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

Antidepressant activity of tricin-7-O-glucoside and anxiolytic-like effect of harmane from Passiflora coriacea Juss. On mice

ETHNOPHARMACOLOGICAL RELEVANCE

Passiflora coriacea Juss., a medicinal plant in the family Passifloraceae, is widely used to treat anxiety and depression in Mexican folk medicine. However, its chemical profile and biological activity have not been characterized.

AIM OF THE STUDY

The aim of the study was to determine the antidepressant activity, anxiolytic effect, and chemical profile of Passiflora coriacea.

MATERIALS AND METHODS

An organic fraction (PcEA) from a hydroalcoholic extract of the aerial parts of P. coriacea was obtained, followed by a chemical analysis and separation, yielding six fractions (PcEA, T1, T2, T1.1, T2.1, and T2.2). Male ICR mice were used to determine the antidepressant activity of selected treatments (PcEA, T1, T2, and T1.1) based on a forced swim test (FST). The anxiolytic-like effects of various treatments (PcEA, T1, T2, T2.1, and T2.2) were determined using the elevated plus maze (EPM) test.

RESULTS

The organic fraction of P. coriacea decreased anxiety-like behaviors in mice and increased the time of mobility in the FST. After chemical separation, two compounds were isolated from the species with antidepressant activity and anxiolytic-like effects, T1.1 (tricin 7-O-glucoside) and T2.2 (harmane), respectively.

CONCLUSIONS

Compounds isolated from P. coriacea exerted anxiolytic and antidepressant effects in mice based on the EPM and FST. The flavonoid tricin-7-O-glucoside and the alkaloid harmane contributed to these biological activities.

Therapeutic Role of Desmodium Species on its Isolated Flavonoids

Secondary metabolites are an important part to play a major role in society and it was isolated from plant flavonoids and useful in the treatment of various kinds of diseases in the human race. They are widely used as food and nutrition supplements as well as antioxidants. Traditionally, the Desmodium species are an important tool for the secondary metabolites to treat various diseases. Desmodium triquetrum (Fabaceae) one of the Indian medicinal plants is widely used in the treatment of asthma and inflammation. Three flavonoids isolated from Desmodium triquetrum Linn namely Baicalein, Naringin and Neohesperidin are useful as antioxidants, food and nutrition supplements, that help the body to function efficiently while protecting it against toxins as well stressors. The role of flavonoids may be due to the presence of the phenolic compound. Similarly, the flavonoids such as gangetin, gangetinin, desmocarpin and desmodin isolated from the species Desmodium gangeticum are responsible for antileishmanial, antioxidant, anti-arthritic, and immunomodulatory activities. Additionally, isolated flavanoids from the species Desmodium triflorum show antibacterial, antiepileptic, antifungal, and radioprotective activities. So, the aim of the present study, based on the literature miming from the desmodium species is to acknowledge the importance of flavonoids in human health as dietary food supplements and therapeutic uses.

Antiseizure Effects of Peganum harmala L. and Lavandula angustifolia

Peganum harmala L. and Lavandula angustifolia are two traditional herbs with probable antiseizure effects. This study evaluated the effects of these two herbal extracts on pentylenetetrazol- (PTZ-) induced seizures in mice. We prepared hydroalcoholic extracts using P. harmala seeds and the aerial parts of L. angustifolia and then randomly divided 190 mice into 19 groups. Normal saline (10 mg/kg), diazepam (2 mg/kg), P. harmala (2.5, 5, 10, 15, 30, 45, and 60 mg/kg), and L. angustifolia (200, 400, 600, and 800 mg/kg) were intraperitoneally (IP) administrated 30 min before an IP administration of PTZ (90 mg/kg). Animals were observed for behavioral changes for one hour. In addition, the effects of flumazenil and naloxone on the antiseizure activity of P. harmala and L. angustifolia were assessed. P. harmala showed antiseizure activity at the dose of 10 mg/kg; it prolonged the seizure latency and decreased the seizure duration. The mortality protection rate was 90% for this herbal extract. L. angustifolia (600 mg/kg) prolonged the seizure latency and decreased both seizure duration and mortality. Neither flumazenil nor naloxone significantly reversed the antiseizure activities of P. harmala and L. angustifolia. In mice, the hydroalcoholic extracts of P. harmala and L. angustifolia showed antiseizure activity against PTZ-induced seizures. We could not delineate the exact antiseizure mechanisms of these extracts in the current study.

Exploring the Anticonvulsant Activity of Aqueous Extracts of Ficus benjamina L. Figs in Experimentally Induced Convulsions

Background. Ficus benjamina L. is an evergreen tree, native to Southeast Asia, and often known as a weeping fig. Its latex and fruit extracts are used by indigenous cultures to cure skin conditions, inflammation, vomiting, leprosy, malaria, and nasal ailments. The aqueous extract of the figs of Ficus benjamina L. has various therapeutic values, including biological activities on the central nervous system. Materials and Methods. The extract of the dried figs of Ficus benjamina L. (FBE) was prepared by defatting with petroleum ether for 16 h followed by soxhelation with 70% methanol (1 : 10 w/v) for 24 h, and standardization of the extract was carried out using HPLC with 5-HT as a standard. Electroconvulsions were induced by the maximal electroshock model, and chemoconvulsions were induced by picrotoxin. Results. The HPLC chromatogram of the Ficus benjamina L. extract showed an absorption peak with a retention time of 1.797 min, similar to that observed with standard serotonin (5-HT) solution. In the maximal electroshock model, FBE significantly reduced the duration of the tonic hind limb extensor and extensor-to-flexor ratio (E/F ratio) in a dose-dependent manner. Moreover, in the picrotoxin-induced seizure model, FBE increased the seizure latency and decreased the duration of tonic-clonic convulsions dose-dependently. We confirmed the anticonvulsant activity of the FBE extract as it attenuated both maximal electroshock and picrotoxin-induced convulsions. Conclusion. The in vivo studies revealed that the Ficus extract was found to protect the animals in electroshock-induced and picrotoxin-induced convulsions.

Studying CNS effects of Traditional Chinese Medicine using zebrafish models

ETHNOPHARMACOLOGICAL RELEVANCE

Although Traditional Chinese Medicine (TCM) has a millennia-long history of treating human brain disorders, its complex multi-target mechanisms of action remain poorly understood. Animal models are currently widely used to probe the effects of various TCMs on brain and behavior. The zebrafish (Danio rerio) has recently emerged as a novel vertebrate model organism for neuroscience research, and is increasingly applied for CNS drug screening and development.

AIM OF THE STUDY

As zebrafish models are only beginning to be applied to studying TCM, we aim to provide a comprehensive review of the TCM effects on brain and behavior in this fish model species.

MATERIALS AND METHODS

A comprehensive search of published literature was conducted using biomedical databases (Web of Science, Pubmed, Sciencedirect, Google Scholar and China National Knowledge Internet, CNKI), with key search words zebrafish, brain, Traditional Chinese Medicine, herbs, CNS, behavior.

RESULTS

We recognize the developing utility of zebrafish for studying TCM, as well as outline the existing model limitations, problems and challenges, as well as future directions of research in this field.

CONCLUSIONS

We demonstrate the growing value of zebrafish models for studying TCM, aiming to improve our understanding of TCM' therapeutic mechanisms and potential in treating brain disorders.

Status analysis of herbal drug therapies in epilepsy: advancements in the use of medicinal plants with anti-inflammatory properties

BACKGROUND

Use of plants and plant products in health care has shown exponential increase in past two decades.

INTRODUCTION

In-spite of the availability of well-established pharmacotherapy for epilepsy, a large no of population still explores alternative treatments due to refractory seizures, adverse effects of drugs, chronic treatment, inaccessibility of standard therapies in rural areas and the social stigma attached to the disease. Various studies on medicinal plants showed the protective effect of herbals in animal models of epilepsy.

METHOD

In the present review, a status analysis of the traditional use of various medicinal plants in epilepsy with a special focus on plats having anti-inflammatory potential is recorded.

RESULT AND CONCLUSION

The shortcomings of research on medicinal plants which needs to be explored further in order to tackle the growing need of safer and effective drugs for epilepsy are discussed. Overall, there is a huge scope of herbal drugs in CNS disorders especially epilepsy, either as an adjunct by reducing the dose and thus side effects of standard anti-epileptic drugs or as standalone agent . Although, there is still an urgent need of well planned randomized controlled clinical trials to validate their efficacy and safety.

Vitexin Possesses Anticonvulsant and Anxiolytic-Like Effects in Murine Animal Models

Different types of epilepsy and forms of pathological anxiety have been described as significant neurological disorders that may exist as comorbidities. Some of those disorders share the association of affected limbic areas/neuropathological triggers as well as the use of drugs for their clinical management. The aim of this work was to investigate the anticonvulsant and anxiolytic properties of the vitexin (apigenin-8-C-glucoside), since this compound is a flavonoid usually found as one of the major constituents in several medicinal plants claimed as anxiolytics and/or anticonvulsants. This investigation was performed by the use of a series of classical murine animal models of chemically induced-seizures and of anxiety-related tests (open-field, elevated plus-maze, and light-dark box tests). Here, we show that the systemic administration of vitexin (1.25; 2.5 and 5 mg/kg; i.p.) exhibited selective protection against chemically-induced seizures. Vitexin did not block seizures evoked by glutamate receptors agonists (NMDA and kainic acid), and it did not interfere with the latencies for these seizures. Conversely, the same treatments protected the animals in a dose-dependent manner against the seizures evoked by the Gabaergic antagonists picrotoxin and PTZ and rise the latency time for the first seizure on non-protected animals. The higher dose of vitexin protected 100% of animals against the tonic-clonic seizures triggered by GABA antagonists. The results from open-field, elevated plus-maze, and light-dark box tests indicated the anxiolytic properties of vitexin at similar range of doses described for the anticonvulsant action screening. Furthermore, these results pointed that vitexin did not cause sedation or locomotor impairment on animals. The selective action of vitexin against picrotoxin and PTZ may reinforce the hypothesis by which this compound acts mainly by the modulation of GABAergic neurotransmission and/or related pathways. This could be useful to explain the dual activity of vitexin as anticonvulsant and anxiolytic, and highlight the pharmacological interest on this promising flavonoid.

Passiflora caerulea L. fruit extract and its metabolites ameliorate epileptic seizure, cognitive deficit and oxidative stress in pilocarpine-induced epileptic mice

The anticonvulsant potential of aqueous fruit extract of Passiflora caerulea (PCAE) was evaluated in swiss albino mice induced by pilocarpine. The antioxidant activities of PCAE were determined which showed strong antioxidant activity and the polyphenol compounds such as ginsenoside, naringenin, chrysoeriol 8-c-glucoside, luteolin-6-C-glucoside, apigenin-6,8-di-C-β-D-glucopyranoside were profiled through RP-HPLC and UPLC-ESI-MS/MS. Chronic effects of PCAE on pilocarpine (85 mg/kg; i.p)-induced convulsions were evaluated in Swiss adult male albino mice. PCAE at 100 and 200 mg/kg, (p.o.) and diazepam (5 mg/kg, i.p) were administered once daily for 15 days. In Y-maze test, percentage of correct entry by pilocarpine administered animals were significantly lower when compared to control, whereas PCAE at both doses improved the alteration score significantly. Administration of higher dose (200 mg/kg) of PCAE significantly delayed onset of convulsions and decreased duration of clonic convulsions. Association of ROS production during seizure period was further confirmed by histopathological studies revealing loss of normal neuronal cells in hippocampus region. The data obtained showed anticonvulsant activity and improved cognitive function; reduced the oxidative damage and significantly activated the cholinergic neurotransmission in a dose dependent manner similar to diazepam which is evident in the biochemical parameters and histopathological study, suggesting therapeutic potential for epilepsy and neurodegeneration.

Vitexin as an active ingredient in passion flower with potential as an agent for nicotine cessation: vitexin antagonism of the expression of nicotine locomotor sensitization in rats

CONTEXT

Nicotine, a bioactive component of tobacco, is highly addictive. Numerous therapies have been developed for smoking cessation, and all have met with limited success. Our laboratory has previously shown that an extract of Passiflora incarnata Linn. (Passifloraceae) antagonized the expression of nicotine locomotor sensitization in rats.

OBJECTIVE

This study examined the ability of vitexin, a flavonoid found in P. incarnata, to ameliorate the signs of nicotine sensitization in rats.

MATERIALS AND METHODS

Male Wistar rats were administered 0.4 mg/kg nicotine or vehicle (n = 16-18 per group) once a day for four consecutive days. Nicotine administration produces sensitization of locomotor activity. On the fifth day, locomotor activity was monitored as rats from each treatment group were administered either 30 or 60 mg/kg vitexin or its vehicle (n = 4-6 per group) 30 min before a challenge dose of 0.4 mg/kg nicotine.

RESULTS

The challenge dose of nicotine resulted in locomotor activity in rats sensitized to nicotine for 4 days that was approximately twice that measured in rats treated with vehicle during the sensitization phase. Rats sensitized to nicotine and then treated with 60 mg/kg vitexin prior to the nicotine challenge exhibited a level of locomotor activity equivalent to the vehicle-treated controls.

DISCUSSION

Vitexin antagonized the expression of nicotine locomotor sensitization in rats as the whole extract did in the previous study.

CONCLUSION

Vitexin should be examined in future studies to evaluate its potential for treating nicotine addiction in humans.

Role Identification of Passiflora Incarnata Linnaeus: A Mini Review

Some species of traditional herbal medicine has a history of use, most traditional natural herbs have been used for various diseases such as diabetes, hypertension, and obesity. Among them, Passiflora incarnata L. is a traditional natural medicine, flowers as well as berries, roots, and leaves have been used as a medicine. It has been used as a natural medicine for the treatment of insomnia and anxiety for a longtime in Europe, and it has been used primarily for sedation tea in North America. Moreover, Passiflora incarnata L. is widely used anti-asthmatic, analgesic and sedation in Brazil. In other words, Passiflora incarnata L. has been used to treat a sedative, dysmenorrhea, insomnia, cancer, etc. in many countries. Present review of the plants showed a wide range of pharmacological activity in anxiolytic relax the clinical disease, such as anti-inflammatory, anxiety and antioxidant. In addition, Passiflora incarnata L. affects menopause symptoms such as vasomotor symptoms, insomnia, and depression. This review aims to provide the latest information on specific functional components of Passiflora incarnata L. especially the results of clinical trials will provide new insights into opportunities for the future development of natural medicines and doors will be used for purposes of analysis.

Anticonvulsant activity of Pseudospondias microcarpa (A. Rich) Engl. hydroethanolic leaf extract in mice: The role of excitatory/inhibitory neurotransmission and nitric oxide pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Pseudospondias microcarpa (A. Rich) Engl. is a plant used for managing various diseases including central nervous system disorders.

AIM OF THE STUDY

This study explored the anticonvulsant activity of P. microcarpa hydroethanolic leaf extract (PME) as well as possible mechanism(s) of action in animal models.

METHODS

Effects of PME was assessed in electroconvulsive (the maximal electroshock and 6-Hz seizures) and chemoconvulsive (pentylenetetrazole-, picrotoxin-, isoniazid-, 4-aminopyridine-, and strychnine-induced seizures) models of epilepsy. In addition, effect of the extract on the nitric oxide pathway and GABA_A receptor complex was evaluated.

RESULTS

The extract (30, 100 and 300mgkg^-1, p.o.) significantly delayed the onset as well as decreased the duration and frequency of pentylenetetrazole-, picrotoxin- and strychnine-induced seizures. In addition, PME pre-treatment significantly improved survival in the 4-aminopyridine- and isoniazid-induced seizure tests. Furthermore, the extract protected against 6-Hz psychomotor seizures but had no effect in the maximal electroshock test. The anticonvulsant effect of PME (100mgkg^-1, p.o.) was also reversed by pre-treatment with flumazenil, L-arginine or sildenafil. However, L-NAME or methylene blue (MB) augmented its effect.

CONCLUSION

Results show that PME has anticonvulsant activity and may probably be affecting GABAergic, glycinergic, NMDA, K⁺ channels and nitric oxide-cGMP pathways to exert its effect.

Anticonvulsant Effects of Aerial Parts of Verbena officinalis Extract in Mice: Involvement of Benzodiazepine and Opioid Receptors

To evaluate the anticonvulsant activity of the aerial parts of Verbena officinalis used traditionally by local Iranians for the treatment of convulsion. The anticonvulsant activity of the extract was assessed in pentylenetetrazole (PTZ) and maximal electroshock (MES) induced seizures in mice. Diazepam was used as reference drug. In addition, for investigating the mechanism of V officinalis in PTZ model, flumazenil and naloxone were injected before V officinalis. The extract showed no toxicity and significantly increased the period taken before the onset and decreased the duration of the seizures induced by PTZ. In the MES test, V officinalis displayed significant reduction in hind limb tonic extension duration in a dose-dependent manner. The results propose that V officinalis ethanolic extract has anticonvulsant activity against seizure. It seems that these effects may be related to potentiating of GABAergic system. Moreover, this study supports the use of this plant by local Iranians in order to treat convulsion.

Anticonvulsant activity of Dorema ammoniacum gum: evidence for the involvement of benzodiazepines and opioid receptors

This study investigated the anticonvulsant activity and possible mechanism of action of an aqueous solution of Dorema ammoniacum gum (DAG) which has been used traditionally in the treatment of convulsions. In this study, the anticonvulsant activity of DAG was examined using the pentylentetrazole (PTZ) model in mice. Thirty male albino mice were divided randomly and equally to 5 groups, and pretreated with normal saline, diazepam, or various doses of DAG (500, 700, and 1000 mg/kg, i.p.), prior to the injection of PTZ (60 mg/kg, i.p.). The latency and duration of seizures were recorded 30 min after PTZ injection. Pretreatments with naloxone and flumazenil in different groups were studied to further clarify the mechanisms of the anticonvulsant action. Phytochemical screening and thin layer chromatography (TLC) fingerprinting of ammoniacum gum was also determined. DAG showed significant anticonvulsant activity at all doses used. The gum delayed both the onset and the duration of seizures induced by PTZ. Treatment with flumazenil before DAG (700 mg/kg) inhibited the effect of gum on seizure duration and latency to some extent and administration of naloxone before DAG also significantly inhibited changes in latency and duration of seizure produced by DAG. The percentage inhibition was greater with naloxone than with flumazenil. This study showed that DAG had significant anticonvulsant activity in PTZ-induced seizures, and GABAergic and opioid systems may be involved. More studies are needed to further investigate its detailed mechanism.

Anticonvulsant Effects of Lippia citriodora (Verbenaceae) Leaves Ethanolic Extract in Mice: Role of GABAergic System

Background:

Lippia citriodora Kunth is one of the Iranian traditional medicines for the treatment of convulsive disorders. The goal of this study is to investigate the anticonvulsant activity of the plant's leave ethanolic extract against electro- and chemoconvulsant-induced seizures in mice.

Methods:

The anticonvulsant activity of the extract (200, 400, 800 mg/kg, per os, p.o.) was investigated in pentylenetetrazole (PTZ) and maximal electroshock (MES)-induced seizures in mice. Diazepam (1 mg/kg) and phenytoin (25 mg/kg) intraperitoneally (i.p.) were used as reference drugs. In addition, for investigating the role of GABAergic system, flumazenil (2 mg/kg, i.p.) was also injected before L. citriodora.

Results:

The extract had not any toxicity and significantly decreased the duration and increased the latency of the seizures induced by PTZ (90 mg/kg). In the MES test, L. citriodora displayed statistically significant reduction in hind limb tonic extension duration in a nondose-dependent manner. Flumazenil reversed the anticonvulsant activity of the plant's extract in the PTZ model.

Conclusions:

The results propose that L. citriodora leave ethanolic extract has anticonvulsant activity against convulsive disorders. It seems that this plant's extract generates its antiseizure effect through GABAergic system potentiation. Further studies will be needed in order to investigate the exact mechanisms of it. Moreover, one may conclude that the present results are in accordance with the positive effect of L. citriodora extract to treat convulsion mentioned in old Iranian literature.

Passiflora incarnata attenuation of neuropathic allodynia and vulvodynia apropos GABA-ergic and opioidergic antinociceptive and behavioural mechanisms

Background

Passiflora incarnata is widely used as an anxiolytic and sedative due to its putative GABAergic properties. Passiflora incarnata L. methanolic extract (PI-ME) was evaluated in an animal model of streptozotocin-induced diabetic neuropathic allodynia and vulvodynia in rats along with antinociceptive, anxiolytic and sedative activities in mice in order to examine possible underlying mechanisms.

Methods

PI-ME was tested preliminary for qualitative phytochemical analysis and then quantitatively by proximate and GC-MS analysis. The antinociceptive property was evaluated using the abdominal constriction assay and hot plate test. The anxiolytic activity was performed in a stair case model and sedative activity in an open field test. The antagonistic activities were evaluated using naloxone and/or pentylenetetrazole (PTZ). PI-ME was evaluated for prospective anti-allodynic and anti-vulvodynic properties in a rat model of streptozotocin induced neuropathic pain using the static and dynamic testing paradigms of mechanical allodynia and vulvodynia.

Results

GC-MS analysis revealed that PI-ME contained predominant quantities of oleamide (9-octadecenamide), palmitic acid (hexadecanoic acid) and 3-hydroxy-dodecanoic acid, among other active constituents. In the abdominal constriction assay and hot plate test, PI-ME produced dose dependant, naloxone and pentylenetetrazole reversible antinociception suggesting an involvement of opioidergic and GABAergic mechanisms. In the stair case test, PI-ME at 200 mg/kg increased the number of steps climbed while at 600 mg/kg a significant decrease was observed. The rearing incidence was diminished by PI-ME at all tested doses and in the open field test, PI-ME decreased locomotor activity to an extent that was analagous to diazepam. The effects of PI-ME were antagonized by PTZ in both the staircase and open field tests implicating GABAergic mechanisms in its anxiolytic and sedative activities. In the streptozotocin-induced neuropathic nociceptive model, PI-ME (200 and 300 mg/kg) exhibited static and dynamic anti-allodynic effects exemplified by an increase in paw withdrawal threshold and paw withdrawal latency. PI-ME relieved only the dynamic component of vulvodynia by increasing flinching response latency.

Conclusions

These findings suggest that Passiflora incarnata might be useful for treating neuropathic pain. The antinociceptive and behavioural findings inferring that its activity may stem from underlying opioidergic and GABAergic mechanisms though a potential oleamide-sourced cannabimimetic involvement is also discussed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1048-6) contains supplementary material, which is available to authorized users.

Passiflora actinia hydroalcoholic extract and its major constituent, isovitexin, are neuroprotective against glutamate-induced cell damage in mice hippocampal slices

OBJECTIVES

To investigate whether Passiflora actinia hydroalcoholic extract and its major constituent, isovitexin, protect mice hippocampal brain slices from glutamate-induced neurotoxicity.

METHODS

Neuroprotective effect of the extract against glutamate-induced excitotoxicity (10 mm) was evaluated through cell viability of hippocampal slices. The extract or its flavonoids were directly applied to hippocampal slices and then subjected to glutamate-induced toxicity. Alternatively, hippocampal slices from extract-treated mice were also subjected to the same toxicity protocol.

KEY FINDINGS

Mice supplementation with the extract protected hippocampal slices from in-vitro neurotoxicity. When directly applied to hippocampal slices, the extract showed a higher neuroprotective potential than a commercial dry extract of Passiflora incarnata, which was related to P. actinia extract which had higher isovitexin and total flavonoid content expressed as isovitexin. Isovitexin, but not apigenin, induced a similar neuroprotective response when applied alone, at a concentration equivalent to that found in the extract.

CONCLUSIONS

This study highlights new neuropharmacological activity of the Passiflora genus, suggesting that it can act as modulator of the glutamatergic system. The search for improved pharmacotherapies with novel mechanisms of action has been shown of great importance for the treatment of resistant neurological and psychiatric disorders.

Ayurveda and botanical drugs for epilepsy: Current evidence and future prospects

The understanding of epilepsy has progressed since its earliest impression as a disease associated with paranormal and superstitious beliefs. Landmark advances have been made in deciphering the pathophysiological substrates involved in the disease process, and treatment advances have contributed significantly to ameliorating the seizures. However, disease-modifying agents are yet to be discovered. Ayurveda is a system of medicine that stresses a holistic approach to disease, and treatment is focused on disease modification and symptom management. Herbs form the core of Ayurveda medicine; though many of them have been studied for their anticonvulsant activity, very few actually mention the reference of these herbs in Ayurveda literature. Other therapeutic interventions used in Ayurveda are relatively unexplored, and future research will need to focus on this. The current manuscript briefly discusses the understanding of epilepsy as per Ayurveda and reviews herbs that have been studied for their anticonvulsant activity mentioned in Ayurveda literature. This article is part of a Special Issue entitled "Botanicals for Epilepsy".

Passiflora incarnata L.: ethnopharmacology, clinical application, safety and evaluation of clinical trials

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Passiflora incarnata Linnaeus comprises approximately 520 species belonging to the Passifloraceae family. The majority of these species are vines found in Central or South America, with rare occurrence in North America, Southeast Asia and Australia. The genus Passiflora incarnata has long been used in traditional herbal medicine for the treatment of insomnia and anxiety in Europe, and it has been used as a sedative tea in North America. Furthermore, this plant has been used for analgesic, anti-spasmodic, anti-asthmatic, wormicidal and sedative purposes in Brazil; as a sedative and narcotic in Iraq; and for the treatment of disorders such as dysmenorrhoea, epilepsy, insomnia, neurosis and neuralgia in Turkey. In Poland, this plant has been used to treat hysteria and neurasthenia; in America, it has been used to treat diarrhoea, dysmenorrhoea, neuralgia, burns, haemorrhoids and insomnia. Passiflora incarnata L. has also been used to cure subjects affected by opiate dependence in India. This review aims to provide up-to-date information about the pharmacology, clinical efficacy and clinical safety of Passiflora incarnata L. based on the scientific literature. In particular, the methodological accuracy of clinical trials is analysed in accordance with current consolidated guidelines on reporting the clinical efficacy of herbal medicine, offering new insight into opportunities for future research and development.

METHODS

A bibliographic investigation was performed by examining the available data on Passiflora incarnata L. from globally accepted scientific databases and search engines (Pubmed, Scopus and Web of Science, SciFinder and Google Scholar). We selected studies, case reports, and reviews addressing the pharmacology and safety of Passiflora incarnata.

RESULTS

Although numerous Passiflora incarnata L. derivative products have been commercialised as alternative anxiolytic and sedative remedies based on their long tradition of use, their supposed efficacy does not appear to be adequately corroborated by the literature, with clinical studies often featuring inadequate methodologies and descriptions of the products under investigation. This medicinal plant has shown a wide spectrum of pharmacological activities in preclinical experiments, including anxiolytic, sedative, antitussive, antiasthmatic, and antidiabetic activities. The plant has a good safety profile. The clinical trials that we included in this review were designed to evaluate and in some cases confirm promising observations of preclinical pharmacological activity, and the methodological limits of these studies are characterised here.

CONCLUSION

In conclusion, clinical studies on the effects of products containing herbal preparations based on Passiflora incarnata reveal crucial weaknesses such as poor details regarding the drug extract ratio, limited patient samples, no description of blinding and randomisation procedures, incorrect definition of placebo, and lack of intention to treat analysis. In conclusion, the results of this review suggest that new clinical trials should be conducted using a more rigorous methodology to assess the traditional putative efficacy of Passiflora incarnata L.

Passion flower extract antagonizes the expression of nicotine locomotor sensitization in rats

CONTEXT

Nicotine, a bioactive component of tobacco, is highly addictive. Numerous therapies have been developed or are currently under investigation for smoking cessation, and all have met with limited success and/or side effects, indicating the need for additional therapies.

OBJECTIVE

This study examines the ability of a commerically-available aqueous extract of Passiflora incarnata Linn. (Passifloraceae) to ameliorate the signs of nicotine sensitization using a rat model.

MATERIALS AND METHODS

Rats were administered 0.4 mg/kg nicotine or vehicle once a day for four consecutive days. Nicotine adminstration produces sensitization of locomotor activity, a phenomenon implicated in the development of nicotine dependence. On the fifth day, locomotor activity of the subjects was monitored as rats from each treatment group were administered 800 mg/kg of Passiflora incarnata extract (or its vehicle) followed by a challenge dose of 0.4 mg/kg nicotine.

RESULTS

When given to rats sensitized to nicotine for 4 days, the challenge dose of nicotine increased locomotor activity by more than 2-fold over activity following nicotine challenge in rats treated with vehicle during the sensitization phase. The difference was significant from 15-40 min after nicotine administration. Rats sensitized to nicotine then treated with Passiflora incarnata extract prior to the nicotine challenge exhibited a level of locomotor activity the same as the vehicle-treated controls.

DISCUSSION

Passiflora incarnata extract did antagonize the expression of nicotine locomotor sensitization.

CONCLUSION

Passiflora incarnata extract should be examined in future studies to evaluate its potential for treating nicotine addiction in humans.

Neuroprotective effects of vitexin, a flavonoid, on pentylenetetrazole-induced seizure in rats

Flavonoids are important constituents of food and beverages and have several neuropharmacological activities. Many of these compounds are ligands for γ-aminobutyric acid type A receptors in the central nervous system. This study aimed to investigate the anticonvulsant effects of intracerebroventricularly administered vitexin (5, 7, 4-trihydroxyflavone-8-glucoside), a flavonoid found in plants, in rats treated with pentylenetetrazole (90 mg/kg, intraperitoneally) and to clarify the underlying mechanism. Vitexin (100 and 200 μm, i.c.v) affected minimal clonic seizures and generalized tonic-clonic seizures induced by pentylenetetrazole by increasing the seizure onset time. Pretreatment with flumazenil suppressed the anticonvulsant effects of vitexin during the onset of both the seizures. These results indicate that vitexin has anticonvulsant effects in the brain, possibly through interaction at the benzodiazepine site of the γ-aminobutyric acid type A receptor complex.

Endogenous opioid peptide-mediated neurotransmission in central and pericentral nuclei of the inferior colliculus recruits μ1-opioid receptor to modulate post-ictal antinociception

BACKGROUND

The aim of the present work was to investigate the involvement of the μ1-endogenous opioid peptide receptor-mediated system in post-ictal antinociception.

METHODS

Antinociceptive responses were determined by the tail-flick test after pre-treatment with the selective μ1-opioid receptor antagonist naloxonazine, peripherally or centrally administered at different doses.

RESULTS

Peripheral subchronic (24 h) pre-treatment with naloxonazine antagonised the antinociception elicited by tonic-clonic seizures. Acute (10 min) pre-treatment, however, did not have the same effect. In addition, microinjections of naloxonazine into the central, dorsal cortical and external cortical nuclei of the inferior colliculus antagonised tonic-clonic seizure-induced antinociception. Neither acute (10-min) peripheral pre-treatment with naloxonazine nor subchronic intramesencephalic blockade of μ1-opioid receptors resulted in consistent statistically significant differences in the severity of tonic-clonic seizures shown by Racine's index (1972), although the intracollicular specific antagonism of μ1-opioid receptor decreased the duration of seizures.

CONCLUSION

μ1-Opioid receptors and the inferior colliculus have been implicated in several endogenous opioid peptide-mediated responses such as antinociception and convulsion. The present findings suggest the involvement of μ1-opiate receptors of central and pericentral nuclei of the inferior colliculus in the modulation of tonic-clonic seizures and in the organisation of post-ictal antinociception.

Dual protective effect of Passiflora incarnata in epilepsy and associated post-ictal depression

ETHNOPHARMACOLOGICAL RELEVANCE

Passiflora incarnata L. (Passifloraceae) has been used for the treatment of epilepsy in several traditional systems of medicine.

AIM OF THE STUDY

The aerial parts of Passiflora incarnata contain multiple bioactive metabolites such as, flavonoids (like, chrysin that show CNS depressant activity by agonizing GABA-benzodiazepine receptor), amino acids (like, GABA), harmala alkaloids (reversible monoamine oxidase-A inhibitor), etc. In view of this, the present study was designed to investigate dual protective effect of the hydroethanolic extract of Passiflora incarnata in pentylenetetrazol (PTZ)-induced seizure and associated post-ictal depression.

MATERIALS AND METHODS

Different groups of mice were administered with repeated subconvulsive doses of PTZ (50mg/kg; i.p.) at an interval of 5 days for 15 days. From 5th to 15th day the animals in different groups were administered daily with varying doses of hydroethanolic extract of Passiflora incarnata (150, 300, and 600mg/kg; i.p.), diazepam (2mg/kg; i.p.) and vehicle. On every 5th day, after PTZ treatment, seizure severity (score) was noted. Following convulsive episodes the locomotor activity (using actophotometer) and immobility period (using forced swim test) were also determined. On 15th day after behavioral assessment, the brain serotonin and noradrenaline levels were determined using spectrofluorometric methods.

RESULTS

Treatment with the extract significantly (p<0.05) reduced the seizure severity and immobility period as compared to vehicle control, in a dose and time-dependent manner. Moreover, the extract treatment retained the serotonin and noradrenaline levels of the brain.

CONCLUSIONS

The results of present study concluded that the hydroethanolic extract of Passiflora incarnata suppress PTZ-induced seizures, and ameliorates its associated post-ictal depression, which has been found to be get worsened with the standard antiepileptic drug, diazepam.

Antiepileptic potential of flavonoids fraction from the leaves of Anisomeles malabarica

ETHNOPHARMACOLOGICAL RELEVANCE

The plant Chodara (Anisomeles malabarica R.Br. Family: Lamiaceae) has numerous therapeutic utilities in folk medicine.

AIM OF THE STUDY

To isolate and evaluate the anti-epileptic potential of fractions from the ethyl acetate extract (EAE) of Anisomeles malabarica leaves.

MATERIALS AND METHODS

The EA extract (2.12% w/w) of the leaves of Anisomeles malabarica was prepared and fractionated into total flavonoids fraction (AMFF) and tannins fraction (AMTF), which subsequently evaluated for the antiepileptic activity against PTZ- and MES model in wistar rats. Diazepam and phenytoin (2mg/kg and 25mg/kg, i.p., respectively), were used as a reference drugs. Further, the presence of flavonoid was confirmed by chemical test, TLC and HPTLC were done for the identification of the number of flavonoids with reference to standard.

RESULTS

Single dose pretreatment with AMFF (25 and 50mg/kg, i.p.) has found to be effective against both MES and PTZ-convulsions, but associated with a marked decrease in locomotor activity and motor activity performance (i.e., neurotoxic effects), similar to that of diazepam treatment. Interestingly, chronic treatment with AMFF at lower doses (6.25 and 12.5mg/kg, i.p., 1 week) has also produced significant antiepileptic activity, but without causing neurotoxic effects.

CONCLUSION

Thus, it may be concluded that the flavonoids fraction of the EA extract of Anisomeles malabarica leaves has antiepileptic potential against both MES and PTZ convulsion models. Acute treatment (25 and 50mg/kg, i.p.) is associated with neurotoxic activity. Whereas, chronic treatment (6.25 and 12.5mg/kg, i.p., 1 week) also shown significant antiepileptic effect without causing neurotoxic side effects. However, further research is in progress to determine the component(s) of the flavonoids fraction of Anisomeles malabarica involved and their mechanism of action in bringing about the desirable anti-epileptic effect.

Identification of a Passiflora alata Curtis dimeric peptide showing identity with 2S albumins

Antifungal proteins and peptides, essential compounds for plant defense, have been isolated from several tissues of various plants. These proteins could be used as a natural alternative to control phytopathogenic fungi. In this report a heterodimeric antifungal protein named Pa-AFP1, showing higher identity with the 2S albumin family, was purified by using 70-100% ammonium sulfate saturation and further purification steps such as anionic exchange Q-Sepharose chromatography associated with HPLC reversed-phase C4 chromatography. Analysis by Tricine-SDS-PAGE revealed two peptidic molecular masses of approximately 4500 Da and 7000 Da, in the presence of β-mercaptoethanol, while by removing the reducing agent a single protein with molecular mass of about 11,500 Da was obtained. Moreover, dimer mass was confirmed by MALDI-TOF analyses (11,569.76 Da). The antifungal protein, named Pa-AFP1, efficiently inhibited the growth of filamentous fungi Colletotrichum gloeosporioides, and was added to a short list of 2S albumins with antimicrobial properties. Otherwise, this same peptide showed no activity toward bacteria and yeasts. In summary, this compound could be used in the future to develop biotechnological products for the control of phytopathogenic fungi.

Passiflora incarnata L. (Passionflower) extracts elicit GABA currents in hippocampal neurons in vitro, and show anxiogenic and anticonvulsant effects in vivo, varying with extraction method

Potential mechanisms of Passiflora incarnata extracts and the effect of extraction methods on ingredients and biological effects were explored. Using the same batch of plant material, total flavonoid yields as measured by high-performance liquid chromatography coupled to diode array detection (HPLC-DAD) increased substantially with hot versus cold extraction methods. Whole Passiflora extract induced prominent, dose-dependent direct GABA(A) currents in hippocampal slices, but the expected modulation of synaptic GABA(A) currents was not seen. GABA was found to be a prominent ingredient of Passiflora extract, and GABA currents were absent when amino acids were removed from the extract. Five different extracts, prepared from a single batch of Passiflora incarnata, were administered to CF-1 mice for 1 week in their drinking water prior to evaluation of their behavioral effects. Anticonvulsant effects against PTZ-induced seizures were seen in mice that received 2 of the 5 Passiflora extracts. Instead of the anxiolytic effects described by others, anxiogenic effects in the elevated plus maze were seen in mice receiving any of the 5 Passiflora extracts.

Anticonvulsant activity of berberine, an isoquinoline alkaloid in mice

Berberine, an isoquinoline alkaloid is reported to modulate several neurotransmitter systems like N-methyl-D-aspartate, nitric oxide and serotonin, which modulate convulsions. In addition, it is suggested that Berberis vulgaris may be useful in treatment of convulsion and epilepsy. Therefore, the present study investigated the effects of berberine in pentylenetetrazole, maximal electroshock (MES) and kainic acid (KA)-induced convulsions. The latency for development of convulsions and mortality rate was recorded in these models using mice. The results revealed that in MES-induced seizures model, berberine (10 and 20 mg/kg, i.p.) decreased duration of tonic hind limb extension and percent mortality. Moreover, these doses of berberine also protected mice against KA-induced clonic convulsions and decreased mortality. Berberine also protected mice against NMDA-induced turning behavior. Further, the anticonvulsant doses of berberine did not show any signs of motor in-coordination when tested in rotarod test. In conclusion, berberine exhibits anticonvulsant activity by modulating neurotransmitter systems and may find clinical application.

Outcomes of self-help efforts in anxiety disorders

Anxiety disorders are prevalent mental disorders that are a significant burden on the community. There are effective treatments available, but many people do not seek treatment and there is a lack of professionals available to provide evidence-based treatment to all those with anxiety disorders. Recently, there has been increased attention on ways to cost effectively meet the demand for treatment with minimal cost to health services. Self-help efforts have been proposed to play a role, either as an initial minimal treatment in stepped-care models of treatment, or as strategies undertaken by an individual to prevent a full disorder developing. This review examines what is known from randomized controlled trials about the efficacy of self-help interventions for anxiety disorders.

Pharmaco-Toxicological Aspects of Herbal Drugs Used in Domestic Animals

Herbal drugs are more and more used both in human and veterinary medicine to mitigate and prevent minor diseases and to support conventional medicine using allopathic drugs. Nevertheless, ‘natural product’ does not mean lack of adverse effects, and many people and veterinarians do not know enough about the adverse reactions that can occur following the administration of such drugs in domestic animals. Moreover, herbal products can interact with each other when administered concomitantly or can agonize or antagonize the effects of synthetic drugs administered as primary therapy. The use of non-conventional medicines (NCM) should be considered as a veterinary practise. In this paper, the herbal drugs most utilized in domestic animals, both pets and large animals, are reviewed, as their use is increasing, despite the prejudices of the academic world and some of the adverse effects and interactions that can occur in domestic animals.

Effects of isopulegol on pentylenetetrazol-induced convulsions in mice: possible involvement of GABAergic system and antioxidant activity

The present study investigated the effects of isopulegol, a monoterpene alcohol, in PTZ-induced convulsions and verified possible involved mechanisms. Saline, isopulegol or diazepam were intraperitonealy injected 30 min before PTZ. The latency for development of convulsions and mortality, as well as the mortality protection percentage was recorded. For investigating the involvement of GABAergic system, flumazenil was utilized. The activity of antioxidant enzyme catalase as well as the levels of reduced glutathione and lipid peroxidation were measured in brain hippocampus. Similarly to diazepam, isopulegol significantly prolonged the latency for convulsions and mortality of mice. All animals were protected against mortality at higher dose of isopulegol. Flumazenil pretreatment decreased the prolongation of seizure latency induced by both diazepam and isopulegol, although it was not able to reverse the latency and protection percent for mortality. Isopulegol also significantly prevented PTZ-induced increase in lipid peroxidation, preserved catalase activity in normal levels, and prevented the PTZ-induced loss of GSH in hippocampus of mice. These results suggest that the anticonvulsant and bioprotective effects of isopulegol against PTZ-induced convulsions are possibly related to positive modulation of benzodiazepine-sensitive GABA(A) receptors and to antioxidant properties.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

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.