistic support.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Conflict of interest
No conflict of interest is declared by the authors.
Author contributions
- 1.
Priya Mishra: Performed the entire animal experiments, compiled the data, and did the statistical data analysis. Wrote the initial draft of the article. Finalized the final version of the manuscript.
- 2.
Satyendra Kumar Rajput: Designed and supervised the entire experiments in collaboration with JKS, provided lab infrastructure and facilities for performing experiments, traditional medicine expert who decided the drug and its potencies, concentration and route of administration, advised regarding
References (90)
- et al.
Role of inflammation in epilepsy and neurobehavioral comorbidities: Implication for therapy
Eur J Pharmacol
(2018) - et al.
Ginkgo biloba L. attenuates spontaneous recurrent seizures and associated neurological conditions in lithium-pilocarpine rat model of temporal lobe epilepsy through inhibition of mammalian target of rapamycin pathway hyperactivation
J Ethnopharmacol
(2017) - et al.
Cellular mechanisms underlying acquired epilepsy: the calcium hypothesis of the induction and maintenance of epilepsy
Pharmacol Ther
(2005) - et al.
Anticonvulsant activity of an active fraction extracted from Crinum jagus L. (Amaryllidaceae), and its possible effects on fully kindled seizures, depression-like behaviour and oxidative stress in experimental rodent models
J Ethnopharmacol
(2016) - et al.
Effect of newer anti-epileptic drugs (AEDs) on the cognitive status in pentylenetetrazol induced seizures in a zebrafish model
Prog Neuropsychopharmacol Biol Psychiatry
(2019) - et al.
Ferulic acid exhibits antiepileptogenic effect and prevents oxidative stress and cognitive impairment in the kindling model of epilepsy
Life Sci
(2017) - et al.
Cicutoxin from Cicuta virosa—a new and potent potassium channel blocker in T lymphocytes
Biochem Bioph Res Co
(1996) - et al.
The efficacy and side effects of topiramate on refractory epilepsy in infants and young children: a multi-center clinical trial
Seizure
(2005) - et al.
Neuronal nitric oxide synthase contributes to pentylenetetrazole-kindling-induced hippocampal neurogenesis
Brain Res Bull
(2016) - et al.
Piperine-loaded chitosan-STPP nanoparticles reduce neuronal loss and astrocytes activation in chemical kindling model of epilepsy
Int J Biol Macromol
(2018)